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  • 1
    Online Resource
    Online Resource
    Seismic surveys near gray whale feeding areas off Sakhalin Island, Russia: assessing impact and mitigation effectiveness
    Springer Science and Business Media LLC ; 2022
    In:  Environmental Monitoring and Assessment Vol. 194, No. S1 ( 2022-09)
    Details
    In: Environmental Monitoring and Assessment, Springer Science and Business Media LLC, Vol. 194, No. S1 ( 2022-09)
    Abstract: In 2015, two oil and gas companies conducted seismic surveys along the northeast coast of Sakhalin Island, Russia, near western gray whale ( Eschrichtius robustus ) feeding areas. This population of whales was listed as Critically Endangered at the time of the operations described here but has been reclassified as Endangered since 2018. The number and duration of the 2015 seismic surveys surpassed the level of previous seismic survey activity in this area, elevating concerns regarding disturbance of feeding gray whales and the potential for auditory injury. Exxon Neftegas Limited (ENL) developed a mitigation approach to address these concerns and, more importantly, implemented a comprehensive data collection strategy to assess the effectiveness of this approach. The mitigation approach prioritized completion of the seismic surveys closest to the nearshore feeding area as early in the season as possible, when fewer gray whales would be present. This was accomplished by increasing operational efficiency through the use of multiple seismic vessels and by establishing zones with specific seasonal criteria determining when air gun shutdowns would be implemented. These zones and seasonal criteria were based on pre-season modeled acoustic footprints of the air gun array and on gray whale distribution data collected over the previous 10 years. Real-time acoustic and whale sighting data were instrumental in the implementation of air gun shutdowns. The mitigation effectiveness of these shutdowns was assessed through analyzing short-term behavioral responses and shifts in gray whale distribution due to sound exposure. The overall mitigation strategy of an early survey completion was assessed through bioenergetics models that predict how reduced foraging activity might affect gray whale reproduction and maternal survival. This assessment relied on a total of 17 shore-based and 5 vessel-based teams collecting behavior, distribution, photo-identification, prey, and acoustic data. This paper describes the mitigation approach, the implementation of mitigation measures using real-time acoustic and gray whale location data, and the strategy to assess impacts and mitigation effectiveness.
    Type of Medium: Online Resource
    ISSN: 0167-6369 , 1573-2959
    URL: Article
    DOI: 10.1007/s10661-022-10016-9
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2012242-1
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  • 2
    Online Resource
    Online Resource
    Western gray whales on their summer feeding ground off Sakhalin Island in 2015: who is foraging where?
    Springer Science and Business Media LLC ; 2022
    In:  Environmental Monitoring and Assessment Vol. 194, No. S1 ( 2022-09)
    Details
    In: Environmental Monitoring and Assessment, Springer Science and Business Media LLC, Vol. 194, No. S1 ( 2022-09)
    Abstract: In the face of cumulative effects of oil and gas activities on the endangered western gray whale, informed management decisions rely on knowledge of gray whale spatial use patterns as a function of demographic group and prey energy. In particular, the gray whale foraging ground off Sakhalin Island consists of two distinct areas (nearshore and offshore) with the offshore feeding area exhibiting markedly high prey energy content. Based on photo-identification data collected from 2002 to 2015, we determined that gray whale use of the offshore feeding area increased with age. Pregnant females were more likely to be sighted only nearshore when nearshore prey energy and the proportion of nearshore energy from amphipods were higher. Likewise, females arriving with calves were less likely to be sighted offshore when the proportion of nearshore energy from amphipods was higher. Photo-identification effort in 2015 was increased substantially, with the intent of maximizing resighting data of individual whales to determine the relative proportion of different demographic groups utilizing the nearshore and offshore feeding areas. Comparing sighting data collected in 2015 with data from all previous years combined, mothers arriving with calves were sighted in the offshore feeding area earlier in 2015, with no evidence that they returned to forage nearshore later in the season. Other reproductive females constituted a higher proportion of the animals foraging nearshore prior to 2015, while juveniles were a higher proportion during 2015. Thus, the offshore feeding area is an important component of the gray whales’ annual life cycle, particularly if nearshore prey energy continues to decline, and offshore anthropogenic activities need to be monitored and addressed.
