No abstract

A 30-day acclimation trial was conducted using Tor putitora to elucidate its thermal tolerance, oxygen consumption, haemato-biochemical variables and selected enzymatic activities at five acclimation temperatures (AT). Juveniles of T. putitora were randomly distributed among five treatment groups (20, 23, 26, 29 and 32 ± 0.5 °C). There was a significant curvilinear increase in critical thermal maxima (CT(max)) (y = -0.0693x² + 1.7927x + 34.628, R² = 0.996) and lethal thermal maxima (LT(max)) (y = -0.1493x² + 2.3407x + 35.092, R² = 0.991) with increasing AT. The oxygen consumption rate increased significantly with increasing AT. The Q₁₀ values were 1.16 between 20 and 23 °C, 3.09 between 23 and 26 °C, 1.31 between 26 and 29 °(C) and 1.76 between 29 and 32 °C of AT. The acclimation response ratios were ranged between 0.37 and 0.59. Catalase, superoxide dismutase and ATPase activities were increased linearly in liver, gill and kidney, while brain acetylcholine esterase activity decreased linearly with increasing AT. Blood glucose remained unchanged up to AT of 26 °C and increased significantly at AT of 29 and 32 °C. Haemoglobin content was increased linearly with increasing AT. The highest WBC count was observed at 20 °C, and no significant changes found till AT of 26 °C and significantly decreased at 32 °C. Total serum protein and globulin were significantly decreased with increasing AT. Highest values were observed at 20 °C and remained consistent till 26 °C, then decreased significantly. There was no significant change in A/G ratio through the AT 20-29 °C and increased significantly at 32 °C. The increase in CT(max), LT(max) and oxygen consumption rate with increasing AT may suggest that the thermal tolerance of T. putitora is dependent on its prior thermal exposure history, and it could adapt to higher AT by altering its haemato-biochemical variables.

No abstract

valid. However, a detailed description of M. tengara is lacking.In the present study, several fish specimens consistent with Hamilton's (1822) description of Mystus tengara were examined. Here we redescribe M. tengara and distinguish it from its closest congener, M. vittatus and other striped Mystus of the Ganga-Brahmaputra drainage, viz.,and M. bleekeri (Day). Materials and MethodsMeasurements were made with a dial caliper to the nearest 0.1mm. Subunits of the head are presented as proportions of head length (HL). Head length and measurements of body parts are given as proportions of standard length (SL). Methods for counts and measurements follow Ng & Dodson (1999). Numbers in parentheses following a count are the number of specimens with that count. Dorsal fin height is measured from the base of spinelet to the highest point of the dorsal fin. Twenty specimens were dissected and cleared for osteological studies. Clearing and staining of specimens follow Hollister (1934) and osteological nomenclature follows Mo (1991) and Darshan et al. (2010). Gill rakers were counted on the first left branchial