Examination of a small sample of Podocerus chelonophilus found clustered around mucus-exuding epidermal lesions of juvenile loggerhead turtles (Caretta caretta) collected off Madeira revealed the presence of fibrous material in the gut contents. The absence of planktonic remains suggested that these amphipods had been exploiting turtle material directly.

With the exception of the Cyamidae (whale lice), rather few amphipod taxa consistently live in association with marine vertebrates. Sea turtles, however, have been recorded carrying gammaridean and caprellidean epibionts by Caine (1986), who reported eight gammaridean species (including two domicolous fouling species) from nesting loggerhead turtles in Florida.

Stomachs of 385 specimens of Seriola dumerili (Risso, 1810) have been analysed. Their coefficient of repletion is 50·8% in juveniles and 90·3% in adults. Juveniles feed almost exclusively on Teleostei with Engraulis encrasicholus and Sardina pilchardus as the main food; Cephalopoda (Loligo vulgaris and Sepiola sp.) and Crustacea (Squilla mantis) are also eaten. Adults feed on a great diversity of Teleostei headed by S. pilchardus and Merluccius merluccius.

According to Smith-Vaniz (1986)Seriola dumerili is both epibenthic and pelagic, occurring at 18–72 m in small to moderate schools. Juveniles are associated with flotsam in oceanic or offshore neritic waters. Adults often live near reefs or at deep off-shore holes or drop-offs. It is found from the Mediterranean and the Bay of Biscay to South Africa, from Nova Scotia to Brazil, and also in the Arabian Gulf, Australia, Japan and the Hawaiian Islands.