Effects of Salmon Farming on North American Wild Salmon Resources

Transcription

1 CHAPTER XIX Effects of Salmon Farming on North American Wild Salmon Resources Key Points The potential direct effects of salmon farming on wild resources differ for different wild salmon producing regions of North America. How salmon farming might affect wild salmon resources depends in part on whether farmed species are native to the region. In the Northeast, both wild salmon and farmed salmon are Atlantic salmon, while in the other regions wild salmon are Pacific salmon while most farmed salmon are Atlantic salmon. In the Northeast, because wild and farmed salmon are the same species, there is relatively greater risk of genetic interaction between farmed and wild salmon and for transmission of diseases. In other regions, there is a risk of establishment of non-native Atlantic salmon. Potential direct effects salmon farming might have on wild salmon resources also depend on the proximity of salmon farms to wild salmon migration routes. North American salmon farming operations are concentrated in relatively small areas compared to the range of North American Introduction In earlier chapters, we have examined the economic and social effects of salmon farming on the wild salmon industry, and marketing and trade issues to which they have given rise. In this chapter, we look briefly at the effects of salmon farming on North American wild salmon resources. Salmon farming may potentially affect wild salmon resources in many different ways, both directly and indirectly. Potential direct effects of salmon farming on wild salmon resources would occur as a result of interactions in the environment between farmed salmon operations and wild salmon. These include possible transmission of diseases, genetic interactions between wild fish and escaped farmed fish, or the introduction of non-native species which might compete with native wild salmon species. The extent to which these effects wild salmon resources. The largest wild salmon runs, in Alaska, are located great distances from any salmon farms. In theory, salmon farming could benefit wild salmon resources if salmon farming caused lower market prices which in turn led to lower commercial catches for over-fished wild salmon runs (Anderson 1985). But lower prices will not necessarily lead to lower catches, because in most wild salmon fisheries it would be possible to catch the available fish at lower cost by using fewer boats or more efficient gear. And lower catches would not necessarily benefit wild salmon resources, because the largest commercial salmon fisheries are not over-fished. Lower prices caused by farmed salmon could reduce the profitability of hatchery operations and erode political support for hatcheries, leading to a decline in hatchery releases. Potentially this could benefit natural wild salmon resources, to the extent that hatchery releases represent a risk to wild salmon stocks, as some critics allege. have occurred or might occur is controversial, and has been the subject of considerable debate. As economists, we have no independent expertise to add to this debate. We do not attempt to say what direct effects have occurred or might occur. Instead, we point out the differences in the relative potential significance of these effects for different salmon producing regions. Potential indirect effects of salmon farming on wild salmon resources include changes in wild salmon catches, commercial hatchery releases and commitment to managing wild salmon resources for commercial fishing. In theory, some indirect effects might be positive while others might be negative. Both the potential direct and indirect effects of salmon farming on wild salmon resources are uncertain. Clearly they vary widely between different salmon producing regions and for different species of salmon. Traffic North America 271

