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Introductions and transfers 3.2 Among the most pressing issues to be addressed is the control of introductions of non-native fish and the movement of fish between catchments within Scotland. Although there is legislation in Scotland to control introductions, the powers are less robust than those in England, Wales and Northern Ireland. There is no legislation prohibiting the movement of native fish between catchments, save for the provisions in the 1986 Act in respect of salmon. Section 24 of that Act makes it an offence to introduce salmon or salmon eggs into inland waters in a salmon fishery district for which there is a DSFB without the prior permission of the board, unless the waters are, or are part of, a fish farm. More comprehensive controls are available in England and Wales through section 30 of the Salmon and Freshwater Fisheries Act 1975, which makes it an offence to introduce any fish into inland waters without the permission of the Environment Agency. The provisions in the 1975 Act (as amended by the Environment Act 1995) for screening to prevent the ingress of wild fish to, and egress of farmed fish from, fish farms are also much stricter in England and Wales than in Scotland. |
| Dry river channel |
3.3 Other fish movements can be controlled by the Wildlife and Countryside Act 1981 and the Import of Live Fish (Scotland) Act 1978. The 1981 Act applies only in the case of fish not ordinarily resident in Great Britain and those listed in Part I of Schedule 9 to the Act, and where they are to be released to the wild. This cannot prevent the introduction to Scotland of fish, such as ruffe, which are native to southern Britain but not to Scotland. The 1978 Act applies to fish not native to Scotland, but prohibition of import, keeping or release depends on the making of Orders naming the fish to be excluded. Three such Orders have been made, in respect of Coho salmon, pikeperch and non-native crayfish species. A different approach has been taken in England and Wales, where a compendium Order prohibiting the keeping or release to the wild of more than 20 species was made in 1998.
3.4 The use of regulations to restrict the import, keeping or release of fish has had to be carefully considered because of the implications for free trade. Thus, the regulations have generally focused on the keeping or release of fish rather than their importation.
3.5 The spread of non-native species, whether deliberately or accidentally, can threaten freshwater biodiversity in a number of ways. For example, the introduction of six new non-native species of fish to Loch Lomond since 1980 could disrupt the fish community there in various ways. One of the introduced species, the ruffe, feeds on powan eggs. This may have unforeseen effects both on the powan population, and on an internationally important river lamprey population, which feeds as a parasite on powan and other fish in the loch.
3.6 The introduction of regulations can be only part of the attempt to address this problem. Their value comes into force largely only after fish have been moved. Experience with the introduction of ruffe, mink and North American signal crayfish shows that, once it has become established, a non-native species may be very difficult to eradicate. Whilst stronger legal safeguards may well be necessary, these are unlikely to be effective unless they are also accompanied by better information about the value of Scotland's native freshwater fish, and a shared commitment to their protection. There is an urgent need for action to inform the public about the implications of moving fish between different parts of the country. Clearly the lead on this issue should be taken by SERAD and SNH, but there is a role for bodies such as the Scottish Anglers National Association (SANA), the Salmon and Trout Association, the Scottish Federation for Coarse Anglers, the Pike Angling Club of Great Britain and Ireland, angling clubs and associations, and the angling press, to ensure that the message is disseminated - and understood - as widely as possible.
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3.7 The North American signal crayfish was introduced into the River Dee in Kirkcudbrightshire some years ago, and was discovered recently in the Rivers Clyde and Earn. There are fears that in the wild, this aggressive species will disrupt freshwater ecosystems through predation and habitat damage. As a result, its release to the wild is illegal. 3.8 The introduction of other non-native animals, such as mink, and the possible reintroduction of animals that were native to the country but which have become extinct, such as the European beaver, have raised concerns about the impacts they may have on fish. Mink are known to prey on fish and concern has been expressed recently about their spread not only in mainland Scotland but in the islands. Although beavers do not eat fish, concerns have been raised that their dam-building and burrowing activities, and their effects on riparian woodland may have impacts, particularly on salmonids. On the other hand, the presence of beavers may be beneficial to other freshwater fish species which tolerate higher temperatures and higher nutrient loads. In considering whether the beaver should be reintroduced to Scotland, SNH has followed the guidelines for reintroductions published by the International Union for the Conservation of Nature. These guidelines are intended to "... help ensure that reintroductions achieve their intended conservation benefit, and do not cause adverse side effects of greater impact". |
| North American signal crayfish |
Predators
3.9 A number of fish, birds and mammals prey on fish. For example, juvenile salmon may be eaten by a number of different predators including eels, perch, pike, trout, kingfishers, dippers, sawbill ducks, herons, gulls, terns, otters and mink. Much of this predation will have little or no effect, especially where it involves very young, small fish, because the fish populations may be able to compensate for the losses as a result of increased growth and survival of those that remain. This compensatory mechanism is known as 'density-dependence'. However, when fish reach the larger parr and smolt stages, they lose the ability to compensate for losses to predation. Predator species may also be protected on SSSIs and by the species protection provisions of the 1981 Act. They may also be afforded protection where sites are intended for designation under two EU Directives, the Habitats Directive (see above) and the Birds Directive, which contains similar provisions but for certain bird species. To an extent, the well-being of these predatory species depends on that of their prey, as part of the natural function of food webs. However, there is a concern that predation may have an adverse effect on fish populations, and any associated fisheries.
