It's happening so frequently, researchers are having a tough time keeping track.
Dolphins are dying by the dozens off the Florida coast from morbillivirus, which is similar to measles.
A member of the dolphin family is the pilot whale, and nearly 50 stranded themselves in the Everglades on Wednesday. Biologists are not sure why but say pilot whales usually swim in pods, so the mass may have followed one into dangerous territory.
"Once they come ashore, I think they really are in trouble because they are designed to be in deep water where the water buoyants them up," said Dr. Quinton White, executive director of the Marine Science Research Institute at Jacksonville University. "When they get in shallow water, they get compressed, they can't breathe, it gets them in respiratory distress, and before you know it, they're dying."
At least 10 have died. The others are swimming in about 3 feet of water.
White said these problems with marine life are of great concern, particularly with whales because they near the top of the food chain. White said it indicates the ocean is under stress.
"With increases in CO2, increases in water temperature, increases in the sea level, we've used and abused our ocean for so long that I think we're finally starting to see the proverbial canary in the coal mine," White said. "We've got problems. We need to start thinking of how we're going to address it."
White said that starts with humans and protection against pollution.
"People need to start paying attention to how they live their lives," he said. "And I know they hear that a lot, but we can do a lot of little things to conserve, reuse, recycle, particularly this time of the year. Think about what you're doing. Think about when you fertilize your yard. Think about your water use. Try to be a good steward of the Earth because it's the only one we've got."