Symposium Presentation Summaries

Abstracts

Abstracts are organized alphabetically by presenters’ last names. In the interest of brevity, only the presenting authors are indicated. Please note that abstract projects are the work of the presenter, as well as collaborators within the network. For more information, please contact the authors.

Oral Presentations

What is a smolt? Diversity of downstream migrating sea trout

Kim Aarestrup, Technical University of Denmark

We employed PIT tagging to investigate time at sea, return rate and straying of downstream migrating sea trout juveniles. The juveniles were divided into three groups based on morphology typically reflecting different developmental stages of smoltification (Smolt, Pre-smolt and Parr). 66 % was characterized as Smolt, 30 % as Pre-smolt and 4 % as Parr. There were several significant differences between the different morphs, including run timing, time at sea and return rate. Surprisingly, the smolt group had the lowest return rate and smaller individuals in the group had a higher return rate than larger smolt. Straying rate was 21 %, considerably over published values but was unrelated to the different morphs. However, straying rate was significantly higher for smaller fish. The results demonstrate the diversity of sea trout smolts and suggest different life histories may be related to the different morphs.

Aarestrup_OTNSymp2014_Summary

Cybercartographic Atlases as tools for knowledge mobilization: Potential applications in OTN

Claudio Aporta, Dalhousie University

Cybercartography is an approach to data integration and knowledge mobilization devised by professor D.F. Fraser Taylor of Carleton University. This presentation will describe the main concepts around cybercartographic atlases, based on the presenter’s past and current research in Arctic Canada and his collaboration with Fraser Taylor’s group. It will discuss the capacity of this tool to facilitate knowledge mobilization, and it will open the debate as to how this approach could be used in the context of the Ocean Tracking Network’s ongoing research, in the context of new developments currently taking place at Dalhousie University.

Movements of the deepwater flatfish, Greenland halibut (Reinhardtius hippoglossides), in the coastal fjords of Baffin Island

Amanda Barkley, University of Windsor

Deep-water (>500 m) marine ecosystems of the Arctic are poorly studied and largely unexploited, however recent changes in ice cover and duration are leading to the development of multiple Inuit artisanal flatfish fisheries. This raises concerns over the viability of these fisheries and the potential impact they may have on the populations of the main target species, the Greenland halibut (Reinhardtius hippoglossides). To assess some of these concerns an acoustic array was established at the north and south entrance to Scott Inlet as well as at the entrance to Sam Ford Fjord on Baffin Island, Nunavut in September 2012 and 39 Greenland halibut were tagged with acoustic transmitters. Of these tagged fish, only 14 were detected, however one additional fish which had been tagged in Cumberland Sound, approximately 1,100 km away from the current study site, was also detected moving along all three gates. Detections for the Greenland halibut are very low in the winter months from November to February, possibly coinciding with a spawning migration to the Davis Strait, although this is slightly earlier than the reported timeframe for spawning in this area. Larger fish tend to be located around receivers that are moored in the deepest sections of the gate, whereas smaller individuals are more evenly distributed. The establishment of four more gates in September 2013 as well as the addition of 71 more tagged fish to the system, will help elucidate the movement direction of this species as they may migrate further into the fjords or out into Baffin Bay. It is clear the populations of Greenland halibut in these northern fjords are highly connected and therefore management must take into consideration the migratory lifestyle of this species as it crosses multiple boundary lines.

Barkley_OTNSymp2014_Summary

Fisheries non-retention and latent mortality during the adult migration of Chinook salmon

Arthur Bass, University of British Columbia

Wherever commercial, aboriginal, or recreational fisheries exist, a proportion of the fish population experiences non-retention; defined as either intentional release from gear or interaction with gear followed by escape. While non-retained fish may appear to be healthy at release/escape, they may sustain sub-lethal impacts that lead to vulnerability to predation, latent mortality, or failed reproduction. Sub-lethal effects may be further magnified by physiological status, life history processes, and pathogen presence. These impacts can result in serious consequences for fish populations and may impose an anthropogenic selection pressure. Adult Pacific salmon performing spawning migrations through freshwater are an appropriate model for studying this phenomenon since: i) they are undergoing rapid physiological changes that make them more vulnerable to acute stressors, ii) there is a large diversity of fishery techniques and pressures along their migration corridor, iii) they carry and are exposed to a diversity of pathogens along their migration, and iv) latent mortality is relatively easy to measure due to high fidelity to natal watersheds. We studied the impacts of gillnet non-retention on Chinook salmon in the Chilliwack River, British Columbia. Adult Chinook received a simulated gillnet treatment and were biopsied and released with gastric radio tags. Telemetry stations monitored the following upstream migration. Quantitative PCR was performed on non-lethal gill clips to assess the pathogen load and diversity at release. Results from the 2013 field season will be presented.

Bass_OTNSymp2014_Summary

Atlantic Sturgeon Marine Depth Distribution in Bay of Fundy and Minas Basin: Insights from Acoustic and Archival Telemetry

Jeffrey Beardsall, Acadia University

Atlantic Sturgeon are highly migratory marine fish and spawn in freshwater portions of their natal river or estuary. Very little is known about their marine distribution, especially in the northern extent of their range (e.g. Bay of Fundy and St-Lawrence River). Pop-up satellite archival tags (PSATs) and acoustic telemetry were used to study the seasonal distribution of Atlantic Sturgeon in Minas Basin and Bay of Fundy. Atlantic Sturgeon occupy shallow (0-10m) water depth from approximately June – October, and they occupy relatively deep (40-100m) water depths from approximately October – April. Data presented are the first fishery-independent reports of Atlantic Sturgeon seasonal marine occupancy in the northern extent of their range, and the first reports of a potential international aggregation present in outer Bay of Fundy all year long. Collaboration with research groups along the Atlantic coast of North America will help determine Atlantic Sturgeons international presence in Canadian waters. Collaborations in the past year include combining acoustic and archival data sets with information from the Acadia Centre for Estuarine Research, Mount Allison University and the University of Maine. Network integration in the next year includes synthesis of marine distribution of sturgeons studied inside and outside OTN, and providing information on Atlantic Sturgeon movements and seasonality to DFO and OTN governance theme.

Beardsall_OTNSymp2014_FactSheet

Physical Oceanography of Cumberland Sound, Baffin Island, 2011-2013

Jeanette Bedard, University of Victoria

Cumberland Sound, an embayment on the southeast coast of Baffin Island opening into Davis Strait, with a maximum depth over a kilometre deeper than its sill, hosts commercially viable fish populations in the deepest depths. Each year, over 2011-2013, water cooled away from the surface reaching a temperature minimum at a depth around 100 m. Below the temperature minimum, water became warmer and saltier with depth and density each year converging below 400 m. Although, the temperature-salinity curves for each year followed a similar shape, the entire water column in Cumberland Sound changed between years, most dramatically at the temperature minimum. It was unlikely local processes played a significant role in influencing the entire water column, therefore an outside influence was required. External influences were evaluated over two layers through a collaboration with researchers at the University of Washington studying Davis Strait. At mid-depths, the cold Baffin Island Current bent into the sound along the north coast and exited along the south. The warm deep water was replenished from the recirculated arm of West Greenland Current occasionally flowing over the sill and down to a stable depth. This new understanding of the oceanography will be used to better interpret acoustic tracking data collected in the Sound, facilitating future collaboration with biologists working in the region.

Bedard_OTNSymp2014_Summary

Resilience or vulnerability? Temperature and oxygen thresholds of marine animals on the Scotian Shelf and in the Gulf of St. Lawrence in the context of environmental change

Laura Bianucci, Dalhousie University

While dissolved oxygen is vital for most marine animals, the response of different species to lowering oxygen concentrations can vary. Moreover, although hypoxic conditions are usually defined as environmental oxygen concentrations less than ~60 uM (~2 mg/L), many species can be negatively impacted at either higher or lower concentrations. Furthermore, water temperature also affects different aspects of marine life (e.g., reproductive success, aerobic performance, etc.). Here we present the application of a coupled physical-biological ocean model to investigate the impacts of decreasing oxygen and increasing temperature conditions in the ecosystems of the Scotian Shelf and Gulf of St. Lawrence. In particular, we evaluate different oxygen and temperature thresholds in the context of a climatological oxygen distribution and the coupled physical-biological model. Said thresholds are found in a comprehensive dataset that considers different types of thresholds (e.g., levels at which physiological stress is experienced, 50% mortality is attained, etc.) of important marine species found in these regions. The numerical model allows us to investigate the potential displacement of species under different scenarios (e.g., warmer ocean, oxygen-depleted offshore waters, combination of both), leading to an analysis of the resilience of the ecosystem.

