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Title: Fisheries survey 1990 : River Coln, River Churn, Ampney Brook : key site monitoring in relation to low flow problems
Document Type: Monograph
Nine key sites were surveyed in October and November of 1990 in order to monitor any changes from the 1989 survey with particular respect to low flow problems. The four sites on the River Churn and three sites on the River Coin were sampled by electrofishing. The two sites on the Ampney Brook were surveyed by visual inspection as the watercourse was entirely dry during the survey period. The River Coin survey concluded that no significant changes had occurred with one site having remained reasonable, one site having remained poor and one site having remained good. Flow regime is a key factor in determining fishery quality particularly via indirect effect on habitat factors such as siltation of spawning gravels and loss of desirable instream vegetation. No effective recruitment of brown trout was found at any of the key sites. The River Churn survey concluded that two sites had shown significant deterioration, one remaining poor and one remaining satisfactory. The drying up of the section between Siddington and downstream of the Spine Road Bridge represents a clear case of low flows causing severe direct damage to a significant fishery. No effective recruitment of brown trout was found at any of the key sites. The Ampney Brook survey concluded that the fish population had been eradicated due to it drying up for the second consecutive year. Recommendations include continued annual monitoring of fish populations at the key sites together with relevant environmental and other factors. An investigation into the hydrology of the three watercourses concerned with particular respect to groundwater abstraction should be undertaken. A confirmed significant impact would require a further investigation of the options for alleviation of low flows. Habitat enhancement opportunities are extensive and it is this area that the Authority should target and develop in order to produce sustainable benefits to the fish population.
Publisher: National Rivers Authority
Publication Date: 1990
Publication Place: Reading
Subject Keywords: FishesPopulation dynamicsSpecies distributionFlow rateRiversHabitat improvementNature conservationFisheries
Geographic Keywords: Coln (Gloucestershire)Cotswolds catchmentCotswolds
Extent: 94
Total file downloads: 45

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