The spawning environment of the Bay of Biscay anchovy (Engraulis encrasicolus L.)
L. Motos, A. Uriarte and V. Valencia

The spawning season of the Bay of Biscay anchovy population extends from March to August, although most of the reproductive effort is made during May-June. Spawning is triggered by the warming up of surface waters and coincides with the maximum rate of temperature rising and the onset of stratification. Preferential sea surface temperatures are in the range of 14 - 18°C. This population shows a relatively short peak spawning period that seems to be an adaptation to stable and predictable environmental conditions in the SE Bay of Biscay. At the beginning of the spawning season, usually in April, anchovy concentrate in the SE corner of the Bay of Biscay. Later, in May, anchovy spawning is prevalent in the SE Bay of Biscay. As the spawning season progresses, in June, distinct coastal and oceanic spawning areas appear. Simultaneously, the geographic range of spawning extends north and westwards. The Bay of Biscay anchovy selects stable habitats related to river plumes, shelf edge fronts and oceanic eddies, where increased biological production potentially occurs. i) There are low salinity plumes related to main river estuaries (Gironde, Adour and Bidasoa); ii) structures related to shelf break fronts - French shelf to the North of 45 N and southern Bay of Biscay-; and iii) oceanic eddies of slope waters (SWODDIES), in oceanic sites outside the continental shelf. The population shows a density-dependent selection of the spawning habitat. The spawning areas associated with the Estuaries of Gironde, Adour and Bidasoa, in the SE region of the Bay of Biscay, seem to form a refuge basin favourable to the maintenance of this population of anchovy even in adverse environmental conditions.

Keywords: Anchovy, Engraulis encrasicolus, spawning, environment, Bay of Biscay.
Contents of this volume Sci. Mar. 60(Suppl.2) : 117-140 Back PDF
Please, send comments to
ICM (CSIC) - Passeig Marítim de la Barceloneta, 37-49. E-08003 Barcelona (Spain)