2 We cannot give any definitive answers about how significant these effects have been or might be in the future. Our goal is to provide a framework for thinking systematically about these potential effects. Potential Direct Effects of Salmon Farming on Wild Salmon Resources Table XIX-1 summarizes several potential direct effects of salmon farming on wild salmon resources. The potential significance of these effects varies for different wild salmon producing regions, for several reasons. How salmon farming might affect wild salmon resources depends in part on whether the species are native to the region. If farmed species are native to the region the same species as local wild salmon then there is greater potential for escaped farm fish to interbreed with or out-compete wild fish, thus affecting the genetic diversity of wild salmon stocks. 1 Presumably there is also greater potential for transmission of disease 2, although this may not be the case for all diseases. In contrast, if farmed species are not native to the region, then there is a risk that escaped farmed fish could become established in the region, with unknown ecological effects. Table XIX-1 Potential Direct Effects of Salmon Farming on North American Wild Salmon Resources Factors affecting Potential Significance of Effect, by Region* potential significance Potential mechanisms of effect Northeast Northwest British Columbia Alaska Introduction of non- Native salmon species which compete with Native salmon species - -?? - -?? - -?? Whether farmed species Farmed Atlantic to Farmed Atlantic Farmed Atlantic Farmed Atlantic are Native to region salmon are Native salmon are not salmon are not salmon are not region Native to region Native to region Native to region Number of escaped farmed fish Low Varied, but declining Very low Potential for establishment of non-native species Uncertain Uncertain Uncertain Interbreeding between escaped farmed fish and wild fish resulting in loss of genetic diversity in wild stocks - -?? Whether farmed Both farmed and Farmed fish are Farmed fish are Escaped farmed fish species are the same wild fish are mostly Atlantic mostly Atlantic from other regions as wild species Atlantic salmon salmon; wild fish salmon; wild fish are mostly Atlantic are Pacific salmon are Pacific salmon salmon; wild fish are Pacific salmon Number of escaped Number of Atlantic Number of Pacific Number of Pacific Number of Pacific fish relative to wild salmon escapes is salmon escapes salmon escapes salmon escapes populations moderate relative is very small relative is very small relative is very small relative to wild populations to wild populations to wild populations to wild populations Transmission of disease from farmed fish to wild fish - -? -? Proximity of farms to wild Some wild salmon Most wild salmon runs Some wild salmon There are no salmon migration routes runs are near farms are not near farms runs are near farms salmon farms Extent of disease in farmed There have been There have been There have been salmon stocks significant disease some disease some disease problems problems problems Whether farmed species Both farmed and wild Farmed fish are wild Farmed fish are wild are the same as wild fish are Atlantic mostly Atlantic mostly Atlantic species salmon salmon; fish are salmon; fish are Pacific salmon Pacific salmon; Note: - denotes a negative effect; - - denotes a very negative effect.? denotes that the effect is uncertain;?? denotes that the effect is very uncertain. 1 Potential effects on genetic diversity also depend on whether farmed fish are from local runs or from other areas as with salmon hatcheries. 2 Transmission of disease can go both ways farmed salmon can transmit disease to wild salmon, but there have also been cases where wild salmon have transferred disease to the farmed stock. 272 The Great Salmon Run: Competition Between Wild and Farmed Salmon

