The distribution of O+ perch, Percafluviatilis L., in a lacustrine environment is described.Since the perch occupied many different habitats within the ecosystem throughout their first year of life a number of sampling techniques were required to sample the population. The early larvae and post larvae were planktonic and their distribution could be related to the effect of the of the winds. As soon as the young perch developed fins an inshore migration began. Virtually all the fish had completed this migration by the time they reached a total length of 19 mm but the majority of the population reached the shoreline before attaining this size. During June and August the O+ perch formed large shoals around the shoreline especially in sheltered areas in water less than 3 m deep. At the end of August probably in response to falling lake temperatures the perch fry migrated into deeper water.

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This paper describes specimens of naturally occurring hybrids of silver bream x bronze bream and silver bream x roach from Lincolnshire and South Humberside waters.

The operation of a put‐and‐take trout fishery at Toft Newton reservoir is analysed from detailed studies of the 1978 and 1979 seasons. Toft Newton is only a small reservoir but the large number of anglers that utilize the fishery mean that the stocking rates per hectare of water have to be very high. As a result of these high densities and a short average residence time in the reservoir, rainbow trout which were the predominantly stocked species do not grow after release. Brown trout, however, which were stocked at lower densities do grow after release. The success rate of the 8–9% of anglers not returning their catch data was examined using a postal survey. Partial correlation analysis indicated that the numbers of fish in the reservoir, the number of anglers fishing and the number of hours of sunshine significantly affected the catch rate. A regression between catch rate and number of fish in the reservoir only explained 35% of the variability but the addition of the other two factors did not significantly improve the accuracy of the model. The market area of the fishery was studied from the register of anglers. Most anglers attending Toft Newton travel a considerable distance to the fishery, the peak number driving from 98–129 km (61–80 miles) round trip. The present and future management policy of the fishery is discussed in the light of this analysis and many of the recommendations may also apply to other small put‐and‐take trout fisheries.