Salmon Farming Benefits
Do the benefits of salmon farming outweigh any detrimental effects?
Worldwide, the salmon farming industry has witnessed extraordinary growth since the 1980’s with Chile, Canada, Norway and UK emerging as some of the largest producers (Eagle et al, 2004). Salmon farming is the process of harvesting salmon in cages or pens, usually offshore, as opposed to traditional capture fisheries.The economic and food production benefits of salmon farming (Salmo salar) will first be discussed. However there are many detrimental effects of salmon farming and this essay will predominantly take the position that the detrimental effects of salmon farming are far greater than the economic and food provision benefits. This will done by primarily focusing on …show more content…
the impact upon wild salmon stocks, as well as a brief overview of a few more general ecological impacts.
The main benefits of salmon farming are economic related. Salmon farming provides employment to people in isolated areas where employment is not as easy to find, such as the Highlands of Scotland. It can also benefit the local economies – between 2006 and 2011, £35.7 million of capital investment was invested by SSPO (Scottish salmon producers organisation) companies, in Argyll and Bute alone. Furthermore, 2124 people were directly employed by salmon farming in Scotland (SSPO, 2012). In terms of providing food for people, salmon farming as an intensive farming system is efficient. Improving food security and reducing world hunger is a key component of the FAOs visions for the future and aquaculture looks likely to play a key role in meeting future demand for food. When compared to capture salmon fisheries, salmon farming is more predictable and greater control of production quantity is possible. In 2012, capture fisheries produced 90.6 million tonnes, while aquaculture produced 66.3 million tonnes ( FAO,2013). However a
The escape of farmed salmon into seas and rivers are common in the aquaculture industry and there are concerns over the potential for negative interactions between escapees and wild salmon. This can occur through general ‘leakage’ through holes in nets and cages and through stormy weather, where moorings and gear may be damaged (Green et al, 2012). In January 2014, Meridian Salmon Farms Ltd reported the escape of 154,589 salmon in Yell, Shetland, due to weather causing a mooring failure. In many cases, none of the escaped fish are recovered (A Marine Scotland, 2014). Schiermeier (2003) estimated the number of farmed Atlantic salmon escapes at 2 million per year. Escaped farmed salmon compete with wild salmon for resources and inter-breed with native wild salmon in the Atlantic. Experiments have shown that farmed salmon are genetically different from wild salmon through several features such as reduced allelic diversity. Thus, there are concerns that repeated escape events could lead to loss of genetic distinctiveness of the wild salmon populations. The same experiment concluded that farmed salmon had lifetime reproductive success which was 16% that of wild salmon (Hindar et al, 2006). Studies have shown that the offspring of a farmed/ hybrids (hybrids resulted from wild x farmed crosses) cross exhibited decreased survival and fitness. Therefore long-term interbreeding between farmed and wild salmon could lead to overall decreased fitness and extinction of wild salmon stocks (McGinity et al, 2003). Further to this, open-net salmon farms can affect nearby wild salmon without the necessity for escaped fish.
There is a general consensus that open – net salmon farms are having a detrimental effect on wild salmon populations by increasing sea lice infections rates. The sea lice Caligus elongates (Nordmann, 1832) and Lepeophtheirus salmonis (Kroyer, 1837) are both found in Scottish waters. Copepepodids are the infectious stage and attach to the skin of hosts, where they feed on blood and mucus (Ingvarsdottir et al, 2002). Salmon farms can be very intensive systems with high stocking densities and the welfare of farmed salmon is thought to decrease at stocking densities above 25kg m-3 (Turnball et al, 2005). Farming fish at such high densities is common and inevitably causes problems, as farm cages can act as breeding grounds for sea lice. In open-pen systems the sea lice multiply and spread into adjacent waters. Thus, any juvenile fish migrating from rivers which are in the vicinity of the farms are faced with a barrage of sea lice and are attacked (Butler and Watt, 2007). Many of the offshore salmon farms are located along coastlines close to river mouths and the proximity of wild salmon to salmon farms are thought to be a key factor influencing infection rates of wild salmon by sea lice. A study by Morton et al (2004) demonstrated this during an experiment in British Columbia, where sea lice abundance was 8.8X greater in wild pink salmon that were located near to salmon farms, than those which were not near salmon farms. Krkoesk et al (2011) found that while small increased infection rates (3 lice per fish) may not always directly increase mortality, it does cause salmon to undertake greater predation risks during foraging. Therefore salmon farms are greatly exacerbating the risk that sea lice pose to wild salmon populations.
