Species validation, growth, reproduction and nutritional perspective of Indian pompano, Trachinotus mookalee–A candidate species for diversification in coastal mariculture

Abstract

The Indian pompano Trachinotus mookalee can be an ideal and alternative marine candidate species for aquaculture with its cultivable traits. The study aimed to understand growth, reproductive and nutritional potentials of the fish in different culture environments and also for species validation to avoid ambiguities in further research. Wild collected broodfishes have confirmed that the species is genetically and morphologically differentiated from its four closely related species of genus Trachinotus. The studied fish growth was significantly (P < 0.05) influenced by culture environments, where the maximum growth was attained in cage (684.9 ± 14.0 g), followed by pond (564 ± 13.6 g), Recirculating Aquaculture System (RAS) (471.5 ± 10 g) and the least in indoor Fibre-reinforced plastic tank (294.65 ± 10.35 g) for 12 months of culture. Growth data indicated presence of high genetic growth potential in the species, which could be improved with suitable intervention in abiotic factors. Studied reproductive sex steroid hormone concentrations varied in the fish and were matched with the different maturity stages confirmed by gonadal development stages. The sexually mature male and female fish found with elevated levels of testosterone (2.34 ± 0.25 ng/ml) and 17-β estradiol (2.56 ± 0.95 ng/ml), respectively, which indicated that sex differences has been persisting in the species and the steroid level could act as marker in assessing the maturity status of male and female fish. The gonadal developmental stages indicated that the fish became functional male and female brooders after 26 and 29 months of culture in sea cages, respectively. Nutritional contents of the fish was significantly (P < 0.05) influenced by the culture environments. Crude protein was maximum in cage reared fish (18.96 ± 0.36%), whereas fish in RAS exhibited high crude fat (6.87 ± 1.05%). Palmitic (C16:0) and glutamic acids were the maximum abundant fatty acid and amino acid, respectively in all the cultured environments. However, the content of essential polyunsaturated fatty acids (DHA and EPA) was significantly high in wild fish. Phosphorus and iron were the maximum abundant major and micro minerals, respectively in all the culture systems. With excellent traits linked with aquaculture, the species could be the most suitable candidate for species diversification in coastal mariculture. The species deserves further studies on the basis of influence of abiotic factors on different traits.