Diet of the common cuttlefish Sepia officinalis (Linnaeus, 1758)(Cephalopoda: Sepiidae) in the Southern Moroccan Atlantic waters, Cap Boujdour, Cap Blanc

The diet of the cuttlefish Sepia officinalis was studied for the first time in the Southern Moroccan Atlantic waters during an annual cycle between September 2013 and October 2014. Samples were collected from bottom trawl surveys and commercial artisan catches taken between cap Boujdour to cap Blanc (26°N-21°N latitude). A total of 479 individuals (252 male and 227 female), ranging between 4 and 40 cm DML and of total weight (W) ranging between 18 and 4,750 g are studied. A qualitative and quantitative analysis was realized according to sex, size and sampling season. The stomach contents were analyzed using five indices: frequency of occurrence (F%), percentage by number (Cn%), percentage by weight (Cp%), Index of Relative Importance (IRI %) and Feeding Coefficient (Q). Trophic activity was assessed using the stomach vacuity coefficient (v%). A MANOVA test was used to compare the quantitative composition of the diet according to seasons, size and sexes. According to the results of the index of relative importance (IRI%) of the stomach contents (which takes into account weight, number and frequency of occurrence), fish and crustaceans are the most consumed prey category representing respectively 51.36% and 42.56% and are considered as a principally prey of S. officinalis. Cephalopods occurring in 13.78% of non-empty stomachs, accounting for 7.71 % of preys in number and 18.79% in weight are considered as a secondary prey for S. officinalis. The evolution of the vacuity coefficient shows that this index varies according to the sexual cycle and season. Significant seasonal variations in the diet were observed. It is proposed that seasonal differences in diet composition are caused by spatial and temporal variations in abundance and distribution of some of the major prey species. No significant differences in the diet between males and females were found. Differences in food composition between jveniles and adult individuals appeared to be influenced by the S. officinalis size and the reproduction period. In specimens with dorsal mantle lengths up to 15 cm crustaceans dominated, occurring in 54.63% of examined stomachs and made up (57.27%) of (IRI%). Important prey categories of the adults (>15 cm DML) were fish with (IRI%= 54.49%), followed by crustaceans (IRI%=37.86%) and cephalopods (IRI%=5.73%). The variations of S.officinalis diet in the studied area indicate an opportunistic character of this predator as cited in many studies in other regions of the worl