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Streever B. Western gray whales and seismic operations: an introduction to the topical selection and a tribute to the late Rodger Melton. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:747. [PMID: 36255500 PMCID: PMC9579062 DOI: 10.1007/s10661-022-10056-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Affiliation(s)
- Bill Streever
- S/V Rocinante, 3824 Cedar Springs Rd 801-2771, Dallas, TX, USA.
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2
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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. ENVIRONMENTAL MONITORING AND ASSESSMENT 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] [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. ENVIRONMENTAL MONITORING AND ASSESSMENT 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] [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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4
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Blanchard AL, Demchenko NL, Aerts LAM, Yazvenko SB, Ivin VV, Shcherbakov IA. Benthic studies adjacent to Sakhalin Island, Russia, 2015 I: benthic biomass and community structure in the nearshore gray whale feeding area. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 194:743. [PMID: 36255552 PMCID: PMC9579072 DOI: 10.1007/s10661-022-10017-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Accepted: 05/17/2021] [Indexed: 05/11/2023]
Abstract
Okhotsk or western gray whales feed in summer along the northeastern coast of Sakhalin Island, Russia, a region with oil and gas extraction facilities. Seismic surveys increased sound levels in the nearshore feeding area in 2015 for part of the summer, potentially displacing whales from preferred foraging habitat or reducing foraging efficiency. Since lost foraging opportunities might lead to vital rate effects on this endangered species, detailed benthic surveys were conducted to characterize benthic community biomass patterns and spatial and temporal differences. Benthic biomass demonstrated strong spatial-temporal interactions indicating that prey biomass differences among locations were dependent on sampling period. Of greatest interest, Amphipoda biomass declined from June to October in the northern and southern portions of the nearshore study area but increased in the middle and Actinopterygii biomass increased in the northern area in mid-summer. Water depth and sediment type were significant covariates with community structure, and water depth strongly covaried with bivalve biomass. Total average prey biomass was ~ 100 g/m2 within the nearshore feeding area with no evidence of reduced biomass among sampling periods or locations, although there were fewer amphipods in the south. Multi-prey investigations provide a stronger basis for inferences than single-prey studies of amphipods when gray whales feed on diverse prey. Benthic community-level variability was moderate to high as would be expected for a shallow-water nearshore area. Overall, spatial and temporal changes in dominant macrofauna biomass reflected small to medium-sized effects that were well within the natural boundaries expected for benthic communities.
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Affiliation(s)
| | - Natalia L Demchenko
- A.V. Zhirmunsky National Science Center of Marine Biology, Far East Branch of Russian Academy of Sciences, Vladivostok, Russia
| | | | | | - Victor V Ivin
- L.S. Berg State Research Institute On Lake and River Fisheries, Saint Petersburg, 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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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. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2021; 31:e02440. [PMID: 34374143 DOI: 10.1002/eap.2440] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [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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Blanchard AL, Demchenko NL, Aerts LAM, Yazvenko SB, Ivin VV, Shcherbakov I, Melton HR. Prey biomass dynamics in gray whale feeding areas adjacent to northeastern Sakhalin (the Sea of Okhotsk), Russia, 2001-2015. MARINE ENVIRONMENTAL RESEARCH 2019; 145:123-136. [PMID: 30851949 DOI: 10.1016/j.marenvres.2019.02.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/11/2019] [Accepted: 02/17/2019] [Indexed: 05/25/2023]
Abstract
Changing climate patterns strongly influence marine ecosystems across the Pacific Arctic region creating significant ecosystem transitions and change. Macrobenthic species are essential prey for numerous marine mammals and seabirds but the influence of climatic drivers that control macrobenthic community population dynamics are poorly known in critical prey habitats. We investigated associations of environmental, temporal, and climatic covariates with the biomass concentrations of six prey groups (Actinopterygii, Amphipoda, Bivalvia, Cumacea, Isopoda, and Polychaeta) in essential habitats for Korean-Okhotsk (western) gray whales adjacent to northeastern Sakhalin Island in the Sea of Okhotsk. Prey community biomass concentrations were correlated with water depth, year, and climate indices reflecting oceanographic and climatic patterns associated with macro-scale climatological effects. The correlation of prey biomass with water depth and year accounted for ∼90% of total variation in canonical correlation analyses (CCor). Climate indices accounted for ∼10% of total variation in CCor. Water circulation in winter may be particularly important for maintaining populations through the advection of particulate organic carbon entrained in winter currents. Overall, temporal trends in the biomass concentrations of gray whale prey resources appear to reflect climatic and oceanographic factors that are driving ecosystem changes across the Sea of Okhotsk and the Pacific Arctic region.
