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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.  Since our study’s inception, observations have resulted in an image database of recognizable animals. This is the most comprehensive photo-identification effort undertaken for this species.  

We hope to answer several critical questions over time, such as whether the porpoises give birth annually or every other year, and the reasons for the species range reestablishment.

This research is authorized by NOAA Fisheries
Letter of Confirmation #20386.

Porpoise mother with her calf

Porpoise with prominent scar

  • SF Bay Area:  look for single animals or small groups in the bay, especially near high tide as they move through the Golden Gate underneath the bridge.

A very unusual porpoise we discovered in the Bay has bright white skin, which has allowed “citizen scientists” to report their sightings to us, making this animal the one of the most frequently sighted individual porpoises, seen 10 times since April 2011. Visit our Publications page for a copy of the scientific note we wrote about this animal.

Illustration by Uko Gorter

Harbor Porpoise Project

​Harbor porpoises (Phocoena phocoena)have returned to San Francisco Bay after an absence of approximately 65 years. 

We 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.  

Harbor Porpoise Facts: 

  • Scientific namePhocoena phocoena​
  • Length:  4.5 - 6 ft
  • Weight:  100-150 lbs, female slightly larger than males
  • Lifespan: 10-12 yrs on average, but up to 20 yrs
  • Calves: single calves are born usually in June-July after a gestation of 10.5 months, and remain with the mother until the following Spring
  • Diet: small schooling fish such as anchovy and herring, plus squid.
  • Range: Cool temperate waters along the coasts of the North Pacific, North Atlantic, and the Black Sea.               In California they occur north of Pt. Conception 
  • Population: approx 40,000 in California 
  • Conservation status: vulnerable, but not endangered​​


Field Studies of Porpoises, Dolphins & Whales