Fig 1 - uploaded by Marla M Holt
Content may be subject to copyright.
Representative example of echolocation clicks of the tagged whale (black arrow) and 50 kHz navigational sonar emitted by boats (red arrow) recorded by the tag. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)
Source publication
Vessel traffic is prevalent throughout marine environments. However, we often have a limited understanding of vessel impacts on marine wildlife, particularly cetaceans, due to challenges of studying fully-aquatic species. To investigate vessel and acoustic effects on cetacean foraging behavior, we attached suction-cup sound and movement tags to end...
Context in source publication
Context 1
... sounds in the 10-65 kHz band, and (2) all other vessel and sound variables. The dives were pooled across 17 tag deployments and 15 individuals (two individuals were tagged twice but in separate years, Table 2). Echosounder signals were detected during 52% (60/115) of these dives and the vast majority occurred at a center frequency of 50 kHz (Fig. 1), coinciding with the center frequency of killer whale outgoing echolocation clicks ( Au et al., 2004). Noise level ranged between 88.3 and 138.9 dB re: 1 μPa (10-65 kHz), median vessel speed ranged between 0 (stationary) and 3 (5-6 knots), and mean vessel distance ranged between 21 and 852 m. We found that vessel speed (χ 2 = 6.62, df ...
Similar publications
Banderas Bay, Mexico is an important breeding and transit area for the North Pacific humpback whale (Megaptera novaeangliae) population. In this paper we estimated relative abundance (RA = number of whales/hours of navigation) as a proxy to assess population temporary patterns in the area. We analyzed data from 14 breeding seasons (2004-2017), coll...
O turismo marítimo, especialmente a observação de baleias, tem se destacado no âmbito do Ecoturismo, oferecendo não apenas sensibilização ambiental, mas também um significativo impacto econômico. Estima-se que 14 milhões de pessoas participem dessa atividade anualmente, com vendas globais gerando bilhões de dólares. No Brasil, a Praia do Forte se t...
The study and conservation of cetaceans benefit from systematic studies and non-systematic records about sightings and strandings. However, iEcology (internet ecology) was critical for numerous ecological studies and should be in the toolkit of cetacean ecologists. We hypothesize that iEcology is irreplaceable to obtain diversity data about cetacea...
Whale-watching tourism generates high-income seasonal livelihoods in coastal communities on the Mexican Pacific Coast; however, this sector is at risk from accelerated global changes. We evaluated the responses of a collaboration of tourism networks regarding the impacts COVID-19 using a longitudinal social network approach. We used a two-wave snow...
The growing concerns about the negative effects caused by whale watching on wild cetacean populations are evincing the need to measure whale watching effort more precisely. The current alternatives do not provide sufficient information or imply time-consuming and staff-intensive tasks that limit their effectiveness to establish the maximum carrying...
Citations
... Studies of southern resident killer whales carrying suction cupped sound and movement tags have found the probability of killer whales capturing prey increases as salmon abundance increases, but is negatively affected by the movements and noise of nearby vessels [62,63]. Vessel noise can mask communication between pod members and interfere with foraging and navigation [64,65]-while the physical presence of vessels can reduce the foraging effort of resident killer whales [63,66]. ...
Differences in the availability of prey may explain the low numbers of southern resident killer whales and the increase in northern resident killer whales in British Columbia and Washington State. However, in-situ data on the availability of their preferred prey (Chinook salmon, Oncorhynchus tshawytscha) in the core feeding areas used by these two populations of fish-eating killer whales have been lacking to test this hypothesis. We used multi-frequency echosounders (38, 70, 120, and 200 kHz) to estimate densities of adult Chinook (age-4+, > 81 cm) within 16 hot-spot feeding areas used by resident killer whales during summer 2020 in the Salish Sea and North Island Waters. We found Chinook were generally concentrated within 50 m from the bottom in the deep waters, and tended to be absent near the surface in the shallow waters (< 50 m). In general, the densities of Chinook we encountered were highest as the fish entered the Salish Sea (from Swiftsure Bank in the south) and Johnstone Strait (from Queen Charlotte Strait to the north)—and declined as fish migrated eastward along the shoreline of Vancouver Island. Median densities of Chinook for all sampled areas combined were 0.4 ind.·1000 m⁻² in northern resident foraging areas, and 0.9 ind.·1000 m⁻² in southern resident killer whale areas (p < 0.05, Mann–Whitney U test). Thus, Chinook salmon were twice as prevalent within the hot-spot feeding areas of southern versus northern resident killer whales. This implies that southern resident killer whales have greater access to Chinook salmon compared to northern residents during summer—and that any food shortage southern residents may be encountering is occurring at other times of year, or elsewhere in their range.
