Biology of a translocated population of the large freshwater crayfish, Cherax Cainii Austin & Ryan, 2002 in a Western Australian river
Beatty, S.J., Morgan, D.L. and Gill, H.S. (2004) Biology of a translocated population of the large freshwater crayfish, Cherax Cainii Austin & Ryan, 2002 in a Western Australian river. Crustaceana, 77 (11). pp. 1329-1351.
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A population of the large, recreationally important marron, Cherax cainii, translocated outside its range into the Hutt River, Western Australia was sampled monthly between January and December 2001 and the length at first maturity, gonadal development, spawning period, and growth and mortality rates for the different sexes were determined. Female C. cainii were found to mature at a considerably larger size in the Hutt River, the northernmost population in this state, compared with other riverine and most reservoir populations occupying more southerly (higher latitude), cooler habitats. The orbital carapace length (OCL) at which 50% of the females matured (L50) was estimated to be ~70 mm, cf. ~32 mm OCL reported from a population near the centre of its range. The modified Von Bertalanffy growth functions, which incorporated seasonal oscillation in growth, were not different between sexes and the curve of pooled sexes had a growth coefficient (K) of 0.42 and an asymptotic orbital carapace length (Linfin) of 101.9 mm. The L50s for females (~70 mm OCL) and males (~40 mm OCL) equated to ages of ~36 and ~16 months, respectively. Based on the temporal patterns of gonadal development and gonadosomatic indices, C. cainii underwent a single spawning event between July and September, which was earlier than southerly populations. The spawning rate of C. cainii in the Hutt River was relatively low compared with that recorded from within its natural range. It is proposed that the much larger length at first maturity and low spawning rate in the Hutt River were due to faster growth rates caused by relatively high water temperatures and in response to competition with another introduced crayfish, Cherax destructor, respectively. This study highlights the plasticity of the biology of C. cainii and has considerable implications for effective management of the size-regulated recreational fishery.
|Publication Type:||Journal Article|
|Murdoch Affiliation:||Centre for Fish and Fisheries Research|
School of Veterinary and Biomedical Sciences
|Publisher:||Brill Academic Publishers|
|Copyright:||2004 Brill Academic Publishers|
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