Killer whales (Orcinus orca) feeding on lumpfish (Cyclopterus lumpus) in northern Norway

• Published in: Marine Mammal Science
• Main Authors: Jourdain, Eve, Karoliussen, Richard, Vos, Jacques, Zakharov, Stanislav, Tougard, Christelle
• Other Authors: Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement IRD : UR226-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2020
• Subjects: seasonality; site-fidelity; Orcinus orca; killer whale; feeding behavior; foraging; foraging strategy; [SDV.EE.IEO]Life Sciences [q-bio]/Ecology; environment/Symbiosis; [SDV.BA.ZV]Life Sciences [q-bio]/Animal biology/Vertebrate Zoology; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; Killer Whale; Northern Norway; Orca; Killer whale
• Online Access: https://hal.science/hal-02162319; https://hal.science/hal-02162319/document; https://hal.science/hal-02162319/file/Jourdain_MarMamSc.pdf; https://doi.org/10.1111/mms.12618

International audience Killer whales (Orcinus orca) in Norwegian waters have long been known to rely on Atlantic herring (Clupea harengus) as a main prey resource. However, research almost exclusively conducted at seasonal herring grounds may have biased studies away from detecting other potentially significant prey species. Since 2013, dedicated research efforts have focused on monitoring killer whale occurrence and foraging ecology throughout the year in northern Norway. This study presents results on site‐fidelity of photographically identified individuals, predation records and behavioral patterns from five spring seasons (March–April) in 2014–2018 in Andfjord, northern Norway. A minimum number of 75 adult and subadult killer whales (out of a catalog of 971 individuals) returned seasonally to the study area for foraging and residency for up to six weeks. Lumpfish (or lumpsucker, Cyclopterus lumpus) was the only type of prey identified (based on molecular or visual identification) on 22 predation events from 2016 (n = 4), 2017 (n = 2) and 2018 (n = 16). Spatial group cohesion observed when foraging was a potential adaptation for efficiently hunting this prey species. These whales were also encountered at herring wintering grounds the same years, but with different group sizes. Such behavioral adaptations suggested intraannual switching between prey resources and foraging strategies.