Figure 10 - uploaded by Ellen L. Kenchington
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Maps for the 7 families of the order Gorgonacea present in the Maritimes Region. A-Distribution of unidentifiable families within the order Gorgonacea. BFamily Paragorgiidae which for our region currently contains two species: Paragorgia arborea and P. johnsoni. C-Family Plexauridae which includes at least one species of the large branching coral Paramuricea spp. D-Family Primnoidae represented by the species Primnoa resedaeformis.
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Over the last 6 years DFO research vessel fisheries surveys, in concert with benthic research missions focussing primarily upon recently established conservation areas (Northeast Channel (NEC) Coral Conservation Area (2002), the Stone Fence Lophelia Conservation Area (LCA) (2004) and the Gully Marine Protected Area (2004)), have dramatically increa...
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... . Of the 18 accepted species in the genus (Cordeiro et al., 2021), P. arborea (Linnaeus, 1758) and P. johnsoni Gray, 1862 are found on the continental slope off Nova Scotia, Canada, with P. arborea being the more frequently recorded (Cogswell et al., 2009;Strychar et al., 2011). In this region, both Paragorgia species are long-lived and slow-growing, attaining colony heights of 240 cm, and forming dense aggregations (Sherwood and Edinger, 2009;Watanabe et al., 2009). ...
... The two species of the genus found in the study area can co-occur (Cogswell et al., 2009), and can be difficult to identify in imagery. Of the 2377 presence records, 2124 were designated P. arborea, 11 were P. johnsoni, while the remainder could not be identified to species. ...
The large, habitat-forming bubblegum coral, Paragorgia arborea, is a vulnerable marine ecosystem indicator with an antitropical distribution. Dense aggregations of the species have been protected from bottom-contact fishing in the Scotian Shelf bioregion off Nova Scotia, Canada in the northwest Atlantic Ocean. Recently, basin-scale habitat suitability ensemble modeling has projected an alarming loss of 99% of suitable habitat for this species across the North Atlantic by 2100. Here, a regional reassessment of the predicted distribution of this species in the bioregion, using both machine learning (random forest) and generalized additive model (GAM) frameworks, including projection to 2046−2065, was undertaken. Extrapolation diagnostics were applied to determine the degree to which the models projected into novel covariate space (i.e., extrapolation) in order to avoid erroneous inferences. The best predictors of the species’ distribution were a suite of temporally-invariant terrain variables that identified suitable habitat along the upper continental slope. Additional predictors, projected to vary with future ocean climatologies, identified areas of the upper slope in the eastern portion of the study area that will remain within suitable ranges for P. arborea at least through to the mid-century. Additionally, 3-D Lagrangian particle tracking simulations indicated potential for both connectivity among known occurrence sites and existing protected areas, and for colonization of unsurveyed areas predicted to have suitable habitat, from locations of known occurrence. These results showed that extirpation of this iconic species from the Scotian Shelf bioregion is unlikely over the next decades. Potential climate refugia were identified and results presented in the context of protected area network design properties of representativity, connectivity, adequacy, viability and resilience.
... Previous studies of L. pertusa on the Scotian Shelf off Nova Scotia, Canada, were focused on describing this reef complex and its spatial extent (Buhl- Mortensen et al., 2017), on the design and implementation of the LCCA (Breeze and Fenton, 2007), or on the diversity of corals within its confines (Gordon and Kenchington, 2007;Cogswell et al., 2009). For the first time, we document the full epibenthic community (i.e., motile and non-motile primarily benthic fauna >1 cm) associated with the LCCA from in situ camera surveys conducted in three different years over a 12-year period. ...
... In March 2018, DFO proposed a conservation area (termed the Eastern Canyons Proposed Conservation Area) that would span from the Gully MPA in the west, across the eastern Scotian Slope to encompass the LCCA in the east. The purpose of this conservation area would be to protect significant concentrations of deep-water corals and sponges that are known to occur within and between the canyons that excise the area (Cogswell et al., 2009;Beazley et al., 2019). A possible extension of the boundaries of the LCCA are currently being considered as part of the design process. ...
