Effects of photoperiod, water levels and sex on the feeding efficiency and weight increment of Mudcrabs (Scylla serrata Forskall) in a crab-fattening culture system

Abstract

A factorial experiment on the effects of photoperiod, sex, and different water levels was conducted to determine the feed efficiency, feeding behaviour, weight increment and survival percentage of mudcrabs cultured in individual and aggregate set up. Results revealed a single and interactive effects of both photoperiod and sex on weight increment and survival of mudcrabs while different water levels were insignificant to the parameters measured. Under zero photoperiod, mudcrabs exhibited less agitated movement concomitant with continuous feeding activity, indicative of the nocturnal feeding habits of the species, observed in fattening enclosure set-up. Feeding efficiency is highly significant for male crabs under zero photoperiod. Weight increment of mudcrabs attainable in 15-20 days in the usual crab-fattening practice under normal photoperiod could be possible in as early as 7-day period for crabs grown in induced dark condition (0L:24D), implicating a higher economic return in a capture-based culture system.