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Gailey G, Zykov M, Sychenko O, Rutenko A, Blanchard AL, Aerts L, Melton RH. Gray whale density during seismic surveys near their Sakhalin feeding ground. Environ Monit Assess 2022; 194:739. [PMID: 36255495 PMCID: PMC9579086 DOI: 10.1007/s10661-022-10025-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Accepted: 04/04/2022] [Indexed: 05/31/2023]
Abstract
Oil and gas development off northeastern Sakhalin Island, Russia, has exposed the western gray whale population on their summer-fall foraging grounds to a range of anthropogenic activities, such as pile driving, dredging, pipeline installation, and seismic surveys. In 2015, the number of seismic surveys within a feeding season surpassed the level of the number and duration of previous seismic survey activities known to have occurred close to the gray whales' feeding ground, with the potential to cause disturbance to their feeding activity. To examine the extent that gray whales were potentially avoiding areas when exposed to seismic and vessel sounds, shore-based teams monitored the abundance and distribution of gray whales from 13 stations that encompassed the known nearshore feeding area. Gray whale density was examined in relation to natural (spatial, temporal, and prey energy) and anthropogenic (cumulative sound exposure from vessel and seismic sounds) explanatory variables using Generalized Additive Models (GAM). Distance from shore, water depth, date, and northing explained a significant amount of variation in gray whale densities. Prey energy from crustaceans, specifically amphipods, isopods, and cumaceans also significantly influenced gray whale densities in the nearshore feeding area. Increasing cumulative exposure to vessel and seismic sounds resulted in both a short- and longer-term decline in gray whale density in an area. This study provides further insights about western gray whale responses to anthropogenic activity in proximity to and within the nearshore feeding area. As the frequency of seismic surveys and other non-oil and gas anthropogenic activity are expected to increase off Sakhalin Island, it is critical to continue to monitor and assess potential impacts on this endangered population of gray whales.
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Affiliation(s)
- Glenn Gailey
- Cetacean EcoSystem Research, Olympia, WA, 98512, USA.
| | - Mikhail Zykov
- JASCO Applied Sciences Ltd, Dartmouth, NS, B3B 1Z1, Canada
| | - Olga Sychenko
- Cetacean EcoSystem Research, Olympia, WA, 98512, USA
| | - Alexander Rutenko
- Far East Branch of Russian Academy of Sciences, V.I. Il'ichev Pacific Oceanological Institute, Vladivostok, 690041, Russia
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Gailey G, Sychenko O, Zykov M, Rutenko A, Blanchard A, Melton RH. Western gray whale behavioral response to seismic surveys during their foraging season. Environ Monit Assess 2022; 194:740. [PMID: 36255529 PMCID: PMC9579098 DOI: 10.1007/s10661-022-10023-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 10/08/2021] [Indexed: 05/31/2023]
Abstract
Gray whales utilizing their foraging grounds off northeastern Sakhalin Island, Russia, have been increasingly exposed to anthropogenic activities related to oil and gas development over the past two decades. In 2015, four seismic vessels, contracted by two operators, conducted surveys near and within the gray whale feeding grounds. Mitigation and monitoring plans were developed prior to the survey and implemented in the field, with real-time data transfers to assist the implementation of measures aimed at minimizing impacts of acoustic exposure. This study examined the behavioral response of gray whales relative to vessel proximities and sounds generated during seismic exploration. Five shore-based teams monitored gray whale behavior from 1 June to 30 September using theodolite tracking and focal follow methodologies. Behavioral data were combined with acoustic and benthic information from studies conducted during the same period. A total of 1270 tracks (mean duration = 0.9 h) and 401 focal follows (1.1 h) were collected with gray whales exposed to sounds ranging from 59 to 172 dB re 1 μPa2 SPL. Mixed models were used to examine 13 movement and 10 respiration response variables relative to "natural," acoustic, and non-acoustic explanatory variables. Water depth and behavioral state were the largest predictors of gray whale movement and respiration patterns. As vessels approached whales with increasing seismic/vessel sound exposure levels and decreasing distances, several gray whale movement and respiration response variables significantly changed (increasing speed, directionality, surface time, respiration intervals, etc.). Although the mitigation measures employed could have reduced larger/long-term responses and sensitization to the seismic activities, this study illustrates that mitigation measures did not eliminate behavioral responses, at least in the short-term, of feeding gray whales to the activities.
