When and where do fish feed and reproduce? How can we identify their migration routes to better estimate their abundance? The data required to address these issues and thus better study and observe fish requires individual in situ physiological measurements. Obtaining these measurements requires following the fish in their natural environment using modern innovative tools.
Today, electronic tags are used to record data and follow fish movements, i.e. their location and environmental parameters such as temperature. These data are transmitted to a satellite, hence their name “pop-up satellite archival tags”.
These tags have helped better comprehend the environments in which fish travel and live, but do not provide any information on the fish themselves. Another limitation to current tagging technology is that only one-third of the acquired data are transmitted making it impossible to follow the complete trajectory of tagged fish. Moreover, the relatively large size of the today’s tags and their high cost (€4000 per tag) restrict their use and thus their utility for the scientific community.
The POPSTAR project strives to break these barriers and design a new, smaller, more cost-effective tag that will be amenable for marking a larger number of fish.
The project also aims to improve tag technology, particularly through the acquisition of novel environmental and physiological data, and improve data transmission capacity.
The most striking innovation of the POPSTAR project is the in situ recording of information on the physiological state of the fish. “For the first time, it will be possible to assess the physiological state of the fish in their natural environment by, for example, measuring the spatio-temporal variation of its fat content,” explains Xavier André, the POPSTAR project coordinator. The fish environmental sampler will reveal whether it is constituting fat reserves or. or drawing on its reserves for reproduction. At what stages in its life cycle do these variations occur? Is the fish still with its congeners that were tagged at the same time?
All of the data will be transmitted by satellite and then shared with the scientific community. Ultimately, the goal is to create a network of users to compile a novel large-scale database of biological, ecological and environmental data on a large number of marine species. Hence the name POPSTAR: “POP-up Satellite Tag for Advancing Research in marine ecology.”
After sea trials and in situ validation of the prototypes in 2017and 2018 (annual ocean cruises in partnership with local Mediterranean fishers), a flagship action is planned for summer 2019: mark an entire school of bluefin tuna (Thunnus thynnus) in the Mediterranean with the POPSTAR tag.
Once again, the project plans to innovate: cross the line between the study of individual trajectories and the characterisation of movements and the collective behaviour of a whole school of fish. The expected outcomes are numerous, both on the applied level (enhance fisheries expertise) and on the basic science level for marine biodiversity knowledge in general. The POPSTAR project has the potential to elucidate the relationships between the environment and the physiology of marine organisms, a major scientific challenge in the context of climate change, particularly in the Mediterranean Sea.
The POPSTAR MERLIN project will be conducted by IFREMER in close collaboration with the two research units: UMR LIRMM (Laboratoire d'Informatique, de Robotique et de Microélectronique, University of Montpellier - CNRS) and UMR MARine Biodiversity, Exploitation and Conservation (UMR Marbec, IFREMER - IRD — University of Montpellier - CNRS).