The present study was carried out to evaluate the toxic effect of Chloroxuron (a weedicide) on histopathological changes in the liver of a fresh water teleostean fish, Mystus tengara (Ham.) at sublethal concentrations (0.75 and 0.85 ppm) for 10 and 20 days. After such treatment the liver showed disintegration of hepatic cells, separation of the hepatic cells from the blood vessels and proliferation in the pancreatic tissues with broken blood vessels and atrophy in the nucleus of hepatic cells with broken hepatic cells as compared to control. The details have been discussed in this paper.
Studies on cyclic changes (for 12 months) in aquatic, aerial and total oxygen uptake in a fresh water air breathing fish, Channa marulius (Ham.) were made which showed wide range of variations in different months of the year. It ranged from a minimum value of 0.838, 0.283 and 1.121 m102/h in December to a maximum value of 2.888, 2.363 and 5.251 m102/h respectively in the month of June. Statistically significant correlation was observed between seasonal variations in oxygen uptake and seasonal changes in ambient water temperature but the points on a plot gave good fit to two regression lines, inflection at the meeting point of the two regression line was observed at 29.20C in this fish. The details have been discussed in this paper.
Studies of metabolic rate (bimodal oxygen uptake) have been studied in an air breathing fresh water fish, Channa marulius (Ham.). Aquatic, aerial and total oxygen uptake per unit time (m102/h) in Channa marulius ranged from 0.963 to 5.213, 0.666 to 3.313 and 1.623 to 8.526 respectively within the weight range 9.52 to 95.0g. Statistical analysis of the data reveals that with unit increased in body weight, aquatic, aerial and total oxygen uptake in this fish increased by a fractional power of 0.8309, 0.7229 and 0.7737 respectively. Aquatic, aerial and total 02 uptake per unit body weight (cc/kg/b) decreased by a fractional power of -0.1910, -0.2796 and -0.2302 respectively. The percentage of aquatic : aerial oxygen uptake in this fish were 60.62: 40.38. The details have been discussed in this paper.