Moby Dick and Captain Ahab Reinvented: Effects of Cetacean Depredation on Alaskan Longline Fishermen

Apex predators such as killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus) directly compete with humans for living marine resources. One example of this competition is whale depredation on longline fisheries in Alaska. Sperm whale and killer whale depredation occurs when whales remove fish from longline gear, and damage fish or fishing gear. Depredation events by killer whales and sperm whales are increasing globally in frequency, geographic extent, and severity. Whale depredation can reduce overall catch rates by up to 30% and individual sets catch rates by 100%. These interactions have negative consequences for both the fishermen and the whales. The goal of this project is to use semi-directed interviews with longline fishermen to determine how cetacean depredation is shaping fishing practices, sustainability and fishery management in Alaska. Initial interview results suggest fishermen are often forced to change fishing areas, change gear types, extend set soak times and travel greater distances to avoid depredating whales. Changes in fishing behavior associated with depredation often lead to less efficient fishing methods. Results from semi-directed interviews will be used to create a formal questionnaire for distribution in Alaskan longline fishing communities in 2011/2012. Findings and qualitative insights from this study will also support more quantitative depredation analyses. A better understanding of depredation in Alaska from the fishermen’s perspective will be important in determining feasible management options in the future. This research is necessary to effectively address the needs of fishermen while sustainably managing marine mammal and fish stocks.