Interaction between sperm whales (Physeter macrocephalus) and northern bottlenose whales (Hyperoodon ampullatus) and deep-water trawlers in the Northwest Atlantic

Interactions between various cetacean species and fisheries are geographically widespread and diverse. Foraging in association with fishing activities may increase prey encounter rates and possibly increase the quantity and the quality of the food consumed. This paper describes interactions between benthic trawlers, targeting mainly Greenland halibut, and two whale species: sperm whales and northern bottlenose whales, in the eastern Grand Banks of the northwest Atlantic. Whale behaviors were compared during four trawling-related activities: preparing/ shooting the net, towing, hauling and transiting between fishing sites. Sperm whales and bottlenose whales were more likely to be observed during hauling. We observed probable feeding behavior of both species close to the surface at the end of hauling which suggests they are taking fish escaping from the cod end of the net when it is close to the surface. It is not clear whether feeding attempts are made during other phases of the trawling cycle. Ten sperm whales were photo-identified and six of these individuals were resighted on different days. Resights of individuals indicated that sperm whales could follow trawlers through several sets over of distances up to 234 km. While some individuals were observed to move between fishing grounds others remained within one fishing area for some time. By contrast, even though twenty-three bottlenose whales were photo-identified, there were no resights of individual whales. While northern bottlenose whales have been studied quite extensively in some adjacent areas, particularly off Nova Scotia, their behaviour and distribution within the Grand Banks fishing areas has not been well described. No matches were found between northern bottlenose whales in this study and photo-identification catalogues for the Scotian Shelf or the Arctic. Whether and how northern bottlenose whales found in this area are connected to other subpopulations remains unclear.

Development of Iceberg Profiling Technology

Iceberg management on the Grand Banks of Newfoundland, Canada is currently carried out without knowledge of the underwater shape of the iceberg. An iceberg profiling system is being developed to integrate the rapid generation of 3D iceberg shape data with a collection of tools that utilize the data to provide recommendations, intended to improve iceberg management effectiveness. The intent is for the system to be operated by vessel crew with minimal training. The system utilizes a LiDAR and a pole mounted multibeam sonar to profile the iceberg sail and keel, respectively. A vessel equipped with the profiling system circles an iceberg twice to collect a profile, a process that on average requires approximately 15–30 minutes. The data is collected in the form of a point cloud, which must be de-noised and corrected for both drift and rotation of the iceberg. Tools have been developed to assess the stability of the iceberg, and to consider the shape of the iceberg relative to towing net dimensions, to provide guidance to the operator regarding the recommended towing direction to avoid iceberg rolling or net slippage events. Other applications of the profile data include an impact loads analysis tool that determines the distribution of potential iceberg loads in the event of a collision with a given platform, and an operational iceberg drift model that uses the iceberg shape to improve iceberg drift forecasts. Large-scale field programs were carried out in both 2018 and 2019 as part of the development process for the system. Data collected has shown that iceberg characteristics have changed significantly when compared to iceberg profile data collected in the 1980s. For a given iceberg waterline length, the more recent data shows significantly reduced drafts. The 1980s iceberg dataset currently dominates the data used as the basis for assessing iceberg loads on surface facilities and iceberg risk to subsea assets. Reduced iceberg drafts will result in reduced risk to subsea facilities and pipelines. These results and observations demonstrate the usefulness of the iceberg profiling system as an environmental monitoring tool, and the data collected has design and operational applications. The development and capabilities of the system are presented, as well as the comparison of the 1980’s and newer iceberg datasets and implications for iceberg risk to facilities on the Grand Banks and surrounding regions.

The (un)sustainable game: An exploration of rhetorical strategies and risk communication in sustainable seafood campaigns

In the 1990s, following the Newfoundland Grand Banks cod fishery collapse along Canada’s East Coast, the first seafood sustainability certification organization was formed to address this widespread crisis. Two notable campaigns were formed shortly thereafter, both programs the projects of marine aquariums along the West Coast, and have gained significant attention: Vancouver Aquarium’s Oceanwise provides seafood recommendations to restaurants on the most sustainable choices and Monterey Bay Aquarium’s Seafood Watch, creates and disseminates consumer guides. This MRP examines the communication strategies of Seafood Watch and Ocean Wise used to encourage the consumption of sustainable seafood and promote ocean conservation. More specifically, this MRP analyzes the organizations’ use of environmental rhetoric, particularly in terms of framing and topoi, and how they communicate risk and urgency. How sustainable seafood campaigns establish credibility and rationale in the public sphere to communicate urgent, technical information surrounding fishery mismanagement is examined. This research will help inform future guidelines for social marketing campaigns to improve strategy and encourage consumer change. Recommendations for future research include the creation of evaluative programs to measure campaign effectiveness as well as an analysis of the niche markets established through the rising sustainable seafood market.

