Generation of viable progeny from dead brooders of endangered catfish Clarias magur (Hamilton, 1822)

Abstract

The obligatory air-breathing catfish Clarias magur is a prime candidate for aquaculture owing to its unique taste, high growth rate, and hardy nature. However, recently the IUCN has listed the species under the endangered category because the population has critically declined in the wild. The sexually mature C. magur brooders are often collected from their natural habitats for seed production in captivity. In many cases, the brooder dies due to handling injuries or confinement stress. In this study, we demonstrated that viable progeny could be generated from freshly dead sexually mature C. magur. Three hours after death, the gonads were excised, macroscopically examined and gamete viability was evaluated. Artificial fertilization was performed by mixing the sperm suspension with the eggs. Water was added after 1 min of mixing to activate the fertilization process. We observed 85%-93% fertilization success from gametes derived from dead donors as opposed to 90%-95% from those derived from live control donors. The embryos showed normal development and resulted in the generation of 88%-92% viable progeny, which was similar to the progeny derived from control donors (92%-93%). The results obtained in this study will have profound implications in enhancing the seed production of endangered C. magur and could potentially be applied to other key commercially or endangered fish species.

The modulation effects of dietary zinc on reproductive performance and gonadotropins’ (FSH and LH) expression in threatened Asian catfish, Clarias magur (Hamilton, 1822) broodfish

“…The IUCN has listed C . magur under threatened species with overexploitation, and due to introduction of alien species such as Clarias gariepinus (Roy et al, 2019) and without management strategies the stock might further decline (Majhi & Kumar, 2017). The bottlenecks for seed production are constraints of captive breeding (Sahoo et al, 2010), and the male fish have to be sacrificed for milt release from seminal vesicles despite GnRH induction (Ahmad et al, 2018).…”