Rock lobster
Encyclopedia
Jasus edwardsii, the southern rock lobster, red rock lobster, or spiny rock lobster, is a species
of spiny lobster
found throughout coastal waters of southern Australia
and New Zealand
including the Chatham Islands
. This species is commonly called crayfish or crays in New Zealand and in Māori
. They resemble lobster
s, but lack the large characteristic pincers on the first pair of walking legs.
Spiny rock lobsters are carnivorous, leaving their rock cover to venture out to feed during the night. They live in and around reefs at depths ranging from 5 metre 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. Adult carapace
s can grow up to 230 millimetres (9.1 in) in length and can often exceed 10 kilograms (22 lb) in under-fished areas.
. The eggs develop here for 3 to 5 months. Eggs then metamorphose into naupliosoma larva which leave the female and are free swimming plankton which migrate towards the surface where they moult into a phyllosoma
larva.
The rock lobster has among the longest larval development known for any marine creature. The phyllosoma (Greek
for "leaf-like") larvae spend between 9 months to 2 years in oceanic waters before metamorphosing to the post larval stage, known as the puerulus, which then swims towards the coast to settle.
species in New Zealand is high. Although not commercially farmed yet, this species of lobster has a wild seed stock available and already some commercial companies are harvesting and on growing this seed stock. The National Institute of Water and Atmospheric Research
(NIWA) has reared individuals from egg to adult, showing that it is possible to grow this species in captivity, although it takes between 200–400 days to reach maturity.
This species is also a potential aquaculture species in Australia. There is already a well established export of wild rock lobster from Australia, especially Southern Australia which currently lands just over 3000 tonnes a year. An aquaculture of this species would serve to bulk up the wild catch and add value with high quality grown lobsters.
South Australia currently does have limited aquaculture of Jasus edwardsii, keeping legal sized individuals from the fishery in cages in Kangaroo Island to make them available in the off season, ensuring a year-round supply to market, although no aquaculture from juveniles or eggs is done yet.
to feed the juvenile lobsters, but little is known about a preferred food source. Chopped up mussel flesh has been used previously in Japan. Both these techniques carry some potential disadvantages – brine shrimp can introduce disease, and mussels deteriorate once introduced to the water, giving bacteria an environment to grow on. A study has shown that mussels provide the best food along with a carbohydrate source in the form of agar, allowing faster grow rates in the lobster.
There are three main types of sea cage – floating, wooden fixed, and submerged.
) and research into effective catching of pueruli is currently being done. Research suggests a ‘bottle brush’ collector as the most effective way, a mesh material attached to a PVC core resembling a bottle brush.
The maximum sustainable yield of this seed stock is unknown and research will have to be carried out to determine this before an industry can be founded.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of spiny lobster
Spiny lobster
Spiny lobsters, also known as langouste or rock lobsters, are a family of about 45 species of achelate crustaceans, in the Decapoda Reptantia...
found throughout coastal waters of southern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
and New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
including the Chatham Islands
Chatham Islands
The Chatham Islands are an archipelago and New Zealand territory in the Pacific Ocean consisting of about ten islands within a radius, the largest of which are Chatham Island and Pitt Island. Their name in the indigenous language, Moriori, means Misty Sun...
. This species is commonly called crayfish or crays in New Zealand and in Māori
Maori language
Māori or te reo Māori , commonly te reo , is the language of the indigenous population of New Zealand, the Māori. It has the status of an official language in New Zealand...
. They resemble lobster
Lobster
Clawed lobsters comprise a family of large marine crustaceans. Highly prized as seafood, lobsters are economically important, and are often one of the most profitable commodities in coastal areas they populate.Though several groups of crustaceans are known as lobsters, the clawed lobsters are most...
s, but lack the large characteristic pincers on the first pair of walking legs.
Spiny rock lobsters are carnivorous, leaving their rock cover to venture out to feed during the night. They live in and around reefs at depths ranging from 5 metre deep at the continental shelf
Continental shelf
The continental shelf is the extended perimeter of each continent and associated coastal plain. Much of the shelf was exposed during glacial periods, but is now submerged under relatively shallow seas and gulfs, and was similarly submerged during other interglacial periods. The continental margin,...
. 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. Adult carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
s can grow up to 230 millimetres (9.1 in) in length and can often exceed 10 kilograms (22 lb) in under-fished areas.
Life cycle
Adults are sexual mature at between 7 and 11 years, mating occurs during late summer and autumn. Eggs develop on females, which carry between 100,000 and 500,000 eggs which are fertilised and held below the tail on hairs on the female’s abdomenAbdomen
In vertebrates such as mammals the abdomen constitutes the part of the body between the thorax and pelvis. The region enclosed by the abdomen is termed the abdominal cavity...
. The eggs develop here for 3 to 5 months. Eggs then metamorphose into naupliosoma larva which leave the female and are free swimming plankton which migrate towards the surface where they moult into a phyllosoma
Phyllosoma
The phyllosoma is the larval stage of spiny, slipper and coral lobsters , and represents one of the most significant characteristics that unify them into the taxon Achelata...
larva.