The (un)sustainable game: An exploration of rhetorical strategies and risk communication in sustainable seafood campaigns

In the 1990s, following the Newfoundland Grand Banks cod fishery collapse along Canada’s East Coast, the first seafood sustainability certification organization was formed to address this widespread crisis. Two notable campaigns were formed shortly thereafter, both programs the projects of marine aquariums along the West Coast, and have gained significant attention: Vancouver Aquarium’s Oceanwise provides seafood recommendations to restaurants on the most sustainable choices and Monterey Bay Aquarium’s Seafood Watch, creates and disseminates consumer guides. This MRP examines the communication strategies of Seafood Watch and Ocean Wise used to encourage the consumption of sustainable seafood and promote ocean conservation. More specifically, this MRP analyzes the organizations’ use of environmental rhetoric, particularly in terms of framing and topoi, and how they communicate risk and urgency. How sustainable seafood campaigns establish credibility and rationale in the public sphere to communicate urgent, technical information surrounding fishery mismanagement is examined. This research will help inform future guidelines for social marketing campaigns to improve strategy and encourage consumer change. Recommendations for future research include the creation of evaluative programs to measure campaign effectiveness as well as an analysis of the niche markets established through the rising sustainable seafood market.

Changes in the Gulf Stream preceded rapid warming of the Northwest Atlantic Shelf

The Northwest Atlantic Shelf provides ecological and economic benefits along the heavily populated North American coastline and beyond. In 2009-2010, abrupt warming prompted an ecosystem shift with consequences for fisheries, yet the cause of this event is unclear. Here we use satellite altimetry and in situ measurements to show that, in 2008, the Gulf Stream migrated closer to the Tail of the Grand Banks, a shift that has persisted ever since. This change reduced the westward connectivity of the Labrador Current that otherwise supplies cold, fresh, oxygen-rich waters to the shelf. Within one year after the appearance of anomalously warm and saline water at the Tail of Grand Banks, subsurface warming progressed south-westwards. Historical observations suggest a similar sequence of events may have occurred in the 1970s. Therefore, monitoring water properties at the Tail of Grand Banks may offer predictability for shelf properties and ecosystem perturbations with substantial lead time.

Interaction of a Glacial Water Outflow with the Gulf Stream

<p>A popular hypothesis in paleoclimatology posits that the episodic discharges of glacial water from the Laurentide Ice Sheet (LIS) to the North Atlantic caused abrupt changes in ocean circulation and climate during the last (de)glacial periods. Implicit in this hypothesis is that the glacial water spread away from the coast and reached critical sites of deep water formation. Among the processes that could favour the offshore export of glacial water released along the eastern North American coast is the entrainment with the Gulf Stream near Cape Hatteras, where the Stream is observed to detach from the coast in the modern climate, or at other locations between Cape Hatteras and the Grand Banks of Newfoundland.</p><p>Here we investigate the fate of glacial water released in the western North Atlantic from the Laurentian Channel, which geologic evidence suggests to have been the main route of ice discharge from the Québec-Labrador Ice Dome of the LIS. To this end, we conduct numerical experiments with an ocean circulation model with eddy-resolving resolution and configured to represent the region north of Bermuda and west of the Grand Banks. Experiments with different regional sea levels are performed which correspond to different estimates of global sea level since the Last Glacial Maximum. In each experiment, glacial water in liquid form is discharged from the Laurentian Channel, providing a paleoceanographic analogue of the dam-break problem. As expected from the action of the Coriolis force and from the properties of the glacial water inflow, the discharged water turns to the right of the Channel and then produces a narrow buoyant current that flows along the coast to the southwest towards Cape Hatteras. Our presentation will focus on the interaction of this current with the Gulf Stream, particularly with its meanders and rings, and on the role of this interaction both in the seaward export of glacial water and in the modification of the Stream itself.</p>

Investigating the internal lithological structure and rock magnetic signature of Heinrich Event layers at SE Grand Banks Slope, Newfoundland

<p>Periodic mass discharges of icebergs from the Laurentide ice-sheet into the North Atlantic Ocean during the last glacial period deposited abundant ice-rafted detritus (IRD) accumulated in sequences of typically six major Heinrich Event layers, each with some tens of cm thickness, at all eastern slopes of the Grand Banks submarine platform of Newfoundland. Compositionally, it is well established that these IRD layers consist of varied rock contents emanating from distinct, but not yet clearly defined bedrock provinces of the Canadian Shield. The, most prominently reported constituent is detrital dolomite, but the entire lithological range of the IRD is much broader. Rock magnetic records, e.g. magnetic susceptibility logs of SE Grand Banks cores, therefore depict complex and partly repeating internal substructures across the Heinrich Event layers owing to distinct successions in IRD lithology over the course of every mass calving event.</p><p>We investigated IRD sieve fractions (1mm – 4cm) of the entire glacial section (550–1054 cm) of SE Grand Banks slope gravity core GeoB 18530-1, sampled in 2.3 cm steps. Therefrom, we identified and classified distinct IRD rock types as well as monocrystalline rock-forming mineral particles, for which we established so far 24 well-defined lithological categories of sedimentary, igneous and metamorphic origin. This initial identification of IRD lithology was performed based on all available visual criteria including texture (crystallinity, grain-size), color and translucency (mineralogy), hardness and surface structures (e.g., cleavage) using a binocular microscope. This rock type classification is now being substantiated by polarized light microscopy of exemplary thin sections created from larger IRD clasts.</p><p>To established cumulative rock magnetic fingerprints of all IRD magnetic mineral assemblages, isothermal remanent magnetization acquisition curves of all sieve fractions as well as individual specimens of all the classified rock types have been measured. These records systematically revealed higher concentrations of magnetic minerals at the tops and bottoms of most Heinrich Event layers and also clear variations in coercivity spectra. This finding is mirrored by the IRD rock count records, where magmatic rock types predominate mostly at Heinrich Event layer boundaries. Preferred deposition of these IRD rock types during the initiation and ending of events and their variation from older to younger events,- highlight repetitive patterns in the cyclic Laurentide ice-sheet collapses to be further explored.</p>

