Home|Search|Identify|Taxonomic tree|Quiz|About this site|Feedback
Developed by ETI BioInformatics
Characteristics, distribution and ecology
Taxonomische classification
Synonyms and common names
Literature references
Images, audio and video
Links to other Web sites

Holthuis, 1963

Diagnosis:
Large spines of carapace broad and flattened, about as wide as long, much larger than the small spines. Sculpturation of abdomen wide, relatively few squamae, with extensive smooth area on anterior part of each somite. First and following abdominal somites with transverse row of squamiform sculpturation behind transverse groove. Frontal horns with upper margin slightly more convex than lower one, more slender than in J. paulensis. Squamiform sculpturation of abdomen coarser than in J. paulensis with squamae fewer and wider.

Type:
Type locality: "Tristan da Cunha", in net off beach. Male holotype in MT; paratypes in MT, RMNH.

Geographical Distribution:
Southern Atlantic Ocean. On the shelf of the islands of the Tristan da Cunha group (viz., Tristan da Cunha, Inaccessible Island, Nightingale Island, and Gough Island), as well as on Vema Sea Mount, 1-680 km ENE of Tristan da Cunha.

Habitat and Biology:
Depth range from 0 to 200 m; the greatest concentration of animals occurs between 20 and 40 m. The species is found on rocky bottoms, sometimes with gravel or shells, in the kelp zone. Ovigerous females were taken in September.

Size:
Maximum total body length, 35.5 cm (males), and 27 cm (females); maximum carapace length, 14.5 cm (males) and 10 cm (females). Average carapace length, 8 to 9 cm. Pueruli are 2 to 3 cm in length.

Interest to Fisheries:
Until about 1950, the fishery of the species was oriented almost exclusively towards local consumption. But in 1949, a Tristan da Cunha Exploration (later: Development) Company was founded and the lobster fishery was developed on a commercial basis; a cold storage and a canning plant were built, and one fishing vessel was operated.
Diesel-powered dinghies were used to bring the catch to the mother vessel for cold storage and subsequent delivery to the factory. The volcanic eruption of 1961 destroyed the shore installations and the company, which had not been very successful anyhow, was liquidated in 1962. In 1963, a new fishing company, the South Atlantic Islands Development Corporation, started operations after the islanders had returned to Tristan da Cunha. A harbour was built and in 1966 a new factory was established. Two fishing vessels with refrigeration facilities on board, worked with a number of dinghies, and resumed fishing operations in 1963. Later the larger fishing vessels were modernized, and the fleet was enlarged in 1971 to 4 vessels with facilities on board for heading the lobsters and freezing the tails. The number of vessels was again reduced in 1978, when there were again two. They were based in Cape Town and operated near the Inaccessible, Nightingale and Gough Islands. They used dinghies and later motorboats to put out and retrieve the nets and traps. From Tristan da Cunha Island, the dinghies and motorboats worked from the shore, the catch being processed in the factory there.
The gear used in the early days was a piece of bait on a long string and weighted with a stone. The bait was lowered into the sea and after a few minutes hoisted to the surface. The lobsters clinging to the bait (often like "a bunch of grapes") were then taken. Later, the dinghies and motorboats used hoop-nets and since 1967, metal traps on long lines. The inclement weather conditions allow only about 70 fishing days a year.
The yield in 1960-1961 was 52.5 tons of tails. Pollock (1981:49) estimated total annual yield at 500-800 tons. FAO statistics give the annual catch for 1987 as 405 tons, and for 1988 as 441 tons.

Tristan rock lobster (Jasus tristani)