3.10 On their return migration, salmon may be injured or eaten by, for example, cetaceans, seals and otters. Except during the close seasons defined in the Conservation of Seals Act 1970, seals may be shot providing the appropriate firearm and ammunition is used, and licences to shoot seals during the close seasons may be issued by SERAD if serious damage is being caused to fish or fishing gear.
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Aquaculture 3.12 Aquaculture in Scotland includes not only salmon farming in sea lochs and smolt rearing in some freshwater lochs, but also farm production of brown trout and rainbow trout for table and fishery purposes. Many of the problems that may be associated with aquaculture are common both to freshwater and marine operations. Concerns have been expressed over the possible impacts on wild stocks of escaped farmed fish, and of disease and parasite transfers. |
| Female goosander |
3.13 To address these concerns, particularly in relation to sea trout in the north west and west of Scotland, a Tripartite Working Group comprising representatives of the fish farming industry, the wild salmon interests and SERAD has been established. This Group is identifying measures for enhancing or, where necessary, restoring stocks, and areas where such initiatives may be implemented and monitored. Area Management Agreements are being drawn up by representatives of wild fish and fish farming interests for a number of west coast catchments. These agreements will involve developing integrated treatment of sea lice and fallowing regimes on fish farms in a given area and close liaison between fish farmers and the wild fish interests.
3.14 In 1994, NASCO adopted the Oslo Resolution, which calls upon signatories to the NASCO Convention to implement measures to reduce the impact of fish farming on wild salmon stocks. It calls for the introduction of measures to reduce the numbers of fish that escape from fish farms and the development of site-specific contingency plans to deal with escapes. A working group, comprising representatives of the fish farming industry, the Association of Salmon Fishery Boards (ASFB) and SERAD has been established to tackle these issues, including the adequacy of current reporting systems, which is not presently addressed in legislation.
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3.15 SERAD recently issued guidance to planning authorities on marine fish farm developments. Amongst other things, this mentions concerns about the effects of salmon farming on migratory salmonids and on associated freshwater pearl mussel populations. The production of similar guidance is being considered in relation to freshwater farms. It is expected that 'fish farm framework plans' and Local Biodiversity Action Plans will guide the future development of marine salmon farming and take full account of potential effects on freshwater biodiversity. |
| Marine salmon farm © Lorne Gill/SNH |
3.16 A Joint Working Group comprising representatives from the fish farming industry and SERAD was established following the outbreak of Infectious Salmon Anaemia, 'ISA', in 1998. The Group's remit was to investigate the outbreak and spread of the disease and to suggest ways in which farming practices could be adjusted to minimise its impact and that of any other disease that may arise. The report of this group has just been published.
Wider environmental influences
3.17 Many other environmental factors also affect freshwater habitats and the fish that live in them. These may include changes in the Earth's climate as a result of global warming, which may affect rivers and lochs, through altering water temperature, rainfall and snow patterns, and flow regimes. Diffuse pollution from agriculture, forestry and industry may cause problems in some areas, and acidification resulting from atmospheric pollution has led to the extinction of fish populations. Other factors that can affect fresh waters and the fish they support include abstraction, point source discharges, and construction or other engineering works.
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3.18 These areas were considered in detail by the SSSTF. Whilst the Task Force's report focused on threats to salmon and sea trout, most of the associated environmental quality issues apply equally to other freshwater fish. The points below summarise relevant progress made since the publication of that report in 1997.
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| Water sampling |
3.19 The proposed EU Water Framework Directive offers an opportunity to take a step forward in the way that such environmental problems affecting Scotland's rivers, lochs and coastal waters are tackled. It sets the framework for an holistic approach to planning the protection and improvement of water resources based on natural river basins. The Directive will update and replace some of the older Community water legislation (including the Fresh Water for Fish Directive) and provide a framework for the operation of others, such as the Nitrates and Urban Waste Water Treatment Directives. Management plans must be drawn up with co-ordinated programmes of measures designed to ensure good status of both surface and ground waters within a specified timetable. Stakeholders must be involved in the whole process, with comprehensive consultation. The Directive is expected to be agreed in its final form towards the end of this year. The Scottish Executive and SEPA are taking forward planning for its implementation in Scotland.
The viability of fish populations may be affected directly by factors such as competition from and predation by introduced species of fish and other animals. Such factors cannot be controlled simply by the introduction of new legislation. Fishery managers and anglers have roles to play in controlling the introduction of species that should not be here. Other factors that may act directly on fish include predation by native fish, birds and mammals, and the impacts of aquaculture. Predators themselves may be protected, and this may become a particular problem where both predator and prey are protected at the same place. Fish may also be affected indirectly, however, by impacts upon the environment in which they live as a result of, for example, the effects of agriculture, forestry, pollution, abstraction and in-river engineering. A number of codes of practice have been and are being developed to address these problems. The proposed EU Water Framework Directive will require a more holistic approach to the management of these activities and the protection of the freshwater environment.
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