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Affiliation(s)
| | | | | | | | - Victor V Ivin
- L.S. Berg State Research Institute on Lake and River Fisheries, Saint Petersburg, Russia
| | - Ilya Shcherbakov
- National Scientific Center of Marine Biology FEB RAS, Russia; Far Eastern Federal University, Vladivostok, Russia
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Dunlop RA, Noad MJ, McCauley RD, Kniest E, Slade R, Paton D, Cato DH. A behavioural dose-response model for migrating humpback whales and seismic air gun noise. MARINE POLLUTION BULLETIN 2018; 133:506-516. [PMID: 30041344 DOI: 10.1016/j.marpolbul.2018.06.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/29/2018] [Accepted: 06/03/2018] [Indexed: 06/08/2023]
Abstract
The behavioural responses of migrating humpback whales to an air gun, a small clustered seismic array and a commercial array were used to develop a dose-response model, accounting for the presence of the vessel, array towpath relative to the migration and social and environmental parameters. Whale groups were more likely to show an avoidance response (increasing their distance from the source) when the received sound exposure level was over 130 dB re 1 μPa2·s and they were within 4 km of the source. The 50% probability of response occurred where received levels were 150-155 dB re 1 μPa2·s and they were within 2.5 km of the source. A small number of whales moving rapidly close to the source vessel did not exhibit an avoidance response at the highest received levels (160-170 dB re 1 μPa2·s) meaning it was not possible to estimate the maximum response threshold.
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Affiliation(s)
- Rebecca A Dunlop
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia.
| | - Michael J Noad
- Cetacean Ecology and Acoustics Laboratory, School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia
| | | | - Eric Kniest
- School of Engineering, University of Newcastle, Callaghan, NSW, 2308, Australia
| | - Robert Slade
- Blue Planet Marine, P.O. Box 919, Canberra ACT 2614, Australia
| | - David Paton
- Blue Planet Marine, P.O. Box 919, Canberra ACT 2614, Australia
| | - Douglas H Cato
- School of Geosciences, University of Sydney and Defence Science and Technology Group, Sydney, NSW 2006, Australia
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Dunlop RA, Noad MJ, McCauley RD, Kniest E, Slade R, Paton D, Cato DH. The behavioural response of migrating humpback whales to a full seismic airgun array. Proc Biol Sci 2018; 284:rspb.2017.1901. [PMID: 29237853 DOI: 10.1098/rspb.2017.1901] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 11/14/2017] [Indexed: 11/12/2022] Open
Abstract
Despite concerns on the effects of noise from seismic survey airguns on marine organisms, there remains uncertainty as to the biological significance of any response. This study quantifies and interprets the response of migrating humpback whales (Megaptera novaeangliae) to a 3130 in3 (51.3l) commercial airgun array. We compare the behavioural responses to active trials (array operational; n = 34 whale groups), with responses to control trials (source vessel towing the array while silent; n = 33) and baseline studies of normal behaviour in the absence of the vessel (n = 85). No abnormal behaviours were recorded during the trials. However, in response to the active seismic array and the controls, the whales displayed changes in behaviour. Changes in respiration rate were of a similar magnitude to changes in baseline groups being joined by other animals suggesting any change group energetics was within their behavioural repertoire. However, the reduced progression southwards in response to the active treatments, for some cohorts, was below typical migratory speeds. This response was more likely to occur within 4 km from the array at received levels over 135 dB re 1 µPa2s.
