How to catch a sea monster: acoustic telemetry and stable isotope analysis of Atlantic wolffish (Anarhichas lupus)

Abstract

Atlantic wolffish (Anarhichas lupus) became Canada's first fully marine at-risk species under the Species at Risk Act (SARA) following an 87% population decline from the late 1970s to the mid-1990s, including a 60% decrease in mature individuals. Populations on the Scotian Shelf have fallen by 65% since 1980 and continue to decline. Limited knowledge of wolffish biology hindered the identification of critical habitats under the current recovery management plan. To address this, I employed acoustic telemetry to track continuous movement, scuba surveys to observe in-situ behaviours and stable isotope analysis for trophic position estimation. I uncovered seasonal migrations linked to spawning and foraging, pair bonding, tooth replacement, den usage patterns, and egg-guarding. Trophic position assessment yielded a 3.7 value, supporting their role as keystone predators. This investigation designated Deer Island Point as a critical habitat for Atlantic wolffish and offered insight into their ecological significance in the Bay of Fundy.