Science Response 2011/004

Wild Salmon Populations in the Vicinity of a Proposed Finfish Aquaculture Development at Little Musquash Cove, New Brunswick

Context

On December 6, 2010, Fisheries and Oceans Canada’s (DFO) Habitat Protection and Sustainable Development (HSPD) Division, Maritimes Region, requested that DFO Science, Maritimes Region, provide advice regarding wild salmon populations in the vicinity of a proposed finfish aquaculture development site at Little Musquash Cove, New Brunswick, as well as the likelihood of the proposed development project having negative impacts to the wild salmon populations and their habitat. The request for advice is in support of HPSD’s review of an environmental assessment (EA) of a proposed aquaculture development project pursuant to the Canadian Environmental Assessment Act. Specifically, DFO HPSD asked:

1. What wild salmon populations (and their lifecycle stages) are present in the vicinity of the proposed finfish aquaculture development site at Little Musquash Cove, New Brunswick?
2. How do the lifecycle stages of wild salmon populations make use of the habitat found in the vicinity of the proposed aquaculture development site?
3. What is the likelihood/probability of any impacts on the survivability and recoverability of the wild salmon populations found in the vicinity of the proposed aquaculture development site?
4. How can mitigation measures reduce any impacts on the wild salmon populations found in the vicinity of the proposed aquaculture development site? and
5. How do the impacts to the wild salmon populations from the proposed aquaculture development site compare to the impacts from other anthropogenic sources?

The Science Special Response Process (SSRP) was based on existing data sources from the Little Musquash Cove area, which are limited in resolution and scale relative to the location and size of the proposed aquaculture development site. An SSRP was used due to the short deadline for advice of January 15, 2011.  

The conclusions of the SSRP are:

1. A salmon aquaculture development at the proposed aquaculture development site has the potential to impact on salmon populations in three designatable units (DU): the inner Bay of Fundy (iBoF); the outer Bay of Fundy (oBoF); and the Southern Upland (SU) DUs. The IBoF DU is listed as Endangered under the Species at Risk Act (SARA) and the oBoF and SU DUs have been recommended for listing as Endangered by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The iBoF and oBoF DUs are known to be found in close proximity to the proposed site; whereas, although it is likely that SU salmon are at times present near the site (some populations are located in Nova Scotia directly across the Bay of Fundy), effects on SU salmon may occur via interactions with escaped salmon.
2. The general area around the proposed site at Little Musquash Cove is considered to be used as a migratory corridor and feeding grounds in support of growth, maturation, and post-spawning reconditioning.
3. Synthesis of available information indicates that at the beginning of the marine phase, iBoF salmon post-smolts tend to migrate along the New Brunswick side of the Bay of Fundy (the Bay), at least within 4-6 nautical miles of the site, and may circulate within the inner Bay.
4. Historically, adult salmon were captured in the area just offshore of the proposed Little Musquash Cove development site for extended periods during the late spring. Based on tag returns for Saint John River salmon, adults returning to spawn are present in the Bay of Fundy from at least May until November. They are also known to be present near the coastline and to move in and out of estuaries during this time period. Returning adults from at least the iBoF and oBoF DUs would be expected to pass nearby the proposed aquaculture site, and potentially more than one time.
5. Salmon aquaculture operations can impact wild populations through: the transmission of parasites, pathogens and disease from cage-farmed salmon; potentially increased predation as a result of predator attraction to the cage sites; and through an additional range of pathways that arise from aquaculture escapees. Escapees can return to freshwater, mature and reproduce with wild conspecifics. The resulting wild farm-wild hybrids have the potential to reduce fitness of wild populations through an increased risk of outbreeding depression. Salmon in the three DUs are at low abundance relative to past levels and are highly sensitive to increased stress and mortality.
6. A number of mitigation measures have been identified to reduce impacts from aquaculture activities on wild salmon populations, although the likelihood of risk reduction if these measures were implemented is unknown.
7. The relative severity of potential impacts from the proposed aquaculture development site relative to other anthropogenic sources cannot be determined.  However, these impacts have the potential to reduce the effectiveness of actions to improve the viability of salmon populations and to prevent their extirpation.  All commercial and recreational fisheries have been closed in the oBoF, iBoF and SU.  Live Gene Banking is currently being used to maintain the genetic diversity of iBoF salmon. Liming activities have been initiated in the SU DU. Fish passage improvements have been undertaken in all three regions. Activities that have the potential to jeopardize the survival of salmon in these regions need to be evaluated in the context of the activities that have been initiated to improve their survivability.

This Science Response report is from the Fisheries and Oceans Canada, Canadian Science Advisory Secretariat, Regional Science Special Response Process (SSRP) of December, 2010 on Potential Impacts to Wild Salmon Populations in the Vicinity of a Proposed Finfish Aquaculture Site at Little Musquash Cove, New Brunswick. 

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