The Jellyfish Explosion

Thousands of jellyfish washed ashore onto Florida's beaches in 2007.  The onslaught may be part of a "Jellyfish Gone Wild" scenario that is resulting in massive blooms of stinging jellyfish and jellyfish-like creatures in oceans around the world. 

When distributed in reasonable numbers, native jellyfish play important ecological roles.  But when their populations run wild, as in recent years, they have overrun some of the world's most important fisheries and tourist destinations.  The result is major damage to fisheries, fish farms, seabed mining operations, desalination plants and ships.  Their swarms also cause injuries, even deaths, to water enthusiasts. 

Huge jellyfish swarms are not unnatural, they have occurred for millions of years and would continue to occur in some locations even without the environmental stresses imposed on the ocean by the human population.  Scientists believe the swarms occur when environmental factors favor their survival: the concentration of predators and competitors, food availability, currents and temperature, salinity and oxygen content of the water. 

Today's global warming trend, the abundant human population and its affect on the ocean environment, especially the transport of a species such as the comb jellyfish into a new environment where it has no natural predators, are some of the reasons jellyfish blooms are increasing in frequency and location. 

Those blooms come at a heavy cost environmentally.  They crowd out other species by eating their eggs and larvae and competing with them for the same food, such as zooplankton.  As a result, fishermen see huge declines in fish, anchovy and other populations while algae populations may erupt in massive blooms because there is nothing around to eat it and keep it in check. 

Aside from discouraging tourists and damaging fishing operations, jellyfish blooms have hampered industrial operations such as marine diamond mining and desalination plants, clogged the intake pipes of big ships and forced a number of nuclear plants around the world to temporarily shut down.  For more information about jellyfish and their role in the ocean environment, visit this site.

— Written by By Diane Banegas; Photo Credit: Erion Cuko, Jacksonville, Fl.

• More Jellyfish News