THE FISH OF THE RIVER STOUR, SUFFOLK C . R . K E N N E D Y , R . BURROUGH, C . AVES AND J. LANDSBERG
Introduction THE River Stour, like many East Anglian rivers, is extensively managed for purposes of water supplies. Its flow to the sea is contained by a barrage scheme, water is abstracted from it along its length, and it receives water from the R. Ouse as part of the Ouse-Essex water transfer scheme. This management is bound to have some effects upon the fish of the river, and so in August, 1974, an intensive survey of the fish was carried out on the reach between Fiatford Mill and Cattawade. The survey was supported by the Suffolk Naturalists' Society, and was undertaken by the authors with the assistance of the Essex River Division of the Anglian Water Authority. Its particular aim was to investigate the distribution, growth, feeding and parasites of the fish present, with a view to providing base line data against which to measure any further changes in the fish due to water management, and to providing information on the fisheries for anglers and for courses held at Fiatford Mill Field Centre. The results of this survey are presented in the present paper. Sites and Methods Fishing was only carried out on the R. Stour between Fiatford Mill and Cattawade on the Northern branch of the river, and on the lowest reaches of the Southern branch (O.S. Map inches to 1 mile No. C6503). Fishing Operations were carried out by the bailiffs of the Anglian Water Authority using an A.C. electric fishing machine mounted on a boat, and supplemented by seine netting where necessary. The river was fished in stretches as follows: the Mill Pool below Fiatford Mill, Judas Gap, Judas Gap to Cattawade, Cattawade Pool, and the Stretch on the Southern branch referred to as Dedham Old Cut. All the fish caught in each Stretch were identified and their fork length recorded. The majority were then returned to the river, but samples of each species were retained for further examination. These were aged, using scales or opercula as appropriate, their stomach Contents were recorded and they were examined for the presence of parasites. All parasites found were identified, and their numbers and positions recorded. Distribution of fish The numbers of fish and the sites at which they were caught are shown in T A B L E 1 . In general the species found are those that