Yabbies Health and Production Economics

Yabby Health Issues

For the protection of stocks of Western Australian native crayfish (gilgies, koonacs and marron), live crayfish may not be brought into this state from other Australian states and Territories. To preserve the disease status of existing yabby stocks in Western Australia, further unregulated introductions of yabbies into this state are not permitted. The microsporidian parasite Thelohania affects yabby and other freshwater crayfish populations in eastern states and has unfortunately become established in Western Australia. Yabbies and all other Australian crayfish are extremely susceptible to the 'crayfish plague' of the northern hemisphere (a fungal disease Aphanomyces astaci , found on American crayfish), which has devastated Europe's native crayfish populations. To guard against plague here, the importation into Australia of any species of live foreign crayfish, for whatever purpose, is not permitted.

Surface fouling on yabbies by ectocommensals, such as the protozoan Epistylis and the platyhelminth (flat worm) Temnocephala , although rarely harmful to the animals unless in extremely high densities, lowers the market appearance of affected individuals. These so-called epibionts are symptomatic of waters which are over-enriched with nutrients. Polyculture with native fish is being assessed to control these fouling organisms. A virus that affects a small percentage of yabbies has also been discovered but, as with these other diseases or ectocommensals, it poses no threat to humans.

Economics of Production

The establishment costs for farm dam production of yabbies is very low. As most farmers already have their dams for watering stock, the only equipment required are traps to catch the yabbies and containers for gill flushing and transportation. Alternatively, farmers may elect to have commercial harvesters trap their yabbies and receive a percentage of the crop value. Commercial semi-intensive pond production is much more expensive with set up and operating costs similar to those of a marron farm.

A case study of the economics of harvesting yabbies from a farmer's dams was conducted (Roe 1996), and in that year the farmer produced marketable yabbies which grossed $19,000. The study demonstrated that the farmer, who had 46 dams on the property, incurred the costs shown in tables on previous page.

After removing working costs from the $19,000 gross income for 1996 the farmer received $13,504 for the year. The farmer spent 360 hours, or approximately 7 hours per week on harvesting and feeding the yabby dams, which provided an equivalent return of $37.51/ hour of labour.

Informtation courtesy of the WA Department of Fisheries