Don Fishery Management Plan - RAFTS

3.4 PREDATORS AND COMPETING SPECIESFish-predating species on the Don include mammals, birds and fish. Common seals,Phoca vitulina, are known to use the Don estuary as a haul-out, also taking some largesalmonids, but fewer than the rods (Carter et al., 2001). Individual seals have been culledby the coastal netsmen when they have been a problem. Cormorants, Phalacrocoraxcarbo, are present on the lower river from the autumn through to the late spring.Predation by coarse fish species, such as pike and perch, has not been quantified andmore information is required on their numbers to determine if they are sufficientlyestablished as to have a localised impact.The presence of the American mink (Mustela vison), the Goosander (Mergus mergansera saw-billed duck), and the Grey Heron (Ardea cinerea) is more widespread through thecatchment and so all areas are likely to be predated. Although their impact on thejuvenile population has not been quantified, all typically predate on parr-sized fish andsalmonid species are likely to be most affected as they are the most numerous. Predatorcontrol is not carried out by the Don DSFB although individual proprietors may carry outsome mink trapping.15