Another environmental impact is with the impact on wild salmon. The aquaculture industry argues that farmed salmon eases pressure on wild stocks. Theoretically, this may be true but in practice the argument lacks strength. Wild salmon stocks are subject to quotas and active management from the Department of Fisheries, and the global overfishing problem is not necessarily related to wild salmon stocks. There is no evidence presented that demand for wild salmon decreases as the result of the increased availability of farmed salmon.
Most farmed salmon are Atlantic salmon, which are preferred by the industry for a couple of reasons. These salmon are not native to British Columbia. Specimens do escape from fish farms, and this creates significant risk to local species. On the Atlantic Coast, wild stocks of Atlantic salmon are listed as critically endangered, and can be put at risk by escaped farm fish. In British Columbia, the Atlantic salmon is an invasive species and can take over local waterways, reducing the environment for local salmon species (p.8). Further, local species can be put at risk through the transmission of disease from fish farms. The high density of fish in aquaculture locations facilitates the transfer of pathogen (p.8), including sea lice. Sea lice can affect juvenile wild salmon that are entering the ocean for the first time, and can cause them death. Speculation has even held that sea lice have reduced wild salmon returns, although there is no evidence for that. The environment surrounding fish farms is also put at risk due to the use of various chemicals and pollutants in the production of farmed salmon. These include PCBs, dioxins and other "persistent organic pollutants" (p.8).
The most significant of these environmental risks is to wild salmon stocks and to the local environment. The risk of Atlantic salmon escaping is high, due to adverse weather, broken nets or human error. The industry does not appear to have adequately addressed these risks. The risks associated with sea lice and fish waste have received insufficient response from the industry. Part of the problem may lie with current regulations, but part of the problem may also lie with enforcement, since most aquaculture in British Columbia is conducted in remote locations.
The current debate about aquaculture is highly-charged emotionally, but lacks significant basic information. Much of the science surrounding aquaculture has been contested by different stakeholders, so remains largely inconclusive. When dealing in environmental policy, the key is to understand the risks. The absence of information, or reliable information, may make it more difficult to determine specific risk levels, but the absence of information also does not reduce risk. If anything, inadequate information increases risk, because risk is that which is uncertain.
From an environmental policy perspective, the best response to risk is to reduce it. There are several steps that can be undertaken. First, the risk that stems from inadequate information should be addressed with further studies that provide more information. If the industry and environmental groups cannot be trusted to provide accurate information, then the government should seek it out. This will be a challenge given the Harper government's aversion to scientific research, however, so we may not be able to move quickly to get the knowledge we need.
There are other ways, however, to reduce risk. Known risks like escaped fish can be addressed through tougher standards and safeguards, and through more better enforcement mechanisms. Better nets, better standards with respect to the ability of fish farms to handle violent weather, and better controls over mechanical and human error would all decrease risk. The industry has demonstrated an aversion to any regulation that will cost it money, so the environment will benefit from cutting the industry out of the discussion -- they are not oriented towards environmental improvement so are an obstacle rather than an aid. Additionally, if regulations are needed on the types of feed used, or with respect to the management of sea lice, these can be implemented. More likely, however, those issues will need further study before the risks associated with waste or lice can be fully understood. With these strategies, it is believed that the environmental risks associated with aquaculture in British Columbia can be reduced.
Young, Nathan. & Matthews, Ralph. (2010). The aquaculture controversy in Canada: Activism, policy and contested…