Don Fishery Management Plan - RAFTS

Improvement Association collates information on the number of fishing permits sold, butassessing the quantity of fish and their sizes would provide useful information for themanagement of the brown trout fishery and monitoring its performance.A scale sampling programme will allow information to be gathered on growth rates infreshwater, smolt ages and sizes, confirm whether salmon are grilse or multi-sea winterfish, i.e. how long they have spent at sea, the age at maturity for brown and sea trout andthe incidence of repeat spawning.Survey MethodAs a minimum, the Don DSFB can ask to receive a monthly breakdown of all the catcheswhich have been submitted to the Scottish Government since 1952, which would providesome indication of how the timing of salmon and sea trout runs for the river as a wholehas changed over that period.To allow different parts of the river to be compared permission will need to be soughtfrom proprietors and angling clubs from a number of representative fisheries on the riverto access their fishing records. From these sources the numbers of fish of each speciescaught and their weights can be examined by month for each year and changing trendsnoted for the whole river and for sub-catchments. It is unlikely that changes in thefishing effort can be fully quantified.If possible the records of the coastal netting stations should be examined for changes inthe time of year salmon and sea trout are entering the river.Brown trout catch records are likely to be less detailed, particularly as many permits aresold as day tickets and casual anglers may be less inclined to report back at the end of aday’s fishing. Following on from the work of Shields (1996), examining the catchrecords will determine if the numbers of brown trout being caught are continuing todecline, whilst the weight of individual fish is increasing through reduced competition forresources. Reporting through the River Don Brown Trout Improvement Association as acentral body should be encouraged to improve the understanding of the brown troutfishery and improve its management.Scale sample packets and instructions should be distributed through the fisheries so thatsalmon, sea trout and brown trout samples can be collected. RDT staff should be trainedin reading the scales to determine ages and growth rates as mentioned above. FisheriesResearch Services can provide such training.28