Reducing cannibalism of narrow clawed crayfish Astacus leptodactylus Eschscholtz 1823 through management of photoperiod and stocking density

In crayfish hatcheries, one of the main factors affecting reproduction operation is survival and cannibalism of brood stock. One of the main problems for expansion of Astacus leptodactylus Eschscholtz 1823 production is high mortality and cannibalism of broodstock during the reproduction operation. The effect of photoperiod and stocking density on cannibalism, moulting and survival of A. leptodactylus was examined in the context of broodstock husbandry. Cannibalism was lowest and survival highest when crayfish were housed at low density (10.m^-2) and with longer photoperiod. The longest photoperiod, 18 h light (L): 6 h dark (D) conditions resulted in high survival with minor cannibalism. Longest photoperiod also had the undesirable outcome of lower frequency of moulting, suggesting possible impacts on growth.