... The population was first listed as Threatened in Canada in 1999 and then Endangered in 2001 (Baird, 2001), while in the U.S., SRKWs were listed as Endangered under the Endangered Species Act in 2005. Threats to the long-term viability of SRKWs include reduced quantity and quality of prey, exposure to persistent organic pollutants, disturbance from vessels, and small population size (Krahn et al., 2004;2009;Ford et al., 2010;Wasser et al., 2017;Hanson et al., 2021;Holt et al., 2021;Kardos et al., 2023). ...
Here we update U.S. West Coast Biologically Important Areas (BIAs) that were published in 2015 using new data and approaches. Additionally, BIAs were delineated for two species that were not delineated in the 2015 BIAs: fin whales and Southern Resident killer whales (SRKW). While harbor porpoise BIAs remained the same, substantial changes were made for other species including identifying both larger overall areas (parent BIAs) and smaller core areas (child BIAs). For blue, fin, and humpback whales we identified, delineated, and scored BIAs using the overlap between the distribution and relative density from three data sources, leveraging the strengths and weaknesses of these approaches: 1) habitat density models based on Southwest Fisheries Science Center (SWFSC) line-transect data from systematic ship surveys conducted through 2018, 2) satellite tag data from deployments conducted by three research groups, and 3) sightings of feeding behavior from non-systematic effort mostly associated with small-boat surveys for photo-identification conducted by Cascadia Research Collective. While the previous BIAs were based solely on a more subjective assignment from only the small boat sightings, here we incorporate the other two data sources and use a more rigorous, quantitative approach to identify higher density areas and integrate the data types. This resulted in larger, better-supported, objective BIAs compared to the previous effort. Our methods are also more consistent with the delineation of BIAs in other regions. For SRKWs, the parent BIA was based on a modification of the Critical Habitat boundaries defined by the National Oceanographic and Atmospheric Administration (NOAA) and the Department of Fisheries and Oceans (DFO) Canada; a core BIA highlighting areas of intensified use was identified using both NOAA’s Critical Habitat and kernel density analyses of satellite tag data. Gray whale BIAs were re-evaluated for the migratory corridor of Eastern North Pacific gray whales, for Pacific Coast Feeding Group feeding areas, and for gray whales that feed regularly in Puget Sound.
... There is increasing evidence of the impact of anthropogenic sound exposure on marine mammal hearing loss [37,39,42,81], behavioral changes (see [127] for a review), impaired communication [128,129], and reduced foraging efficiency [130,131]. Robust welfare-monitoring protocols for marine mammals in managed care have yet to regularly incorporate acoustic monitoring into their recommendations. We provide evidence that technological advancements have made applied tools for acoustic welfare monitoring accessible. ...
Research evaluating marine mammal welfare and opportunities for advancements in the care of species housed in a professional facility have rapidly increased in the past decade. While topics, such as comfortable housing, adequate social opportunities, stimulating enrichment, and a high standard of medical care, have continued to receive attention from managers and scientists, there is a lack of established acoustic consideration for monitoring the welfare of these animals. Marine mammals rely on sound production and reception for navigation and communication. Regulations governing anthropogenic sound production in our oceans have been put in place by many countries around the world, largely based on the results of research with managed and trained animals, due to the potential negative impacts that unrestricted noise can have on marine mammals. However, there has not been an established best practice for the acoustic welfare monitoring of marine mammals in professional care. By monitoring animal hearing and vocal behavior, a more holistic view of animal welfare can be achieved through the early detection of anthropogenic sound sources, the acoustic behavior of the animals, and even the features of the calls. In this review, the practice of monitoring cetacean acoustic welfare through behavioral hearing tests and auditory evoked potentials (AEPs), passive acoustic monitoring, such as the Welfare Acoustic Monitoring System (WAMS), as well as ideas for using advanced technologies for utilizing vocal biomarkers of health are introduced and reviewed as opportunities for integration into marine mammal welfare plans.
