I thank the committee for inviting Scot Mathieson and me to talk to you today. This will be a joint opening statement on behalf of SNH and SEPA.
Invasive non-native species—or INNS, as I will refer to them from now on—are considered to be the second most important reason for biodiversity loss globally, after habitat loss and fragmentation. They are extremely damaging to our environment, economy and health and cost Scotland as much as £250 million annually.
Crayfish are highly invasive. As you have heard, they have been introduced to a number of bodies of water. Where they have been introduced, they have the potential to have adverse impacts on the aquatic ecology of many of our freshwater habitats.
To put this in context, the Convention on Biological Diversity placed an emphasis on INNS prevention measures, on the basis that that is better than the cure. Once INNS become established, their control or eradication can be technically challenging. It can be very expensive and, in some cases, it is not even possible. Prevention is the least environmentally damaging option. With adequate resources, it can be applied to a greater or lesser extent across the whole spectrum of invasive species threats. That principle is repeated and given the greatest priority in the Convention on Biological Diversity’s Aichi targets, the European Union biodiversity strategy and the 2020 challenge for Scotland’s biodiversity.
EU regulation 1143/2014, on INNS, introduces a statutory requirement on member states to ban the keeping, transportation and sale of species of EU concern. Signal crayfish are a species that is being considered for listing in that regard, with priority being given to species that have yet to arrive and those that are at an early stage of their invasion.
The habitats directive and the water framework directive also require action to prevent the deterioration of vulnerable habitats and species. Scotland is renowned for the quality of its rivers and has international responsibility for its freshwater pearl mussel, lamprey and Atlantic salmon. The spread of signal crayfish has the potential to have adverse impacts on those interests, and that could affect our ability to meet the requirements of those directives.
The top priority with regard to signal crayfish is to prevent their spread to other catchments. The distribution of signal crayfish is quite limited. In 2010, it was estimated that 174km of river length was infested with signal crayfish; that is 0.1 per cent of the river length in Scotland. They are, of course, present in some of our lochs and ponds, Loch Ken being the reason that we are here today. Signal crayfish are, in most instances, unable to move between catchments. They are not great movers in their own right. They tend not to move between catchments without the help of humans and it is vital to prevent a deliberate or accidental movement between catchments.
SNH and Marine Scotland have considered several applications in the past for licences to trap signal crayfish in Loch Ken. SNH as the licensing authority assesses all licence applications objectively. We have to weigh the benefits of trapping against the risk of encouraging further spread. If we allow a commercial crayfish fishery to develop in Scotland, there is a high risk of encouraging the deliberate introduction of crayfish to other catchments. That is supported by evidence from elsewhere, where giving a commercial value to non-native crayfish has resulted in further introductions to previously uninvaded areas in a number of countries. Studies in Sweden and Spain have demonstrated that the establishment of crayfish fisheries has led to their increased dispersal to new areas, often to develop a new fishery in other waters.
The policy position of the Great Britain non-native species programme board, of which the Scottish Government is a member, is that there should be a presumption against the commercial exploitation of invasive non-native species. The only circumstances in which regulatory authorities should permit their commercial exploitation are where INNS are widely established and commercial exploitation is unlikely to jeopardise the potential for future management prospects. In other words, it should not make the situation worse. Any proposal that creates a market incentive for people to introduce signal crayfish elsewhere in Scotland has the potential to make the situation worse.
Trapping is regularly proposed as a solution to the crayfish problem, most often by individuals who wish to exploit populations in Loch Ken or elsewhere in Scotland, either for personal consumption or for sale. It is widely accepted, however, that trapping does not remove all life stages of crayfish and is not effective as a method of eradication. Although high-intensity trapping may reduce the numbers of large crayfish—particularly male crayfish—in some areas, the resulting compensatory growth in production of wild crayfish can mean that the benefits are lost.
Where trapping is licensed in the United Kingdom, both the Environment Agency and the Centre for Environment, Fisheries and Aquaculture Science admit that there are weaknesses in their licensing systems. The blanket ban on keeping live crayfish in Scotland is clearer and more enforceable than the postcode map of go and no-go areas in England, which allows live crayfish to be shipped into no-go areas for the catering trade. That situation led to the tabling in 2013 of cross-party early day motion 659, which called on the Government
“to give urgent consideration to emulating Scottish biosecurity control measures in England and Wales, to review the 2004 Crayfish Byelaws and to ban the live transport and sale of all alien crayfish species in England and Wales.”
Prevention is a top priority in tackling the spread of signal crayfish between river catchments. The check, clean, dry campaign is a GB-wide biosecurity campaign to raise the awareness of water sports enthusiasts about the risks of non-native species introductions. Those three simple hygiene steps have been shown to significantly reduce the risk of spreading invasive plants and animals between catchments on damp equipment.
SEPA has been working with a range of national water sports and fishing groups to promote the check, clean, dry campaign across Scotland. Since 2012, more than 380 fixed signs have been installed at key locations. More than 8,000 leaflets and posters have been distributed and many partners now feature check, clean, dry on their websites and include biosecurity in their training programmes.
SEPA has also just produced a biosecurity pack for event organisers, which is endorsed by a range of water sports users. Both SNH and SEPA recognise the impact that the negative press about crayfish in Loch Ken has had on businesses that rely on visiting anglers. This year, we will begin a survey of angling catches with a view to assessing the future viability of that fishery in Loch Ken. One of the project’s aims will be to promote the opportunities that the area has to offer visiting anglers.
Together with the Forestry Commission, Dumfries and Galloway Council, SNH and SEPA are promoting alternative green tourism activities in the area. Dumfries and Galloway Council has gathered ideas for ways to promote the landscape and the natural heritage of the River Dee catchment and is due to submit a funding bid to the Heritage Lottery Fund this week.
Nature-based tourism is worth £1.4 billion a year to Scotland’s economy and it supports 39,000 full-time equivalent jobs. Field sports, including angling, contribute around a tenth of that total, or £136 million per annum. Local initiatives such as the Galloway kite trail, 7stanes and dark skies are already attracting new visitors to the area.
As a licensing authority, SNH is open to discussing any proposals for the control of signal crayfish in Loch Ken. However, they must address the risks of encouraging their spread elsewhere. The top priority is to manage the threat and prevent the spread of signal crayfish in Scotland.