CONTINUED OBSERVATIONS OF THE BENTHIC FAUNA OF THE INDUSTRIALIZED TEES ESTUARY, 1979-1990

The Tees Estuary is a heavily industrialised estuary in the North-East of England. Since the early 1970s water quality in the estuary has gr adually improved, and in order to assess the impact of that improvemen t on the estuarine benthos a quantitative survey was established in 19 79 and repeated annually. The results of the surveys have been analyse d using both univariate and multivariate statistical techniques and re lated to local meterological data. During the monitoring period there was an increase in diversity at the seaward end of the estuary and the area of the estuary defined by classification analysis as the ''Marin e Zone'' extended further up the estuary. All of the analyses identifi ed an impacted area close to the mouth of Dabholm Gut; an intensive lo cal sampling regime in this area delineated the impacted area and indi cated limited improvement during the course of the study period. The r esults of the monitoring exercise indicate that improvements in water quality have led to an improvement in the benthic biology of the estua ry.