From 03 to 23 April and from 04 to 22 June 2019
NEW CALEDONIA 2019 MISSION – PACIFIC
- ADN environnemental, deep sea, Environmental DNA, megafauna, New-Caledonia, sharks
The MEGAFAUNA project
A large inventory was undertaken throughout the world to census the marine magafauna: fish, marine mammals, sharks, turtles, etc. The mission in New Caledonia is one of the stages of this large-scale operation.
Exploring the unknown
Two missions took place respectively in Avril and June 2019 from New Caledonia on board the Alis, an oceanographic vessel of the French Research Institute for Development (IRD), based in Nouméa.
Their research project: exploring the isolated islands and the seamounts of the Coral Sea to study, identify and assess the marine wildlife found there.
These operations were conducted under the direction of Laurent Vigliola (researcher at IRD, Seamounts programme financed by the French National Agency for Research and the Coral Sea Natural Park) and David Mouillot from the University of Montpellier, Director of Research at the MARBEC (MARine Biodiversity, Exploitation and Conservation) Mixed Research Unit.
Seamounts, an oasis of life?
The seamounts of the Coral Sea rise to an altitude of more than 1 000 above the seabed. Their peaks outcrop at a depth from 50 to 100 m under the surface, and they remain largely unknown. To date, only 4% of these areas have been sampled for scientific purposes. Yet there is every reason to believe that these unique ecosystems support oases of life and biodiversity hotspots.
Risk of species overexploitation
Those deep areas and the animals they shelter are highly threatened by the growing fishing pressure, which exposes some species to a risk of overexploitation, or even extinction. The protection of marine animals such as sharks and other large vertebrates is now at the heart of environmental concerns. The exploration of these ocean depths is essential to better know them and hence better protect them.
Scientific hypotheses and innovative techniques
To detect the species present in these deep areas, two main techniques are deployed: water sampling to study environmental DNA and baited cameras.
Location
– Environmental DNA
The principle is based on the study of DNA traces (fingerprints) which persist in the water after the passage of a species. The aim is to collect sea water in a given place at targeted depths, to filter it, isolate the DNA and compare it with a catalogue of existing data (reference database) to know which species was present, where and at what time.
– Baited cameras
Baited cameras are part of the techniques for studying marine wildlife outside of any human presence, and therefore without disturbing the behaviour of animals. Installed in the water column or on the seabed, they record images of the wildlife attracted by a bait placed in front of the lens. The researchers discover in this way the diversity of species inhabiting the ocean depths, estimate their quantity (the ‘biomass’) and study their behaviour. Operated according to a precise protocol, the baited cameras make it possible to monitor the evolution of an area over time and to compare geographically remote areas.
Linking two techniques
Using these two complementary techniques, the scientists hope to provide some answers to several hypotheses; do the seamounts constitute biodiversity oases? Which vertebrates really find refuge in these deep areas in the face of human pressures? Are the large vertebrates simply out of reach of humans in these deep areas and not at all declining?
The continuous thread of Monaco Explorations
Supported by Monaco Explorations, these techniques with no impact for animals were tested and improved several times, in particular during the transatlantic crossing and the Sargasso mission, but also in Colombia, in Malpelo or subsequently during Laurent Ballesta’s Mediterranean Planet mission. Mission after mission, the labyrinthian thread of biodiversity is untangled and gradually brings many discoveries.
Many species still to be referenced
Today only 16% of species are genetically referenced. A huge collection and sequencing work therefore remains to be performed to complete the reference database. During the missions on the Alis, targeted samplings were also organised to collect samples of fin fragments on fish in order to extract the DNA and hence reference them through the sequencing of their DNA.
The results already!
Since the beginning of the missions supported by Monaco Explorations, 1 000 new species have been added to the environmental DNA reference database. Out of the 6 000 known species of tropical vertebrate fish, only 2 000 had been sequenced until then. Since 2017, 1 000 new species have been added through the work conducted as part of the MEGAFAUNA project.
