We've been aboard the Antea in the port of Papeete, Tahiti, for the past 2 days. All the equipment has been taken out of the boxes and put and organized to the 2 laboratories and the scientific PC room. We have to make sure that all the equipment is in working order and properly stored and attached. The team is now complete, and after a few last-minute purchases, it's time to leave.

We cast off around 5.30pm and head north towards the waters of Kiribati. Five days of sailing await us.

Guillaume and David in front of WBAT (Wide Band Autonomous Transceiver, an acoustic equipment)

Lui and Matini who are preparing the zooplankton net also known as Bongo

The departure

I admit that yesterday's blog was short and quickly dispatched, but the sea conditions at the time of our departure weren't exactly favorable, and writing a short article in front of the computer after diner wasn't the best idea I've had. Several of us left the dining table or the office in a hurry to make an offering to the god of the sea and his fish.

It was an eventful night, and we soon realized that some of our belongings were not properly secured and were wandering around with the roll and pitch. The sea and our course were more favorable today, despite the 20 knots of wind.

We're making good progress northwards and should enter Kiribati waters tonight.

The scientific team in front of the Antea boat in Papeete harbor, a few hours before departure.

Calibration of the WBAT, an acoustic instrument to detect micronekton, in the port of Papeete just before departure.

This morning the weather was a little milder, but that didn't last, and this afternoon we still have 20-25 knots of wind on the side, which is making the boat roll. Although most of us got our sea legs, it's still difficult for some of us.

Transit days are long and we need to keep busy. Further tests were carried out on the WBAT, an acoustic instrument for detecting micronekton. We had doubts about the quality of the calibration carried out to ensure accurate and precise measurements. The tests showed nothing abnormal, so the measurements should be good.

Jeremie and Christian testing one of the WBAT's acoustic bases (in orange in the bucket in the foreground).

While the weather forecasts predict 15 knots of wind, we're actually experiencing 20-25 knots, and today the swell is really sideways. So, it's hard to concentrate.

We're still in transit, so we took the opportunity to have a team meeting in the wet lab to go over all the manoeuvres we're going to carry out and distribute the tasks to each of us so that everything runs smoothly.

At 4:00 p.m. the fire alarm sounded (one short ring, one long, one short, one long...) and the crew and scientists gathered on the aft deck for a drill. The crew members whose role it was donned firefighting gear, and the fire hose was unrolled for the exercise.

We are also completing the preparation of the instruments to be ready for our first sampling station on Sunday. The sailors on board have installed volucounters on the Bongo zooplankton net. These are small windmills placed at the entrance to the zooplankton net, which estimate the volume of water filtered to calculate the density of the zooplankton collected.

The entire scientific team in the wet laboratory for a briefing.

Fire safety drill

The seamen install the volucounters on the Bongo zooplankton net

We still have 2 days to steam before reaching our first sampling station at the equator, and we have enough time ahead of us to make a short stop for a fictitious station: station 0.

Martine, the team's chemist and phytoplankton specialist, would like to do a little test by taking water from deep below the surface and the phytoplankton it contains and make it grow under surface light conditions. The objective is to try and understand the effect of light on deep-sea phytoplankton.

So we stopped the boat to launch the rosette carryingwhich carries 12 8-liter sampling bottles and several probes which measure temperature and fluorescence, a phytoplankton indicator. We lowered the rosette to a depth of 110m and the probe tells us that maximum fluorescence is at 90m.

We therefore sampled water at depths of 90, 70, 50, 20 and 5 m for Martine's experiments. Then, using the remaining water, we reviewed all the samples we'll be taking at the real stations, and everyone had a chance to practice to be ready for our first station.

Lui takes water samples to measure salinity.

Preparing the phytoplankton incubation tank (Stephane, Martine and Jean).

We were visited by a few frigatebirds.

It's our last day in transit and we're taking advantage of it for the final briefing and for fine-tuning the instruments so that everything is ready for the first station.

We'll be testing a new sensor that measures bioluminescence. Bioluminescence is the emission of light by living organisms through a chemical reaction. It is present in 75% of marine organisms, from the surface to great depths. The ecological role of bioluminescence is poorly understood, partly because direct observations are virtually non-existent.

The sensor is equipped with a highly sensitive photon detector combined with a pressure sensor. It has been installed on the WBAT and will be lowered to a depth of 500 m. The sensor will take high-frequency measurements to determine the distribution of bioluminescent organisms in the water column.

Jonas and Anais program the bioluminescence sensor.

Briefing in the science room.

We've finally arrived in our work zone. We reached the equator mid-afternoon and started work on sampling station number 1 just before 4pm.

We began with two descents of the rosette, at 200 then 600m, the frame that carries numerous sensors and 8-liter bottles that can be closed at selected depths to sample water.

We then went on to lower 3 acoustic instruments: the WBAT to a depth of 500m, which detects micronekton, and the TAPS and AZFP, which detect zooplankton.

The zooplankton net showed us that the environment was quite rich, and catches with the micronekton trawl were quite substantial, which kept us going until 2am.

The team was satisfied with this first day, and from now on we'll be repeating the same operations every day for the next 14 days.

The catch of the day, caught at 500m depth.

Yesterday we enjoyed the last sunset that we will have the opportunity to admire because from today we are at work when the sun sets.

Today is Sunday, and we're having pastries for breakfast. Martine and Pauline keep a close watch.

We were full of enthusiasm for this second station after the success of Station 1, but we were quickly disillusioned. Everything had gone too well the day before, and today, as soon as we launched the rosette for the first time, we had problems with the electronic cable used to lower the instruments and send them instructions. Nevertheless, we were able to bring back on deck the rosette that was 200 m depth and the electronics engineers began to examine the cable, discovering one problem after another. After a few hours' work, it was clear that the repair was going to take a long time, and we abandoned the idea of lowering the instruments using the electronic cable.

So, we used the hydro winch, which carries a simple cable, and lowered the WBAT for a test run as we'd had no data the day before, and the test was positive, so finally some good news. We also lowered the zooplankton net, the bongo, which carries 2 nets with 0.1 and 0.2 mm mesh; this also worked well.

It was then time to carry out the 2 trawls and unfortunately, just as the captain was ready to set the trawl that was in the water, he realized that he was no longer receiving information on one of the winches. Impossible to set the trawl blind, so the trawl was hauled up and we finished the job with little more than a WBAT test and a zooplankton net, but a lot of repair work ahead for the electronics engineers. A bad day, but hopefully the only one of the mission.

Guillaume, Christian, Vincent and Jonas repair the electronic cable.

Recovery of the Bongo zooplankton net.

After yesterday's fiasco, we decided to stay on site at station 2 to do another complete station. Indeed, since station 1 and for a few more stations, we're located in the upwelling zone (upwelling of cold, saltier and richer deep waters), but as we head west, we'll quickly enter the warm pool (very warm, less salty and poorer waters). So, we don't want to miss our chance to characterize the upwelling zone so that we can compare it with the warm waters to the west, where we'll be doing a lot of sampling.

The electronics engineers spent the day repairing the winch of the electronic cable used to lower the instruments into the water, and the trawl control system. They worked on the aft deck, with an air temperature of 30°C and surface water at 28°C, which doesn't cool the atmosphere. Their efforts paid off, and at 2.30pm the rosette test proved conclusive.

With some trepidation, we started our station at 4pm and the first rosette run went well. But on the second rosette the alarms went off again and we had to cancel this second operation. The fault probably lay with the light sensor, which had taken on some water. We then carried on with the rest of the operations without any problems until the second trawl, which brought back its share of strange organisms, notably hatchetfish.

Christian and Guillaume perform precision welding to repair the electronic cable.

A ten-centimetre hatchet fish.

Perched on the aft gantry, this red-footed booby followed with interest what was happening on the deck for most of the day.

Accoustic is fantastic!

Acoustic measurements are carried out continuously along ANTEA's route. The sounders fitted to the ship's hull use acoustic waves to detect life beneath the boat at depths of up to 1,000 meters. Acoustic waves propagate very well in water, unlike light. Dolphins and whales have been using this principle for millions of years to detect their prey with their sonar.

During Warmalis 3, every 3 seconds, the sounders emit an ultrasonic wave (a ping!) which is reflected when it hits a target such as a fish, bubbles or the ocean floor. Thanks to this reflected signal, known as an echo, the target is positioned at depth. As the vessel moves, zooplankton and fish underneath are detected.

The image obtained from a depth sounder is called an echogram, and its signals provide information on the presence or absence of underwater life. The density of micronekton organisms can then be quantified. Acoustic measurements will highlight the differences in density along the equator between the east and west of our study area.

Acoustic recording at 38 kHz made between September 30 and October 1 in the waters off the Kiribati Islands.

This echogram is a visualization of the echoes received on the echo sounder beneath the vessel. It shows vertical movements (vertical axis from surface to 800m depth) as a function of time (horizontal axis over 24 hours). The colour scale indicates the intensity of the echoes and therefore the presence of organisms (yellow-green for high density, blue-white for low density). Vertical migration is clearly visible at every transition between day and night. At the surface, density is much higher at night than during the day. Between 400 and 700m depth, organisms are more numerous during the day than at night.

Active acoustics has the advantage of being non-intrusive, as there is no disturbance of the marine environment, and no sampling is required. However, to find out which species have been detected by the sounder, it is necessary to fish. Acoustic observation of micronekton complements scientific fishing. To improve understanding of ecosystem functioning and dynamics, these data will then be analysed in relation to environmental data collected during the campaign: current, temperature, salinity, fluorescence.

Here we are at station 4, in the waters of Jarvis, an isolated territory of the United States in the middle of the Pacific with a small uninhabited island and that we won't even see because we're too far from it. Since we started sampling, we've been in the rich waters of the equatorial upwelling, and we can see this in the various samples we collect, with high phytoplankton values and well-filled zooplankton nets.

This is also particularly evident in the micronekton trawl catches. Every evening we carry out 2 trawls, the first an oblique trawl from the surface to 250m depth. This allows us to collect organisms that are always at the surface, but also organisms that live at depth during the day and return to the surface at night. In fact, as you can see from the acoustics (see yesterday's blog), everyday part of the micronekton will make vertical migrations of several hundred meters to rise to the surface at night to feed and then descend during the day to the depths where there is no more light to shelter from visual predators such as tuna. Our second trawl is at depth, trawling horizontally at 500m to catch organisms that don't migrate vertically and that can also be caught by deep-diving tuna such as bigeye.

Since the start of the expedition, all the trawls have come up with a good harvest, and every evening we look forward to seeing the treasures we're going to bring up from the depths, sometimes with some very strange animals. So far, we've caught mostly fish and shrimp; squid and gelatinous organisms are less frequent. Sorting out the organisms keeps us busy for a few hours after the trawling has finished, and we don't go to bed until 2am.

A magnificent large shrimp with very large antennae.

A full trawl with a few squid and jellyfish, but mostly fish and shrimp.

Lui proudly presents us with some of the day's harvest, sorted into groups and packed to go into the freezer before returning to Noumea for identification at the Pacific Community laboratory.

Victory today, everything went off without a hitch. We'd been having problems with our rosette since the start of the campaign and Guillaume, our electronics technician, after several tests, identified the fault and replaced the faulty pumps that were causing us to lose contact with the instrument as soon as we reached important depth. We were therefore able to take all our samples and are relieved and confident for the rest of the mission.

It's a bit like "Groundhog Day", with each day repeating itself with the same events. Everyone, scientists and seamen alike, are now well versed in their respective tasks. We do, however, have a few small events that shake us up a little in our daily routine. Last night, a small seabird landed on the boat. It was a petrel, a bird accustomed to making long journeys at sea without landing. It looked unwell, uncomfortable and no doubt disorientated by the noise and spotlights of the boat in the middle of the night. To prevent him from hurting himself, we put him in a box with a little water in a quiet corner and waited until morning to let him take off.

