Assessing cetacean encounter risk in offshore racing
Abstract
Large cetaceans face several anthropogenic threats. Among these, collisions are a major cause of anthropogenic mortality. Assessing and limiting their impact on populations is essential, as these species play an essential ecological role. All types of vessels, including offshore racing vessels, can collide with cetaceans. When a collision occurs between an offshore racing vessel and a large cetacean, the consequences are severe for both the whale, which is often injured or even killed and the vessel, which can suffer severe damage and be forced to withdraw from the race. Our study aimed to develop an encounter model that takes the characteristics of both cetaceans and racing vessels into account to estimate the number of encounters along vessel routes. The model was applied to three different routes commonly used in offshore racing: the first between Newport, USA and Skagen, Denmark; the second between Dover, England and the Gibraltar Strait; and the third between the Gibraltar Strait and Genoa, Italy. The number of encounters was estimated to be 1.7 for Route 1, 4.1 for Route 2 and 2.6 for Route 3. The model was also used to estimate the impact of routing vessels away from any exclusion zones that may be established in areas of high cetacean abundance. This routing could significantly reduce the number of encounters and offer potential solutions to reduce collisions between cetaceans and all types of vessels. The issue of collisions is becoming increasingly important and requires the development of methods to reduce the number of collisions worldwide.
Data availability
Vessel tracks were simulated using the qtVlm navigation software (©Meltemus 2017 - 2024, https://www.meltemus.com/), which is an open-access software, but the polars used were provided by Bañulsdesign and are confidential. Cetacean densities in the western Atlantic Ocean are publicly available at https://seamap.env.duke.edu/models/Duke/EC/. Cetacean densities near Iceland are not publicly available and should be requested from the North Atlantic Marine Mammal Commission (NAMMCO). Cetacean densities in the Northeast Atlantic Ocean are not publicly available and should be requested from the Direction Générale de l’Armement Techniques Navales. The corresponding author can provide contact details.
References
Blair, H. B., Merchant, N. D., Friedlaender, A. S., Wiley, D. N. & Parks, S. E. Evidence for ship noise impacts on humpback whale foraging behaviour. Biol. Lett. 12, 20160005. https://doi.org/10.1098/rsbl.2016.0005 (2016).
Unger, B. et al. Large amounts of marine debris found in sperm whales stranded along the North Sea coast in early 2016. Mar. Pollut. Bull. 112, 134–141. https://doi.org/10.1016/j.marpolbul.2016.08.027 (2016).
Moore, M. J. How we can all stop killing whales: a proposal to avoid whale entanglement in fishing gear. ICES J. Mar. Sci. 76, 781–786. https://doi.org/10.1093/icesjms/fsy194 (2019).
Conn, P. B. & Silber, G. K. Vessel speed restrictions reduce risk of collision-related mortality for North Atlantic right whales. Ecosphere 4, art43, https://doi.org/10.1890/ES13-00004.1 (2013).
Rockwood, R. C., Calambokidis, J. & Jahncke, J. High mortality of blue, humpback and fin whales from modeling of vessel collisions on the U.S. west coast suggests population impacts and insufficient protection. PloS one 12, e0183052. https://doi.org/10.1371/journal.pone.0183052 (2017).
Sèbe, M. et al. Estimating the impact of ship strikes on the Mediterranean fin whale subpopulation. Ocean Coast. Manag. 237, 106485. https://doi.org/10.1016/j.ocecoaman.2023.106485 (2023).
Read, A. J., Drinker, P. & Northridge, S. Bycatch of marine mammals in U.S. and global fisheries. Conserv. Biol. 20, 163–169, https://doi.org/10.1111/j.1523-1739.2006.00338.x (2006).
Tulloch, V. et al. Long-term trends and a risk analysis of cetacean entanglements and bycatch in fisheries gear in Australian waters. Biodivers. Conserv. 29, 251–282. https://doi.org/10.1007/s10531-019-01881-x (2020).
Pirotta, V., Grech, A., Jonsen, I. D., Laurance, W. F. & Harcourt, R. G. Consequences of global shipping traffic for marine giants. Front. Ecol. Environ. 17, 39–47. https://doi.org/10.1002/fee.1987 (2019).
Doughty, C. E. et al. Global nutrient transport in a world of giants. Proc. Natl. Acad. Sci. 113, 868–873. https://doi.org/10.1073/pnas.1502549112 (2016).
