Not Available

Not AvailableThe present study was aimed to assess the effect of temperatures on egg incubation, growth, standard metabolic rate (SMR), and thermal tolerance of a near threatened Himalayan hill stream chocolate mahseer (Neolissochilus hexagonolepis). For the hatching study, eggs were incubated in four temperatures (17, 20, 23, and 26 ◦C). The total hatching and free-swimming larvae percentage were higher at 23 ◦C (p < 0.05). Experiment I (for validation of the CTmax method) was carried out by incubating eggs at 17 ◦C and 23 ◦C. The CTmax was estimated in response to different warming rates (1–18◦C h 1), acclimation temperatures (17 and 23◦C), and the age of fishes (8, 15, 35 dph). The results suggested that a warming rate of 18◦C h 1 could be used for the thermal tolerance study of yolk-sac larvae (8 dph) and 35 dph larvae, but for free-swimming larvae (15 dph) up to 3◦C h 1 is suitable. Experiment II (for growth, SMR and thermal tolerance) was carried by acclimatizing 15 dph larvae in five temperatures (15, 19, 23, 27, and 31 ◦C) for 60 days. The mean growth rate increased with the increase in temperature from 15◦C to 27◦C (1.30–3.58% day 1) and decreased at 31◦C. The mean SMR of the chocolate mahseer in the above acclimation temperatures was ranged from 1.14 ± 0.36 to 2.81 ± 0.15 μgO2h 1mg 1 and were significantly different (p < 0.01). The Q10 with the SMR of the fish suggested the preferred temperature ranged between 23 and 27 ◦C, and the optimum temperature for growth (ToptG) was estimated to be 25 ◦C. Chocolate mahseer is an eurythermal species which is advantageous for aquaculture practices due to its wide thermal tolerance zone (411.68◦C2 in 15 to 31 ◦C acclimation temperature range) and high ARR values (0.49 - 0.54).Not Availabl