{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,28]],"date-time":"2026-10-28T07:17:08Z","timestamp":1793171828592,"version":"4.5.0"},"reference-count":43,"publisher":"Public Library of Science (PLoS)","issue":"3","license":[{"start":{"date-parts":[[2024,3,21]],"date-time":"2024-03-21T00:00:00Z","timestamp":1710979200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100012475","name":"Bureau of Ocean Energy Management","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100012475","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>Visual observation data collected by protected species observers (PSOs) is required per regulations stipulated in Notices to Lessees (NTLs) and geophysical survey Permits (Form BOEM-0328) issued to seismic operators in the Gulf of Mexico (GOM). Here, data collected by certified and trained PSOs during seismic surveys conducted between 2002\u20132015 were compiled and analyzed to assess utility in assessing marine mammal responses to seismic noise and effectiveness of required mitigation measures. A total of 3,886 agency-required bi-weekly PSO Effort and Sightings reports were analyzed comprising 598,319 hours of PSO visual effort and 15,117 visual sighting records of marine mammals. The observed closest point of approach (CPA) distance was statistically compared across five species groupings for four airgun activity levels (full, minimum source, ramp up, silent). Whale and dolphin detections were significantly farther from airgun array locations during full power operations versus silence, indicating some avoidance response to full-power operations. Dolphin CPA distances were also significantly farther from airguns operating at minimum source than silence. Blackfish were observed significantly farther from the airgun array during ramp up versus both full and minimum source activities. Blackfish were observed significantly closer to the airgun array during silent activities versus at full, minimum source, and ramp up activities. Beaked whales had the largest mean CPA for detection distance compared to all other species groups. Detection distances for beaked whales were not significantly differences between full and silent operations; however, the sample size was very low. Overall results are consistent with other studies indicating that marine mammals may avoid exposure to airgun sounds based on observed distance from the seismic source during specified source activities. There was geographic variability in sighting rates associated with specific areas of interest within the GOM. This study demonstrates that agency required PSO reports provide a robust and useful data set applicable to impact assessments; management, policy and regulatory decision making; and qualitative input for regional scientific, stock assessment and abundance studies. However, several improvements in content and consistency would facilitate finer-scale analysis of some topics (e.g., effort associated with specific activities, observer biases, sound field estimation) and support statistical comparisons that could provide further insight into marine mammal responses and mitigation efficacy.<\/jats:p>","DOI":"10.1371\/journal.pone.0300658","type":"journal-article","created":{"date-parts":[[2024,3,21]],"date-time":"2024-03-21T17:50:46Z","timestamp":1711043446000},"page":"e0300658","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":5,"title":["Analysis of protected species observer data: Strengths, weaknesses, and application in the assessment of marine mammal responses to seismic surveys in the northern Gulf of Mexico 2002\u20132015"],"prefix":"10.1371","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-5392-4106","authenticated-orcid":true,"given":"Mary Jo","family":"Barkaszi","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4320-165X","authenticated-orcid":true,"given":"Christopher J.","family":"Kelly","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2024,3,21]]},"reference":[{"key":"pone.0300658.ref001","unstructured":"BOEM. 2017. Gulf of Mexico OCS Proposed Geological and Geophysical Activities. Western, Central, and Eastern Planning Areas. Final Programmatic Environmental Impact Statement. OCS EIS\/EIA BOEM 2017\u2013051. New Orleans, LA."