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Affiliation(s)
| | | | - Mikhail Zykov
- JASCO Applied Sciences (Canada) Ltd, Victoria, BC, Canada
| | - Alexander Rutenko
- V.I. Il'ichev Pacific Oceanological Institute FEB RAS, Vladivostok, Russia
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Schwarz L, McHuron E, Mangel M, Gailey G, Sychenko O. Gray whale habitat use and reproductive success during seismic surveys near their feeding grounds: comparing state-dependent life history models and field data. Environ Monit Assess 2022; 194:733. [PMID: 36255497 PMCID: PMC9579109 DOI: 10.1007/s10661-022-10024-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 02/05/2022] [Indexed: 05/31/2023]
Abstract
We used a stochastic dynamic programming (SDP) model to quantify the consequences of disturbance on pregnant western gray whales during one foraging season. The SDP model has a firm basis in bioenergetics, but detailed knowledge of minimum reproductive length of females (Lmin) and the relationship between length and reproductive success (Rfit) was lacking. We varied model assumptions to determine their effects on predictions of habitat use, proportion of animals disturbed, reproductive success, and the effects of disturbance. Smaller Lmin values led to higher predicted nearshore habitat use. Changes in Lmin and Rfit had little effect on predictions of the effect of disturbance. Reproductive success increased with increased Lmin and with higher probability of reproductive success by length. Multiple seismic surveys were conducted in 2015 off the northeast coast of Sakhalin Island, with concomitant benthic prey surveys, photo-identification studies, and whale distribution sampling, thus providing a unique opportunity to compare output from SDP models with empirical observations. SDP model predictions of reproductive success and habitat use were similar with and without acoustic disturbance, and SDP predictions of reproductive success and large-scale habitat use were generally similar to values and trends in the data. However, empirical estimates of the proportion of pregnant females nearshore were much higher than SDP model predictions (a large effect, measured by Cohen's d) during the first week, and the SDP model overestimated whale density in the south and underestimated density around the mouth of Piltun Bay. Such differences in nearshore habitat use would not affect SDP predictions of reproductive success or survival under the current seismic air gun disturbance scenario.
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Affiliation(s)
- Lisa Schwarz
- Institute of Marine Sciences, University of California, Santa Cruz, CA, 95064, USA.
| | - Elizabeth McHuron
- Institute of Marine Sciences, University of California, Santa Cruz, CA, 95064, USA
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, CA, 95064, USA
- Ocean, and Ecosystem Studies, Cooperative Institute for Climate, University of Washington, Seattle, WA, 98195, USA
| | - Marc Mangel
- Institute of Marine Sciences, University of California, Santa Cruz, CA, 95064, USA
- Theoretical Ecology Group, Department of Biology, University of Bergen, 9020, Bergen, Norway
- Puget Sound Institute, University of Washington, Tacoma, WA, 98402, USA
| | - Glenn Gailey
- Cetacean EcoSystem Research, Lacey, WA, 98516, USA
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Blanchard AL, Ainsworth L, Gailey G, Demchenko NL, Shcherbakov IA. Benthic studies adjacent to Sakhalin Island, Russia 2015 III: benthic energy density spatial models in the nearshore gray whale feeding area. Environ Monit Assess 2022; 194:741. [PMID: 36255557 PMCID: PMC9579071 DOI: 10.1007/s10661-022-10018-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 05/25/2021] [Indexed: 05/25/2023]
Abstract
Energy densities of six dominant benthic groups (Actinopterygii, Amphipoda, Bivalvia, Cumacea, Isopoda, and Polychaeta) and total prey energy were modeled for the nearshore western gray whale feeding area, Sakhalin Island, Russia, as part of a multi-disciplinary research program in the summer of 2015. Energy was modeled using generalized additive mixed models (GAMM) with accommodations for zero-inflation (logistic regression and hurdle models) and regression predictions combined with kriging to interpolate energy densities across the nearshore feeding area. Amphipoda energy density was the highest nearshore and in the south whereas Bivalvia energy density was the highest offshore and in the northern portion of the study area. Total energy was the highest in mid-range distances from shore and in the north. Amphipoda energy density was higher than minimum energy estimates defining gray whale feeding habitats (312-442 kJ/m2) in 13% of the nearshore feeding area whereas total prey energy density was higher than the minimum energy requirement in 49% of the habitat. Inverse distance-weighted interpolations of Amphipoda energy provided a broader scale representation of the data whereas kriging estimates were spatially limited but more representative of higher density in the southern portion of the study area. Both methods represented the general trend of higher Amphipoda energy density nearshore but with significant differences that highlight the value of using multiple methods to model patterns in highly complex environments.
