Advancing sexual maturation and induced breeding of a minor carp, Labeo gonius (Hamilton, 1822) (Teleostei : Cyprinidae) by impact of artificially enhanced temperature and photoperiod in Assam

摘要

Inadequate ambient temperature along with short photoperiod, during five winter months (November to March)is one of the major hindrances in development of aquaculture sector in the NE region of India, which besides hampering ingrowth and production of fish also cause mismatching in between culture period and availability of stocking material, leadingto poor performance of the available culture resources. To address this issue, a study on the impact of artificially enhancedtemperature and photoperiod during winter months on sexual maturation and breeding of cultivable fish species was undertakenat Fisheries Research Centre, AAU, Assam, NE India, by taking a minor carp Labeo gonius (Ham) as the test fish. The watertemperature of the experimental pond was maintained at 26±2°C during winter months (normal average temperature 14.8±8°C),by using Polyhouse made of UV stabilized LDPE film over a concrete pond and water heating system. The photoperiod wasincreased by 2.0±0.5 hours per day inside the polyhouse by artificial illumination. The results indicated that optimum watertemperature (26.0±2°C) and enhanced photoperiod during the winter months had significant positive impact by way of rapidgonadal development and early sexual maturity of the test fish. Successful induced breeding in advance (70±6 days ahead of thenormal breeding period) could be achieved in the experimental pond with 90.0±10% spawning success, 85.0±5% fertilization& 90.0±5% hatching rate. The results of the study pave the way for developing a protocol for advance breeding of different carpspecies by artificially enhancing temperature and photoperiod, thereby addressing the issue of non availability of stockingmaterial at proper time of stocking in the region.