Pollution Research Paper

FREQUENCY OF CHROMOSOMAL ABERRATION IN FISH INHABIT- ING POLLUTED ECOSYSTEM

A. OUSEPH, D. SUNDARSANAM, A.M. NAINAR AND P. GANDHEESWARI

Abstract

As a consequence of population explosion and industrialisation more than 50,000 chemicals pollutants have been produced and released into aquatic ecosystems in the last decade. Populations chronically exposed to the pollutants often exhibit variation in its morphology and karyology. River Cooum in Madras is highly polluted due to continued release of sewage and industrial wastes. The present study elucidates the impact of physicochemical characteristics of river Cooum on the karyology of a native fish species Mystus vittatus. Fingerlings of M. vittatus were collected from the pond of Inland Fisheries Research Stations and Arumbakkam site of river Cooum. physicochemical parameters of water were analysed and rapid chromosomal preparation on fish tissues was made following the method of Kligerman and Bloom. Seasonal variation on the concentration of heavy metals in the experimental site was mainly due to rain and was remarkable over the control pond. Such incidental variation at Arumbakkam site is attributed to the proximity of a number of industries, whose discharge might have influenced the heavy metals. The control species of M. vittatus obtained from the culture ponds reveals the diploid 2n = 56 chromosomes, while the species from the polluted river cooum shows polyploidy and endoreduplication and condensed nature of chromosomal morphology irrespective of the season. There has been vast differences between the control and experimental fish samples with regard to the percentage of polidy in relation to season, in both the of gill and kidney cells. Obviously pollutants cause irreparable damage to the genetic material of the fish as they are indicators of aquatic pollution.