February 28, 2018

Dall’s Porpoise Expands Territory in a Changing Prince William Sound

A Dall's Porpoise swims in Prince William Sound.

Dall’s porpoise are not hard to find in Alaska waters. If you are in a boat, chances are they will find you. Possibly the fastest of all dolphins and porpoises, Dall’s are notorious bow riders, darting back and forth in front of a moving ship, carving a rooster-tail spray as they surf the bow wave.

This affinity for ships and speed makes the compact black-and-white porpoise one of Alaska’s more visible marine mammals, but also one of the most difficult to study. Their behavior confounds traditional survey methods that depend on research subjects not racing eagerly toward the survey vessel. Although Dall’s porpoise are an abundant fish predator, they have been little studied in Prince William Sound since the 1980s – before the Exxon Valdez oil spill.

NOAA Fisheries scientists, under the Gulf Watch Alaska monitoring program, have now analyzed Dall’s porpoise distribution in Prince William Sound for the first time in nearly three decades. They found some behaviors contrary to what scientists knew about Dall’s, signaling major changes in the Prince William Sound ecosystem.

Read the full NOAA Fisheries Highlights article to learn more: https://www.fisheries.noaa.gov/feature-story/dalls-porpoise-expands-territory-changing-prince-william-sound