The issues associated with such intensive farming methods are also manifested in increased occurrence of diseases and broader ecological damage.
Cataracts are common in the industry and in one study, Wall (1998) observed cataracts in 50-90% of Irish salmon. It has been suggested that many of these health problems stem from inadequate water and food & nutrition quality (Wall, 1998). Viral diseases such as infectious pancreatic necrosis are also prevalent in Norwegian and Scottish farms (Ruane et al, 2007). Thus, the health of farmed salmon can be far from ideal and this calls into question how welfare- friendly rearing farmed salmon is. Waste organic material from the farms can build up on the benthos below cages which results in shifts in the community structure and sedimentation, generally leading to decreased taxa abundance or an ‘azoic zone’. Meiofaunal communities can take in excess of 4 months to fully recover (Mazzola et al , 2000). One of the more contentious issues surrounding salmon farming is the licenced shooting of seals, to decrease seal predation. In 2014, a maximum of 1,005 seals were licensed to be shot in Scotland, primarily for protection of fish farms (B Marine Scotland, 2014). Therefore, there is a vast array of negative impacts instigated by current practices in salmon …show more content…
farming.
To conclude, aquaculture has outcompeted traditional salmon fishing methods and is aggravating the depletion in the traditional wild S.salar fishery, rather than acting to support and supplement it. However, the detrimental effects of salmon farming have to be balanced with the local and worldwide economic benefits and demand for food and ultimately, the end judgement depends on the priorities and goals of the industry. Furthermore, the aquaculture industry is still relatively young and there is still scope to tackle and provide solutions to issues such as those discussed and salmon farming as a whole should not be condemned.
References A Marine Scotland, 2014. Confirmed Reported Escapes from Fish Farms in Scotland (database). Availableat:http://www.scotland.gov.uk/Topics/marine/Fish-Shellfish/18364/18692/escapeStatistics>.[ Accessed 20th April 2014].
B Marine Scotland, 2014. 2014 Seal Licences. Available at: < http://www.scotland.gov.uk/Topics/marine/Licensing/SealLicensing>. [Accessed 24th April, 2014]
Butler, J.R.A. and Watt, J. 2007. Assessing and Managing the Impacts of Marine Salmon Farms on Wild Atlantic Salmon in Western Scotland: Identifying Priority Rivers for Conservation, in Salmon at the Edge (Ch.9) (ed D. Mills), Blackwell Science Ltd., Oxford, UK.
Green, D.M., Penman, D.J.,Migaud, H., Bron, J.E., Taggart, J.B., McAndrew, B.J. 2012 . The Impact of Escaped Farmed Atlantic Salmon (Salmo salar L.) on Catch Statistics in Scotland. Plosone.7(9): pp.1-8.
Eagle, J., Naylor, R., Smith, W. 2004. Why farm salmon outcompete fishery salmon. Marine Policy.28 (3):pp 259-270.
FAO. 2013. Food Outlook: Biannual report on global food markets. p8.
Hindar, J., Fleming., I.A., McHinitty, P., Diserud, O.
2006. Genetic and ecological effects of salmon farming on wild salmon: modelling from experimental results. ICES Journal of Marine Science. 63:pp 1234-1247.
Ingvarsdottir, A., Birkett, M., Duce, I., Genna, R.L., Mordue, W., Pickett, J.A., Wadhams, L.J., Mordue, J.A. 2002. Semiochemical strategies for sea louse control: host location cues. Pest Management Science. 58 (6): pp 537-545. Krkošek, M., Connors, B.M., Ford, H., Peacock, S., Mages, P., Ford, J.S., Morton, A.,Volpe, J.P., Hilborn, R., Dill, L.M., Lewis, M.A. 2011. Fish farms, parasites, and predators: implications for salmon population dynamics. Ecological Applications 21: pp897–914.
