Without the oceans' phytoplankton, we should be unable to breathe. Primary consumers are animals that eat producers. On the Reef, primary consumers include members of the zooplankton which eat phytoplankton. Among these are planktonic arthropods and the larvae of relatively large sessile benthic animals such as sponges, and corals. Sponges and corals, along with tunicates, hydroids, and several types of worms that live in tubes, are filter feeders, living on plankton that they filter out of the water and on detritus, particles of dead organic matter.
Secondary consumers are animals that eat primary consumers.
For instance, small reef fishes, such as wrasses and tomtates, feed on benthic invertebrates. Some of the largest animals to be seen in the sanctuary are filter-feeding secondary consumers. The right whale lives on krill, arthropods that it filters out of the plankton. Other secondary consumers are spiny lobsters and slipper lobsters, of particular interest to divers as well as to the native octopus, which is equally fond of shrimp and crabs. Some animals are primary and secondary consumers at the same time because they eat both plants and primary consumers.