In 2003, a large Lophelia pertusa reef complex was discovered on the southeast edge of the Scotian Shelf, representing the only known cold-water coral reef in Canada. Extensive damage to the reef from bottom fishing activities was apparent, which resulted in the establishment of the 15-km² Lophelia Coral Conservation Area (LCCA) in 2004 to prevent further damage and allow recovery. Since 2004, the effectiveness of the LCCA in achieving these objectives has never been assessed. Through the analysis of benthic images collected in 2003, 2009, and 2015, we evaluate the effectiveness of the LCCA in terms of its success in facilitating the recolonization and recovery of its target species, L. pertusa, and in conserving local benthic biodiversity. Using multivariate community analyses and generalized linear modelling techniques, we compare changes in the diversity, abundance, and composition of epibenthic megafauna within and outside its boundaries over the 12-year period. We observed an increase in epibenthic megafaunal species density and abundance over time that was higher inside the closure than outside, suggesting that the LCCA has facilitated the recruitment and recovery of the benthic communities within its confines. While recruitment of L. pertusa was low, the recent discovery of numerous undisturbed large mounds of live L. pertusa establishes a local recruitment source, a prerequisite for the reef structure to recover to its pre-disturbed state. We recommend that monitoring of the reef structure occur every 7-10 years to evaluate the settlement and growth of L. pertusa and the other deep-water corals that reside there.
... The thalweg meanders ≈50 km from the canyon head to the shelf break, where it is ≈2,000 m below the surface, and can be traced from there down the continental slope (for a detailed description, see Kenchington et al., 2014b). Certain components of The Gully's biota are notably enriched, including the cold-water corals, euphausiids, cetaceans, and some exploited fishes (Breeze, 2002;Sameoto et al., 2002;Cogswell et al., 2009;Whitehead, 2013). Early studies sought an explanation for that enrichment through local enhancement and retention of primary production (e.g., Kepkay et al., 2002;Mann, 2002). ...
Midwater trawl surveys were conducted during 2007–10 at meso- and bathypelagic depths in and near The Gully, a large submarine canyon off Nova Scotia that is also a Marine Protected Area. The fish assemblage in the canyon was highly diverse but 20 species together comprised more than 90% of the catch by number and 80% by weight. The most numerous was the gonostomatid Cyclothone microdon while the myctophid Benthosema glaciale was next in number and first in weight. Most of those principal species would be expected in catches taken in oceanic waters beyond the shelf break. Only the bottom-spawning Melanostigma atlanticum was, within the surveyed area, distinctively a species of the canyon. Multivariate analyses showed that the primary variations in the assemblage were aligned with drivers that act in open ocean: depth, water mass and both diel and seasonal cycles. However, the effect of the canyon was evident in an up-canyon decline in the catches of most species. We hypothesize that the oceanic species are passively carried into The Gully by the known inflow and are there exposed to intense predation, depleting their numbers. We estimate that biomass flux as sufficient to support the Marine Protected Area's signature species: northern bottlenose whales (Hyperoodon ampullatus).
... Mortensen and Buhl-Mortensen (2005a) report an observation of a possibly living colony from The Gully. There is also an observer report of L. pertusa in the Jordan Basin in the Gulf of Maine (Fig. 1), as well as a specimen deposited with the Nova Scotia Museum of Natural History reported to have been collected in one of the "holes" on Misaine Bank, around 160 km northwest of Stone Fence ( Fig. 1) (Cogswell et al., 2009). ...
... L. pertusa in Atlantic Canada may be regarded as scattered populations, similar to the isolated colonies seen at about 1000 m depth below the Stone Fence in 2007 (Cogswell et al., 2009), geographically isolated from other areas with more prolific populations. Similarly, along the margin of the northeastern US, the coral has only been observed as isolated small colonies, mainly in canyons (Brooke and Ross, 2014). ...
... In 2009, DFO revisited the reef area with CCGS Hudson and conducted some surveys using a platform with video and still cameras. Only a few occurrences of live Lophelia were documented so the status of the reef complex could not be assessed (Cogswell et al., 2009). The reef needs to be mapped in more detail and additional targeted video surveys should be performed to provide a baseline for monitoring. ...
For the first time, we describe a cold-water coral reef complex in Atlantic Canada, discovered at the shelf break, in the mouth of the Laurentian Channel. The study is based on underwater video and sidescan sonar. The reef complex covered an area of approximately 490 × 1300 m, at 280–400 m depth. It consisted of several small mounds (<3 m high) where the scleractinian Lophelia pertusa occurred as live colonies, dead blocks and skeletal rubble. On the mounds, a total of 67 live colonies occurred within 14 patches at 300–320 m depth. Most of these (67%) were small (< 20 cm high). Dead coral (rubble and blocks), dominated (88% of all coral observations). Extensive signs of damage by bottom-fishing gear were observed: broken and tilted coral colonies, over-turned boulders and lost fishing gear. Fisheries observer data indicated that the reef complex was subjected to heavy otter trawling annually between 1980 and 2000. In June 2004, a 15 km² conservation area excluding all bottom-fishing was established. Current bottom fisheries outside the closure include otter trawling for redfish and anchored longlines for halibut. Vessel monitoring system data indicate that the closure is generally respected by the fishing industry.
