A group of dolphins swept from their aquarium tank by Hurricane Katrina have grouped together in the Gulf of Mexico. Surprised scientists who thought they had died, now want to bring them home.

The dolphins' home, destroyed by Katrina, had been a nine-metre-high tank at the Port of Gulfport's nearly 50-year-old Marine Life Oceanarium.

Zookeeper Emily Schultz works with Andre, the California sea lion, at the Memphis Zoo. (AP Photo/The Commercial Appeal, A.J. Wolfe)

Three of eight dolphins were born at the aquarium. Because the dolphins have spent much of their lives in captivity, they may not have developed the survival skills necessary to avoid predators and boat traffic, scientists from the U.S. National Oceanic and Atmospheric Administration said.

The mammals appear to be significantly underweight and have several wounds, said Teri Rowles, lead veterinarian for NOAA's Fisheries Service.

The dolphins will be taken to nearby saltwater pools provided by the U.S. navy for medical evaluation and treatment.

Nineteen sea lions also were missing from the Oceanarium. One of them, Andre, a 115-kilogram sea lion, has found a temporary home at the Memphis Zoo. The storm washed him from his pen and he wandered for 11 days before being found behind a casino. Andre lost about 45 kilograms but specialists said he was otherwise in good shape.