Unai Markaida, William F. Gilly, César A. Salinas-Zavala, Rigoberto Rosas-Luis, Ashley Booth,
2008
Aceptado con arbitraje
FOOD AND FEEDING OF JUMBO SQUID DOSIDICUS GIGAS IN THE GULF OF CALIFORNIA DURING 2005-2007
2
CIENCIAS DE LA VIDA
BIOLOGIA ANIMAL Y ZOOLOGIA
ECOLOGIA ANIMAL
Stomach contents were analyzed for 249 large size maturing jumbo squid (Dosidicus gigas) of 35-80 cm mantle length, collected in the central Gulf of California in 2005-2007. Diet was mainly comprised of mesopelagic micronektonic organisms, primarily the myctophids Benthosema panamense, Triphoturus mexicanus, and the squid Pterygioteuthis giardi. This general pattern of feeding on myctophids and small mesopelagic squids agrees with that found in recent studies. Pteropods and crustaceans were less important than previously reported, and the pelagic red crab Pleuroncodes planipes was incidentally important. A sample of stranded squid revealed stomachs full of northern anchovy, Engraulis mordax. Micronektonic myctophids were 33?66 mm in length, weighted 0.2?1.5 g, and represented 5?20% of jumbo squid ML. Cannibalism incidence increased with squid size. We propose that the main prey of jumbo squid derives from the mesopelagic community associated with the upper boundary of the oxygen minimum layer, a well-developed midwater feature in the central Gulf of California. In addition, opportunistic foraging on a variety of organisms supplements their dietary intake. This work demonstrates a need to study the dynamics of the oxygen minimum layer and the composition of the deep scattering layer over the upper slope of Guaymas basin.