The Murray crayfish (Euastacus armatus) is a large freshwater crayfish endemic to southeastern Australia. It grows to about 30 centimeters long (though larger examples were recorded in the past) and has white claws and a dark brown, gray, or olive-green carapace, covered in robust spikes. Murray crayfish are also referred to as “crays,” “spinies,” or simply “lobsters.” They live in cool, fast-flowing water and like deep pools and areas with plenty of boulders, sunken logs and branches, and other natural debris. They burrow in the riverbank and are most active during the cooler part of the year, from May to October. Murray crayfish are found at various elevations in the Murray and Murrumbidgee rivers and many of their tributaries. They feed primarily on plant matter but also eat dead animals. It takes 6 years or more for Murray crayfish to reach reproductive age.
The Murray crayfish has been a traditional food source—as well as an indicator of river health—for Aboriginal peoples living along the rivers of southeastern Australia for thousands of years. In some cultures it is considered a delicacy. Several traditional methods were used to catch crayfish: If the water was low enough, they could simply be collected by hand, while in deeper water they were caught in woven traps baited with meat or pulled from their burrows by divers (often women). They could also be speared. Once caught, the crayfish were cooked in the hot coals of a campfire or in earth ovens.
In recent decades the range, abundance, and average size of Murray crayfish have declined. This is due to a combination of factors, including the alteration of river flow and temperature; pesticide runoff from intensively farmed areas; habitat degradation from sedimentation and clearing of riparian vegetation; the introduction of non-native crayfish species; and overfishing. Murray crayfish are listed as vulnerable or endangered in some regions, and may be locally extinct in the lowest reaches of the Murray River. Several measures have been put in place to protect this species, including fishing seasons (they can only be harvested from May to August) and limits on the number of crayfish that may be harvested at any one time, and on the size of crayfish that may be taken (small individuals should not be harvested). Females carrying eggs cannot be harvested, and in some areas there is a complete ban on collecting Murray crayfish. There are also regulations regarding the types of fishing equipment that can be used.
Because of their slow growth rate, low meat yield, and water quality requirements, Murray crayfish are not suitable for aquaculture, and commercial fishing for this species stopped in the 1980s in New South Wales. Fishing for Murray crays remains a popular recreational activity in Victoria and New South Wales. They are often boiled in salted water, though any preparation suitable for lobster will work for Murray crayfish.