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Fin whale 20 Hz calls were detected, localized, and tracked using a 10 km aperture network of three acoustic receivers deployed for 11 months in a Pacific Canadian fjord system. The area has been historically important for fin whales and is located along a route that tankers will begin using in 2024. A total of 6712 calls were localized, and trajectories were fitted for 55 acoustic tracks. Fin whale tracks occurred throughout the monitoring site. Call activity peaked in September and was low during winter months. Swimming characteristics varied significantly between day- and nighttime: at night, whales swam faster (7.1 vs 4.0 km/h median, +75.2%), which resulted in longer (+34.7%), less predictable (-70.6%) tracks as compared to daylight hours. Call frequencies varied between 16 and 32 Hz. Beside stereotypical song frequencies, fin whales also used irregular frequency components, which contributed the majority of calls in the summer but did not occur in the winter. The results suggest that the area is primarily used as a summer feeding ground, where fin whales follow a diel behavioral cycle. The observed activity patterns will aid in the assessment of strike risk and harassment mitigation and provide a baseline to document behavioral change.

Funding: This research was supported by a Mitacs Accelerate Internship (IT21479); the Save Our Seas Foundation; Willow Grove Foundation; Donner Canadian Foundation; Tides Canada; LUSH Charity Pot; private donations to North Coast Cetacean Society; Fisheries and Oceans Canada; and the Canada Nature Fund for Aquatic Species at Risk (CANAFSAR 2019-2021). Fin whales (Balaenoptera physalus) are widely considered an offshore and oceanic species, but certain populations also use coastal areas and semi-enclosed seas. Based upon fifteen years of study, we report that Canadian Pacific fin whales (B. p. velifera) have returned to the Kitimat Fjord System (KFS) in the Great Bear Rainforest, and have established a seasonally resident population in its intracoastal waters. This is the only fjord system along this coast or elsewhere in which fin whales are known to occur regularly with strong site fidelity. The KFS was also the only Canadian Pacific fjord system in which fin whales were commonly found and killed during commercial whaling, pointing to its long-term importance. Traditional knowledge, whaling records, and citizen science databases suggest that fin whales were extirpated from this area prior to their return in 2005-2006. Visual surveys and mark-recapture analysis documented their repopulation of the area, with 100-120 whales using the fjord system in recent years, as well as the establishment of a seasonally resident population with annual return rates higher than 70%. Line transect surveys identified the central and outer channels of the KFS as the primary fin whale habitat, with the greatest densities occurring in Squally Channel and Caamano Sound. Fin whales were observed in the KFS in most months of the year. Vessel- and shore-based surveys (27,311 km and 6,572 hours of effort, respectively) indicated regular fin whale presence (2,542 detections), including mother-calf pairs, from June to October and peak abundance in late August-early September. Seasonal patterns were variable year-to-year, and several lines of evidence indicated that fin whales arrived and departed from the KFS repeatedly throughout the summer and fall. Additionally, we report on the population's social network and morphometrics. These findings offer insights into the dynamics of population recovery in an area where several marine shipping projects are proposed. The fin whales of the Great Bear Rainforest represent a rare exception to general patterns in this species' natural history, and we highlight the importance of their conservation. Publisher PDF

Localization and tracking of vocalizing marine mammals are powerful tools for understanding and mitigating the impacts of anthropogenic stressors such as vessel noise on habitat use of cetaceans. A large-aperture hydrophone network has been installed in the Kitimat Fjord System, an ecologically, culturally, and economically valued marine environment in northern British Columbia, Canada. This network consists of four synchronized bottom-mounted hydrophones that permanently record and radio-transmit data to a land-based laboratory. An automated system has been developed which includes routines to localize transient bio-acoustic signals from three or more streaming hydrophones in near real-time. These routines comprise the correlation of hydrophone signals, the construction of a time lag model, and signal localization and error estimation from a spatial likelihood surface. The localization method was tested experimentally and subsequently applied to vocalizations from humpback whales, fin whales, and killer whales. Refractive and reflective sound propagation effects in the confined fjords are assessed using ray tracing propagation models. Automated localization results are compared to ground-truth data and shown to provide good accuracy.