Guillaume looking after the rosette.

Preparing the zooplankton net.

Sorting the micronekton.

This little petrel was undoubtedly disturbed by the lights of the boat during the night. The following morning it flew away without regret.

The crew in the spotlight

We are 23 on board, 13 crew members and 10 scientists. The crew is essential to the smooth running of the scientific campaigns, as they are responsible for driving the boat and preparing, maintaining and launching the gears and equipments used to collect scientific data.

Every member of the crew has a well-defined role. Arnaud (captain), Rémi (second in command) and Cyrille (lieutenant) are the bridge officers. Among their many tasks, they are responsible for steering the ship, in particular arriving at the stations on time, and for the safety of everyone on board (compliance with working conditions, fire emergency, and illness). During operations, they give permission for gear to be launched, supervise activities on deck and ensure that the vessel is kept stationary (for rosettes) or at a constant speed (during trawling), while taking into account surface and wind currents.

Arnaud at the controls

Cyrille explains Pauline how the radar works

Vincent and Rémi are checking if the lifejackets work well

Louis-Marie (chief engineer), Matthieu (second engineer) and Patrick (master engineer) are in charge of the engine department, ensuring that all the equipment on board is working well: propulsion engines, generators, deck gear (winches, gantry cranes, hydraulics) and auxiliaries (fresh water production, black water drainage). On a daily basis, they carry out preventive maintenance and make rounds to check levels and detect leaks. Mechanics have to be multi-skilled, as they may have to repair the coffee machine or deal with damages.

Patrick (or Popo) is repairing a piece of the trawl gear

Matthieu and Louis-Marie are maintaining the lifeboat

On deck there are Jean (bosun), Vincent (boatswain) and deckhands Alex, Mylène and Stéphane. The five of them are responsible for preparing, maintaining and launching the instruments (rosette and acoustic profilers), the zooplankton nets and the micronekton trawl. They are also responsible for keeping the boat clean and carrying out routine maintenance (painting, maintenance of parts worn by corrosion). The three deckhands also make daily safety rounds, checking for leaks in the engine and galley, and ensuring for instance that all the equipment is properly moored during transit periods.

Mylène and Jean are enjoying a deserved snack break while waiting for the rosette to come back to the surface

Stéphane and Alex on the bridge

Life on board wouldn't be what it is without the presence of Delphine, the head chef, who makes delicious, varied and healthy menus every day, and Gwen, the head waiter, in charge of food management and table service.

Delphine and Gwen are preparing the meal for tonight

Apart from the chef and butler, all the seafarers work on watch, i.e. they take turns every four hours on deck and on the bridge, day and night. Unlike the scientists, who will disembark in Tarawa in the middle of the trip and be replaced by the leg 2 team, the crew will remain on board for the whole of Warmalis 3.

Meet the SAILDRONES

Today, two major events shook up our daily routine. On the one hand, it was Sunday, and in addition to our kitchen team concocting a top-of-the-range menu, it's also traditional to put on your best tropical finery - the floral shirt is de rigueur.

Jeremie, Guillaume, Christian and Valerie at Sunday lunch

On our way to Station 007, we were lucky to sail alongside two technological beauty worthy of James Bond props: SAILDRONES. These surface drones left Hawaii 120 days ago and are remotely piloted by the SAILDRONE team for American NOAA scientists.

Detection of the two SAILDRONES by radar

Estimating the meeting point with navigation software

With the weather cooperating, Guillaume took the opportunity to fly his aerial drone. For 20 minutes, he captured superb videos of ANTEA and the saildrone nearby.

SAILDRONE aerial photo

The uncrewed surface vehicles (USVs) look like a miniature sailboat (7 m long, 5 m wing height, 2 m draft). They move with the wind, and can operate autonomously for up to 1 year. Their role is to collect oceanic and climatic data in real time. This enables scientists to obtain weather data (atmospheric pressure, air temperature and humidity, wind) and oceanographic data (water temperature, salinity, biological activity, marine currents) in isolated locations. Communication is via satellite, and each USVs is equipped with an AIS (automatic identification system) beacon and radar reflectors to ensure safety. For more information, visit https://www.saildrone.com

As one of the saildrones is equipped with the same type of acoustic sounder as the ANTEA, during this day, we made acoustic measurements in parallel with the aim to compare the different set of data collected. This will give us additional information around our study area.

Oceanographic boat « Antea » close to station 007 with a Saildrone at 800 m

Cute phytoplankton

Phytoplankton (vegetal plankton) are micro-algae and cyanobacteria found in surface waters (especially in the first 200 meters), drifting with the currents. These organisms measure between 1 mm and 0.2 µm (0.0000002 mm) for the smallest, and are therefore invisible to the naked eye individually; but their quantity is sometimes so large (efflorescence or bloom) that they color the ocean and can thus be observed by satellite.

Examples of phytoplankton organisms under the microscope: a dinoflagellate (left) and a diatom (right).

Like terrestrial plants, phytoplankton are photosynthetic, i.e. they contain chlorophyll, which enables them to capture solar energy and transform carbon dioxide (CO2) into oxygen (O2) and organic matter. Phytoplankton is called a "primary producer" because it is at the base of the oceanic food web, of which tuna are the top predators; it is therefore indispensable to marine life.

Just as terrestrial plants need fertilizers, phytoplankton need nutrients (especially nitrogen and phosphorus) to thrive. These nutrients are present in greater quantities in the upwelling zone where we have been since the start of the campaign, and we're finding that the waters are rich in phytoplankton. We expect the quantities of nutrients and phytoplankton to decrease as we move westwards into the warm pool. One of the aims of Warmalis 3 is therefore to study how this east-west gradient impacts the distribution and activity (primary production) of phytoplankton and other ecosystem components. Every day we sample water at different depths with the rosette to analyze the quantity of nutrients. Filtration in the onboard laboratory and incubation on deck (for 24 hours) are also carried out to measure phytoplankton biomass and photosynthetic activity.

Martine, Lui and Jonas incubating phytoplankton

Martine filters water incubated for 24h

Unfortunately, we once again had problems with our electronic cable, and the electronics engineers had to intervene once again, delaying the start of work by 2-3 hours. We therefore adapted the sampling plan and cancelled a number of operations. Adaptation is the watchword when working at sea, because despite months of preparation, trying to think of every eventuality, there are always unforeseen circumstances and repairs to be made. So, it's important to always have spare parts for all the equipment, and a lot of ingenuity and perseverance.

The team on standby while the electronics technicians repair the cable.

Last night in the trawls we had specimens we hadn't seen until now:

• A small cookie-cutter shark measuring around forty centimetres, which we quickly measured and weighed before returning it to the water alive and well. These small sharks prey on much larger animals such as tuna and marine mammals, quickly scooping out a few centimetres of flesh with their powerful, sharp-toothed jaws.





• A strange black-skinned fish whose mouth and eyes are turned upwards and which seems to have a highly-developed throat with rays.





• A pelagic (i.e. open-water) scorpionfish called Ectreposebastes, rarely seen.

This is our second and last station in the waters of the Phoenix Islands, after having visited the waters of the Line Islands at the start of the mission and before soon visiting the waters of the Gilbert Islands. These 3 remote archipelagos (1000 km between the Gilberts and the Phoenix and 2000 km between the Phoenix and the Line island) constitute 3 distinct economic zones of the same country: Kiribati. In fact, we'll soon be making a stopover in this country's capital atoll, Tarawa, for a change of scientific team.

For our tenth station, we were treated to a beautiful late afternoon sky.

We put the Bongo in the water to sample zooplankton between the surface and 250m depth. This device consists of 2 nets with different mesh sizes of 200 micrometres (0.2mm) and 100 micrometres (0.1mm). At night, the surface layer, the first 200 meters, is richer in zooplankton than deeper water. These small organisms, many of which are crustaceans, feed on phytoplankton, detritus or smaller zooplankton. Like micronekton, some zooplankton species also make vertical migrations between the surface and the depths, depending on day and night. Zooplankton constitutes the food of a large portion of the micronekton organisms.

The zooplankton team waits for the return of the Bongo to collect the samples.

A moment of relaxation for the crew before launching the next piece of equipment.

The micronecton team hard at work: sorting, measuring and weighing the gelatinous organisms while they're still fresh, noting and preparing labels, preparing bags with water for specimen preservation and coming up with inventive names such as black fish or shiny fish for specimens that will require a thorough examination under the microscope in the laboratory on land before they can be accurately identified.

A very nice specimen of a lobster larva, which spends the early part of its life in the open water, carried by the currents, before later metamorphosing into a mini lobster and settling on the reefs.

This morning the outside temperature is 31.5°C and the water surface temperature barely colder at 30.9°C. This makes the seafarer’s work particularly difficult.

Among the instruments we're deploying is the AZFP. This is an acoustic instrument designed to detect mainly meso-macro-zooplankton, i.e. zooplankton organisms larger than 0.2 cm (200µm). The AZFP SN 55180 comprises 4 high-frequency single-beam transducers operating at 200, 455, 769 and 2000 kHz. On this cruise, the AZFP is coupled to TAPS, another acoustic instrument for detecting zooplankton. The 2 instruments, attached together, are lowered to a depth of 200 m, enabling us to establish a vertical profile of organism density. At night, organisms are more concentrated towards the surface.

Launching the TAPS (black tube) and AZFP (white tube); and echogram between the surface and 200m showing in light blue the trace left by each of the organisms observed by the AZFP: the density is greater the closer you are to the surface.

In the micronekton catch of the day

When we woke up this morning, we were surprised to discover a sea of oil. There's less than 1 knot of wind, the surface of the water is shiny and there's not a wrinkle on it - it's a magnificent sight.

The bow of the Antea at the equator in a sea of oil

We're in the waters off the American islands of Howland and Baker, about 30 nautical miles from Baker. So, there are a few reefs in the vicinity, and we are indeed seeing some reef species in our catches. They've been extremely rare so far, no doubt due to the absence of islands and reefs on our route since we left. Many inshore and reef species lay their eggs in open water, drifting with the currents and ending up offshore where they develop into larvae and juveniles. While many end up in the stomachs of predators such as tuna, some will eventually metamorphose into a form resembling an adult and return to the reefs to settle and lead their adult lives.

A 5cm juvenile surgeonfish beginning to acquire color, a sign that it won't be long before it settles on the reef; a 3cm lobster larva (without antennae) that looks just like an adult.

A strange deep-sea pink fish

The micronekton team, crew members and scientists

Station 13 was supposed to be our last sampling station, but unfortunately the wind changed this morning. Since we were on the equator, we've had the wind at our backs, which made navigation pleasant and pushed the boat along, but now we've got a headwind, blowing from the west. This has considerably changed our top speed, and while we'd hoped to make 9.5 knots with the wind at our backs to get back to Tarawa, now with this headwind and the engines pushing hard we're barely making 8 knots. The journey will therefore be much longer to reach Tarawa on October 18. As the stopover is already scheduled, with refuelling and crew changes, we can't delay our arrival in Tarawa. We therefore decided to cancel this sampling station and set off immediately.

Sunset

Some repair on the micronekton trawl

We continue along the equator until we reach the date line at longitude 180. It's not so often that we pass over this symbolic point of latitude 0 and longitude 180, the frontier of both the god Chronos, master of time, and Neptune, god of the seas. Pauline, our on-board artist, has created a special sign for us, and we take this opportunity to take a group photo with the scientists and seafarers.

After the 180, the boat turns off and heads north-west towards Tarawa, which we should reach in 2 days' time, where the second team of scientists is waiting to replace us for leg 2, which will leave Tarawa and continue on to Kavieng in Papua New Guinea, via Nauru and the Federated States of Micronesia.

