Preventative measures: The use of potentially invasive alien species for aquaculture and their accidental release/or escape can have negative impacts on native biodiversity and ecosystems. Hewitt et al, (2006) Alien Species in Aquaculture: Considerations for responsible use aims to first provide decision makers and managers with information on the existing international and regional regulations that address the use of alien species in aquaculture, either directly or indirectly; and three examples of national responses to this issue (Australia, New Zealand and Chile). The publication also provides recommendations for a ‘simple’ set of guidelines and principles for developing countries that can be applied at a regional or domestic level for the responsible management of Alien Species use in aquaculture development. These guidelines focus primarily on marine systems, however may equally be applied to freshwater.
Copp et al, (2005) Risk identification and assessment of non-native freshwater fishes presents a conceptual risk assessment approach for freshwater fish species that addresses the first two elements (hazard identification, hazard assessment) of the UK environmental risk strategy. The paper presents a few worked examples of assessments on species to facilitate discussion. The electronic Decision-support tools- Invasive-species identification tool kits that includes a freshwater and marine fish invasives scoring kit are made available on the Cefas (Centre for Environment, Fisheries & Aquaculture Science) page for free download (subject to Crown Copyright (2007-2008)).
The impacts of farmed Salmo salar may be prevented by a number of strategies and technologies. Care should be taken in choosing farm sites as to prevent or reduce the spread of infections diseases and parasites suchs as sea lice (Lepeophtheirus salmonis) to wild fish populations (Thorstad et al, 2006; Amundrud & Murray, 2009).
Sterilization of farm stocks by high pressure induction of triploidy in newly fertilized eggs would reduce the effects of hybridization of escaped S. salar with wild populations and other fishes. It may also reduce the competive effects of these escapees as well. This practice may reduce their survival and growth rate, increase the likelihood of deformities and susceptibility to disease, and induce negative market reactions. Culture of triploid S. salar was attmpted and abandoned in Fundy, Canada due to high susceptibility to the infectious salmon anemia virus. However, promising studies on this method continue (Thorstad et al, 2006).
Domestication of S. salar to the point that individuals can no longer breed or even survive in nature is another possible means of negating possible impacts of farmed stocks on wild populations. It would be a complicated and long term process to do so without comprimising characteristics necessary for a quality yeild (Thorstad et al, 2006).
Physical: The establishment of protected zones that prohibit the cultivation of S. salar is a means of retaining unaffected wild populations of Atalntic salmon. Norway, the top cultivator of S. salar, maintains 29 national salmon fjords and 52 national salmon rivers where new Atlantic salmon farming is prohibited. This protects 75% of wild salmon within the country. Large zones without existing salmon farms exhibited the inteded effect, but existing farms were allowed to remain. Establishing these zones before salmon farms are begun is essential to the effectiveness of this method. Recapture of escaped farmed salmon has been deemed ineffective (Thorstad et al, 2006).
Location Specific Management Information
Salmo salar fisheries must employ a containment management system to prevent the escape offish. Starting in May 2004, all Atlantic salmon placed in net pens must be of North American origin. The use of transgenic fish is prohibited (Naylor et al, 2005).
A study to investigate the spread of sea lice (Lepeophtheirus salmonis) from farmed Salmo salar to wild fish populations has yeilded a three-dimensional numerical model that has been developed and recently validated within Loch Torridon, a fjordic sea loch on the west coast of Scotland. Output from the numerical model is used to drive a particle tracking model which follows statistical representations of sea lice through the planktonic stages of a louse life cycle. By including maturation and mortality, the models can be used to predict the dispersion and transport of infectious sea lice from a point source and can be used to produce maps of infectivity under varying environmental conditions. Results highlight the importance of the wind-driven circulation for larval lice transport and suggest that local environmental conditions have considerable impact on the probability of sea lice infection spreading between wild and farmed fish populations (Amundrud & Murray, 2009).
1. Alaskan Department of Fish and Game. 2002. Atlantic Salmon: A White Paper - March 5, 2002.
2. Amundrud, T. L.; Murray, A. G., 2009. Modelling sea lice dispersion under varying environmental forcing in a Scottish sea loch. Journal of Fish Diseases. 32(1). JAN 2009. 27-44.
3. Cadwallader, P. L. 1996. Overview of the impacts of introduced salmonids on Australian native fauna. Australian Nature Conservation Agency.
4. Centre for Environment, Fisheries & Aquaculture Science (CEFAS)., 2008. Decision support tools-Identifying potentially invasive non-native marine and freshwater species: fish, invertebrates, amphibians.
Summary: The electronic tool kits made available on the Cefas page for free download are Crown Copyright (2007-2008). As such, these are freeware and may be freely distributed provided this notice is retained. No warranty, expressed or implied, is made and users should satisfy themselves as to the applicability of the results in any given circumstance. Toolkits available include 1) FISK- Freshwater Fish Invasiveness Scoring Kit (English and Spanish language version); 2) MFISK- Marine Fish Invasiveness Scoring Kit; 3) MI-ISK- Marine invertebrate Invasiveness Scoring Kit; 4) FI-ISK- Freshwater Invertebrate Invasiveness Scoring Kit and AmphISK- Amphibian Invasiveness Scoring Kit. These tool kits were developed by Cefas, with new VisualBasic and computational programming by Lorenzo Vilizzi, David Cooper, Andy South and Gordon H. Copp, based on VisualBasic code in the original Weed Risk Assessment (WRA) tool kit of P.C. Pheloung, P.A. Williams & S.R. Halloy (1999).
