Haematology is the subject, which deals with the study of blood and embraces various aspects of physio pathological as well as the biochemical characteristics of the blood. Fish haematology is one of the most recent branches of physiology to assess the status of general health. In the last three decades fish blood study has become an increasingly important tool for fishery biologists and ichthyologists for regular monitoring of health of the fish stocks and to develop an information database about inter-specific and intra-specific variations in blood characteristics under varying environmental conditions and stages of life From the Study it is evident that the number of erythrocytes in fish exposed to zinc was significantly decreased in group exposure as compared to control fish. The percentage of alteration was 18.8. In individual exposure, all the four fish showed significant increase, which varied from 14.2% to 20.7%. The number of erythrocytes in group exposure fishes exposed to cadmium was significantly elevated. The percentage of alteration was 13.2 as compared to control fish. Individually exposed fishes also showed significant increase which varied from 12.3% to 16.1%. The number of erythrocytes in group exposure fishes exposed to copper was significantly increased as compared to control fish. The percentage of alteration was 43.4%. In individual exposure, all the four fishes showed significant increase which varied from 37.7% to 46.2%. In the present study monocytes decreased in all the exposures, except zinc. Monocytes were less frequent than the large lymphocytes. The number of lymphocytes decreased in cadmium. Lymphocytes are the second frequent type of leucocytes present in peripheral blood. In the present study, the observed number of lymphocytes (22.3%) is supported by the findings of Rani and Rao (1979) who reported 6.8% large lymphocytes and 30.5% small lymphocytes in Elops saurus. In the present study lymphocytes number increased from 22.2% in control to 27.7% on exposure to zinc.
Haematology, Cadmium, Cadmium, Copper, Blood. TLC, TEC, Fish, Channa punctatus.
