Aggressive interactions between three species of freshwater crayfish of the genus Cherax (Decapoda: Parastacidae)

Abstract

The freshwater crayfish, Cherax destructor Clark, native to southeastern Australia, was first introduced to farm dams in southwestern Western Australia in 1932. The geographic range of the crayfish in Western Australia has increased substantially since then, and in recent years it has become established in natural waterways where it co-occurs with species of freshwater crayfish endemic to southwestern Australia, Cherax cainii and Cherax quinquecarinatus. The potential for competitive exclusion of these endemic species by C. destructor was investigated through laboratory experiments measuring aggressive behaviour. Body mass and species were found to be important factors governing aggressive dominance between C. cainii and C. destructor, with C. cainii winning significantly more interactions only when they were larger in body mass than their opponent. In trials between C. quinquecarinatus and C. destructor of similar body mass, there was no difference between the number of interactions ‘won’ by the two species. The implications for natural populations are discussed.

Keywords:

• Crayfish
• introduced species
• aggression
• dominance
• interference competition
• Cherax

Acknowledgements

We acknowledge, with gratitude, assistance from Dr Craig Lawrence (Department of Fisheries, Government of Western Australia), and Drs Kyle Armstrong and Jane Prince (School of Animal Biology, The University of Western Australia). Funding was provided by the School of Animal Biology, The University of Western Australia. The map was compiled by Lisa Chandler (School of Animal Biology, The University of Western Australia). Dr Marilyn Bennet-Chambers is thanked for unpublished information on smooth marron.