Managing the wildlife tourism commons

ACKNOWLEDGMENTS This work received funding from the MASTS pooling initiative (the Marine Alliance for Science and Technology for Scotland) and their support is gratefully acknowledged.MASTS is funded by the Scottish Funding Council (grant reference HR09011) and contributing institutions. This work was stimulated by discussions with the Moray Firth Dolphin Space Programme and we particularly thank Ben Leyshon (Scottish Natural Heritage) for fruitful discussions. The authors would like to thank K. Barton and C. Konrad for their advice on biased random walks and correlated random fields, D.Murphy for useful discussions during the development of the simulations, and M. Marcoux for important comments on an earlier version of this work. Finally, we thank two anonymous reviewers, whose comments have greatly improved the manuscript.Peer reviewedPublisher PD

Modelling the impact of condition-dependent responses and lipid-store availability on the consequences of disturbance in a cetacean

This work was supported by the United States Office of Naval Research (awards N00014-17-1-2757 and N00014-19-1-2479).Lipid-store body condition is fundamental to how animals cope with environmental fluctuations, including anthropogenic change. As it provides an energetic buffer, body condition is expected to influence risk-taking strategies, with both positive and negative relationships between body condition and risk-taking posited in the literature. Individuals in good condition may take more risks due to state-dependent safety (‘ability-based’ explanation), or alternatively fewer risks due to asset protection and reduced need to undertake risky foraging (‘needs-based’ explanation). Such state-dependent responses could drive non-linear impacts of anthropogenic activities through feedback between body condition and behavioural disturbance. Here, we present a simple bioenergetic model that explicitly incorporates hypothetical body condition-dependent response strategies for a cetacean, the sperm whale. The model considered the consequences of state-dependent foraging cessation and availability of wax ester (WE) lipids for calf provisioning and female survival. We found strikingly different consequences of disturbance depending on strategy and WE availability scenarios. Compared with the null strategy, where responses to disturbance were independent of body condition, the needs-based strategy mitigated predicted reductions in provisioning by 10%–13%, while the ability-based strategy exaggerated reductions by 63%–113%. Lower WE availability resulted in more extreme outcomes because energy stores were smaller relative to the daily energy balance. In the 0% availability scenario, while the needs-based strategy reduced deaths by 100%, the ability-based strategy increased them by 335% relative to null and by 56% relative to the same strategy under the 5%–6.7% WE availability scenario. These results highlight that state-dependent disturbance responses and energy store availability could substantially impact the population consequences of disturbance. Our ability to set appropriate precautionary disturbance thresholds therefore requires empirical tests of ability- vs needs-based response modification as a function of body condition and a clearer understanding of energy store availability.Publisher PDFPeer reviewe

Central place foragers and moving stimuli : a hidden-state model to discriminate the processes affecting movement

We thank Orkney Islands Council for access to Eynhallow and Talisman Energy (UK) Ltd for fieldwork and equipment support. Marine Scotland provided access to anonymized VMS data. Handling and tagging of fulmars was conducted under licenses from the British Trust for Ornithology and the UK Home Office. EE was funded by a Marine Alliance for Science and Technology for Scotland/University of Aberdeen College of Life Sciences and Medicine studentship. We are grateful to Jason Matthiopoulos, Thomas Cornulier, Beth Scott, David Lusseau, Julien Martin and Tiago Marques for suggestions on model development, and to the many colleagues who assisted with fieldwork. We thank Emer Rogan and University College Cork for providing desk space to EP. Finally, we thank Editor-in-Chief Ben Sheldon, Associate Editor Luca Borger and three anonymous reviewers for their useful comments on the paper. Data available from the Dryad Digital Repository: https://doi:10.5061/dryad.0d377r6 (Pirotta et al., 2018)Peer reviewedPostprintPostprintPostprintPostprin

Emerging themes in population consequences of disturbance models

Funding: K.A.K., R.S.B. and D.P.C. were supported by the E&P Sound and Marine Life Joint Industry Programme (JIP) of the International Association of Oil and Gas Producers (IOGP) (grant no. 00-07-23). K.A.K. was also supported by the National Defense Science and Engineering Graduate (NDSEG) Fellowship. E.P. was supported by the Office of Naval Research (ONR) (grant no. N00014-19-1-2464). D.P.C. was also supported by ONR (grant no. N00014-18-1-2822).Assessing the non-lethal effects of disturbance from human activities is necessary for wildlife conservation and management. However, linking short-term responses to long-term impacts on individuals and populations is a significant hurdle for evaluating the risks of a proposed activity. The Population Consequences of Disturbance (PCoD) framework conceptually describes how disturbance can lead to changes in population dynamics, and its real-world application has led to a suite of quantitative models that can inform risk assessments. Here, we review PCoD models that forecast the possible consequences of a range of disturbance scenarios for marine mammals. In so doing, we identify common themes and highlight general principles to consider when assessing risk. We find that, when considered holistically, these models provide valuable insights into which contextual factors influence a population's degree of exposure and sensitivity to disturbance. We also discuss model assumptions and limitations, identify data gaps and suggest future research directions to enable PCoD models to better inform risk assessments and conservation and management decisions. The general principles explored can help wildlife managers and practitioners identify and prioritize the populations most vulnerable to disturbance and guide industry in planning activities that avoid or mitigate population-level effects.Publisher PDFPeer reviewe

