Development of breeding and fingerling production techniques for endangered long-whiskered catfish Sperata aor in captivity

An experiment was undertaken to develop a suitable seed production technique for Sperata aor in captivity. Naturally produced fry of aor was reared at different densities in nine nursery ponds ۰.۰۱۲ ha in size with an average depth of ۰.۸ m each. Three stocking densities tested, each of which was triplicated. Fry of aor stocked at ۱۰۰,۰۰۰/ha was designated as treatment-۱ (T۱), ۱۵۰,۰۰۰/ha as treatment-۲ (T۲) and ۲۰۰,۰۰۰/ha as treatment-۳ (T۳). All stocked fry were from the same age group with mean length and weight of ۱.۷۸ ± ۰.۲۸ cm and ۰.۲۴ ± ۰.۰۵ g, respectively. Fry in all the treatments were fed with SABINCO nursery feed (۳۲.۰۶% crude protein) for the first ۱۴ days and starter-I (۳۱.۵۳% crude protein) for days ۱۵ to ۵۶. Physico-chemical parameters and plankton population of pond water were within the optimal level being better in T۱ than those in T۲ and T۳. Growth in terms of final weight and length, weight and length gain, specific growth rate, daily growth rate, and survival of fingerlings were significantly higher in T۱ followed by T۲ and T۳. Food conversion rate was significantly lower in T۱ than in T۲ and T۳. Significantly higher number of fingerlings was produced in T۳ than those in T۲ and T۱. Despite this, consistently higher net benefits were achieved from T۱ than from T۲ and T۳. This is the first time report that stocking of ۱۰۰,۰۰۰ fry/ha appears to be the most suitable density for rearing of aor fingerlings in nursery ponds.

Keywords:

Sperata aor , Fry , Stocking density , Fingerling , Growth , Production