Sea Stars Of The Pacific North West


Welcome to Sea Stars of the Pacific Northwest. This site includes descriptions of 30 species of sea stars encountered from the intertidal zone to a depth of 30 m (100 ft) on the Pacific coast of North America from northern California, Oregon, Washington State, British Columbia and southeast Alaska.
I've been interested in sea stars since 1969 when I started diving while attending the University of British Columbia. During my first dives near Vancouver I observed many different types of sea stars and found them fascinating. They were diverse, abundant and often extremely colourful components of bottom communities. For my B.Sc. thesis I studied the predatory MORNING SUN STAR Solaster dawsoni and made many dives observing its behaviour and that of its prey, which are mostly other sea stars.
There are several excellent reference books that include Pacific coast sea stars. The best single reference is Sea Stars of British Columbia, Southeast Alaska and Puget Sound by Philip Lambert. Phil's book is the ultimate bible for anyone interested in this group of echinoderms, presenting detailed information about many aspects of sea star biology and individual descriptions for 43 species.
The intent of this site is to supplement existing references with additional pictures, field observations and the results of lab studies. Divers, especially those with still and video cameras, are often witnesses to behaviours never seen before and can add invaluable information to our knowledge of sea stars. I welcome you to submit your observations and pictures, especially if you come across anything unusual.
Sea stars are found virtually everywhere in the marine environment. Beach walkers will find the greatest variety along rocky shores at low tide; as many as a dozen species or more. Large tidal pools are especially rich habitats full of colourful marine life including sea stars. An additional handful can be seen on sandy or muddy substrates in bays, often crawling about in eelgrass beds.
Scuba divers have the advantage of exploring the sea bed below the intertidal zone and encountering many conspicuous sea stars. Most live on bedrock or boulder substrates, although a number of fascinating species prefer sand or mud habitats. Digital underwater photography offers the ideal way to document sea stars. And underwater video is the perfect tool to record their interesting behaviours.
Most sea stars in the PNW are relatively easy to identify in the field, based on the number, proportion and size of their arms, their colour and the shape of the skeletal plates and spines. A few look-alikes may cause confusion but specific tips are included to sort these out.