... The Scotian Shelf is characterized by a number of valleys, ridges, shallow banks, and deep basins that support a rich diversity of habitats and species, including several commercially-important fishes and invertebrates (Drinkwater et al., 2002). The Scotian Slope and the deep canyons that indent it support a high diversity of sensitive benthic invertebrates such as corals and sponges (Mortensen et al., 2006; Gordon and Kenchington, 2007; Cogswell et al., 2009). In 2014, Fisheries and Oceans Canada (DFO) identified eighteen Ecologically or Biologically Significant Areas (EBSAs) in the offshore component of the Scotian Shelf Biogeographic Region (DFO, 2014). ...
... Although our goal was not to identify the specific niche requirements of each coral and sponge group, ecological interpretation of the random forest models is necessary for determining the validity of the predictions and whether they are consistent with known information on distribution and biology. Corals were predicted to have the highest presence probability along the slope and in deep-water canyons, results that are consistent with the known distribution of these organisms (Breeze et al., 1997; Gordon and Kenchington, 2007; Cogswell et al., 2009). Depth and Slope were the top two predictors of the sea pen, and large and small gorgonian presenceabsence data. ...
... The Scotian Shelf is characterized by a number of valleys, ridges, shallow banks, and deep basins that support a rich diversity of habitats and species, including several commercially-important fishes and invertebrates (Drinkwater et al., 2002). The Scotian Slope and the deep canyons that indent it support a high diversity of sensitive benthic invertebrates such as corals and sponges (Mortensen et al., 2006;Gordon and Kenchington, 2007;Cogswell et al., 2009). In 2014, Fisheries and Oceans Canada (DFO) identified eighteen Ecologically or Biologically Significant Areas (EBSAs) in the offshore component of the Scotian Shelf Biogeographic Region (DFO, 2014). ...
... Although our goal was not to identify the specific niche requirements of each coral and sponge group, ecological interpretation of the random forest models is necessary for determining the validity of the predictions and whether they are consistent with known information on distribution and biology. Corals were predicted to have the highest presence probability along the slope and in deep-water canyons, results that are consistent with the known distribution of these organisms (Breeze et al., 1997;Gordon and Kenchington, 2007;Cogswell et al., 2009). Depth and Slope were the top two predictors of the sea pen, and large and small gorgonian presenceabsence data. ...
Effective fisheries and habitat management processes require knowledge of the distribution of areas of high ecological or biological significance. On the Scotian Shelf and Slope, a number of benthic ecologically or biologically significant areas consisting of habitat-forming species such as sponges and deep-water corals have been identified. However, knowledge of their spatial distribution is largely based on targeted surveys that are limited in their spatial extent. We used a species distribution modelling approach called random forest (RF) to predict the probability of occurrence and biomass of sponges, sea pens, and large and small gorgonian corals across the entire spatial extent of Fisheries and Oceans Canada’s (DFO) Maritimes Region. We also modelled the rare sponge Vazella pourtalesi, which forms the largest known aggregation of its kind on the Scotian Shelf. We utilized a number of data sources including DFO multispecies trawl catch data and in situ benthic imagery observations. Most models had excellent predictive capacity with cross-validated Area Under the Receiver Operating Characteristic Curve (AUC) values ranging from 0.760 to 0.977. Areas of suitable habitat were identified for each taxon and were contrasted against their known distribution and when applicable, the location of closure areas designated for their protection. Generalized additive models (GAMs) were developed to predict the biomass distribution of each taxonomic group and serve as a comparison to the RF models. The RF and GAM models provided comparable results, although GAMs provided superior predictions of biomass along the continental slope for some taxonomic groups. In the absence of data observations, the results of this study could be used to identify the potential distribution of sensitive benthic taxa for use in fisheries and habitat management applications. These results could also be used to refine significant concentrations of these taxa as identified through the kernel density analyses.
