Annex I

A Brief Description of the Main Species Exploited in the Southern Ocean

Krill (Euphausia superba)

Distribution
Circum-Antarctic south of the Antarctic Polar Front, with centres of abundance in the Scotia Arc and some regions close to the continent in the Indian Ocean sector. Usually confined to the Antarctic surface water (0–100 m depth) in oceanic areas, krill has also been found close to the sea floor down to 350–400 m depth in shelf areas.

Size and Age
Krill grows to a maximum of 64 mm in length and may live for six to seven years.

Biology
Krill attain sexual maturity at two (females) and three (males) years of age. They spawn up to 10 000 eggs between December and March, with considerable interannual variation in timing. Recruitment success appears to be closely linked to the extent of pack-ice in the winter before and after spawning. In summer, krill preys on microscopic plankton, such as flagellates and diatoms, while in winter it feeds largely on ice algae from the undersurface of ice flows. Aggregations of krill can cover many square kilometres and may contain hundreds of thousands of tonnes of krill. Krill is the staple food of many baleen whales, seals, seabirds, fish and squid. Because of its position in the food web between the microscopic phytoplankton and the large vertebrate predators, and its abundance, krill is considered the key species in the Seasonal Pack-ice Zone and parts of the Ice-free and High-latitude Antarctic Zones.

Exploitation
Krill harvesting started in 1972/73 and peaked in 1981/82 (Figure 7). By the mid-1980s annual catches had stabilised at 350 000 to 400 000 tonnes, but they declined substantially at the beginning of the 1990s when countries of the former Soviet Union stopped fishing for krill. Annual krill catches are currently in the order of 90 000 to 100 000 tonnes.

Status
It is unlikely that the present level of fishing will have an adverse effect on the stock(s).

Marbled rockcod (Notothenia rossii)

Distribution
Marbled rockcod is a widely distributed species, found at the northern end of the Antarctic Peninsula, around the Scotia Arc, off Prince Edward, Crozet, Kerguelen, Heard, McDonald and Macquarie Islands, and on Ob and Lena Banks.

Size and Age
The species grows to a length of 85 to 92 cm and a weight of 8 to 10 kg. It can live for 15 to 20 years.

Biology
Three stages of the life cycle of this species have been distinguished: the fingerlings are pelagic for the first 6 to 12 months of their lives, after which they settle on the bottom in near-shore waters, often in kelp beds. They remain in shallow waters for four to six years. On reaching maturity at a length of 43 to 48 cm and an age of five to seven years, they migrate offshore to deeper water, where they recruit to the spawning stock. They spawn from April to June at South Georgia and in June and July near the Kerguelen Islands. The eggs are 4.5 to 5.0 mm in diameter. Fecundity ranges from 19 000 to 130 000 eggs. The larvae hatch in September and October. The marbled rockcod’s food habits are related to the life-history stage: fingerlings feed on small planktonic copepods, hyperiid amphipods and fish larvae; juveniles on amphipods, isopods, fish, euphausiids and algae; and adults mainly on euphausiids, ctenophores, fish and jellyfish.

Exploitation
Marbled rockcod was the target species in the early days of Antarctic fisheries (late 1960s and early 1970s) around South Georgia and the Kerguelen Islands (Figures 2 and 5). Catches exceeded 100 000 tonnes in some seasons, with the highest catch of about 400 000 tonnes at South Georgia in 1970/71 (Figure 2). The species was fished at the South Orkney Islands (Figure 3) and the South Shetland Islands in the late 1970s, with catches reaching about 20 000 tonnes in 1979/80 around Elephant Island. Directed fishing for marbled rockcod was prohibited by CCAMLR in 1985.

Status
Despite being protected for more than 10 years, all exploited stocks still appear to be only fractions of their pre-fishing sizes. Only around the Kerguelen Islands is marbled rockcod beginning to show signs of recovery.

Mackerel icefish (Champsocephalus gunnari)

Distribution
Mackerel icefish is found along the Scotia Arc from Shag Rocks and South Georgia in the north, to west of Adelaide Island (Antarctic Peninsula) in the south, around Bouvet Island and on the Kerguelen–Heard Plateau (Kerguelen, Skif Bank, Heard Island and some nearby seamounts). Mackerel icefish is a shallow-water coastal species found mainly between 100 and 350 m depth, although it is found as deep as 700 m.