Mazzola, A., Mirto, S., La Rosa, T., Fabiano, M., Danovaro, R. 2000. Fish- farming effects on benthic community structure in coastal seddiments: analysis of meiofaunal recovery. ICES Jounal of Marine Science. 57: pp. 1454-1461.
McGinnity, P., Prodohl, P., Ferguson, A., Hynes, R., Maoileidigh, N.O., Baker, N, Cotter, D., O’Hea, B., Cooke, D., Rogan, G., Taggart, J., Cross, T. 2003. Fitness reduction and potential extinction of wild populations of Atlantic salmon, Salmo salar, as a result of interactions with escaped farmed salmon. Proceedings of the Royal Society of Biological Sciences. 270 (1532): pp
2443-2450.
Morton, A., Routledge, R., Peet, C., Ladwig, A. 2004. Sea lice (Lepepphtheirus salmonis) infection rats on juvenile pink (Oncorhynchus gorbuscha) and chum (Oncorhynchus keta) salmon in the nearshore marine environment of British Columbia, Canada. Can. J. Fish. Aquat. Sci. 61: pp 147-157.
Ruane, N., Geoghedgan, F., O’ Cinneide, M. 2007. Infectious pancreatic necrosis virus and its impact on the Irish salmon aquaculture and wild fish sectors. Marine Environment & Health Series. No. 30.
SSPO, 2012. Scottish Salmon Farming: Industry Research Report.
Schiermeier, Q. 2003. Fish farm’s threats to salmon stocks exposed. Nature. 425:p 753.
Turnball, J., Bell, A., Adams, C., Bron, J., Huntingford, F. 2004 . Stocking density and welfare of cage farmed Atlantic salmon: application of multivariate analysis. Aquaculture. 243 : pp. 121-132.
Wall, 1998. Cataracts in farmed Atlantic salmon (Salmo salar) in Ireland, Norway and Scotland from 1995 to 1997. Veterinary Record. 142(23): pp. 626-631.
Worldwide, the salmon farming industry has witnessed extraordinary growth since the 1980’s with Chile, Canada, Norway and UK emerging as some of the largest producers (Eagle et al, 2004). Salmon farming is the process of harvesting salmon in cages or pens, usually offshore, as opposed to traditional capture fisheries.The economic and food production benefits of salmon farming (Salmo salar) will first be discussed. However there are many detrimental effects of salmon farming and this essay will predominantly take the position that the detrimental effects of salmon farming are far greater than the economic and food provision benefits. This will done by primarily focusing on …show more content…
the impact upon wild salmon stocks, as well as a brief overview of a few more general ecological impacts.
The main benefits of salmon farming are economic related. Salmon farming provides employment to people in isolated areas where employment is not as easy to find, such as the Highlands of Scotland. It can also benefit the local economies – between 2006 and 2011, £35.7 million of capital investment was invested by SSPO (Scottish salmon producers organisation) companies, in Argyll and Bute alone. Furthermore, 2124 people were directly employed by salmon farming in Scotland (SSPO, 2012). In terms of providing food for people, salmon farming as an intensive farming system is efficient. Improving food security and reducing world hunger is a key component of the FAOs visions for the future and aquaculture looks likely to play a key role in meeting future demand for food. When compared to capture salmon fisheries, salmon farming is more predictable and greater control of production quantity is possible. In 2012, capture fisheries produced 90.6 million tonnes, while aquaculture produced 66.3 million tonnes ( FAO,2013). However a
The escape of farmed salmon into seas and rivers are common in the aquaculture industry and there are concerns over the potential for negative interactions between escapees and wild salmon. This can occur through general ‘leakage’ through holes in nets and cages and through stormy weather, where moorings and gear may be damaged (Green et al, 2012). In January 2014, Meridian Salmon Farms Ltd reported the escape of 154,589 salmon in Yell, Shetland, due to weather causing a mooring failure. In many cases, none of the escaped fish are recovered (A Marine Scotland, 2014). Schiermeier (2003) estimated the number of farmed Atlantic salmon escapes at 2 million per year. Escaped farmed salmon compete with wild salmon for resources and inter-breed with native wild salmon in the Atlantic. Experiments have shown that farmed salmon are genetically different from wild salmon through several features such as reduced allelic diversity. Thus, there are concerns that repeated escape events could lead to loss of genetic distinctiveness of the wild salmon populations. The same experiment concluded that farmed salmon had lifetime reproductive success which was 16% that of wild salmon (Hindar et al, 2006). Studies have shown that the offspring of a farmed/ hybrids (hybrids resulted from wild x farmed crosses) cross exhibited decreased survival and fitness. Therefore long-term interbreeding between farmed and wild salmon could lead to overall decreased fitness and extinction of wild salmon stocks (McGinity et al, 2003). Further to this, open-net salmon farms can affect nearby wild salmon without the necessity for escaped fish.
