Role of the Nutritional Condition of Breeding Anchovies in the Subsequent Recruitment to their Population in the Bay of Biscay (NE Atlantic)

The recruitment of marine fish populations is a central concern of fisheries scientists. Multiple research pathways have been explored, with emphasis of the causes of mortality affecting principally the early developmental stages of fish life. The small data set presented focuses on a feature often inadequately considered, i.e. the nutritional condition of the breeding parent fishes estimated from the levels of the RNA/DNA ratio determined in fish white muscle. This is applied to the European anchovy population inhabiting the French continental shelf of the North-East Atlantic Ocean. In four of the five years analysed, the annual recruitment shows a tight relationship with the mean values for the RNA/DNA ratio determined in the parent fish during the previous breeding season. One year is clearly distinguished from this model, owing to a strong drop of the recruitment, of which an explanation is tentatively advanced. This drop coincides with the beginning of a strong collapse of the population. A very low level of the anchovy biomass will last ten years. The role of the nutrition of breeding fish in the recruitment success is discussed in connection with the literature that emphasized the importance of conditions providing fish with sufficient fuel during the crucial period of its gametogenesis, particularly in clupeoids and anchovies.