The decision support tools are available from: http://cefas.defra.gov.uk/our-science/ecosystems-and-biodiversity/non-native-species/decision-support-tools.aspx [Accessed 13 October 2011]
The guidance document is available from http://www.cefas.co.uk/media/118009/fisk_guide_v2.pdf [Accessed 13 January 2009].
8. Cole, R. 2002. Impacts of marine farming on wild fish populations. National Institute of Water and Atmospheric Research.
10. Crossman, E. J. 1991. Introduced Freshwater Fishes: A Review of the North American Perspective With Emphasis on Canada. Can. J. Fish. Aquat. Sci., Vol. 48 (Suppl. 1), 1991.
12. Gajardo, G & L Laikre., 2003. Chilean aquaculture boom isbased on exotic salmon resources: a conservation paradox. Conservation Biology 17: 1173-1174.
14. Institute of Freshwater Research. 2002. Performance and Ecological Impacts of Introduced and Escaped fish: Physiological and Behavioral Mechanisms. National Board OF Fisheries, Sweden. Goteborg Univserity.
16. Iriarte, J. Augustin Gabriel A. Lobos & Fabian M. Jaksic., 2005. Invasive vertebrate species in Chile and their control and monitoring by governmental agencies. Revista Chilena de Historia Natural 78: 143-154, 2005
17. Mendoza, R.E.; Cudmore, B.; Orr, R.; Balderas, S.C.; Courtenay, W.R.; Osorio, P.K.; Mandrak, N.; Torres, P.A.; Damian, M.A.; Gallardo, C.E.; Sanguines, A.G.; Greene, G.; Lee, D.; Orbe-Mendoza, A.; Martinez, C.R.; and Arana, O.S. 2009. Trinational Risk Assessment Guidelines for Aquatic Alien Invasive Species. Commission for Environmental Cooperation. 393, rue St-Jacques Ouest, Bureau 200, Montréal (Québec), Canada. ISBN 978-2-923358-48-1.
Summary: In 1993, Canada, Mexico and the United States signed the North American Agreement on Environmental Cooperation (NAAEC) as a side agreement to the North American Free Trade Agreement (NAFTA). The NAAEC established the Commission for Environmental Cooperation (CEC) to help the Parties ensure that improved economic efficiency occurred simultaneously with
trinational environmental cooperation. The NAAEC highlighted biodiversity as a key area for trinational cooperation. In 2001,
the CEC adopted a resolution (Council Resolution 01-03), which created the Biodiversity Conservation Working Group (BCWG),
a working group of high-level policy makers from Canada, Mexico and the United States. In 2003, the BCWG produced
the “Strategic Plan for North American Cooperation in the Conservation of Biodiversity.” This strategy identified responding to
threats, such as invasive species, as a priority action area. In 2004, the BCWG, recognizing the importance of prevention in addressing
invasive species, agreed to work together to develop the draft CEC Risk Assessment Guidelines for Aquatic Alien Invasive
Species (hereafter referred to as the Guidelines). These Guidelines will serve as a tool to North American resource managers
who are evaluating whether or not to introduce a non-native species into a new ecosystem. Through this collaborative
process, the BCWG has begun to implement its strategy as well as address an important trade and environment issue. With increased
trade comes an increase in the potential for economic growth as well as biological invasion, by working to minimize the potential adverse
impacts from trade, the CEC Parties are working to maximize the gains from trade while minimizing the environmental costs.
Available from: English version: http://www.cec.org/Storage/62/5516_07-64-CEC%20invasives%20risk%20guidelines-full-report_en.pdf [Accessed 15 June 2010]
French version: http://www.cec.org/Storage/62/5517_07-64-CEC%20invasives%20risk%20guidelines-full-report_fr.pdf [Accessed 15 June 2010]
Spanish version: http://www.cec.org/Storage/62/5518_07-64-CEC%20invasives%20risk%20guidelines-full-report_es.pdf [Accessed 15 June 2010].
18. Moffitt, C. M. 2003. The Implications of Aquaculture Production and Development on Sustainable Fisheries. U.S. Geological Survey, Idaho Cooperative Fish and Wildlife Research Unit, Department of Fish and Wildlife Resources, University of Idaho.
19. Naylor, Rosamond L., Susan L. Williams, Donald R. Strong., 2001. Aquaculture--A Gateway for Exotic Species. Science 23 November 2001: Vol. 294. no. 5547, pp. 1655 - 1656 DOI: 10.1126/Science.1064875
20. Naylor, Rosamond; Hindar, Kjetil; Fleming, Ian A.; Goldburg, Rebecca; Volpe, John; Whoriskey, Fred; Eagle, Josh; Kelso, Dennis; Mangel, Marc; Williams, Susan. 2005. Fugitive Salmon: Assessing the Risks of Escaped Fish from Net-Pen Aquaculture. Bioscience, May2005, Vol. 55 Issue 5, p427-437, 11p, 1 chart, 1 graph; (AN 16978376)
21. Olaussen, Jon Olaf; Skonhoft, Anders., 2008. On The Economics of Biological Invasion: An Application to Recreational Fishing. Natural Resource Modeling. 21(4). WIN 2008. 625-653
22. Pedersen, S., G. Rasmussen & E. E. Nielssen, L . Karlsson & P . Nybergs., 2007. Straying of Atlantic salmon, Salmo salar, from delayed and coastal releases in the Baltic Sea, with special focus on the Swedish west coast. Fisheries Management and Ecology, 2007, 14, 21–32
26. Volpe, J. Undated. Super un-Natural Atlantic Salmon in BC Waters. The David Suzuki Foundation.
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