Temperature patterns along the migration routes of European eel larvae towards the south of the Iberian Peninsula

Abstract

This study analysed the variations in sea surface temperature patterns along the two main migration routes of European eel larvae from their spawning grounds (Sargasso Sea) to the southern coasts of the Iberian Peninsula. For this purpose, monthly time series of sea surface temperature associated with theoretical locations along the migratory routes from January 1984 to December 2006 were analysed. The results indicate that regardless of the migration route followed, the temperature pattern was characterized by two periods of maximum temperatures. Likewise, in both routes, surface temperature anomalies indicated the presence of a regime change in the mid- 1990s that significantly correlated with glass eel abundance anomalies in the south of the Iberian Peninsula. Along both routes, strong negative anomalies (mid-1980s, early-1990s and mid-1990s) were associated with positive anomalies of glass eel abundance. In contrast, from the mid-1990s, the negative anomalies of glass eel abundance were associated with a period in which the SST anomalies were clearly positive. These results support the hypothesis that SST is highly important for the recruitment of glass eels in the European coasts.