Team 1 of the Warmalis3 cruise.

We spent yesterday making very slow progress towards the island of Tarawa, with a headwind of over 20 knots and a slightly choppy sea. The captain has set the pace so as to arrive on the morning of October 19 in front of the pass of Tarawa lagoon, at the point where the pilot is due to come aboard to guide the boat alongside. Our last night on board was very hectic because of the bad weather, and there's a certain excitement before the stopover, which is going to be short for the crew to refuel, and for the group of scientists a certain eagerness to be able to set foot on land and return home after several weeks at sea, but also to pass on the baton to colleagues. Unfortunately, we know that we won't have much time to do the handover, as our plane to Fiji takes off in the late morning and the next one is only 4 days later, so we mustn't miss it.

At 6 o'clock this morning, the bridge officers and chief engineer are all on the bridge and we're at the rendezvous point, but the sea is rough with wind and rain. Over the radio we're told that the pilot is waiting for daylight and for the weather to improve, but there's little hope of it calming down. Finally, we are allowed to enter the lagoon slowly and the pilot boat waits for us a little further out; the pilot won't climb aboard, as the manoeuvre is too dangerous in the waves. We follow the pilot boat to an anchorage, but conditions are not favourable for docking. We watch anxiously as the time goes by and our chances of catching our plane dwindle, let alone making the handover with our colleagues.

Finally, permission is given to come alongside, but the captain feels that with the necessary manoeuvres, it will be quicker for the scientists to board the pilot boat and take us to the harbour, where a cab is waiting. A ladder is set up over the side and we have to descend 2-3 meters to reach the pilot boat below, which is moving furiously. Every precaution is taken, and with a little adrenalin everyone manages to get into the pilot boat with their luggage. The quay is 2 km away and we have to pair up with other boats and pass luggage and personnel through 3 other boats before reaching the quay. Some of the replacement crew are there, we're glad to see each other and take 2 minutes to explain a few important points before jumping on the mini bus. The city is flooded with the recent rains and progress is very slow between the huge puddles and potholes, not to mention a stop to put oil in the engine.

The disembarking team finally arrives 5 minutes after the check-in deadline, and only 3 of us who laboriously managed to check in online the day before on the boat are allowed to board the plane. 6 of us remain on the tarmac. With no contact and no means of communication, we eventually found some kind and extremely friendly people who helped us find a hotel and take us there, which is no easy task in Tarawa when you're caught off guard. It took all day, and the responsiveness of our colleagues in New Caledonia and France, to find us new plane tickets and organize our return home.

We finally managed to leave Tarawa for Nauru the next day, several hours late due to a technical problem with the plane. In Nauru, Jonas, who had arrived home, left us and our next plane was waiting to take us to Nandi in Fiji, where we arrived in the middle of the night. The next morning, we left Jeremie in Fiji, who took the time to do a little sightseeing before heading back to France, and Lui caught a plane to Apia, Samoa to return home. For the last 4 of the team, we're off to Auckland, New Zealand, where we'll have to spend another night before finally reaching Nouméa on Sunday, October 22.

Our entry into Tarawa Lagoon

The team disembarking in the pilotboat

In our hotel in Tarawa under heavy rain

For the past 2 days, a major depression has been battering Tarawa, causing widespread flooding on the island. After talking to the local’s people, it seems they have never experienced similar wind and rain.

The Antea was originally scheduled to dock on the October 19 at around 6:30 am. This would have allowed Team 1 to hand over to Team 2 before heading serenely for the airport. Unfortunately, weather conditions were so bad (20 knots, gusting to 35), Antea was unable to reach the quay.

She had to remain at anchor, and the Leg 1 team had to be brought ashore in a small a small boat, to avoid arriving too late at the airport. Part of the leg 2 team was waiting on the quay, for the fastest transfer in history. They found out later that only 3 people had managed to their plane. Later in the day, the Antea was able to return to the quay leg 2 to board and the entire on-board team to get busy to refuel and load supplies...

There was swell and strong gusts of wind. No sooner had we on board, we had to return to the anchorage, as the conditions didn't allow us to stay safely alongside. Hawsers, mooring lines and the cutter broke. The captain decided to return to the anchorage and wait for the weather to improve before completing the refuelling. Once at anchor, the Leg 2 scientists were able to visit the boat meet the crew and take possession of their quarters for the next three weeks. Some of us were a little seasick...

The leg2 team is made up of 9 scientists: Vonklauss from Papua New Guinea, Anne and Sarah from France, and Laure, Élodie, Céline, Marion, Amandine and Christophe (our mission leader) from New Caledonia.It's a very feminine team.

We woke up after our first night at anchor. The weather is still not good, it's still raining but the wind is easing slightly. We're waiting to hear from the captain whether we'll be able to make it to the quay. A few hours later, we learn that the Antea is still not authorized to dock, weather conditions not permitting.

So we take the opportunity to have a meeting with Rémi, the first mate, on the safety instructions and rules to be observed on board the Antea. We practice donning our survival suits and decide to spice things up with a little speed contest. Marion won the contest hands down in 42'70 sec, which is a very good time! BRAVO to her.

Figure 1. Fitting the survival suit

Following this training session, we take advantage of the fact that the boat isn't moving too much to prepare for the next analyses. Marion, Elodie and Sarah are busy in the laboratory, identifying the tubes that will receive future samples for environmental DNA analysis. Amandine gets her bearings, organizes her work area in the filtration laboratory and checks the dissolved oxygen sampling equipment with Céline. As for Laure, Anne, Christophe and Vonklauss, they have started the TDR* to test their operation.

*Temperature Depth Recorder = probe that records temperature at different depths in the water column.

Figure 2. Marion, Elodie and Sarah are preparing tubes for environmental DNA samples.

Figure 3. TDR probes which will be immersed in the water column to record temperature at different depths.

With the weather having calmed down, we were able to approach the quay to replenish our supplies of fuel, water, and provisions.

Docking such a large vessel required the mobilization of all the sailors for the necessary maneuvers.

Jean, Mylène, Vincent, and Stephane were stationed at the bow of the ship to raise the anchor and launch the heaving line (a line with a weight attached to the ropes) to the dockworker once we neared the quay. They executed these maneuvers under scorching sun.

Once the ship was properly moored at the quay, and the gangway was lowered, we could start loading water, refueling, and stocking provisions. Unfortunately, Tarawa being a very small island with no local production meant that we couldn't obtain any vegetables or fruits. As for the refueling, it occurred in multiple stages. Initially, three tanker trucks came to resupply the Antea, and this operation took several hours, extending into the night, with the last truck having to transfer the next day.

Furthermore, in Tarawa, it's impossible to navigate the passage without a pilot, and they cease operation after 5:30 PM.

As a result, the departure had to be postponed to Sunday. Therefore, sailors and scientists took advantage of this delayed departure to disembark and enjoy a moment of relaxation.

Figure 1. Jean, Vincent, and Stéphane at the front of the boat, hoisting the anchor.

Figure 2. Mylène and Stéphane bringing the hawsers onboard.

Figure 3. The Antea docking.

Figure 4. The Antea at the quay, awaiting refueling and food replenishment.

That's it, we're leaving Tarawa!

The Republic of Kiribati comprises three large groups of islands widely geographically spaced: Phoenix Islands, Line Islands, and Gilbert Islands on which Tarawa, the capital is located. Let's talk about Tarawa! We spent 6 nights at Betio Lodge, on the south side of Betio Island. Betio is one of the islands of the coral atoll of Tarawa.

Kiribati's geographical location is astonishing: the country stretches across both the northern and the southern hemispheres, as well as on both sides of the midnight meridian. The country is one of the world's smallest countries in terms of land surface area but one of the biggest considering its sea surface. Already, we start with something complicated... Over 60,000 people live on an area of 31 km2 with a peak height of 3m, and that's what it felt like: a lot of people in a small space, a lot of plastic waste, and few prospects for change. This lack of space has a direct impact on the inhabitants' living conditions: unsanitary streets, absence of agriculture and livestock. Therefore, food dependency and climatic vulnerability are the island's major problems. The primary source of revenue for the State is fishing licenses allocated to the tuna industry.

Figure 1. Example of a polluted area on Tarawa Island

Figure 2. Purse seiner and mother ship (=a vessel used to support fishing operations at sea, notably by storing and transporting fish catches from smaller fishing boats).

Let’s talk about History: during WWII, the Japanese army invaded the atoll where they built a military base whose position was strategic in the conflict against the United States. Tanks still standing along the coast testifies of this occupation. Most of the beaches are not recommended for swimming due to the anti-personnel mines still in the sand and not defused. The Japanese also built the main causeway that crosses the entire atoll, which is only a few hundred metres wide, so it’s possible to see the coastline on either side of this single road. This road gives a strong feeling of oppression.

Figure 3. Ruins from the Second World War

Despite this feeling which affected us all, the island is surrounded by turquoise waters and a magnificent lagoon. We went to visit the north of the island where we spent the day. We were warmly welcomed for lunch, despite their surprise of seeing tourists! On the way back, we had to take a boat, as the stretch we walked on the way in, was inaccessible due to high tide. After waiting for our cab, we were informed that the bridge we had crossed on the outward journey had been damaged and that our cab could no longer pass. It should be noted that this bridge was built by the U.S.A in 1945, and is the only access to the island. We had to walk across the bridge to get our cab which was waiting for us on the other side.

Figure 4. North of Tarawa

We left Tarawa yesterday afternoon, and we're heading for the first station of leg 2, which corresponds to station 13 initially scheduled in the sampling plan of the leg 1 team (see the blog of 23-10-2023 Station 13 - Phantom). This station is located at the equator, at 178°W, at the transition between two distinct zones of the Pacific: the upwelling to the east, where cold, salty and biologically more productive waters upwell from below, and the warm pool to the west, where surface waters are much warmer (see Figure 1), fresher and less productive in terms of microalgae, while it is in this western part that the most important skipjack fishing zone of the Pacific is located. One of the challenges of this campaign is to understand this phenomenon and the ecosystem transition between the eastern upwelling zone and the western Pacific warm pool.

Figure1. Map of mean surface temperatures in the Pacific with surface currents, illustrating the cold areas of the equatorial upwelling to the east and the warm waters of the warm pool. Station 13 is represented by the black dot at the transition zone between these 2 areas.

We therefore have 3 days to transit to that point, and we're using the time to prepare for future operations.

This morning we started the day with a little muscle-strengthening session with our "coach Sarah". It was raining so we moved into the PC science room so that everyone could do their exercises. The program for this session included sheathing, sit-ups, chairs and push-ups.

Figure2. Workout

Later in the afternoon, Christophe, our mission leader, gave us a general presentation of the objectives of the WARMALIS campaigns, and more specifically of this WARMALIS 3 mission. Sarah, a PhD student from Toulouse, then introduced us to the SEAPODYM modeling tool, which allows to make projections of tuna distribution and also the tuna's main prey: the micronekton.

Figure 3. Christophe’s presentation

Figure 3. Sarah’s presentation

As for the sailors, they are always active during this transit. They use this time to carry out maintenance operations, such as filleting (net repair), fountain tapping (= holes in the deck into which a ring is screwed to hold the measuring and sampling equipment). We'd also like to thank them for all the help they give us to improve the quality of life on board.

Figure 4. Fountain tapping

We're starting our second day in transit! Late tomorrow afternoon, we'll reach the equator, where station 13 is located, to start collecting samples.

During our transit, we take advantage of this time to continue our presentations of each other's disciplines. Elodie gives us a presentation on morphological taxonomy and takes the opportunity to define the term micronekton for us. We look at photos of interesting specimens, she shows us the important criteria for identifications and insists on handling these specimens with care, as all external morphological details are important for species identification.

