LONG-TERM STUDIES OF THE BENTHIC BIOLOGY OF TEES BAY AND THE TEES ESTUARY

Tees bay on the north-east coast of England receives the waters from the highly industrialised Tees estuary. Since 1970 there have been considerable reductions in both the industrial and domestic sewage discharges to the estuary. The benthic populations of Tees bay have been routinely monitored since 1971, grabbing surveys have been completed at six areas in the spring, summer and autumn of each year. In 1979 the survey was extended to include stations within the Tees estuary itself. Tees bay appears to have a stable benthic fauna. Though the simple analysis of faunal statistics has demonstrated fluctuations within the benthos, neither this analysis nor classification analysis has indicated that there were any long-term changes in abundance or diversity. Classification analysis has also failed to differentiate between the fauna of the different areas within Tees bay. However, studies of biomass and T. fabula growth rate did indicate a difference between the areas close to the mouth of the Tees and those remote from it. The studies of the Tees estuary benthos indicated an improvement in both the abundance and the diversity of the fauna. However, the monitoring took place over a limited period and further work is necessary to ensure that this improvement does not simply represent natural fluctuations within the estuarine benthic population. © 1990 Kluwer Academic Publishers.