Breeding and Larval Rearing of Bluefin Leatherjacket, <i>Thamnaconus modestus</i> (Günther, 1877) Under Commercial Scales

Abstract

The spawning of wild caught broodstocks bluefin leatherjacket ( Thamnaconus modestus ) as well as the development of egg and larvae were studied under commercial scales. Spawning period was lasted 55 days from 15th June to 9th August, 2010. Total 4.3 million eggs were collected during the spawning period, and 65.5% of eggs were subjected to be properly hatched and developed. The diameter of the eggs was in range from 0.59mm to 0.63mm. Total 1.8 million newly hatched larva were obtained in present study with a hatching rate of 41.7%. First feeding was observed on 3 days post hatching (dph), and the yolk sac was completely exhausted on 4 dph. Metamorphosis occurred between 29 dph and 33 dph, at the total length (TL) of (11.93±2.18) mm. The growth in terms of TL can be expressed as a polynomial equation TL=3.30394-0.31862(dph)+0.02222(dph) 2 (r 2 =0.90362, n=427). After 70 days rearing, 0.3 million juveniles (TL>40 mm) were obtained and the ratio of seedling/newly hatched larvae was 5.62%. The results in this study demonstrated that bluefin leatherjacket was feasible breeding under artificial environment, and our results might provide some technical guidance for the further application in breeding this species.