What Divers Should Know About Sea Star

Sea stars, members of the taxonomic class Asteroidea, are a common and captivating sight for divers across all the world's oceans. These invertebrates are truly global citizens, thriving from warm tropical zones down to frigid polar regions, and encountered from the intertidal shallows down to impressive abyssal depths of 6,000 meters. With nearly 1,900 identified species, their presence graces almost every seabed.

Typically recognized by their iconic star-polygon shape, most sea stars feature a central disc from which five arms radiate. However, considerable variation exists, with some species displaying anywhere from six or seven up to fifteen arms, and even over fifty in certain Antarctic forms. Their upper surfaces, which can be smooth, granular, or spiny, often boast vibrant hues of red, orange, blue, grey, or brown, adding splashes of color to the marine environment.

Observing a sea star, you'll note its slow, deliberate movements. They utilize an intricate hydraulic system to operate their tube feet, which are essential for locomotion, adhesion, and manipulating their opportunistic benthic invertebrate prey. Should a sea star lose an arm, perhaps as a defense mechanism, it possesses the remarkable ability to regenerate damaged parts, a testament to their resilience and adaptive nature in the marine world.