Estimated summer abundance and krill consumption of fin whales throughout the Scotia Sea during the 2018/2019 summer season

Estimated summer abundance and krill consumption of fin whales throughout the Scotia Sea during the 2018/2019 summer season | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Estimated summer abundance and krill consumption of fin whales throughout the Scotia Sea during the 2018/2019 summer season Martin Biuw, Ulf Lindstrøm, Jennifer A. Jackson, Mick Baines, and 4 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-3959755/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Among large cetaceans in the Southern Hemisphere, fin whales were the most heavily exploited in terms of numbers taken during the period of intense industrial whaling. Recent studies suggest that, whilst some humpback whale populations in the Southern Hemisphere appears to have almost completely recovered to their estimated pre-whaling abundance, much less is known about the status of Southern Hemisphere fin whales. Circumpolar estimates in the 1990s suggest an abundance of about 5 500 animals south of 60° S, while the IDCR/SOWER-2000 survey for the Scotia Sea and Antarctic Peninsula areas estimated 4,670 fin whales within this region in 2000. More recent studies in smaller regions indicate higher densities, suggesting that previous estimates are overly conservative and/or that fin whales are undergoing a substantial increase. Here we report findings from a recent multi-vessel single-platform sightings survey carried out as part of the 2019 Area 48 Survey for Antarctic krill. While fin whales were encountered throughout the entire survey area, which covered the majority of CCAMLR Management Area 48, they were particularly abundant around the South Orkney Islands and the eastern Bransfield Strait. Large feeding aggregations were also encountered within the central Scotia Sea between South Orkney Islands and South Georgia. Distance sampling analyses suggest an average fin whale density throughout the Scotia Sea of 0.0256 (CV=0.149) whales per km 2 , which agrees well with recent density estimates reported from smaller sub-regions within the Scotia Sea. Design-based distance sampling analyses resulted in an estimated total fin whale abundance of 53,873 (CV=0.15, 95% CI: 40,233 - 72,138), while a density surface model resulted in a slightly lower estimate of 50,837 (CV: 0.136, 95% CI: 38,966 - 66,324). These estimates are at least an order of magnitude greater than the previous estimate from the same region based on the IDCR/SOWER-2000 data, suggesting that fin whales are undergoing a substantial abundance increase in the South Atlantic. This may have important implications for the assessment of cetacean population trends, but also for CCAMLRs spatial overlap analysis process and efforts to implement a Feedback Management system for Antarctic krill. Our abundance estimate suggests an annual summer krill consumption by fin whales in the Antarctic Peninsula and Scotia Sea area of 7.97 (95% CI: 4.94 - 11.91) million tonnes, which would represent around 20 times the total krill catch taken by the commercial fishery in Area 48 in the same season, or about 12.7% of the 2019 summer krill standing stock estimated from data collected during the same survey. This highlights the crucial importance of including cetacean krill predators in assessment and management efforts for living marine resources in the Southern Ocean, and particularly stresses the urgent need for a re-appraisal of abundance, distribution and ecological role of Southern Hemisphere fin whales. Marine and Freshwater Ecology Population Biology Fin whales abundance Southern Ocean Distance sampling Scotia Sea Full Text Additional Declarations The authors declare no competing interests. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-3959755","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":273102696,"identity":"228f69b0-53cc-436f-9d68-52a05e87dbb0","order_by":0,"name":"Martin Biuw","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAsUlEQVRIiWNgGAWjYLCCBCBiY2BgfMxgQJwGxgaoFmZj4rVALGJgkyZKvW772ecPHu5gyOOTyDGrLihgyOMnpMXsTLphQ+IZhmI2oJbbMwwYiiUbCGk5kMbYkNjGkNgmkbvtNo8BQ+KGA4S0nH+G0FJMnJYbSLYwE6nlGeMMoPpiNp73n6V5DCQSZxL0y/k0ho8/22zy5NvTEj/z/LFJ7CegAwYkMBijYBSMglEwCigBAE4GO5jm5uXMAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0001-8051-3399","institution":"Norwegian Institute of Marine Research","correspondingAuthor":true,"prefix":"","firstName":"Martin","middleName":"","lastName":"Biuw","suffix":""},{"id":273107851,"identity":"c3900b76-144d-4da2-83f1-f1650be60068","order_by":1,"name":"Ulf Lindstrøm","email":"","orcid":"","institution":"Norwegian Institute of Marine Research","correspondingAuthor":false,"prefix":"","firstName":"Ulf","middleName":"","lastName":"Lindstrøm","suffix":""},{"id":273107852,"identity":"b1253eb2-642f-49d5-b035-cda8af858667","order_by":2,"name":"Jennifer A. 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While fin whales were encountered throughout the entire survey area, which covered the majority of CCAMLR Management Area 48, they were particularly abundant around the South Orkney Islands and the eastern Bransfield Strait. Large feeding \u0026nbsp;aggregations were also encountered within the central Scotia Sea between South Orkney Islands and South Georgia. Distance sampling analyses suggest an average fin whale density throughout the Scotia Sea of 0.0256 (CV=0.149) whales per km\u003csup\u003e2\u003c/sup\u003e, which agrees well with recent density estimates reported from smaller sub-regions within the Scotia Sea. Design-based distance sampling analyses resulted in an estimated total fin whale abundance of 53,873 (CV=0.15, 95% CI: 40,233 - 72,138), while a density surface model resulted in a slightly lower estimate of 50,837 (CV: 0.136, 95% CI: 38,966 - 66,324). 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