Response of the fish populations of the River Don in South Yorkshire to water quality and habitat improvements

The River Don in Yorkshire, UK, has suffered a legacy of pollution and land contamination that dates back to the Industrial Revolution. The river cont inues to be impacted by discharges from industry, mining and sewage sources , resulting in poor water quality and considerable damage to the fish stock s. Some modest reductions in ammonia, biochemical oxygen demand (BOD) and m etal levels have been achieved through improvements to sewage treatment wor ks and the shutting down of some industries. The decline in the steel indus try has generally led to sustained low and acceptable levels of iron and ni ckel in the river; although some locations are impacted by ochre from aband oned mines. As a consequence, recreational fishing in the catchment remains restricted at many locations. Fish stocking and enhancement programmes hav e so far been ineffective due to setbacks from ad hoc pollution incidents a nd degraded habitats. It is suggested that the water quality and habitat de gradation problems be addressed prior to embarking on any large-scale fish stock enhancement programmes. This would require substantial financial inve stment and it is recommended that funding be actively sought from both inte rnal and external agencies to achieve this objective. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.