CRUSTACEA/COPEPODA
As the largest and most diverse class of crustaceans, copepods live almost everywhere fresh and salt water exists. They include more than 14,000 species worldwide. In terms of total biomass (total weight), copepods are more plentiful than insects (which include more species but fewer individuals).

Commonly microscopic in size, copepods are considered zooplankton because they are free-floating organisms that primarily move passively with the force of water currents.

Because they are so small, copepods can feed only on bacteria, diatoms, or other unicellular organisms. In female adult copepods, one or a pair of egg sacs are attached to the base of the abdomen.

In the ocean, copepods are the largest source of protein. Many fish, including important commercial species caught by anglers, depend on copepods as a food source, as do certain whales.