There is a general consensus that open – net salmon farms are having a detrimental effect on wild salmon populations by increasing sea lice infections rates. The sea lice Caligus elongates (Nordmann, 1832) and Lepeophtheirus salmonis (Kroyer, 1837) are both found in Scottish waters. Copepepodids are the infectious stage and attach to the skin of hosts, where they feed on blood and mucus (Ingvarsdottir et al, 2002). Salmon farms can be very intensive systems with high stocking densities and the welfare of farmed salmon is thought to decrease at stocking densities above 25kg m-3 (Turnball et al, 2005). Farming fish at such high densities is common and inevitably causes problems, as farm cages can act as breeding grounds for sea lice. In open-pen systems the sea lice multiply and spread into adjacent waters. Thus, any juvenile fish migrating from rivers which are in the vicinity of the farms are faced with a barrage of sea lice and are attacked (Butler and Watt, 2007). Many of the offshore salmon farms are located along coastlines close to river mouths and the proximity of wild salmon to salmon farms are thought to be a key factor influencing infection rates of wild salmon by sea lice. A study by Morton et al (2004) demonstrated this during an experiment in British Columbia, where sea lice abundance was 8.8X greater in wild pink salmon that were located near to salmon farms, than those which were not near salmon farms. Krkoesk et al (2011) found that while small increased infection rates (3 lice per fish) may not always directly increase mortality, it does cause salmon to undertake greater predation risks during foraging. Therefore salmon farms are greatly exacerbating the risk that sea lice pose to wild salmon populations.
The issues associated with such intensive farming methods are also manifested in increased occurrence of diseases and broader ecological damage.
Cataracts are common in the industry and in one study, Wall (1998) observed cataracts in 50-90% of Irish salmon. It has been suggested that many of these health problems stem from inadequate water and food & nutrition quality (Wall, 1998). Viral diseases such as infectious pancreatic necrosis are also prevalent in Norwegian and Scottish farms (Ruane et al, 2007). Thus, the health of farmed salmon can be far from ideal and this calls into question how welfare- friendly rearing farmed salmon is. Waste organic material from the farms can build up on the benthos below cages which results in shifts in the community structure and sedimentation, generally leading to decreased taxa abundance or an ‘azoic zone’. Meiofaunal communities can take in excess of 4 months to fully recover (Mazzola et al , 2000). One of the more contentious issues surrounding salmon farming is the licenced shooting of seals, to decrease seal predation. In 2014, a maximum of 1,005 seals were licensed to be shot in Scotland, primarily for protection of fish farms (B Marine Scotland, 2014). Therefore, there is a vast array of negative impacts instigated by current practices in salmon …show more content…
farming.
To conclude, aquaculture has outcompeted traditional salmon fishing methods and is aggravating the depletion in the traditional wild S.salar fishery, rather than acting to support and supplement it. However, the detrimental effects of salmon farming have to be balanced with the local and worldwide economic benefits and demand for food and ultimately, the end judgement depends on the priorities and goals of the industry. Furthermore, the aquaculture industry is still relatively young and there is still scope to tackle and provide solutions to issues such as those discussed and salmon farming as a whole should not be condemned.