Bianucci_OTNSymp2014_Summary

Using accelerometer tags to estimate post-tagging behaviour and stress response in captivity and in the wild

Franziska Broell, Dalhousie University

Conventional and electronic tags play an important role in estimating fish movements and activity. However, external tags can adversely affect fish behaviour, swimming efficiency and elevate stress levels resulting from tagging procedures and tag load. We use tri-axial microaccelerometers to assess immediate (acute) post-tagging behavioural response in shortnose sturgeon (Acipenser brevirostrum) in the wild and as well as longer-term (chronic) post-tagging response in captive Atlantic cod (Gadus morhua) tagged with differently-sized tags. First, we summarise the analytical techniques developed to determine stress-related behavioural response based on acceleration data. Using these techniques, we show that Atlantic cod present aberrant swimming behaviour (repetitive scouring) apparently associated with attempts to reduce tag load. We then demonstrate that elevated energy expenditure (maximum acceleration) during scouring is a function of tag load. Finally, we demonstrate that in the wild, immediate post-tagging behaviour is highly variable among individuals ranging from extended resting to elevated activity.

Broell_OTNSymp2014_Summary

Burst swimming in areas of high flow: delayed consequences of anaerobiosis in wild adult sockeye salmon

Nicholas Burnett, University of British Columbia & Carleton University

Wild riverine fishes are known to rely on burst swimming to traverse hydraulically challenging reaches, and yet there has been little investigation as to whether swimming anaerobically in areas of high flow can lead to delayed mortality. Using acoustic accelerometer transmitters, we estimated the anaerobic activity of anadromous adult sockeye salmon (Oncorhynchus nerka) in the tailrace of a diversion dam in British Columbia, Canada and its effects on the remaining 50 km of their freshwater spawning migration. Consistent with our hypothesis, migrants that elicited burst swimming behaviours in high flows were more likely to succumb to mortality following dam passage. Females swam with more anaerobic effort compared to males, providing a mechanism for the female-biased migration mortality observed in this watershed. Alterations to dam operations prevented the release of hypolimnetic water from an upstream lake, exposing some migrants to supra-optimal, near-lethal water temperatures (i.e., 24°C) that inhibited their ability to locate, enter and ascend a vertical-slot fish way. Findings from this study have shown delayed, post dam passage survival consequences of high-flow-induced burst swimming in sockeye salmon. We highlight the need for studies to investigate whether dams can impose other carryover effects on wild aquatic animals.

Burnett_OTNSymp2014_Summary

Applications and Potential of OTN Autonomous Vehicles

Adam Comeau, Dalhousie University

The Ocean Tracking Network (OTN) glider group operates two types of autonomous vehicles which can track tagged marine animals, upload data from underwater acoustic receivers, and measure oceanographic parameters relevant to studying marine animal movements. The first type of autonomous vehicle, the Liquid Robotics Wave Glider, remains at the surface and uses wave energy for propulsion and solar energy to power on-board sensors. The second type, the Teledyne Webb Research Slocum Gliders, is a battery powered robotic submarine that can submerge to 200 m. Both the Wave Glider and the Slocum Glider are equipped with VEMCO VMT acoustic monitoring receivers. The Wave Glider has the additional capacity of integrating telemetry detections into its live data stream, transmitted to shore via Iridium satellite service. Having acoustic receivers such as these on autonomous platforms allows for adaptive sampling such as following animal migration routes or range testing sentinel tags. The Wave Glider can offload telemetry data from underwater VEMCO VR4-UWM receivers under high winds and heavy sea states with the ability to transmit data to shore. A test mission off of Halifax, NS, demonstrated this capability by offloading data from 78 VR4-UWM’s, saving OTN money and time. Our autonomous vehicles collect high resolution measurements of oceanographic parameters near and above the sea surface with the Wave Glider and throughout the water column with the Slocum Glider. Measured variables include wind speed and direction, wave height, water temperature, dissolved oxygen concentration and estimated phytoplankton concentration. An echo sounder is being integrated into a Slocum Glider which will be used to estimate zooplankton density. The capabilities of these gliders continue to evolve as new sensors become available. OTN autonomous vehicles are robust platforms that can be used to support multiple programs within OTN and collect data about animal movements and the marine environment in cost-efficient and innovative fashion.

Comeau_OTNSymp2014_Summary

Delayed mortality of adult coho salmon bycatch in commercial seine fisheries in coastal waters of British Columbia

Katrina Cook, University of British Columbia

Many commercial purse seine fisheries for Pacific salmon in British Columbia are regulated based on mortality rates of released bycatch. Fishing mortality limits are therefore established within each management area but reliable or scientifically defensible assessments of mortality rates and stock compositions are rarely conducted. Interior Fraser River coho salmon are listed as endangered, but unfortunately a common bycatch species during pink salmon fisheries. If the current mortality rate for these coho is erroneously high, commercial fishers may be losing economic opportunities but if low, even stricter conservation measures may be required. A commercial purse seine vessel and crew were chartered to operate a simulated pink salmon fishery and all operational and handling practices were as in a real fishery. Telemetry, non-lethal biopsies and DNA sampling of coho bycatch to determine stock composition and mortality rates were combined with on-board holding studies to understand the short-term physiological processes associated with marine handling stressors and examine the consequential development of pathogens and disease. The results provide information directly applicable to management of commercial purse seine fisheries in British Columbia coastal waters while also elucidating potential mechanisms of mortality.

Cook_OTNSymp2014_Summary

South Africa’s Acoustic Tracking Array Platform (ATAP): history, status, challenges and opportunities

Paul Cowley, Rhodes University

A commitment made in 2011 by the Ocean Tracking Network (OTN) project to loan telemetry hardware in the form of automated data-logging acoustic receivers lead to the development of a large-scale acoustic monitoring array in South African coastal waters. Additional capital equipment support from the National Research Foundation formalized the establishment of the Acoustic Tracking Array Platform (ATAP), managed by the South African Institute for Aquatic Biodiversity (SAIAB). The ATAP, incorporating OTN, collects data from approximately 200 receivers moored around the coastline. Ten key monitoring sites are located from Cape Town on the south west coast to Ponto Do Ouro (Mozambique) on the east coast of southern Africa, with two more sites planned for KwaZulu-Natal. In addition, at least 15 estuaries are equipped with acoustic receivers. A registry of tagged animals maintained by ATAP and its collaborating partners from 17 research agencies suggests that the network currently collects data from approximately 350 tagged fish belonging to 12 species. Most of the tagged fish have been recorded by the array yielding approximately two million detections. The development of this significant marine research platform has past and future challenges, which include: working in a hostile marine environment, securing buy-in by researchers to ensure broader collaboration efforts, servicing and maintaining equipment, developing and managing a local database, integrating with the global OTN project and securing adequate long-term funding. SAIAB is however committed to maintain the ATAP receiver network until the end of 2018, thereby providing an unprecedented opportunity to gather long-term fish movement/migration and environmental data around the southern tip of the African continent. In this presentation I will provide an overview of ATAP’s history and current status. Lastly, by making use of selected examples, I will highlight the opportunities that exist to improve our understanding of the spatial ecology of marine animals. Such information is much needed to assist with the corrective management of over-exploited fishery species and conservation of threatened or endangered species.

Cowley & Murray_OTNSymp2014_Summary

Bio-physical interactions between Atlantic Salmon and coastal conditions along the Halifax Line

Mathieu Dever, Dalhousie University

To better understand Atlantic Salmon migration patterns, it is crucial to first thoroughly characterize the environment through which they migrate. As part of the first theme of the Ocean Tracking Network, our study focuses on describing the observed temperature and salinity distribution, as well as the structure of the currents across the Halifax Line. Estimations of geostrophic alongshore transport based on glider observations reveal a strong coastal current (i.e. The Nova Scotia Current) but also demonstrate that both the transport and the location associated with the current are highly variable on the seasonal and inter-annual timescales. These measurements and information were then integrated with acoustic detections collected along the Halifax Line. Key fish in this analysis were hatchery-origin Atlantic Salmon tagged in the Penobscot River (ME, USA) between 2008 and 2013, detected on the Halifax Line 3 to 5 weeks later as post-smolts. The analysis then explores the correlation between detection rates, spatial distribution and temporal distribution with ocean temperature, chlorophyll concentration and current velocity collected from several platforms such as underwater gliders, moored ADCPs and satellites. Results show that both the average detection distribution and its inter-annual variability can be related to the environmental conditions and coastal current along the Halifax Line.