Modeling the functional link between movement, feeding activity, and condition in a marine predator

The ability to quantify animals’ feeding activity and the resulting changes in their body condition as they move in the environment is fundamental to our understanding of a population’s ecology. We use satellite tracking data from northern elephant seals (Mirounga angustirostris), paired with simultaneous diving information, to develop a Bayesian state-space model that concurrently estimates an individual’s location, feeding activity, and changes in condition. The model identifies important foraging areas and times, the relative amount of feeding occurring therein, and thus the different behavioral strategies in which the seals engage. The fitness implications of these strategies can be assessed by looking at the resulting variation in individuals’ condition, which in turn affects the condition and survival of their offspring. Therefore, our results shed light on the processes affecting an individual’s decision-making as it moves and feeds in the environment. In addition, we demonstrate how the model can be used to simulate realistic patterns of disturbance at different stages of the trip, and how the predicted accumulation of lipid reserves varies as a consequence. Particularly, disturbing an animal in periods of high feeding activity or shortly after leaving the colony was predicted to have the potential to lead to starvation. In contrast, an individual could compensate even for very severe disturbance if such disturbance occurred outside the main foraging grounds. Our modeling approach is applicable to marine mammal species that perform drift dives and can be extended to other species where an individual’s buoyancy can be inferred from its diving behavior

Movements, diving behaviour and diet of C-type killer whales (Orcinus orca) in the Ross Sea, Antarctica

The fish‐eating, type‐C ecotype, killer whale is a top predator in the Ross Sea, Antarctica. Increasing knowledge of this animal's foraging habitats, diet and movement patterns is listed amongst the research priorities adopted under the framework of the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). To contribute to this goal, satellite transmitters were deployed on 10 type‐C killer whales and skin biopsies were obtained from seven individuals in Terra Nova Bay (Ross Sea) during austral summer (January-February) 2015. Hierarchical switching state-space models (hSSSM) were applied to Argos satellite tracking data to describe the movements of tagged whales, which were then paired with available diving data. Stable isotopes analyses were performed on the biopsy samples to describe the diet. A total of 8,803 Argos locations were available to fit the hSSSM. All whales engaged in potential foraging activity in localized areas along the Ross Sea coastline, followed by uninterrupted travel (i.e. migration) outside Antarctic waters, with no evidence of foraging activity. The pattern of deeper dives matched the occurrence of encamped behaviour indicated by the hSSSM results. The stable isotopes analysis indicated that Antarctic toothfish comprised the largest component (35%) of the prey biomass, raising concerns since this species is targeted by commercial fishery in the Ross Sea Region. These results provide new insights into the ecology of type‐C killer whales in the Ross Sea Region, underlining a potential threat from commercial fishing in the area. Considering the recent establishment of the Ross Sea Region Marine Protected Area, these findings will contribute to the required Research and Monitoring Programme of the Marine Protected Area and provide new empirical evidence to inform conservation measures in the existing Terra Nova Bay Antarctic Special Protected Are

Modeling individual growth reveals decreasing gray whale body length and correlations with ocean climate indices at multiple scales

Funding: This work was supported by the Office of Naval Research Marine Mammals and Biology Program (grant number: N00014-20-1-2760); the NOAA National Marine Fisheries Service Office of Science and Technology Ocean Acoustics Program (2016 and 2017) (grant number: 50-27); the Oregon State University Marine Mammal Institute; and Oregon Sea Grant Program Development funds (2018) (grant number: RECO- 40-PD).Changes in body size have been documented across taxa in response to human activities and climate change. Body size influences many aspects of an individual's physiology, behavior, and ecology, ultimately affecting life history performance and resilience to stressors. In this study, we developed an analytical approach to model individual growth patterns using aerial imagery collected via drones, which can be used to investigate shifts in body size in a population and the associated drivers. We applied the method to a large morphological dataset of gray whales (Eschrichtius robustus) using a distinct foraging ground along the NE Pacific coast, and found that the asymptotic length of these whales has declined since around the year 2000 at an average rate of 0.05–0.12 m/y. The decline has been stronger in females, which are estimated to be now comparable in size to males, minimizing sexual dimorphism. We show that the decline in asymptotic length is correlated with two oceanographic metrics acting as proxies of habitat quality at different scales: the mean Pacific Decadal Oscillation index, and the mean ratio between upwelling intensity in a season and the number of relaxation events. These results suggest that the decline in gray whale body size may represent a plastic response to changing environmental conditions. Decreasing body size could have cascading effects on the population's demography, ability to adjust to environmental changes, and ecological influence on the structure of their community. This finding adds to the mounting evidence that body size is shrinking in several marine populations in association with climate change and other anthropogenic stressors. Our modeling approach is broadly applicable across multiple systems where morphological data on megafauna are collected using drones.Peer reviewe