... These conditions promote high biological productivity and diversity, particularly in canyons and areas of intense upwelling or mixing (Freeland and Denman 1982;Hooker et al. 1999;De Leo et al. 2010;Moors-Murphy 2014). The slope is used as a migratory corridor and important habitat for many large pelagic fish, e.g., Swordfish (Tal Sperling et al. 2005) and Porbeagle Shark (Campana et al. 2002), cetaceans (Gomez-Salazar and Moors-Murphy 2014), and Leatherback Turtles (DFO 2011), provides a vertical migration route for mesopelagic species and larvae during diel feeding migrations, which can provide pulses of productivity to the rest of the slope ecosystem (Themelis 1996;Kenchington et al. 2014), and contains several sensitive ecosystems, such as coral communities and sponge aggregations Cogswell et al. 2009;Greenan et al. 2013;DFO 2014a). Certain ecologically significant and well-studied parts of the Scotian Slope EBSA have been identified as discrete EBSAs. ...
... One of these unique features is the The Gully, the largest submarine canyon off the east coast of North America. This feature has been studied extensively due to its significant diversity and abundance of deep-sea corals (Breeze et al. 1997;Hargrave et al. 2004;Cogswell et al. 2009;DFO 2014a), and its importance to an endangered population of Northern Bottlenose Whales (Moors-Murphy 2014). For these reasons, it was designated a marine protected area (MPA) in 2004 (DFO 2008). ...
... This area is called the Stone Fence. High current flow here limits the accumulation of sand, which can smother corals (Ramp et al. 1985;Cogswell et al. 2009;Edinger et al. 2011). At around 1000m depth, the Stone Fence is high slope environment characterized by eroded bedrock (Edinger et al. 2011). ...
Fisheries and Oceans Canada (DFO) Maritimes Region recently identified eighteen Ecologically and Biologically Significant Areas (EBSAs) within the offshore component of the Scotian Shelf Bioregion. These EBSAs were identified as areas that may require heightened management attention due to their biological or ecological importance. The Scotian Slope was identified as one broadly defined EBSA, because its steep slopes, unique geomorphology, and ocean current patterns support unique, diverse and productive ecosystems. The purpose of this report is to describe the variation in habitat types and ecosystems across the slope from east to west and with depth. This report adapts divisions of the Scotian Slope from a 2009 WWF-Canada report to describe the Scotian Slope and Rise in terms of geologically, oceanographically, and ecologically distinct “physiographic regions”. Furthermore, this report describes especially unique
natural features within these physiographic regions and how they may fit DFO EBSA criteria. It is recommended that marine management programs that utilize EBSA delineation and definition take note of the variation among physiographic regions considered here, and that DFO Maritimes evaluate the potential of additional special features identified here to be considered EBSAs.
... The increased exploitation of shellfish (Sherwood & Rose 2005) and deep-sea fish (Haedrich et al. 2001;Devine et al. 2006), has raised concerns about potential impacts on non-target benthic organisms (Koslow et al. 2000;Barrio Frojan et al. 2012). Recent research has focused on cold-water corals and sponges, owing to their function as biogenic habitat (Wareham & Edinger 2007;Cogswell et al. 2009;Baillon et al. 2012;Baker et al. 2012;Kenchington et al. 2013). Other non-commercial invertebrate groups that may be indicative of vulnerable marine habitats, such as echinoderms (Barrio Frojan et al. 2012), have received less attention. ...
... Of our regions, the LCNS had the lowest species diversity of asteroids and a dominance of C. crispatus, a species previously reported in high numbers in the Laurentian Channel (Nesis 1965;L evesque 2009). High abundances of pennatulaceans have also been reported in the Laurentian Channel (Cogswell et al. 2009;Baillon et al. 2014) but we did not confirm any association between pennatulaceans and C. crispatus there. Because we grouped all pennatulacean species together in the trawl analysis, their co-occurrence with C. crispatus may have been masked by stronger associations in other regions, such as those observed with pennatulaceans and soft corals at deeper depths. ...
Although continental shelf and slope environments typically exhibit high epifaunal biomass and have been subjected to increasing fishing pressure, ecological information on assemblages of non-commercial invertebrate species from subtidal and bathyal areas remains limited. Sea stars (Echinodermata: Asteroidea), which are known to influence communities through their feeding habits, have received less attention than structural taxa such as corals and sponges. To better understand the ecological roles of asteroids on continental shelves, we investigated ~30 species and assessed their distributions and co-occurrence with other benthic invertebrates on the shelf and slope of Eastern Canada. Using fisheries data and in situ video footage, we compiled a large dataset covering ~600,000 km2 that included over 350,000 individual asteroid records (37–2243 m depth). Multivariate analyses revealed geographically distinct asteroid assemblages, with a maximal overall density at 400–500 m and the highest diversity at 500–700 m. The most abundant and densely occurring species was Ctenodiscus crispatus. We found that asteroids associate with corals, sponges, bivalves, and other echinoderms, and that depth and substrate influence these assemblages. We identified species likely to affect coexisting organisms by their burrowing behavior that can disrupt epi- and infauna (C. crispatus) and through predation on ecologically important corals (Hippasteria phrygiana). In addition to providing baseline distribution and ecological information for many bathyal asteroid species in the Northwest Atlantic, this work highlights the abundance and diversified roles of asteroids within continental shelf and slope ecosystems.