Figure 1. Elodie presenting her work

Then, it's Laure and Anne's turn. They remind us of the basics of acoustics and inform us about the acoustic data we'll be collecting and the different devices we'll be using during the campaign.

Figure 2. On the left, Laure and on the right, Anne, both presenting the acoustics.

The final preparations of material are completed, with Marion and Sarah finalizing the annotation of the tubes. We are also fine-tuning the distribution of water samples to maximize our efficiency on collection day. In the late afternoon, a fire alarm sounded, prompting a drill. The scientists gathered on the quarterdeck, while the sailors donned their firefighting gear.

Figure 3. Fire drill (Rémi explaining the scenario, Gwen and Delphine helping the firefighters get dressed, Alex and Mathieu transformed into firefighters).

And to round off this day of transit, our "coach Sarah" gave us another yoga session.

We're all looking forward to tomorrow when we'll arrive at Station 13 and start sampling.

Today is the 25th of October 3:23pm local time (3:23am UTC), the ship slowed down as it approached Station 13. This marks the first station of the leg 2 team and there's excitement in the air!

After all the ups and downs that caused a significant delay in our departure from Tarawa and three days of transit, everyone was looking forward to this moment.

We rehearsed our procedures, ensured our equipment was in order, and coordinated our operations, we are ready to go.

At each station, a sequence of 7 operations is executed using various equipments.

Céline is the one who kicks off the proceedings.

Celine is our onboard instrumentalist. She is responsible for starting and monitoring the acquisition of the CTD rosette and all its associated sensors (temperature, conductivity, pressure, oxygen, light, fluorescence, turbidity, etc…). She starts and configures the connexion between the various instruments that require real-time data acquisition while they're deployed using the electrocarrier cable. This cable serves as the communication link between the ship's bridge, the science laboratory, and the sampling devices during deployment, allowing us to instantly visualize the collected data on a computer screen. Celine also manages the data acquisition from the Mutinet, which is used in conjunction with a CTD sensor (measuring Conductivity, Temperature, and Depth). The multinet is a sampling equipment deploying 5 nets to collect zooplankton at 5 different depths. Lastly, Celine is in charge of collecting the dissolved oxygen samples from the CTD.

Figure 1. Céline recording data during the descent of the CTD-Rosette.

The first operation during station 13 is the immersion of the rosette. This sampling gear is composed of 12 Niskin bottles attached to a metallic structure linked to the electrocarrier cable that allows us to close the bottles at specific depths. We lower the rosette to a depth of 200 meters and collect water samples at pre-determined depths as it ascends. Our samples were acquired from depths of 199, 152, 125, 110, 96, 70, 49, 20, and 5 meters.

Figure 2. Rosette’s presentation and its sensors

Once the rosette back onboard, Amandine, our filtration manager, along with Sarah, Marion, and Vonklauss, the samplers, gather around the structure to collect the water needed for chlorophyll filtrations done in the wet lab. It is the first time that the 3 of them participate to a scientific survey of that kind. During this first operation, Amandine, Christophe and Elodie guide them through the sampling procedure, explaining them the important details of water sampling.

Figure 3. Sarah and Amandine sampling water from Niskin bottles.

For our first station, we successfully carried out all the intended procedures. However, we ran a little behind schedule and we still need to improve the succession of the operations. Next stations should be quicker!

End of the station Thursday the 26th of october 2023, 3:00am local time! Time to go to bed!

The last scientists in bed woke up at around 9 a.m. this morning.

Usually, everyone lives their own lives on board until we reach the next station. But today, our mission leader Christophe wanted us to debrief the previous day's station, to identify areas for improvement.

At 16:00 local time, we arrived at station 14, our second sampling site. This station is special because it is situated at the intersection of two imaginary lines: the equator (latitude 0) and the anti-meridian at 180° longitude, directly opposite the Greenwich meridian. This meridian, marking the boundary between longitudes 180 East and 180 West, corresponds to the date-change line. It indicates the point at which it is necessary to change the date when crossing it. Crossing this precise point in the middle of the Pacific remains a rare event.

To begin the station, the samplers collect the water and place the samples in the wet lab with the 2 CTD rosettes up.

It's Amandine and Sarah's turn to carry out the seawater filtrations. Numerous analyses are carried out on the water we collect using the rosette. The water is taken and placed in small vials, which we freeze for analysis of nutrient salts once back on land. Nutrient salts are essential minerals dissolved in seawater, which are necessary for the growth and development of marine organisms such as algae, aquatic plants and marine animals. They play a crucial role in the growth and survival of marine organisms. Another part of the water is filtered to recover phytoplankton, and we are particularly interested in chlorophyll. Chlorophyll captures sunlight and transforms carbon dioxide (CO2) into oxygen (O2) and organic matter. In parallel, incubations are carried out on the aft deck of the boat (for 24 hours), to measure phytoplankton biomass and photosynthetic activity.

Figure 1. Amandine in the vessel’s filtration laboratory

We'd also like to introduce you to our venerable, exceptional cruise leader Christophe. You'll notice the perfect harmony of colors between the outfit and the work equipment (photo in support!). It's a source of inspiration for us all, in all humility of course!

Figure 2. On the left, the cruise leader filling in the station form; on the right, the cruise leader matching the station form!

This morning, we had a problem with the acquisition of navigation parameters, which is a major parameter on the boat, in particular for the quality of measurements from instruments such as the fishfinder, the sounder which calculates currents on the boat, etc. The boat's navigation system, which distributes position information, called CINNA, stopped working this morning.

So, at 8:30 am (October 27) local time (8:30 pm UTC on October 26), the boat's navigation system which distributes position information, known as CINNA, stopped without us understanding why. This navigation system recovers all the data from the boat's navigation sensors (three GPS, 2 attitude computers which give the boat's heave, pitch and roll), the AIS system, and the 2 radars). CINNA then distributes "integrated" navigation to all on-board tools for geo-referencing data, and in particular to scientific instruments such as the Acoustic Doppler Current Profiler (ADCP, a screenshot of which can be seen here).

This instrument under the ship's hull measures ocean currents relative to the ship over a depth of ~800m beneath the ship. In order to obtain an absolute current measurement, it needs to know the ship's speed precisely in order to deduce ocean currents by difference. Without CINNA navigation data, it is no longer possible to know absolute currents. Simon, our electronic engineer (see photo), has been busy solving the problem since this morning, in liaison with GENAVIR's electronics engineers in Brest. The problem was solved at the end of the afternoon by remote intervention on the onboard computers from Brest.

After retrospective analysis of the data, here's how the problem appears on the east-west currents. On the following figure showing the eastward current (in red/yellow, in m/s) and westward current (in blue, in m/s), we can see the structure of the currents over the first 800 meters as we move from east, from the dateline, to west, towards the next stations. At around 179°E, a "blue" current bar appears across the entire vertical, indicating false data. This bar corresponds to the moment when navigation has stalled, become false, and consequently produced false absolute currents since, to obtain these currents, we have to remove the effect of navigation from the data of the ADCP instrument which moves with the boat. For more than 1 degree of longitude of our displacement along the equator, which corresponds to around 7-8 hours of navigation for 60 nautical miles or 111km (at our boat speed of 8 knots or 8 nautical miles per hour, or approximately 15 km/h), the data being totally absent, the current cannot be calculated, which is transcribed by a white zone on the graph.

With navigation back on track, currents can once again be calculated. These east-west currents are complex. Here, at the equator, they are "laminated" vertically, with alternating eastward currents at the surface at around 0.3 m/s, followed by a very thin layer of westward currents at around 100 m, alternating with a thicker eastward layer known as the equatorial undercurrent, followed vertically by a westward current known as the equatorial intermediate current, followed, albeit less markedly, by a layer of reverse currents at around 800 m/s. These are not new structures, but they are noticeable features of ocean circulation at the equator.

First trip at sea for Sarah

Sincerely toulousaine and enthusiastic supporter of the Stade toulousain, Sarah gets onboard for the first time and by her side, we watch (especially the captain) the Rugby world cup. Sport, she watches it on TV but above all she likes to work out! That’s why, she’s our Coach Sarah! Well, more seriously, who is Sarah?

Sarah started a PHD (CLS Toulouse and OBS Brest – Physics and spatial oceanography Lab) about micronekton modulization related to biogeochemical cycles. These cycles show how micronekton captures the carbon in the ocean. We know that micronecton migrates vertically everyday: during the day, it stays in the depths of the ocean to avoid predators and then it swims back up to the surface at night to feed on zooplankton. The micronekton exports carbon towards the depths thanks to this migration and its diet.

That’s why Sarah is with us onboard. On shore, usually she works on computers for her thesis, but it’s important to see and know the species she works on. Therefore, she got onboard to discover the cute big family of micronekton, the biology of species and how it’s captured.

Just like Robin Hood, Sarah has more than one string on her bow. During her Engineering school, she studied chemistry, so naturally she helps Amandine to collect and sample chlorophyll and nutritive salts. Just a reminder, chlorophyll is all the microalgae (phytoplankton) that are the base of the food chain, and the nutritive salts are chemical elements influencing the phytoplankton’s growth.

It’s with the CTD that Amandine and Sarah collect all these water samples. Once it’s done, they filter the water at the dry lab and keep the filters for later analysis back on land.

After chemistry, let’s go back to micronekton! During hauling the micronekton trawl, she runs at the bridge to ask the captain all the info concerning the set, then she runs back to the wet lab to help Elodie and Laure for sorting out the miraculous micronekton big jag! After all this work, it’s finally time to have some deserved rest and crawl into her bed.

So Sarah, what are your first impressions? I love the sampling experiments and it’s really cool to finally see what I modalize on computers!

This Sunday, a day always a bit special on board, begins very early for the most motivated among us. Indeed, the Rugby World Cup final is broadcast live in the mess, and due to the time difference, the kickoff is at 7 a.m. Once the connection is set up and installed by Simon, our onboard electronics expert, the most fervent fans, whether scientists or sailors, gather around the traditional Sunday morning pastries to watch the match.

Figure 1. Our athletes are all very focused on the game.

Everyone then gathers together at 11 a.m. for lunch. The kitchen team, Delphine and Gwen, have once again outdone themselves to provide us with an excellent meal. We honor it by wearing the Sunday 'bula shirts' (floral shirts), following in the tradition of the leg 1 team. Everyone joins in the spirit!

Figure 2. A wide variety of Pacific patterns for lunch.

We arrive at Station 17 at 4:15 p.m. The procedures progress as usual. During the biological samplings carried out with a net for zooplankton and micronecton, Marion is in charge of collecting DNA samples. A true navigation enthusiast, Marion is our technician in the team, working at the CPS in Nouméa in the tuna fishing section. She has significant sea experience, having embarked numerous times on tagging and biological sampling campaigns related to tuna. However, despite her familiarity with trawling procedures and the marine environment in general, this is her first oceanographic campaign of this kind.

Marion feels completely at home on board and takes part in several samplings: CTD samples, oxygen measurement, and above all... DNA! For these DNA collections, Marion uses small perforated spheres containing gauze. These spheres are attached to the zooplankton and micronecton nets during fishing. Once the nets are hauled on board, Marion retrieves the spheres, being careful not to touch anything else, removes the gauze pieces, and then places them in tubes with ethanol to preserve the DNA in the freezer before analysis back on land. This procedure is delicate as it requires disinfecting all surfaces in contact with the spheres and extreme care when handling them.

Through this sampling, we hope to detect the DNA of all organisms that passed through the nets, aiming to compare these results with the morphological identifications made on the specimens contained in the nets. The station finally concludes under the full moon, once all the procedures are completed.

