Toothfish are quite unique. When filleted it is a solid piece of flesh, which is sweet in flavour and highly prized.
One valuable characteristic is that the flesh contains a high level of Omega-3 fatty acids that are released when cooked. Omega-3 fatty acids have become recognised for their health benefits.
Scientific name: Dissostichus eleginoides
Other names: Chilean sea bass
Description: Patagonian toothfish are large, slender fish with a broad head. The body is brownish-grey and covered in large smooth scales. The pectoral fins are large and fan-like. Patagonian toothfish have two dorsal fins, with the first being spiny.
Size (length and weight): Up to about 2 metres in length and 200 kg. Females grow larger than males.
Life span: Up to 50 years.
Habitat: Patagonian toothfish are a deepwater species that inhabits waters on seamounts and continental shelves. They are found at depths of 50‑3000 metres, with adults commonly being found at depths of 750-1000 metres. Juveniles remain pelagic for about year before gradually migrate into deeper waters as they mature. Adults are generally solitary, and relatively sedentary.
Prey: Cephalopods, crustaceans and benthopelagic fish.
Predators: Sperm whales, colossal squid and elephant seals.
Reproduction: Female Patagonian toothfish reach reproductive maturity at about 9 years of age, with most males maturing slightly earlier. Spawning occurs during winter at depths of about 1000 metres on the continental slope. Patagonian toothfish have low fecundity and slow development. Females produce 48 000‑500 000 eggs per spawning season. The eggs are large and are thought to hatch in October-December.
Other notes: Toothfish are named for the sharp teeth on their upper jaw. The name ‘Chilean seabass’ was invented by a fish wholesaler in 1977 looking for a name that would be attractive to the American market.
Scientific name: Dissostichus mawsoni
Other names: Chilean seabass, Antarctic blenny, Antarctic cod, Mawson’s toothfish
Description: Antarctic toothfish are large, slender fish with a broad head. The body is black to olive brown in colour, sometimes lighter on the belly, with four irregular and incomplete dark cross-bars and some dark spots.
Size (length and weight): Up to 2 metres in length and 135 kg in weight. Commonly found at about 1.27 metres in length and 80 kg in weight.
Life span: Up to about 35 years.
Habitat: Antarctic toothfish are a benthopelagic species endemic to the waters of Antarctica. It has a more southern distribution that Patagonian toothfish. They can be found to depths of 2200 metres, but are typically found on the continental slope at 800-1500 metres. Antarctic toothfish are spatially distributed by age and depth, with juveniles are pelagic live in surface waters before moving to deeper depths as they mature. It is believed that Antarctic toothfish become benthic at an age of about 21 months.
Prey: Euphausiids, squid and fish
Predators: Sperm whales, colossal squid, orcas and Weddell seals.
Reproduction: Female Antarctic toothfish reach reproductive maturity at about 17 years of age, with most males maturing slightly earlier at about 13 years of age. Spawning is thought to occur during winter and spring (June-October) at depths of about 1000-1600 metres. Adults migrate to seamounts to the north of the Ross Sea for spawning, and probably remain in the area for 6-18 months before returning to the continental slope to feed and regain body condition. Antarctic toothfish have low fecundity. Females may not spawn every year, and it is uncertain whether they spawn more than once during the year when they do spawn. The eggs are large and are thought to hatch in November-February.
Other notes: The blood of Antarctic toothfish carries compounds that prevent it freezing. Adults are neutrally buoyant.
Toothfish are named for the sharp teeth on their upper jaw. The name ‘Chilean seabass’ was invented by a fish wholesaler in 1977 looking for a name that would be attractive to the American market.
|Fishery found in||Gear used||Catch of species is targeted or incidental|
|Macquarie Island Toothfish Fishery||Longline, trawl and pots||Targeted|
|Heard Island and McDonald Islands Fishery||Longline, trawl and pots||Targeted|
|Ross Sea CCAMLR fishery: Subarea 88.1||Longline||Targeted|
|Ross Sea CCAMLR fishery: Subarea 88.2||Longline||Targeted|
Management of catch
In CCAMLR Subareas 88.1 and 88.2 the catch of toothfish are managed by competitive allowable catches (‘Olympic quota’). This allows a limited number of nominated vessels from Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) member countries to fish for toothfish in these areas. CCAMLR Subareas 88.1 and 88.2 are divided into Small Scale Research Units (SSRUs), and catch limits are set for each SSRU. The Subarea is closed when the allowable catches for each SSRU within that Subarea has been reached.
In the Heard Island and McDonald Islands Fishery and the Macquarie Island Toothfish Fishery the target species, Patagonian toothfish, is managed by quota. This means that the catch of this fish by commercial fishers is restricted by weight. Each year AFMA determines the amount that can be caught in these fisheries using expert advice and recommendations from fisheries managers, industry members, scientists and researchers, and for the HIMI Fishery including experts within CCAMLR.
Management arrangements for the Heard Island and McDonald Islands Fishery and the Macquarie Island Toothfish Fishery are developed annually by AFMA in consultation with the Australian Antarctic Division, CSIRO, the Sub-Antarctic Fisheries Management Advisory Committee and the Sub-Antarctic Resource Assessment Group.
AFMA also requires scientific observers on Australian boats fishing in the Antarctic. Boats must also provide fishing data, satellite tracking of fishing vessel and fishing gear requirements to minimise impacts on wildlife. CCAMLR and AFMA also impose restrictions on the gear that can be used to fish for toothfish.
Commercial fishermen are required to fill in records of their catches during each fishing trip and when they land their catch in a port. This helps us monitor how much is being caught.
In fisheries within the CCAMLR Convention Area, toothfish are predominantly caught by demersal longline operating at 1000-1800 metres on the continental slope and banks, ridges and hills north of the Ross Sea.
Patagonian toothfish are also targeted in areas of the Australian fishing zone adjacent to Heard Island and McDonald Islands (about 2000 nm south-west of Perth) and Macquarie Island (about 800 nm south-east of Tasmania).
Juvenile toothfish and inshore ecosystems and habitats are afforded protection by closure areas and minimum fishing depths
Fishing gear and environmental impacts
The main fishing method used to target toothfish is demersal longline. Trawl gear is also used to catch a small portion of the allowable catch. There are generally low levels of bycatch caught in toothfish fisheries, but occasionally sharks, seabirds and other species may be caught.
Ecological risk assessments are undertaken for the Heard Island and McDonald Islands Fishery and Macquarie Island Toothfish fishery to find out if the fishing of toothfish is harming other species. The most recent assessment for these fisheries was done in 2009 and the risk to other species was assessed as low. The CCAMLR fisheries are reviewed annually by the CCAMLR Working Group on Stock Assessment and the Scientific Committee.
AFMA monitors the catch and status of Patagonian toothfish through scientific studies and species assessments and we work together with CSIRO, the Australian Antarctic Division, the Department of the Environment, and the Commission for the Conservation of Antarctic Marine Living Resources to ensure that toothfish catches remain sustainable.
Want to know more?
This is just an overview of patagonian toothfish, if you want to know more see the links below:
Sustainability – see the most recent Fishery status report
Management – this fish is managed under the Heard Island and McDonald Islands Fishery
Data – Download raw data on annual catches from AFMA catch disposal records and AFMA daily fishing logbooks
Environmental impacts – Bycatch and discard program