The importance of the Southern Ocean cephalopod fauna

Extract

The Southern Ocean is probably the last frontier in the field of marine biology. This huge oceanic region is the scene of a very efficient production system yielding high levels of biomass. Within the Southern Ocean food chain the important and conspicuous role played by Antarctic krill is well documented but there is another group of key animals, rarely conspicuous and much less well understood that play a most important intermediate role in the food chain. Although field scientists working in the Southern Ocean have observed an abundant and diverse squid fauna in the diet of vertebrate predators, Antarctic squid have seldom been seen alive. This is in contrast to the situation in seas at lower latitudes where schools of neritic and oceanic squid are regularly encountered at the surface. Marine scientists have rarely been successful in catching Antarctic squid, using either towed nets or jigs, but it has been estimated that standing stock biomass of these organisms in the Southern Ocean may be as high as 100 million tonnes based on an estimate of 30 million tonnes consumed by vertebrate predators. This is clearly a significant resource when compared to the annual catch of the world's fisheries (mostly finfish) which, according to current FAO statistics, amounts to some 100 million tonnes.