Abstract ContextThe shore-based survey is a common, non-invasive, and low-cost method in marine mammal science, but its scientific applications are currently limited. Such studies typically target populations whose distributions are not random with respect to nearshore sites and involve repeated scans of the same area from single, stationary platforms. These circumstances prohibit the use of classic distance sampling techniques for estimating animal densities or distributions, particularly the derivation of a detection function that describes the probability of detecting targets at various distances from the observer. AimsHere, we present a technique for estimating land-based detection functions, as well as quantifying uncertainty in their parameterisation, on the basis of the range-specific variability of observations from one scan to the next. MethodsThis Bayesian technique uses Monte Carlo simulation to determine the likelihood of thousands of candidate detection functions, then conducts weighted sampling to generate a posterior distribution estimate of the detection function parameterisation. We tested the approach with both archival and artificial datasets built from known detection functions that reflect whale and porpoise detectability. Key resultsWhen the base distribution of targets was random, the whale detection function was estimated without error (i.e. the difference of the median of the posterior and the true value was 0.00), and the porpoise detection function was estimated with an error equal to 4.23% of the true value. When the target base distribution was non-random, estimation error remained low (2.57% for targets concentrated offshore, 1.14% when associated with nearshore habitats). When applied to field observations of humpback whales and Dall’s porpoises from a land-based study in northern British Columbia, Canada, this technique yielded credible results for humpback whales, but appeared to underestimate the detectability of Dall’s porpoises. ConclusionThe findings presented here indicate that this approach to detection function estimation is appropriate for long-running surveys in which scan regularity is high and the focus is on large, slow-moving, low herd-size, and easily detectable species. ImplicationsThe derivation of a detection function is a critical step in density estimation. The methodology presented here empowers land-based studies to contribute to quantitative monitoring and assessment of marine mammal populations in coastal habitats.

The effects of climate change on marine ecosystems are accelerating. Identifying and protecting areas of the ocean where conditions are most stable may provide another tool for adaptation to climate change. To date, research on potential marine climate refugia has focused on tropical systems, particularly coral reefs. We examined a northeast Pacific temperate region – Canada’s Pacific – toidentify areas where physical conditions are stable or changing slowly. We analyzed the rate and consistency of change for climatic variables where recent historical data were available for the whole region, which included sea surface temperature, sea surface height, and chlorophyll a . We found that some regions have been relatively stable with respect to these variables. In discussions with experts in the oceanography of this region, we identified general characteristics that may limit exposure to climate change. We used climate models for sea surface temperature and sea surface height to assess projected future changes. Climate projections indicate that large or moderate changes will occur throughout virtually the entire area and that small changes will occur in only limited portions of the coast. Combining past and future areas of stability in all three examined variables to identify potential climate refugia indicates that only 0.27% of the study region may be insulated from current and projected future change. A greater proportion of the study region (11%) was stable in two of the three variables. Some of these areas overlap with oceanographic features that are thought to limit climate change exposure. This approach allowed for an assessment of potential climate refugia that could also have applications in other regions and systems, but revealed that there are unlikely to be many areas unaffected by climate change.

In the north-eastern Pacific, fin whales (Balaenoptara physalus) are typically found and studied in open waters near or seaward of the continental shelf. The Kitimat fjord system is a network of sounds and channels along the coast of British Columbia, Canada, and is one of only a few known fin whale habitats within confined coastal waters. In 2018, we deployed a network of hydrophones in Squally Channel, a proposed shipping lane located at the center of the fjord system, to monitor and track fin whales for a period of 2 years. The work is part of an effort to mitigate anthropogenic stressors on whales in the traditional territory of the Gitga'at First Nation. Here, we present spatial-temporal habitat use by fin whales in this confined inshore ecosystem based on more than 30 000 call detections and 7000 source localizations. Two distinct call types were recorded, a 20 Hz and a 40 Hz pulse, with distinctly different seasonal and diel trends. About 100 individual tracks were reconstructed from 20 Hz call sequences and analyzed for calling characteristics and movement patterns. A better understanding of fin whale habitat in the north-east Pacific is of special importance in light of an active discussion about the conservation status of this large baleen whale in Canadian waters.

