Physical Measures of Welfare in Fin (Balaenoptera physalus) and Humpback Whales (Megaptera novangliae) Found in an Anthropized Environment: Validation of a First Animal-Based Indicator in Mysticetes
by
,
Anik Boileau
1,2,*
,
Jonathan Blais
2,
Marie-Françoise Van Bressem
3,4,
Kathleen E. Hunt
5 and 
Jamie Ahloy-Dallaire
1 1
Faculté des Sciences Animales, Université Laval, Québec, QC G1V 0A6, Canada
2
Centre d’Éducation et de Recherche de Sept-Îles, Sept-Îles, QC G4R 2Y8, Canada
3
Cetacean Conservation Medicine Group, Peruvian Centre for Cetacean Research, Museo de Delfines, Lima 20, Peru
4
ProDelphinus, Miraflores, Lima 18, Peru
5
Department of Biology, Smithsonian-Mason School of Conservation, George Mason University, 1500 Remount Rd, Front Royal, VA 22630, USA
*
Author to whom correspondence should be addressed.
Animals 2024, 14(23), 3519; https://doi.org/10.3390/ani14233519
Submission received: 21 September 2024
/
Revised: 23 November 2024
/
Accepted: 3 December 2024
/
Published: 5 December 2024
(This article belongs to the Section Animal Welfare)
Simple Summary
The welfare of free-ranging cetaceans is being impacted around the world due to human activities like commercial fishing and marine traffic. Here, we validate a non-invasive physical indicator of welfare for humpback and fin whales found in the Gulf of St-Lawrence, Canada. Multi-scale measurement of welfare showed that most humpback whales were in a good welfare state, whereas most fin whales were in a moderate state. For both species, welfare was mainly affected by prolonged effects of physical trauma (entanglement in fishing gear and boat collisions) on body condition, specifically whales being thinner. Other factors impacting welfare included degradation of the marine environment (e.g., oxygen levels, water temperatures and salinity levels).
Abstract
Anthropogenic activities impacting marine environments are internationally recognized as welfare issues for wild cetaceans. This study validates a first evidence-based physical indicator for the welfare assessment protocol of humpback (n = 50) and fin whales (n = 50) living in a highly anthropized environment. Visual assessments of body condition, skin health, prevalence of injuries and parasite/epibiont loads were performed using a species-specific multi-scale measuring tool. A total of 6403 images were analyzed (fin, n = 3152; humpback, n = 3251) and results were validated through reliability and positive discrimination statistical tests. Based on physical measures, welfare assessment results showed that 60% of humpback whales were considered in a good welfare state compared to only 46% of fin whales. Significant relationships were observed in both species, between environmental parameters like dissolved oxygen levels, and prevalence of cutaneous lesions like pale skin patch syndrome. Furthermore, animals with injuries due to anthropogenic activities were more likely to be in poorer body condition, suggesting chronic stress affecting welfare.