Prey encounters and spatial memory influence use of foraging patches in a marine central place forager

This study was carried out as part of the Moray Firth Marine Mammal Monitoring Programme, a joint industry, academic and government strategic research project with funding from Beatrice Offshore Wind Ltd and Moray Offshore Renewables Ltd (MORL).Given the patchiness and long-term predictability of marine resources, memory of high-quality foraging grounds is expected to provide fitness advantages for central place foragers. However, it remains challenging to characterize how marine predators integrate memory with recent prey encounters to adjust fine-scale movement and use of foraging patches. Here, we used two months of movement data from harbour seals (Phoca vitulina) to quantify the repeatability in foraging patches as a proxy for memory. We then integrated these data into analyses of fine-scale movement and underwater behaviour to test how both spatial memory and prey encounter rates influenced the seals' area-restricted search (ARS) behaviour. Specifically, we used one month's GPS data from 29 individuals to build spatial memory maps of searched areas and archived accelerometery data from a subset of five individuals to detect prey catch attempts, a proxy for prey encounters. Individuals were highly consistent in the areas they visited over two consecutive months. Hidden Markov models showed that both spatial memory and prey encounters increased the probability of seals initiating ARS. These results provide evidence that predators use memory to adjust their fine-scale movement, and this ability should be accounted for in movement models.PostprintPeer reviewe

Growing into it : evidence of an ontogenetic shift in grey whale use of foraging tactics

Funding: Alexa Kownacki Endowed Research Award Fund. Data collection was supported by the NOAA National Marine Fisheries Service Office of Science and Technology Ocean Acoustics Program (2016 and 2017; 50-27), the Oregon Sea Grant Program Development funds (2018; RECO-40-PD), the Oregon State University Marine Mammal Institute (2019) and the Office of Naval Research Marine Mammals and Biology program (2020e2022; N00014-20-1-2760).Individual specialization may occur relative to diet, behaviour or spatial distribution, potentially leading to differential resource and space use within a population. While specializations have been documented across many animal populations, the underlaying causes of individual specialization (e.g. morphology, age or sex) are not always identified. Causes of specialization can be especially challenging to uncover for large, long-lived marine animals. We used a Bayesian multilevel, multinomial logistic regression model to study the relationships between grey whale, Eschrichtius robustus, use of foraging tactics and morphology (body length and condition), while accounting for habitat characteristics and individual variation in tactic use. The model was informed by a 7-year longitudinal data set of concurrent morphology and foraging behaviour collected using drones. We found evidence of an ontogenetic shift in the use of foraging tactics associated with body length (a proxy for age). Individual specialization in behaviour was also associated with water depth and habitat. After accounting for the effects of these covariates, there was some residual individual level variation in the use of different foraging tactics. Our findings demonstrate variation in resource and habitat use within a baleen whale population at the individual level relative to body length and habitat, suggesting that individual spatial distribution and access to prey may vary by age class. Our results can be applied to investigate whether juveniles and adults differ in their foraging success and resilience to stressors.Peer reviewe

Estimating body mass of sperm whales from aerial photographs

We wish to thank Fundación Biodiversidad for supporting COLCA project and all the ecovolunteers involved in the fieldwork of the Balearic Sperm Whale project. We are grateful to OceanCare (Switzerland) for their continuous support of the sperm whale research and conservation activities of the PCRI since 2008 and to Prof. Kostas Kostarelos and the University of Manchester for organizing the crowd-funding project “Nanowhales” to cofund the research expedition of 2019 along the Hellenic Trench. This paper represents HIMB and SOEST contribution nos. 1903 and 11568, respectively.Body mass is a fundamental feature of animal physiology. Although sperm whales (Physeter macrocephalus) are the largest toothed predators on earth, body mass is seldom included in studies of their ecophysiology and bioenergetics due to the inherent difficulties of obtaining direct measurements. We used UAV‐photogrammetry to estimate the weight of free‐ranging sperm whales. Aerial photographs (23 calves, 11 juveniles, 55 nonmother adults, 13 mothers) were collected in the Eastern Caribbean and Mediterranean Sea during 2017–2020. Body length, widths, and heights (dorso‐ventral distance at 5% increments) were measured from dorsal and lateral photographs, while body volume was calculated using an elliptical model. Volume varied noticeably (12.01 ± 4.79 m3) in larger animals (>8 m), indicating fluctuations in body condition of adults and mothers. Volume was converted to mass, using tissue‐density estimates from catch data, animal‐borne tags, and body‐tissue composition. Average total body density ranged from 834 to 1,003 kg/m3, while the weight predictions matched with existing measurements and weight‐length relationships. Our body‐mass models can be used to study sperm whale bioenergetics, including inter‐ and intraseasonal variations in body condition, somatic growth, metabolic rates, and cost of reproduction.Publisher PDFPeer reviewe