Abstract
ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 32:351-361 (2017) - DOI: https://doi.org/10.3354/esr00825 Increased proximity of vessels reduces feeding opportunities of blue whales in the St. Lawrence Estuary, Canada Véronique Lesage1,*, Abdelghani Omrane1,2, Thomas Doniol-Valcroze1, Arnaud Mosnier1 1Maurice Lamontagne Institute, Fisheries and Oceans Canada, Mont-Joli, Quebec G5H 3Z4, Canada 2Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, Rimouski, Québec G5L 3A1, Canada *Corresponding author: veronique.lesage@dfo-mpo.gc.ca ABSTRACT: Blue whales Balaenoptera musculus occur seasonally in the St. Lawrence Estuary, Canada, where they spend most of their time foraging. Their recurrent presence has stimulated the development of a large whale-watching industry. Here, we examine the effect of vessel distance on blue whale foraging behaviour by measuring changes in surface and diving patterns. Vessels were within 2000 m of blue whales during 70% of 33 follows, and 59% of total observation time. At vessel distances ≤400 m, surface and dive times were on average 49 and 36% shorter, respectively, and the number of breaths taken by the whales was reduced by 51% compared to control observations without vessel presence within 2000 m of whales. The consequent reduction in foraging time was likely greater than 36%, given that transit time is incompressible and foraging depth is dictated by where krill densities are located. We showed that the relative proportion of lost foraging time from vessel exposure increased exponentially with prey depth. Whales were unable to compensate for lost feeding opportunities by increasing diving rate or swim speed, except when feeding within 10 to 15 m of the surface. Our results indicate that preventing vessels from entering within a 400 m radius around blue whales can help reduce the negative effects of marine recreational activities on blue whale foraging. KEY WORDS: Disturbance · Behaviour · Whale-watching · Foraging · GLMM · GEE Full text in pdf format PreviousNextCite this article as: Lesage V, Omrane A, Doniol-Valcroze T, Mosnier A (2017) Increased proximity of vessels reduces feeding opportunities of blue whales in the St. Lawrence Estuary, Canada. Endang Species Res 32:351-361. https://doi.org/10.3354/esr00825 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 32. Online publication date: May 04, 2017 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2017 Inter-Research.
Highlights
Vessel traffic may alter marine mammal behaviour through their physical presence, elevated underwater noise levels and exposure to collision risks (Richardson et al 1995, Laist et al 2001, Nowacek et al 2007, Clark et al 2009, Parsons 2012, Pirotta et al 2015)
To assess the adequacy of the 400 m limit for mitigating potential effects from whale-watching and other vessel interactions on foraging blue whales, we report on their short-term behavioural responses to vessel proximity, using variables related to breathing and diving patterns
For air-breathing animals living in aquatic environments, an event that reduces time spent at the surface and the number of breaths taken can limit diving capacity, and foraging time
Summary
Vessel traffic may alter marine mammal behaviour through their physical presence, elevated underwater noise levels and exposure to collision risks (Richardson et al 1995, Laist et al 2001, Nowacek et al 2007, Clark et al 2009, Parsons 2012, Pirotta et al 2015). Whale-watching, a form of vessel traffic in which boat operators and tourists seek to interact with marine mammals, is a lucrative business that has developed rapidly and widely over the past decades (O’Connor et al 2009). This type of activity has been repeatedly shown to elicit short-term be-. In cases where foraging represents the predominant activity, metrics related to respiratory patterns and dive time can be reasonable proxies for estimating loss of feeding opportunities associated with vessel interaction and the potential effects on vital rates In cases where foraging represents the predominant activity, metrics related to respiratory patterns and dive time can be reasonable proxies for estimating loss of feeding opportunities associated with vessel interaction and the potential effects on vital rates (e.g. Christiansen & Lusseau 2015)
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