Southern Rock Lobster

Introduction

Also known as Rock Lobster, Red Rock Lobster and Crayfish, Southern Rock Lobsters are distributed from northern New South Wales, south around Tasmania and across South Australia into Western Australia.

Southern Rock lobsters live in a variety of habitats on the continental shelf, in water from 1 metre to approximately 200 metres deep.

There is no evidence of mass migration of the Southern Rock Lobster, however movements of up to 89 kilometres have been reported, as well as shorter distances from inshore to deeper offshore waters. In many location rock lobsters show little movement.

Southern Rock Lobsters are carnivorous and eat molluscs, small crustaceans, echinoderms and other benthic invertebrates.

Major predators of both adult and juvenile southern rock lobsters are octopus, gummy sharks, fish such as southern rock cod, flathead, wrasse, morwong, conger eels and rock ling.

Lobsters include large crustaceans from two groups, one with a pair of large claws and the other without. Clawed lobsters, yabbies and freshwater crayfish, live only in rivers and lakes in Australia but in the northern hemisphere there are marine representatives too. Marine lobsters, some of which are also called crayfish in Australia, do not have claws and are the ones figured here. The carapace is calcareous and tough, reinforced to protect the internal organs of the head and thorax and the gills at the bases of the legs.

The antennae are obvious, the compound eyes are on mobile stalks, there are six pairs of small limbs around the mouth, and five pairs of walking legs. The abdomen is strong and muscular, with a strong segmented exoskeleton on the back. It has the swimmerets underneath and ends in a tail fan.

During mating the male lobster transfers a packet of sperm to the female where it sticks and appears as a “tar spot” between the last legs. The eggs are laid through holes at the bases of the third pairs of legs and are attached to hairs on the swimmerets where the embryos develop until they hatch. As many as 600 000 eggs may be carried by a large adult female. The eggs of Australian marine lobsters hatch as a larva called a phyllosoma. The translucent flat phyllosoma lives in the plankton for up to 22 months. In the Western Australian species of rock lobster the phyllosoma passes through nine instars lasting 9-11 months and is transported by currents well into the Indian Ocean before moulting to a stage looking much like a translucent miniature adult. This stage swims across the continental shelf to settle in shallow inshore reef areas.

The abdomen of the palinurids is large, muscular and edible. In Australia lucrative fisheries exist for the commonest species. Fishing is usually by the use of baited pots set from small boats close to shore. Because they are so commercially important much is known about the biology and fisheries of spiny lobsters. They inhabit shallow nearshore rocky or reef environments, rarely to 1000 metres depth. They are cryptic, hiding in rock crevices during the day and coming out at night to feed. Analyses of stomach contents tell us that they usually feed on small invertebrates and occasionally on algae.

Southern rock lobster are distributed widely across southern Australia from northern New South Wales, around Tasmania, across to Dongara in Western Australia and are also present throughout New Zealand waters.

Lobsters vary in colour from usually reddish-purple in shallow water, to purple and creamy-yellow in deeper offshore waters.

Mating occurs during the months of April to July, with most eggs hatching between September and October. Fertilisation occurs externally, where the fertilised eggs are carried under the tail of the female for 4-6 months. Eggs are extruded from a genital opening at the base of the third pair of walking legs. Female lobsters carrying eggs are known as "in berry" or "buried". A large female can carry up to 400,000 eggs.

During the spawning season, some female lobsters may have eggs beneath the tail. These lobsters are totally protected in South Australian waters and must be returned to the water immediately.

Rock lobsters have several recognisable life stages. After hatching, the planktonic larvae (phyllosomes) disperse widely with the ocean currents and have been located hundreds of kilometres offshore.

This phase of the lobster life cycle lasts between 9 and 20 months, after which the phyllosomes change (metamorphosis) into transparent puerulus, which resemble miniature lobsters in shape.

These puerulus settle in inshore reef areas and soon after settling, moult into bottom dwelling juvenile lobsters.

Southern rock lobster lives in a variety of reef habitats, ranging from shallow rock pools, out to the continental shelf.

Male and female lobsters are distinguished by several physical characteristics.

Possibly the easiest method of distinguishing males from females is the difference in the fifth walking legs (counting from the front to back). In females, the fifth or last pair of walking legs terminate in a small claw. This claw is used to tend to the eggs under her tail during the spawning season. Males do not have this claw, with their fifth walking leg ending as a single point.

Another method of quickly determining the difference between male and female rock lobster is the location of the genital pore. In males, the genital pore is located at the base of the fifth walking leg. In the female rock lobster, the genital pore is found at the base of the third pair of walking legs, where the eggs are released.

A third method for determining the sex of the rock lobster is by looking at the pleopods (swimmers) located under the tail. Female rock lobster have inner and outer pleopods which are used to carry eggs, whilst the male rock lobster has four pairs of single pleopods.

A rock lobster is undersize in the northern zone if its’ carapace length is less than 10.5cm. Failure to clip the middle tail fan may result in prosecution with a maximum penalty of $2000.