},{"key":"pone.0300658.ref002","volume-title":"Underwater sound propagation modelling to illustrate potential noise exposure to Maui dolphins from seismic surveys and vessel traffic on West Coast North IslandNew Zealand","author":"C. McPherson","year":"2019"},{"issue":"Suppl 1","key":"pone.0300658.ref003","doi-asserted-by":"crossref","first-page":"745","DOI":"10.1007\/s10661-022-10019-6","article-title":"Real-time acoustic monitoring with telemetry to mitigate potential effects of seismic survey sounds on marine mammals: a case study offshore Sakhalin Island","volume":"194","author":"A.N. Rutenko","year":"2022","journal-title":"Environmental Monitoring and Assessment"},{"issue":"2","key":"pone.0300658.ref004","article-title":"Three-dimensional propagation of seismic airgun signals in the Mississippi Canyon area of the Gulf of Mexico","volume":"1","author":"Y.T. Lin","year":"2021","journal-title":"JASA Express Letters"},{"key":"pone.0300658.ref005","unstructured":"National Marine Fisheries Service (NMFS). 2018. 2018 Revisions to: Technical Guidance for Assessing the Effects of Anthropogenic Sound on Marine Mammal Hearing (Version 2.0): Underwater Thresholds for Onset of Permanent and Temporary Threshold Shifts. U.S. Department of Commerce, National Oceanic and Atmospheric Administration. NOAA Technical Memorandum NMFS-OPR-59. 167 pp"},{"key":"pone.0300658.ref006","unstructured":"National Marine Fisheries Service (NMFS). 2023. National Marine Fisheries Service: Summary of Endangered Species Act Acoustic Thresholds (Marine Mammals, Fishes, and Sea Turtles). Available at https:\/\/www.fisheries.noaa.gov\/s3\/2023-02\/ESA%20all%20species%20threshold%20summary_508_OPR1.pdf Accessed 1 September 2023."},{"key":"pone.0300658.ref007","volume-title":"ASA S3\/SC1. 4 TR-2014 sound exposure guidelines for fishes and sea turtles: a technical report prepared by ANSI-accredited standards committee S3\/SC1 and registered with ANSI","author":"A.N. Popper","year":"2014"},{"key":"pone.0300658.ref008","volume-title":"Gulf of Mexico Marine Assessment Program for Protected Species: Marine Mammals","author":"G Rappucci"},{"key":"pone.0300658.ref009","unstructured":"Hayes, S.A., E. Josephson, K. Maze-Foley, P.E. Rosel, and J. Wallace. 2022. U.S. Atlantic and Gulf of Mexico marine mammal stock assessments\u2013 2021. Woods Hole (MA): U.S. Department of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Northeast Fisheries Science Center. Report No. NOAA Technical Memorandum NMFS-NE-288. 387 p."},{"key":"pone.0300658.ref010","first-page":"2019","volume-title":"Seismic survey mitigation measures and protected species observer reports: synthesis report","author":"M.J. Barkaszi","year":"2018"},{"key":"pone.0300658.ref011","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1016\/j.marpol.2007.05.005","article-title":"A critical examination of worldwide guidelines for minimizing the disturbance to marine mammals during seismic surveys","volume":"32","author":"R Compton","year":"2008","journal-title":"Marine Policy"},{"issue":"1","key":"pone.0300658.ref012","doi-asserted-by":"crossref","first-page":"231","DOI":"10.1016\/j.marpolbul.2015.08.045","article-title":"JNCC guidelines for minimising the risk of injury and disturbance to marine mammals from seismic surveys: We can do better","volume":"100","author":"A.J. Wright","year":"2015","journal-title":"Marine Pollution Bulletin"},{"key":"pone.0300658.ref013","unstructured":"Stone CJ. 2015. Marine mammal observations during seismic surveys from 1994\u20132010. JNCC Report No. 463a. 64 pp."},{"issue":"3","key":"pone.0300658.ref014","doi-asserted-by":"crossref","first-page":"187","DOI":"10.3354\/esr00670","article-title":"Monitoring and impact mitigation during a 4D seismic survey near a population of gray whales off Sakhalin Island, Russia","volume":"28","author":"K Br\u00f6ker","year":"2015","journal-title":"Endangered Species Research"},{"issue":"1","key":"pone.0300658.ref015","doi-asserted-by":"crossref","first-page":"72","DOI":"10.1016\/j.marpolbul.2015.12.044","article-title":"Response of humpback whales (Megaptera novaeangliae) to ramp up of a small experimental airgun array","volume":"103","author":"RA Dunlop","year":"2016","journal-title":"Marine pollution bulletin"},{"issue":"4","key":"pone.0300658.ref016","doi-asserted-by":"crossref","first-page":"356","DOI":"10.1578\/AM.39.4.2013.356","article-title":"Responsible practices for minimizing and monitoring environmental impacts of