E-Fauna BC: Electronic Atlas of the Wildlife of British Columbia

In British Columbia, Crossaster papposus eats the sea pen Ptilosarcus, sea slugs (opisthobranchs), bryozoa, sea squirts and bivalves. It may also attack other sea stars (such as Evasterias troschelli). In Scotland, C. papposus breeds from March to April; each sea star may spawn several times at intervals of two to ten days, shedding more than 2000 eggs at a time, 6000 altogether. The eggs (0.8 mm) are reddish-brown to clay colour and are fertilized externally. The lecithotrophic larva settles to the bottom after 18 days and attaches by a sucker. The mouth forms after about 38 days. Juveniles are often found among the tubes of the polychaete worm Phyllochaetopterus. C. papposus moves at a rate of 60 to 70 cm per minute. A well-fed Rose Star grew from 40 mm to 90 mm in one year. Richard Carlson at the Auke Bay Lab near Juneau studied a population for 17 years. He found that growth rates were quite slow, with individuals achieving a maximum diameter of 30 ern in about 10 years. Their principal prey item was the scallop Chlamys rubida. Crossaster papposus can live for at least 20 years. Mortality rates were low and recruitment of young was infrequent in that population. The scale worm Arctonoe vittata is commensal on C. papposus.