The PHOENIX2018 survey aims at automating and optimising the ecosystemic data collection process. The PHOENIX2018 survey aims at testing an « echosonde » comprised of a classical CTD probe fitted with an innovative Simrad EK80 broadband echosounder.

During PHOENIX, we will combine the sampling tools routinely used during the PELGAS survey with the echosonde to characterise prominent sound scattering layers (SSLs). The PELGAS survey led by the EMH lab aims at characterising the Bay of Biscay pelagic ecosystem by combining acoustic and optical tools (multifrequency and multibeam echosounders, optical plankton identifier). The survey provides an echography of the Biscay trophic network from plankton to fish. The SSLs will be first detected using the multifrequency and multibeam hull-mounted echosounders. The broadband echosounder fitted on the echosonde will be lowered within the SSLs, to allow for the characterisation of the coarse taxonomic composition, and abundance at size of mesozooplankton organisms, at a high spatial resolution, along vertical profiles. Various mesozooplankton and micronekton nets will be deployed after each echosonde cast to validate the acoustic characterisation of the mesozooplankton vertical distribution provided by the broadband system. The PHOENIX survey will test the integration of the echosonde on the Thalassa platform, and provide perspectives in terms of new ecosystemic indices production. If the results of the trials are good, the echosonde could be used on any platform operating a CTD to characterise the intermediate pelagic levels in a semi-automatic way.