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Predictive equations for managing semi‐intensive grow‐out of a freshwater crayfish (marron), Cherax tenuimanus (Smith 1912) (Decapoda: Parastacidae), on a commercial farm
Author(s) -
Morrissy N M,
Walker P,
Moore W
Publication year - 1995
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.1995.tb00862.x
Subject(s) - crayfish , stocking , biology , zoology , decapoda , biomass (ecology) , fishery , ecology , crustacean
Stocking and harvest data from 45 grow‐outs of the crayfish Cherax tenuimanus (Smith 1912) on a commercial farm were analysed to give predictive equations for survival, mean weight and individual weights of crayfish at harvest. Density dependence was a major factor influencing variation in survival and mean weight. Harvest mean weight decreased, and biomass increased, with density. The crayfish price ($ kg −1 ) employed to estimate the market value of harvested crayfish increased with individual weight from a minimum saleable weight of 40 g. For grow‐out of 0+ year‐olds for 1 year, the market value was a maximum at low stocking densities of 1.5‐2.0 m −2 . Further grow‐out for 1 year of the unsaleable weight range (20‐40 g) of 1+ year‐olds, gave a harvest value which increased with stocking density. Comparison of predicted and actual cohort numbers and mean weights for a further 1 5 harvests showed no bias in prediction and a mean precision level of 16% for numbers and 11% for mean weight.