Southeast Alaska Sperm Whale Avoidance Project (SEASWAP)
By actively participating in the latest research, Fishery Conservation Network fishermen work to protect marine mammal populations while maintaining viable coastal fisheries. Since 2008, they have collaborated with scientists from the University of Alaska, Sitka Sound Science Center, and Scripps Oceanographic Institute to collect genetic and behavioral data on sperm whales that are predators of longline-caught sablefish.
Working with the scientists, FCN fishermen recorded acoustic data from sperm whales preying on longline hooked fish to assess the amount of depredation. Quantifying depredation strengthens the fishery assessment process and ensures catch limits accurately reflect abundance. New fishing gear and techniques were also developed and tested by fishermen to improve species selectivity and reduce interactions with marine mammals.
The initial collaboration yielded some key information about Alaska's sperm whales:
- They are almost all immature whales.
- Repeat offenders are generally responsible for predation.
- The sound of engines cycling act as dinner bells for whales.
Building on this new knowledge, the collaborators, known as the SEASWAP Team, designed deterrents that were field tested in the summer of 2012. Tested deterrents included decoy buoys with playback devices, as well as bead ear designed to acoustically confuse whales targeting hooked sablefish. Additionally, recorders were deployed with each deterrent to acoustically record the response of each whale.
Although the whales ignored playback sounds of killer whales, white noise and static, whales were lured and retained for over two hours at a decoy buoy with a playback device broadcasting an underwater recording of a boat engaging hydraulics and shifting in and out of gear. While the whales waited by the decoy buoy, a longline boat hauled a nearby string of blackcod gear. Whales are intelligent creatures, however, and some individuals soon learned how to spot a decoy and search out the active gear instead. In 2013, the SEASWAP Team met with fishermen from Australia and New Zealand (who also have whale depredation problems) to exchange information and new designs for whale deterrent gear.
In 2010, the Central Bering Sea Fishermen's Association (CBSFA) joined the research team with both financial and logistical support for the sperm whale deterrent work and an expansion of the killer whale research. As most fishermen know, killer whales remove catch from longline gear with great efficiency in western Alaska fishing areas. CBSFA boats deployed hydro-acoustic recorders to learn about killer whale predation behavior, and they will test decoy buoys with playback devices in the future.
If you have sablefish to catch and want to try out the deterrent gear, please call the Alaska Longline Fishermen's Association at (907) 747-3400 or email.