Recent advances in Seriola dumerilli culture

Abstract

The present study summarizes recent advances in broodstock management and larval rearing of greater amberjack S. dumerilli. At present, the major commercial aquaculture interest with Seriola species is focus on four species: greater amberjack S. dumerili (Risso, 1810), Japanese amberjack S. quinqueradiata (Temminck y Schlegel, 1845), yellowtail amberjack S. lalandi, (Valenciennes, 1833), and longfin yellowtail S. rivoliana (Valenciennes, 1833). The greater amberjack is the preferred species of this genus for aquaculture diversification in the Mediterranean and Atlantic regions in UE. Accordingly, a significant number of studies have been published in relation to reproductive biology, broodstock management and hormonal manipulation to obtain spawns. Despite some authors have occasionally obtained gonadal maturation and spontaneous spawns in this species, frequently final ovary maturation is inhibited in captivity. In the present several aspects of broodstock management and hormonal induction resulted in obtaining large number of spawns with high quality that would provide reliable numbers of juveniles for the sustainable development of great amberjack culture. The results showed that intramuscular injections of 20 µg. kg-1body weight GnRHa, in fluent males and females maintained under natural temperature and photoperiod conditions in the Canary Islands produced a high induction efficiency. Thus, the number of spawns (22) and female fecundity (2.48 millions eggs/female/spawning season) were similar to those of free wild populations and higher than those previously obtained in captivity for this species. Besides, with the exception of the two first spawns, spawn quality was very good (98.92% fertilized eggs, 92.58% hatched eggs, 68.31% larval survival), being higher than those obtained until present for this species. In addition, eggs obtained from hormonally induced spawns were utilized to to perform different larval rearing trials either in semi-intensive (SIS: 4.5 eggs.l-1 in 40m3tanks) or intensive (IS:75 eggs l-1 in 2m3 tanks) culture systems. In addition, first studies to established essential fatty acid requirements at Artemia feeding stage were conducted. An average hatching rate of 77.7±37.7 was obtained. While larval survival at 30dah was significantly improved with the use of semi-intensive conditions, reaching 25.8%, while either increase in DHA and EPA content in Artemia enrichment was positively correlated with larval survival, and growth. Additionally, major problems at weaning phase and pre- growing will be addressed.