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Affiliation(s)
| | | | - Glenn Gailey
- Cetacean EcoSystem Research, Lacey, WA, 98512, USA
| | - Natalia L Demchenko
- A.V. Zhirmunsky National Science Center of Marine Biology, Far East Branch of Russian Academy of Sciences, Vladivostok, Russia
| | - Ilya A Shcherbakov
- A.V. Zhirmunsky National Science Center of Marine Biology, Far East Branch of Russian Academy of Sciences, Vladivostok, Russia
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Aerts L, Jenkerson MR, Nechayuk VE, Gailey G, Racca R, Blanchard AL, Schwarz LK, Melton HR. Seismic surveys near gray whale feeding areas off Sakhalin Island, Russia: assessing impact and mitigation effectiveness. Environ Monit Assess 2022; 194:746. [PMID: 36255494 PMCID: PMC9579104 DOI: 10.1007/s10661-022-10016-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Accepted: 04/21/2021] [Indexed: 05/25/2023]
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.
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Affiliation(s)
| | | | | | - Glenn Gailey
- Cetacean EcoSystem Research, Lacey, WA, 98512, USA
| | - Roberto Racca
- JASCO Applied Sciences, Victoria, BC, V8Z 7X8, Canada
| | | | - Lisa K Schwarz
- Ocean Sciences and Institute of Marine Sciences, University of California, Santa Cruz, CA, 95060, USA
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Schwarz LK, Gailey G, Tyurneva O, Yakovlev Y, Sychenko O, van der Wolf P, Vertyankin VV. Western gray whales on their summer feeding ground off Sakhalin Island in 2015: who is foraging where? Environ Monit Assess 2022; 194:738. [PMID: 36255559 PMCID: PMC9579093 DOI: 10.1007/s10661-022-10022-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 06/24/2021] [Indexed: 05/31/2023]
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.
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Affiliation(s)
- Lisa K Schwarz
- Ocean Sciences and Institute of Marine Sciences, University of California, Santa Cruz, CA, 95060, USA.
