Embryonic and larval development of a hybrid between kelp grouper Epinephelus moara ♀ × giant grouper E. lanceolatus ♂ using cryopreserved sperm

Abstract

Hybridization was used to take advantage of desirable traits in offspring. In the present study, we applied the cryopreserved Epinephelus lanceolatus sperm into interspecific hybridization with E. moara. Successful hybridization between these two species was achieved and cultured in 23–24°C seawater (34‰). There was no difference in survival rate between hybrid (E. moara ♀ × E. lanceolatus ♂) and non‐hybrid (E. moara ♀ × E. moara ♂) at 24 hrs post hatch (HPH), but less hybrid (14.35 ± 8.02%) hatched than non‐hybrid (93.60 ± 1.65%), which might be due to irregularity cell cleavage and skeletal deformities from the formation of embryonic body to the later embryonic development. Similar phenomenon was found in hybrid embryos from fertilization with fresh sperm, indicating that species variations between parents, rather than cryopreserved sperm, resulted in deformities in embryos. Mean hatch time of the hybrid was 1 hr faster than that of E. moara. The hybrid was 1.95 ± 0.06 mm in total length when newly hatched and reached 38.00 mm at 58 days post hatch (DPH), which showed faster growth than E. moara (recorded in the previous study). Considering its faster growth, E. moara × E. lanceolatus hybrid was a potential breeding production in aquaculture. Over 212,000,000 larvae have been produced and launched in the market since 2015. The results of this study also shed some lights on further comparative studies in grouper hybrid performance.

Embryonic development and hatchability of red‐spotted grouper ( Epinephelus akaara ) ♀ × giant grouper ( E. lanceolatus ) ♂ hybrid at three incubation temperatures

“…The hatching time of RGGG was 27 hr 55 m ± 01 hr 45 m at 25°C, which was approximately 1 hr slower than that of RG (26 hr 57 m ± 00 hr 54 m; p > 0.05, Table ). According to previous studies, the hatching time of dusky grouper ♀ × white grouper ♂ and kelp grouper ♀ × giant grouper ♂ were 5 and 1 hr faster than that of the maternal species, respectively (Chen et al, ; Glamuzina et al, ). The hatching time of orange‐spotted grouper ( E. coioides ) ♀ × giant grouper ♂ did not differ from that of the maternal species (Kiriyakit et al, ).…”

“…In previous studies, the fertilization rate and hatching rate of goldblotch grouper ♀ × dusky grouper ♂ and dusky grouper ♀ × white grouper ♂ did not differ from those of the maternal species (Glamuzina et al, ; Kiriyakit et al, ), exhibiting the same tendency observed in this study. In contrast, the hatching rate of kelp grouper ♀ × giant grouper ♂ was 4.49%, which was significantly lower than that of the maternal species (64.35%; Chen et al, ).…”

“…The deformity rate of hatched larvae was 22% in goldblotch grouper ♀ × dusky grouper ♂ and 25% in dusky grouper ♀ × white grouper ♂ (Glamuzina, ; ). The deformity rate of newly hatched larvae was 85%–90% in kelp grouper ♀ × giant grouper ♂ (Chen et al, ).…”

“…Recently, hybridization between groupers with different preferred natural habitat temperatures has been induced. Hybridization between kelp grouper ( E. moara ; 17.7°C–23.7°C, mean 20.5°C) and giant grouper (24.3°C–29.1°C, mean 28.1°C, Kaschner et al, ) has been induced, but the hatching rate was very low at temperatures of 23°C–24°C (Chen et al, ).…”

“…The deformity rate of hatched larvae was 22% in goldblotch grouper ♀ × dusky grouper ♂ and 25% in dusky grouper ♀ × white grouper ♂(Glamuzina, 1999;. The deformity rate of newly hatched larvae was 85%-90% in kelp grouper ♀ × giant grouper ♂(Chen et al, 2018).Studies have been conducted on the correlation between incubation temperature and embryonic development in pure grouper species (Gracia-López,Rodríguez-Romero, & Pérez-Ramírez, 2004;…”