    Type of Medium: Online Resource
    ISSN: 0167-6369 , 1573-2959
    URL: Article
    DOI: 10.1007/s10661-022-10022-x
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2012242-1
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  • 3
    Online Resource
    Online Resource
    Methods and models to determine perinatal status of Florida manatee carcasses
    Wiley ; 2008
    In:  Marine Mammal Science ( 2008-09)
    Details
    In: Marine Mammal Science, Wiley, ( 2008-09)
    Type of Medium: Online Resource
    ISSN: 0824-0469 , 1748-7692
    URL: Article
    DOI: 10.1111/j.1748-7692.2008.00232.x
    Language: English
    Publisher: Wiley
    Publication Date: 2008
    detail.hit.zdb_id: 12787-5
    detail.hit.zdb_id: 2218018-7
    SSG: 12
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    Online Resource
  • 4
    Online Resource
    Online Resource
    Understanding the population consequences of disturbance
    Wiley ; 2018
    In:  Ecology and Evolution Vol. 8, No. 19 ( 2018-10), p. 9934-9946
    Details
    In: Ecology and Evolution, Wiley, Vol. 8, No. 19 ( 2018-10), p. 9934-9946
    Abstract: Managing the nonlethal effects of disturbance on wildlife populations has been a long‐term goal for decision makers, managers, and ecologists, and assessment of these effects is currently required by European Union and United States legislation. However, robust assessment of these effects is challenging. The management of human activities that have nonlethal effects on wildlife is a specific example of a fundamental ecological problem: how to understand the population‐level consequences of changes in the behavior or physiology of individual animals that are caused by external stressors. In this study, we review recent applications of a conceptual framework for assessing and predicting these consequences for marine mammal populations. We explore the range of models that can be used to formalize the approach and we identify critical research gaps. We also provide a decision tree that can be used to select the most appropriate model structure given the available data. Synthesis and applications: The implementation of this framework has moved the focus of discussion of the management of nonlethal disturbances on marine mammal populations away from a rhetorical debate about defining negligible impact and toward a quantitative understanding of long‐term population‐level effects. Here we demonstrate the framework's general applicability to other marine and terrestrial systems and show how it can support integrated modeling of the proximate and ultimate mechanisms that regulate trait‐mediated, indirect interactions in ecological communities, that is, the nonconsumptive effects of a predator or stressor on a species' behavior, physiology, or life history.
    Type of Medium: Online Resource
    ISSN: 2045-7758 , 2045-7758
    URL: Issue
    URL: Article
    DOI: 10.1002/ece3.2018.8.issue-19
    DOI: 10.1002/ece3.4458
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 2635675-2
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  • 5
    Online Resource
    Online Resource
    A bioenergetics approach to understanding the population consequences of acoustic disturbance.
    Acoustical Society of America (ASA) ; 2011
    In:  The Journal of the Acoustical Society of America Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2395-2395
    Details
    In: The Journal of the Acoustical Society of America, Acoustical Society of America (ASA), Vol. 129, No. 4_Supplement ( 2011-04-01), p. 2395-2395
    Abstract: [A major hurdle with marine mammal conservation and management is to know if and when measurable short term responses result in biologically meaningful changes in populations. We are developing a bioenergetics approach to parametrize the transfer functions developed in the conceptual model developed by the NRC Committee on the population consequences of acoustic disturbance (PCAD). Our effort is directed at quantifying the life functions that are linked to vital rates, and how changes in these vital rates affect populations. Such an approach can identify species and or particular life history characteristics that are likely to be sensitive or resilient to acoustic disturbance. Using species that represent the range of life history patterns observed in marine mammals we are analyzing the existing data to determine whether there is a linkage between fine scale measurements of foraging behavior and reproductive success and survival. These data are being used to develop a time-activity budget to produce a first order quantitative assessment of the potential significance in terms of lost energy and/or time that foraging behavior or habitat utilization is potentially affected by acoustic disturbance.
    Type of Medium: Online Resource
    ISSN: 0001-4966 , 1520-8524
    URL: Article
    DOI: 10.1121/1.3587786
    RVK:
    EQ 1000
    Language: English
    Publisher: Acoustical Society of America (ASA)
    Publication Date: 2011
    detail.hit.zdb_id: 1461063-2
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  • 6
    Online Resource
    Online Resource
    Comparison of closing and passing mode from a line-transect survey of delphinids in the eastern Tropical Pacific Ocean
    International Whaling Commission ; 2023
    In:  J. Cetacean Res. Manage. Vol. 11, No. 3 ( 2023-02-14), p. 253-265
    Details
    In: J. Cetacean Res. Manage., International Whaling Commission, Vol. 11, No. 3 ( 2023-02-14), p. 253-265
    Abstract: Line-transect ship surveys are the primary method used to estimate abundance of pelagic cetaceans. However, survey methods are often modified from traditional methods because observers must approach cetacean groups to identify species and estimate group size. Returning to the trackline after approaching a school dramatically reduces the amount of effective survey time, so ships often resume survey effort at the sighting but parallel to the original trackline (closing mode). Survey effort is no longer independent of group locations, and it is unclear how such methodological modifications affect overall abundance estimates. This research presents the results of a study designed to determine the effects of closing mode methods on abundance estimation for cetacean species in the eastern tropical Pacific. Species identification and group size estimation in closing mode are compared with results using survey techniques where the ship does not approach or slow down to investigate a sighting (passing mode). Both empirical data and simulations were used to compare group encounter rates in the two modes and to better understand the mechanisms that might lead to an encounter rate bias in closing mode. As seen in similar studies, observers are able to identify to the species level less frequently in passing mode (81% vs 57% of sightings), and point estimates of delphinid group size were 58% lower in passing mode than closing mode at distances between 1.0 and 5.5km from the trackline. In addition, uncertainty in group size both within and between observers was higher in passing mode. Closing mode delphinid group encounter rates were generally 20–25% lower than passing mode delphinid group encounter rates. Simulations showed the empirically lower encounter rates in closing mode are due to a loss in detection probability caused by the stop-start nature of the survey method. The closing mode encounter rate bias is greater when groups are in fewer and/or tighter clusters and when overall group density is higher. Methodological adjustments and analytical solutions to improve group size estimation and species identification in passing mode and reduce closing mode encounter rate bias are analytically complex and would also result in the loss of important additional life history data. Nevertheless, such avenues should be explored further.
