Fish mortality by impingement on the cooling-water intake screens of Britain’s largest direct-cooled power station

An estimated 5.66 × 107 fish (summed quarterly 95% confidence intervals: 3.01 × 107–1.07 × 108) weighing 258.4 t (143.2–467.9 t) were killed on the cooling-water intake screens of the 2400 MW Longannet Power Station (Forth estuary) in January 1999–December 2000. Abundance and number of species (40) collected were close to predictions for a power station of this size and latitude. Potential losses of equivalent adult whiting (Merlangius merlangus), cod (Gadus morhua), and plaice (Pleuronectes platessa) through deaths of juveniles were estimated at 353.1 t (208.0–603.2 t) worth approximately €429,266 (€246,592–752,765) in 1999–2000. Fish catch-per-trawl in the estuary was generally not noticeably greater during a year of low water withdrawal (coal miners’ strike of 1984–1985) when compared to other years from 1982 to 2001, except for gobies (Pomatoschistus spp.). A fish-return system is being tested at Longannet to reduce mortality.