Patterns of drift and power station entrainment of 0+ fish in the River Trent, England

Entrainment of 0+ riverine fish (mostly pelagic cyprinids) by a power station intake, and down‐river drift over a nearby weir, followed the same pattern, occurring throughout the year and being greatest during the night in the first weeks of life (i.e. in summer), reaching a peak shortly after dusk. Entrainment and drift of benthic species, and of fish older than 0+, were negligible. Mortality following entrainment was 100%. Impingement of fish on the intake screens was negligible, probably because individuals larger than the screen mesh were able to escape the intake current. The species composition and length‐frequencies of the drifting fish, but not their overall abundance, showed some variation with distance from the river margin. It is argued that the fish vulnerable to entrainment are those 0+ individuals which are dispersing in the river by drifting.