copepod

noun

1. Any of very many small crustaceans of the subclass Copepoda; they are widely distributed and ecologically important.

   “To eat, the whale takes a wide-open gulp of water and closes its jaws to a slit so that as it pushes its tongue forwards and upwards, water is forced through the baleen while the copepods, krill and other animals it likes to eat remain in its mouth.”