Southern rock lobster

Taxobox


name = Southern rock lobster
regnum = Animalia
phylum = Arthropoda
subphylum = Crustacea
classis = Malacostraca
ordo = Decapoda
subordo = Pleocyemata
infraordo = Achelata
familia = Palinuridae
genus = "Jasus"
species = "J. edwardsii"
binomial = "Jasus edwardsii"
binomial_authority = (Hutton, 1875)

The Southern rock lobster or Red rock lobster, "Jasus edwardsii", usually called simply "crayfish", is a species of spiny lobster found throughout coastal waters of southern Australia and New Zealand including the Chatham Islands. The commercial rock lobster fishery is New Zealand's third biggest seafood export earner. Spiny rock lobsters are both carnivorous and filter feeders. They live in and around reefs at depths ranging from 5 to 275 metres deep at the continental shelf. They can be dark red and orange above with paler yellowish abdomens or grey-green brown with the paler underside. The more tropical animals tend to have the brighter colours.

Rock lobsters crawl on the bottom or swim backwards by flexing their tail sharply from extended to beneath the body. Their antenna are sensitive to water vibrations and, where active fisheries exist, they are quite timid and quick to withdraw further into their den. Otherwise they are relatively active ocean-bottom explorers and feed on almost anything that they come across without fear of most predators. Females carry their eggs externally under their tails and normal practice is not to harvest females while they are carrying eggs.

The rock lobster has among the longest larval development known for any marine creature. The phyllosoma (Greek for leaf-like) larvae spend close to two years in oceanic waters before metamorphosing to the postlarval stage, known as the puerulus, which then swims towards the coast to settle.

Food crop

Rock lobsters are caught in "pots" which can be any sort of open-weave or slatted box-like structure with an entry at the top that is V-shaped so that the lower end is well off the floor of the box and relatively narrow. Any form of fish or meat bait is tied into the floor area to attract the rock lobsters. A light buoy on a line from the pot marks the location, and the name of the fisher too. Rock lobsters are quite robust out of water and, if kept cool and damp, will live for many hours — possibly days.

In New Zealand, rock lobsters are an important "kai moana" (seafood) and are caught by non-commercial divers using their hands or a short gaff to haul the rock lobsters out of caves, crevices or tunnels. Rock lobsters are normally found facing outwards and the gaff is positioned under the body shell so that the hook can be located at the join of that shell and in front of the softer tail-joint membranes. The animal is often plunged into boiling water for a few minutes to cook. Some people prefer to have the animal part-frozen before cooking.

Many people in financially well-off countries eat only the tail meat. New Zealanders and many Polynesians, however, tend to eat every part of the animal except for the exoskeleton and the gills.

Rock lobsters, in well-fished areas, may weigh up to 3 kg and are usually found in deeper cool water. In less-fished areas in the southern hemisphere it is not uncommon to catch individuals weighing 10 kg.

See also

*Jasus
*Western rock lobster
*Spiny lobster

References

*cite journal |quotes=no |url=http://www.niwascience.co.nz/pubs/wa/11-2/lobster |author=John Booth, Steve Chiswell, Russ Bradford & Barry Bruce |title=The ups and downs of rock lobster larvae |journal=Water & Atmosphere |volume=11 |issue=2 |pages=17 |year=2003 |format=Dead link|date=May 2008