    Type of Medium: Online Resource
    ISSN: 2312-2706 , 1561-0713
    URL: Issue
    URL: Article
    DOI: 10.47536/jcrm.v11i3
    DOI: 10.47536/jcrm.v11i3.605
    Language: Unknown
    Publisher: International Whaling Commission
    Publication Date: 2023
    detail.hit.zdb_id: 2744616-5
    SSG: 21,3
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    A state-dependent model for assessing the population consequences of disturbance on income-breeding mammals
    Elsevier BV ; 2018
    In:  Ecological Modelling Vol. 385 ( 2018-10), p. 133-144
    Details
    In: Ecological Modelling, Elsevier BV, Vol. 385 ( 2018-10), p. 133-144
    Type of Medium: Online Resource
    ISSN: 0304-3800
    URL: Article
    DOI: 10.1016/j.ecolmodel.2018.07.016
    RVK:
    AR 10100
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2018
    detail.hit.zdb_id: 191971-4
    detail.hit.zdb_id: 2000879-X
    SSG: 12
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  • 8
    Online Resource
    Online Resource
    Top-down and bottom-up influences on demographic rates of Antarctic fur seals Arctocephalus gazella
    Wiley ; 2013
    In:  Journal of Animal Ecology Vol. 82, No. 4 ( 2013-07), p. 903-911
    Details
    In: Journal of Animal Ecology, Wiley, Vol. 82, No. 4 ( 2013-07), p. 903-911
    Type of Medium: Online Resource
    ISSN: 0021-8790
    URL: Issue
    URL: Article
    DOI: 10.1111/jane.2013.82.issue-4
    DOI: 10.1111/1365-2656.12059
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2013
    detail.hit.zdb_id: 2006616-8
    SSG: 12
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  • 9
    Online Resource
    Online Resource
    Modeling the functional link between movement, feeding activity, and condition in a marine predator
    Oxford University Press (OUP) ; 2019
    In:  Behavioral Ecology Vol. 30, No. 2 ( 2019-04-05), p. 434-445
    Details
    In: Behavioral Ecology, Oxford University Press (OUP), Vol. 30, No. 2 ( 2019-04-05), p. 434-445
    Abstract: 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.
    Type of Medium: Online Resource
    ISSN: 1045-2249 , 1465-7279
    URL: Article
    DOI: 10.1093/beheco/ary183
    RVK:
    WA 15000
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2019
    detail.hit.zdb_id: 1496189-1
    SSG: 12
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  • 10
    Online Resource
    Online Resource
    Benthic studies adjacent to Sakhalin Island, Russia, 2015 II: energy content of the zoobenthos in western gray whale feeding grounds
    Springer Science and Business Media LLC ; 2022
    In:  Environmental Monitoring and Assessment Vol. 194, No. S1 ( 2022-09)
    Details
    In: Environmental Monitoring and Assessment, Springer Science and Business Media LLC, Vol. 194, No. S1 ( 2022-09)
    Abstract: The waters adjacent to the northeastern coast of Sakhalin Island, Russia, are an important feeding ground for the endangered western gray whale. Data on the energy available to foraging whales from their prey resources is required for researchers interested in modeling the bioenergetics of whale foraging, but little energy content information is available for the benthic prey communities of gray whales in this region. In this study, we describe the energy density (ED), biomass, and total energy availability (ED × biomass) of benthic prey sampled from two gray whale foraging areas adjacent to Sakhalin Island: the nearshore and offshore feeding areas. ED varied almost seven-fold among benthic taxa, ranging from 1.11 to 7.62 kJ/g wet mass. Although there was considerable variation within most prey groups, amphipods had the highest mean ED of all of groups examined (5.58 ± 1.44 kJ/g wet mass). Small sample sizes precluded us from detecting any seasonal or spatial differences in mean ED within or among taxa; however, mean biomass in the offshore feeding area was, in some cases, an order of magnitude higher than mean estimates in the nearshore feeding area, resulting in higher mean total energy available to foraging gray whales offshore (958–3313 kJ/m 2 ) compared to nearshore (223–495 kJ/m 2 ). While the proportion of total energy accounted for by amphipods was variable, this prey group generally made up a higher proportion of the total energy available in the benthos of the offshore feeding area than in the benthos of the nearshore feeding area. Data presented here will be used to inform bioenergetics modeling of the vital rates of mature females in an effort to improve understanding of population growth limits for western gray whales.
    Type of Medium: Online Resource
    ISSN: 0167-6369 , 1573-2959
    URL: Article
    DOI: 10.1007/s10661-022-10020-z
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2012242-1
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