a ochre starfish purple sea star

asteriidae asteroidea beach british britishcolumbias california canada change climate coast coastal coastline columbia crevices diverse dock echinoderm ecology ecosystem fish five forcipulatida found health indicator intertidal island keystone life marine mussel northwest ocean ochraceus ochre pacific pisaster pool population predator purple radial rays sea shore shoreline species star starfish sunshine symmetry syndrome thormanby tidal tide vibrant wasting wildlife