Marine and Coastal Surveys

The BIOMAN survey was originally designed for estimating the biomass of European anchovy (Engraulis encrasicolus) in the Bay of Biscay by the Daily Egg Production Method (DEPM). It is carried out annually in May since 1987 (except in 1993). The anchovy biomass estimates range from a collapsed level in 2005 (5kt) to a historical maximum in 2020 (334kt). These estimates are determined by the Total Egg Production (Ptot) divided by the Daily Fecundity (DF). The estimation of Ptot has improved through more accurate delineation of the spawning area, using CUFES, and with better statistical inference of the egg production per surface unit. DF is mainly driven by the spawning fraction (S) and the relative batch fecundity(F). S estimation procedures have been reviewed after revisiting the degeneration rate of post-ovulatory follicles. Good adult sampling has allowed producing series of population-at-age estimates, allowing tracking cohorts in time. In this period, the survey has broadened its objectives to include concurrent estimates of sardine biomass and to achieve a holistic ecosystem monitoring by regular reporting of environmental variables (including debris and microplastic) and of ecosystem components (zooplankton, environmental DNA, megafauna :mammals, seabird). Thus, the survey contributes both to the integrated assessment of the target species anchovy and sardine and to monitor the environmental status of Bay of Biscay region.