Diet of striped dolphins (Stenella coeruleoalba) in southern Spanish waters

Identifiable food remains were analyzed from 46 stomachs of striped dolphins (Stenella coeruleoalba) stranded in southern Spain between 2007 and 2014. Results suggest that the species feeds mainly on mesopelagic and neritic fish, but also on oceanic squids. Fish species of the family Myctophidae were the main prey in terms of numerical importance and reconstructed prey weight (62% N and 29% W), followed by squids of the family Ommastrephidae (20% W) and bogue (Boops boops) (15% W). The most important prey taxa according to the General Importance Index (GII) were C. maderensis, Ommastrephidae gen. spp., Notoscopelus spp., and M. punctatum. Higher number of mesopelagic myctophids were found in dolphins from the Mediterranean (73% vs. 29% N), while more demersal gobiids and European hake (Merluccius merluccius) were found in those from the Atlantic (44% vs. 1% and 8% vs. <1% N), where a more varied diet was also observed. Differences were also seen in the seasonal importance of some prey, as well as between years, sexes, and maturity states. The diet composition suggests that most of feeding occurred in oceanic regions, during twilight and night hours, while the observed dietary variation may reflect differences in topography, and changes in the prey availability.