Diet of the squid Moroteuthis ingens (Teuthoidea: Onychoteuthidae) in the upper slope waters of the Kerguelen Islands

Abstract

The diet of the onychoteuthid squid Moroteuthis ingens was investigated through stomach content analyses of 72 individuals collected aboard a trawler targeting Patagonian toothfish Dissostichus eleginoides in the upper slope waters of the Kerguelen Archipelago. M. ingens is primarily piscivorous (67% by number and 87% by reconstituted mass), although the diet also includes squids (12 and 12%, respectively) and crustaceans (21 and <1%, respectively). The main fish prey were the paralepidid Arctozenus risso (28% by reconstituted mass), the gempylid Paradiplospinus gracilis (24%) and various myctophids. M. ingens preyed also upon conspecifics (cannibalism, 6%), and the euphausiid Euphausia triacantha was the main crustacean item. Most of the prey are pelagic organisms performing diurnal migration, suggesting that the benthopelagic M. ingens catch them when they are near the bottom during the day. In turn, M. ingens is a prey for several species of top predators, including D. eleginoides and air-breathing vertebrates. M. ingens thus contributes to carbon export from the pelagic environment to the benthos and from the ocean to the atmosphere as carbon dioxide expired by birds and mammals.