DEVER_OTNSymp2014_Summary

Environmental and physiological associations with homing sockeye salmon behaviour in an estuary

S. Matthew Drenner, University of British Columbia

The reproductive migration of anadromous salmonids through estuaries is one of the most challenging migratory stages of their life cycle, yet little is known about the environmental and physiological conditions that influence behaviour. We captured, physiologically sampled, tagged and released ~ 365 sockeye salmon homing through coastal waters towards the Fraser River, British Columbia, Canada. Telemetry was used to assess individual sockeye salmon movements and model selection was used to relate environmental and physiological conditions to migration behaviour in the estuary and at river entry. Sockeye salmon tended to use the west side of the estuary along the coastline, and migration in the estuary and into the river occurred mostly during the day and on ebb and flood tides. Model selection revealed that sockeye migration rate in the estuary is associated with wind-induced currents, discharge from the Fraser River, biopsy of tissues, and an individual’s energetic state, but these factors were location and population dependent. We hypothesize that high discharge and wind-induced currents exposed sockeye salmon to a stronger Fraser River signal and lower salinities. This in turn resulted in faster migration rates due to either an increased ability for olfactory navigation, accelerated maturation through a neuroendocrine response to olfactory cues, or accelerated osmoregulatory shift towards fresh water acclimation. Furthermore, sockeye salmon that had lower energy reserves and underwent physiological biopsy migrated faster into the river, but associations were stock dependent. Results suggest that future changes to the timing of spring freshet and wind patterns could affect sockeye salmon movements and ability to navigate during their reproductive migration in the estuary.

Drenner_OTNSymp2014_Summary

Foraging ecology and diet of bowhead whales in Cumberland Sound, NU

Steve Ferguson, Fisheries and Oceans Canada & University of Manitoba

Changes in zooplankton species composition are expected to occur as a consequence of environmental change, which may affect the foraging success of bowhead whales (Balaena mysticetus). However, the manners in which bowhead whales will respond to environmental changes are unknown. To begin to answer questions regarding species level responses to climate change, it is important to develop an understanding of dietary requirements. However, relatively little is known about bowhead diet and foraging ecology in the eastern Canadian Arctic. We sought to collect information about bowhead prey and feeding behaviour by opportunistically combining zooplankton and bowhead dive data in Cumberland Sound, Nunavut. Bowhead whales were equipped with archival SPLASH tags that track movement patterns of individuals using satellite telemetry and depth-temperature profiles. Individuals were tagged in Cumberland Sound during August 2012 and zooplankton samples (n=12) were collected between 22 and 26 August near whales in Kingnait Fiord. Two 333-micrometer (μm) mesh conical nets 30 cm and 60 cm in diameter fitted with a General Oceanics helical flow meter and temperature depth recorder were used to sample surface waters (0.5 m), and the water column using oblique (15 m) and vertical (180-220 m) hauling methods. Successive vertical tows of progressively shallower depth strata was also conducted. One tagged whale was in Kingnait Fiord during prey sampling and 90% of the whale’s dives were square-shaped (bottom time >50% total dive duration) deep dives (~197 m) suggesting the whale was feeding near the sea bottom. Zooplankton collections made in adjacent surface waters were devoid of prey. However, vertical samples collected between 0-230 m contained comparatively high concentrations of calanoid copepods (e.g., Pseudocalanus spp., Calanus hyperboreus and C. glacialis). Results from the successive vertical tows (0-200 m, 0-120 m, 0-95 m, 0-40 m) demonstrated that the highest concentrations of prey were contained in depth bins 0-200 and 0-120 m. Given these preliminary results, it appears as though bowhead whales feed at depth on calanoid copepods in Kingnait Fiord during the Summer. Fine-scale tagging and zooplankton sampling will be conducted during August 2014 to validate assumptions regarding bowhead foraging behaviour.

Ferguson_OTNSymp2014_Summary

Behaviour and survival of outmigrant sockeye salmon smolts

Nathan Furey, University of British Columbia

Migration behaviour and survival of sockeye smolts outmigrating from Chilko Lake, British Columbia were investigated using acoustic telemetry from 2010-2014. Over this time period, approximately 1600 smolts were tagged and their fate tracked for up to 1000 km to the Queen Charlotte Strait (QCS). The annual mean duration for this portion of the migration ranged between 37 and 45 days, with last detections occurring in mid- or late June in each year. Both migration rates and survival were location-specific. Movement rates were fastest in the freshwater environment, particularly in the Fraser mainstem where rates sometimes exceeded 200km*day-1. Movement rates in the coastal marine environment were generally less than 25 km*day-1. Survival during the freshwater portion of the migration ranged between 29% and 35% among years. Survival from the Fraser River mouth to the Northern Strait of Georgia (NSOG) was high and stable, exceeding 90% per day in all four years. The segment between the northern Strait of Georgia (NSOG) and QCS, however, was lower and more variable (ranging between 17% and 61% among years). The identification of areas of low or variable survival, as well as location specific residence times, allow for the generation of new hypotheses regarding factors influencing survival during this important life stage.

Furey_OTNSymp2014_Summary

Effects of predation on telemetry-based survival estimates: insights from a study on endangered Atlantic salmon smolts

Eddie Halfyard, Dalhousie University

Acoustic telemetry is increasing being used to estimate population-level survival rates. However, these estimates may be impacted by detection efficiency of receivers and are reliant on the assumption that telemetry data represent the movements of the tagged (i.e. targeted) fish. Predation on tagged fish confounds survival estimates and, unlike the issue of detection efficiency, methods to deal with predation have yet to be developed. In an effort to incorporate predation into survival estimates, a suite of eleven summary migration metrics were compared between Atlantic salmon smolts (Salmo salar) and striped bass (Morone saxatilis) in 2008 and 2011. Cluster analyses revealed that 7% to 27% of tags implanted in smolts exhibited migration patterns similar to striped bass, which could be interpreted as evidence of predation. The “fate” of smolt tags detected exiting the study site was re-assigned as “predated / died” and subsequently, estimates of survival were adjusted accordingly. Compared to a traditional mark-recapture model, the cluster analysis-adjusted approach reduced estimated survival from 51.8% to 43.6% and from 36.4% to 22.7%. It is unclear whether model-based approaches can resolve all issues associated with the complicating effects of predation. Limitations of this technique will be discussed, including recommendations for future efforts.

Halfyard_OTNSymp2014_Summary

OTN and AATAMS – 5 years and going strong

Robert Harcourt, AATAMS Facility Leader

The reproductive migration of anadromous salmonids through estuaries is one of the most challenging The first OTN installation in Australia was deployed off Perth in 2009 and helped form the cornerstone for the new Australian animal tagging network AATAMS, a fundamental component of Australia’s Integrated Marine Observing System (IMOS). Five years later AATAMS and OTN continue to thrive with a strong and growing relationship. AATAMS now has an online centralised database with over 120 registered users across 34 institutions and 60+ research projects. There are 93 species tagged in Australian waters and registered with AATAMS. We have nearly 5000 receivers in the network and well over 40 million detections in the AATAMS database. AATAMS with OTN is fundamentally changing our understanding of nearshore movements and migratory patterns of a multitude of commercial and endangered marine species.

Harcourt_OTNSymp2014_Summary

Advances in Obtaining Environmental Data from Free Swimming Animals

Kim Holland, University of Hawaii

Telemetry studies of free ranging marine animals have progressed beyond simply asking ‘where do they go?’ to also collecting and transmitting information about the environment through which the animals are moving. Transmitting this information in real time is complicated by the brief time that many animals are at the surface and by intermittent availability of a satellite ‘footprint”. Here we describe advances in improving data throughput by establishing shore-based receivers to augment satellite coverage.