| | - Glenn Gailey
- Cetacean EcoSystem Research, Lacey, WA, 98516, USA
| | - Olga Tyurneva
- National Science Center of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok, 690041, Russia
| | - Yuri Yakovlev
- National Science Center of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok, 690041, Russia
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McHuron EA, Aerts L, Gailey G, Sychenko O, Costa DP, Mangel M, Schwarz LK. Predicting the population consequences of acoustic disturbance, with application to an endangered gray whale population. Ecol Appl 2021; 31:e02440. [PMID: 34374143 DOI: 10.1002/eap.2440] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 02/05/2021] [Accepted: 03/22/2021] [Indexed: 06/13/2023]
Abstract
Acoustic disturbance is a growing conservation concern for wildlife populations because it can elicit physiological and behavioral responses that can have cascading impacts on population dynamics. State-dependent behavioral and life history models implemented via Stochastic Dynamic Programming (SDP) provide a natural framework for quantifying biologically meaningful population changes resulting from disturbance by linking environment, physiology, and metrics of fitness. We developed an SDP model using the endangered western gray whale (Eschrichtius robustus) as a case study because they experience acoustic disturbance on their summer foraging grounds. We modeled the behavior and physiological dynamics of pregnant females as they arrived on the feeding grounds and predicted the probability of female and offspring survival, with and without acoustic disturbance and in the presence/absence of high prey availability. Upon arrival in mid-May, pregnant females initially exhibited relatively random behavior before they transitioned to intensive feeding that resulted in continual fat mass gain until departure. This shift in behavior co-occurred with a change in spatial distribution; early in the season, whales were more equally distributed among foraging areas with moderate to high energy availability, whereas by mid-July whales transitioned to predominate use of the location that had the highest energy availability. Exclusion from energy-rich offshore areas led to reproductive failure and in extreme cases, mortality of adult females that had lasting impacts on population dynamics. Simulated disturbances in nearshore foraging areas had little to no impact on female survival or reproductive success at the population level. At the individual level, the impact of disturbance was unequally distributed across females of different lengths, both with respect to the number of times an individual was disturbed and the impact of disturbance on vital rates. Our results highlight the susceptibility of large capital breeders to reductions in prey availability, and indicate that who, where, and when individuals are disturbed are likely to be important considerations when assessing the impacts of acoustic activities. This model provides a framework to inform planned acoustic disturbances and assess the effectiveness of mitigation strategies for large capital breeders.
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Affiliation(s)
- Elizabeth A McHuron
- Institute of Marine Sciences, University of California, Santa Cruz, California, 95064, USA
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, 95064, USA
| | | | - Glenn Gailey
- Cetacean EcoSystem Research, Lacey, Washington, 98516, USA
| | - Olga Sychenko
- Cetacean EcoSystem Research, Lacey, Washington, 98516, USA
| | - Daniel P Costa
- Department of Ecology and Evolutionary Biology, University of California, Santa Cruz, California, 95064, USA
| | - Marc Mangel
- Institute of Marine Sciences, University of California, Santa Cruz, California, 95064, USA
- Theoretical Ecology Group, Department of Biology, University of Bergen, Bergen, 9020, Norway
- Puget Sound Institute, University of Washington, Tacoma, Washington, 98402, USA
| | - Lisa K Schwarz
- Institute of Marine Sciences, University of California, Santa Cruz, California, 95064, USA
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Bröker KCA, Gailey G, Tyurneva OY, Yakovlev YM, Sychenko O, Dupont JM, Vertyankin VV, Shevtsov E, Drozdov KA. Site-fidelity and spatial movements of western North Pacific gray whales on their summer range off Sakhalin, Russia. PLoS One 2020; 15:e0236649. [PMID: 32797058 PMCID: PMC7428188 DOI: 10.1371/journal.pone.0236649] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/09/2020] [Indexed: 11/18/2022] Open
Abstract
The Western North-Pacific (WNP) gray whale feeding grounds are off the northeastern coast of Sakhalin Island, Russia and is comprised of a nearshore and offshore component that can be distinguished by both depth and location. Spatial movements of gray whales within their foraging grounds were examined based on 13 years of opportunistic vessel and shore-based photo-identification surveys. Site fidelity was assessed by examining annual return and resighting rates. Lagged Identification Rates (LIR) analyses were conducted to estimate the residency and transitional movement patterns within the two components of their feeding grounds. In total 243 individuals were identified from 2002-2014, among these were 94 calves. The annual return rate over the period 2002-2014 was 72%, excluding 35 calves only seen one year. Approximately 20% of the individuals identified from 2002-2010 were seen every year after their initial sighting (including eight individuals that returned for 13 consecutive years). The majority (239) of the WNP whales were observed in the nearshore area while only half (122) were found in the deeper offshore area. Within a foraging season, there was a significantly higher probability of gray whales moving from the nearshore to the offshore area. No mother-calf pairs, calves or yearlings were observed in the offshore area, which was increasingly used by mature animals. The annual return rates, and population growth rates that are primarily a result of calf production with little evidence of immigration, suggest that this population is demographically self-contained and that both the nearshore and offshore Sakhalin feeding grounds are critically important areas for their summer annual foraging activities. The nearshore habitat is also important for mother-calf pairs, younger individuals, and recently weaned calves. Nearshore feeding could also be energetically less costly compared to foraging in the deeper offshore habitat and provide more protection from predators, such as killer whales.