Wiggins, S. M., Thayre, B. J., Trickey, J. S., Baumann-Pickering, S. & Hildebrand, J. A. Beaked whale passive acoustic tracking offshore of Cape Hatteras 2017. Tech. Rep., Marine Physical Laboratory, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, MPL Technical Memorandum 631 October 2018. Submitted to Naval Facilities Engineering Command (NAVFAC) Atlantic, Norfolk, Virginia, under Contract No. N62470-15-D-8006 Subcontract 383-8476 (MSA2015-1176 Task Order 003) issued to HDR, Inc. (2018).
Baumgartner, M. F., Wenzel, F. W., Lysiak, N. S. & Patrician, M. R. North Atlantic right whale foraging ecology and its role in human-caused mortality. Mar. Ecol. Prog. Ser. 581, 165–181. https://doi.org/10.3354/meps12315 (2017).
Calambokidis, J. et al. Differential vulnerability to ship strikes between day and night for blue, fin, and humpback whales based on dive and movement data from medium duration archival tags. Front. Mar. Sci. 6, https://doi.org/10.3389/fmars.2019.00543 (2019).
Keen, E. M. et al. Night and day: Diel differences in ship strike risk for fin whales (Balaenoptera physalus) in the California current system. Front. Mar. Sci. 6, https://doi.org/10.3389/fmars.2019.00730 (2019).
Smith, J. N. et al. Quantifying ship strike risk to breeding whales in a multiple-use marine park: the Great Barrier Reef. Front. Mar. Sci. 7, 67. https://doi.org/10.3389/fmars.2020.00067 (2020).
Ritter, F. & Panigada, S. Chapter 28 - Collisions of vessels with cetaceans – The underestimated threat. In Sheppard, C. (ed.) World Seas: An Environmental Evaluation (Second Edition), 531–547, https://doi.org/10.1016/B978-0-12-805052-1.00026-7 (Academic Press, 2019), second edition edn.
Laist, D. W., Knowlton, A. R., Mead, J. G., Collet, A. S. & Podesta, M. Collisions between ships and whales. Mar. Mammal Sci. 17, 35–75. https://doi.org/10.1111/j.1748-7692.2001.tb00980.x (2001).
Vanderlaan, A. S. M. & Taggart, C. T. Vessel collisions with whales: the probability of injury based on vessel speed. Mar. Mammal Sci. 23, 144–156. https://doi.org/10.1111/j.1748-7692.2006.00098.x (2007).
Garrison, L. P. et al. The effects of vessel speed and size on the lethality of strikes of large whales in us waters. Front. Mar. Sci. 11, 1467387. https://doi.org/10.3389/fmars.2024.1467387 (2025).
Peltier, H. et al. Monitoring of marine mammal strandings along French coasts reveals the importance of ship strikes on large cetaceans: A challenge for the European marine strategy framework directive. Front. Mar. Sci. 6, https://doi.org/10.3389/fmars.2019.00486 (2019).
Winkler, C., Panigada, S., Murphy, S. & Ritter, F. Global numbers of ship strikes: An assessment of collisions between vessels and cetaceans using available data in the IWC ship strike database. IWC B (2020).
Ritter, F. Collisions of sailing vessels with cetaceans worldwide: First insights into a seemingly growing problem. J. Cetacean Res. Manage. 12, 119–127, https://doi.org/10.47536/jcrm.v12i1.598 (2012).
Schoeman, R. P., Patterson-Abrolat, C. & Plön, S. A global review of vessel collisions with marine animals. Front. Mar. Sci. 7, https://doi.org/10.3389/fmars.2020.00292 (2020).
Martin, J. et al. A quantitative framework for investigating risk of deadly collisions between marine wildlife and boats. Methods Ecol. Evol. 7, 42–50. https://doi.org/10.1111/2041-210X.12447 (2015).
Nowacek, D. P., Johnson, M. P. & Tyack, P. L. North Atlantic right whales (Eubalaena glacialis) ignore ships but respond to alerting stimuli. Proc. Royal Soc. London. Ser. B: Biol. Sci. 271, 227–231, https://doi.org/10.1098/rspb.2003.2570 (2004).
Allen, J. K., Peterson, M. L., Sharrard, G. V., Wright, D. L. & Todd, S. K. Radiated noise from commercial ships in the Gulf of Maine: Implications for whale/vessel collisions. J. Acoust. Soc. Am. 132, EL229–35, https://doi.org/10.1121/1.4739251 (2012).
