Science Advisory Report 2024/063

Newfoundland and Labrador Region Science Review of Six Proposed Finfish Aquaculture Sites on the South Coast of Newfoundland

Summary

• MOWI Canada East Incorporated submitted applications to the Province of Newfoundland and Labrador to develop and operate six new finfish aquaculture sites for Atlantic Salmon on the south coast of Newfoundland split among three fjords within two proposed aquaculture management areas, Bay de Vieux and Aviron/La Hune Bays.
• Estimates of benthic-Potential Exposure Zone (PEZ) for feed waste for each site showed no overlap. Estimates of benthic-PEZ for feces overlapped at adjacent sites within the same bay. Feed waste and feces can potentially contain bound substances such as medications.
• Pelagic-PEZ, which estimates the spatial extent across which exposure to registered pesticides may result in adverse effects, overlaps between sites within the same aquaculture management areas. These pelagic-PEZs extend to water masses beyond the bays and reach shorelines which may impact the shallow areas adjacent to each site.
• Chemotherapeutant sea lice treatments could affect non-target crustaceans through the exposure of adults in the benthos to in-feed residues, and/or their larval stages through pelagic exposure to pesticides. For primarily pelagic krill species, pesticide exposure might represent a risk at most sites.
• Treatments that occur at adjacent sites may result in cumulative impacts at sites where benthic and pelagic-PEZs overlap. For the Foots Cove and Shoal Cove sites, high densities of crustaceans that are in close proximity to cage areas might be at a higher risk.
• Soft corals and sea pens were identified at five of the sites. At Gnat Island, the sea pen Pennatula aculeata was detected in high concentrations adjacent to the proposed cage array. Lack of data on the density, distribution, and effects on these species and habitats in the surrounding area limit understanding of the potential impacts.
• There are 55 Atlantic Salmon rivers along the southwest coast of Newfoundland. Monitoring data from recent decades suggests that all three monitored rivers in the region have shown evidence of multi-generational population declines, with Bay d’Espoir showing declines exceeding 90%.
• Widespread hybridization between wild salmon and aquaculture escapees, and resulting genetic changes, have been documented in southern Newfoundland over the past decade. The continued observations of European ancestry in escaped farmed salmon in Atlantic Canada increases the direct genetic risk to wild populations.
• Empirical data and dispersal modeling analyses showed that for Designatable Unit 4b, the area of the proposed expansion, the number of escapees in the rivers is predicted to increase by 10% under the proposed expansion, with most occurring in White Bear River and Grey River. Ongoing impacts are predicted on both the abundance and genetic character of wild salmon in the region, and the risk of impacts is predicted to increase under the proposed expansion.
• An increase in aquaculture infrastructure increases the potential for entanglement for some Species at Risk. These include White Shark, Blue Whale, Fin Whale, North Atlantic Right Whale, and Leatherback Sea Turtles which occur in the general area, particularly from spring to autumn. Nonetheless, there are no reports of entanglement of these species in finfish aquaculture gear in the Newfoundland and Labrador Region.
• Two benthic fecal-PEZs (Denny Island, Gnat Island) minimally overlap (<1 km²) the current South Coast Ecologically and Biologically Significant Area (EBSA). Benthic waste feed-PEZs do not overlap this EBSA.
• The Canadian Science Advisory Secretariat (CSAS) review process for aquaculture siting would greatly benefit from a framework process that refines guidelines for science input.

This Science Advisory Report is from the April 23–26, 2024 regional peer review process for Aquaculture Siting Advice for Provincial Site Licence Applications from MOWI Canada East Incorporated.

Science Advisory Report 2024/063 (PDF, 3,114 KB)

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