The present work is an endeavour to study the toxicity and behavioural responses of the fish Channa punctatus (Bloch) at different concentrations of a weedicide (Aquathol or Endothal) during static acute bioassays. The TLm or LC50 values were computed to be 3.162, 2.405, 2.290 and 1.550 mg/I at 31.0±1.00C respectively for 24, 48, 72 and 96 hrs exposures of aquathol. The safe concentration value was computed to be 0.418 mg/I at this temperature. The behavioural response of Channa punctatus (Bloch) was grossly depenent on the concentration and length of exposure.
Studies on sublethal concentration of Carbofuran (a carbamate pesticde) and Ekalux EC 25 (an organophosphate pesticide) on changes in some haemato-biochemical parameters in an air breathing fish, Channa striatus (Bloch) were made. In control group of fishes, the values of blood glucose, plasma protein and blood urea were 68.92±1.23; 4.92±0.36 and 29.32±1.3 mg/100m1 of blood respectively. The exposure of fishes to sublethal concentrations of both the pesticides for 96 hrs caused significant increase in blood glucose and blood urea but significant decrease in plasma protein. The reason for such changes has been discussed in this paper
In the present work an attempt has been made to study the acute and chronic exposure of a carbamate pesticide, carbofuran on different haematological parameters in an air breathing fish Channa striatus (Bloch). Treatment of sublethal concentration (0.80 mg/I) of carbofuran caused an early increase in RBC count, Hb content and MCHC and decrease in PCV, MCV, MCH and ESR i.e. upto 96 hrs but after 10 days RBC count increased being normal on 30 days. MCV, MCH, MCHC and ESR showed decreasing trend. Recovery studies were also conducted. The details have been discussed in this paper.
In the present work an attempt has been made to find out the variations in biochemical composition and calorific values in an air breathing fish Channa punctatus (Bloch) under chronic exposure of different pesticides and their combinations besides assessing whether or not the obtained data also can be used as an indicator for assessing water quality and its management.
Studies on the effect of Phosalone (an organophosphate pesticide) on histochemical changes in gills were made in a snake headed murre/ fish, Channa gachua (Ham. ). In the gills of control fish – Bromophenol blue test (for general protein), Alcian blue test (for acid mucosubstances) and PAS test (for carbohydrate substances) exhibited strong reaction both in the cartilagenous part of the gill arch and in the primary gill lame/lae. In phosalone treated fishes, their gills showed reduction in staining property (showing weak reaction) though there was difference in the staining intensities in acidophil cells, mucous cells, epithelial cells and central column of secondary gill lame/lae. The reason for such changes have been discussed in this paper.
Studies or the effect of phosalone (an organophosphate) on changes in haematological indices were made in a snake headed murrel fish, Channa gachua (Ham.). The mean values of Hb content, RBC count, Haemalocrit values, M.C.H.C. and Oxygen capacity in control group of fishes were 15.2+0.18 (g%), 2.86+0.11 (million cells/mm of blood), 23.8+1.18, 63.8 (%) and 19.0 (Vol%) respectively. Treatment of acute sub lethal dosage (8.0 ppm) of phosalone brought statistically significant decrease in most of the blood parameters except M.C.H.C. in experimental animals. The reason for such changes has been discussed in this paper.