In 2009, the Clyde River Foundation produced the River Clyde Fishery Management Plan (RCF), within which was a core action to construct a biosecurity plan for the area. It presents actions agreed with stakeholders for the prevention, early detection, control and mitigation of the introduction and spread of selected invasive non native species (INNS), fish diseases and parasites. The vision of this plan is:
‘To develop a sustainable framework to prevent, detect, control and eradicate invasive non-native species within the RCFMP area through the coordination of data collection, management, liaison, and education.”
The nature of the problem
Biosecurity issues are of increasing economic and ecological significance. Globalisation has expanded the extent and complexity of world trade, and increasing tourism has expanded the number of destinations for activity holidays and travellers. These trends have led to the increased probability of unintentional and intentional introductions as well as the establishment and spread of invasive non-native species (INNS), parasites and diseases in Scotland and the UK. This plan considers biosecurity issues in the rivers, canals and lochs of Scotland in relation to the potential introduction and spread of a priority list of INNS and fish diseases.
Many non-native species exist in our ecosystems without having any adverse effects on the environment. INNS however, have a negative impact on biodiversity by displacing or preying upon native species, by destroying habitats or by introducing new diseases or parasites. INNS are, after habitat loss, the second greatest threat to biodiversity, being capable of rapidly colonising a wide range of habitats and excluding native flora and fauna (CBD 2006) . Over the last 400 years, INNS have contributed to 40% of animal extinctions with attributable causes. As water is an excellent transport medium for the dispersal of many of these species, rivers, canals, lochs and their banks and shorelines are amongst the most vulnerable areas to the introduction, spread and impact of these species. The ecological changes wrought by INNS can further threaten already endangered native species and reduce the natural productivity and amenity value of riverbanks, shorelines and of the water bodies themselves.
A survey commissioned by SNH in 2000, identified approximately 1000 non-native species in Scotland. The threat from INNS is growing at an increasing rate assisted by climate change, pollution and habitat disturbance, with correspondingly greater socio-economic, health and ecological costs. Scotland is now facing complex and costly problems associated with INNS, for example:
- DEFRA has estimated that INNS cost the UK economy £2 billion per year.
- In the UK, Japanese Knotweed is thought to affect an area roughly the size of London and the Review of Non-Native Species Policy (2003) estimated the total cost of its removal using current techniques at £1.56bn.
- A Scottish Government report estimated the potential Net Economic Value loss to Scotland of the introduction of Gyrodactylus salaris (a parasite of Atlantic salmon) at £633 million, with severe consequences for rural communities.
- A Forestry Research report estimated the current cost of clearing invasive Rhododendron ponticum from Argyll and Bute as £9.3m, which could rise to £64m in the next 50 years.
INNS have already changed the character of iconic landscapes and water bodies in Scotland, reducing their amenity value. There is also a growing recognition of the impacts of translocated species. Translocated species are native species which have been transported outside their natural range, and they can also have severe ecological impacts. Examples of translocated species that are impacting the ecology of Scotland’s rivers and lochs are the bullhead (Cottus gobio), minnow (Phoxinus phoxinus) and ruffe (Gymnocephalus cernuus). The ruffe in particular has negatively affected the rare and protected powan (Coregonus lavaretus) in Loch Lomond. It is also important to mention that cross catchment transfer of salmonids has occurred over a number of years which has the potential of leading to the loss of genetic diversity.
Without a coordinated and systematic approach to the prevention of introduction and control of the spread of INNS and fish diseases, it is likely that the ecological, social and economic impacts and the costs for mitigation, control and eradication of these species and diseases will continue to increase. This plan is the first step to set out and implement such an approach at a local level for selected species and diseases that significantly impact freshwater fisheries and the aquatic environment. This local plan and its implementation is also part of a strategic and coordinated approach to INNS management being undertaken across Scotland by RAFTS members.