Results of investigation of the diet of antarctic toothfish Dissostichus mawsoni (Nototheniidae) in the Lazarev Sea

Abstract

131 There are few investigations on the diet of the Ant� arctic toothfish Dissostichus mawsoni. The first data on feeding of this species were reported by Andriashev (1967). He found that from the first year of life the Antarctic toothfish is a clearly expressed predator. Most publications on the feeding of Antarctic toothfish deal with the Pacificand Indianocean sec� tors of the Antarctic Regions. Information on food composition of the Antarctic toothfish in open waters and continental seas of two sectors of the Antarctic Regions is available in publications by Calhaem and Christoffel (1969), Yukhov (1971, 1982), Pakhomov and Tseitlin (1992), Fenaughty et al., 2003), Petrov (2006), Petrov and Filippova (2007), and Petrov and Istomin (2008). The obtained results revealed both similarity and some differences in the diet of Antarc� tic toothfish from different regions. The bulk of the food bolus (by the frequency of occurrence and by weight) consists of fish of the families Macrouridae, Channichthyidae, and Nototheniidae, as well of cephalopods—squids (Psychrotheutidae, Onycho� teuthidae, Cranchiidae) and octopuses (Cirrata and Incirrata). The data on the diet of Antarctic toothfish in the Atlantic sector of Antarctic Regions are reported by Yukhov (1982) and Croshler (1992). According to Yukhov (1982) the investigated Antarctic toothfish taken out of stomachs of sperm whales fed in the open pelagial on whole squids and on their remains. Three species of squids were found in stomachs of toothfish: Morotheuthis knipovitchi, Kondakovia longimana, and Psychroteuthis glacialis. In the area of Elephant island (the South Shetlands) in 39% of the investigated fish 11-119 cm long (n = 38), the stomachs contained no food and in 61% of them mysids and amphipods pre� vailed; Champsocephalus gunnari and Gobionothen gib� berifrons fish were present (Crohsler, 1992).