Pilot-scale spawning and fry production of blue-fin porgy, Sparidentex hasta (Valenciennes), in Kuwait

Husbandry and spawning performance of blue-fin porgy broodstock, Sparidente x hasta (Valenciennes), are described. Both wild broodstock (fish caught fr om the sea and domesticated in tanks) and cultured broodstock (from hatcher y-produced fry grown in tanks) spawned spontaneously in large concrete or f iberglass tanks (30-90 m(3)) during February-April 1987. About 88 million e ggs were collected from spawning 36 female and 32 male broodstock of 4-7 ye ars old. A total of 61.3% of the collected eggs were floating (viable) eggs . Average hatching rate of the floating eggs was 78.8%. Larval rearing and fry production procedures for the blue-fin porgy are presented. An average production rate of 2760 fry (0.3 g each)/m(3) (range. 1960-3470 fry/m(3)) w ith normal swim bladder inflation was achieved from a pilot larval and fry production trial, which was carried out in ten to twenty 4-m(3) circular fi berglass tanks. Average survival rate of the 60-day old fry was 10.2% (rang e: 8.9%-12.3%) at an average initial density of 57 hatched larvae/l. Initia l swim bladder inflation rates for la-day old larvae ranged from 64% to 93% (average, 83%) but increased to an average of 95% for 60-day old fry. Crit ical stages where high larval mortalities occurred are described. Several m odifications were made to the previous larval rearing and fry production pr ocedures in terms of feeding regime and illumination. The modifications may have contributed to the better larval survival and fry production rates as well as higher initial swim bladder rates compared to previous results. (C ) 1999 Elsevier Science B.V. All rights reserved.