Richard E. Strassberg earned his Ph.D. in East Asian Studies from Princeton University.
Starfish are marine invertebrates. They typically have a central disc and five arms, though some species have a larger number of arms. The aboral or upper surface may be smooth, granular or spiny, and is covered with overlapping plates.bout 1,500 species of starfish occur on the seabed in all the world's oceans, from the tropics to frigid polar waters. They are found from the intertidal zone down to abyssal depths, 6,000 m (20,000 ft) below the surface.
Their nervous system is spread through their arms and their âbloodâ is actually filtered sea water. Size relative to a tea cup: Marine scientists have undertaken the difficult task of replacing the beloved starfishâs common name with sea star because, well, the starfish is not a fish.Itâs an echinoderm, closely related to sea urchins and sand dollars.heir nervous system is spread through their arms and their âbloodâ is actually filtered sea water. Size relative to a tea cup: Marine scientists have undertaken the difficult task of replacing the beloved starfishâs common name with sea star because, well, the starfish is not a fish.