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Affiliation(s)
- Rebecca A Dunlop
- School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia
| | - Michael J Noad
- School of Veterinary Science, The University of Queensland, Gatton, Queensland 4343, Australia
| | - Robert D McCauley
- Curtin University, GPO Box U 1987, Perth, Western Australia 6845, Australia
| | - Eric Kniest
- School of Engineering, University of Newcastle, Callaghan, New South Wales 2308, Australia
| | - Robert Slade
- Blue Planet Marine, PO Box 919, Canberra, Australian Capital Territory 2614, Australia
| | - David Paton
- Blue Planet Marine, PO Box 919, Canberra, Australian Capital Territory 2614, Australia
| | - Douglas H Cato
- School of Geosciences, University of Sydney and Defence Science and Technology Group, Sydney, New South Wales 2006, Australia
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Forney KA, Southall BL, Slooten E, Dawson S, Read AJ, Baird RW, Brownell RL. Nowhere to go: noise impact assessments for marine mammal populations with high site fidelity. ENDANGER SPECIES RES 2017. [DOI: 10.3354/esr00820] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Vilela R, Pena U, Esteban R, Koemans R. Bayesian spatial modeling of cetacean sightings during a seismic acquisition survey. MARINE POLLUTION BULLETIN 2016; 109:512-520. [PMID: 27210556 DOI: 10.1016/j.marpolbul.2016.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 04/29/2016] [Accepted: 05/04/2016] [Indexed: 06/05/2023]
Abstract
A visual monitoring of marine mammals was carried out during a seismic acquisition survey performed in waters south of Portugal with the aim of assessing the likelihood of encountering Mysticeti species in this region as well as to determine the impact of the seismic activity upon encounter. Sightings and effort data were assembled with a range of environmental variables at different lags, and a Bayesian site-occupancy modeling approach was used to develop prediction maps and evaluate how species-specific habitat conditions evolved throughout the presence or not of seismic activity. No statistical evidence of a decrease in the sighting rates of Mysticeti by comparison to source activity was found. Indeed, it was found how Mysticeti distribution during the survey period was driven solely by environmental variables. Although further research is needed, possible explanations may include anthropogenic noise habituation and zone of seismic activity coincident with a naturally low density area.
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Affiliation(s)
- Raul Vilela
- Wildlife Conservation Society, Africa program, Battery IV, seated CIMA, BP7847 Libreville, Gabon.
| | - Ursula Pena
- Wildlife Conservation Society, Africa program, Battery IV, seated CIMA, BP7847 Libreville, Gabon
| | - Ruth Esteban
- CIRCE (Conservation Information and Research on Cetaceans), C/Cabeza de Manzaneda 3, Pelayo-Algeciras, 11390 Cádiz, Spain
| | - Robin Koemans
- Repsol Exploracion, Méndez Álvaro, 44, 28045 Madrid, Spain
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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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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12
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Robertson FC, Koski WR, Thomas TA, Richardson WJ, Würsig B, Trites AW. Seismic operations have variable effects on dive-cycle behavior of bowhead whales in the Beaufort Sea. ENDANGER SPECIES RES 2013. [DOI: 10.3354/esr00515] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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Guo H, Pan L, Li Z, Wei N, Wang H, Xiao K, Li H. Earthquake distresses reproductive function but not fetal development in rats. BIRTH DEFECTS RESEARCH. PART B, DEVELOPMENTAL AND REPRODUCTIVE TOXICOLOGY 2012; 95:47-53. [PMID: 22140077 DOI: 10.1002/bdrb.20340] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 09/18/2011] [Accepted: 09/19/2011] [Indexed: 02/05/2023]
Abstract
BACKGROUND It is well known that earthquake severely threatens life-safety and physical damage. However, the empirical literature on the effects of nature disasters such as earthquake on the reproductive outcomes is limited. METHODS On May 12th, 2008, a massive 8.0 magnitude earthquake occurred in Wenchuan, a city 92 km away from our animal facility [National Chengdu Center for Safety Evaluation of Drugs (NCCSED)]. To investigate whether this tremendous earthquake exerted adverse effects on the reproductive and developmental functions in Sprague-Dawley rats, we collected some relevant data from reproductive toxicity studies around the earthquake, and compared them with the background data, which were gathered before and after the earthquake. Copulation ratio, gestation ratio, and fertility of female rats, as well as uterine and fetal morphology, were examined. RESULTS Our data demonstrated that the Wenchuan earthquake significantly decreased the copulation and gestation ratio, although it did not exhibit obvious side effects on some other reproductive and developmental parameters.