International database
This reference database is shared internationally by all the scientific community and facilitates identification of the marine species using a given area.
Testimony of Laetitia Mathon, doctoral student and member of the mission
During this mission, we worked on completing the tropical fish reference database. Indeed, in order to recognise the species (via their DNA) in the environmental DNA samples, their sequences must first be known. For this, we extracted the DNA contained in samples stored in freezers of the IRD, and we also collected fish tissues at the Nouméa market. This DNA was then sequenced, and we obtained 122 new sequences. During this mission, we also implemented the video image capture by overflight of the lagoon, to identify the megafauna.
The Coral Sea Natural Park
In 2012, the agreement signed for the creation of the Coral Sea Natural Park in New Caledonia (1,300,000 km2) made it one of the largest marine parks in the world. It represents 12.7 % of the French maritime area and encompasses 55% of the coral reefs of New Caledonia. The Government of New Caledonia is currently working on the precise spatialisation of the park. This consists in deciding which particularly remarkable areas will be sanctuarised, and which other areas can be subject to rational human exploitation.
A significant help in decision-making
The zoning process requires the compilation of existing information and support to initiatives aiming to collect new information useful for the establishment of the park. The data collected by the team of Laurent Vigliola and David Mouillot directly contribute to the information provided to the New Caledonia Government. They provide very valuable new knowledge on the biology and habitat of vertebrates for the Coral Sea Natural Park’s establishment process.
The Alis
The Alis is a vessel of the French oceanographic fleet which operates in the South-West Pacific Ocean from French Polynesia to Papua New Guinea. It is based in New Caledonia. It carries out physical oceanography (bathysounder, hull-mounted doppler current profiler ), biology (instrumented trawls, sounder for observing the water column EK60), and bathymetry (multibeam sounder EM1002) missions. It is also used as a support ship for diving missions (biodiversity study).
Mission members
David Mouillot
David Mouillot, from the University of Montpellier, Director of Research at the MARBEC (MARine Biodiversity, Exploitation and Conservation) Mixed Research Unit and his team have been interested for a number of years in the distribution of the megafauna in the deep areas where seamounts are found. In collaboration with Monaco Explorations, his team collected data in several areas of the world using the environmental DNA and baited camera techniques. David Mouillot was appointed this year ‘senior member’ of the Institut Universitaire de France.
Find these works here.
— Dr. Laurent Vigliola
Laurent Vigliola is a researcher at the Nouméa IRD where he studies coral reef fish on local, regional and global scales. Leader of these last two expeditions on the Alis, his research focuses on coral ecosystems and the complexity of connections between species. He uses various tools such as dive counts, analysis of fish otoliths (age, growth, microchemistry), light traps, acoustic telemetry, environmental genetics, population genetics and modelling. Learn more here.
— Laetitia Mathon
Laetitia is a young doctoral student from CNRS, in partnership with the Entropie Mixed Research Unit (UMR) in Nouméa, and the SPYGEN company. With a passion for marine animals, their ecology and the mysteries surrounding them, she has started a thesis on the study of fish distribution in little known environments such as the seamounts or the deep sea.
— Nadia Faure
Nadia is currently studying biology at the University of Swansea in Wales as part of an exchange with her university of origin Grenoble Alpes, for her 3rd year of undergraduate studies (Licence). Although she was born in the mountains, she has been passionate about underwater life since her childhood, which led her to do a voluntary work placement and to take part in this marine ecology research mission.
Sampling campaigns
After the two operations of April and July 2019, two campaigns are planned in 2020. In total, twelve seamounts and four coastal reefs will be studied
The Principality of Monaco committed
To protect marine biodiversity and halt the general decline of large marine predators such as sharks, an increasing number of countries have recently decided to act and create giant Marine Protected Areas (MPAs).
H.S.H. Prince Albert II, who is particularly involved and convinced of the importance of Marine Protected Areas, mobilises the Principality and the international community. This commitment efficiently contributes to creating favourable conditions for a sustainable protection and building capacity to reach this objective.
