Eleven more whales were found dead in the lower Florida Keys on Dec. 8, believed to be a part of a pod of 51 pilot whales that were stranded there last week, according to Reuters.

Local police said the chances of finding the remaining whales alive are not good.

The pod of 51 pilot whales were first seen stranded at Florida Everglades National Park on Dec. 3. Despite rescue attempts by multiple scientists, ten whales died the following day, and another was confirmed dead on Dec. 5.

Eleven more whales were found this weekend about six miles north of Sugar Loaf Key. In total 22 have been confirmed dead, the U.S. Coast Guard said in a statement.

"Given our knowledge of past mass pilot whales strandings, the outlook for finding the remaining whales alive is bleak," the Coast Guard said, according to Reuters.

The Coast Guard confirmed 29 whales last seen on Dec. 6 remain missing.

Experts have so far not confirmed why the whales were beaching themselves in the Florida Keys. They're expected to study samples from the 11 whales found this weekend to determine the cause of death.

Scientists believe biotoxins or "red tide" could be the reason the whales were beaching themselves, according to Reuters.

Some dead whales were found to have empty stomachs, meaning they might have been of poor health before beaching themselves.

Pilot whales usually live in pods of 20 to 90, and will not leave sick or dead member behind, according to Reuters. They live on squid, octopus and fish and cannot survive long in shallow water.

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