005442 Rahman Q;Sadhu D N (Post Graduate Zoology Dep, Vinoba Bhave University, Hazaribag-825 301, Email: dns_hzb@yahoo.com ) : Factors affecting aerial and aquatic respiration in the air breathing fish, Channa gachua. J Ecotoxic envir Monit 2012, 22(1-2), 17-30.
An attempt has been made to study the effects off actors such as body weight, sex, ambient water temperature, pesticide and hormones on oxygen consumption in an air breathing murrel fish, Channa gachua. The oxygen consumption in C. gachua of different body weights in aquatic, aerial and total oxygen uptake was found inversely proportional to body weight. The results indicate that the male fishes consume more oxygen but females take less oxygen due to their activities and life style. In this species the oxygen uptake from water, air as well as total varied considerably with the seasonal variations of ambient water temperature. The oxygen consumption was the lowest during the month of December and gradually increased with the rise in temperature reaching at its maximum in June. Thus the nature of oxygen consumption is directly proportional to the ambient water temperature. A significant positive relationship exists between water temperature and oxygen consumption. The correlation co-efficient (r) for aquatic, aerial and total oxygen consumption was noted as 1.0, 1.0 and 1.04 at lower temperature range (21.6°- 28.2° C) and 0.943, 0.9907 and 0.9901 at higher temperature range from (28.2°-31.4° C) respectively. The effect of three different pesticides namely Metacid-50 (Organophosphate), Dithane M-45 (Carbamate) and Kelthane (Organochlorine) were studied on changes in dual mode of oxygen consumption. Exposure of fish to above noted pesticides brought significant decrease in aquatic as well as total oxygen uptake percent while it increased in oxygen consumption through aerial route as compared to control one due to the action of pesticides on respiratory muscles causing paralysis, respiratory failure and death. The treatment" of hormones i.e. Hydrocortisone (1 mg/100 g) and Thyroxine (0.5 mg/100 g) in C. gachlla brought significant increase in aquatic, aerial and total oxygen uptake was 60.8, 63.2,124.0 ml/kg/h and 53.6, 80.4, 134.0 ml/kg/h whereas Adrenaline (0.000006 mg/100 g) caused slight decrease in aquatic i.e. 51.0, 7.0,58.0 ml/kg/h but abrupt and significant fall in aerial and total oxygen consumption. The treatment of Progesterone (1mg/100 g) caused significant increase in aquatic and decrease in aerial and total oxygen uptake was 89. 3, 15.8, 105.0 ml/kg/h whereas Testosterone (2 mg/100 g) significantly increased in aquatic 84.7, 61.3, 146.0 ml/kg/h and total oxygen uptake but slight decrease in aerial oxygen uptake was noticed. Thiouracil (2 mg/100 g) increased the aquatic oxygen consumption up to 61.8, 41.2, 103:0 ml/kg/h and decreased the aerial and total oxygen consumption respectively.
1 illus, 6 tables, 55 ref
