Review of the Marine Harvest Atlantic Canada Inc. aquaculture siting baseline assessments for the south coast of Newfoundland

Abstract

The review of the 13 site applications for Atlantic Salmon aquaculture farms was conducted using the baseline assessments provided by the Proponent as required by the Aquaculture Activities Regulations (AAR), and other relevant scientific data, to evaluate the potential habitat and species interactions. Fisheries and Oceans Canada (DFO) is currently developing a consistent approach for the scientific evaluation of marine siting applications for finfish aquaculture. This review is the first implementation of this approach in the Newfoundland and Labrador (NL) Region. The Proponent used a depositional model (DEPOMOD) to predict the benthic carbon footprint of the proposed aquaculture sites. DFO Science used potential exposure zone (PEZ) calculations to provide an estimate of the spatial scale of PEZs but these do not quantify intensity or duration of exposure nor include a frequency of exposure. The two models provided similar results. There was an overlap between the mean benthic PEZ and the DEPOMOD outputs. Discussions related to approved drug and pesticide usages were limited to spatial considerations. Cumulative effects of biochemical oxygen demand, drugs, and pesticides were not discussed. Each of the sites was assessed for the presence of sensitive species, species listed under the Species at Risk Act, and sensitive habitats. At six of the sites, cold-water corals (e.g. sea pens), which are indicators of vulnerable marine ecosystems, were identified. At the Little Bay site, sea pens, which are known nurseries for redfish, were detected under the proposed cage array. The population-level effect of potential impacts was not assessed due to a lack of information available on the density and distribution of these species throughout the region. Sea lice pose a threat to the wild Atlantic Salmon populations. It is anticipated that the addition of sites will increase the presence of sea lice and, therefore, sea lice treatments. Assessments of wild Atlantic Salmon population status in the area are limited; however, existing counting fences indicate significant and consistent ongoing declines (approximately 80% over three generations), the cause of which is not fully understood. These populations are in the Critical Zone (below 100% conservation egg requirement). Moreover, existing data has documented the presence of escaped farmed salmon and hybridization between wild and farmed Atlantic Salmon throughout Salmon Fishing Area (SFA) 11. The assessment of the potential genetic impacts on Atlantic Salmon populations along the south coast of Newfoundland was completed based on the best available scientific data (North American and European) and the size and location of the existing and proposed sites. The proposed scale of expansion is predicted to result in an increased number of escapees in southern Newfoundland rivers largely in the Bay d’Espoir area compared to present operations. These increases are predicted to be associated with demographic decline and genetic change, though there is uncertainty as to the magnitude of both. Mitigation measures proposed by the Proponent to reduce the frequency of escape events were not included in the empirical predictions. These mitigation measures have been shown to be effective in other jurisdictions.