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Affiliation(s)
- Haidong Guo
- National Chengdu Center for Safety Evaluation of Drugs, West China Hospital, Sichuan University, Chengdu, People's Republic of China
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14
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Rutenko AN, Borisov SV, Gritsenko AV, Jenkerson MR. Calibrating and monitoring the western gray whale mitigation zone and estimating acoustic transmission during a 3D seismic survey, Sakhalin Island, Russia. ENVIRONMENTAL MONITORING AND ASSESSMENT 2007; 134:21-44. [PMID: 17762974 PMCID: PMC2798049 DOI: 10.1007/s10661-007-9814-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2006] [Accepted: 05/11/2007] [Indexed: 05/15/2023]
Abstract
A 3D marine seismic survey of the Odoptu license area off northeastern Sakhalin Island, Russia, was conducted by DalMorNefteGeofizika (DMNG) on behalf of Exxon Neftegas Limited and the Sakhalin-1 consortium during mid-August through early September 2001. The key environmental issue identified in an environmental impact assessment was protection of the critically endangered western gray whale (Eschrichtius robustus), which spends the summer-fall open water period feeding off northeast Sakhalin Island in close proximity to the seismic survey area. Seismic mitigation and monitoring guidelines and recommendations were developed and implemented to reduce impacts on the feeding activity of western gray whales. Results of the acoustic monitoring program indicated that the noise monitoring and mitigation program was successful in reducing exposure of feeding western gray whales to seismic noise.
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Affiliation(s)
- A. N. Rutenko
- Pacific Oceanological Institute (POI), Far East Branch of the Russian Academy of Sciences, 43 Baltyskaya Street, 690068 Vladivostok, Russia
| | - S. V. Borisov
- Pacific Oceanological Institute (POI), Far East Branch of the Russian Academy of Sciences, 43 Baltyskaya Street, 690068 Vladivostok, Russia
| | - A. V. Gritsenko
- Pacific Oceanological Institute (POI), Far East Branch of the Russian Academy of Sciences, 43 Baltyskaya Street, 690068 Vladivostok, Russia
| | - M. R. Jenkerson
- ExxonMobil Exploration Company, P.O. Box 4778, Houston, TX 77210-4778 USA
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15
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Yazvenko SB, McDonald TL, Blokhin SA, Johnson SR, Meier SK, Melton HR, Newcomer MW, Nielson RM, Vladimirov VL, Wainwright PW. Distribution and abundance of western gray whales during a seismic survey near Sakhalin Island, Russia. ENVIRONMENTAL MONITORING AND ASSESSMENT 2007; 134:45-73. [PMID: 17899420 PMCID: PMC2798020 DOI: 10.1007/s10661-007-9809-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Accepted: 04/20/2007] [Indexed: 05/17/2023]
Abstract
Exxon Neftegas Limited, operator of the Sakhalin-1 consortium, is developing oil and gas reserves on the continental shelf off northeast Sakhalin Island, Russia. DalMorNefteGeofizika (DMNG), on behalf of the Sakhalin-1 consortium, conducted a 3-D seismic survey of the Odoptu license area during 17 August-9 September 2001. A portion of the primary known feeding area of the endangered western gray whale (Eschrichtius robustus) is located adjacent to the seismic block. The data presented here were collected as part of daily monitoring to determine if there was any measurable effect of the seismic survey on the distribution and abundance of western gray whales. Mitigation and monitoring program included aerial surveys conducted between 19 July and 19 November using the methodology outlined by the Southern California High Energy Seismic Survey team (HESS). These surveys provided documentation of the distribution, abundance and bottom feeding activity of western gray whales in relation to seismic survey sounds. From an operations perspective, the aerial surveys provided near real-time data on the location of whales in and outside the feeding area, and documented whether whales were displaced out of an area normally used as feeding habitat. The objectives of this study were to assess (a) temporal changes in the distribution and abundance of gray