3 The relative potential significance of these two effects varies between the Northeast and Canadian Maritimes and other wild salmon producing regions, because in the Northeast both wild salmon and farmed salmon are Atlantic salmon, while in the other regions wild salmon are Pacific salmon while most farmed salmon are Atlantic salmon. Put differently, salmon farms in the Northeast presumably pose relatively greater likelihood of change in the genetic diversity of local wild salmon stocks and for transmission of disease to local wild salmon stocks, while salmon farms in the Northwest pose a risk of introduction of non-native Atlantic salmon. How salmon farming might affect wild salmon resources also clearly depends on the proximity of salmon farms to wild salmon migration routes. Although there is some risk of disease transmission from farmed fish to wild stocks and from wild stocks to farmed salmon, clearly the risk of disease transmission is greater closer to salmon farms. North American salmon farming operations are concentrated in relatively small areas compared to the range of North American wild salmon resources. While some wild salmon migration routes are close to salmon farms in parts of Maine, New Brunswick, Nova Scotia, Puget Sound and British Columbia most wild salmon never come near salmon farms, including almost all of the Alaska wild salmon which account for most North American commercial wild salmon catches, as well as the wild salmon returning to Newfoundland, Labrador, the Columbia River basin and California. 3 Potential Indirect Effects of Salmon Farming on Wild Salmon Resources Potential indirect effects of salmon farming on wild salmon resources are those which might occur as a result of economic, social and political effects of salmon farming on the wild salmon industry, wild salmon commercial hatcheries and wild salmon management. Table XIX-2 summarizes some of these potential effects. As with direct effects, these indirect effects are complex, uncertain and difficult to quantify. However, their potential significance clearly varies for different wild-salmon producing regions. Wild Salmon Catches In theory, salmon farming could have a positive effect on wild salmon resources if salmon farming caused a reduction in wild salmon catches for salmon runs which would otherwise have been over-fished (Anderson, 1985). For this to happen, the following three effects would have to occur: Salmon farming causes prices to fall for wild salmon Lower prices result in lower wild salmon catches Lower wild salmon catches benefit wild salmon resources The first of these effects has occurred. Salmon farming has caused wild salmon prices to fall (although it has not been the sole factor causing prices to fall). However, the second effect has not occurred to any significant extent, nor is it necessarily likely to occur in the future. Fewer permits are being fished, but not to an extent where wild salmon catches are decreasing. Ordinarily, we would expect lower prices to result in lower catches in a wild fishery. However, this will not necessarily be the case in overcapitalized limited entry salmon fisheries, such as some Alaska salmon fisheries. To understand why, recall that these fisheries are regulated by managers to achieve goals for escapement, or the number of returning salmon which enter rivers to spawn. Any returning salmon above the escapement goal are considered surplus and available for harvest. Managers adjust the fishing opportunities in-season to allow boats to catch these surplus fish. Therefore, even if fewer boats fish or they fish less intensively, catches do not necessarily decline, because managers can increase fishing opportunities to adjust for the lower effort. In this kind of fishery, as prices first begin to decline, lower prices result in lower profits, but all boats continue to fish. As prices further decline, some boats may leave the fishery, but the remaining boats are able to catch all of the available fish and lower prices are partially offset by higher average catches. As prices further decline and more boats leave the fishery, managers expand fishing opportunities for the remaining boats so that they can catch all of the available fish. Finally, if prices decline still further, political pressure is likely to lead to changes in fishery management to allow for the use of more efficient gear, such as salmon traps, which can catch fish at lower cost. Thus, lower prices may but not necessarily lead to lower wild salmon catches. In Alaska, British Columbia and the U.S. Pacific Northwest, there has been little systematic empirical analysis of the extent to which the decline in salmon prices has affected salmon catches or escapement. It is likely that the effects of the decline in prices on catches vary by fishery and species, and that the effects have been greatest for lower-valued species (such as some Alaska pinksalmon fisheries) as well as for remote, low-volume higher-cost fisheries (such as those of interior and northwestern Alaska). Even if prices fall far enough to cause wild salmon catches to fall, this will not necessarily benefit wild 3 Potential direct effects of salmon farming on wild resources in different regions are reviewed, from varying perspectives, in BC Environmental Assessment Office (2003); Gaudet (2001); Noakes et al. (2000); Volpe (2001); Waknitz et al. (2002); and Watershed Watch (2001). These are only a few examples from a large and growing literature debating the effects of salmon farming. Traffic North America 273