... Previous studies specific to the SRKW have shown that vessel traffic disrupts foraging behavior (Lusseau et al. 2009), that the probability of successful prey capture decreases with increasing vessel speed (Holt et al. 2021), and that high noise levels reduce their probability of foraging in the first place (Williams et al. 2021). Modeling work connecting the ECHO slowdown with SRKW bioenergetics predicted that the voluntary slowdown led to a 22% reduction in "potential lost foraging time" (Joy et al. 2019); this value changed to a 40% reduction in potential lost foraging time when the model was set to a 100% participation rate of vessels travelling under 11 knots. ...
... To date, conservation efforts for North Pacific killer whales and marine mammals more broadly 70,71 , have largely, and often successfully, focused on mitigating extrinsic environmental threats. Protection from direct harm (capture and intentional killing) and continuing efforts to address extrinsic threats such as prey abundance 72 , toxic pollution 24 and vessel traffic [52][53][54] , have contributed to sustained population growth of many (but not all 73 ) North Pacific killer whale populations since the 1970s 51,58 . While these efforts have also reduced environmental threats to the SRKW, they have not resulted in the sustained population growth observed in many other North Pacific populations 59 . ...
Understanding the factors that cause endangered populations to either grow or decline is crucial for preserving biodiversity. Conservation efforts often address extrinsic threats, such as environmental degradation and overexploitation, that can limit the recovery of endangered populations. Genetic factors such as inbreeding depression can also affect population dynamics but these effects are rarely measured in the wild and thus often neglected in conservation efforts. Here we show that inbreeding depression strongly influences the population dynamics of an endangered killer whale population, despite genomic signatures of purging of deleterious alleles via natural selection. We find that the ‘Southern Residents’, which are currently endangered despite nearly 50 years of conservation efforts, exhibit strong inbreeding depression for survival. Our population models suggest that this inbreeding depression limits population growth and predict further decline if the population remains genetically isolated and typical environmental conditions continue. The Southern Residents also had more inferred homozygous deleterious alleles than three other, growing, populations, further suggesting that inbreeding depression affects population fitness. These results demonstrate that inbreeding depression can substantially limit the recovery of endangered populations. Conservation actions focused only on extrinsic threats may therefore fail to account for key intrinsic genetic factors that also limit population growth.
... We were unable to use available salmon abundance indices due to 1) spatial incongruency between the salmon stocks/regions where these abundance data were sampled and the prey consumed by NRKW and SRKW during our study period and location, 2) issues with sporadic coverage and the degree to which effort had been accounted for in some of the existing salmon indices, and 3) reliability issues with applying widely used salmon data from the Albion Test Fishery situated on the Fraser River (e.g., Ayres et al. 2012;Ford et al. 2016;Wasser et al. 2017;Holt et al. 2021a), because of uncertainty in the proportions of salmon taking one of two possible paths around Vancouver Island, BC to return to the Fraser River ( Figure 1). Therefore, the week-year random effect allowed us to account as best as possible for temporal variability in salmon abundance and other environmental factors on a weekly basis that might be responsible for the differences in foraging patterns we measured within and between populations. ...
... Therefore, any impact from the tagging vessel may underscore the general sensitivity of lactating females to nearby vessels (e.g., Holt et al. 2021b). Given the number of vessels frequently in their proximity (Giles 2014;Holt et al. 2021aHolt et al. , 2021b, SRKW females with vulnerable calves may have been routinely foregoing foraging opportunities during the study period. Whether this loss of opportunity to consume prey is offset by food sharing from other individuals in the pod or translates to energy loss remains unknown. ...