A partnership of the Gitga'at First Nation, WWF-Canada and the North Coast Cetacean Society has installed a long baseline hydrophone array in Squally Channel; a culturally, ecologically, and economically important marine environment in northern British Columbia (BC), Canada. The array consists of four synchronized bottom-mounted hydrophones that permanently record and radio-transmit data to a land-based laboratory in real-time. The array covers an area of approximately 200 km2 to realize long-term and wide-range monitoring of marine mammals. To allow for efficient data analysis, automated detectors for cetacean vocalizations have been developed in collaboration with the University of Victoria. The detection performance has been tested using manually annotated data. We present an overview of the detectors for orca and humpback whales, and their computational and analytic performance as a function of signal-to-noise ratio. The ability to adapt to different ocean environments and target species is demonstrated by applying the detectors to 100 days of archival acoustic data recorded at two different places along the BC coast. Data recorded during pilot studies in 2017 from Squally Channel (approximately 30 days) is used to provide an overview of cetacean vocalization detections. Finally, we show acoustic activity variations and trends based on environmental factors.

Dual-platform studies in confined marine habitats can contribute to the calibration of passive acoustic data for purposes of density estimation. We established a long baseline hydrophone array in northern coastal British Columbia, Canada, that consists of four synchronized, bottom-mounted, continuously recording hydrophones. Automated detectors have been developed for vocalizations of humpback whales, orcas, and fin whales. Visual surveys are conducted from an observation platform overseeing the same area of approximately 200 sq. km. Here we compare humpback whale detections between the visual and acoustic platforms for 78 days of surveys in 2018. Two call types were analyzed: bubble net feeding calls and miscellaneous other. Acoustic surveys yielded higher detection rates (15x) of bubble net feeding groups than visual surveys, but visual detection rates of humpback whales engaged in other behaviors were twice that of acoustic surveys. When summarizing data into 24-hour periods, we found strong correlations between visual and acoustic detection rates for both call types. These correlations were strongest when all visual detections were included, and weakest when we excluded distant sightings from our dataset. These preliminary results are an encouraging first step in the derivation of call rates and the estimation of local species densities using passive acoustics.

Ecosystem-based approaches to fisheries management to date have lacked a quantitative spatial understanding of habitat impacts from fishing. Understanding such ecological impacts in part requires knowledge of benthic structure and sensitivity. We compared two approaches to calculate and map spatially explicit habitat impacts for twelve different fisheries in 21 broad benthic classes in Canada's Pacific. By fishery, bottom trawling had the highest sum impact score across benthic classes, and bottom trawl and bottom longline generally scored highest per unit area. Soft shelf, which was the most extensively fished benthic class (33,373 km2 of a total 454,183 km2 study area), had the highest cumulative impact score, followed by the slope benthic classes (16,315 km2). Canyons and slope benthic classes had the highest impact scores per unit area. We recommend our approach as one that facilitates a regional understanding of benthic habitat impact by individual fisheries, as well as of cumulative impact for all bottom and demersal fishing activities. This assessment also highlights the regional paucity of habitat data required for more detailed analyses. Such habitat impact assessments have utility in informing fisheries assessments for eco-certification schemes, and in the mitigation of benthic habitat impacts through marine spatial planning efforts.

