INDUCED SPAWNING TRIALS ON PICNIC SEABREAM Acanthopagrus berda FROM INDIA
The Picnic seabream, Acanthopagrusberda (Forskkal, 1775) is an important commercial sparid fish because of its recreational value, excellent meat quality, high economic value, tolerance to wide variations in salinity and temperature, strong resistance to diseases, easy adaptation to captivity and fast growth rate. They are locally exploited by artisanal fisheries using cast net and hook & line and are sold fresh in Indian markets @ Rs.400-500/ Kg.
Broodstock of A. berda were collected from Korapuzha estuary, Calicut using cast net during the spawning season (August to December). Males and females were maintained separately in circular tanks (1000 L) and were fed with fresh squid and oyster @ 5% body weight. Female fishes weighing 650 to 1200 g and male fishes weighing 200 to 350 g were selected for injection. Males were examined for free milt. Females with more than 600 µm ova diameter were selected for inducement. A total of 28 breeding trials were conducted with different treatments (Table. 1). The inducing agents (Ovatide, HCG, LHRH, WOVA- FH) were administered either intra-muscular or intra-peritoneal, either individually or in combination.
The individual dose of WOVA FH (1.5 ml Kg−1 & 3.5 ml Kg−1) and combination of WOVA -FH (1.5 ml Kg−1) and LHRH (20 µg Kg−1) are found effective in inducing spawning in female A. berda. A. berda did not show spawning response to hCG (500 &1000 IU Kg−1), ovatide (0.5, 2.5 & 3.5 ml Kg−1) and LHRH (10 & 20 µg Kg−1). But injection of high dose of WOVA-FH, Ovatide and LHRH made the possibility of hand stripping of ova from the females after 48 hours of injection. The hand stripped ova and milt were mixed thoroughly using feather for 2 minutes and are maintained at different salinities (15, 25 and 35 ppt) and kept undisturbed for 2 hours. Fertilization was observed in all the salinity treatments. This indicates the possibility of breeding A. berda under captive conditions.
A. berda is a potential mariculture candidate species and the present study is the preliminary effort in developing a captive breeding technique for this species.