... The nuances of migration paths taken are directly related to accurately estimating salmon availability for each population, yet data at this fine-scale spatiotemporal resolution are not currently available. We suggest that future research should elucidate the complex relationships between 1) environmental factors including location, prey distributions, and availability, 2) the behavioral context of the animal at the time of tagging, and 3) differential population-level impacts of anthropogenic pressures, including impacts from tagging and vessel presence, on foraging behavior (e.g., Holt et al. 2021aHolt et al. , 2021b. Furthermore, it is important to determine whether population differences in individual foraging behavior persist throughout space and time, and whether individual roles are flexible within populations. ...
In cooperative species, human-induced rapid environmental change may threaten cost–benefit tradeoffs of group behavioral strategies that evolved in past environments. Capacity for behavioral flexibility can increase population viability in novel environments. Whether the partitioning of individual responsibilities within social groups is fixed or flexible across populations is poorly understood, despite its relevance for predicting responses to global change at the population and species levels and designing successful conservation programs. We leveraged bio-logging data from two populations of fish-eating killer whales (Orcinus orca) to quantify patterns of fine-scale foraging movements and their relationships with demography. We reveal striking interpopulation differences in patterns of individual foraging behavior. Females from the endangered Southern Resident (SRKW) population captured less prey and spent less time pursuing prey than SRKW males or Northern Resident (NRKW) females, whereas NRKW females captured more prey than NRKW males. The presence of a calf (≤3 years) reduced the number of prey captured by adult females from both populations, but disproportionately so for SRKW. SRKW adult males with a living mother captured more prey than those whose mother had died, whereas the opposite was true for NRKW adult males. Across populations, males foraged in deeper areas than females, and SRKW captured prey deeper than NRKW. These population-level differences in patterns of individual foraging behavior challenge the existing paradigm that females are the disproportionate foragers in gregarious resident killer whales, and demonstrate considerable variation in the foraging strategies across populations of an apex marine predator experiencing different environmental stressors.
... jerk) to estimate the number of prey capture attempts occurring in a dive. Foraging buzzes (with or without estimates of jerk) have been quantified in beaked whales (Family Ziphiidae) (Johnson et al., 2006;Stimpert et al., 2014;Siegal, 2020;Alcázar-Treviño et al., 2021;Visser et al., 2022), sperm whales (including Kogia spp.) (Fais et al., 2016;Tønnesen et al., 2020;Malinka et al., 2021), short-finned pilot whales (Globicephala macrorhynchus) (Aguilar Soto et al., 2008;Holt et al., 2021), narwhals (Monodon monoceros) (Ngô et al., 2021), smaller delphinids Arranz et al., 2016) and harbour porpoises (Phocoena phocoena) Wisniewska et al., 2018). ...
Bioenergetics is the study of how animals achieve energetic balance. Energetic balance results from the energetic expenditure of an individual and the energy they extract from their environment. Ingested energy depends on several extrinsic (e.g prey species, nutritional value and composition, prey density and availability) and intrinsic factors (e.g. foraging effort, success at catching prey, digestive processes and associated energy losses, and digestive capacity). While the focus in bioenergetic modelling is often on the energetic costs an animal incurs, the robust estimation of an individual’s energy intake is equally critical for producing meaningful predictions. Here, we review the components and processes that affect energy intake from ingested gross energy to biologically useful net energy (NE). The current state of knowledge of each parameter is reviewed, shedding light on research gaps to advance this field. The review highlighted that the foraging behaviour of many marine mammals is relatively well studied via biologging tags, with estimates of success rate typically assumed for most species. However, actual prey capture success rates are often only assumed, although we note studies that provide approaches for its estimation using current techniques. A comprehensive collation of the nutritional content of marine mammal prey species revealed a robust foundation from which prey quality (comprising prey species, size and energy density) can be assessed, though data remain unavailable for many prey species. Empirical information on various energy losses following ingestion of prey was unbalanced among marine mammal species, with considerably more literature available for pinnipeds. An increased understanding and accurate estimate of each of the components that comprise a species NE intake are an integral part of bioenergetics. Such models provide a key tool to investigate the effects of disturbance on marine mammals at an individual and population level and to support effective conservation and management.
