INVESTIGATION OF SOME REPRODUCTION PARAMETERS ON LONGFIN YELLOWTAIL (Seriola rivoliana VALENCIENNES, 1833) BROODSTOCK INDIVIDUALS, KEPT IN FARMING CONDITIONS BY CAUGHT FROM WILD  

This study aimed to clarify some reproduction parameters of longfin yellowtail (Seriola rivoliana Valenciennes, 1883) individuals, kept in farming conditions by caught from wild. In the study, among the data obtained by GnRHa hormone application, the studied ones were fecundity, batch number, sperm quality parameters and its morphology, egg quality parameters and its morphology, embryonic development stages and prelarval and postlarval morphology.

As a result of the study, the motility of male individuals (n=5) varied from %52.96±3.53 to %77.78±2.22; their motility duration changed from 864.44±65.94 sec to 1014.17±95.58 sec; and sperm density were between 60.47±8.09 and 95.36±16.22 per millilitre. The eggs of longfin yellowtail females obtained between 35 to 40 hours after the GnRHa application were 1096.61±45.30 µm in diameter and had single oil droplet of 266.15±31.43 µm in diameter. Reproduction were realised at 22.6 to 23.9 ºC in July and September period. At seventeen successful spawns, totally 6.455.480 eggs, with 99.49±0.28% fertilisation and 65.38±9.96% hatching rate were achieved. The best spawning was achieved in September. Hatching duration was between 44 and 48 hpf. Embryonic development was completed at 25 stages. The average length of newly hatched larva 2.721±0.10 mm and diameter of oil droplet was 0.336±0.02 mm.