Evaluation of reproductive performance in indigenous endemic ornamental fish Sahyadria denisonii using hormones under captive environment

Aim: The present study aimed to develop the hatchery technology for production of indigenous ornamental fish Sahyadria denisonii to ensure year round seeds and for conservation of natural resources.Methodology: In the present investigation, brooders were collected from wild, acclimatized to hatchery condition and enriched under captive environment. The mature brooders were injected with three different synthetic hormones namelyt. Human chorionic gonadotropin (HCG), Ovatide and WOVA-FH at different doses (0.3, 0.5, 0.7 and 0.9 ml/kg of female and half a dose to male). Results: Fishes did not release their gametes naturally after inducement. Hence, artificial fertilization was carried out after 16 hrs of injection. Among the synthetic hormones used WOVA-FH @ 0.5 ml kg-1 of female and half a dose to male showed better breeding performance in terms of number of spawned eggs, fertilization rate (75.3%) and hatching rate (83.0%). Interpretation: Synthetic hormone WOVA-FH, human chorionic gonadotropin (HCG) and ovatide to female and male through artificial fertilization can be adopted for captive breeding of Indigenous endemic ornamental fish Sahyadria denisonii.

Geographical distribution and evaluation of mosquito larvivorous potential of Aphanius dispar (Rüppell), a native fish of Gujarat, India.

Background & objectives: Certain indigenous fish can play potential role in vector control. The study recorded distribution of Aphanius dispar (Rüppell) in its native habitats in Gujarat, India and evaluated its larval propensity for Indian mosquito vectors. Methods: Fishes were surveyed in various districts of Gujarat and samples were collected from coastal habitats and were identified to species. Physicochemical properties of water samples were analysed in the laboratory. Five laboratory acclimatized adult fish (2.2–3 cm) released in chlorine-free water in glass jars were provided with 500 larvae daily. Five replicates were run. Daily consumption of I to IV instars of Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus was recorded separately for three days. Anopheles stephensi larval control using the fish in industrial tanks (9–180 m2) was evaluated. Results & conclusion: The fish was found in large numbers in estuarine waters, rivulets, backwaters and small dams in the districts of Kutch, Jamnagar, Patan and Anand in Gujarat. Mean daily consumption of larvae in laboratory was as follows: An. stephensi 128 ± 0.2 to 204 ± 6; Cx. quinquefasciatus 24 ± 4 to 58 ± 10; Ae. aegypti 43 ± 5 to 68 ± 2. In water tanks, A. dispar reduced 93% larval counts by Day 7 and 98% by Day 21 (p <0.01), showing high larval propensity. A consolidated information on bionomics, tolerance and physicochemical properties of water taken from natural habitats of A. dispar indicate its high larvivorous potential. Large-scale evaluation is warranted to evaluate its potential in vector-borne disease control.