Size and Age
This species attains lengths of 60 to 66 cm in the Scotia Arc region and 45 cm on the Kerguelen–Heard Plateau. Maximum ages at South Georgia were estimated as 12 to 15 years, and at Kerguelen 5 to 6 years.

Biology
Mackerel icefish is dependent on the availability of food, preferably euphausiids, in midwater. Krill is its staple food in the Atlantic Ocean sector, with pelagic amphipods and mysids as additional prey at South Georgia. In the Indian Ocean sector, euphausiids other than krill and pelagic amphipods make up the bulk of the diet. The fish becomes sexually mature at about 25 cm (=3 years old) at South Georgia and the Kerguelen Islands, and at about 35 cm (4 to 5 years) in the southern Scotia Arc region. Spawning, with a few exceptions, occurs in coastal waters from February to July in the Atlantic Ocean sector and from April to August/September in the Indian Ocean sector, but with differences in the timing between stocks. Fecundity ranges from 1 200 to 31 000 eggs, depending on the size of the fish and the stock the fish belongs to. Egg diameter is from 3.5 to 4.1 mm in the Atlantic Ocean sector and 2.6 to 3.2 mm in the Indian Ocean sector. The larvae hatch in winter–spring at South Georgia and in spring–summer on the other grounds.

Exploitation
Mackerel icefish was one of the main target species in the trawl fishery for 15 to 20 years after the stocks of marbled rockcod were depleted (Figures 2 to 5). The fishery off the South Orkney and South Shetland Islands ended in the first half of the 1980s, after the two good year classes forming the backbone of the fishery were exhausted (Figures 3 and 4). Harvesting at South Georgia was no longer viable after the end of the 1980s, although a low total allowable catch (TAC) was set to reopen the fishery at a lower level (Figure 2). Currently, the species is exploited at South Georgia and Heard Island, and at the Kerguelen Islands only when a strong year class enters the fishery (Figure 5).

Status
The South Georgia stock recovered from three episodes of heavy exploitation in the mid-1970s and in the early and mid-1980s. However, stock size remained low after a fourth decline following the 1989/90 season. The stocks around the South Orkney and the South Shetland Islands are still only fractions of their sizes at the beginning of the fishery in 1977/78. The stock around the Kerguelen Islands supports a fishery only when a strong year class enters the fishery, and there is evidence that this stock has declined over the last decade. A low TAC has recently been set for the stock – probably never before commercially exploited – living on banks near Heard Island.

Grey rockcod (Lepidonotothen squamifrons)

Distribution
The grey rockcod has a circum-Antarctic distribution around the sub-Antarctic islands and seamounts that lie between them, such as the Ob and Lena Banks in the Indian Ocean sector. The species is found down to 800 m.

Size and Age
The maximum sizes observed were from 50 to 55 cm and the weights from 2 500 to 3 000 g. Fish may live as long as 16 to 20 years.

Biology
Although mostly found at the bottom, the grey rockcod feeds primarily on macrozooplankton, such as euphausiids, pelagic amphipods, jellyfish and salps. The fish becomes sexually mature at 28 to 36 cm (from 5 to 9 years old) at South Georgia and in the Kerguelen Islands. They spawn from October (Kerguelen, Crozet) to February (South Georgia). Fecundity varies from 58 000 to 196 000 eggs, depending on the size of the fish. Egg diameter is from 1.4 to 1.7 mm. The larvae hatch from the end of November.

Exploitation
This species has been exploited commercially, mainly off the Kerguelen Islands and on Ob and Lena Banks. At South Georgia, grey rockcod has been harvested only irregularly, and generally less than 1 000 tonnes per annum has been taken. In the Kerguelen Islands, grey rockcod was the third most important species (after marbled rockcod and mackerel icefish) for almost two decades of fishing (Figure 5). The fishery was closed by the French authorities at the beginning of the 1990s after it became evident that the stock was heavily depleted. The fishery on Ob and Lena Banks, where grey rockcod was the only target species, was closed by CCAMLR at the beginning of the 1990s for the same reason.

Status
Recent surveys suggest that the stock off the Kerguelen Islands is still at a low level; consequently, the fishery remains closed. The status of the two stocks on Ob and Lena Banks is unknown. In recent years, a low TAC was set to provide an incentive to reopen the fishery and to conduct a scientific survey to assess the status of the stock. This TAC was not taken and the fishery was closed again in 1997/98. The status of the stock around South Georgia is also unknown. Directed fishing for this stock is prohibited.