... This additional noise input into the marine soundscape has raised concerns of inducing physiological responses such as chronic stress, acoustic masking of important biological cues as well as the displacement of animals from critical habitat (Clark et al., 2009;Pirotta et al., 2012;Rolland et al., 2012;Williams et al., 2014;Holt et al., 2021). For example, reductions in glucocorticoid levels, a hormone linked to physiological stress, were observed in right whales within the Bay of Fundy, Canada, in association with a reduction of vessel traffic (Rolland et al., 2012). ...
Increases in marine traffic represent a growing issue for marine wildlife, posing threats through the impacts of ship strikes and noise pollution. Baleen whales are especially vulnerable to these impacts, yet regional and species-specific information on exposure to such threats is lacking. This study uses AIS and observational data to provide the first assessment of baleen whale exposure to vessel traffic on the NW coast of Spain. Overlap with vessel traffic was detected for all areas where whales were sighted, indicating that these species may be at risk of vessel exposure and its associated impacts. Level of exposure to vessel traffic experienced by whales was species-specific, with risk of exposure appearing highest for minke whales. Vessel exposure also displayed intra- and inter-annual variability and a significant influence of feeding behaviour highlighting the need for dynamic management tools to minimise interactions between baleen whales and marine traffic off the Galician Coast.
... To describe it, accelerometers that register acceleration in three perpendicular directions are used. Over the past two decades, they have been increasingly used in studies of the behavior of marine mammals (cetaceans and pinnipeds), in particular, feeding behavior [3], response to anthropogenic noise [4], as well as rest and sleep states [5,6]. The beluga whale is one of the most popular objects of research among cetaceans, in particular, as an indicator of the state of Arctic ecosystems [7]. ...
... RS is one of the main types of behavior in cetaceans, the duration of which characterizes the metabolic rate, stress level, and health status of the animal [14]. To describe the behavior of animals, the predictive accuracy of a classifier of more than 90% is considered high [4,15]. However, the detection of AS in the beluga was less accurate (56-98%), whereas the assessment of the total duration was overestimated. ...
A noninvasive instrumental method of classification the behavior of the beluga whale (Delphinapterus leucas) based on the parameters of movement was evaluated. Motor activity was characterized by the mean and standard deviation of the beluga tail fluke acceleration. It was found that, using the "decision tree" algorithm, at least two types of beluga behaviors can be distinguished: resting at the surface and active swimming in the pool. The determination accuracy (depending on the parameter) was, on average, 81-97% for resting at the surface and 54-99% for active swimming behaviors. Differences between the accuracy of classification of resting at the surface based on three axis and overall body acceleration were minimal. In the future, the accuracy may be improved by using other acceleration parameters, shortening the interval of analysis, and optimizing the classification algorithms.
... However, serious noise pollution will damage the auditory system of marine animals and even cause the death of life. In order to protect the diversity of marine organisms, it is necessary to study the marine ambient noise (AN) [4][5][6]. ...
Marine ambient noise (AN) is a nonlinear and unstable signal, traditional dispersion entropy can only analyze the marine AN from a single scale, which is easy to cause the loss of information. To address this problem, we introduced multiscale dispersion entropy (MDE), and then a new feature extraction method of marine ambient noise based on MDE is proposed. We used MDE, multiscale permutation entropy (MPE), multiscale permutation Lempel–Ziv complexity (MPLZC), and multi-scale dispersion Lempel–Ziv complexity (MDLZC) to carry out feature extraction and classification recognition experiments for six ANs. The experimental results show that for the feature extraction methods based on MDE, MPE, MDLZC, and MPLZC, with the increase of the number of features, the feature extraction effect becomes better, and the average recognition rate (ARR) becomes higher; compared with other three feature extraction methods, the feature extraction method based on MDE has the best feature extraction effect and the highest ARR for the six ANs under the same feature number.
