By Vishal Gulati Chandigarh, March 12 : Fish in the rain-fed Sukhna Lake in Chandigarh is in trouble owing to man-made reasons. The lake, that supports a variety of aquatic life, makes it an abode for winter migratory birds. Now due to a variety of reasons, the delicate balance of the rain-fed lake is getting disturbed. The Department of Animal Husbandry and Fisheries is undertaking an exercise to remove old and large fish from the Sukhna Lake from March 13 to 22 to maintain its ecological balance in consultation with the Forest Department and the Zoology Department of Panjab University, Chandigarh. Biologists told IANS it is a good step towards fish conservation. They say angling, to some extent, would help removing the fish that had attained old age and stopped breeding. The lake is home to 30-odd species of fish, including Indian major carps and a few exotic carps. Every year the Fishery Department stocked Indian major carps, and exotic carps in the lake. In addition, fish from the surrounding areas are washed into the lake during floods. Experts say the trouble started after 1985 when the administration stopped auctioning of selective fishing rights in the lake. This resulted in aging of fish, which started living at the expense of the small fish, creating food and space problems for the younger breed. Environmentalists and experts have blamed the authorities concerned for this. They are worried as the lake is a feeding ground for thousands of migratory birds from far-away Siberia, Iran, Iraq and Central Europe. The annual growth rate in the first year of life in C. mrigala and L rohita is reduced to one third and half in L calbasu and C catla, according to studies conducted by the Department of Zoology of Panjab University. The administration says the aim of selective harvesting of fish is for better ecological management of Sukhna, a small lake, unlike larger water bodies with flowing water. Such lakes have their own specific requirements of ecological management of flora and fauna that are very sensitive to changes. The removal of big size fishes will also allow better feeding availability of small fishes for migratory birds, which are omnivorous in nature. The selective harvesting is being carried out on the recommendation of the Forest Department as unusual mortality was reported in last rainy season and Animal Husbandry and Fisheries Secretary Vinod P Kavle. The fishing will be conducted with gill nets of a specific mesh size not less than six cm from knot to knot so that small fishes may get protected, says the administration. The nets will be deployed at night so as to avoid public inconvenience and not interfere in recreational activities of the public. The area of fishing will be specific and will be towards the regulator end of the lake. To rejuvenate the Sukhna Lake, new fish seed will be released in consultation with experts and new varieties of fishes will be reared. A biologist told IANS there is a possibility that the present-day progeny of Indian major carps belongs to a few very old large sized carps. He favours that brooders from other streams and lakes should be introduced into the lake. He suggests that safety pits should be dug around the lake and the existing ones should be cleared from the silt so that the pits could be used by the fish during summers. Also periodic monitoring of the quality of water must be carried out. Experts feel the abiotic and biotic aspects of the lake shall be studied regularly in order to assess its productivity and carrying capacity. Also they say angling in the lake should be restarted as it is a good step towards fish conservation. They say angling, to some extent, would help in removing the fish that had attained old age and stopped breeding. (Vishal Gulati can be contacted at gulatiians@gmail.com) /IANS