Figure 3: Marion preparing the metaprobes (left), the trawl team of the day, and metaprobe recovery in the "trawl butt" (middle), Marion taking water samples from the rosette and carrying out the oxygen sampling with Céline in the wet laboratory (right).

Acoustics, still fantastic!

A new week begins, the second one for the leg 2 team. As we move further towards the West Pacific, we are noticing changes in the acquired data, particularly in the acoustic data gathered using the three devices available for the 2nd leg.

As explained during station 3, the acquisition of acoustic data is continuous with the EK80 sonar, positioned beneath the boat's hull. This device emits waves into the water that are reflected by all organisms present beneath the boat. We measure these reflected waves, which indicate the locations of organisms within the water. The acquisition is continuous with the vertical EK80 sonar, which emits five waves every 3-4 seconds at 18, 38, 70, 120, and 200 kHz. Each wave has a different acquisition depth: the lower the frequency, the farther it can detect (1500 m at 18 kHz and 200 m at 200 kHz).

With the EK80 echosounder, we can observe the vertical distribution of organisms and in particular their migration behaviour from the depths to the surface. Every evening, we wait until vertical migration is complete and the organisms have settled into their preferred depth for the night, before starting the biological measurements.

In this part of the Pacific, known as the warmpool, migration often stops before the surface. At today's one we even observed an unusual phenomenon: at the same time, a downward migration, visible only at frequencies 120 and 200 kHz, from 20 m to 100 m (figure 1 right), while we see a classical upward movement from 400 m to 150 m on frequencies 18, 38, 70 kHz (figure 1 left).

Figure 1. Echograms at 38 kHz (left, on 800 m high) and at 200 kHz (right, on 150 m high) showing the two types of migrations at the start of station 17.

Organisms are not detected in the same way at all frequencies, because depending on their size, shape and constitution, they each have a "frequency signature", and it's the multi-frequency approach that helps us to differentiate between, for example, crustaceans and fish with gaseous swim bladders: crustaceans give echoes that increase with frequency (strongest on the EK80 at 120 and 200 kHz) and mesopelagic fish with a gas bladder can have a very strong echo at 18 or 38 kHz depending on the size of their bladder.

Acoustic profiles are acquired on station using zooplankton profilers: TAPS (420 kHz at 3 MHz), which can withstand 200 m of immersion and targets micro/meso-zooplankton, and AZFP (200 kHz at 2 MHz), which can withstand 600 m of immersion and targets meso/macro-zooplankton (shown in station 11). This equipment is coupled to a pressure sensor linked to the boat by the electro-support cable, so that the immersion depth of the devices is known in real time.

The acoustic properties of crustaceans in particular are exploited using data from multi-frequency profilers such as TAPS, which operates at 5 frequencies: 420, 769, 1100, 1850 and 3000 kHz. These frequencies were chosen to give priority to the detection of organisms such as copepods. Knowledge of their frequency signature at the frequencies used, combined with measurements, enable us to reconstruct zooplankton volume profiles as a function of depth for various size classes. The profile is also related to environmental parameters such as temperature (figure 2).

Figure 2. TAPS Profiles. On the left, the temperature, and on the right, the acoustic echoes at the 5 frequencies in decibels. On the right graph, the further right a curve is situated, the stronger the echoes, indicating a higher density of organisms.

Laure Barbin and Anne Lebourges-Dhaussy are in charge of acoustics for the Leg 2.

Laure Barbin: after attending engineering school in Toulouse, Laure discovered her understandable passion for acoustics dedicated to the study of marine ecosystems, during her Master 2 at the IRD in Brest, with the LOPS and LEMAR laboratories. She then embarked on a thesis at Sorbonne University, with the ENTROPIE, LEMAR and CPS laboratories, on the study of micronekton on the Pacific scale, as part of the CPS-IRD MICROPAC project, during which the WARMALIS campaigns were carried out. She carries out her work in Nouméa and is taking part in her 3rd WARMALIS campaign. Onboard, she takes care not only of echosounder seeing and profiler data acquisition and recovering of the data but also of the configuration of pressure/temperature sensors that are fixed on the bongo net and on the trawl, and she participates also to the micronekton sorting.

Figure 3. Laure checking data acquisition

Anne Lebourges-Dhaussy : Anne is a research engineer at IRD, co-directs Laure's thesis, and is in charge of IRD's acoustic platform, based at LEMAR in Brest. This group is made up of engineers who embark on numerous campaigns at sea around the world, following IRD's research programs in all the tropical oceans. After completing her PhD in acoustics at the Université Pierre et Marie Curie (now Sorbonne Universités), Anne developed her career around the use of acoustic methods for marine ecosystems, focusing on trophic levels ranging from the smallest zooplankton to the largest fish and micronekton. One of her passions is to search the echograms above for shapes reminiscent of the strangest animals, and to imagine from these unusual but grandiose graphics what will actually be caught in the trawl. She has taken part in numerous sea campaigns, including 2 WARMALIS, and is currently chair-woman of the international WGFAST group (ICES Working Group on Fisheries Acoustics, Science and Technology).

Figure 4. Anne and Alex fixing the bioluminescence sensor.

Today is October 31, 2023, and we're about to start up station number 19. The science team meets in the scientific room 1 hour before the start of operations, to celebrate this special day. And it's here that we discover some hidden talents, I'll let you judge for yourself.

Allow me to introduce you to the hard-working team without whom all these operations could not take place. It's thanks to these people that we're able to launch all our equipments. Complex operations requiring special know-how, whether for water sampling, acoustic gear launching or nets for zooplankton and micronekton sampling. We would also like to take this opportunity to thank them.

Figure 1. The deck team, from left to right: Alex, Vincent, Stéphane, Mylène, Jean our bosco (copyright: Alexandre d'Acremont).

And it's in a darker register that the rest of the day unfolded…

As night fell (whoooo), the myctophids ascended from the obscure depths where unfathomable and cruel creatures dwell. In this dark hour (brrrr), we deployed the trawl. On the deck, swept by the cruel elements, daring sailors actively engage in deploying the gear. On the bridge, Rémi and Arnaud, sporting carnivorous smiles, assured gestures, and conquering eyes, release the instrument into the mysterious and icy depths (brrrrBRRR!). The full moon rises… the boat trembles beneath the frightful noise of cables and winches, creaks resound (crack!), the moon disappears behind black clouds heralding some dreadful fate (for the micronekton). Like lost souls, Elodie, Sarah, Laure, Marion, Amandine, Vonklauss wander the passageways like ghosts awaiting the fateful hour.

'Cod-end on board!' shouts the captain with a voice from the grave. The dark water churns, sharks loom, vainly attempting to engulf our meagre bounty.

Hooray, the net is on board! And in one final surge, the trawl regurgitates the micronekton and consigns it to its dark fate in a cold burial (freezer -20°C!).

Presentation of some specimens observed in trawls (Copyright: Elodie Vourey-SPC) :

Figure 2: on the left, Phyllosoma of Palinuridae (Lobster’s larva); on the right, Chiasmodontidae (Snaketooth fishes)

Figure 3: on the left, Chiasmodontidae (Snaketooth fishes); on the right, Neognathophausia ingens (Deep sea shrimp)

Figure 4: on the left, Histioteuthidae (strawberry squid); on the right, Evermannellidae (Sabertooth fishes)

Figure 5: on the left, Sternoptyx sp. (Marine hatchetfishes or deep-sea hatchetfishes); on the right, Thalassenchelys sp. (Larve de poisson serpentiforme)

Figure 6: on the left, Notostomus sp. (Deep sea shrimp); on the right, Malacosteinae (Barbeled dragonfishes)

Figure 7: on the left, Scopelarchidae; on the right, Diretmidae

Today is the first day of November, and we're still at latitude 00°, slowly making our way towards Papua New Guinea, at a rate of 2° westwards per day. Since the start of Leg2, and since the beginning of the campaign in general, we've seen an evolution in our quest for micronekton. Indeed, the surface trawl is getting poorer, while the 500 m trawl stays as complete as ever, without being any less interesting.

Figure 1 : The micronekton trawl

Every day we have some very nice specimens, make of our talented taxonomist Elodie very happy ("Ohlala un Neognathophausia ingens c'est très très beau"). Here are the different steps of a typical station for Elodie... When it's time to trawl, Elodie goes up to the bridge with Sarah to note down the fishing information dictated by Arnaud, our captain. Before the trawl is finished, she goes down to the deck to put on her helmet and survival vest (always with unbeatable class). She prepares the equipment needed to receive the samples: sieves of various sizes, a large bucket, trays, etc. When the deckhands retrieve the pool codend (quite explicit, but nonetheless very scientific term to define the bottom of the trawl in which the organisms end up as it rises), she collects all the treasures it contains in the big bucket. She empties it into the sieve, discovering the different organisms with amazed eyes, and takes it to the wet lab for sorting. It's at this point that the investigation begins: the specimens are sorted by a dynamic and enthusiastic team (Laure, Sarah, Vonklauss, Marion) and divided into bags by major category: crustaceans (e.g. shrimps of all shapes and sizes), fish (e.g. Myctophidae, small fish with bioluminescent photophores), gelatinous (jellyfish or other strange viscous masses), molluscs, etc. Less common organisms are extracted to be observed and photographed by Elodie. Despite her impressive knowledge of taxonomic classification (groups, families, genera and species) ("Ohlala un Neognathophausia ingens c'est très très beau"), morphological criteria and identification keys, she'll need more tools once back on land to identify them accurately. Only gelatinous are weighed and measured, and the bags resulting from this rough sorting are kept at -20°C in the boat's freezer.

Figure 2: Elodie and THE TEAM during WARMALIS 3

In addition to her talent for identifying micronekton, and her unfailing memory for the unpronounceable Latin names of species, Elodie assists Christophe with the general organization of Leg2. With an important experience in campaigns at sea, she is familiar with the various operations, and her rigor is essential to their successful completion. Despite a persistent seasickness, she continues to embark light-heartedly (or almost), out of a passion for micronekton.

Caledonian resident since 2004, Elodie has been a taxonomist at CPS for 13 years. A large part of her day-to-day work on land consists of studying samples from previous campaigns. She takes back the bags of frozen specimens, and the aim is to identify each specimen as precisely as possible, trying to get right down to the species (which may not be possible if it's too damaged). To do this, she has several tools at her disposal: a large bibliography containing identification keys, precise definitions of morphological criteria, drawings and photos, binocular magnifiers, X-rays to study the skeleton, etc. Elodie has already described a new species of fish and is currently working on the description of two new species found during one of her sea campaigns!

Figure 3: Example of specimens of micronekton from scientific research voyages identified at the SPC laboratory (Copyright: Elodie Vourey).

The afternoon of this Thursday begins with great seriousness, with a presentation by Christophe to the entire scientific team about the functioning of the climate and climate change. This brief refresher in physics is useful for everyone to contextualize our work and this mission within current challenges. Indeed, the study of micronecton in the tropical Pacific contributes to increasing knowledge about the oceans and, in turn, predicting ecosystem variations with climate change.

Figure 1. Christophe sharing his knowledge with us.

Following this interlude, we begin Station 21 at 4 p.m. as in previous days. All operations proceed smoothly. Part of the tasks related to sampling biological organisms during the night involves studying zooplankton. This is the link in the food web situated beneath the micronecton: smaller than the latter, zooplankton serves as food for the micronecton. It consists mainly of small crustaceans, mollusks, gelatinous organisms, and larvae of various species, often too small to be observed with the naked eye.

Christophe and Vonklauss handle the sampling of zooplankton using two different nets: the bongo net and the multinet. The bongo net is a structure with two very fine mesh nets: 100 and 200 micrometers. They filter the water from the surface to a depth of 200 meters. The delicate zooplankton collected in this way is retrieved, placed in containers, and preserved in formalin. Once on land, it will be possible to analyze it using a microscope or dedicated magnification devices to identify the specimens caught, determine their numbers, and classify their species.

