Science Advisory Report 2019/025

Assessment of the Effectiveness of Mitigation Measures in Reducing the Potential Impacts of Oil and Gas Exploration and Production on Areas with Defined Benthic Conservation Objectives

Summary

• The focus of this review was on the potential effects of oil and gas exploration and production activities, and their mitigation, in the context of potential impacts to benthic species, features and habitats (including habitat functionality) in areas with defined benthic conservation objectives.
• Accidental events (i.e., spills and blowouts) were beyond the scope of this review, which focuses on planned routine activities and discharges associated with offshore exploration and production.
• Areas with benthic conservation objectives are those where a higher vulnerability to anthropogenic activities is often inferred, or where vulnerability has been explicitly identified. Therefore, a lower threshold of impact and a higher expectation of mitigation may be more appropriate for them.
• Based on the above, oil and gas exploration and production activities within habitats with defined benthic conservation objectives should be managed with higher risk aversion than activities in areas without these habitats. Beyond the placement of infrastructure to prevent direct destruction of individuals and/or individual colonies of species in areas with defined benthic conservation objectives, current management practices do not distinguish between areas with and without defined benthic conservation objectives in terms of the habitat-scale features and processes that they support.
• Aside from the benthic species, features or habitat(s) that may be directly affected by oil and gas exploration and production activities, there is also a need to understand what the potential impacts could be at the community level (e.g., food web and ecological linkages) as well as the cumulative impacts within areas with benthic conservation objectives. Impacts to benthic species, features or habitats may also have consequences for pelagic species that depend on them directly or indirectly. The benthic conservation objectives associated with each area will point to what level of consideration is needed (e.g., habitat, ecosystem structure and function, features, etc.).
• The activities of oil and gas exploration, development, and production are likely to overlap with areas with defined benthic conservation objectives. The significance of those impacts should be determined on a case-by-case basis to account for site-specific ecology and environmental conditions.
• Seismic surveys typically occur across a large geographic scale; therefore, seismic surveys may result in similar impacts between sites and across a larger geographic area in comparison with drill based exploration or production which have a smaller geographic footprint, and their impacts may be more variable and site-specific.
• The suite of activities, as well as their spatial and temporal footprint, varies significantly between oil and gas exploration and development operations. Exploration operations include seismic activities (usually over a larger geographic scale), along with a very short period of exploratory drilling (short duration – usually single well). Development and production operations, which can include drilling, tend to be more geographically focused but can extend for tens of years. Therefore, potential impacts and mitigations to oil and gas operations phases will also vary.     
• Mitigation measures are ideally identified and implemented in accordance with the widely-accepted "mitigation hierarchy" of: (1) avoid; (2) mitigate; and (3) offset (recognizing that offsetting will not generally be compatible with benthic conservation objectives). The optimal mitigation measure avoids the impact entirely by eliminating the possibility of interaction between the activity and the area with the defined benthic conservation objective, thereby removing all potential pathways of effects.
• The research available for the effectiveness of mitigation measures in areas with defined benthic conservation objectives was not sufficient to provide prioritized recommendations regarding which mitigation(s) would be most effective. A case-by-case approach to development of mitigation recommendations is considered the preferred approach at this time.
• Standardization of the description and definitions relating to areas with defined benthic conservation objectives would be helpful within and across agencies.
• While a national review, most of the examples available were from the Atlantic Coast  ̶  Arctic offshore would require further review.

This Science Advisory Report is from the June 26-28, 2018, held in St. John's, NL, entitled "Assessment of the Effectiveness of Mitigation Measures in Reducing the Potential Impacts of Oil and Gas Exploration and Production on Areas with Defined Benthic Conservation Objectives. Additional publications from this meeting will be posted on the Fisheries and Oceans Canada (DFO) Science Advisory Schedule as they become available.

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