marine seismic surveys with an emphasis on marine mammals","volume":"39","author":"DP Nowacek","year":"2013","journal-title":"Aquatic Mammals"},{"key":"pone.0300658.ref017","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.marpolbul.2017.10.034","article-title":"Comparing methods suitable for monitoring marine mammals in low visibility conditions during seismic surveys","volume":"126","author":"UK Verfuss","year":"2018","journal-title":"Marine Pollution Bulletin"},{"issue":"2","key":"pone.0300658.ref018","doi-asserted-by":"crossref","first-page":"599","DOI":"10.15517\/rbt.v65i2.25477","article-title":"Cetacean sightings and acoustic detections during a seismic survey off Nicaragua and Costa Rica, November-December 2004","volume":"65","author":"M Holst","year":"2017","journal-title":"Revista de Biolog\u00eda Tropical"},{"key":"pone.0300658.ref019","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1007\/978-1-4939-2981-8_79","volume-title":"The Effects of Noise on Aquatic Life II","author":"S Ludwig","year":"2016"},{"key":"pone.0300658.ref020","doi-asserted-by":"crossref","first-page":"113","DOI":"10.1007\/978-3-319-56985-7_5","volume-title":"Advances in Marine Vertebrate Research in Latin America","author":"A Andriolo","year":"2018"},{"issue":"4","key":"pone.0300658.ref021","doi-asserted-by":"crossref","first-page":"2216","DOI":"10.1121\/1.4900043","article-title":"Strawman outline for a standard on the use of passive acoustic towed arrays for marine mammal monitoring and mitigation","volume":"136","author":"A Thode","year":"2014","journal-title":"The Journal of the Acoustical Society of America"},{"issue":"3","key":"pone.0300658.ref022","doi-asserted-by":"crossref","first-page":"239","DOI":"10.47536\/jcrm.v7i3.734","article-title":"Mitigating, monitoring and assessing the effects of anthropogenic sound on beaked whales","volume":"7","author":"J Barlow","year":"2006","journal-title":"J. Cetacean Res. Manage"},{"issue":"3","key":"pone.0300658.ref023","doi-asserted-by":"crossref","first-page":"923","DOI":"10.1111\/mms.12205","article-title":"Inferring trackline detection probabilities, g(0), for cetaceans from apparent densities in different survey conditions","volume":"31","author":"J. Barlow","year":"2015","journal-title":"Marine Mammal Science"},{"key":"pone.0300658.ref024","author":"L. Garrison","year":"2016","journal-title":"2020. Abundance of marine mammals in waters of the US southeastern Atlantic during summer"},{"key":"pone.0300658.ref025","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1017\/S0025315407055154","article-title":"Methods for investigating measurement error in cetacean line-transect surveys","volume":"87","author":"R Williams","year":"2007","journal-title":"Journal of the Marine Biological Association of the United Kingdom"},{"issue":"4","key":"pone.0300658.ref026","doi-asserted-by":"crossref","first-page":"41","DOI":"10.4031\/002533203787537087","article-title":"Controlled exposure experiments to determine the effects of noise on marine mammals","volume":"37","author":"P Tyack","year":"2003","journal-title":"Marine Technology Society Journal"},{"key":"pone.0300658.ref027","doi-asserted-by":"crossref","first-page":"55","DOI":"10.3354\/meps08255","article-title":"Studying the behaviour and sensory ecology of marine mammals using acoustic recording tags: a review","volume":"395","author":"M Johnson","year":"2009","journal-title":"Marine Ecology Progress Series"},{"issue":"4","key":"pone.0300658.ref028","doi-asserted-by":"crossref","first-page":"446","DOI":"10.1578\/AM.33.4.2007.446","article-title":"Criteria for behavioral disturbance","volume":"33","author":"BL Southall","year":"2007","journal-title":"Aquatic Mammals"},{"issue":"4","key":"pone.0300658.ref029","doi-asserted-by":"crossref","first-page":"16","DOI":"10.4031\/002533203787536998","article-title":"A review of the effects of seismic surveys on marine mammals","volume":"37","author":"J Gordon","year":"2003","journal-title":"Marine Technology Society Journal"},{"issue":"5","key":"pone.0300658.ref030","doi-asserted-by":"crossref","first-page":"421","DOI":"10.1578\/AM.47.5.2021.421","article-title":"Marine mammal noise exposure criteria: assessing the severity of marine mammal behavioral responses to human noise","volume":"47","author":"B.L. Southall","year":"2021","journal-title":"Aquatic Mammals"},{"key":"pone.0300658.ref031","unstructured":"Malme CI, Miles PR, Clark CW, Tyack P, Bird JE. 1984. Investigations of the potential effects of underwater noise from petroleum industry activities on migrating gray whale behavior. Report of Bolt Beranek & Newman, Inc., Cambridge, MA, to U.S. Minerals Management Service, Anchorage. NTIS PB86-174174."