McKenna, M., Calambokidis, J., Oleson, E., Laist, D. & Goldbogen, J. Simultaneous tracking of blue whales and large ships demonstrates limited behavioral responses for avoiding collision. Endangered Species Res. 27, 219–232. https://doi.org/10.3354/esr00666 (2015).
Argüelles, M. B., Coscarella, M., Fiorito, C. & Bertellotti, M. Southern right whales generally appear not to react to transiting research vessels. Mar. Mammal Sci. 38, 6–17. https://doi.org/10.1111/mms.12843 (2022).
Martin, M. J. et al. Exposure and behavioural responses of tagged bowhead whales (Balaena mysticetus) to vessels in the Pacific Arctic. Arctic Science https://doi.org/10.1139/as-2022-0052 (2023).
Crum, N., Gowan, T., Krzystan, A. & Martin, J. Quantifying risk of whale-vessel collisions across space, time, and management policies. Ecosphere 10, e02713. https://doi.org/10.1002/ecs2.2713 (2019).
Udell, B. J. et al. Integrating encounter theory with decision analysis to evaluate collision risk and determine optimal protection zones for wildlife. J. Appl. Ecol. 56, 1050–1062. https://doi.org/10.1111/1365-2664.13290 (2019).
Redfern, J. V., Becker, E. A. & Moore, T. J. Effects of variability in ship traffic and whale distributions on the risk of ships striking whales. Front. Mar. Sci. 6, https://doi.org/10.3389/fmars.2019.00793 (2020).
Roberts, J. J. et al. Habitat-based cetacean density models for the US Atlantic and Gulf of Mexico. Sci. Rep. 6, 22615. https://doi.org/10.1038/srep22615 (2016).
Waggitt, J. J. et al. Distribution maps of cetacean and seabird populations in the North–East Atlantic. J. Appl. Ecol. 57, 253–269. https://doi.org/10.1111/1365-2664.13525 (2020).
Virgili, A. et al. Seasonal distribution of cetaceans in the European Atlantic and Mediterranean waters. Front. Mar. Sci. 11, 1319791. https://doi.org/10.3389/fmars.2024.1319791 (2024).
Pike, D. G. et al. Estimates of the abundance of cetaceans in the Central North Atlantic from the T-NASS Icelandic and Faroese ship surveys conducted in 2007. NAMMCO Sci. Publ. 11, https://doi.org/10.7557/3.5269 (2019).
Gende, S. M. et al. Active whale avoidance by large ships: Components and constraints of a complementary approach to reducing ship strike risk. Front. Mar. Sci. 6, https://doi.org/10.3389/fmars.2019.00592 (2019).
Sèbe, M., Kontovas, C. A. & Pendleton, L. Reducing whale-ship collisions by better estimating damages to ships. Sci. Total. Environ. 713, 136643. https://doi.org/10.1016/j.scitotenv.2020.136643 (2020).
Sèbe, M., Kontovas, C. A., Pendleton, L. & Gourguet, S. Cost-effectiveness of measures to reduce ship strikes: A case study on protecting the Mediterranean fin whale. Sci. Total. Environ. 827, 154236. https://doi.org/10.1016/j.scitotenv.2022.154236 (2022).
Cook, D., Malinauskaite, L., Davísdóttir, B., Ögmundardóttir, H. & Roman, J. Reflections on the ecosystem services of whales and valuing their contribution to human well-being. Ocean. & Coast. Manag. 186, 105100, https://doi.org/10.1016/j.ocecoaman.2020.105100 (2020).
Sheehy, J. M. et al. Review of evaluation and valuation methods for cetacean regulation and maintenance ecosystem services with the Joint Cetacean Protocol data. Front. Mar. Sci. 9, https://doi.org/10.3389/fmars.2022.872679 (2022).
Cates, K. et al. Strategic plan to mitigate the impacts of ship strikes on cetacean populations: 2017–2020 (International Whaling Commission, In IWC Strategic Plan to Mitigate Ship Strikes (Jersey, 2017).
Domene, X., Ramírez, W., Mattana, S., Alcañiz, J. M. & Andrés, P. Ecological risk assessment of organic waste amendments using the species sensitivity distribution from a soil organisms test battery. Environ. Pollut. 155, 227–236. https://doi.org/10.1016/j.envpol.2007.12.001 (2008).
Koopman, B. O. The theory of search I. Kinematic bases. Oper. research 4, 324–346 (1956).
