Cephalopods of the southern ocean region: potential resdurces and bibliography
Cephalopods (squids and octopuses) are known tobe extremely important organisms in the trophic structure of the Antarctic ecosystems, constituting significant portions of the diets of sperm whales, seals, penguins; pelagic birds and fish. The southern hemisphere population of 500 000 sperm whales, f...
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| Format: | Book Part |
| Language: | English |
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Scientific Committee on Antarctic Research
1981
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| Online Access: | https://oceanrep.geomar.de/id/eprint/33748/ https://oceanrep.geomar.de/id/eprint/33748/6/200.pdf |
| Summary: | Cephalopods (squids and octopuses) are known tobe extremely important organisms in the trophic structure of the Antarctic ecosystems, constituting significant portions of the diets of sperm whales, seals, penguins; pelagic birds and fish. The southern hemisphere population of 500 000 sperm whales, for example, consumes about 50 million tonnes of cephalopods a year, according to Clarke's calculations (Voss 1973. p. 61 ). This value approximates to three-quarter of the world's current annual fisheries production. The highly evolved nervous system of cephalopods allows them to be aggressive, fastswimming predators. This characteristic, unique among invertebrates, makes them comparable in behaviour to many !arge predatory vertebrates. As predators, for example, cephalopods are estimated to consume about 100 million tonnes of Antarctic krill a year (Everson- this volume, paper 4). Knowledge of the biology and species composition of the cephalopod fauna is almost completely lacking, making an assessment of the resource potential of cephalopods in the Antarctic extremely difficult. This Iack of knowledge is due primarily to the strong swimming and net-avoidance capabilities of cephalopods, which have prohibited adequate sampling. Special sampling efforts are required therefore to elucidate their biology and resource potential. Cephalopods inhabit both pelagic and benthic habitats in the Southern Ocean. The squids are primarily pelagic and constitute the major resource potential in terms ofnumbers of species and biomass. The octopuses are primarily benthic dwellers and their biomass and consequent contribution to energy flow are relatively minor in comparison to pelagic cephalopods. This is especially the case in the shelf waters of the Antarctic continent, whereas sub-Antarctic islands appear to support !arger populations of octopuses. |
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