Negative Growth and Longevity in the Purple Sea Urchin Strongylocentrotus purpuratus (Stimpson).
Purple sea urchins were tagged, measured, and placed in a tidepool at Sunset Bay, Oregon. After 1 year, many animals had decreased in size. Accordingly, size is not necessarily a reliable index of age in Strongylocentrotus purpuratus; however, it is possible to conclude that these animals are relatively long-lived.
Ebert
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