Figure 2. Bongo nets on the left. Christophe and Vonklauss collect the zooplankton, place it in containers, and add formalin to preserve it. Here, small shrimps are observed.

Christophe is one of the individuals in charge of zooplankton, alongside Vonklauss. However, this is not his only role. He is also our mission chief, overseeing the organization of Leg 2 with impeccable management. He adjusts the smooth running of operations on a daily basis, in coordination with Arnaud, our Captain. Far from staying out of the manipulations, he participates in sorting the trawl (specializing in labeling for sample storage), takes comprehensive notes during the stations, and monitors data acquisition on currents.

On land, Christophe wears many hats. He is a research director at IRD Nouméa, focusing on research related to climate change and its associated phenomena. He began his scientific career by studying the El Niño phenomenon (a Pacific climate oscillation strongly influencing weather patterns on an interannual scale). His curiosity led him to explore other subjects, such as the study of micronectonic ecosystems in the Pacific in collaboration with Valérie Allain and the CPS. He also delves into researching marine and atmospheric heatwaves, the terrestrial impacts of climate change in Pacific islands, particularly on agriculture and the transmission of local knowledge (CLIPSSA Project). He is also interested in the link between climate and vector-borne diseases (dengue, leptospirosis, Zika, chikungunya). He supervises several doctoral students and is responsible for the coastal sensor network REEFTEMPS as well as being the director of the Aligned Planets Council. His dog's name is Zorglub.

Today, Vonklauss is the star of the blog!

We have the pleasure to have onboard Vonklauss who’s lecturer in Marine Science at the University of Rabaul in Papua New Guinea, and for the first time he participates to an oceanographic cruise.

For a long time Vonklauss has been interested in getting onboard such a cruise, so when Valerie proposed him to get onboard, he was very enthusiastic despite knowing he will be surrounded by French people (poor fella!). Indeed, Vonklauss is the only English speaker onboard but even though he can’t understand French, he’s still very interested in all the operations, and happy with the cruise and his colleagues! For us, it’s a good motivation to speak English amongst us even if sometimes we speak Franglish with a terrific well-known accent! Nevertheless, everybody tries his best and so we have a good team spirit. By the way, Vonklauss also learns some very useful French words like: filet mignon and our cruise leader is mignon (cute).

During the whole cruise, Vonklauss participated in all kind of operations: water samples for Amandine, Zooplankton with Christophe our Chef mignon, and sorting micronekton with Elodie.

Let’s focus on zooplankton because Vonklauss managed these operations with Christophe; the Bongo and the Hydrobios. The Bongo is a net with 2 sizes of mesh (100µmicron et 200µ micron) that goes down to 250 m and comes up vertically to the surface. Vonklauss and Christophe retrieve the 2 collectors for zoo, and usually, they find mini-micro-shrips fighting for their life, but as they are way too strong (survival of the fittest...), the mini-micro-shrimps end up in small containers filled with formalin for the preservation.

After Bongo, they work on the Hydrobios. Hydrobios is another zooplankton collection method that uses 5 different small nets (mesh 100µ micron), but this time the Hydrobios goes deeper and collects sample at different depths.

1. 500m-200m
2. 200m-150m
3. 150m-100m
4. 100m-50m
5. 50m- surface

The winning duo Vonklauss – Christophe does again the same manipulation and transfer the zooplankton from the collectors to the small containers where these small defenceless creatures will be preserved.

Once Vonklauss is done with zooplankton, it’s time to dress up in his micronekton costume and be ready for the 2nd trawling. But before that, in order to get some strengths and face work till dawn, he eats some French baguette with tea. This is a total victory for the Frenchies; Vonklauss has been into French baguette with spread salted butter during the whole cruise! He might open a French bakery in Rabaul …

When he sorts micronekton, he’s very focus and careful, so often he founds nice specimens for Elodie and she always answers him in a very professional way: LOOK Vanklauss, this is INCREDIBLE!

As a conclusion, Vonklauss is more than satisfied and glad to be on this cruise and he’s ready to share his experience with his students. For the Frenchies, it was a real pleasure to have him onboard, and they can’t wait to be Kavieng to discover with him the last step of the cruise.

Today marks our 17th day at sea. And we are taking advantage of the free time before arriving at the station to make a few presentations.

It is Céline and Amandine's turn to show us the instruments they use on board to carry out the various sampling operations.

Céline reveals all the secrets of the probes and the measurements taken in real time. The presentation continues with a guided tour around the rosette, allowing us to see exactly where the probes are located and how they work.

Figure 1: Céline's presentation

Amandine continues with her presentation. She explains the scientific purpose of all the water samples taken with the rosette, and gives us a brief introduction to the analysis techniques that will be carried out once back on land. On the Antea research boat, we mainly carry out sampling and filtration, but we'll have to wait until we're in a laboratory to analyze these samples using specific equipment.

Figure 2: Amandine’s presentation

It's 3.30pm, time to get ready, we arrive at the station, the 23rd in this WARMALIS 3 campaign.

First of all, we'd like to apologize for our silence over the last few days! We weren't able to blog the final moments of the mission, as the weather deteriorated sharply the day after the last station, right up to our arrival in Papua New Guinea. As the boat was notoriously unsuited to bad weather, our editor and several team members were unable to keep the blog up to date.

On this Sunday, November 5, we would like to introduce you to the three people in charge of navigation, who run the boat from the wheelhouse during operations.

The Antea never stops during this campaign, and is constantly on the move, either on the way or on station for sampling. So, there is a watch system, with a rotation of 3 people: the captain, the first mate and the lieutenant.

Let's start with the captain, Arnaud Behoteguy, without whom none of this would be possible. He is the big boss!

Figure 1: Arnaud on the wheelhouse

Arnaud began fishing at a very early age, in the Atlantic and in Ireland, where he worked as a bottom trawler. Curious and interested in scientific aspects, he later joined Genavir as second-in-command, before becoming captain. Passionate, he enjoys his job, meeting people from different backgrounds and the diversity of fields of study during campaigns (biology, geology, oceanography, etc.).

Figure 2: Arnaud at the trawl's controls

On board the Antea, one of his many roles is to ensure operations, while keeping an eye on the boat's surroundings. For example, yesterday, during the night, in the middle of the station, he saw something on the radar, the size of a small boat, approaching the boat, but when he looked outside, there were no lights, so it was impossible to see what it was. He then called in a sailor to help him find and recognize this unidentified object, and, surprise, it was a huge tree trunk that passed just a few meters from the ship. All went well, Arnaud managed the situation and operations at Station 23 were able to continue as normal.

Figure 3: Detecting tree trunks with radar

Now we come to Remi Décaillon, the first mate. He started out as a helmsman in the French Navy at the age of 18. At 25, he attended hydrology school, and sailed on a large number of vessels, including roll-on/roll-off freighters. He also sailed for industrial transport, carrying Ariane 5.

In 2018, he joined Genavir as a lieutenant, sailing mainly on the Thalassa, then the Alis in the Pacific. After a 2-year absence, we welcome him back as second-in-command on the Antea.

Figure 4: Remi with binoculars on the bridge

Keeping watch on the bridge also means knowing how to deal with stowaways, especially when the latter are confusing the weather data, the wind is picking up, the birds “fou” are resting! Remi decides to try blowing the foghorn, but to no avail.

Figure 5: Birds “fou” on the masts

And finally, here's Cyrille Le Laurec, our lieutenant. He also started out as a fisherman, then spent 8 months on board Ferrys, then 8 months on hourglasses, and arrived at Genavir a few years ago.

As you can see, 3 people with a wealth of experience are involved in this campaign, and we're delighted to be working together.

Figure 6: Cyrille making the route on the map

We are on Monday, November 6th, in the morning of the last station. The weather is rainy, and the Antea is starting to experience a slight swell, which is normal as we are approaching Papua New Guinea.

This station is a bit special; it's the final station of the campaign. Everyone is torn between the excitement of finishing the campaign, the satisfaction that everything has gone well, and the sadness that the adventure is coming to an end. As a bonus, shipboard rumors hint at the prospect of an ultra-deep trawl!

For some time now, Elodie, our chief micronecton taxonomist, has wanted to experiment with an ultra-deep trawl at around 1000 meters. This topic has been discussed with Arnaud the captain and our mission leaders, Christophe and Valérie.

And so, the last station arrives. Elodie's excitement convinces the leaders, and she obtains approval for a third trawl at a maximum depth equal to the ship's capacity. Depending on the boat's engine power and the length of the cables that drag the trawl, Arnaud will do his best to reach 1000 meters. However, to respect working hours and not finish the next morning, sacrifices must be made in terms of manipulations. It was not an option to sacrifice the two usual trawls to do the one at 1000 meters. It was decided not to perform the hydrobios, bongo, and AZFP.

The second CTD is back on board, and it's time for trawling. Everyone is looking forward to it! The first two go very well, and then comes the time for the third trawl. We are on schedule. On the bridge, Elodie, Christophe, and Anne watch attentively as Arnaud puts the trawl in the water and begins the descent. In the science PC, Vonklauss and Marion joyfully watch the screen showing the depths of the trawl. On the deck, the rest of the team and the sailors listen as Arnaud announces the depths and monitor the lengths of cable remaining on the reels. We find ourselves back on the bridge, each noting that the trawl has exceeded the usual depths. Then, around 985 meters, we lose the scanmar data (sensor that provides real-time depth information for the trawl). The trawl is probably too far, and the information transmitted by the scanmars no longer reaches the boat. Arnaud continues to release, and we regain the signal at 1028 meters. We are all in awe at this depth. It's exciting, and then we lose the information again. Arnaud decides to stop releasing 41 minutes after the start and decides to start fishing with a cable length of 2123 meters. We don't have the exact depth of the trawl, but we know we will have this data later, thanks to the TDR sensors at the back of the trawl. Then, at 12:51 (UTC), Arnaud decides to start the turn, that is, to start winding the cables to bring up the trawl. And there, a little moment of panic, Arnaud notices a problem with the starboard winch (the winding of the cables is not going well). The on-duty mechanic is then awakened and arrives on the deck to understand and solve the problem as quickly as possible. Tension is at its peak. Indeed, the last recorded depth of the trawl is 1076 meters, and Arnaud does not want the trawl to remain in this position for too long.

Figure 1: Data sent in real time by scanmars

At 13:02 (UTC), the problem is resolved, and the trawl can finally come up slowly. Everyone is curious to discover the treasures from the depths. Elodie is torn between the excitement of finding out if the species composition is different from other depths and the apprehension of having nothing in the trawl due to the extremely weak acoustic signal.

The codend of the trawl arrives, and many are on the deck! Elodie passes the basin to Alex to receive the codend. The codend is lifted forcefully out of the water and placed in the basin. The sailors congratulate themselves for this feat; they clap their hands and are happy to have participated in this adventure.

Figure 2: Sailors happy after hauling up the trawl net on board the boat

The time has come to open the codend of the trawl. Arnaud takes advantage of Cyril's shift change to go down to the deck and also discover the contents. The first observation: there are specimens, phew! It's not empty. Elodie immediately sees two deep-sea fishes that she had never encountered since the beginning of the campaign. She is delighted. This is followed by a dance between sailors and scientists, then team photos before sorting.

Figure 3: Team picture at the end of the third trawl

Figure 4: Arnaud and Elodie, happy with their trawling!

Once these bursts of joy are over, it's time to sort in the wet lab. Elodie discovers crustacean specimens she had never seen before, takes photos, and packages these precious samples awaiting identification upon return to land.

This last station was a success, and Elodie was able to satisfy her curiosity! Now, we're heading to Kavieng for 2 and a half days of transit with a bit of a rock'n'roll weather!