whales in relation to seismic survey, and (b) the influence of seismic survey, environmental factors, and other variables on the distribution and abundance of gray whales within their preferred feeding area adjacent to Piltun Bay. Multiple regression analysis revealed a limited redistribution of gray whales southward within the Piltun feeding area when the seismic survey was fully operational. A total of five environmental and other variables unrelated to seismic survey (date and proxies of depth, sea state and visibility) and one seismic survey-related variable (seg3d, i.e., received sound energy accumulated over 3 days) had statistically significant effects on the distribution and abundance of gray whales. The distribution of two to four gray whales observed on the surface (i.e., about five to ten whales in total) has likely been affected by the seismic survey. However, the total number of gray whales observed within the Piltun feeding area remained stable during the seismic survey.
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Affiliation(s)
- S B Yazvenko
- LGL Limited, Environmental Research Associates, 9768 Second Street, Sidney, BC, V8L 3Y8, Canada.
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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. ENVIRONMENTAL MONITORING AND ASSESSMENT 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] [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. ENVIRONMENTAL MONITORING AND ASSESSMENT 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] [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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Meier SK, Yazvenko SB, Blokhin SA, Wainwright P, Maminov MK, Yakovlev YM, Newcomer MW. Distribution and abundance of western gray whales off northeastern Sakhalin Island, Russia, 2001-2003. ENVIRONMENTAL MONITORING AND ASSESSMENT 2007; 134:107-36. [PMID: 17703367 PMCID: PMC2798039 DOI: 10.1007/s10661-007-9811-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [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
In 2001-2003, >60,000 km of aerial surveys and 7,700 km of vessel surveys were conducted during June to November when critically endangered Korean-Okhotsk or western gray whales (Eschrichtius robustus) were present off the northeast coast of Sakhalin Island, Russia. Results of surveys in all years indicated gray whales occurred in predominantly two areas, (1) adjacent to Piltun Bay, and (2) offshore from Chayvo Bay, hereafter referred to as the Piltun and offshore feeding areas. In the Piltun feeding area, the majority of whales were observed in waters shallower than 20 m and were distributed from several hundred meters to approximately 5 km from the shoreline. In the offshore feeding area during all years, the distribution of gray whales extended from southwest to northeast in waters 30-65 m in depth. During all years, the distribution and abundance of whales changed in both the Piltun and offshore feeding areas, and both north-south and inshore-offshore movements were documented within and between feeding seasons. The discovery of a significant number of whales feeding in the offshore area each year was a substantial finding of this study and raises questions regarding western gray whale abundance and population levels, feeding behavior and ecology, and individual site-fidelity. Fluctuations in the number of whales observed within the Piltun and offshore feeding areas and few sightings outside of these two areas indicate that gray whales move between the Piltun and offshore feeding areas during their summer-fall feeding season. Seasonal shifts in the distribution and abundance of gray whales between and within both the Piltun and offshore feeding areas are thought, in part, to be a response to seasonal changes in the distribution and abundance of prey. However, the mechanism driving the movements of whales along the northeast coast of Sakhalin Island is likely very complex and influenced by a multitude of factors.
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Affiliation(s)
- S K Meier
- LGL Limited, Environmental Research Associates, 9768 Second Street, Sidney, BC, V8L 3Y8, Canada.
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