Distribution of Chaetognaths in the Polluted and Unpolluted Waters around Bombay

Abstract

Chaetognath fauna inhabiting the nearshore waters of Bombay was studied during Oct. 1977- Sept.1978. Among the 4 stations investigated Thana and Mahim represent polluted regions while Harbour and Versova are relatively unpolluted.Maximum density of chaetognaths at all stations was obtained during postmonsoon period. Fluctuation in the population of chaetognaths was greater in the polluted than in the unpolluted water. Sagitta bedoti was the most common species in the collections. Juveniles of S. bedoti were in appreciable numbers throughout the period of collection. Breeding of S. bedoti was continuous in the nearshore waters with a few intense spawning periods. The other species present were S.bombayensis,S. enflata, S, oceania,S. pulchra and S. robusta. Species diversity was more in the unpolluted waters. It would appear that the disappearance of sensitive species and the consequent decrease in diversity may be the first indication of impending deterioration of the environment