The rock lobster has among the longest larval development known for any marine creature. The phyllosoma (Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
for "leaf-like") larvae spend between 9 months to 2 years in oceanic waters before metamorphosing to the post larval stage, known as the puerulus, which then swims towards the coast to settle.
Aquaculture
The potential for Jasus edwardsii to become an aquacultureAquaculture
Aquaculture, also known as aquafarming, is the farming of aquatic organisms such as fish, crustaceans, molluscs and aquatic plants. Aquaculture involves cultivating freshwater and saltwater populations under controlled conditions, and can be contrasted with commercial fishing, which is the...
species in New Zealand is high. Although not commercially farmed yet, this species of lobster has a wild seed stock available and already some commercial companies are harvesting and on growing this seed stock. The National Institute of Water and Atmospheric Research
National Institute of Water and Atmospheric Research
The National Institute of Water and Atmospheric Research or NIWA , is a Crown Research Institute of New Zealand. Established in 1992, NIWA conducts commercial and non-commercial research across a broad range of disciplines in the environmental sciences...
(NIWA) has reared individuals from egg to adult, showing that it is possible to grow this species in captivity, although it takes between 200–400 days to reach maturity.
This species is also a potential aquaculture species in Australia. There is already a well established export of wild rock lobster from Australia, especially Southern Australia which currently lands just over 3000 tonnes a year. An aquaculture of this species would serve to bulk up the wild catch and add value with high quality grown lobsters.
South Australia currently does have limited aquaculture of Jasus edwardsii, keeping legal sized individuals from the fishery in cages in Kangaroo Island to make them available in the off season, ensuring a year-round supply to market, although no aquaculture from juveniles or eggs is done yet.
Food
NIWA used primarily brine shrimpBrine shrimp
Artemia is a genus of aquatic crustaceans known as brine shrimp. Artemia, the only genus in the family Artemiidae, has changed little externally since the Triassic period...
to feed the juvenile lobsters, but little is known about a preferred food source. Chopped up mussel flesh has been used previously in Japan. Both these techniques carry some potential disadvantages – brine shrimp can introduce disease, and mussels deteriorate once introduced to the water, giving bacteria an environment to grow on. A study has shown that mussels provide the best food along with a carbohydrate source in the form of agar, allowing faster grow rates in the lobster.
Techniques
The most promising technique for aquaculture in New Zealand is sea cages. These have been successfully used internationally to grow similar species. In Vietnam sea cages are used to grow large amounts of Panulirus ornatus (Ornate spiny lobster) in excess of 1,500 t valued at USD$90 million. This species is also commercially cultured in Indonesia and the Philippines.There are three main types of sea cage – floating, wooden fixed, and submerged.
- Floating cages as the name suggests are floating, nets are supported by floating buoys which are connected using a frame. They are often far above the seabed in waters 10 metre deep in calm bays. This type of cage is used in Nga Trang Bay in Vietnam. Wooden fixed cages are near the bottom, or on the bottom of the sea and each net is attached to salt resistant wooden stakes driven into the ground in squares with nets between them. These may be on the seabed with sand covering the bottom of the cage. These cages are used in Van Phong Bay in Vietnam.
- Submerged cages are sealed cubic cages with feeding holes in one end that are attached to the seabed. Similar to crab and crayfish pots used to catch adults. These cages are used in Cam Ranh Bay, Vietnam. Often the materials used to make these cages are sourced locally, in the form of nets from fishing, wood and other framing materials and floats.
- There has been experimental work done in New Zealand with suspended cages which resulted in good grow rates and survivability as long as suitable sites are picked.
Sites
The sites for lobster farms should be in shallow water (not exceeding 20 m) and sheltered from currents and swell as well as potential strong winds. Often behind islands and in sheltered bays are the best sites as the sea cages are easily damaged by swell and high winds. Also the type of sea cage affects the site, floating and submerged cages can be in deeper water, and wooden fixed cages have to be in water only a few metres deep.Seed stock
Due to the time it takes larva to develop (up to two years) the most cost effective method of lobster aquaculture is to harvest wild pueruli. This has been done in Vietnam and has been done previously in New Zealand. This would allow a faster grow time to adults as the caught juvenile will have already had months of growth before being put in cages for aquaculture. There is a good source of pueruli in New Zealand (in places like GisborneGisborne Region
The Gisborne Region is an area of northeastern New Zealand governed by the Gisborne District Council, a unitary authority. Its largest settlement, the city also named Gisborne, is located at the northern end of Poverty Bay on the east coast....
) and research into effective catching of pueruli is currently being done. Research suggests a ‘bottle brush’ collector as the most effective way, a mesh material attached to a PVC core resembling a bottle brush.
The maximum sustainable yield of this seed stock is unknown and research will have to be carried out to determine this before an industry can be founded.