Larval Development and Rearing of Longtooth Grouper Epinephelus bruneus in Jeju Island, Korea

Abstract

Eggs and sperm were obtained from a female (6.3 kg/BW) and a male (8.4 kg/BW) longtooth grouper Epinephelus bruneus following HCG injection in July 2003. The eggs were fertilized artMcially with the sperm and incubated in one of two 50‐m3 tanks after washing the fertilized eggs. The fertilized eggs were 830–950 pn (average 900 ± 2 μm) in diameter and the respective fertilization and hatching rates were 97.7 ± 0.6% and 96.8 ± 0.5% at a water temperature of 25.0 ± 0.5 C. With this regime, the survival rate by day 93 was 7.5% in the 50‐m3 tank. The elapsed time from hatching to opening the mouth was 3 d at 25 C. The initial mouth size (z) of the larvae was 0.22–0.23 mm. The newly hatched larvae were 2.02 ± 0.02 mm TL; this increased to 4.12 ± 0.09 mm TL by day 11. By day 54, the larvae had metamorphosed into juveniles and reached 41.12 ± 1.20 mm TL, and by day 93 the juveniles reached 93.78 ± 1.98 mm TL. In all, 49.5% of the larvae were malformed and the type of malformation was diverse.

Shrinking baseline: the growth in juvenile fisheries, with the Hong Kong grouper fishery as a case study

“…Although yellow grouper and longtooth grouper can be raised in hatcheries experimentally, this is not believed to occur at commercial levels (Sawada et al. 1999; Hong and Zhang 2002; Song et al. 2005).…”

“…All other species were considered to consist of wild-caught fish inclusive of those that were taken from the wild as juveniles and grown out to adult size. Although yellow grouper and longtooth grouper can be raised in hatcheries experimentally, this is not believed to occur at commercial levels (Sawada et al 1999;Hong and Zhang 2002;Song et al 2005).…”

Induced maturation and fertilized egg production of the red‐spotted grouper, Epinephelus akaara , using adaptive physiology of photoperiod and water temperature

“…The success of hormone treatment to ovulation highly depends on the type of hormone, the administration method and the maturational stage of broodstock (Rasines et al, ). The most common method to stimulate gonad maturation, ovulation, and spermiation in cultured fish is the exogenous treatment with HCG and gonadotropin‐releasing hormones agonists (GnRHa) (Kim, Lee, & Lee, ; Mylonas, Fostier, & Zanuy, ; Mylonas & Zohar, , ; Song et al, , ). HCG induction of final oocyte maturation and ovulation has been used successfully on groupers at dose levels from 500 to 4,000 IU/kg in the natural spawning season.…”

Development of microsatellite markers for the kelp grouper Epinephelus bruneus by 454 pyrosequencing and transfer to related species

“…The other problem is that the survival of artificially reared larvae has remained low because of the high mortality rate at early developmental stages (Hirata et al, 2009). In Korea, the artificial seed production technique has been investigated since 1993, and small-scale seed production has been established since 2005 (Song et al, 2005;Lee et al, 2008). In addition, juvenile seedlings are being released for resource restoration.…”

“…Despite recent success in the small-scale production of larvae and juveniles, the aquaculture of E. bruneus in Korea and other countries remains problematic because of the high mortality during the early life stages of artificially reared larvae (Sawada et al, 1999;Song et al, 2005).…”