Large numbers of huge Australian jellyfish have been found in the waters of the Gulf of Mexico near the southern United States.
Scientists want to know more about them and what long-term effects their presence may have.
A jellyfish is an unusual sea creature.It is not a fish.
It does not have a backbone.It has a soft body shaped like a bell.
And it has long string-like structures called tentacles.
There are more than two-hundred different kinds of jellyfish in all of the world's oceans.The come in all shapes and sizes.
Jellyfish are often a problem for people swimming at the beach because some of them can sting.
Some jellyfish stings can be very painful.But most jellyfish are harmless to humans.
Tens of thousands of spotted Australian jellyfish have washed up on beaches off the southern coasts of Alabama,Florida,Louisiana and Mississippi.
Observers say they can easily be seen from the air.
Scientists say the jellyfish have grown two times their normal size.
They are more than one-half meter across and weigh,at least eleven kilograms.
The huge creatures are causing problems for people living near coastal waters of the Gulf of Mexico.
Swimmers are avoiding the beaches.And the jellyfish are getting caught in fishing nets and in boat engines.
Scientists say the jellyfish may have a serious effect on the environmental system in the Gulf of Mexico.
Scientists fear the jellyfish are eating the eggs and young creatures of the area's fish,shrimp and crabs.
They say this may harm the valuable fishing industry in the area.
Spotted jellyfish are native to Australia.
They have been moving to the Caribbean Sea for twenty years.
But this is the first time they have been seen so far north.
They invaded the Gulf of Mexico in early June.
Experts believe the jellyfish were caught in unusual waves that moved them north to the Gulf of Mexico.
Scientists in Mississippi and Alabama are doing research to find out more about the invaders and how much they eat.
They hope that increased rainfall or cold weather will kill or control the jellyfish.
Scientists do not know if the jellyfish will survive the winter.
If they do,their effect on the environment of the Gulf of Mexico could be an even bigger problem next year.