News, meetings and notices
Invasive jellyfish
What they are and how to report sightings
St. Johns River Water Management District biologists are asking for the public’s help in gathering information about an exotic predator that has returned to the Indian River Lagoon.
The Australian spotted jellyfish, which made its first appearance in the lagoon’s waters in 2001, has returned, according to biologists with the District’s Indian River Lagoon National Estuary Program.
Dozens of jellyfish sightings have been reported in the Melbourne and north Melbourne area since early June 2009, a spectacle that raises concerns about their potential effects on the ecology of the lagoon, North America’s most biologically diverse estuary. Lagoon officials are seeking information about the jellyfish from members of the public who may see them in area waterways.
Australian spotted jellyfish, Phyllorhiza punctata
Native to the Indo-Pacific region, the Australian spotted jellyfish is considered an invasive species in the United States. The species was first documented in parts of the Caribbean some 30 years ago, where it became established and still persists today. The jellyfish are voracious predators, filtering more than 260,000 gallons of water daily, and could potentially consume large numbers of fish eggs and microzooplankton in the lagoon.
The jellyfish range from the size of a human fist to as large as a basketball. They have white, semi-transparent to opaque bell shapes, with white spots on the bell. Frilly oral arms extending beneath the bell can release a mildly painful sting to humans.
Spotted jellies, Phyllorhiza punctata, can sometimes be mistaken for other species native to the lagoon, including the transparent moon jellyfish and the cannonball jellyfish, roughly the size of a melon and milky in color.
Millions of spotted jellyfish were observed for the first time in the northern Gulf of Mexico in 2000, along the coasts of Louisiana, Mississippi and Alabama. Commercial fishermen in Mobile Bay reported shrimp nets clogged with the egg-eating invaders within a 95-square-mile area of the Gulf. On the East Coast, they were recently documented as far north as North Carolina.
