Thermal tolerance and oxygen consumption rates of the catfish Horabagrus brachysoma (Gunther) acclimated to different temperatures

Thermal tolerance using critical thermal methodology and oxygen consumption rates of Horabagrus brachysoma (23.01 + 2.04 g) were determined after acclimating the fish to 15, 20, 26, 31, 33 and 36 degrees C temperature for 30 days. Critical thermal maxima, CTMax, (34.86 +/- 0.09, 38.05 +/- 0.06, 40.23 +/- 0.12, 41.79 +/- 0.09, 42.44 +/- 0.05, and 42.79 +/- 0.02) and critical thermal minima, CTMin, (13.17 +/- 0.09,13.56 +/- 0.05, 14.15 +/- 0.10, 15.37 +/- 0.10, 16.39 +/- 0.12, and 18.37 +/- 0.04) increased significantly (P<0.05) with increasing acclimation temperatures. A thermal tolerance polygon over the range of 15 to 36 degrees C had a calculated area of 526.6 degrees C-2. Oxygen consumption rate increased significantly (P<0.05) with increasing acclimation temperature between 15 to 31 degrees C and 33 to 36 degrees C. Maximum and minimum temperature quotients (Q(10)) were observed between 15-20 and 31-33 degrees C as 2.59 and 1.53, respectively. Final preferred temperature estimated from the Q10 value was between 31 and 33 degrees C. Results indicate that H. brachysoma has better capability for adapting to higher temperatures and suggest their culture potential in tropical regions. (C) 2009 Elsevier B.V. All rights reserved.