Iceland-Scotland Overflow Water Transport Variability through the Deep Bight Fracture Zone

<p>Iceland Scotland Overflow Water (ISOW), a component of the deep limb of the Atlantic Meridional Overturning Circulation (AMOC), is the equilibrated product of dense overflow into the eastern North Atlantic basin.  Modeling results and recent observations have suggested that a significant westward transport of ISOW (~1x10<sup>6</sup> m<sup>3</sup>s<sup>-1</sup>) may occur through the Bight Fracture Zone (BFZ) near 57°N, the first major channel through the Reykjanes Ridge where ISOW can cross into the Irminger Sea.  The remaining denser (and deeper) ISOW has been shown to leave the Iceland Basin westward via the Charlie-Gibbs Fracture Zone near 53°N, or southward into the West European Basin. Until now, there have been no measured time series in the BFZ to validate model results. Single moorings placed in the north and south channels of the BFZ from summer 2015 to summer 2017 were used to estimate a mean combined transport across the fracture zone of 0.8 ± 0.4 x10<sup>6</sup> m<sup>3</sup>s<sup>-1</sup> westward, with each channel contributing about half of the mean transport. Variability between the two channels on shorter (month-long) times scales can be extreme: in March of 2016, for example, north channel transport was ~0.4 x10<sup>6</sup> m<sup>3</sup>s<sup>-1</sup> eastward, while south channel transport was ~0.8 x10<sup>6</sup> m<sup>3</sup>s<sup>-1</sup> westward.  For this 2-year period, transport is stronger in the summer (0.9-1.2 x10<sup>6</sup> m<sup>3</sup>s<sup>-1</sup>) than in winter (0.5-0.7 x10<sup>6</sup> m<sup>3</sup>s<sup>-1</sup>), where large fluctuations including complete reversals suggest transport variability may be affected by winter storms.  This mooring record also shows a fresh anomaly in ISOW beginning in early 2017, which has been shown by others to originate from the surface waters near the Grand Banks region of the western north Atlantic.  Transport variability in this two-year record is examined in the context of the transport variability of the OSNAP mooring arrays on the east and west flanks of the Reykjanes Ridge just north of BFZ during the same time period.  An observationally-based understanding of how the Iceland and Irminger basins communicate with each other via the deep limb of the AMOC through the BFZ will provide fundamental insight into the pathways and processes that define the subpolar AMOC system.</p>

Interferometric Synthetic Aperture Sonar as a tool for seafloor geological mapping on the Grand Banks offshore Atlantic Canada: preliminary results.

<p>With less than 20% of the seafloor mapped at a sufficiently high resolution for geological and biological studies (<50m), there is a need for new technological approaches to map and characterize the seafloor environment at higher resolutions. Here, we present preliminary results of an investigation into the use of interferometric synthetic aperture sonar (InSAS) as a new approach to help fill this gap. InSAS can provide very high-resolution acoustic imagery (3cm/pixel) and bathymetry (25 cm/pixel) as well as large coverage area (up to 150m across track per side while flying at a 15m altitude, at 6 knots). Compared to traditional sidescan sonars, high-resolution imagery in both along and across track directions is achieved by the synthetic aperture of the sonar array, which uses a large number of receiver arrays and a cm-size spacing between individual elements. This technique has so far mostly been used for military and industrial purposes.</p><p>Onboard the<em> Atlantic Kingfisher</em> in October 2020, we used Kraken Robotic Systems’ InSAS system on a <em>Katfish</em> towed vehicle to survey 85 km<sup>2</sup> of the Tail of the Grand Banks, the southernmost extremity of the continental shelf offshore Newfoundland, Canada. During a survey, the sonar is set at a center frequency of 337 kHz and survey planning included data coverage overlap for 140% coverage of the seafloor. Kraken Robotic’s processing algorithm and the towing optic cable allowed for real-time processing of the data and initial post processing using <em>Caris Onboard</em>.</p><div>We show one of the first applications of InSAS for geological studies. This system is excellent for identifying fine-scale geological features as well as variations of seabed texture and composition at a large scale on flat seafloor. We identified distinct seafloor sedimentary textures on the imagery, such as relatively homogeneously spaced alternations of high and low backscatter (BS) strength corresponding to well-defined ripple marks, as well as multiple 1-10m wide circular depressions of high BS strength surrounding individual rocks and a lower BS strength on the seafloor surrounding depressions. With high coverage, speed and resolution, InSAS represents an effective tool for environmental, biological and geohazard monitoring.</div>