Science Advisory Report 2014/041
Offshore Ecologically and Biologically Significant Areas in the Scotian Shelf Bioregion
- Eighteen Ecologically and Biologically Significant Areas (EBSAs) were described and delineated in the offshore component of the Scotian Shelf Bioregion. Seventeen of the EBSAs occur on the Scotian Shelf or Scotian Slope and one EBSA was identified in the deeper waters beyond the slope.
- The approach used to refine the list of EBSAs consisted of an evaluation of the Scientific Expert Opinion EBSAs based on available broad-scale ecological and biological data and a review of the literature. Notable ecological and biological features under the different DFO EBSA criteria were highlighted for each EBSA.
- One-hundred and forty-nine ecological or biological data layers were compiled or created to help evaluate and identify EBSAs in the offshore component of the Scotian Shelf Bioregion. The data layers were organized under the themes of: areas of high biological productivity or biomass, areas of high fish and invertebrate diversity, important habitats for fishes and invertebrates, coral and sponge occurrences, Critical Habitat for species at risk, important areas for seabird functional guilds, and distinct physical conditions.
- Specifically, the following data layers were presented:
- Areas of persistent, relatively high chlorophyll concentrations (as an index of phytoplankton biomass) in the Scotian Shelf Bioregion using satellite-derived MODIS ocean colour data from the National Aeronautics and Space Administration.
- Areas of high fish and invertebrate biomass on the Scotian Shelf using the DFO summer Research Vessel (RV) data.
- Three species diversity indices, Species Richness, Heip’s Evenness Index and the exponential of Shannon-Weiner Index, for fishes and invertebrates using the DFO RV data.
- Important habitat layers for a suite of fish species using summer, spring and fall DFO RV survey data.
- Coral and sponge occurrences using data from the Maritimes Region Coral Database.
- Critical Habitat for the Endangered North Atlantic Right Whale and Northern Bottlenose Whale.
- Areas of high relative abundance for eight seabird functional guilds using data from Environment Canada.
- Distinct physical conditions based on previous research to identify areas with different scope for growth and natural disturbance regimes.
- A more systematic, data-driven approach could have been applied; however, such a method would have produced results that were skewed toward highly sampled components of the bioregional ecosystem (i.e., demersal fishes). The approach that was employed made use of available broad-scale data while also considering smaller scale, site-specific research findings and expert knowledge.
- Where appropriate, EBSA boundaries were aligned with recognized physical, ecological or biological features, such as the underlying bathymetry.
- Significant gaps exist in the available ecological and biological data for the Scotian Shelf Bioregion. For instance, less information is available for the slope and deeper-water environments than the shelf; demersal environments are generally better-studied than the pelagic and mesopelagic realms; and synoptic distribution information is not available for certain taxonomic groups (e.g., cetaceans, sharks, tunas, sponges).
- Further investigation is required to refine several of the larger EBSAs, such as the Scotian Slope, Laurentian Channel, and Georges Bank. Other available survey data should be analyzed to identify the most ecologically and biologically significant locations within these broadly defined EBSAs. Discrete physical features (e.g., submarine canyons) should also be delineated and described within these EBSAs.
- The DFO RV data were used to create many of the data layers considered in this analysis so it is important to acknowledge the limitations of these surveys. For example, certain parts of the shelf are not sampled due to untrawlable bottom types. The seasonal coverage of the RV data is also limited, and the RV survey gear does not capture all species equally.
- The initial analysis to identify areas of persistent, relatively high chlorophyll concentrations in the Bioregion should be refined by splitting the shelf waters into eastern and western components due to the differences in the oceanographic environments of these areas. Separate seasonal layers should also be developed to account for the significant variability in chlorophyll concentrations throughout the year.
- Additional analysis is required to further characterize the spatial and temporal patterns in biodiversity in the Bioregion. To fully contribute meaningful scientific advice about the biodiversity on the Scotian Shelf, functional trait diversity, such as diversity of trophic guilds, size structure and other metrics must be explored in addition to extending the suite of species included in the diversity analysis presented here. Where sufficient relative distribution information does not exist, habitat modelling approaches can be explored to predict where the most important habitats are for certain species.
- The EBSAs and the individual EBSA data layers presented in this report will be considered in a broad range of coastal and oceans management and planning processes in the Scotian Shelf Bioregion, including environmental assessments, environmental emergency response, sustainable fisheries policies and Marine Protected Area network planning. Each EBSA will undergo an evaluation to identify potential management needs.
This Science Advisory Report (SAR) is from the February 18-20, and March 24, 2014 Updating Offshore Ecologically and Biologically Significant Areas in the Scotian Shelf Bioregion. 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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