Today the Patagonian toothfish (Dissostichus eleginoides) is the most valuable fishery in Antarctic or subantarctic waters. Prices can exceed $US10 per kilo for headed, gutted and tailed fish in the main markets in Japan and the United States. Unlike nearly all other Antarctic fish, the toothfish can grow to a large size (just over 2m long and 100kg in weight) and this, together with its high quality white flesh and few bones, make it highly sought after — particularly given the growing scarcity of other premium-quality species from around the world.
This has led in the last few years to a large-scale illegal fishery, which attempts to poach fish from the major areas of distribution of the toothfish around the subantarctic islands and other submarine ridges in the Atlantic and Indian Ocean sectors of the Southern Ocean. Large numbers of vessels fishing illegally were first noticed in 1996 in the western part of the Indian Ocean, but they soon spread eastwards towards Kerguelen and Heard Islands where they were seen by Australian and French licensed vessels in 1997. Although difficult to estimate reliably, it is thought that illegal catches were very high in these first couple of years — possibly two to three times the legal catch of this species from all sources — and probably caused a significant depletion of the fish stock in some localities. As a result of surveillance and arrests by some countries, including Australia, illegal fishing has declined. It still however remains a serious problem, with illegal catches being similar to the level of legal catches in the 1999–2000 season.
Since the start of fishing activity in subantarctic waters in the early 1970s, toothfish had been a minor bycatch species in the trawl fisheries for marbled rock cod and grey rock cod, particularly around South Georgia and the Kerguelen Islands. It was only in 1985 that commercial quantities of toothfish were discovered at Kerguelen. There had, however, been a substantial fishery off the Chilean coast since the mid-1970s, so markets were already established for this species. Since then, the fishery for this species developed rapidly and expanded to other areas, including South Georgia, Marion and Prince Edward Islands, and Crozet Islands. In 1994 an Australian trawl fishery began at Macquarie Island, followed by Heard Island in 1997. Although started as a trawl fishery, most toothfish is now caught by longline, except for the Australian fishery and part of the French fishery at Kerguelen. In the 1999–2000 season, approximately 14,500 tonnes were caught in the subantarctic waters managed by CCAMLR and a further 11,500 tonnes were taken outside CCAMLR waters off Chile, Argentina and the Falkland Islands.
Patagonian toothfish is now known to occur throughout the southern hemisphere in cool temperate and subantarctic waters, from the east and west coasts of South America eastwards through all of the subantarctic islands, submarine plateaus and seamounts to the Campbell Plateau south of New Zealand in waters from 300m to over 2000m depth. It probably also occurs in the Pacific sector, but little exploration has been done there. It is replaced in the high latitudes close to the coast of Antarctica by its close relation, the Antarctic toothfish (Dissostichus mawsoni), for which a fishery is currently being developed.
About Patagonian toothfish
Patagonian toothfish are caught close to the sea bed and most fishing occurs between 400m and 1500m depth. They are large, active, predatory fish that feed mostly in the water column on squid and fish, but they have a very varied diet that can include bottom-living organisms such as crabs and prawns. Studies on their age and growth are not yet conclusive, but it appears that they can live at least 45 years, with males maturing at about 10 years and females at about 12 years. Spawning is thought to take place in winter (June–July) in depths of at least 1500m. Young stages spend some months at least in surface waters before moving to the sea bed where they appear to move deeper as they grow. Tagging experiments suggest, surprisingly for such an apparently active large species, that fish generally do not move more than a few tens of miles over a period of several years. Recently, however, there have been two instances of tagged fish recaptured at different islands several hundred miles from their tagging position, so the extent to which fish interchange between different fishing grounds is not yet resolved.