After an absence of over 65 years, the harbor porpoise recently returned to frolic in the waters of San Francisco Bay. Why did the harbor porpoises return? And why did they originally leave?
According to researcher Bill Keener, several reasons might explain their reoccupation, including the reduction of pollution in the Bay. But more research is needed, and Bill dedicated to finding an answer, as knowing the cause of their departure and subsequent return is vital to ensure the porpoise becomes a permanent resident again. The project hopes to answer several critical questions over time, such as whether the porpoises give birth annually or ever other year, and the reasons for the species range reestablishment.
To celebrate this success and to ensure the marine mammal's continued residence in the Bay, the National Wildlife Federation and Golden Gate Cetacean Research (GGCR) have partnered on a "Return of the Porpoise to San Francisco Bay" campaign. At this point, the National Wildlife Federation is the only major nonprofit supporting this cause, and Golden Gate Cetacean Research is the only organization conducting a study.
Harbor porpoises are notoriously shy and as a result not much is know about this creature, in contrast to its more charismatic relatives like the bottlenose dolphin. Porpoises lack the grinning beak and joyous, playful manner of dolphins, they rarely travel in groups larger than a dozen, and they are notoriously shy of people. Bill and his team have begun a multi-year assessment to document this population's abundance and distribution, as well as to examine site fidelity, habitat use, and reproductive timing. While the basic biology of the harbor porpoise is well known (mostly by examining strandings), relatively little work has been done on its social life, including mating behavior.
In just a few years, GGCR has amassed the world's first photo library of harbor porpoises, logging six hundred individuals and counting. Using these photos, they monitor individual porpoises over time, comparing scarring and distinct skin coloration to make identifications. On their website, GGCR calls for citizen scientists—i.e., anyone with a camera—to submit photos of any porpoise they encounter in the Bay. Citizen science plays a large role in developing their photo catalog, and now it's easier than ever to get involved, since people can snap and upload photos directly with their cellphones; just a few clicks and you can help advance porpoise, dolphin, and other bay research!
Click here for a short video about the animal's return, filmed with the California Director Beth Pratt-Bergstrom dressed as a porpoise and stopping by well-known landmarks in the Bay Area. Sitting in Lawrence Ferlinghetti's chair at City Lights Bookstore, shopping at Berkeley Bowl, and dancing on the ferry to Alcatraz in a porpoise costume are just a few of the highlights from her time as a porpoise.
Bill Keener's experience includes work as a field observer (vessel-based transects, photo-documentation, and data recording) for the harbor porpoise population study in the Gulf of Farallones National Marine Sanctuary conducted by Cascadia Research Collective from 1987-1989. He is an environmental lawyer and former Executive Director of the Marine Mammal Center in Sausalito, California, a facility dedicated to the rehabilitation and release of sick and injured pinnipeds, as well as the rescue of live, stranded cetaceans. Bill and his colleagues at Golden Gate Cetacean Research—Izzy, Szczepaniak, Jonathan Stern, and Marc Webber—have been observing marine mammals collectively longer than anyone in the Bay Area.
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