Light micrograph with dark-field illumination of a crab megalops larva from the North Sea in the German bight. The zooplankton community in the surface waters of the ocean contain larvae and juveniles of countless species, crabs are among them. Adult crabs are easily recognizable to most people. They are also associated with living on the sea floor or in the intertidal zone. Larval marine crabs typically spend their juvenile lives afloat in the world's ocean currents. There they pass through several developmental stages before metamorphosing into an adult animal. The spiny crab zoea ultimately changes into a crab megalops. Zooplankton serve as important food resources to countless species of fish and marine invertebrates. Magnification: x50 when printed at 10 centimetres wide.