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Affiliation(s)
- Koen C. A. Bröker
- Marine Evolution and Conservation, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, the Netherlands
- Shell Global Solutions International B.V., the Hague, The Netherlands
| | - Glenn Gailey
- Cetacean EcoSystem Research, Washington, Olympia, United States of America
| | - Olga Yu. Tyurneva
- A.V. Zhirmunsky National Scientific Center of Marine Biology of the Far Eastern Branch of the Russian Academy of Sciences (NSCMB FEB RAS), Vladivostok, Russian Federation
| | - Yuri M. Yakovlev
- A.V. Zhirmunsky National Scientific Center of Marine Biology of the Far Eastern Branch of the Russian Academy of Sciences (NSCMB FEB RAS), Vladivostok, Russian Federation
| | - Olga Sychenko
- Cetacean EcoSystem Research, Washington, Olympia, United States of America
| | - Jennifer M. Dupont
- ExxonMobil Upstream Research Company, Houston, Texas, United States of America
| | | | - Evgeny Shevtsov
- A.V. Zhirmunsky National Scientific Center of Marine Biology of the Far Eastern Branch of the Russian Academy of Sciences (NSCMB FEB RAS), Vladivostok, Russian Federation
| | - Konstantin A. Drozdov
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry of the Far Eastern Branch of the Russian Academy of Sciences (PIBOC FEB RAS), Vladivostok, Russian Federation
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Gailey G, Sychenko O, Tyurneva O, Yakovlev Y, Vertyankin V, van der Wolf P, Drozdov K, Zhmaev I. Effects of sea ice on growth rates of an endangered population of gray whales. Sci Rep 2020; 10:1553. [PMID: 32005947 PMCID: PMC6994479 DOI: 10.1038/s41598-020-58435-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Accepted: 01/10/2020] [Indexed: 11/15/2022] Open
Abstract
The western gray whale population is endangered with approximately 175 individuals and 33 known reproductive females. Photo-identification studies were conducted from 2002–2017 during the gray whale foraging season off northeastern Sakhalin Island, Russia. Despite abundant prey resources, significant variation in whales’ body condition, inter-birth intervals and calf survival have been documented with limited understanding of factors that account for the observed variability. We examine sea ice concentrations at their known foraging grounds to define the maximum duration of a “foraging season”. We explore the relationship between foraging season length during a female’s pregnancy and post-weaning calf survival and reproduction. Approximately 77% of the variation in calf survival, which ranged annually from 10–80%, was associated with the duration of the feeding season while the mother was pregnant. Poor body conditions and prolonged inter-birth intervals of western gray whales have also been documented to coincide with shorter duration in feeding seasons found in this study. These results imply that shorter foraging seasons are associated with reduced energy intake by physically limiting the number of days gray whales can forage, and thus sea ice conditions may be one limiting factor affecting growth rates of this endangered population of baleen whales.
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Affiliation(s)
- G Gailey
- Cetacean EcoSystem Research, Olympia, WA, USA.
