Substrate selection and effect of different substrates on survival and growth of juveniles of the freshwater crayfish Cherax quadricarinatus (von Martens 1868) (Decapoda, Parastacidae)

VIAU, V.E.; RODRÍGUEZ, E.M.

AQUACULTURE INTERNATIONAL

SPRINGER

Año: 2010 vol. 18 p. 717 - 724

0967-6120

Survival and growth of juveniles of the Australian freshwater crayfish Cheraxquadricarinatus were evaluated in aquaria with four different substrates covering theirbottom. The four substrates were plastic mesh, small stones, fine sand and bare glasswithout cover (control group). Two size classes of juveniles were evaluated: recentlyhatched or early (*0.02 g of body weight) and pre-fattening or advanced (*1g ofbody weight). A group of twelve early or ten advanced juveniles were placed in each ofthe 24 aquaria. Each substrate had a total of six aquaria, three containing early juvenilesand the other three containing advanced juveniles groups. Each aquarium had an excesssmall PVC pipes that served as shelters. After 12 weeks, early juveniles raised in smallstones or fine sand had a statistically significant heavier body mass than the controlgroup while the advanced juveniles did not show statistically significant differences inbody weight. In a second experiment, ten early and ten advanced juveniles were indi-vidually placed in a circular glass aquarium divided into four sections each containingone of the same substrates used in the first experiment. Each individual was filmed for24 h, and the time spent in each compartment was registered. Both sizes of juvenilesshowed a marked preference for the small stones. This experiment was repeated withanimals used in the first experiment and observed the same selection pattern indicatingthat substrate selection is independent of body mass or previous acclimation to thedifferent substrates.