Mr. Purple Star Fish at low tide, San Juan Islands

Mr. Purple Star Fish at low tide, San Juan Islands

The Ochre Sea Star, also known as the purple starfish, is a common sight in the tide pools along the Pacific Coast. These sea stars, scientifically named Pisaster ochraceus, exhibit a range of colors from purple to orange to reddish-brown. They typically have five arms, though variations with four to seven arms can occur. Found from Prince William Sound in Alaska to Baja California, Mexico, they thrive in the middle to low intertidal zones on rocky shores and can survive up to eight hours out of water.

These sea stars are notable for their resilience and adaptability. They can tolerate significant changes in their environment, including temperature fluctuations and desiccation. Their bodies are covered in white spines called ossicles, which help keep them free of parasites. The aboral side of their body is where these spines are located, while the oral side houses their mouth and tube feet. These tube feet are essential for movement, capturing prey, and clinging to surfaces.

Ochre sea stars play a crucial role in their ecosystem as a keystone species. They prey on various species such as barnacles, mussels, snails, limpets, and chitons. By controlling the population of California mussels, they ensure that other species have space to thrive on the rocks. Their feeding process is fascinating; they use their arms to envelop prey and their tube feet to pry open shells, then evert their stomachs to digest the prey externally. This process can take two to three days, highlighting their unique and vital role in maintaining the balance of their habitat.

Additional Links:
Crystal Seas Kayaking San Juan Islands Photo Gallery
Crystal Seas Kayaking - Guide to the San Juan Islands
San Juan Islands Kayak Tours and Bike Tours with Crystal Seas Kayaking