When it was discovered that freshwater crayfish from the land “down under” grew to over a pound, aquaculturists in the United States got excited. Dubbed “freshwater lobsters,” these Australian crayfish have received a great deal of media attention.
Today Australian crayfish are reportedly farmed not only in Australia but in New Zealand, Southeast Asia, Africa, Central and South America, and the United States. Very little about the culture of Australian crayfish was known before 1975 when the selling of farm raised crayfish was first legalized in Australia.
Once crayfish farming began, aquaculture enthusiasts in Australia began investigating several different species of crayfish for their culture potential. There are more than 100 species of Australian crayfish, but only three species are presently being cultured.
These are the “marron” (Cherax tenuimanus), the “yabbie” (Cherax albidus-destructor), and the “red claw” (Cherax quadricarinatus). These three species are native to different regions of Australia and have quite distinct natural histories (Figure 1).
Marron grow to be the largest and attracted considerable interest in the U.S. during the 1980s. Research with marron has not been encouraging, however. Research has shown that this species grows relatively slowly (1 to 2 ounces per year even though they may obtain a size of several pounds) and tolerates a very narrow range of environmental conditions.
It survives water temperatures between 55 and 85o F but appears to grow best between 70 and 75o F. In its natural habitat, marron live in cool streams and rivers of southwest Australia. Summer water temperatures in most of the southeast U.S. remain at or above 85o F for two or more months each summer and may for short periods exceed 90o F.
Marron are also sensitive to handling and water quality changes. Low levels of salt (100 to 300 ppm) and moderate levels of alkalinity and hardness (50 to 100 ppm) were found to be necessary for successful growth/molting and survival. Other problems with marron are that they are difficult to breed in captivity, do not reproduce until two or three years of age, and are territorial.
Considering these factors, marron appears to be a species with limited potential in the Southeast. Yabbie, another cultured species, are native to the southeastern region of Australia. Yabbie are the smallest of the cultured Australian species, growing relatively slowly (1 1 /2 to 2 ounces per year) and only attaining a size of 1 /4 to 1 /2 pound. Yabbie are able to tolerate a wide range of environmental conditions.
The main problem with yabbie is their extensive burrowing habit. While burrowing is an important trait for crayfish that must survive extended dry periods, this trait creates problems in ponds. Yabbie have been known to cause ponds to leak or even drain by burrowing through the dam (as have native crayfish).
Because of their burrowing habits and the fact that they do not grow much larger than native American crayfish, yabbie have received little attention from aquaculturists in the U.S. Red claw, the third species, are native to remote areas of tropical northern Australia and hold the most promise for southeastern producers. Red claw have been cultured in Australia since 1985.
Research on red claw began in the U.S. about 1989, and has shown positive results: Red claw tolerate higher temperatures and relatively low dissolved oxygen concentrations. They tolerate crowded culture conditions and are considered a nonburrowing crayfish.
Red claw can grow to 2 to 4 ounces during the five to seven warmest months in the Southeast. This publication summarizes available information on the life history, environmental requirements, techniques for spawning, hatching and production, and diseases of red claw based on research in both Australia and the United States. A brief discussion is included on potential markets for red claw.
Authors:
Michael P. Masser and David B. Rouse