Glennie, R., Buckland, S. T. & Thomas, L. The effect of animal movement on line transect estimates of abundance. PloS one 10, e0121333. https://doi.org/10.1371/journal.pone.0121333 (2015).
Elith, J. & Leathwick, J. R. Species distribution models: Ecological explanation and prediction across space and time. Annu. Rev. Ecol. Evol. Syst. 40, 677–697. https://doi.org/10.1146/annurev.ecolsys.110308.120159 (2009).
Roberts, J., Yack, T. & Halpin, P. Marine mammal density models for the U.S. navy Atlantic Fleet Training and Testing (AFTT) study area for the phase iv Navy Marine Species Density Database (NMSDD). document version 1.3. Tech. Rep., Report prepared for Naval Facilities Engineering Systems Command, Atlantic by the Duke University Marine Geospatial Ecology Lab, Durham, North Carolina (2023).
Barlow, J., Griffiths, E. T., Klinck, H. & Harris, D. V. Diving behavior of Cuvier’s beaked whales inferred from three-dimensional acoustic localization and tracking using a nested array of drifting hydrophone recorders. J. Acoust. Soc. Am. 144, 2030–2041. https://doi.org/10.1121/1.5055216 (2018).
Würsig, B., Thewissen, J. & Kovacs, K. M. (eds.) Encyclopedia of Marine Mammals (Third Edition) (Elsevier, 2018), academic press edn.
Laran, S. et al. A comprehensive survey of pelagic megafauna: their distribution, densities, and taxonomic richness in the tropical Southwest Indian Ocean. Front. Mar. Sci. 4, 139. https://doi.org/10.3389/fmars.2017.00139 (2017).
Heide-Jørgensen, M. et al. Satellite tracking of minke whales (Balaenoptera acutorostrata) off the coast of northern Norway. J. Cetacean Res. Manage. 3, 175–178 https://doi.org/10.47536/jcrm.v3i2.887 (2001).
Friedlaender, A. et al. Feeding rates and under-ice foraging strategies of the smallest lunge filter feeder, the Antarctic minke whale (Balaenoptera bonaerensis). J. Exp. Biol. 217, 2851–2854. https://doi.org/10.1242/jeb.106682 (2014).
Hain, J. H., Hampp, J. D., McKenney, S. A., Albert, J. A. & Kenney, R. D. Swim speed, behavior, and movement of North Atlantic right whales (Eubalaena glacialis) in coastal waters of northeastern Florida, USA. PloS one 8, e54340. https://doi.org/10.1371/journal.pone.0054340 (2013).
Baird, R. W., Borsani, J. F., Hanson, M. B. & Tyack, P. L. Diving and night-time behavior of long-finned pilot whales in the Ligurian Sea. Mar. Ecol. Prog. Ser. 237, 301–305. https://doi.org/10.3354/meps237301 (2002).
Irvine, L., Palacios, D. M., Urbán, J. & Mate, B. Sperm whale dive behavior characteristics derived from intermediate-duration archival tag data. Ecol. Evol. 7, 7822–7837. https://doi.org/10.1002/ece3.3322 (2017).
Acknowledgements
We are grateful to the many observers who participated in the surveys and collected all the data used to model cetacean densities, as well as to ship captains, crews, and pilots. We thank the Direction Générale de l’Armement Techniques Navales for providing cetacean densities in the Northeast Atlantic Ocean and the Mediterranean Sea. We thank the Duke Marine Geospatial Ecology Laboratory for providing cetacean densities in the Northwest Atlantic Ocean through their web portal (https://seamap.env.duke.edu/models/Duke/EC/). We thank the North Atlantic Marine Mammal Commission (NAMMCO) for providing cetacean densities estimated from the NASS survey.
Funding
The study and open access were funded by Share The Ocean.
Author information
Authors and Affiliations
Contributions
A.V. wrote the main manuscript. A.V., S.F. and M.P. carried out the analyses. V.R., O.L.M. and R.B. contributed their expertise to the study, and R.B. supervised it. All authors reviewed the manuscript.
Corresponding author
Ethics declarations
Competing interests
The authors declare no competing interests.
Additional information
Publisher’s note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
About this article
Cite this article
Virgili, A., Fournier, S., Le Maître, O. et al. Assessing cetacean encounter risk in offshore racing. Sci Rep (2025). https://doi.org/10.1038/s41598-025-33896-6
Received:
Accepted:
Published:
DOI: https://doi.org/10.1038/s41598-025-33896-6