| | - O Sychenko
- Cetacean EcoSystem Research, Olympia, WA, USA
| | - O Tyurneva
- National Science Center of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok, Russia
| | - Y Yakovlev
- National Science Center of Marine Biology, Far East Branch, Russian Academy of Sciences, Vladivostok, Russia
| | - V Vertyankin
- Kronotsky State Biosphere Reserve, Elizovo, Russia
| | - P van der Wolf
- Consultant to Sakhalin Energy Investment Company, Yuzhno-Sakhalinsk, Russia
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Villegas-Amtmann S, Schwarz LK, Gailey G, Sychenko O, Costa DP. East or west: the energetic cost of being a gray whale and the consequence of losing energy to disturbance. ENDANGER SPECIES RES 2017. [DOI: 10.3354/esr00843] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Gailey G, Sychenko O, McDonald T, Racca R, Rutenko A, Bröker K. Behavioural responses of western gray whales to a 4-D seismic survey off northeastern Sakhalin Island, Russia. ENDANGER SPECIES RES 2016. [DOI: 10.3354/esr00713] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Muir JE, Ainsworth L, Racca R, Bychkov Y, Gailey G, Vladimirov V, Starodymov S, Bröker K. Gray whale densities during a seismic survey off Sakhalin Island, Russia. ENDANGER SPECIES RES 2016. [DOI: 10.3354/esr00709] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Muir JE, Ainsworth L, Joy R, Racca R, Bychkov Y, Gailey G, Vladimirov V, Starodymov S, Bröker K. Distance from shore as an indicator of disturbance of gray whales during a seismic survey off Sakhalin Island, Russia. ENDANGER SPECIES RES 2015. [DOI: 10.3354/esr00701] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Muir JE, Joy R, Bychkov Y, Bröker K, Gailey G, Vladmirov V, Starodymov S, Yakovlev Y. Delineation of a coastal gray whale feeding area using opportunistic and systematic survey effort. ENDANGER SPECIES RES 2015. [DOI: 10.3354/esr00705] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Karczmarski L, Huang SL, Or CKM, Gui D, Chan SCY, Lin W, Porter L, Wong WH, Zheng R, Ho YW, Chui SYS, Tiongson AJC, Mo Y, Chang WL, Kwok JHW, Tang RWK, Lee ATL, Yiu SW, Keith M, Gailey G, Wu Y. Humpback Dolphins in Hong Kong and the Pearl River Delta: Status, Threats and Conservation Challenges. Adv Mar Biol 2015; 73:27-64. [PMID: 26790887 DOI: 10.1016/bs.amb.2015.09.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In coastal waters of the Pearl River Delta (PRD) region, the Indo-Pacific humpback dolphin (Sousa chinensis) is thought to number approximately 2500 individuals. Given these figures, the putative PRD population may appear strong enough to resist demographic stochasticity and environmental pressures. However, living in close proximity to the world's busiest seaport/airport and several densely populated urban centres with major coastal infrastructural developments comes with challenges to the long-term survival of these animals. There are few other small cetacean populations that face the range and intensity of human-induced pressures as those present in the PRD and current protection measures are severely inadequate. Recent mark-recapture analyses of the animals in Hong Kong waters indicate that in the past two decades the population parameters have not been well understood, and spatial analyses show that only a very small proportion of the dolphins' key habitats are given any form of protection. All current marine protected areas within the PRD fail to meet a minimum habitat requirement that could facilitate the population's long-term persistence. Demographic models indicate a continuous decline of 2.5% per annum, a rate at which the population is likely to drop below the demographic threshold within two generations and lose 74% of the current numbers within the lifespan of three generations. In Hong Kong, the case of humpback dolphins represents a particularly explicit example of inadequate management where a complete revision of the fundamental approach to conservation management is urgently needed.
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Affiliation(s)
- Leszek Karczmarski
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong.
| | - Shiang-Lin Huang
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Carmen K M Or
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Duan Gui
- South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Marine Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Stephen C Y Chan
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Wenzhi Lin
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Marine Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Lindsay Porter
- SMRU Asia Pacific, The University of St. Andrews, St. Andrews, Scotland, United Kingdom
| | - Wai-Ho Wong
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Ruiqiang Zheng
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong; South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Marine Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Yuen-Wa Ho
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Scott Y S Chui
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Angelico Jose C Tiongson
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Yaqian Mo
- South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Marine Sciences, Sun Yat-Sen University, Guangzhou, PR China
| | - Wei-Lun Chang
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - John H W Kwok
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Ricky W K Tang
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Andy T L Lee
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Sze-Wing Yiu
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong
| | - Mark Keith
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong; Centre for Wildlife Management, University of Pretoria, Pretoria, South Africa
| | - Glenn Gailey
- The Swire Institute of Marine Science and School of Biological Sciences, The University of Hong Kong, Cape d'Aguilar, Shek O, Hong Kong; Cascadia Research Collective, Olympia, Washington, USA
| | - Yuping Wu
- South China Sea Bio-Resource Exploitation and Utilization Collaborative Innovation Center, School of Marine Sciences, Sun Yat-Sen University, Guangzhou, PR China.
