Sound the seashell trumpets! As reported by the Seattle Times (in a great article worth checking out), Harbor Porpoises are once again populating the Puget Sound in numbers after a decades-long absence. Last common in the 40’s and 50’s, possible reasons for their disappearance include industrial pollution, vessel noise, and entanglement in gill nets, which researchers say might have driven the porpoises further north. But it now appears that these troublesome conditions have reduced enough for them to return, and they’ve become a common sight once again. This is something of an environmental victory for the city, giving cause to deem Seattle’s pollution cleanup efforts effective.
The order Catacea refers to Porpoises, Dolphins, and Whales, and these Harbor Porpoises are now the only Catacean in the Puget Sound existing solely in inland marine waters. Averaging around 5 ft. and 120 pounds, Harbor Porpoises are shy creatures who usually travel alone or in a small group of 2-5. They dive as deep as 656 ft., but usually stay near the surface. Clearly this is due to their affection towards humans as well as their frequent breathing intervals. I mean, just look at that friendly mug.
Harbor Porpoises live an average of twenty years, going about their business quietly, sans flashy behavior such as splashing or rolling in the water. They are one of many animals who use echolocation, a biological sonar that calls out to the environment and listens for the echoes that find their way back from nearby objects. You can tell them apart from dolphins by their distinctively short beaks. They’re a highly reproductive species, females often giving birth every year for several years in a row.
Though their reemergence is a positive sign, concern is growing regarding the amount of Harbor Porpoises being seen, dead or alive, stranded on dry land (these sightings are called “strandings”). This could be due to a population increase only, but could also be a sign of a deeper problem within their living situation. The mammals have been listed as a vulnerable species by the World Conservation Union, and are just another reason for us to make little efforts within our urban environment to keep Seattle a place where concrete and nature can coexist as peacefully as possible.