Embryonic development of a mountainous fish species Garra cambodgiensis (Tirant, 1883) in southern Thailand

Abstract

This study examined the artificial breeding and embryonic development of a mountainous fish species Garra cambodgiensis (Tirant, 1883) found in Promlok waterfall in Khaoluang National park, Phromkhiri district, Nakhon Si Thammarat province. The fishes were collected from June 2017-January 2018 and kept in aquaria. Afterward, the brood males and females were selected and injected with buserelin (LHRHa) (10 µg/kg body weight) and domperidone (10 mg/kg body weight). After the injections, both females and males were kept together in the water at a proportion of 3 females: 1 male. The fertilization of eggs started after 4 hours and 30 minutes. The fertilized eggs were greenish-grey and semibuoyant. After fertilization, one blastodisc turned into 2 equalsized blastomeres, and then each cell divided into 4, 8, 16, 32, 64 cells respectively. The morula stage went to the blastula stage in about 3hr and 28 min, to gastrula stage in about 5 hr and 11 min, and to the somite stage in about 7 hr and 7 min. The optical vesicles and auditory vesicles developed after approximately 8 hr and 27 min, and 10 hr and 30 min, respectively. After approximately 12 hours and 58 minutes of fertilization, hatching of eggs occurred. Nowadays, the numbers of G. Cambodgienesis are declining rapidly in southern Thailand due to several environmental and anthropogenic reasons. Therefore, it is very important to conserve the populations of G. Cambodgienesis. Artificial breeding could be an effective way to conserve and restore this fish in their natural habitat in southern Thailand.