Measuring four times the cautious levels of biomass set for the anchovy’s successful replenishment, the Ministry of Marine Affairs, Ministry of Environment for the Basque Country and AZTI-Tecnalia Basque Country Oceanography presented the results of the Bioman campaign this week.
Surveys conducted throughout May determined a significant increase in anchovy biomass, reaching 138,000 metric tons in the Bay of Biscay against the level of caution set at 33,000 metric tons.
Biologists believe the biomass increase is principally based on a large quantity of existing anchovy aged one year old. Specifically, they describe the anchovy “as a species fluctuating in abundance by nature.”
They report that anchovies’ short life cycle rarely exceeds three years and that growth and survival of juveniles is highly sensitive to environmental factors.
Definitive data analysis was carried out from 24 to 28 June by the Working Group of the International Council for the Exploration of the Sea, which evaluates pelagic stocks including anchovy, sardine and mackerel.
Scientists at ICES, the AZTI Fisheries, Food Technology Institute and French Institute for Research and Sea Exploration made population estimates on Biscay anchovy based on the daily egg production method (DEPM), applying simple lineal and log lineal models to parameters recorded over the whole set of DEPM surveys carried out since 1987.
The 1997 and 1998 studies found that for Biscay anchovy a good relationship exists between biomass and spawning area with temperature an auxiliary variable. These stressed the density dependent occupation of the habitat and set the basis for better stock management and subsequent anchovy recruitment.
