WEBMR Monitoring Review

Western and Emerald Banks Marine Refuge (WEBMR) lies on the eastern Scotian Shelf, encompassing an area of over 10,234 km2, across depths that range from 37 to 211 m. Since time immemorial, the waters of the Scotian Shelf, which include the WEBMR, have provided natural resources and sustenance for the Mi’kmaq who have longstanding traditional and cultural connections to the marine environment and species. Ecological Features Key ecological features of the site have been described previously, reflecting its role as an Ecologically and Biologically Significant Area, including: large areas of sand/gravel bank habitat, representing important spawning and nursery areas for a variety of groundfish and Atlantic Herring; a partial gyre, which results in retention of pelagic larvae and their food; high larval fish diversity and benthic habitat heterogeneity relative to other areas on the Scotian Shelf; and high invertebrate diversity, including structure-forming species such as sea pens, glass sponges and horse mussels, which serve as habitat for juvenile fish. While marine mammals are not identified as a conservation priority for this marine refuge, WEBMR occurs within the known distribution range of numerous cetacean species, including blue, fin, sei, minke, humpback, and North Atlantic right whales, as well as sperm and pilot whales, Harbour Porpoise, and a variety of dolphin species. The topography and geology of the site are not expected to change significantly over time; however, its oceanographic conditions, such as temperature, pH, oxygen, and nutrients are shifting as a result of climate change, which, in turn, are expected to influence its biological communities. For example, temperatures within WEBMR have shown a warming trend since 2005, with declines in both Calanus finmarchicus abundance and overall zooplankton biomass, which is consistent with the overall trend observed across the Scotian Shelf. Monitoring Indicators A suite of indicators to support monitoring of WEBMR are proposed, building on work conducted regionally and nationally on Oceans Act Marine Protected Areas (MPAs), other effective conservation measures, and conservation networks more generally, along with consideration of WEBMR’s unique ecological features and conservation history. Proposed indicators include contextual indicators, which measure oceanographic and biological conditions; effectiveness indicators related to WEBMR’s three conservation objectives; and indicators to measure pressures and impacts of anthropogenic activities. Monitoring Platforms A number of scientific data collection programs are in place that can and have contributed towards the long-term monitoring of WEBMR. The DFO Maritimes Summer Ecosystem Research Vessel Survey (RV Survey), conducted annually since 1970, follows a stratified random sampling design and includes bottom otter trawl sampling of fish and invertebrates, oceanographic sampling, as well as collection of acoustic data, which can be used to support population analysis of small pelagic fish species like Atlantic Herring and Mackerel as well as Pollock. The RV Survey has conducted an average of 17.5 stations per year inside WEBMR since 2020, representing an important source of information on fish diversity, abundance, and productivity. Invertebrate catch data from the RV Survey has been reported annually since 2007, when identification protocols were enhanced. It was improved again in 2017, when a more detailed sampling protocol was established, forming a basis for the delineation of WEBMR’s benthic communities. Combining RV Survey data with environmental DNA (eDNA) sampling has the potential to enhance biodiversity monitoring, with eDNA providing additional species detections not captured by the RV Survey alone. Results to date have highlighted eDNA metabarcoding’s capacity to detect taxa that are otherwise missed by traditional sampling methods. The Atlantic Zone Monitoring Program (AZMP) samples a broad suite of physical, chemical, and lower trophic-level biological parameters at two stations (HL4 and HL5 of the ‘Halifax Line) within WEBMR during its spring and fall surveys, and evaluates satellite-derived measurements of sea surface temperature and ocean colour, representing an important source of oceanographic information on long-term ecosystem changes. Since 2018, AZMP has incorporated the use of ocean gliders into its monitoring program. Approximately 10 glider missions per year are conducted along the program’s Halifax Line, which intersects WEBMR. These glider missions provide high spatial resolution observations on a suite of physical (e.g., temperature, salinity) and biogeochemical (e.g., chlorophyll fluorescence, oxygen) properties, that can help resolve meso- and sub-meso scale processes and boundary currents. Like ocean glider and satellite-derived datasets, high resolution oceanographic models are important tools that can be used to fill spatial and temporal gaps in observational data. The spatial continuity and forecasting capacity of some models makes them useful tools for evaluating species distributions and assessing change in relation to climate change. Other data collection programs and approaches, such as the industry/DFO halibut longline survey, acoustic telemetry, passive acoustics, and targeted benthic missions to collect benthic imagery and samples (e.g., using Campod or Videograb), have all been deployed within WEBMR, representing other potential sources of ecological information to monitor biological communities, and their associated habitats, over time. Reporting Framework A hierarchical reporting framework for conservation monitoring is proposed, in which ecosystem indicators for specific conservation areas, like WEBMR, are integrated into regional conservation network reporting, and more broadly into shelf-wide, ecosystem based reporting. Consistent with the application of a holistic, ecosystem approach in the Maritimes Region, this framework proposes alignment of indicators with productivity, biodiversity, and habitat objectives, emphasizing the role that conservation areas can play in maintaining ecosystem structure and function, species diversity, ecosystem resilience, and the protection or restoration of habitat. In addition to a monitoring framework, an analytical oceanographic modelling framework could be used to support interpretation of site-specific oceanographic indicators in the broader regional context and facilitate understanding of the trends and status of the indicators that are selected. Knowledge Gaps There is currently no systematic, routine monitoring program that targets ichthyoplankton or benthic communities in the Maritimes Region. While benthic species are recorded in the annual RV Survey, additional laboratory examination is often required to identify sponges, hydroids, and sea anemones to the species level. Given the importance of WEBMR as historical spawning and nursery grounds for groundfish, and its objectives to protect benthic habitats that support Haddock and other groundfish species, a means of monitoring ichthyoplankton abundance at a regional scale, as well as benthic communities within WEBMR, would be highly beneficial for monitoring the effectiveness of WEBMR. In the distant past, some areas within WEBMR would have been above sea-level and could have been occupied by early Mi'kmaw peoples, representing an opportunity for future archeological investigation.