The effects of pollution in the drainage area of a Dutch lowland stream on fish and macro-invertebrates

Summary

Investigations in a Dutch lowland stream, fed by superficial groundwater and polluted by liquid manure from industrial production, show that direct pollution via drain-off can kill the total population of fishes such as Salmo fario and Lampetra planeri. Most running water invertebrates are restricted to stretches with high current velocity, which is also the case with Cottus gobio. Pollution of the groundwater by the same substances leads to a continuous enrichment of the original oligotrophic and acid stream. The result is a shift in distribution patterns and numbers of certain species. Incidental dumping of liquid manure and of beet-pulp afterwards make disappear more species (Cottus gobio, Elmis aenea a. o.) and reduces many others to such a low level that they are threatened by extinction.