Salmon Shark (Lamna ditropis) scratching behaviour using floating anthropogenic debris
Keywords:scratching, salmon shark, animal behaviour, changing ocean, parasites, traditional ecological knowledge, drone, shark, Lamna ditropis, marine pollution
Observations of animal behaviour in the open ocean are relatively rare. However, while conducting surveys in the Northeast Pacific in the summers of 2019 and 2021, we encountered two Salmon Shark (Lamna ditropis) using floating anthropogenic debris to scratch their bodies. We captured the activity with aerial (drone) and underwater cameras. We document and describe this novel behaviour as high energy, high impact, repetitive, fast, and long lasting (e.g., every ~15 s for >20 minutes). We explore these observations in light of traditional ecological knowledge and scientific literature.
Copyright for Canadian Field-Naturalist content is held by the Ottawa Field-Naturalists' Club, except for content published by employees of federal government departments, in which case the copyright is held by the Crown. In-copyright content available at the Biodiversity Heritage Library is available for re-use under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 (CC BY-NC-SA 4.0) licence. For usage of content at the BHL for purposes other than those allowed under this licence, contact us.
To request use of copyright material, please contact our editor, Dr. Dwayne Lepitzki: editor -at- canadianfieldnaturalist -dot- ca