Yabby

The image of the freshwater crayfish was sent to the Australian museum for identification. It is of the Yabby, Cherax destructor. This species was named destructor because of the damage its burrowing can cause in farm dam walls and levee banks.

Introduction

Cherax destructor is an Australian freshwater crustacean in the family Parastacidae, freshwater crayfish. Freshwater Crayfish are heavy bodied crustaceans with an enlarged, pincer-like first pair of legs. Many species occur in Australia. The Yabby, Cherax destructor, has the largest range of all Australian freshwater crayfish. It occurs across most of Victoria, western New South Wales, south-western Queensland and eastern South Australia. Other similar, smooth species of freshwater crayfish include the Koonac, Gilgy and the Marron of Western Australia, and the Red-Claw of tropical northern Australia.

Yabbies are found in many ephemeral waterways and are extremely hardy. They can survive dry conditions for many years by lying dormant in burrows sunk deep into muddy creek and swamp beds. During the wet season, they can travel kilometres across wet land in search of new waters to make home.

The Queensland Red Claw is characterised, as its name suggests, by a bright red patch on the outside of the large claw in males. The Marron is a dark purple, black or sometimes a bright blue colour. The striking blue form of the Marron is popular a aquarium pets.

Identification

• Colour is highly variable and depends on water clarity and habitat. Yabbies can range from black, blue-black, or dark brown in clear waters to light brown, green-brown, or beige in turbid waters.
• Smooth abdomen and as wide as the thorax.
• The large pincers have a mesh-like colour pattern

Distribution

Native to eastern mainland west of the Great Dividing Range, Australia, throughout the Murray-Darling system. Introduced to the Northern Territory, Western Australia, and coastal eastern New South Wales

Habitat

Freshwater ponds, farm dams, lakes, rivers and creeks .

Predators

Yabbies are an important dietary item for Platypus, water birds and Australian native freshwater fish such as Murray Cod and Golden Perch.

Economic impacts

The Yabby is a popular species for aquaculture

Management

• Yabbies can often be found on private property in farm dams, but permission to fish must first be obtained.
• Bag limits apply to Yabbies in most states. For example,N.S.W. Department of Primary Industries regulations are a bag and possession limit of 200 Yabbies per person applies when in, on or adjacent to waters or transporting or storing the Yabbies. Be sure to check local fishing regulations.
• All females carrying eggs under their tails should be returned to the water.
• Although Yabbies are at home in inland Australia, they should not be moved around or released in other waterways closer to the coast. Australia, especially the southeast, has many endemic species of freshwater crayfish in the creeks, rivers and dams on the east of the Great Divide. Several other species of native crayfish are already being severely threatened by the hardier, faster growing Yabbies that have been introduced there.