The rapidly progressing field of cumulative effects mapping is highly dependent on data quality and quantity. Availability of spatial data on the location of human activities on or affecting the ocean has substantially improved our understanding of potential cumulative effects. However, datasets for some activities remain poor and increased access to current, high resolution data are needed. Here we present an updated analysis of potential cumulative effects in Canada’s Pacific marine waters. New, updated datasets and methodological improvements over the previous analysis were completed, including a new index for land-based effects on marine habitats, updated habitat classes and a modified treatment of vulnerability scores. The results show increased potential cumulative effects for the region. Fishing remains the biggest overall impact amongst marine activities, while land-based activities have the highest impact per unit area in affected ocean areas. Intertidal areas were the most affected habitat per unit area, while pelagic habitats had the highest total cumulative effect score. Regular updates of cumulative effects assessments will make them more useful for management, but these require regularly updated, high resolution datasets across all activity types, and automated, well-documented procedures to make them accessible to managers and policy-makers.

Much knowledge is emerging about the past and potential effects of climate change on the unique and complex marine ecosystems of Canada's Pacific, including variations in the resilience, sensitivities, responsiveness, and non-stationarity of the biota. Such knowledge, however, is rarely synthesized or summarized with any overall integrated analyses that could guide the development of proactive planning for the effects of climate change. Regional and local planning of climate adaptation strategies, for example, requires an examination of ecological sensitivities and vulnerabilities at relevant spatial resolutions. We developed an illustrative example of a habitat-based ecological vulnerability assessment for the whole of Canada's Pacific marine area using existing spatial information from this region and from the California Current ecosystem. Potential climate impacts were calculated as the product of estimated exposure (E) of habitats to multiple dimensions of changing climate variables and expert-derived sensitivity (S) ratings of those habitats to changes in those climate variables. Vulnerability was then derived as the product of the estimated potential climate impacts in a location and the estimated cumulative impacts (CI) of non-climate stressors there, which we considered to be an inverse proxy of the adaptive capacity (AC) of the biota in those habitats. We found considerable spatial variability of potential climate impacts and vulnerability on the scales of the 12 Ecosections of Canada's Pacific, 25 habitat categories, and at finer scales. We produced maps of ecological vulnerability to climate change as an example output for use in spatially-oriented adaptation planning. Our initial assessment indicated that the Strait of Georgia in particular followed by Queen Charlotte Strait, Juan de Fuca Strait, Vancouver Island Shelf, and Johnstone Strait have relatively high vulnerabilities to climate change, in part due to concentrations of local stressors there. On a coast wide basis the habitats that were indicated as most vulnerable are shallow rocky reefs, seagrass habitats, kelp habitats, and deep rocky reefs. This approach for mapping vulnerability to climate change could be improved with finer scale climate data, additional climate variables, and stressor-habitat sensitivity estimates derived specifically for this system. We provide a stepwise manual for policy-makers, managers, or other practitioners to map ecological vulnerability to climate change in other marine settings.

The marine life of Canada’s Pacific marine ecosystems, adjacent to the province of British Columbia, may be relatively responsive to rapid oceanographic and environmental change associated with global climate change due to uniquely evolved plasticities and resiliencies as well as particular sensitivities and vulnerabilities, given this dynamic and highly textured natural setting. These marine ecosystems feature complex interfaces of coastal geomorphology, climate, and oceanography, including a dynamic oceanographic and ecological transition zone formed by the divergence of the North Pacific Current into the Alaskan coastal current and the California Current, and by currents transporting warm tropical waters from the south. Despite long-term warming in the region, sea surface temperatures in Canada’s Pacific have been anomalously cool since 2007 with La Nina-type conditions prevailing as we enter a cool phase of the Pacific Decadal Oscillation, possibly masking future warming. When warmer El Nino conditions prevail, many southern species invade, strongly impacting local species and reorganizing biological communities. Acidification and deoxygenation are anomalously high in the region due to the weakening ventilation of subsurface waters resulting from increased stratification. A broad spectrum of biological responses to these changes are expected. Non-climate anthropogenic stressors affect the capacity of biota to adapt to climate changes. It will be challenging to forecast the responses of particular species, and to map climate vulnerabilities accurately enough to help prioritize and guide adaptation planning. It will be more challenging to develop forecasts that account for indirect effects within biological communities and the intricate and apparently non-deterministic behaviours of highly complex and variable marine ecosystems, such as those of Canada’s Pacific. We recommend and outline national and regional climate assessments in Canada and adaptation planning and implementation including integrated coastal management and marine spatial planning and management.

