BEAULY SYSTEM FISH AND FISHERY ACTION PLAN ... - RAFTS

IV. Barriers to Migration.Poorly designed road culverts, bridge aprons etc have reduced the availablehabitat for many fish species, particularly those adopting an anadromous lifehistory. Some obstructions / potential obstructions have already been identified inhabitat surveys. Log jams can cause similar problems and can be regarded asepisodic in nature. Habitat surveys will continue in order to identify log jams,culverts etc.V. Cultural Oligotrophication.Evidence from sediment cores in Loch Ness suggests that the nutrient status of thehigher reaches of the Ness catchment has altered considerably since the last iceage due to both natural and anthropogenic factors. It is likely that the naturalproductivity of many upland areas in the Beauly catchment has been lowered as aresult of a similar process.VI. Exploitation by Fisheries.Despite the adoption of catch and release within the Beauly catchment it is likelythat some salmon and sea trout populations which are currently numericallydepressed are over-exploited by fisheries leading to a reduction in the number ofadults available for spawning.VII. Forestry.Large areas of the Beauly catchment contain commercial forestry plantations.Forestry practices may have both positive and negative impacts on fishproduction. Negative impacts are likely to include silt inputs, acidification andover-shading of watercourses. Positive impacts include the provision of shade.Habitat surveys are currently being undertaken to assess the extent of forestry thatdoes not conform to the published Forest and Water Guidelines.VIII. Climate Change.An emerging and episodic influence on fish production is the apparent increase insevere weather conditions, particularly flood episodes. There is an increasedprobability of redd washout etc as a result of this factor. Linked to this areincreased proposals for hard engineering, gravel removal etc in respect of flooddefence schemes all of which have the potential for damaging fish stocks.IX. Pollution.Diffuse and point-source pollution occurs in various locations within thecatchment although overall water quality appears to be good. A particular concernhas been perceived high levels of pollution in the Moray Firth.27