Sperm and northern bottlenose whale interactions with deep-water trawlers in the western North Atlantic

• Published in: PLOS ONE
• Main Authors: Oyarbide, Usua, Feyrer, Laura Joan, Gordon, Jonathan
• Other Authors: Riascos, José M., National Geographic Society Education Foundation, Fisheries and Oceans Canada
• Format: Article in Journal/Newspaper
• Language: English
• Published: Public Library of Science (PLoS) 2023
• Subjects: Greenland; hyperoodon ampullatus; North Atlantic; Northern bottlenose whale; Physeter macrocephalus
• Online Access: http://dx.doi.org/10.1371/journal.pone.0289626; https://dx.plos.org/10.1371/journal.pone.0289626

Commercial fisheries have increased in all the world’s oceans with diverse unintended impacts on marine ecosystems. As a result of resource overlap, interactions between cetaceans and fisheries are a common occurrence and, in many cases, can give rise to significant conservation issues. Research on the distribution and types of such interactions is important for efficient management. In this study, we describe the behaviors of two whale species: sperm whales ( Physeter macrocephalus ) and northern bottlenose whales ( Hyperoodon ampullatus ), interacting with benthic trawlers fishing off the eastern Grand Banks of the western North Atlantic in 2007. Whale interactions were only observed when vessels were targeting Greenland halibut ( Reinhardtius hippoglossoides ) in deep-water fishing areas and were most common during net hauling. Sperm whales and northern bottlenose whales appeared to engage in feeding behavior close to the surface during hauling, especially during the latter stages, suggesting they targeted fish escapees rather than discards. Using photo-identification methods, seven individual sperm whales were identified with multiple resights of six individuals being recorded over an almost two month period. The maximum distance between two resights was 234 km, suggesting individual sperm whales were repeatedly targeting and even following fishing vessels over multiple days and between fishing areas. By contrast, there were no photographic resights of individual northern bottlenose whales within this study, or with substantial photo-identification catalogues from other adjacent high density areas, suggesting that individuals of this species may be less likely to follow vessels or move between areas. This study documents the earliest confirmed records of northern bottlenose whales in this remote region. These interactions and high encounter rates may indicate that adjacent populations are recovering from the previous century of commercial whaling. Our study provides new insights and details on ...