Residence and Distribution of Arctic Cod (Boreogadus saida) in Resolute Bay, Lancaster Sound

Steve Kessel, University of Windsor

With climate change resulting in unpredictable sea ice conditions from year to year, it is crucial to gain a more comprehensive understanding of the knock on effects to the Arctic marine ecosystems. Resolute Bay, Cornwallis Island (74° 44’ N, 095° 04’ W), is an important hunting ground for the local Inuit population and a historically known site for Arctic cod (Boreogadus saida) aggregations. Arctic cod are believed to be a key stone species in the Arctic marine ecosystem, serving as a food source for members of higher trophic levels, including ringed seals (Pusa hispida), beluga whales (Delphinapterus leucas) and narwhales (Monodon monoceros), all of which are important targets for the local hunting community. Little is known of the behaviour and movements of Arctic cod, which in turn may be driving large-scale marine mammal migrations throughout the Canadian Arctic Archipelago (CAA). Thus, understanding the dynamics of Arctic cod within the Resolute Bay ecosystem, both in relation to sea ice dynamics and the behaviour/movements of the other marine organisms, will provide critical insight to expand our understanding of Arctic marine ecosystems as a whole. To investigate the residency and distribution of Arctic cod, an acoustic receiver array of 60 Vemco VR2W 180 KHz was established and 85 Arctic cod from four locations in the bay were captured, measured, weighed and implanted with Vemco V6 acoustic tags. Following an 86 day period of extended residence in the bay area, all but three individuals exhibited a collective departure. During this absence 51 Arctic cod were detected on the outside gate monitors, ~2 km outside of the mouth of the bay. Following the 14 day absence, 49 Arctic cod collectively returned to the bay array and the rest were not detected inside the bay again. After a 65 day long second residence inside the bay, again all but the same three individuals displayed a collective departure and eight cod were then detected on the outside gate monitors. Monitor site Residence Index (RI) analysis revealed a strong site fidelity toward the west and north areas of the bay. Capture location within the bay did not influence site fidelity during the residence periods, however, did appear to influence detection timing and distribution on the outside gate monitors. This data indicates that Arctic cod do exhibit an extended residence within Resolute Bay, both during open water and ice cover periods. Simultaneous monitoring of environmental parameters and marine mammal presence/ absence was conducted, and it is anticipated that further analysis of this data will help to explain the timing and distribution of Arctic cod within this system.

Great Lakes Acoustic Telemetry Observation System (GLATOS): Past, Present, and Future

Charles Krueger, Great Lakes Fishery Commission

In 2010, the acoustic telemetry observation system in the Laurentian Great Lakes (GLATOS) was established through funding from the Great Lakes Restoration Initiative to the Great Lakes Fishery Commission. Strategies used to launch GLATOS focused on developing regional expertise, designing flagship research projects, establishing a data management schema, and fostering communication among telemetry users. In addition, we sought to learn from organizations such as the Ocean Tracking Network (OTN) on how best to establish and maintain GLATOS. Anticipating rapid growth in the use of acoustic telemetry, an early goal was to establish and maintain a community of telemetry users to minimize negative interactions (code collisions) and encourage sharing resources. Two experienced PIs were attracted to work in the basin. Five research projects, designed to improve invasive species control, fisheries management, and native fish restoration, were funded. Recognizing the need to standardize data among projects and to ensure compatibility with other networks, GLATOS adopted a modified version of the OTN data schema. Data management has been continually addressed but is still evolving and will include hiring a data base manager. Communication needs have been met through creation of a website in 2011 (including an interactive receiver map and project home pages) and through annual coordination meetings with all investigators. Through 2013 (~4 years), more than 3700 fish were tagged and released representing 30 species. Projects have required 2,280 receiver deployments at 642 receiver stations. More than 105 million tag detections have been recorded (includes sentinel tag detections). Major challenges exist in the future and include the need to overcome the flood of data, the need to show scientific productivity in terms of published peer reviewed papers, the requirement to make the findings understandable and usable to managers and make a difference in the management of Great Lakes fishes, and to secure a long term funding source.

Krueger_OTNSymp2014_Summary

A seasonal examination of species interactions in Scott Inlet – preliminary findings and future research

Marianne Marcoux, Institut des sciences de la mer, Université du Québec à Rimouski 

Monitoring of Arctic marine ecosystems is increasingly needed because of accelerating exploration and development in the Arctic. For example, a newly proposed fishery for Greenland halibut in Nunavut requires an investigation of the interactions between this species and its predators to forecast the impacts on the ecosystem. Our research examines the distribution of keystone species and their interactions throughout the year in Scott Inlet, Nunavut. We used passive acoustic monitoring (PAM) to detect the presence of marine mammals in combination with acoustic telemetry to detect the presence of tagged fish and sharks at a detection array from September 2012 to May 2013. An automated detector was used to extract narwhal clicks from PAM recordings. Recordings were also manually examined to detect the presence of bowhead whales, walruses, and bearded seals. The timing of PAM detections of marine mammals were compared with the passages of Greenland sharks and Greenland halibut at the telemetry detection array. We found that species presence was influenced by ice cover. Narwhals, bowhead whales, Greenland sharks and Greenland halibut were detected before the ice was formed while walruses and bearded seals were only detected after the ice was formed. Collaborative work of this nature provides a unique opportunity to look at the interactions between multiple species of both marine mammal and fish, as well as their seasonality. Future work aims to examine marine mammal calls in detail to infer their behaviour and feeding activity, as well as the redeployment of PAM recorders at different locations to investigate movement between recorders.

Marcoux_OTNSymp2014_Summary

A synthesis of salmon tracking studies in the Pacific Arena

Eduardo Martins, Carleton University

The OTN Pacific Arena research focuses on juvenile (i.e. smolts) and adult migrating Pacific salmon in the Fraser River. More specifically, the research aims to understand how environmental, physiological and anthropogenic conditions influence Pacific salmon behaviour and survival en route to spawning grounds (adults) and to the marine environment (smolts). Biotelemetry and biologging techniques have been employed in conjunction with correlational and experimental approaches to address a diversity of research questions. In this presentation, we will synthesize recent findings of all salmon tracking studies conducted since 2009 in the Pacific Arena relating to the effects of: 1) ocean conditions and physiological state on thermal behaviour and migratory speed of adults in coastal areas; 2) fishery activities on post-release/escape survival of adults; 3) olfactory cues and high flows in a regulated river on the survival of adults; 4) tagging on behaviour and survival of smolts and adults; and 5) pathogens on survival of smolts during their migration through the Fraser River and coastal areas. These findings have been used to inform fisheries management and conservation of Pacific salmon in the Fraser River and successfully contributed to the OTN’s mission of generating information on movements of aquatic animals and using that knowledge to foster conservation.

Martins_OTNSymp2014_Summary

Effects of daily varying olfactory cues on Pacific Salmon migration success in a river regulated by hydropower generation

Collin Middleton, University of British Columbia

Olfaction is the primary sensory mechanism used to guide the homing of adult Pacific salmon (Oncorhynchus spp.) in their freshwater spawning migrations to natal streams. These migrations require complex decision-making and are reliant on odours of natal areas remaining unique and constant from year to year. Increasingly, rivers are physically transformed and regulated by diversion and impoundment, modifying natural flow regimes and hence potentially altering amounts or types of natal odors. To date, few studies have examined how hydropower systems can affect the composition of homestream cues and the compounding effects this can have on olfactory-guided migratory behavior and survival. We used radio telemetry to monitor upstream migration rates and survival of adult sockeye (O. nerka) and pink (O. gorbuscha) salmon in southwestern British Columbia as they passed from the Fraser River into the Seton River and through the Seton fishway enroute to spawning grounds. Natal odours in the Seton River are likely altered by inputs from an adjacent stream (Cayoosh Creek) whose flows are regulated through hydropower operations. We examined daily changes to the migratory corridor and the relative contribution of Cayoosh Creek water to Seton River water and found that when Cayoosh contribution exceeded 30%, sockeye survival to spawning grounds was impaired, though migration rates were not affected. Females incurred the highest rates of mortality. Our results will be discussed in the context of evaluating broader fisheries impacts of the current hydro operations and whether operational changes can improve fish passage to spawning grounds.

Thermal behaviour of adult sockeye salmon (Oncorhynchus nerka) in a regulated watershed following multiple stressors

Vanessa Minke Martin, University of British Columbia

Sockeye salmon (Oncorhynchus nerka) are susceptible to thermal stress, and recent high summer water temperatures in the Fraser River have been associated with reduced survival of migrating adults. Pacific salmonids behaviourally thermoregulate in response to stress, accessing available thermal refugia from stream inputs and stratified lakes. Gate’s Creek sockeye must traverse a vertical-slot fishway and two natal lakes to access their spawning grounds in the Seton-Anderson watershed, British Columbia. Dam passage represents a significant stressor for some fish, with fewer female fish passing successfully. In 2007, we found that more reproductively advanced females with lower levels of energy transited through cooler portions of the lakes compared to less mature females with high levels of energy, possibly to reduce metabolic energy expenditure and delay final maturation. Transit temperatures of males were not related to physiological variables. In 2013, we used radio telemetry and internal temperature loggers to assess thermal behaviour of sockeye that successfully reached spawning grounds, in response to stress associated with investigator handling and fishway passage. Three hundred and five fish were tagged and released in four locations in the watershed, reflecting different levels of transport and handling and individual thermal experiences were reconstructed from 43 temperature loggers recovered on spawning grounds. Sex-specific thermal behaviour was assessed, to determine if female fish transited through cooler temperatures following dam passage than males, as in 2007, and whether level of transport and handling affected these patterns.

