-86- 



and within species and continental shelf areas are likely 

 to be important (Everson, 1977) . Fecundity increases and 

 egg size decreases along a gradient from south to north 

 among related genera such as Trematomus and Notothenia 

 (Andriashev, 1965; Permitin and Schlyanova, 1971), as 

 well as in the families Chaenichthiyidae, Mucsenolepidae , and 

 Bathydraconidae (Permitin, 1973) . 



The development of ova may take up to two years in 

 ( Notothenia neglecta ) (Everson, 1970); gestation periods 

 several months (3 to 4 in Chaenocephalus aceratus, Everson, 

 1968) ; and larvae may not undergo metamorphosis into adults 

 for extended periods (Everson, 1968, 1970). Many species' 

 young often show extensive pelagic adaptations, a feature 

 believed to facilitate at-sea phytoplankton exploitation and 

 one which is lost during adult benthic stages (Marshall, 

 1964; Andriashev, 1965) . Growth is slow, mortality is 

 high, and sexual maturity is not reached for several years 

 (Everson, 1977; 1970; Dearborn, 1965; Wohlschlag, 1962). 



Estimates of Southern Ocean fish production have been 

 made based on estimates of annual consumption by predators 

 (Table 19). This table includes many Antarctic fish species, 

 not just those of commercial potential. Therefore, produc- 

 tion figures may be lower although to an unknown extent. 

 Production of sexually mature fish is probably about 5 

 million tons (Everson, 1977) . 



6. Food Habits 



The dietary importance of krill to many resident and 

 seasonal Antarctic fishes was originally felt to be rather 

 insignificant (Marshall, 1964). Recent findings (Table 20), 

 however, suggest that fish consume more krill than previously 

 thought (Nasu, 1968) . While in their summer feeding grounds 

 in the Scotia Sea, a variety of species feed on krill 

 (Permitin, 1969, 1970; Olsen, 1955). 



In the South Georgia area, Permitin and Tarverdujeva 

 (1972) observed that krill were principal foods in 6 species, 

 secondary food in 3 species, and tertiary food in 1 species. 

 One-thousand stomachs of adult southern blue whiting were all 

 full of krill (Permitin, 1970) . In the Scotia Sea, krill were 

 found in 31 species of 12 families and inhabiting bottom, 

 bathypelagic, pelagic, and epipelagic habitats (Permitin, 

 19 70). Off Queen Maud Land, Kawamura (1978) observed 

 that many sampled fish subsisted largely on krill. Knox 

 (1970) stated that "recent Russian work indicates that the 

 stocks of fishes are very much higher than formerly estimated. 

 Thus, the amount (of krill) consumed by... (fish and 

 cephalopods) .. .could be at least of the same order as that 

 formerly consumed by the whales." 



