Killer whale (Orcinus orca) interactions with blue-eye trevalla (Hyperoglyphe antarctica) longline fisheries

Paul Tixier; Mary-Anne Lea; Mark A Hindell; Christophe Guinet; Nicolas Gasco; Guy Duhamel; John P Y Arnould

doi:10.7717/peerj.5306

Killer whale (Orcinus orca) interactions with blue-eye trevalla (Hyperoglyphe antarctica) longline fisheries

PeerJ. 2018 Aug 8:6:e5306. doi: 10.7717/peerj.5306. eCollection 2018.

Authors

Paul Tixier¹, Mary-Anne Lea², Mark A Hindell², Christophe Guinet³, Nicolas Gasco⁴, Guy Duhamel⁴, John P Y Arnould¹

Affiliations

¹ School of Life and Environmental Sciences (Burwood Campus), Deakin University, Geelong, Victoria, Australia.
² Ecology and Biodiversity Centre, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia.
³ Centre d'Etudes Biologiques de Chizé (CEBC), UMR 7372 Université de La Rochelle-CNRS, Villiers-en-Bois, France.
⁴ Département Adaptations du vivant, UMR BOREA, Museum national d'Histoire naturelle, Paris, France.

Abstract

Over the past five decades, marine mammal interactions with fisheries have become a major human-wildlife conflict globally. The emergence of longline fishing is concomitant with the development of depredation-type interactions i.e., marine mammals feeding on fish caught on hooks. The killer whale (Orcinus orca) is one of the species most involved in depredation on longline fisheries. The issue was first reported in high latitudes but, with increasing expansion of this fishing method, other fisheries have begun to experience interactions. The present study investigated killer whale interactions with two geographically isolated blue-eye trevalla (Hyperoglyphe antarctica) fisheries operating in temperate waters off Amsterdam/St. Paul Islands (Indian Ocean) and south-eastern Australia. These two fisheries differ in the fishing technique used (vertical vs. demersal longlines), effort, catch, fleet size and fishing area size. Using 7-year (2010-16) long fishing and observation datasets, this study estimated the levels of killer whale interactions and examined the influence of spatio-temporal and operational variables on the probability of vessels to experience interactions. Killer whales interactions occurred during 58.4% and 21.2% of all fishing days, and over 94% and 47.4% of the fishing area for both fisheries, respectively. In south-eastern Australia, the probability of occurrence of killer whale interactions during fishing days varied seasonally with a decrease in spring, increased with the daily fishing effort and decreased with the distance travelled by the vessel between fishing days. In Amsterdam/St. Paul, this probability was only influenced by latitude, with an increase in the southern part of the area. Together, these findings document two previously unreported cases of high killer whale depredation, and provide insights on ways to avoid the issue. The study also emphasizes the need to further examine the local characteristics of fisheries and the ecology of local depredating killer whale populations in as important drivers of depredation.

Keywords: Blue-eye trevalla; Depredation; Fisheries; Fisheries interaction; Hyperoglyphe antarctica; Killer whale; Longline fisheries; Orcinus orca.

Grants and funding

This work was funded by the Australian Research Council (Linkage Project 160100329) and industry partners Australian Longline Pty. Ltd. and Austral Fisheries Pty. Ltd. PECHEKER database was supported by Direction des Pêches Maritimes et de l’Aquaculture (DPMA of Ministère de l’Agriculture et de l’Alimentation). Additional funding was provided by the Syndicat des Armements Réunionais des Palangriers Congélateurs (SARPC), the Fondation des Mers Australes and Agence Nationale pour la Recherche (ANR 17-CE32-0007-01) as part of the «OrcaDepred» project. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.