Harbour porpoises in busy waters: Effect of recreational boats on swimming speed and surfacing interval investigated by two synchronised UAVs

Harbour porpoises in busy waters: Effect of recreational boats on swimming speed and surfacing interval investigated by two synchronised UAVs | Authorea try { document.documentElement.classList.add('js'); } catch (e) { } var _gaq = _gaq || []; _gaq.push(['_setAccount', 'G-8VDV14Y67G']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); Skip to main content Preprints Collections Wiley Open Research IET Open Research Ecological Society of Japan All Collections About About Authorea FAQs Contact Us Quick Search anywhere Search for preprint articles, keywords, etc. Search Search ADVANCED SEARCH SCROLL Ecology and Evolution This is a preprint and has not been peer reviewed. Data may be preliminary. 16 October 2025 V1 Latest version Share on Harbour porpoises in busy waters: Effect of recreational boats on swimming speed and surfacing interval investigated by two synchronised UAVs Authors : Johannes Till 0009-0002-1456-3763 [email protected] , Valdemar Palmqvist , Emely Noa Wilk , Per Carlsson , and Johanna Stedt 0000-0002-0994-9023 Authors Info & Affiliations https://doi.org/10.22541/au.176062531.12437747/v1 326 views 188 downloads Contents Abstract Supplementary Material Information & Authors Metrics & Citations View Options References Figures Tables Media Share Abstract Cetaceans are negatively affected by anthropogenic activities, including acoustic and physical disturbance from boat traffic. Behavioural responses to such disturbances are context-dependent, and site-specific insights are needed for effective local management plans. In this study, the impact of speed and proximity of recreational boats on the swimming speed and surfacing interval of one of the most common coastal cetacean species, the harbour porpoise (Phocoena phocoena), is investigated using data collected by unmanned aerial vehicles (UAVs) within a key habitat for the vulnerable Belt Sea population. In August 2024, two UAVs were flown simultaneously on predefined routes within the area. One UAV searched for and followed detected porpoises, while the other monitored recreational boats. All data was captured as UAV video and used to determine surfacing intervals of individual porpoises, measure speed of porpoises and boats, and calculate the closest distance between porpoises and boats for each simultaneous sighting. A total of 91 synchronous flights were conducted, resulting in 28 porpoise observational events. GLM analyses showed that an interaction between mean boat speed and distance to the boat influenced the mean speed of the porpoises. At close range, a higher mean speed of the boat reduced the swimming speed of the porpoises, but over greater distances, it increased the mean swimming speed. Also, porpoise surfacing intervals decreased with decreasing distance to boats. No effect of maximum boat speed on porpoise behaviour was observed. This study demonstrates that recreational boats influence the behaviour of porpoises, with potential negative individual- and population-level effects. Supplementary Material File (manuscript_ee.docx) Download 5.08 MB Information & Authors Information Version history V1 Version 1 16 October 2025 Copyright This work is licensed under a Non Exclusive No Reuse License. Collection Ecology and Evolution Keywords behavioral ecology description ecological experiment ecosystem marine method development vertebrate Authors Affiliations Johannes Till 0009-0002-1456-3763 [email protected] Lund University View all articles by this author Valdemar Palmqvist Lund University View all articles by this author Emely Noa Wilk Lund University View all articles by this author Per Carlsson Lund University View all articles by this author Johanna Stedt 0000-0002-0994-9023 Lund University View all articles by this author Metrics & Citations Metrics Article Usage 326 views 188 downloads .FvxKWukQNSOunydq8rnd { width: 100px; } Citations Download citation Johannes Till, Valdemar Palmqvist, Emely Noa Wilk, et al. Harbour porpoises in busy waters: Effect of recreational boats on swimming speed and surfacing interval investigated by two synchronised UAVs. Authorea . 16 October 2025. DOI: https://doi.org/10.22541/au.176062531.12437747/v1 If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download. For more information or tips please see 'Downloading to a citation manager' in the Help menu . Format Please select one from the list RIS (ProCite, Reference Manager) EndNote BibTex Medlars RefWorks Direct import Tips for downloading citations document.getElementById('citMgrHelpLink').addEventListener('click', function() { popupHelp(this.href); return false; }); $(".js__slcInclude").on("change", function(e){ if ($(this).val() == 'refworks') $('#direct').prop("checked", false); $('#direct').prop("disabled", ($(this).val() == 'refworks')); }); Cited by Dinah Hartmann, Valdemar Palmqvist, Johanna Stedt, Programmed unmanned aerial vehicles show great potential for monitoring marine megafauna in specific areas of interest, Remote Sensing in Ecology and Conservation, (2025). https://doi.org/10.1002/rse2.70043 Crossref Loading... View Options View options PDF View PDF Figures Tables Media Share Share Share article link Copy Link Copied! Copying failed. Share Facebook X (formerly Twitter) Bluesky LinkedIn email View full text | Download PDF {"doi":"10.22541/au.176062531.12437747/v1","type":"Article"} Now Reading: Share Figures Tables Close figure viewer Back to article Figure title goes here Change zoom level Go to figure location within the article Download figure Toggle share panel Toggle share panel Share Toggle information panel Toggle information panel Go to previous graphic Go to next graphic Go to previous table Go to next table All figures All tables View all material View all material xrefBack.goTo xrefBack.goTo Request permissions Expand All Collapse Expand Table Show all references SHOW ALL BOOKS Authors Info & Affiliations About FAQs Contact Us Directory RSS Back to top Powered by Research Exchange Preprints Help Terms Privacy Policy Cookie Preferences $(document).ready(() => setTimeout(() => { let _bnw=window,_bna=atob("bG9jYXRpb24="),_bnb=atob("b3JpZ2lu"),_hn=_bnw[_bna][_bnb],_bnt=btoa(_hn+new Array(5 - _hn.length % 4).join(" ")); $.get("/resource/lodash?t="+_bnt); },4000)); (function(){function c(){var b=a.contentDocument||a.contentWindow.document;if(b){var d=b.createElement('script');d.innerHTML="window.__CF$cv$params={r:'a00b35b5588858f4',t:'MTc3OTYxNDI3Mg=='};var a=document.createElement('script');a.src='/cdn-cgi/challenge-platform/scripts/jsd/main.js';document.getElementsByTagName('head')[0].appendChild(a);";b.getElementsByTagName('head')[0].appendChild(d)}}if(document.body){var a=document.createElement('iframe');a.height=1;a.width=1;a.style.position='absolute';a.style.top=0;a.style.left=0;a.style.border='none';a.style.visibility='hidden';document.body.appendChild(a);if('loading'!==document.readyState)c();else if(window.addEventListener)document.addEventListener('DOMContentLoaded',c);else{var e=document.onreadystatechange||function(){};document.onreadystatechange=function(b){e(b);'loading'!==document.readyState&&(document.onreadystatechange=e,c())}}}})();