Real-time localization and tracking of vocalizing marine mammals is a powerful tool to a) mitigate the risk of ship strikes and disturbance of the animals as well as b) to understand the impact of anthropogenic noise on habitat use of cetaceans. A long baseline hydrophone array has been installed in Squally Channel, a culturally, ecologically, and economically important marine environment in northern British Columbia, Canada. The array consists of four synchronized bottom-mounted hydrophones that permanently record and radio-transmit data to a land-based laboratory. Automated analysis tools have been developed to detect and localize transient bioacoustic signals from three or more hydrophones in real-time. They comprise the correlation of hydrophone signals, the construction of a replica surface using acoustic propagation models, and signal localization from a spatial likelihood surface. An overview of the localization method is presented. We assess spatial localization precision and discuss random and systematic sources of error stemming from the signal type and quality, bathymetry, sound speed profile, as well as the spatial distribution of hydrophones and acoustic sources. Simulation results are compared to field measurements. Based on our findings, challenges and opportunities associated with localization using long baseline arrays in coastal environments are discussed.

Monitoring the aquatic soundscape provides critical information about marine mammal habitat use. It is essential for developing mitigation strategies for areas with expanding marine shipping and industrial activity. A long baseline hydrophone array has been installed in Squally Channel, a culturally, ecologically, and economically important marine environment in northern British Columbia, Canada. The array consists of four synchronized bottom-mounted hydrophones that permanently record and radio-transmit data to a land-based laboratory in real-time. The acoustic monitoring is supplemented with a land-based visual observatory that oversees the same area of approximately 200 km2. Automated detectors have been developed for vocalizations of humpback whales, orcas, and fin whales. Acoustic data and visual surveys were analyzed for a period of more than 100 days between 2017 and 2018. We present an overview of the acoustic detection functions and their performance by call type and summarize visual survey procedures. Cetacean activity derived from automated acoustic detections and visual observations is analyzed. Finally, acoustic and visual survey methods are compared to assess a) the fraction to which different species are acoustically active while in the area, and b) the effectiveness of both acoustic and visual monitoring efforts for the purpose of cetacean monitoring.

Analysis of cumulative human impacts in the marine environment is still in its infancy but developing rapidly. In this study, existing approaches were expanded upon, aiming for a realistic consideration of cumulative impacts at a regional scale. Thirty-eight human activities were considered, with each broken down according to stressor types and a range of spatial influences. To add to the policy relevance, existing stressors within and outside of conservation areas were compared. Results indicate the entire continental shelf of Canada's Pacific marine waters is affected by multiple human activities at some level. Commercial fishing, land-based activities and marine transportation accounted for 57.0%, 19.1%, and 17.7% of total cumulative impacts, respectively. Surprisingly, most areas with conservation designations contained higher impact scores than the mean values of their corresponding ecoregions. Despite recent advances in mapping cumulative impacts, many limitations remain. Nonetheless, preliminary analyses such as these can provide information relevant to precautionary management and conservation efforts.

The current regime of fisheries management and the prospects for attaining a more locally oriented, collaborative system of fisheries management in Diani-Chale, Kenya are examined. At present fisheries management in Diani-Chale is characterized by diminished government capacity for regulation, weakened local institutions, and little ability to exert control over the use of fisheries. Local level management requires the development and use of local institutions that can govern the use of fishery resources. The fish landing sites used by fishers and their associated fishing grounds were identified to be at the appropriate level for resolving fishery management issues. A more formal role for these entities, the clarification of fishing ground tenure and access rights, and support for the development and enforcement of local fishing rules can further local management. The socioeconomic condition of fishers, their fear of losing landing sites, and the continued perception of the imposition of a marine reserve ...