Distribution and abundance of fish populations in Harike wetland-A Ramsar site in India.

Harike wetland was declared a Ramsar site in 1990. It is located at the confluence of two major rivers of Indus rivers system, the Beas and the Sutlej, but was never explored extensively for its existing fish biodiversity. Earlier only 27 fish species of commercial value were reported from the wetland. Acknowledging its importance for rich diversity, fish assemblages in seven different reaches of Harike wetland were studied to determine their abundance and distribution. 61 fish species of 35 genera were recorded from Harike wetland during the present study. Cirrihinus mrigala and Cyprinus carpio belonging to family Cyprinidae were the dominant fish species. Lake and Riyasat having many microhabitats supported highest diversity of fishes (60 and 56 respectively) followed by Beas (20) Sutlej (14), Confluence (12), Reservoir (9) and Downstream (8). Among the IUCN designated threatened species, 1 Critically Endangered, 4 Endangered and 13 Vulnerable fish species of India are found in Harike wetland. Species diversity index, dominance, evenness and catch per unit effort were calculated to ascertain the fish distribution in Harike wetland.

Age and growth patterns in Channa marulius from Harike Wetland (A Ramsar site), Punjab, India.

Scale samples of Channa marulius were collected and studied for age determination and calculation of growth parameters. The fish were sampled from Harike Wetland during 1998 to 1999. Linear relationship with a high degree of correlation was observed between total fish length and the lateral scale radius. Age determination studies revealed 5 age groups. The harvestable size falls just below the 2nd year. The regression equation is given. Various growth parameters indicate a hardy nature of the fish and the suitability of habitat ecology for its optimum growth.

Mercury induced architectural alterations in the gill surface of a fresh water fish, Channa punctatus.

An air-breathing fresh waterfish Channa punctatus was exposed chronically to sublethal concentrations of mercuric chloride and the respiratory surface was found to exhibit lesions, lifting of lamellar epithelium and increased number of mucus gland openings. The damage increased with increase in the concentrations. The gill surface was studied using scanning electron microscope.