Minke-Martin_OTNSymp2014_Summary

Transcending the Disciplines

Vivian M. Nguyen, Carleton University

Scientific research has long supplied evidence and information to support conservation and sustainable management of the world’s natural resources, yet there is still a large gap between science and action due to the complexity of the conservation issues. Several calls have been put forth for interdisciplinary and transdisciplinary approaches and research to overcome barriers to successful conservation action, and the need to train genuinely transdisciplinary thinkers and form interdisciplinary/transdisciplinary teams. I provide a personal narrative of my experience doing transdisciplinary research using the Pacific salmon fisheries in the west coast of Canada as a case study.

Nguyen_OTNSymp2014_Summary

Using numerical particle-tracking to study the movement of the American eel and the Atlantic sturgeon

Kyoko Ohashi, Dalhousie University

We present two examples of the use of a numerical particle-tracking scheme, in combination with time-varying, three-dimensional fields of numerically simulated hydrography and circulation, in the study of marine animals. The first example is our ongoing study of the American eel’s behaviour during the portion of its spawning migration from the St. Lawrence Estuary to the open ocean. The second example is the search for overwintering sites of the Atlantic sturgeon in the Bay of Fundy. Passive particles are numerically tracked backwards in time to simulate the movement of tags between the time they reach the surface (after becoming detached from sturgeon in the subsurface) and the time of their first satellite detection. We also discuss possible future work on the Atlantic sturgeon’s migration into the Bay of Fundy, which is undertaken predominantly by those from the nearby Saint John River but is known to include some from as far away as Hudson River in New York.

Ohashi_OTNSymp2014_Summary

Oceanography and Acoustic Research in Resolute Bay, Nunavut

Caitlin O’Neill, University of Victoria

Resolute Bay, a remote Arctic bay opening into Parry Channel, hosts diverse populations of marine mammals and fish at various times each year. The focus of this study is to link physical oceanographic conditions to mammal migrations and/or their food supply. Both oceanographic and acoustic data has been collected with plans to continue data collection. Salinity, temperature, and depth (CTD) profiles were made in multiple locations throughout Resolute Bay during summer 2012 and 2013, and more CTD profiles will be collected this summer. Two oceanographic moorings, measuring temperature, salinity, depth, and dissolved oxygen, were deployed in summer 2012 and three were deployed in summer 2013, including a vertical array of thermistors above one of the moorings. For four months in 2012 and 2013, two C-PODs measured click sounds from Beluga whales and Narwhals that migrate into Resolute Bay to feed every fall. Additionally in 2013, an acoustic recorder was deployed to record a broad spectrum of marine mammal vocalizations, vessel presence, and ambient noise. The moorings and C-PODs will be retrieved and redeployed this summer. The oceanographic and acoustic data collected will be used in collaboration with researchers at University of Windsor and East Carolina University, who have collected fish tracking and hydroacoustic data in Resolute Bay. Future collaborations would be beneficial with Arctic marine mammal DFO scientists and other OTN students working with oceanographic data.

ONeill_OTNSymp2014_Summary

Facing the river gauntlet: understanding the effects of bycatch on the physiology of coho salmon

Graham Raby, University of British Columbia

Experimental research with physiological endpoints can be used to understand causes of mortality and sublethal effects in fish caught and released by fisheries in waters that are warming due to climate change. In British Columbia, Canada, an endangered population of coho salmon is caught and released by multi-sector fisheries in both the marine environment and freshwater while en route to spawning areas. We used hatchery-origin coho salmon that had recently transitioned from the marine environment to examine physiological responses to a capture simulation where fish were netted in large groups at two different temperatures and for two different durations. We simultaneously used a combination of surgically-implanted heart-rate biologgers, blood and tissue biopsy, and respirometry to monitor physiological recovery for 24 h. Recovery of blood and white muscle metabolites was generally complete in 4 h, while heart rate appeared to take somewhat longer. Our data illustrate the utility of monitoring multiple physiological endpoints to assess animal welfare and sublethal impacts in the context of bycatch. Fishers participating in the beach seine fishery should be encouraged to minimize handling times for coho salmon bycatch, particularly at high temperatures.

Raby_OTNSymp2014_Summary

From 3 minutes to 3 lines: sharing fisheries research in creative ways

Natalie Sopinka, University of British Columbia

OTN bioprobes and roboprobes share important information with us, but how can we share this information with each other and the public? Whether you listen, read and speak or tweet, like and follow, communicating your OTN research in an engaging manner can grab the attention of and educate local, national and global audiences. From academic conferences and peer-reviewed journals, to youth naturalists and candidly creative blogs, I’ve shared my PhD research on the maternal effects of stress in sockeye salmon (Oncorhynchus nerka) in 8000 words, 3 minutes and 17 syllables. Here, I present ways to venture into the world of storytelling and social media, where first person writing is encouraged, a picture is worth a thousand words, and fisheries research is accessible by all.

Sopinka_OTNSymp2014_Summary

The Char Tracker Story

Aaron Spares, Dalhousie University

The influence of salinity, temperature, tides and prey availability on the marine migration of forty-three anadromous Arctic char Salvelinus alpinus (523 ± 97 mm LF, mean ± SD) in inner Frobisher Bay (63° N 68° W), Canada, was examined from July-September 2008/2009. Most detections were in surface waters (0 to 3 m). Inter/sub-tidal movements and consecutive repetitive dives (maximum 52.8 m) resulted in extreme body temperature shifts (-0.2 to 18.1°C). Approximately half of intertidal and subtidal detections were between 9 to 13°C, and 1 to 3°C, respectively. Stomach contents and deep diving suggested feeding in both inter/sub-tidal zones. Detected S. alpinus were either continuously (maximum 34 days) or intermittently present in estuarine zones, on average residing approximately ⅓ of time tracked and returning once every 9 days. Significantly higher estuarine residency during the final 15 migration days suggested a transition phase may occur prior to freshwater re-entry. Low travel rates during flood tide suggested migrants staged before accessing intertidal/estuarine zones. Although the main estuaries are approximately 22 km apart, a considerable portion of tagged migrants used both (19%). Approximately half of migrants exhibited extra-estuarine travel, mostly during mid-migration, and remained near shore (< 3 km) within 30 km SLD of either estuary. We concluded inner Frobisher Bay S. alpinus (1) spend a significant portion of their migration within/adjacent to, and (2) have a restricted marine distribution within 30 km SLD of, two major estuaries. We suggested inter/sub-tidal zone movements related to behavioural thermoregulation and optimal prey availability. Northern collaborations included DFO Iqaluit, Nunavut Arctic College, Nunavut Research Institute and Amarok HTA. Consulting on char, and other northern research projects has continued since.

Spares_OTNSymp2014_Summary

Spatial variation in ringed seal foraging behaviour across the Arctic

Dave Yurkowski, University of Windsor

Marine resources such as food and suitable habitat vary in quality and consist of a heterogeneous distribution. The Arctic is a region of seasonal extremes influencing resource abundance. However significant changes are occurring due to a warming climate, which may impact the behaviour of Arctic species. Ringed seals are an abundant, key species that provide a fundamental link between lower and upper trophic levels. Our objective was to quantify ringed seal movements, foraging behaviour across the Arctic using Bayesian Switching State-Space models. Ringed seals have been tracked with satellite-relay data loggers from Sanikiluaq (n=80) and Resolute (n=7), Nunavut, Canada and Melville Bay, Greenland (n=13). As part of a new collaboration with DFO, an additional 15 individuals from the Amundsen Gulf region have been analysed. Ringed seals consistently foraged at shallow depths close to shore in all locations, although some offshore feeding behaviour occurred in the Amundsen Gulf individuals. Profound behavioural differences occurred spatially with Greenland ringed seals residing in a restricted area throughout the year compared to other areas. In addition, seals captured from Resolute and the Amundsen Gulf area traveled significant distances in excess of 3,000km, which has not been previously observed in this species. Results will identify critical ringed seal habitats, which will contribute to management of anthropogenic pressures, such as increased shipping and development activity on the Arctic ecosystem.

