On the geographic distribution and migration of I- and II-group eel larvae as studied during the 1979 Sargasso Sea Expedition

During the 1979 Sargasso Sea Expedition, 423 larvae ofAnguilla anguilla and 5 larvae ofA. rostrata were caught on three Atlantic transects and two cruises in the Sargasso Sea. Results of the identification of the larvae by myomere counts, and limits of the occurrence of I- and II-group larvae are presented. Four standard fishing depths are compared. A range shallower than 25 m was found to be the optimal fishing depth by night for both larval length groups. The geographic distribution of length group I was observed in central and eastern North Atlantic. Available data indicate a migration of these larvae in a north easterly direction. Length measurements of the II-group larvae taken from catches on the European continental slope during the same expedition support this assumption.