},{"key":"pone.0300658.ref032","doi-asserted-by":"crossref","first-page":"692","DOI":"10.1071\/AJ99048","article-title":"Marine seismic surveys-a study of environmental implications","volume":"40","author":"RD McCauley","year":"2000","journal-title":"APPEA J"},{"issue":"3","key":"pone.0300658.ref033","doi-asserted-by":"crossref","first-page":"255","DOI":"10.47536\/jcrm.v8i3.721","article-title":"The effects of seismic airguns on cetaceans in UK waters","volume":"8","author":"CJ Stone","year":"2006","journal-title":"J. Cetacean Res. Manage"},{"issue":"3","key":"pone.0300658.ref034","first-page":"231","article-title":"Male sperm whale behaviour during exposures to distant seismic survey pulses","volume":"28","author":"PT Madsen","year":"2002","journal-title":"Aquatic Mammals"},{"issue":"1869","key":"pone.0300658.ref035","doi-asserted-by":"crossref","DOI":"10.1098\/rspb.2017.1901","article-title":"The behavioural response of migrating humpback whales to a full seismic airgun array","volume":"284","author":"RA Dunlop","year":"2017a","journal-title":"Proc. R. Soc. B"},{"key":"pone.0300658.ref036","volume-title":"PG&E offshore 3\u2010D Seismic Survey Project EIR\u2013Marine Mammal Technical Draft Report","author":"J Wood","year":"2012"},{"issue":"16","key":"pone.0300658.ref037","doi-asserted-by":"crossref","first-page":"2878","DOI":"10.1242\/jeb.160192","article-title":"Determining the behavioural dose-response relationship of marine mammals to airgun noise and source proximity","volume":"220","author":"RA Dunlop","year":"2017b","journal-title":"Journal of Experimental Biology"},{"key":"pone.0300658.ref038","volume-title":"Sperm whale seismic study in the Gulf of Mexico Synthesis Report","author":"A Jochens","year":"2008"},{"issue":"22","key":"pone.0300658.ref039","doi-asserted-by":"crossref","first-page":"4150","DOI":"10.1242\/jeb.161232","article-title":"Lack of behavioural responses of humpack whales (Megaptera novaeangliae) indicate limited effectiveness of sonar mitigation","volume":"220","author":"PJ Wensveen","year":"2017","journal-title":"Journal of Experimental Biology"},{"key":"pone.0300658.ref040","doi-asserted-by":"crossref","first-page":"263","DOI":"10.3354\/meps265263","article-title":"Behavioural reactions of free-ranging porpoises and seals to the noise of a simulated 2 MW windpower generator","volume":"265","author":"S Koschinski","year":"2003","journal-title":"Marine Ecology Progress Series"},{"key":"pone.0300658.ref041","doi-asserted-by":"crossref","first-page":"177","DOI":"10.47536\/jcrm.v7i3.729","article-title":"Understanding the impacts of anthropogenic sound on beaked whales","volume":"7","author":"TM Cox","year":"2006","journal-title":"J. Cetacean Res. Manag"},{"key":"pone.0300658.ref042","doi-asserted-by":"crossref","first-page":"e42535","DOI":"10.1371\/journal.pone.0042535","article-title":"Vessel noise affects beaked whale behavior: results of a dedicated acoustic response study","volume":"7","author":"E Pirotta","year":"2012","journal-title":"PLoS ONE"},{"issue":"14","key":"pone.0300658.ref043","doi-asserted-by":"crossref","first-page":"2409","DOI":"10.1242\/jeb.054338","article-title":"Audiogram of a stranded Blainville\u2019s beaked whale (Mesoplodon densirostris) measured using auditory evoked potentials","volume":"214","author":"A.F. Pacini","year":"2011","journal-title":"Journal of Experimental Biology"}],"container-title":["PLOS ONE"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0300658","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,3,21]],"date-time":"2024-03-21T17:51:13Z","timestamp":1711043473000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0300658"}},"subtitle":[],"editor":[{"given":"Antonio","family":"Medina Guerrero","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2024,3,21]]},"references-count":43,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2024,3,21]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0300658","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2024,3,21]]}}}