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.

Habitat and trophic ecology of Southern Ocean cephalopods from stable isotope analyses

“…K. longimana presented very low δ 15 N values (and high LRL; Fig. 7), but not low enough to be entirely dependent on euphausiids (Table 5) (Nemoto et al 1985(Nemoto et al , 1988, and thus its diet seems likely to include some prey with low δ 15 N values such as crustaceans and myctophid fish (Table 6) Alluroteuthis antarcticus 10 13.6 ± 1 12.3−15.1 10 13.1 ± 0.2 12.8−13.5 10 13.3 ± 0.4 12.8−14 Ommastrephidae Martialia hyadesi 0 10 8.5 ± 0.8 7.3−9.7 10 9.4 ± 0.5 8.5−10 Onychoteuthidae Kondakovia longimana 10 12.1 ± 0.4 11.3−12.6 10 12.3 ± 0.4 11.9−13 10 12.7 ± 0.8 11.2−13.6 Moroteuthis ingens 0 10 12.8 ± 0.2 12.5−13.2 0 Moroteuthis knipovitchi 9 14 ± 0.6 12.4−14.6 10 12.9 ± 0.5 11.9−13.4 10 13.5 ± 0.4 13−14.1 Octopoteuthidae Taningia danae 0 0 5 16.7 ± 0.5 16.3−17.5 (Table 5), which was also within the expected range for a diet dominated by mesopelagic fish (myctophids and paralepids, Table 6) (Cherel & Duhamel 2003). The cephalopods which had the lowest δ 15 N (apart from M. hyadesi and the onychoteuthids, Table 5) are likely to depend on zooplankton that feed in turn on sinking organic matter, since the measured δ 15 N values were higher than expected from organisms that, in some cases, are characterized by gelatinous bodies and small size (except for Haliphron atlanticus, Fig.…”

The trophic link between squid and the emperor penguin Aptenodytes forsteri at Pointe Géologie, Antarctica

“…Fig. 3a) indicates an ontogenetic shift in diet towards prey of higher trophic level, as observed in many marine predatory species (Cherel and Duhamel 2003;Phillips et al 2003;Schmidt et al 2003). Small and/or juvenile squid have been found to consume mostly crustaceans; they switch to a fish-and cephalopod-based diet as they grow larger (Breiby and Jobling 1985;Lipinski 1987;Ivanovic and Brunetti 1994;Pierce et al 1994;Collins and Pierce 1996;Coelho et al 1997;Quetglas et al 1999).…”

Stable isotopes reveal the trophic position and mesopelagic fish diet of female southern elephant seals breeding on the Kerguelen Islands

“…Bradshaw et al 2003), the squid lipid profile may be very similar to other prey such as myctophids, thus constraining the use of fatty acids to assess the importance of squid in the diet of predators (Jackson et al 2007). Within that context, it is remarkable that lipid analysis classified elephant seals with squid known to be primarily myctophid eaters (Phillips et al 2002, and that seals had a δ 15 N value not statistically different from that of the mesopelagic fish-eating warty squid (Cherel & Duhamel 2003).…”