Common Sea Star

<em>Asterias rubens</em>, the common sea star, is an echinoderm in the family Asteriidae, order Forcipulatida, widely distributed across the northeastern Atlantic and adjacent seas, with records from Denmark, Norway, Sweden, and Turkey. This species inhabits a broad range of subtidal and intertidal substrates including rocky reefs, sandy bottoms, and mussel beds, from the shoreline to depths of several hundred meters. <em>Asterias rubens</em> is an active predator, feeding primarily on bivalves such as mussels and oysters, which it opens using sustained arm-pull force combined with eversion of its stomach directly into the prey. It typically has five arms and is often orange, yellow, or brown in color. The species is listed as Least Concern by the IUCN, and populations are generally considered stable, though outbreaks can cause significant economic damage to shellfish aquaculture. Biological traits for this species remain poorly documented in the scientific literature in terms of standardized averages for lifespan, arm span, and weight across its full geographic range, though it is well studied as a model organism in marine biology and developmental research.