Rock lobster must be measured along the middle and on top of the carapace from the front edge of the groove between the antennae, to the rear edge of the carapace. This measurement does not include and hairs attached to the carapace. Any measuring device must fit firmly into the groove between the antennae.

The boundary of the northern and southern rock lobster zone is longitude 139 E, located East of the Murray Mouth.

Southern zone - The taking of lobster is prohibited between 6:00pm 30^th of April and 6:00am 1^st October (roughly from the mouth of the River Murray to the Victorian border).

Northern zone - The taking of lobster is prohibited between 6:00pm 31^st of May and 12:00 noon 1^st November (the area west of the southern zone, including Kangaroo Island).

Apart from these seasonal closures, there are rock lobster sanctuaries where rock lobsters are totally protected at all times. These are:

• Cape Jaffa
• Margaret Brock Reef (within 0.55 nautical miles of the light)
• Rivoli Bay, including Penguin Island (from Glen Point to Cape Martin)
• Gleasons Landing
• All aquatic reserves / marine parks

Rock lobster taken by recreational fishers must have the middle tail fan clipped before landing. This should be done using scissors. Failure to clip the middle tail fan may result in prosecution with a maximum penalty of $2000. Fisheries Officers must be able to distinguish between commercial and recreational catches. Recreational catches cannot be sold.

Legal Minimum Length

• It is an offence to spear Southern rock lobster.
• It is an offence to take berried female Southern rock lobster.
• The middle tail fan must be cut before landing Southern rock lobster. Speak to your nearest fisheries office to see how this is done correctly.
• A size limit of 10.5cm carapace length applies in the Northern Zone Rock Lobster Fishery (NZRLF).
• A size limit of 9.85cm carapace length applies in the Southern Zone Rock Lobster Fishery (SZRLF).
• The taking of Southern rock lobster is prohibited between 6.00pm on the 31^st May and 12 noon on the 1^st November in the Northern Zone Rock Lobster Fishery (NZRLF).
• The taking of Southern rock lobster is prohibited between 6.00pm on the 30^th April and 6.00am on the 1^st October in the Southern Zone Rock Lobster Fishery (SZRLF).

Bag Limit

A daily bag limit of 4 per person applies. A daily boat limit of 8 per boat applies.

Berley Mix

Not really required.

Rigs Used

Devices except those held in the hand, must have a tag bearing the users name and address. Tags must be made of plastic, metal, wood or some other material durable in water. They should have minimum dimensions of 10 cm x 5 cm, and should show the required markings in lettering, which is at least 2 cm in height.

Buoys used in the River Murray and Lake Alexandrina to mark yabbie pots must be durable in water, have a volume not less then two litres and be white in colour.

The following are permitted devices commonly used to catch rock lobster.

Rock Lobster Pot Maximum width: 1.5m Maximum height: 1.2m The mouth of the pot must be at the top.  A pot must be covered by mesh not less than 50mm, or have two escape gaps, on opposite sides, and of minimum dimensions 15 cm wide by 5.5 cm high.  Each rock lobster pot must be marked with a red buoy and a tag with the registered owner's name, address and registration number. Maximum 2 rock lobster pots per person, which must be registered.

Drop Net Two hoops joined by a cylindrical or cone-shaped net bag. Maximum hoop diameter: 107 cm The drop net must be marked with a white buoy and a tag showing the owner's name and address if unattended. Maximum of 3 drop nets per person.

Hoop Net A net attached to a hoop. May not be used in a commercial fishing reach. Maximum hoop diameter: 107 cm Maximum depth of net bay: 92 cm Maximum of 3 hoop nets per person. Must be marked with a white buoy and tag showing the owner's name and address if unattended.

It is illegal for recreational fishers to sell their catch.

If you are using rock lobster pots OR hoop nets OR drop nets, you are not entitled to use any other fishing equipment other than a fishing rod or handline.

• Rock lobster pots can only be used by the holder of a current registration.
• You may use up to 2 pots OR 3 drop nets OR 3 hoop nets at a time. You may not take rock lobster with pots from a boat if the boat has been used on the same day for setting, lifting or attending 3 pots.
• Rock lobster pots, drop nets, and hoop nets must conform to the legal specifications as mentioned above.
• Corfs or holding cages for keeping lobster alive in the water are prohibited throughout the State.
• It is an offence to take or attempt to take rock lobster using a spear, hook or other pointed instrument.

New changes relevant to the taking of rock lobster from 1^st December 1997:

• A bag limit of 4 rock lobster per person per day (regardless of how taken).
• A boat limit of 8 rock lobster per boat per day, regardless of how many persons are on board.
• The use of corfs to keep rock lobster alive in the water is prohibited.
• Any lobster taken, regardless of method, must have the middle tail fan cut off before landing.
• A snare is now a permitted device.

Further changes relevant to access to the rock lobster fishery by recreational fishers may be expected.