Patagonian toothfish (Dissostichus eleginoides)

Distribution
Patagonian toothfish is widely distributed, from the slope waters off Chile and Argentina south of 30 to 35?S, south of South Africa and south of New Zealand, to the islands and banks in sub-Antarctic waters of the Atlantic and Indian Ocean sectors and Macquarie Island on the Indo–Pacific boundary of the Southern Ocean. Southernmost records of the species are for the South Orkney Islands and the South Sandwich Islands. It is found as deep as 2 500 to 3 000 m.

Size and Age
The maximum size and weight observed are, respectively, 238 cm and about 130 kg. Reliable age estimates for individuals larger than 100 to 120 cm are scarce. However, individuals close to the maximum size are likely to be from 40 to 50 years old or even older.

Biology
Patagonian toothfish feed on a variety of other fish, octopods, squid and crustaceans. They become sexually mature at 70 to 95 cm when they are 6 to 9 years old and spawn over the continental slope from June to September. The species’ fecundity ranges from 48 000 to more than 500 000 eggs, varying with fish length and geographical locality. The eggs, which are from 4.3 to 4.7 mm in diameter, are generally found in the upper 500 m of the water column in waters from 2 200 to 4 400 m deep. They probably hatch in October–November.

Exploitation
Patagonian toothfish are being exploited by longline and bottom trawl both inside and outside the Convention Area where catches were first reported in 1976/77. Longline fishers targeted fish around South Georgia from 1985/86, with annual reported catches of 4 000 to 9 000 tonnes (Figure 2). Fishing was by Soviet longliners in the first few years, but is now mostly by Chilean and Argentinian vessels. Around the Kerguelen Islands, Patagonian toothfish has been targeted since 1984/85, first by the former USSR fleet (later Ukrainian) and later by French trawlers. In recent years, it has also been exploited by Ukrainian longliners. Annual reported catches in this region have been in the order of 1 000 to 9 000 tonnes (Figure 5). Since 1996/97, longlining for Patagonian toothfish has expanded rapidly into the slope waters of previously unfished islands, banks and seamounts in the Indian and Pacific Ocean sectors of the Southern Ocean. In spite of conservation measures implemented by CCAMLR, there is a considerable amount of unregulated and illegal fishing. In the 1996/97 season, estimated catches from unregulated and illegal fishing exceeded those from regulated fishing by a factor of at least five.

Antarctic toothfish (Dissostichus mawsoni)

Distribution
The geographical distribution of Antarctic toothfish is confined to the waters around the Antarctic continent with a northern limit at about 60°S. There are occasional records of this species from as far north as 57°S in the Atlantic and Indian Ocean sectors. Its bathymetric range extends to about 800 m.

Size and Age
The maximum size and weight observed are, respectively, 180 cm and about 75 kg. Individuals of 140 to 165 cm in length have been estimated to be from 22 to 30 years old.

Biology
Antarctic toothfish feed on a variety of other fish, octopods, squid and crustaceans. They are likely to become sexually mature at a similar length to Patagonian toothfish and probably spawn over the continental slope in August–September. The species’ fecundity ranges from 470 000 to more than 1.3 million eggs, depending on the length of the fish.

Exploitation
Since 1996/97 Antarctic toothfish have become the target of a number of new and exploratory fisheries.

Status
The fishery is regulated by precautionary TACs imposed by CCAMLR for new and exploratory fisheries.

Patagonian rockcod (Patagonotothen guntheri)

Distribution
This species is found on the southern Argentine Patagonian shelf, and off the Falkland/Malvinas Islands and Shag Rocks. Single specimens have been found at South Georgia. It is most abundant in waters shallower than 250 m, but has been found at 350 m depth.

Size and age
The species attains a total length of 23 cm. The maximum age recorded is 6 years.

Biology
Patagonian rockcod is apparently benthopelagic, leaving the bottom to feed in the water column. At Shag Rocks this species generally preys on krill and, to a much lesser extent, the hyperiid amphipod Themisto gaudichaudii. It attains sexual maturity when 12 to 16 cm long. The egg size is 1.4 mm in diameter. Fecundity ranges from 6 000 to 23 000 eggs. In the Shag Rocks area, they spawn from September to October.

Exploitation
This species was exploited in the Shag Rocks area from 1978/79 to 1989/90. Because of the small size of the species, catches were mostly reduced to fish meal. The fishery was closed by CCAMLR after it became apparent that the stock was depleted.

Status
The current status of the stock is unknown. CCAMLR has prohibited directed fishing for this species.