References A Marine Scotland, 2014. Confirmed Reported Escapes from Fish Farms in Scotland (database). Availableat:http://www.scotland.gov.uk/Topics/marine/Fish-Shellfish/18364/18692/escapeStatistics>.[ Accessed 20th April 2014].
B Marine Scotland, 2014. 2014 Seal Licences. Available at: < http://www.scotland.gov.uk/Topics/marine/Licensing/SealLicensing>. [Accessed 24th April, 2014]
Butler, J.R.A. and Watt, J. 2007. Assessing and Managing the Impacts of Marine Salmon Farms on Wild Atlantic Salmon in Western Scotland: Identifying Priority Rivers for Conservation, in Salmon at the Edge (Ch.9) (ed D. Mills), Blackwell Science Ltd., Oxford, UK.
Green, D.M., Penman, D.J.,Migaud, H., Bron, J.E., Taggart, J.B., McAndrew, B.J. 2012 . The Impact of Escaped Farmed Atlantic Salmon (Salmo salar L.) on Catch Statistics in Scotland. Plosone.7(9): pp.1-8.
Eagle, J., Naylor, R., Smith, W. 2004. Why farm salmon outcompete fishery salmon. Marine Policy.28 (3):pp 259-270.
FAO. 2013. Food Outlook: Biannual report on global food markets. p8.
Hindar, J., Fleming., I.A., McHinitty, P., Diserud, O.
2006. Genetic and ecological effects of salmon farming on wild salmon: modelling from experimental results. ICES Journal of Marine Science. 63:pp 1234-1247.
Ingvarsdottir, A., Birkett, M., Duce, I., Genna, R.L., Mordue, W., Pickett, J.A., Wadhams, L.J., Mordue, J.A. 2002. Semiochemical strategies for sea louse control: host location cues. Pest Management Science. 58 (6): pp 537-545. Krkošek, M., Connors, B.M., Ford, H., Peacock, S., Mages, P., Ford, J.S., Morton, A.,Volpe, J.P., Hilborn, R., Dill, L.M., Lewis, M.A. 2011. Fish farms, parasites, and predators: implications for salmon population dynamics. Ecological Applications 21: pp897–914.
Mazzola, A., Mirto, S., La Rosa, T., Fabiano, M., Danovaro, R. 2000. Fish- farming effects on benthic community structure in coastal seddiments: analysis of meiofaunal recovery. ICES Jounal of Marine Science. 57: pp. 1454-1461.
McGinnity, P., Prodohl, P., Ferguson, A., Hynes, R., Maoileidigh, N.O., Baker, N, Cotter, D., O’Hea, B., Cooke, D., Rogan, G., Taggart, J., Cross, T. 2003. Fitness reduction and potential extinction of wild populations of Atlantic salmon, Salmo salar, as a result of interactions with escaped farmed salmon. Proceedings of the Royal Society of Biological Sciences. 270 (1532): pp
2443-2450.
Morton, A., Routledge, R., Peet, C., Ladwig, A. 2004. Sea lice (Lepepphtheirus salmonis) infection rats on juvenile pink (Oncorhynchus gorbuscha) and chum (Oncorhynchus keta) salmon in the nearshore marine environment of British Columbia, Canada. Can. J. Fish. Aquat. Sci. 61: pp 147-157.
Ruane, N., Geoghedgan, F., O’ Cinneide, M. 2007. Infectious pancreatic necrosis virus and its impact on the Irish salmon aquaculture and wild fish sectors. Marine Environment & Health Series. No. 30.
SSPO, 2012. Scottish Salmon Farming: Industry Research Report.
Schiermeier, Q. 2003. Fish farm’s threats to salmon stocks exposed. Nature. 425:p 753.
Turnball, J., Bell, A., Adams, C., Bron, J., Huntingford, F. 2004 . Stocking density and welfare of cage farmed Atlantic salmon: application of multivariate analysis. Aquaculture. 243 : pp. 121-132.
Wall, 1998. Cataracts in farmed Atlantic salmon (Salmo salar) in Ireland, Norway and Scotland from 1995 to 1997. Veterinary Record. 142(23): pp. 626-631.