Broodstock development, captive breeding and seed production of bagrid catfish, Mahanadi rita, Rita chrysea (Day, 1877)

Abstract

The present article describes about the broodstock development, induced breeding, and seed production of the Mahanadi rita, Rita chrysea, a medium-sized catfish, of the bagridae family under captive conditions. Juvenile fish collected from the Mahanadi river and raised to broodstock in the captivity and successfully breed in captive condition for the first time in India through hormonal induced breeding. Breeding performance of different broodstock size groups were evaluated to identify the suitable brooder size for successful captive breeding. Two broodstock size groups of female fish (n = 12, each group) i.e., 50–80 g and 90–130 g were selected. The female and male brood fish were induced with a synthetic hormone, Ovatide™ at 1 and 0.5 ml kg−1 body weight, respectively. All the hormone induced female brood fish were stripped for eggs 13–15 h of post-injection. The stripped eggs were fertilized with sperm suspension solution and incubated in glass jar for 24–26 h for hatching. The results revealed that the bigger sized broodstock fish group 90–130 g produced significantly higher (P < .01) number of eggs than the 50–80 g broodstock size. The total and relative fecundity of 90–130 g broodstock fish size were estimated to be 13,751 ± 619 and 12,123 ± 443, respectively. The egg quality evaluation parameters, such as fertilization rate (75.32 ± 0.71%) and hatching rate (63.88 ± 1.09%) were also significantly higher (P < .01) in the 90–130 g size brood fish. The bigger sized broodstock (90–130 g) group produced significantly higher sized eggs 1.37 ± 0.05 mm and hatchlings 4.3 ± 0.2 mm and 1.2 ± 0.3 mg compared with smaller broodstock group (50–80 g). Mahanadi rita seed production techniques were standardized through larval stocking density experiment. The larvae were stocked at different density levels to ascertain the optimum stocking density for mass scale seed production of the species in the indoor conditions. The 6-day-old larvae were stocked at different densities level, such as 2, 3, 4 and 6 numbers per litre of water. The study confirmed that 2 larvae L−1 stocking density group produced larvae with a significantly (P < .05) higher body weight gain 153.33 ± 1.88 mg and both 2 and 3 larvae L−1 density group showed significantly higher (P < .01) larval survival rate, 93.33% and 86.67 ± 2.23%, respectively.