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Bröker K, Gailey G, Muir J, Racca R. Monitoring and impact mitigation during a 4D seismic survey near a population of gray whales off Sakhalin Island, Russia. ENDANGER SPECIES RES 2015. [DOI: 10.3354/esr00670] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Johnson SR, Richardson WJ, Yazvenko SB, Blokhin SA, Gailey G, Jenkerson MR, Meier SK, Melton HR, Newcomer MW, Perlov AS, Rutenko SA, Würsig B, Martin CR, Egging DE. A western gray whale mitigation and monitoring program for a 3-D seismic survey, Sakhalin Island, Russia. Environ Monit Assess 2007; 134:1-19. [PMID: 17657576 PMCID: PMC2798040 DOI: 10.1007/s10661-007-9813-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Accepted: 03/29/2007] [Indexed: 05/16/2023]
Abstract
The introduction of anthropogenic sounds into the marine environment can impact some marine mammals. Impacts can be greatly reduced if appropriate mitigation measures and monitoring are implemented. This paper concerns such measures undertaken by Exxon Neftegas Limited, as operator of the Sakhalin-1 Consortium, during the Odoptu 3-D seismic survey conducted during 17 August-9 September 2001. The key environmental issue was protection of the critically endangered western gray whale (Eschrichtius robustus), which feeds in summer and fall primarily in the Piltun feeding area off northeast Sakhalin Island. Existing mitigation and monitoring practices for seismic surveys in other jurisdictions were evaluated to identify best practices for reducing impacts on feeding activity by western gray whales. Two buffer zones were established to protect whales from physical injury or undue disturbance during feeding. A 1 km buffer protected all whales from exposure to levels of sound energy potentially capable of producing physical injury. A 4-5 km buffer was established to avoid displacing western gray whales from feeding areas. Trained Marine Mammal Observers (MMOs) on the seismic ship Nordic Explorer had the authority to shut down the air guns if whales were sighted within these buffers. Additional mitigation measures were also incorporated: Temporal mitigation was provided by rescheduling the program from June-August to August-September to avoid interference with spring arrival of migrating gray whales. The survey area was reduced by 19% to avoid certain waters <20 m deep where feeding whales concentrated and where seismic acquisition was a lower priority. The number of air guns and total volume of the air guns were reduced by about half (from 28 to 14 air guns and from 3,390 in(3) to 1,640 in(3)) relative to initial plans. "Ramp-up" (="soft-start") procedures were implemented. Monitoring activities were conducted as needed to implement some mitigation measures, and to assess residual impacts. Aerial and vessel-based surveys determined the distribution of whales before, during and after the seismic survey. Daily aerial reconnaissance helped verify whale-free areas and select the sequence of seismic lines to be surveyed. A scout vessel with MMOs aboard was positioned 4 km shoreward of the active seismic vessel to provide better visual coverage of the 4-5 km buffer and to help define the inshore edge of the 4-5 km buffer. A second scout vessel remained near the seismic vessel. Shore-based observers determined whale numbers, distribution, and behavior during and after the seismic survey. Acoustic monitoring documented received sound levels near and in the main whale feeding area. Statistical analyses of aerial survey data indicated that about 5-10 gray whales moved away from waters near (inshore of) the seismic survey during seismic operations. They shifted into the core gray whale feeding area farther south, and the proportion of gray whales observed feeding did not change over the study period. Five shutdowns of the air guns were invoked for gray whales seen within or near the buffer. A previously unknown gray whale feeding area (the Offshore feeding area) was discovered south and offshore from the nearshore Piltun feeding area. The Offshore area has subsequently been shown to be used by feeding gray whales during several years when no anthropogenic activity occurred near the Piltun feeding area.Shore-based counts indicated that whales continued to feed inshore of the Odoptu block throughout the seismic survey, with no significant correlation between gray whale abundance and seismic activity. Average values of most behavioral parameters were similar to those without seismic surveys. Univariate analysis showed no correlation between seismic sound levels and any behavioral parameter. Multiple regression analyses indicated that, after allowance for environmental covariates, 5 of 11 behavioral parameters were statistically correlated with estimated seismic survey-related variables; 6 of 11 behavioral parameters were not statistically correlated with seismic survey-related variables. Behavioral parameters that were correlated with seismic variables were transient and within the range of variation attributable to environmental effects. Acoustic monitoring determined that the 4-5 km buffer zone, in conjunction with reduction of the air gun array to 14 guns and 1,640 in(3), was effective in limiting sound exposure. Within the Piltun feeding area, these mitigation measures were designed to insure that western gray whales were not exposed to received levels exceeding the 163 dB re 1 microPa (rms) threshold. This was among the most complex and intensive mitigation programs ever conducted for any marine mammal. It provided valuable new information about underwater sounds and gray whale responses during a nearshore seismic program that will be useful in planning future work. Overall, the efforts in 2001 were successful in reducing impacts to levels tolerable by western gray whales. Research in 2002-2005 suggested no biologically significant or population-level impacts of the 2001 seismic survey.
