Jellyfish are in contact with thousands of other aquatic organisms every
day. The biggest interaction with other organisms involves
predation, both with jellyfish as the predator and the prey.
Recall, jellyfish usually consume organisms
such as zooplankton, copepods, cladocerans, larvaceans,
and bivalves. They use their cnidocytes which eject nematocysts to
catch and kill their prey. This same mechanism is used as a
defense against their predators.
Common predators against Moon Jellyfish are
Ocean Sunfish, Loggerhead Sea Turtle, the hydromedusae, and the
scyphomedusa. They are also sometimes consumed by birds. In
some countries, such as China, Phillipines, Thailand, Malaysia, and
Indonesia, Jellyfish are considered a delicacy.
An importance of jellyfish recognized by
humans is their role in transformations of pelagic organic material
which is important for the productivity of the ocean.
Some fishermen do not appreciate the
presence of jellyfish, though, because of their role in depleting the
population of larvae of commercially important fish. Also, they
can cause an outbreak of algae blooms which are frowned upon by