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F. Antarctic Cephalopods 



Cephalopods include squid, cuttlefish, and octopuses, 

 and are one of the least known groups in the Antarctic 

 marine ecosystem. This lack of knowledge is directly re- 

 lated to the sampling problems (Roper, 1978) resulting from 

 their abaility to avoid nets. They have a highly developed 

 nervous system and motor responses which facilitate strong 

 swimming (El-Sayed, 1977) . Whale and seal stomachs 

 examined by Clarke (1977) in the Southern Ocean showed 

 less species diversity of squid in contrast to what con- 

 ventional sampling gear was capturing. Since these 

 predators usually took Onychoteuthids while the samplers 

 took Pathyteuthids and Brachioteuthids, Clarke concluded 

 that present techniques could give highly biased estimates 

 of which cephalopod families are most abundant. 



1. Distribution 



This group's distribution is generally circumpolar, 

 though certain species appear to occur in restricted 

 localities (Table 21) . Everson (1977) has stated that the 

 Convergence, essentially a surface phenomenon, is unlikely 

 to greatly influence distribution because of the group's 

 diurnal migrations. Filippova (1972) observed that 55% of 

 the known Antarctic squid species are endemic, but few genera 

 are restricted below the Convergence. 



Cephalopods include benthopelagic, bathypelagic , and 

 epipelagic types (Young, 1977). Within the benthic 

 cephalopods, the genus Octopus is rare in the Antarctic 

 where it is replaced ecologically by the genus Pareledone 



(Hureau, 1976) . Octopods appear more frequently near sub- 

 antarctic islands (Roper, 1978) ; Antarctic waters support 

 primarily pelagic squids. In western Antarctica, stocks 

 of Martiola hyadesi are found while Notodarus sloani is 

 abundant in the region between Australia and New Zealand 



(Hureau, 1976) . Also abundant are Bathyteuthis abyssicola 

 and Goliteuthis glacialis , both of which are widespread 

 below about 50° S. Brachioteuthis sp . is extremely common 

 in the Scotia Sea (Filippova, 1972) . The minor squid 

 research that has been done has dealt largely with the 

 Magellanic stocks of Martiola hyaderi and the Australian- 

 New Zealand stock of Nototodarus sloani , two commercially 

 exploited species (Hureau, 1976). How and where population 

 densities of squid are specifically distributed throughout 

 the Southern Ocean is not known. 



2. Movements 



Voss (1973) indicated that squids are short-lived 

 sexually mature in one year and probably spawn only once. 



