Distribution, growth and survival of anchovy larvae (Engraulis encrasicolus L.) in relation to hydrodynamic and trophic environment in the Bay of Biscay

• Published in: Journal of plankton research 2008-04, Vol.30 (4), p.467-481
• Main Authors: Cotano, Unai, Irigoien, Xabier, Etxebeste, Egoitz, Álvarez, Paula, Zarauz, Lucía, Mader, Julien, Ferrer, Luis
• Format: Article
• Language: English
• Subjects: Animal and plant ecology; Animal, plant and microbial ecology; Bays; Biological and medical sciences; Brackish; Chlorophyll; Chlorophylls; Distribution; Engraulis encrasicolus; Environmental conditions; Environmental factors; Freshwater; Fundamental and applied biological sciences. Psychology; General aspects; Growth rate; Hydrodynamics; Larvae; Marine; Mortality; Plankton; Rivers; Sea water ecosystems; Spawning; Stratification; Survival; Synecology; Winds
• ISSN: 0142-7873; 1464-3774
• DOI: 10.1093/plankt/fbn011

European anchovy larvae were sampled in June 2004 in the south-eastern part of the Bay of Biscay (limits: 4°W, 46°N). Larval distribution was analysed and compared with spawning distribution in previous weeks. Patches of old larvae were found around the French and Cantabrian shelf (CS) edges and even in oceanic waters, far from the main spawning areas, whereas the youngest larvae appeared in the middle French shelf, associated with adult spawning locations. The analysis of environmental conditions showed significant differences from coastal to oceanic stations as well as in areas under the influence of river discharges. A principal component analysis carried out on temperature, stratification, chlorophyll a and plankton concentration distinguished five areas: Gironde, Northern French Shelf, Southern French Shelf, CS and Oceanic area. Growth and mortality rates were estimated for anchovy larvae in these contrasting areas. Advective processes due to dominant north-easterly winds during summer influence larval distribution in the Bay of Biscay after spawning. However higher food concentration on the shelf did not result in significant differences in the growth rate. Mortality rates seem to be negatively related to larval size, although this effect may be partially due to advection. This is the first attempt to study the effect of environmental factors on anchovy larval distribution and mortality in the Bay of Biscay.