Yurkowski_OTNSymp2014_Summary

Poster Presentations

Free-ranging marine mammals, the next ‘Ships of Opportunity’?

Laurie Baker, Dalhousie University

The miniaturization of environmental sensors and acoustic tags has allowed an increasing number of these instruments to be deployed on animals. Paired with GPS satellite location telemetry, animal-borne instruments provide a unique opportunity to collect fine-scale information across broad-geographic ranges and habitats that may be inaccessible due to the high costs of sampling or seasonal limitations (e.g. sea ice cover). As ‘adaptive samplers,’ animals go to biologically interesting and productive regions. Thus, in addition to providing information relevant to the animal’s behaviour, animals may also be used as bioprobes to collect fine-scale data that can complement oceanographic models. This method of sampling differs from that of traditional surveys, because sampling locations are non-random and cannot be predetermined. In order to draw accurate biological inferences and appropriately use this data to inform oceanographic models, we must account for these biases in sampling effort. This next phase of my Masters focuses on accounting for these biases by quantifying a bioprobe’s sampling effort in terms of where, when, and how long they are in an area.

Baker_OTNSymp2014_factsheet

The challenge of tracking Eels during their marine migration

Mélanie Beguer, Université Laval, Québec & Dalhousie University

The marine migration of adult eels remains a complete mystery, even after over a century of research. One important objective of our project is to help fill this knowledge gap. To this end and since fall 2011, we have equipped a total of 33 American eels with pop-up satellite archival tags –PSAT- in an attempt to follow them during their oceanic migration to the Sargasso Sea. Two kinds of PSAT were used: X-tags (Microwave Telemetry) and SeaTag GEO (Desert Star Company). In all experiments, all tags popped-up prematurely, i.e. before the programmed release date. PSAT-tagged eels released in the Gulf of St. Lawrence suffered heavy predation by Porbeagle sharks. Temperature-depth profiles recorded before the predation events revealed marked diel vertical migrations and showed eels most likely remain in the Laurentian channel while in the Gulf. In the second experiment, eels were released off Nova Scotia and four of them retained their tags for up to 60 days and 800 km from the coast, showing unexpected southeast trajectories. As eels avoid the euphotic zone during daylight, no light data are available during the tracking period, preventing us from using geolocation methods that are typically based on light-level data. In collaboration with physical oceanographers from Dalhousie University (OTN Theme I.1), we are thus developing methods based on environmental data recorded by the tags (temperature, depth, total magnetic field intensity) to reconstruct their trajectories at sea. In parallel, some passive particle-tracking is also conducted to evaluate how ocean currents may have contributed to the fish’s movement. We also developed a coupled biophysical particle-tracking model to evaluate various behaviours that allow both American and European eels to reach the spawning grounds within a prescribed timing window. It shows that both species need oriented migratory behavior and that energy expenditure is not a critical limiting factor. Over the coming year, new field tracking is planned (during fall) and the collaborative work with the physical oceanographers will continue.

Beguer_OTNSymp2014_Poster

Striped Bass overwintering in the Mira River estuary, Cape Breton, Nova Scotia

Colin Buhariwalla, Acadia University

Striped Bass Morone saxatilis in Atlantic Canada overwinter in estuaries and tributaries of the southern Gulf of St. Lawrence and Bay of Fundy, however, overwintering has not been reported on Cape Breton Island, NS. Using acoustic telemetry, an annual overwintering aggregation of Striped Bass was identified in the Mira River estuary from 2012-2014. Tagged fish (n = 28; 47.9 – 90.6 cm total length) migrate to the overwintering site at the end of November and occupy depths of 6.0 ± 1.2 m (n = 7; mean ± SD) and salinities of 17 to 19. Striped Bass tagged with multi-year acoustic tags (n = 6, 2012; n = 5, 2013) leave the overwintering site at the end of April and remain within the system throughout the spring, suggesting a Mira River spawning population. Identification of overwintering and spawning sites outside of the Bay of Fundy and southern Gulf of St. Lawrence changes our understanding of the species’ distribution at the northern extreme of its range and will need to be incorporated into future Striped Bass fisheries management decisions. Collaboration on this project includes external and internal OTN partnerships, with external partners at Eskasoni Fish and Wildlife, NYU Department of Environmental Medicine, and Nova Scotia Department Fisheries and Aquaculture Inland Fisheries Division. Collaborations included obtaining samples, DNA analyses, field support, providing sampling instruction, DNA collections, and angler education. Within OTN collaboration consisted of HQP training in sampling, recording and submitting meta data, receiver maintenance, deployment and recovery, measuring physical variables within the system, and sample collection. Network integration in the forthcoming year will be achieved through genetic information compilation centered at NYU but including OTN Atlantic partners and new stock structure information provided to DFO and OTN Ocean Governance group.

Buhariwalla_OTNSymp2014_Poster                  Buhariwalla_OTNSymp2014_FactSheet

The fate of migrating Fraser River Coho salmon after fisheries interaction

Jacqueline Chapman, Carleton University

Recreational fisheries interactions may result in mortality or other ecologically relevant sub-lethal disturbances (e.g., delayed migration). For Pacific salmon, behavioural and physiological disturbances may result in failed migration, which is directly linked to individual fitness. In the upcoming field season, we propose to use gastrically inserted radio tags to assess the impact of angling and gillnet interactions on the migration success of Fraser River Coho. Treatment methods and telemetry array locations will be described to obtain feedback from OTN participants.

OTN and Marine Robotics

Adam Comeau, Dalhousie University

Water mass dynamics are critical to animal habitats and movements. Many marine animals are thermally conservative and it is energetically inef7icient to swim against currents. Direct measurement of hydrography is important for animal studies.

Estimates of phytoplankton and zooplankton concentrations can be used in ecological models while detection of tagged animals can help elucidate animal movements. Every level of the marine food web is open for exploration by gliders.

Decreasing oxygen concentrations on the Scotian Shelf negatively impact some animals, such as the Atlantic wolf7ish. OTN gliders, equipped with oxygen sensors, are capable of monitoring changes on multiple spatial scales.

Understanding tagging effects to facilitate stakeholder adoption of studies using electronic tags: a case study with adult Pacific salmon

Melissa Dick, Carleton University

The use of electronic tags is a popular technique to study wild fish. Sub lethal effects and tag-related mortality are concerns for any tagging study but are rarely estimated. This study will quantify the rates of tag retention and mortality for en route and pre-spawning adult sockeye salmon implanted with gastric or small external radio tags in the Harrison River, BC. The application of the findings will help to ensure that the techniques used are the best possible and to ultimately improve practices for welfare purposes. Given recent issues with stakeholders failing to fully embrace telemetry findings we suggest that inclusion of such tagging validations and refinements need to be considered as integral components of tracking studies.

Dick_OTNSymp2014_Poster                  Dick_OTNSymp2014_Summary

Arctic cod schools’ activity and interactions

Silviya Ivanova, University of Windsor

Arctic fisheries are expanding their ranges and moving into the high Arctic, a place where little research has been done on the trophic ecology of fish and mammal populations and even less has been communicated to the general public. My research will be comprised of a biological research component and a communications component, which will help bridge the gap between science and communications. Arctic cod is a species of special interest to the fisheries, and since it is considered to be a major link in the food web, it is essential to understand the species interactions with mammals and its activity related to boat traffic and ice conditions. In addition, the cod is especially important to the Inuit because it attracts beluga whales, seals and narwhals to the bay, which are their main source of food and income. Thus, the objective of the research would be to identify the occurrence and movement of Arctic cod schools during a full year and examine these against boat traffic/activity and the presence of cod predators. The communications component, a documentary film, will have the objective to communicate different aspects of the research, some of the issues the Canadian Arctic is facing, build understanding and promote collaboration between Inuit and researchers by exploring the complement and benefits of traditional ecological knowledge combined with high-tech research. The main underlying theme of the film will essentially focus on the research of Arctic cod. The main theme of the film will essentially focus on the process and challenges of researching in the Arctic.

