Benthos abundance pattern and species composition in conditions of pollution in Amursky Bay (the Peter the Great Bay, the Sea of Japan).

Multivariate statistical analysis of data on environmental variables and benthic macrofauna, of 30 sites from four surveys done between 1986 and 1989 in Amursky Bay, is presented. The purpose of this study is to investigate a contamination gradient, assess effects on benthic fauna and evaluate quantitative and qualitative benthic parameters. Contamination was assessed using chemical data from PCA-ordination analysis. Clear patterns were found using three categories, moderate, severe and gross. Significant changes in the number of taxa, density and ecological indices are observed between severe and moderate levels. Changes in these parameters, excluding the number of species, were also detected between gross and moderate levels. Only biomass differs non-significantly. However results of cluster analysis and MDS ordination indicate that two benthic communities exist in Amursky Bay. The most "contaminant insensitive" species polychaetes are Tharyx pacifica, Dorvillea (Schistomeringos) japonica, Dipolydora cardalia, Capitella capitata, phoronid Phoronopsis harmeri. Contaminant sensitive species include Maldane sarsi, Lumbrineris sp. and Scoloplos armiger.