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Affiliation(s)
- S R Johnson
- LGL Limited, Environmental Research Associates, 9768 Second Street, Sidney, BC, V8L 3Y8, Canada.
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Gailey G, Würsig B, McDonald TL. Abundance, behavior, and movement patterns of western gray whales in relation to a 3-D seismic survey, Northeast Sakhalin Island, Russia. Environ Monit Assess 2007; 134:75-91. [PMID: 17616825 PMCID: PMC2798038 DOI: 10.1007/s10661-007-9812-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2006] [Accepted: 03/30/2007] [Indexed: 05/16/2023]
Abstract
A geophysical seismic survey was conducted in the summer of 2001 off the northeastern coast of Sakhalin Island, Russia. The area of seismic exploration was immediately adjacent to the Piltun feeding grounds of the endangered western gray whale (Eschrichtius robustus). This study investigates relative abundance, behavior, and movement patterns of gray whales in relation to occurrence and proximity to the seismic survey by employing scan sampling, focal follow, and theodolite tracking methodologies. These data were analyzed in relation to temporal, environmental, and seismic related variables to evaluate potential disturbance reactions of gray whales to the seismic survey. The relative numbers of whales and pods recorded from five shore-based stations were not significantly different during periods when seismic surveys were occurring compared to periods when no seismic surveys were occurring and to the post-seismic period. Univariate analyses indicated no significant statistical correlation between seismic survey variables and any of the eleven movement and behavior variables. Multiple regression analyses indicated that, after accounting for temporal and environmental variables, 6 of 11 movement and behavior variables (linearity, acceleration, mean direction, blows per surfacing, and surface-dive blow rate) were not significantly associated with seismic survey variables, and 5 of 11 variables (leg speed, reorientation rate, distance-from-shore, blow interval, and dive time) were significantly associated with seismic survey variables. In summary, after accounting for environmental variables, no correlation was found between seismic survey variables and the linearity of whale movements, changes in whale swimming speed between theodolite fixes, mean direction of whale movement, mean number of whale exhalations per minute at the surface, mean time at the surface, and mean number of exhalations per minute during a whales surface-to-dive cycle. In contrast, at higher received sound energy exposure levels, whales traveled faster, changed directions of movement less, were recorded further from shore, and stayed under water longer between respirations.
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Affiliation(s)
- Glenn Gailey
- Marine Mammal Research Program, Texas A&M University at Galveston, 4700 Avenue U Building 303, Galveston, TX 77551, USA.
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Karczmarski L, Würsig B, Gailey G, Larson KW, Vanderlip C. Spinner dolphins in a remote Hawaiian atoll: social grouping and population structure. Behav Ecol 2005. [DOI: 10.1093/beheco/ari028] [Citation(s) in RCA: 113] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Gailey G. "Vice-versa". J Inst Sterile Serv Manage 1989; 1:14-6. [PMID: 10303562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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