Approaching the prey – competitor field: using the Vemco Mobile Transceiver to inform on the nature and spatiotemporal distribution of species interactions on the Eastern Scotian Shelf and in the southern Gulf of St. Lawrence

Damian Lidgard, Dalhousie University

The distribution of prey and inter-specific competition play a fundamental role in shaping the behaviour and spatiotemporal distribution of marine predators. Due to their wide-ranging nature, quantifying the prey/competitor field for marine predators is challenging. Here we provide a 4-year (2010-2013) summary of interactions between grey seals and potential prey/competitors collected through the use of acoustic (Vemco Mobile Transceiver, VMT) and GPS technology in two large marine ecosystems, the Eastern Scotian Shelf (ESS) and southern Gulf of St. Lawrence (sGSL), Canada. To date, 30 of 73 grey seals deployed with either a standard or Bluetooth-enabled GPS transmitter and VMT, have collected 2,422 fish detections from seven species of fish and one invertebrate, tagged with Vemco transmitters from nine different OTN projects. Of these, 13 VMTs have collected detections from 37 Atlantic cod, with one cod detected by three different VMTs across a two-year period. Other potential prey species detected were Atlantic salmon (11 individuals), snow crab (n = 3) and American eel (n = 2). Although there was substantial variation, seals tended to exhibit travelling behaviour during encounters with potential prey. Interactions between grey seals and possible competitors were also collected with detections recorded from tagged bluefin tuna (28 individuals), blue shark (n =5), porbeagle shark (n = 3) and Atlantic sturgeon (n =1). Seals tended to move slowly during these encounters suggesting seals might be foraging on a similar prey resource or targeting highly productive areas. Of interest, interactions between grey seals and bluefin tuna were particularly common accounting for 86% of detections collected by 20 of the 30 VMT tagged seals. These data highlight the successful use of acoustic and GPS technology for elucidating the prey-competitor field for large roving marine predators. In the coming year, another 5 Bluetooth units will be deployed on grey seals in the sGSL (in collaboration with DFO Quebec), in addition to standard units on 15 grey seals on Sable Island. In collaboration with Maritime Biologgers (Halifax), during 2014 we will deploy 5 accelerometers on grey seals to determine whether accelerometer data can assist with inferring predation events during seal-fish encounters.

Lidgard_OTNSymp2014_FactSheet

Atlantic sturgeon seasonality and spawning distribution in Minas Basin, inner Bay of Fundy, Canada

Laura Logan-Chesney, Acadia University

Since 2010, 114 Atlantic sturgeon have been tagged with V16 acoustic transmitters (Vemco Ltd., Halifax, Nova Scotia) and 16 Atlantic sturgeon have been tagged with archival tags (Wildlife Computers Ltd., Redmond, Washington) to study movement patterns, feeding behaviour, and post-bycatch survival in Minas Basin, Nova Scotia. Atlantic sturgeon were captured in intertidal brush weirs in Economy and Five Islands, Nova Scotia and by directed otter trawl in the Southern Bight of Minas Basin. Since 2007, 486 Atlantic sturgeon tissue samples (pelvic fin clips) have been collected for genetic analyses. Atlantic sturgeon population-specific movement patterns and behaviours such as timing of arrival, school fidelity, and depth preferences in Minas Passage and Minas Basin, Nova Scotia are being investigated using existing acoustic telemetry data. The natal spawning population of 92 acoustically tagged Atlantic sturgeon will be identified through genetic analyses of tissue samples. Spawning behaviour and viability of Atlantic sturgeon in Minas Basin is also being investigated. Six large female Atlantic sturgeon will be tagged with MiniPATs (Wildlife Computers Ltd., Redmond, Washington) and V16P acoustic transmitters (Vemco Ltd., Halifax, Nova Scotia) to examine upriver movements into four potential spawning rivers including the Kennetcook, Saint Croix, Shubenacadie and Stewiacke. Collaboration with Dr. Matt Litvak’s lab at Mount Allison University will enable sharing of acoustic telemetry data to determine linkages of tagged Atlantic sturgeon with the Saint John River, New Brunswick. Collaborations with Dr. Matt Balazik at Virginia Commonwealth University and Dr. Tim King at the USGS will allow for genetic identification of sampled Atlantic sturgeons’ natal spawning population. Network integration includes providing information on stock structure central to proper management, informing DFO and the OTN Ocean Governance group and comparison of Atlantic sturgeon movement and behaviour with other OTN researchers studying sturgeon species.

LoganChesney_OTNSymp2014_Poster

Understanding the consequences of recreational angling on the biology and movement of white sturgeon in the Lower Fraser River, British Columbia

Montana McLean, Dalhousie University

White sturgeon Acipenser transmontanus are the largest freshwater fish in North America and are found along the Pacific Coast from California to Alaska, with spawning populations distributed throughout three main watersheds: the Sacramento, Columbia, and Fraser Rivers. Like all sturgeon species, white sturgeon populations experienced reductions at the turn of the 20th century primarily from overfishing and many populations are considered endangered. The Lower Fraser River (LFR) white sturgeon are the target of a lucrative catch-and-release (C&R) fishery where some individuals can be captured up to six times in a season. Despite the cultural and economic importance of white sturgeon little is known about the potential post-release mortality and/or sub-lethal alterations in physiology and behaviour after C&R. The objectives of my research are to: 1) understand stress, 2) examine the effect of angling on stress and behaviour, and 3) examine seasonal movements and distributions of the LFR white sturgeon population. Additionally I will be testing if white sturgeon can be used as an acoustic tracking platform in areas of high flow to examine intra-and inter-specific interactions, for example sturgeon interactions with tagged Pacific salmon. Preliminary results from the 2014 field season will be presented, as well as an outline for upcoming research. In April 2014, 16 VR2Ws were deployed in the LFR to provide additional coverage in areas not already monitored by OTN or the province of B.C. These data will contribute to a number of existing projects, including ongoing Pacific salmon work led by OTN. Collaborations on this project stem from university, government, and non-government organizations, including the B.C. Ministry of Environment, the Department of Fisheries and Oceans, U.S. Fish and Wildlife, the International Centre for Sturgeon Studies and the Lower Fraser River Sturgeon Conservation Society, a not-for-profit environmental stewardship and research group. This multi-institutional partnership will form an important data sharing framework for a number of Pacific arena projects.

McLean_OTNSymp2014_FactSheet                 McLean_OTNSymp2014_Poster

Can partial estuarine area protection reduce the vulnerability of a highly mobile fishery species?

Taryn S. Murray, South African Institute for Aquatic Biodiversity

Acoustic telemetry was used to determine whether a partial estuarine protected area provides sufficient protection for highly mobile estuarine-dependent juvenile leervis Lichia amia (Carangidae) in the Goukou Estuary, South Africa. Seventeen individuals (233–608 mm fork length) were surgically equipped with coded acoustic transmitters and monitored for three months using an array of stationary acoustic receivers (n = 11, spaced 1.5 km apart). An additional receiver was placed offshore. Based on the proportion of time each tagged leervis spent at each receiver, it was determined that five individuals spent < 50% of their time (range: 0% to 37.6%) inside the EPA, while the remaining 12 individuals spent the majority of their time within the EPA (range: 59.2% to 95.2%). At least two individuals were recorded leaving the estuary, traveling to the adjacent Gouritz Estuary (approximately 50 km away) and Breede Estuary (approximately 60 km away). The preliminary findings of this study have shown that, despite the highly mobile nature of this species, partial estuarine protection is capable of reducing the vulnerability of juvenile leervis to capture in the local fishery.

Murray_OTNSymp2014_Poster

How do prey react to killer whale (Orcinus orca) presence? Quantifying the intimidation effects of killer whales in the eastern Canadian Arctic using predator-prey satellite telemetry

Natalie Reinhart, University of Manitoba

Apex predators have an important role in shaping ecological communities through cascading effects of top-down consumption. Yet predators can also affect prey population dynamics through intimidation effects that may disrupt prey behaviours important for fitness and survival. In the eastern Canadian Arctic (ECA), killer whales (Orcinus orca) occur seasonally and may be advancing into new regions in search of marine mammal prey as sea ice concentration decreases. Seals, narwhal (Monodon monoceros), beluga (Delphinapterus leucas) and bowhead whales (Balaena mysticetus) have all been observed to exhibit anti-predator behaviour in the presence of killer whales. Prey usually retreat to shallow water, or use areas with high sea ice concentration to avoid killer whales. In the present analysis, movements made by killer whales, narwhal and bowhead whales equipped with satellite transmitters overlap spatially and temporally in Prince Regent Inlet and the Gulf of Boothia in 2009 and 2013, providing an opportunity to quantify observed anti-predator behaviours. A preliminary analysis of narwhal and bowhead whale turning angles and movement speeds derived from satellite telemetry using Generalized Estimating Equations (GEE) is presented, whereby model parameter estimates allow for interpretation at the population level. Increases in predator-prey exposure may increase as killer whales expand their distributions and search for prey in the ECA. In light of predicted decreases in sea ice, an improved understanding of the effects of killer whale intimidation and consumption on prey population dynamics is imperative to predicting the cascading effects of killer whale predation to the entire ECA marine ecosystem.

