Spatial and temporal distribution of European hake, Merluccius merluccius (L.), eggs and larvae in relation to hydrographical conditions in the Bay of Biscay

摘要

The distribution patterns for hake eggs and larvae were determined by analysing samples collected on 12 cruises in the Bay of Biscay from February to June both in 1983 and 1995. The majority of the eggs and larvae were found in late winter and early spring. The expected northern displacement of both hake eggs and larvae as the season progresses was observed only in the case of larvae. A particular spatial pattern of larval distribution was found. Small larvae (2-4 mm) were found close to the spawning grounds at the shelf break. Mid-size larvae (4-8 mm) showed a more widespread distribution from the continental shelf and to areas well beyond the shelf break. Finally, the biggest larvae sampled (>8 mm) were recorded only on the continental shelf. This pattern seems to be a consequence of the combined action of different mechanisms. Wind-induced transport in the Ekman layer favoured an onshore transfer in 1983, whereas prevalent wind and geostrophic circulation favoured a northern, onshore transfer in 1995.