Globally, lobsters are one of the most economically valuable wild species caught in capture fisheries. Catches are dominated by American lobster (Homarus americanus) landed entirely in Atlantic Canada and northeastern United States. In Atlantic Canada, lobster fishing and marine finfish aquaculture take place in the same coastal waters creating the potential for negative environmental, as well as social, interactions. We review the state of knowledge of environmental interactions between American lobster, their habitat and fishery, and marine finfish aquaculture. We first provide a brief overview of key biological, behavioural, and ecological processes and environmental stressors of American lobster at different life-history stages followed by an overview of the pathways of effects of marine finfish aquaculture on coastal ecosystems in general and on American lobster. Our review found that certain finfish aquaculture-lobster interactions have received considerable study (e.g., chemical use), whereas knowledge of other interactions are either limited (e.g., net pens, waste discharges) or lacking (e.g., disease, noise, lights, and odours). An ecosystem-based approach to aquaculture has been proposed for managing these interactions but implementing this approach has proven to be a challenge in part because of complex multi-sector, multi-stakeholder and multi-agency governance issues. While governance solutions await development, practical measures based on the results of scientific research identified in this review, such as better use of existing oceanographic and bathymetric data, habitat and human impact assessment tools, and toxicity information offer regulators ample information and management tools, at least at the farm- and bayscale, to avoid negative finfish aquaculture-lobster interactions in Atlantic Canada. Bridging the governance gap will likely require new community-based management models that more effectively identify, generate, and integrate local community and fisher knowledge and concerns.

Canada is a signatory to United Nations conventions on sustainable development and has entrenched sustainability goals in legislation and policies relating to natural resource sectors including aquaculture. Monitoring and measuring progress towards sustainable development requires the development of sustainability indicators (SI) that, when measured, indicate movement towards or away from a stated policy objective, as well as providing the public with a measure of government accountability. This paper examined the SI used by the Canadian government to assess the social, economic and environmental sustainability of aquaculture production in Canada, whether they adequately measure policy outcomes, and whether national-level SI indicators are appropriate to assessing sustainability at the community-level. The analysis reveals that the Canadian government has made virtually no progress towards translating sustainable aquaculture policy aspirations into measurable SI that evaluate policy outcomes. The mismatch between national policy goals and on-the-ground consequences are highlighted in a community case study of finfish aquaculture in Port Mouton Bay (Nova Scotia). Aquaculture SI and sustainability narratives are discussed in relation to emergent governance arrangements (certification programs) and an international development initiative, Blue Growth, for the world's oceans.

Interactions between open-net pen finfish aquaculture and lobster catches in a sheltered bay in Nova Scotia, Canada, were investigated using fishermen's participatory research in annual lobster trap surveys over seven years. Fishermen recorded lobster catches during the last two weeks of May from 2007 to 2013. Catches for each trap haul were recorded separately for ovigerous and market-sized lobsters. Catch trends within the bay were compared to regional trends. Results of correlation analyses indicated that ovigerous catch trends were strongly affected by the fish farm's feeding/fallow periods. There was no significant correlation between trends for bay and LFA lobster landings. Patterns of lobster catch per unit effort extending over considerable distance in Port Mouton Bay appear to be influenced by proximity to the fish farm regardless of year-to-year variation in water temperatures and weather conditions. Odours and habitat changes surrounding open-net pen finfish operations are potential factors affecting lobster displacement.

Sediment and sea surface microlayer samples near an open-net salmon farm in Nova Scotia, were analysed for copper. Copper is a constituent of the feed and is an active ingredient of anti-foulants. The salmon farm was placed in fallow after 15 years of production. Sampling was pursued over 27 months. Elevated copper concentrations in the sediments indicated the farm site as a source. Bubble flotation due to gas-emitting sediments from eutrophication is a likely process for accumulating copper in the sea surface microlayer at enriched concentrations. Elevated and enriched concentrations in the sea surface microlayer over distance from the farm site led, as a result of wind-drift, to an enlarged farm footprint. The levels of copper in both sediments and sea surface microlayer exceeded guidelines for protection of marine life. Over the 27 months period, copper levels persisted in the sediments and decreased gradually in the sea surface microlayer.