Low water temperature induces stress and affects somatic growth in teleostChanna stewartii(Perciformes)

Abstract

Channa stewartii (Playfair, 1867) belonging to Channidae family (Actinopterygii Perciformes) (http://www.fishbase.org) is a freshwater fish widely distributed in eastern Himalayan region that cover Nepal and north-eastern region of India. In India, the species is commonly known as Assamese snakehead and occurs both in running and standing water (Talwar & Jhingran 1991). Over the years, the species has been extensively exploited from natural sources to meet the anthropogenic needs, particularly in ornamental sector. Although, for sustainability reasons, the species should be propagated in mass scale but, often, the farming community of the region do not show interest to captive propagate the species due to its poor growth performance coupled with periodic mortalities in ponds and tanks (Das & Kalita 2005). One of the reasons for such poor growth rate attributes to cold climate of the region (Majhi & Das 2014). Evidently, the case of such poor growth performance do not restrict to C. stewartii lone, it’s the fate of many exotic fish fauna those were introduced to the region from elsewhere as a part of species diversification (see review by Leveque, Oberdorff, Paugy, Stiassny & Tedesco 2008). These observations have critically affected the efforts of increasing fish production in the region. Nevertheless, there are possible proven ways to overcome such practical problem. One of such strategy is culturing the fish at comparatively elevated water temperature from the ambient ranges, preferably in a controlled environment (Beitinger, Bennett & McCauley 2000; Majhi & Das 2014). It is true that water temperature, one of the important abiotic factors, control various parameters in the life span of teleost fish. For instance, the growth and reproduction of a fish could be manipulated with the increase or decrease in surrounding water temperature (Str€ ussmann & Patino 1995). It could even advance the developmental process of fish embryos (Rahman, Str€ ussmann, Majhi, Suzuki & Watanabe 2010). In the present study, we investigated (i) the growth performance of C. stewartii in low temperature (natural environment) and elevated temperature, induced by greenhouse in this case and (ii) stress-related enzymes activity in the vital tissues of the animals from both the groups to quantify the level of stress caused due to water temperature. Fish were collected using drag net of suitable mesh size from wild and brought into wet laboratory facility of ICAR fish farm located at Barapani, Meghalaya (90°55015 to 91°160 latitude and 25°400 to 25°210 longitude; 900 m >MSL). Fish were treated with 10 mg L 1 KMnO4 (Sigma, St. Louis, MO, USA) and released into a cemented cistern pool (4 9 2 9 1.5 m = 12 m) for acclimation in captivity (water temperature 25–28°C). Glass tanks (0.5 9 0.5 9 0.5 m = 1.5 m) were placed inside greenhouse (n = 3; to elevate the water temperature) and open space (n = 3; to