The evening before our arrival in Kavieng on November 8th, we held the end-of-mission gathering on board during the transit. The crew had set up a canvas to shield us from the rain. Seats and benches were arranged around the griddle so that we could enjoy this moment despite the adverse weather conditions. With great emotion, we listened to the speech from our exceptional mission leader, marking the conclusion of the WARMALIS 3 campaign, the last in the WARMALIS series.

The next morning around 8 am on November 9th, under a cloudy sky, we were delighted to catch sight of "land" and the city of Kavieng; the setting was superb. Customs and immigration officials came on board before allowing us to disembark. Everything went smoothly, and we were all granted permission to set foot on land.

But before leaving the ship for good, we organized the laboratories. Some conducted inventories of equipment in both labs, while others finished entering data. Around 3 pm, Vonklauss left to drop off his belongings at his hotel as he was departing the next morning. Some decided to explore Kavieng's market. Once back on the boat, with bags packed and all equipment inventoried and stowed for the return transit, it was time for the science team to contact the hotel on the tiny island of Nusa, located opposite the quay where the Antea was moored. We needed a small boat to transport us to this beautiful island, which would be our residence for the next 3 days.

With luggage in hand and more than pleased, we arrived on this island where the hotel exceeded all our expectations! Its style, very typical of Papua New Guinea's dwellings, left us in awe. This sense of amazement continued as we discovered our bungalows and moved on to cocktails and dinner. We started the meal with a delicious soup, followed by a buffet featuring a variety of vegetables (which we had sorely missed during leg2), curry crab, spicy chicken patties, and more. In short, it was a burst of flavors, pure bliss! Most of the crew joined us later for a final drink before setting sail again the next afternoon. They would arrive in Noumea between the 19th and 20th, and we would meet them then to unload all the equipment and samples.

Figure 1: Nusa Island Retreat

So, with great pleasure, we enjoyed the island of Nusa, strolls, Kavieng's market, local crafts, and, of course, the fantastic restaurant! We returned to Noumea on the evening of the 12th.

Figure 2: Kavieng market

Thank you very much, Ko rabwa, Tankyu tumas!

Figure 3: WARMALIS 3 leg 2 scientific team (top left to right: Amandine, Christophe, Vonklauss, Marion, Laure; bottom left to right: Sarah, Anne, Elodie and Céline)

Arrival of the boat in Noumea

It has now been a week since most of the scientists returned to Noumea, and as for the Antea, it arrived yesterday, on Sunday, November 19th, in the afternoon.

We are all scheduled to gather at the boat on Monday, November 20th, at 8 am, for the demobilization, which involves the retrieval of all our equipment and samples.

Figure 1: Unloading equipment (copyright: Nicolas Job)

We need to make several trips by truck to transport the samples as well as all this equipment to the IRD and CPS offices in Noumea.

Figure 2: Transferring samples from the vessel's freezers to the SPC freezers (copyright: Nicolas Job)

This mission has been a success, with 25 stations sampled along the equator, representing a significant number of operations including:

• 48 CTD-Rosettes for vertical probe profiles and water sampling
• 24 hydrobios-multinets to collect zooplankton
• 16 bongos to collect zooplankton
• 52 trawls to collect micronecton, including 1 deep trawl at 1176m, representing thousands of specimens
• Beautiful acoustic recordings due to the favorable weather conditions along the equator...

It has also been a human success thanks to the atmosphere within the scientific teams and the work of the sailors. We all return to the office with a little twinge at the heart, as is often the case after an excellent mission. But the work on the Warmalis missions has only just begun, and in the years to come we'll be spending many hours in the laboratory analyzing samples and in front of computers processing and compiling data.

Finally, thank you for following us throughout this blog!

Yesterday was very busy with all the visitors but today is also going to be very intense with a lot of work ahead of us to uninstall everything. The crew and the scientists will clean and pack all the equipment from our campaign to give space to the next scientific team composed of divers. There is heavy work conducted by the crew with the removal of one of the winches and the micronecton net. Suddenly the deck seems much spacious. We disconnect and pack all the cables from the movable acoustic equipment and the filtration system from the wet lab is stored on land in a dock waiting for the French Polynesia campaigns in a month time. Everything is labelled and packed in boxes and some boxes are loaded in a container that is going back to Noumea. We were lucky with the weather until the end as a storm with heavy rain stops the work for a while.

Disassembling the acoustic equipment from the movable pole

The deck with boxes that will be shipped back to France, Noumea or French Polynesia

Under shelter in the container, waiting for the rain to stop

This morning, we had the visit of several classes on board, terminals S and 3ème. We had 5 activities in which they toured to explain our work on board. One activity was on physical instruments and phytoplankton, a workshop on micronecton, a workshop on acoustics, another on the pelagic ecosystem and a last one at the bridge where the second captain and the lieutenant explained the operation of the boat. The children seemed to appreciate. This afternoon, it was the turn of the local authorities to come and visit the boat, customary minister, staff of the agriculture and fisheries department, representative of the vice-rectorate, agents of the environment department, head of Wallis radio, representative of the Chamber of Commerce, they too seemed interested by our work.

Martine and Celine explaining the rosette (top left), Aurore presenting pelagic ecosystem species (top right), Elodie showing some organism caught during the trip (bottom left) and Gildas showing acoustic (bottom right)

For this last day at sea, the wind has finally slightly decrease. We decided to conduct a sampling station on the windward side of Wallis that we have not explored yet. The station goes well and we even see a hammerhead shark, curious, following at the back of the boat. The trawl is coming back with organisms that we have not yet collected, and even a fish that we have never seen. Around 2pm, we make our way to the lagoon to find the wharf from which we left two weeks ago now. To close a beautiful mission that will have unfolded, certainly in mild weather conditions, but always in a good mood, we make an end of trip barbecue on the deck at night at the wharf.

Launching of the zooplankton net by crew members during the last sampling station

Group picture

Scientific team

After 2 trawls on the slopes of Lala Rock that allowed us to catch interesting fish, we decide to steam southward toward the deep trench at more than 4000 m depth that we tried to explore a few days ago. We steam sideways with a wind stronger than 25 knots and it is very uncomfortable. Around 8 am, the captain decides to change route. The sea is too rough to work. Once more, we have to seek shelter on the western side of Wallis island.
We decide to look for the fish aggregating devices (FAD) that are anchored around the island around 1000m depth. They are visible at the surface by a line of orange buoys. FADs are mimicking floating logs that tend to attract fish. Fishermen fishing around FADs can hope catching more easily top predators such as tuna, mahi mahi, wahoo. We cannot find the FAD that is supposed to be located in the south of the area, but we manage to find the FAD in the north-west. The acoustic indicate no activity around this FAD and we move toward the northern FAD. We observe some birds and some small fish around the FAD and patches visible on the acoustic sounder indicate there are fish around.

A) a fish of the  family Melamphaidae, B) a fish Cyclothone, C) an unidentified shrimp that seem to have a helmet on its head

The surface buoys of the fish aggregating device (FAD) in the north of Wallis Island

This morning we left the quiet waters behind Wallis to join a seamount to the east, the Lalarock. This seamount is actually an assemblage of several peaks that rise to about twenty meters below the surface; the depth goes from about 3000 meters to 20 meters in a few kilometers, a real mountain under the sea. We know through the literature that seamounts are often conducive to the aggregation of all parts of the food web, so we wanted to confirm it for that one. After 6 hours of transit in a rough sea, we arrive by the south of the mount. The objective is to make a first radial to better understand the complex bathymetry of the mount and to see if the rate of aggregation is different on the leeward slope and on the wind slope. A whale group surfaces right next to the boat, and the acoustic signal is very strong on the slopes. This site seems to be a gathering place for marine life. We also do shoots of Sippican XBT around the mount, this probe is pulled from the boat, goes down to 750 meters and transmits us live a vertical profile of temperature. It will also help to better understand the organization of water masses and currents around the mountain.

Elodie taking the pictures below in the wet lab

Some specimens from yesterday’s net: decapoda shrimp (A and C), a juvenile holocentridae (or squirrelfish, B), ), a juvenile Pomacanthidae (or angelfish, D) and an amphipode (E)

Martine doing a Sippican shoot and the corresponding vertical profile of temperature

Echogram of the Lalarock peaks. Three very different shapes can be seen: the one pointed by the finger with a crater-shaped and culminating at 400 meters, the one on the top right with a summit at 20 meters with a high density of organisms on the left and the one at the bottom showing a flat and wider top.

We finished the sampling station yesterday around 9pm and we decided to steam eastward to conduct a sampling station above a trench deeper than 4000m. With a 20 knots facing wind it is very uncomfortable and t 11pm when the wind reaches 25 knots we decided to change course to seak shelter on the western coast of Wallis. We spend the day there, as as soon as we leave the leeward side of the island, the wind is too strong to allow us to work.
We do another station on this side of the island with a deep trawl at 500 m depth and a trawl at 200 m, a wide band echosounder (WBAT) cast and a rosette and CTD cast to establish a vertical profile down to 600m of temperature salinity and fluorescence.

The hatchetfish, profile and front view

Sorting the micronekton organisms

The 2 autonomous echosounders : the TAPS in black for the zooplankton and the WBAT in yellow, wide band sounder for larger organisms. They are lowered down in the water column at each sampling station

Opening the WBAT to charge the battery

When we finished the sampling station last night we decided to steam to get closer to Wallis as the weather forecast is getting worst with increasing wind. We target a seamount on the way to Wallis and we reach it at mid-morning. We steam over the seamount to acquire the acoustic signal; the summit is around 440 m depth, and we observe interesting detections between 300 and 400 m depth. We set the micronekton trawl but without any depth probe we don’t know where we are fishing and the net comes back empty, we missed the detection.
This sampling station on the seamount is very peculiar. The probes on the rosette indicate a fluorescence peak, an index of the quantity of phytoplankton, at 100 m depth with the highest value measured since the beginning of the campaign. Another specific characteristic is the fact that the surface water between 0 and 85m depth is very homogeneous with a temperature at 28.2°C. Below 85m the temperature decreases, the water is at 24°C at 150m and at 6.5°C at 600 m depth.

Acoustic signal showing aggregations of organisms between 300 and 400 m depth

This morning 6 o'clock, the weather seems milder, so we leave our anchorage in Futuna bay towards the south of the area, full of hope. Unfortunately, around 9:30 the sea is still very rough and it is not possible to put the instruments in the water, we are very disappointed. Therefore, we have to go back to Futuna and we decide to conduct a sampling station in these quieter waters. After two CTD casts, Céline, our instrumentalist, detects several weakness points in the electric cable. The cable is cut and then the splice is redone. This small break in the operations allowed us to taste good coconuts offered by the family of a Futunien crewmember who had the joy of meeting his family last night. Then the station resumed with two trawls, the WBAT, two zooplankton nets and the TAPS.

Departure from Futuna bay early in the morning under a beautiful light

On the left, Aurore makes a batter crepe with Christophe the chef and on the right Régis the captain and Valerie enjoy their fresh coconut

Celine welding the electric cable

A juvenile of Chaetodontidae (or butterfly fish, A), a juvenile of Balistidae (or triggerfish, B), a Mysteridae (or mysterious fish, C) and a Pyroteuthidae (or calmar, D)

We left the anchorage this morning to join Futuna. We lower down the dinghy in the water but the swell is too big for us to jump onboard safely. We decide to wait for the agreement of the pilot to enter the bay and we are lucky to see very close to the boat a small whale, probably a small rorqual. In much calmer waters, we leave the vessel in the dinghy and are welcome by a representative of the fisheries services who drives the whole scientific team to the Sisia high school.