4 Table XIX-2 Potential Indirect Effects of Salmon Farming on North American Wild Salmon Resources Factors affecting Potential Significance of Effect, by Region* potential significance Potential mechanisms of effect Northeast Northwest British Columbia Alaska Reductions in commercial wild salmon catches due to lower profitability due to competition from farmed salmon +? +?? +?? Effect of commercial wild There are no salmon catches on wild commercial catches Uncertain, probably salmon resources of wild salmon Uncertain Uncertain small Extent of economic rents in Economic rents Economic rents are Economic rents are wild salmon fishing and are small small in some small in some processing fisheries but fisheries but significant in others significant in others Potential for increasing There is significant There is significant There is significant efficiency of wild salmon potential to increase potential to increase potential to increase fishing and processing efficiency in fishing efficiency in fishing efficiency in fishing Reductions in hatchery releases due to lower profitability due to competition from farmed salmon +? +?? +?? Scale of commercial There are no hatchery releases commercial hatchery Significant in some releases Significant Significant areas Effect of commercial hatchery releases on wild salmon resources Uncertain Uncertain Uncertain Profitability of commercial salmon enhancement Low Low Varied Reduced societal commitment to protection of wild salmon resources due to declining profitability of commercial industry -?? -?? Share of wild salmon benefits derived from There is no commercial industry commercial industry Relatively low Moderate Relatively high Economic tradeoffs between wild salmon resource protection and other activities (hydroelectricity, farming, etc.) Relatively high Moderate Relatively small Note: - denotes a negative effect; - - denotes a very negative effect; + denotes a positive effect; ++ denotes a very positive effect.? denotes that the effect is uncertain;?? denotes that the effect is very uncertain. salmon resources. As we discussed in Chapter II, the explicit goal of managers in most commercial wild salmon fisheries is to manage fish sustainably, so that catches do not adversely affect the harvest from wild salmon resources or the potential for future wild salmon catches. Note also that a decline in the number of boats fishing is most likely to cause a decline in catches in years of large salmon runs, when a smaller fleet may not be able to catch all of the available fish during peak periods of the run. However, reducing catches during years of large runs is less likely to benefit wild salmon resources. Lower catches would be more likely to benefit wild salmon resources during years of low runs, when escapement might otherwise be insufficient to meet spawning needs. In mixed stock salmon fisheries, where fish returning to different streams are swimming together, lower catches may benefit salmon runs other than those for which managers are setting escapement goals. In theory, any significant commercial catches have the potential to adversely affect small runs in mixed stock fisheries (Anderson 1985). Thus, in theory no commercial fishing is without some risk to some wild salmon 274 The Great Salmon Run: Competition Between Wild and Farmed Salmon

5 resources, and any reduction in wild salmon catches attributable to competition from farmed salmon would reduce these risks and thus tend to benefit these wild salmon resources. In general, although it is clear that salmon farming has contributed to lower prices for wild salmon, there is little empirical evidence to suggest that lower prices have significantly contributed to healthier wild salmon resources by reducing catches. The extent to which such effects may have occurred likely varies widely by fishery. Clearly, the potential significance of any reduction in over-fishing effect varies by region. In the Northeast, because there are no commercial wild salmon fisheries, there cannot be any benefit from any reduction in commercial catches. In Table XIX-2, we speculate that a farmed salmon-driven decline in prices might benefit some U.S. Pacific Northwest, British Columbia and Alaska salmon resources. Hatchery Releases As we discussed in Chapter IV, hatcheries account for a significant share of North American commercial wild salmon catches. There is an ongoing debate about potential adverse effects of hatchery releases on natural wild salmon runs. In theory, salmon farming could cause a reduction in hatchery releases by reducing the profitability of hatchery operations and eroding political support for hatcheries. In turn, a reduction in commercial hatchery releases could benefit natural wild salmon resources. Arguably, salmon farming may be partly responsible for the levelling off of Alaska hatchery releases during the 1990s after rapid growth in releases during the 1980s. Traffic North America 275

6 References Anderson, J.L Private Aquaculture and Commercial Fisheries: Bioeconomics of Salmon Ranching. Journal of Environmental Economics and Management. 12: British Columbia Environmental Assessment Office The Salmon Aquaculture Review Final Report. Gaudet, Dave Atlantic Salmon: A White Paper. Alaska Department of Fish and Game. Noakes, Donald J, Richard J. Beamish, and Michael L. Kent On the decline of Pacific salmon and speculative links to salmon farming in British Columbia. Aquaculture, 183: Volpe, John Super Un-Natural: Atlantic Salmon in BC Waters. David Suzuki Foundation. Waknitz, F.W., T.J. Tynan, C.E. Nash, R.N. Iwamoto, and L.G. Rutter Review of Potential Impacts of Atlantic Salmon Culture on Puget Sound Chinook Salmon and Hood Canal Summer-Run Chum Salmon Evolutionarily Significant Units. U.S. Department of Commerce, NOAA Technical Memorandum NMFS-NWFSC-53, 83 pages. Available on-line at the Northwest Fisheries Science Center web site ( Watershed Watch Salmon Farms, Sea Lice & Wild Salmon. 276 The Great Salmon Run: Competition Between Wild and Farmed Salmon