Red starfish (Echinaster sepositus)

Starfish (class Asteroidea) are a group of echinoderms with star-shaped and often brightly colored bodies. Most species have five arms radiating from a central disc. Starfish range from one centimeter (0.4 inches, Asterina gibbosa) to one meter (3.3 feet, Freyella remex) across the body. In some regions Crown-of-thorns starfish (Acanthaster planci) infestations pose one of the most significant threats to coral reefs.

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This supplemental online resource accompanies the book Scuba Diving Hand Signals by Lars Behnke, available on Amazon.