Macrobenthic communities of the coastal waters of Dabhol, west coast of India

Abstract

Macrobenthic community of a shallow subtidal (5-20 m) muddy deposit off Dabhol was investigated. Sediment comprised mainly of silt and clay with less of sand. Dominance of clayey-silt fraction reflects on active flocculation of fine grain particles. The sediment organic carbon with a mean value of 1.42% was rather high. The population density of macro-invertebrates varied from 250 to 600 no.m-2 (mean=395 plus or minus 111) during December 1994. The values increased significantly during December 1996 and ranged between 400 and 975 no.m-2 (mean = 621 plus or minus 194). Macrofaunal community comprised of typical near-shore species, numerically dominated by polychaetes. The sediment organic content reflects on the high biological productivity of the area, particularly benthic production that was evident from a good fish catch in the experimental bottom trawling. Values for species diversity followed more or less similar trends and less variability among the sampling stations in Dec. 1994 and Dec. 1996. However, species composition indicated the dominance of different taxa among the sampling locations during two sampling years. The occurrence of juvenile forms of decapods (shrimps and crabs) in the benthic samples suggest that the coastal waters of Dabhol provide favourable environmental conditions for feeding and breeding of commercially important prawn and crab species.