Habitat and Diet of Early Stages of Sepia Officinalis L. (Cephalopoda) in Morbihan Bay, France

The nursery grounds of Sepia officinalis were identified in the Gulf of Morbihan, on the Atlantic coast of France, and their abiotic and biotic features described. From the measurement of the young cuttlefish captured, their growth and development could be followed through a period of five months. Analysis of the stomach contents of the cuttlefish and identification of the prey consumed gave a measure of their feeding activity and diet. The young animals were concentrated in the two parts (East and West) of Morbihan Bay. These were distinguished by different sediments (sandy-mud in the East and sand with shell-debris in the West) and by water temperature (higher in the East which allow a greater growth of the young cuttlefish). These sites are rich in crustaceans Amphipoda, Brachyura and Macrura which compose the diet of young cuttlefish. Fish (Gobiidae and Syngnathidae) appear in the diet from August. The feeding activity of the cuttlefish (given by the repletion quotient) increased from June to August reaching about 80% in both parts of the Bay. It decreased to nearly 50% in September and October.