Deep-water corals are significant ecosystem engineers that provide habitat complexity in the deep sea. They are indicator species of vulnerable marine ecosystems because of their slow growth and longevity, characteristics that can prolong recovery from disturbances such as fishing. For populations with discontinuous distributions, such as aggregations of deep-water corals, population connectivity is critical in regulating persistence and recovery and is one of the recommended elements in the design of area-based conservation measures. In this study, we assessed potential pathways of connectivity in the Corsair Canyon Conservation Area, off Nova Scotia, Canada, for populations of the deep-water corals Paragorgia arborea and Primnoa resedaeformis discovered in 2014 and afforded protection in 2016. Corsair Canyon located in the Canadian EEZ, ∼ 20 km from the border between Canada and the United States, is potentially receiving larvae from either the Canadian or US EEZ. In Corsair Canyon, P. arborea was very abundant at depths 484-856 m and some colonies of P. arborea were > 2 m high. These are the locally densest aggregations of P. arborea we have detected on the continental slope off Nova Scotia. We also recorded P. resedaeformis at similar depths. Colonies of both species were most often seen attached perpendicularly to a rock face, and into the current. We assessed hydrodynamic connectivity between Corsair Canyon and other canyons to the northeast and southwest along the continental slope with known occurrences of the two corals, using the ocean model Finite-Volume Community Ocean Model (University of Massachusetts-Dartmouth). Our results indicate that estimated hydrodynamic connectivity originates consistently from canyons to the southwest of Corsair Canyon, particularly Georges, and Heezen Canyons. Of these, only Georges Canyon is within Canada's EEZ and based on our data has very sparse populations of corals that can supply potential recruits. Predicted connectivity with the Northeast Channel Coral Conservation Area occurs in winter and spring, but the complexity of circulation in those seasons needs to be resolved to confirm the strength of this connection. Our results strongly suggest that cross-boundary coordination is essential in the conservation of aggregations of deep-water corals in the northwest Atlantic, by ensuring larval exchange and connectivity.

Deep-sea ecosystems provide services such as food, minerals, and nutrient recycling, yet baseline data on their structure is often lacking. Our limited knowledge of vulnerable deep-sea ecosystems presents a challenge for effective monitoring and mitigation of increasing anthropogenic threats, including destructive fishing and climate change. Using data from two stations differing in total epifaunal abundance and taxonomic composition, we compared the use of imagery collected by two non-invasive tools [remotely operated vehicle (ROV) and drop camera] and data collected with a trawl system, commonly used to quantify epibenthic megafauna in the deep sea. Imagery and trawl data captured different epifaunal patterns, the former being more efficient for capturing epifauna, particularly Pennatulacean recruits. The image-based methods also caused less disturbance, had higher position accuracy, and allow for analyses of spatial structure and species associations; fine-scale distributions could not be elucidated with a trawl. Abundance was greater for some taxa, and diversity accumulated faster with increasing sample size for the drop camera than the ROV at one station. However, there are trade-offs between these tools, including continuous and discrete sampling for the ROV and drop camera, respectively, which can affect follow-up analyses. Our results can be used to inform monitoring frameworks on the use of appropriate sampling tools. We recommend further research into tool sampling biases and biometric relationships to help integrate datasets collected with different tools.

In 2010 the Conference of the Parties (COP) for the Convention on Biological Diversity revised and updated a Strategic Plan for Biodiversity 2011–2020, which included the Aichi Biodiversity Targets. Here a group of early career researchers mentored by senior scientists, convened as part of the 4th World Conference on Marine Biodiversity, reflects on the accomplishments and shortfalls under four of the Aichi Targets considered highly relevant to marine conservation: target 6 (sustainable fisheries), 11 (protection measures), 15 (ecosystem restoration and resilience) and 19 (knowledge, science and technology). We conclude that although progress has been made towards the targets, these have not been fully achieved for the marine environment by the 2020 deadline. The progress made, however, lays the foundations for further work beyond 2020 to work towards the 2050 Vision for Biodiversity. We identify key priorities that must be addressed to better enable marine biodiversity conservation efforts moving forward.

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Deep-sea ecosystems are being impacted by anthropogenic stressors, such as trawling and oil-gas exploration. Protection of these ecosystems is delayed by limited understanding of spatial distribution, suitable habitat, species associations, and recruitment. Imagery was analyzed from the Laurentian Channel AOI and 3 canyons (Corsair, Georges, Fiddlers Cove) on the western Scotian Slope in the Northwest Atlantic Ocean. We used two sampling designs, exploratory linear transects and a systematic-cluster transect array and will compare the information that can be extracted from each method. Megaepifaunal biodiversity, abundance, and species-species associations were identified at each site. For example, at Fiddlers Cove, different types of Gorgonian corals (e.g. Acanella, Desmophyllum, and stoloniferous coral), soft corals, and sponges occurred mainly on outcrops; sea pens and anemones, along with large colonies of Paragorgia arborea were present in Corsair Canyon; and several Gorgonian corals, anemones, lobsters, and Holothuroidea were present in Georges Canyon. We will use spatial analyses to measure spatial structure at local and regional scales, identify species-environment associations, and predict suitable habitat for deep-sea megaepifauna. Overall, the study will provide a broader understanding of deep-sea megaepifaunal ecosystems, and develop recommendations for a deep-sea MPA monitoring framework to achieve effective conservation that promotes biodiversity.