The Southeast Alaska Sperm Whale Avoidance Project (SEASWAP) was initiated in 2003 by fishermen concerned by the increasing presence of sperm whales around longline boats. At first the whales just ate the fish guts and heads being returned to the sea as fish were cleaned, but soon the whales were helping themselves to the sablefish caught on longline hooks.

Depredation is estimated to cause thousands of dollars of losses to fishermen each year, and may also be affecting accurate reporting of the sablefish resource. It also poses a safety risk to both fishermen and whales, since whales run the risk of becoming entangled in gear as it is hauled aboard and fishermen run the risk of being injured by whales tangled in fishing gear. Although serious injury has been avoided to date, fishermen joined with biologists and bioacoustics scientists to study sperm whale behavior and explore avoidance strategies. This unique collaboration became known as SEASWAP.

A sperm whale grabs the longline in an attempt to remove sablefish (black cod) as longline gear is pulled aboard the F/V Cobra in the Gulf of Alaska.

Research and Findings

Over the years, the SEASWAP team has collected whale genetic and behavioral data, and worked with fishermen to identify and test deterrents.

The SEASWAP team has identified 130 whales in Southeast Alaska and learned that most, if not all, are immature males. Of these 130, twelve to fifteen whales are serious offenders—or serial depredators, as the SEASWAP team calls them. 

Scientists have also discovered that the sound of a fishing boat’s engine shifting in and out of gear is a dinner bell for the whales, letting them know a longliner is hauling gear and fish will soon be served.

Investigators have tested a series of deterrents, satellite tagged sperm whales to study their movements, and (in 2014) pilot tested a sperm whale avoidance network. You can learn about this work and more on the SEASWAP project website.  

Curious about whale depredation in other parts of the world? Check out this publication about False Killer Whale depredation of longline gear in Hawaii, released in November 2016. 

Get Involved


ALFA tested a newly improved hydrophone array in Spring 2019. This new hydrophone allowed us to pinpoint the location of sperm whales with 8 miles of the deployment. Several vessels carried the equipment throughout the fishing grounds during the fishing season, and sperm whale location data was sent via satellite to Sitka, after which ALFA relayed sperm whale activity areas to fishermen via inReach® text. Sign up with ALFA and call the ALFA office (907-747-3400) to join SEASWAP’s real-time sperm whale avoidance network. 

Network members are using satellite phones or inReach® equipment supplied by ALFA to share reports of whale location and activity. This up to date information helps fishermen avoid the whales and minimize depredation.  Fishermen’s watchfulness is integral to the avoidance project, and the more eyes we have watching for whales the better. By actively participating in this research, fishermen are working together to protect whales, the sablefish resource, and coastal economies.

If you see sperm whales, you can call or text the SEASWAP team at 907-738-4494 or Linda Behnken at 907-738-3615.  Our goal is to help you avoid whales and efficiently harvest your fish. 

Tips for Avoiding Whales

  1. Never hang around deployed gear. Head directly to your planned fishing area, drop your gear as fast as possible, then move 5-6 miles away, preferably toward the coast into shallow water. (Sperm whales generally do not travel in shallow water, and in addition shallow water (200 fathom or less) reduces the distance that sound from boats travel.)  Also, HAUL GEAR QUICKLY. When approaching, do not change your engine rpm or course if possible. Go directly to the gear and work quickly. Statistics show that if whales are not near the gear when hauling begins, they will not show up for an hour or two.

  2. Try to “fake out” the whales. If whales arrive mid-deployment, slowly (5 knots or less) move the vessel three or so miles away from the set. Engage and disengage your engine several times, and make a decoy set. Drift in the decoy area overnight, drop additional buoys, make engine noise. When it is time to haul the real set, head inland (keep in mind shallow water muffles noise), travel parallel to the coast for 2-3 miles, and then head to your true set. This will buy you a bit of time, and lessen the predictability of hauls, hopefully further confusing whales.

  3. Deploy or haul while another vessel is in the area. Team up with other vessels. When two vessels are in the same area (but 5 miles apart), one can distract whales while waiting to haul, while the other makes a successful set/haul.

  4. Buy a hydrophone. Hydrophone equipment runs around $300, and is a good way to provide yourself with a heads-up that whales are in the area, allowing you to make decisions on your set and the area.

  5. Minimize shifting in and out of gear. With a calm ocean and confirmed whales in the area, try to minimize how many times the vessel is shifted in and out of gear. The cavitation noise when a propeller is first engaged has been shown to attract whales. Try a circle haul to avoid engaging the engine.

  6. Modified gear. Underwater camera shows animals hesitating to approach line sections that have unusual items attached to it. Animals often run the line across their jaw, and items such as flashers restrict this ability.

  7. Use active deterrent devices. Although animals adapt quickly to most sounds, the addition of unfamiliar noises seems to deter animal exploration.