Reinhart_OTNSymp2014_Factsheet                      Reinhart_OTNSymp2014_Poster

Influence of mussel farms on movements of the American lobster (Homarus americanus)

Émilie Simard, Institut des Sciences de la Mer (ISMER) & Institut Maurice-Lamontagne, Fisheries and Oceans Canada

A largely unstudied effect of off-bottom and suspended bivalve culture is how the the large amount of physical structure (ropes and anchor blocks) used in the practice affects benthic communities by modifying habitat characteristics, such as physical complexity, currents, sediment dynamics and sedimentation rates. Bivalve farming typically occurs above unvegetated soft bottom habitats and the addition of bivalve culture-related physical structures creates a more structurally complex type of habitat that may provide shelter to species that would not ordinarily be present in any abundance. In addition, mussel fall-off may represent the greatest input of organic matter to the seabed, a habitat in which such a food source is not generally found (i.e., compared to adjacent soft bottom habitats). A previous study done in a protected embayment showed that lobsters (Homarus americanus) are more abundant within mussel farms compare to adjacent areas and that their spatial distribution in mussel farms is influenced by both physical (anchor blocks as shelter) and trophic (enhanced feeding opportunities) effects. The artificial reef-like effects created by aquaculture structures could enhance the production of the surrounding (local) population or simply displace individuals.

The objective of this study is to better understand how off-shore mussel farms impact lobster aggregation and movement. To this end, lobster movements will be examined within and around an offshore mussel farm in îles de la Madeleine, eastern Canada.

Acoustic methods will be used to determine the affinity of lobster to a culture site and their movements within and around it. In short, 60 lobsters will be tracked within a mussel farm and at two sites outside of it (n = 20 lobsters site-1). At each site, a grid of VR2W fixed receivers (c.a. 1 km2) will be positioned on the seafloor by SCUBA divers, at 20 m depth. Lobsters movements inside and among the grids will be followed during summer 2014.

Simard_OTNSymp2014_Poster

Age and growth of Atlantic Sturgeon from the Saint John River, New Brunswick, Canada

Nathan Stewart, Acadia University

As a long-lived and late maturing species, Atlantic Sturgeon are susceptible to overharvest, making knowledge of their age and growth essential to sustainable management. The Saint John River, New Brunswick, and the St. Lawrence River, Quebec support the two remaining fisheries for Atlantic Sturgeon in Canada, however, the relationship between age and growth has not previously been modeled for the Saint John River stock. The von Bertalanffy growth model (VBGM) has been used to determine the relationship between age and growth for several spawning stocks of Atlantic Sturgeon along the east coast of North America. Pectoral fin spines have been the most commonly used structure for age determination of Atlantic Sturgeon due to accuracy and ease of collection. The VBGM of age and length for Atlantic Sturgeon in the Saint John River was obtained by aging pectoral fin spine sections collected from 233 individuals of known total length belonging to that stock. Most of the spine sections (84%) were aged by two of three readers to evaluate possible reader bias, which was assessed using the coefficient of variation (CV; readers 1 and 2: CV=6.3%; readers 1 and 3: CV=7.0%). Calculated VBGM parameters indicated males grew faster than females, but females attained a greater maximum length (males: K=0.05, L∞=247 cm; females: K=0.04, L∞=278 cm). The VBGM parameters obtained from combined sexes for the Saint John River population was medial for growth rate and maximum length compared to the Hudson and St. Lawrence Rivers (K=0.04, L∞=270 cm). OTN tagged and recaptured Atlantic Sturgeon both provided length information that supported this growth model and corroborated the genetically described link between the Minas Basin aggregation and the Saint John River population. This was a highly collaborative project with partners at Mount Allison University, DFO and industry (i.e., Acadia Sturgeon and Caviar Inc.). Network integration for the next year includes ongoing research with the University of Maine to establish growth parameters for the Kennebec River Atlantic Sturgeon population, and examination and comparison of age and growth characteristics of various sturgeon species including those studied inside OTN Canada projects.

Distribution and habitat use of adult and juvenile Atlantic sturgeon (Acipenser oxyrinchus Mitchill, 1815) from the Saint John River, NB, Canada

Andrew Taylor, Mount Allison University

We examined movement, activity, and seasonal distribution of Atlantic sturgeon from the Saint John River, NB, using a combination of ultrasonic and pop-up satellite archival tags and stable isotope analysis (SIA). Forty-four adult (2010-2012) and 8 juvenile (2013) Atlantic sturgeon were tagged with Vemco ultrasonic tags, and 14 adults were tagged with Wildlife Computers pop-up satellite archival tags (2011-2012). Adults were found primarily in lower river reaches over sandy substrate in the mid-water column during the summer. No daily behavioural patterns were detected in tagged adults. Five Atlantic sturgeon larvae were captured at the most upstream area where tagged fish were detected. The majority of tagged adults migrated out of the Saint John River in August and September of each year. Adults were distributed in a small area off the Saint John harbour throughout the winter months, and moved to inshore areas throughout the Bay of Fundy in the spring. Tags were primarily detected in the Bay of Fundy, but have been detected as far north as southeast Newfoundland. Three adults returned to the river in 2013, 2 that were tagged in 2010 migrated to potential upstream spawning locations and 1 tagged in 2011 remained in river reaches below the salt/fresh interface. SIA indicated that adult Atlantic sturgeon switch to a marine diet supporting the hypothesis that adults do not feed in the river. Tagged juvenile Atlantic sturgeon frequently moved between specific areas in the Kennebecasis and Saint John River. A similar isotope signature between juvenile Atlantic sturgeon and similar-sized adult shortnose sturgeon (A. brevirostrum) suggests the potential for competition between these two sturgeons in the Saint John River. Progress made within the Saint John River has provided a foundation for expansion throughout the Atlantic region. We will be extending our tagging program on juveniles in the Saint John River and begin tagging adults in the Miramichi and Petitcodiac Rivers in collaboration with two First Nation groups. Integration through the Ocean Tracking Network has provided opportunity for extensive data collection, and is crucial for determining the extent of movement of Atlantic sturgeon adults throughout the Atlantic region.

Taylor_OTNSymp2014_FactSheet

State-Space Modelling Frameworks: Behaviour, Capabilities, and Limitations When Applied to Animal Movement Data

Kim Whoriskey, Dalhousie University

Non-Gaussian errors are inherent with Argos satellite telemetry data, prompting the development of state-space models capable of simultaneously incorporating information on the movement process and on the accuracy of Argos observations when estimating true (unobserved) animal tracks. Our objectives are twofold. First, we formally compare two state-space models that fundamentally differ in their process equations, as one estimates locations over continuous time (CTCRW) and the other in discrete time by incorporating a mode of time regularization (DCRW). We find that although the CTCRW typically exhibits a smoothing effect while the DCRW estimated track has a more jagged appearance, overall both models have similar capabilities. Second, we consider these results when utilizing state space models to make comparisons between offshore (Sable Island, NS) and onshore (Hay Island, NS) grey seal (Halichoerus grypus) populations; these analyses provide important information on the relatability of the two populations, as well as suggest refinements to the state space model formulation with respect to model behaviour, capabilities, and limitations for application to marine animal movement data.

Whoriskey_OTNSymp2014_Poster

Simulating the decline of Atlantic salmon populations

Rui Zhang, Dalhousie University

North American Atlantic salmon populations experienced a dramatic decline in the early 1990s and have persisted at a low abundance since then. Changes in climate patterns and multiple ecosystem conditions have likely contributed to this decline. In this study, we use a Leslie matrix population model to examine variations of Atlantic salmon abundance from 1971 to 2011. We assess the model performance by comparing model results against estimated abundances from the 2013 ICES Report of the Working Group on North Atlantic Salmon. In a parameter sensitivity analysis we show that among parameters related with the marine environment, the survival rates during the smoltification year and during the first year at sea have the greatest influence on population variation. In further studies our goal is to assess how physical (e.g. circulation, temperature, nutrient flux) and ecosystem conditions (e.g. phytoplankton and zooplankton abundance) affect salmon survival in the early marine stages and the dynamics of the salmon population as a whole.​​

Assessment of marine animal tag data for ocean observations

Karl Lagman1, Katja Fennel1, Damian Lidgard1, Don Bowen2 Richard Davis1, John Cullen1, Sara Iverson(1Dalhousie University, 2Bedford Institute for Oceanography)

Lagmen et al._OTNSymp2014_FactSheet