The director of the school, the biology teacher and an entire class of 15-16 year old students are waiting for us and during about 1h30 we are presenting our work and discuss with them about our project. We are showing a small movie about the work onboard, probes, a poster on the life in the ocean, the work on phytoplankton and acoustics and we have brought some specimens of fish and crustaceans, caught during the previous days, they are examining with a microscope. The students are very enthusiastic and interested. 

A TV crew from Wallis and Futuna 1ere is following us and interviews the students and the scientists; it will be reported on the radio at lunchtime and later in the evening on television. 

The representative of the fisheries services is then taking us to visit the representative of the French state at his office. We are presenting our project and discuss with him for about an hour.

The specimens we are showing interest the teacher and the students

Presenting the acoustic work

At Sisia High School with the students, the director and the biology teacher

The Wallis and Futuna 1ere TV crew interviewing a student

With the representative of the fisheries services and the representative of the French administration

We conducted our first sampling station at night and it started around 2am with 2 micronekton net tows in the first 100 meters from the surface where all the deep organisms gather at night. The content of the nets is not very rich but we caught some interesting specimens and a large squid. We then conduct a WBAT, wide-band acoustic sounder cast and a first rosette cast to establish the temperature/salinity profile and to collect water. However, the wind is picking up and the sea is getting rough. For safety reasons for the crew, and to avoid breaking our equipment we decide to stop working. 

We then steam towards Futuna, facing the wind and the waves with 25 knots wind and 3 meters swell, the boat moves a lot and anything that has not been tightly fixed is moving across the boat. With the power of the waves, the incubation tank used to study phytoplankton production, which is located against the rail, finally breaks.

Later in the afternoon, we are happy to see Alofi and Futuna islands. We will stay at anchor sheltered between the 2 islands.

The micronekton net setting at night

The catch of the night with a good-size squid

The island of Alofi right ahead

The 4 crew members of the Alis. We drop the anchor in front of Alofi

Musical break at night at anchor

We have steamed all night long and went over 2 seamounts (Waterwitch bank and Combe bank) which summit come close to the surface (about 20 m deep). In the morning, we stop on the western side of Combe seamount to start sampling. We conduct all the different experiments in about 8h30 and it is a little bit longer than we expected but we decided to conduct a deep trawl at 550m depth, which took nearly 2hours and allowed us to collect hachet fish.

The crew members have brought back the zooplankton net onboard

The science team recover the zooplankton collectors

Zooplankton collected on a sieve

A nice tray of deep sea shrimps

A hachetfish. The captain comes and visits us in the lab to see our fantastic catch

Thanks to the 3-stars chef we keep a good morale.

Today we were able to make our first complete station. It boosted the morale of the crew. The weather was not too good, so we decided to make a station close to the coast to stay sheltered. The station started with two CTDs to fetch water at depth. We were then able to make two net tows to look for our first micronekton specimens. We ended up putting the WBAT in the water, the acoustic sounder that goes down to probe the layers.

At the time of writing, we are heading north of the area with the objective of passing over a seamount and sampling another one tomorrow. Our first weekend on board looks busy.

A group of noddy flying and feeding at the surface near the boat.

Launching of the net by the crew members. Tray with specimens captured and sorted in the laboratory for small pictures.

Hatchet fish (top left) with a view from below on their light organs (bottom right). A deadly jellyfish of the Cubozoa family (top right) and some specimens from other groups: crustaceans and mollusks.

The pilot arrives onboard around 6:15am and we leave the lagoon through the narrow pass. We head towards our first sampling station that we chose leeward point with the hope of being protected from the swell. We started working at 8:30 with 2 casts of the rosette to establish a 600m vertical profile of temperature and various parameters and to collect water. Two acoustic casts with the TAPS and WBAT and one zooplankton net later the wind has picked up and with 25 knots the captain decides to stop the work. Unfortunately we will not be able to conduct the micronekton net trawls. We cannot go back into the lagoon so we come closer to the island to seek protection and we will wait for the wind to go down before heading towards the next sampling station.

Leaving Wallis’ lagoon through the narrow pass

First sampling station, everybody has its duties

On the rear deck : the rosette attached after sampling et we are getting ready to lower down the TAPS

During sampling station 1 under heavy tropical rain

We hoped we could leave the lagoon tonight but our departure has been delayed once more as the wind is blowing at 30 knots with 3m waves outside the lagoon. The very last preparation is to put new labels on the vials that will contain the samples. We also work on the sampling plan with less sampling station as we have missed 3 days already, and unfortunately we will not have time to visit the north of the economic zone.

Labelling the zooplankton vials in the officers’ mess

Labelling the bottles to collect seawater, in the lab

The new sampling plan

We are still anchored behind Nukuatea islet close to the pass. The anchorage is quiet but the wind is still strong and we cannot leave the lagoon; the ocean at the horizon is rough. We use this extra day in a quiet environment to work on the acoustic instruments that allow to estimate the small living organisms in the ocean, such as fish.
The WBAT is a wide band echosounder and we put it at the back of the vessel to calibrate it. It is a new instrument and we take a few underwater pictures. We also need to install the surface echosounder. A pole has been added on the side of the boat and we will put the sounder at its extremity. The pole is maintained outside the water when steaming and lowered down in the water when we want to measure the acoustic signal at the surface. The echosounder installed under the boat looks towards the bottom and cannot see the upper 7-8 meters, but with the new sounders mounted at the extremity of the pole we can now observe the biomass of small fish from the surface which are consumed by seabirds, among others. We also test the boat’s echosounder and one member of the team dives under the hull, which allows us to observe the acoustic signal of a human being. Those are the last things we are preparing; we really hope to leave the lagoon tomorrow afternoon as the weather is supposed to improve with winds going down to 17 knots.

At the forefront the lagoon, and behind the islet the ocean with a big swell

The WBAT, a wide band echosounder, suspended in the water and on the deck for cleaning

Installing the surface sounder on the pole; lowering down the pole underwater and underwater view of the pole in position to acquire the acoustic signal from the surface.

In the black circle the acoustic signal of a human being diving under the boat, seen with 2 frequencies (38 and 120 kHz)

The crew members are busy preparing all the equipment

After a long night full of the ship's squeaks and noises against the dock, the decision is made: we leave the wharf. The captain is worry that repeated shocks could damage the hull of the boat. The departure from the wharf is dangerous: the swell pushes the boat against the wharf and it is necessary to avoid that the boat’s rear taps during the rotation. Fortunately the captain and the crew are experienced and the departure is done without any damage. We have finally departed and we are at sea, even if it is not yet offshore and we stay in the lagoon.

So we leave towards the other side of the island, sheltered from the swell and the waves by a small islet. This short transit allows us to admire the 100 shades of blue of Wallis lagoon. We anchor and we are a little bit protected from the swell, even if the wind continues to blow. We start by tweaking the settings of the different acoustic devices and adjust the zooplankton net. Then we enjoy the lagoon, a swim at the back of the boat and we use the small zodiac to go on the beach on the nearest islet. A nice walk on the beach allows us to admire the landscapes of a lost corner of paradise.

Leaving the dock, the waves pass on the front deck of the boat and it is not easy to detach the boat. However, a shock against the wharf exploded a protective buoy.

Before leaving, we must attach everything to make sure it does not move or break. On the right, setting the zooplankton net. 

Small trip to land to stretch our legs and enjoy these beautiful landscapes.

The weather is worse than yesterday. The lagoon is stormy and waves are going over the wharf with wind between 30 and 35 knots and 42 knots gusts. We do not even think to leave, we cannot go through the pass to leave the lagoon and it would not be possible to work outside. We stay along the quay but the vessel is not sheltered and the wind and the swell are sideways. The boat moves a lot, it’s very noisy and it is difficult to sleep.

However, we continue to prepare the lab and the instruments inside the boat as much as possible to avoid the rain. But, for some of the equipments we do not have the choice and we have to go outside. Between 2 showers there are also large waves coming overboard and we finish completely wet. The day was though but we are still along the quay.

In the mess, preparation and cleaning of the WBAT, an acoustique sounder which will be dropped down in the water at each station

The RV Alis along the wharf in the bad weather

Preparing the hydrobios, the zooplankton net

The entire scientific team is now onboard the vessel in Mata’Utu the capital of Wallis. With a terrible weather with strong wind and rain, the boat moves as if it was in the ocean while we are still along the wharf.

On Saturday morning, we are meeting with the director of the service of environment and a staff member of the service of agriculture and fisheries of Wallis and Futuna. They have helped us organising the cruise and they are now accompanying us to visit the king of Wallis who will receive us in his palace. We hence have the opportunity to present our project to the king who thanks us for coming to Wallis. He is interested in our project on the tuna environment that reminds him his participation in the 1990s to the MHLC (Multilateral High-Level Conference) process for the development of the tuna commission in the western and central Pacific.

We then headed to the Territorial Assembly where 4 representatives, the vice-president of the assembly, the president of the finances commission, the president of the education commission and the president of the agriculture and fisheries commission welcomed us. We present our project and discuss with the representatives on the interest of this study for Wallis and Futuna, particularly in regards to the willingness to develop the tuna fishery in the EEZ.

Two television journalists of the Wallis and Futuna 1ère TV followed us this morning to report on our project on Sunday night. We also welcomed onboard 2 professors of the collège and lycée; they will use the information collected for teaching their classes.

In the afternoon, we started to organise the lab and to install all the instruments; this year we have a few extra acoustic gears that need to be set up. Towards the end of the day there is still a lot to do to be ready to go, however the weather forecast is very bad and we know we won’t be leaving the following day as previously planned, so we still have some time to get prepared.

The scientific team with the director of the service of environment and one of his colleagues, and a staff member of the service of agriculture and fisheries from Wallis and Futuna, in front of the palace of the king of Wallis.

Installing equipment in the small wet lab onboard the RV Alis

Despite a 20 knots wind that is increasing and some rain, the vessel continues to progress towards Wallis at 8 knots. It is now located 68 nautical miles in the north of VANUA LEVU (Fiji). During the transit the crew keeps active and prepares the equipment for the voyage. This morning the cable of the oceano winch, which is several hundred meters long, has been unwound and rewound carefully to avoid any problem when using it with instruments. This metallic cable contains an electronic cable which is connected to the instrument at the extremity of the cable and which allow to send instructions to the instrument from the dry lab such as closing the bottles of the rosette to collect sample water at chosen depths.

Connection of the electronic cable to the rosette to send messages to the instruments

The six scientist are still all over the world with four staff in New Caledonia, one in France and one in French Polynesia, and getting prepared for the cruise but in the meantime the vessel is progressing. The captain informed us today that around 5pm they were located north-west of Viti Levu island in Fiji waters. They expect to arrive in Wallis on the 28^th of June.

It is almost dark, around 5pm, when the RV Alis leaves Noumea harbour. The crew is composed of 12 members: the captain, the chief officer and the second officer are at the deck to supervise the navigation, the chief engineer, the second and the third engineers take care of the engine, the chief cook and the steward make sure to maintain a high morale among the crew members, and four seamen including a bosun who will execute all the necessary manoeuvres onboard. It will take them several days to convey the vessel to Mata Utu the capital of Wallis.

All the equipment is onboard and the vessel is about the leave Noumea port

The Wallalis voyage sill only start on 1st of July, however we had to load all the equipment onboard today in Noumea, the home port of the vessel. The vessel will leave Noumea tomorrow and it will take 5-6 days probably to reach Wallis depending on weather condition.

We are loading a lot of equipment and particularly the large micronekton net that will allow us to collect the small fish and squids that are eaten by tuna. We will also use a number of acoustic sounders that require electronic installation work. The small lab is full of boxes of equipment that we need to securely fasten so nothing moves during the transit voyage to Wallis that might be rocky considering that the vessel will navigate sideways to the swell.