Pelagic Red Crabs

A small but very important aquatic animal lives in the shallow water of the Pacific Ocean along the western continental shelf of the Americas. The habitat of pelagic red crabs (Pleuroncodes planipes) ranges from southern California to as far south as Chile.

Biologists could not understand how there could be a large adult population of pelagic red crabs living along the coast of southern California. They were puzzled by the fact that when the crabs reproduce, their tiny young, which we call larvae, were immediately swept far out to sea by the California Current. The mystery was solved when scientists discovered that the larvae are carried back to the coast by deep undercurrents.

Aquatic creatures such as whales that feed on plankton (tiny sea creatures) eat the red crab larvae. When the pelagic red crabs mature, they provide food for marine mammals and fish. They are the preferred food of tuna, and for that reason, they are sometimes called tuna crabs. Loggerhead sea turtles dine on pelagic red crabs. Sometimes these crabs are washed up on shore where they become prey for seabirds. Sea otters, a keystone species of the California coast, also feed on pelagic red crabs.

Looking at the list of predators you might question how these crabs survive. They reproduce in large numbers, and it seems that their purpose is to supply food to many larger creatures. They are what scientists call primary producers at the bottom of the food chain providing energy for many important species. That role is hard to explain by evolution and “survival of the fittest.” We think it’s part of God’s design. Without pelagic red crabs, many other creatures would not survive.
© Roland Earnst

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