... The Gully is characterized by a diversity of habitats and marine life. It has the highest known diversity of corals in Atlantic Canada (Cogswell et al., 2009), has a relatively high diversity of bathyl epibenthic megafauna and dermersal finfish, may be important spawning grounds for some marine fish (Zwanenburg, 1998), and has greater overall biomass, abundance and diversity of larger pelagic crustaceans, including numerous rare species not previously observed in Canadian waters, than adjacent slope waters . The Gully is also known for a high diversity and abundance of cetaceans and it has been suggested that this may be one of the most important cetacean habitats on the Scotian Shelf (Whitehead et al., 1998). ...
... Research in smaller areas can also be used to confirm or identify important areas for certain species or taxa. This approach has been used to map known concentrations of certain coldwater coral species (e.g., Cogswell et al. 2009) and key habitats for endangered whale species (e.g., Whitehead 2013). ...
... The SEO EBSA workshop highlighted unique areas on the shelf, including the Rock Garden, a bedrock outcrop that supports a unique benthic community in the Gulf of Maine (Doherty and Horsman 2007). Additional examples of unique features in the bioregion include: the Gully (largest submarine canyon on the east coast of North America), the Stone Fence Lophelia pertusa reef (only known example in the Northwest Atlantic) (Cogswell et al. 2009), and the Emerald Basin Russian Hat sponge communities (possibly globally unique concentrations). The recommended approach for identifying unique and rare habitats in the offshore is to re-evaluate, confirm and refine (if necessary) each of the EBSAs identified in the SEO (Doherty and Horsman 2007) and LEK (Maclean et al. 2009) exercises. ...
... Structure providing corals and aggregating sponges represent potential ESS in the bioregion. Available spatial cold-water coral and sponge data from DFO RV surveys, the Fisheries Observer Program (FOP), LEK studies and a growing list of Remotely Operated Vehicle (ROV) surveys have been compiled into a Maritimes Region Coral Database (Cogswell et al. 2009). These data were used to create general distribution maps for each of the five coral orders that occur in the region (Alcyonacea, Antipatharia, Gorgonacea, Pennatulacea, and Scleractinia) (Cogswell et al. 2009). ...
Building on the preliminary Marine Protected Area (MPA) network analysis completed by Horsman et al. (2011), Fisheries and Oceans Canada (DFO) is leading a systematic approach to MPA network planning in the Scotian Shelf Bioregion. The major steps in the planning process are described in the National Framework for Canada’s Network of MPAs (Government of Canada 2011). Guidance from the Convention on Biological Diversity (CBD 2009a; COP 9 Decision IX/20, Annexes I-III) will also be carefully considered. Early steps in the planning process include setting clear conservation objectives, compiling habitat classification and Ecologically and Biologically Significant Areas (EBSAs) data, and analyzing these data to identify a set of areas that would collectively satisfy the conservation objectives of the network. This research document offers a review of the habitat classification and EBSA data layers used in Horsman et al. (2011) and identifies additional data sources to be considered in the next iteration of the MPA network analysis for the offshore component of the bioregion. The Kostylev and Hannah (2007) classifications (Scope for Growth and Natural Disturbance) and the Fader1 classification (Seabed Feature) are recommended to be used as a basis for evaluating habitat representation in designing the MPA network. A data-driven approach similar to that used by Horsman et al. (2011) is recommended for the identification or refinement of offshore EBSAs. Reliable data under each of the CBD EBSA criteria should be compiled and ultimately incorporated into the next iteration of the network design analysis. It is also recommended that the Scientific Expert Opinion (SEO) and Local Ecological Knowledge (LEK) EBSAs (Doherty and Horsman 2007, Maclean et al. 2009) be re-evaluated against the CBD EBSA criteria to ensure that known significant areas are not missed in the data-driven approach.
