fish kill
© Lexey SwallAn unusual arrival of offshore fish, some of them dead, littered the shoreline Monday in North Naples. The Florida Fish and Wildlife Conservation Commission is testing water samples and shark tissue to determine the cause of the dark water and fish kill. Scientists suspect low-dissolved oxygen, possibly as a result of a dying algae bloom, are killing the fish. The health department has not advised swimmers to stay out of the water.

Dead fish have been washing up on the beaches at Naples since Monday.

And commercial fishermen out of Madeira Beach and marine scientists have been conducting a survey of fish with sores and deformities in the Gulf of Mexico since the first week of July.

The exact cause of these problems hasn't been pinpointed yet, and the reports have been isolated dating to the winter.

But two possible reasons being mentioned are the Gulf oil spill last April and a "dead zone'' devoid of oxygen.

The St. Petersburg Times reported last week that three 10-day trips into the Gulf from Madeira Beach and Panama City that departed July 6, July 8 and July 18 were searching for fish that might have some sort of disease. They are catching and checking fish from the Keys across to Texas.

The Times report said red snapper and vermilion snapper caught by fishermen showed "wounds straight through their muscle tissue.''

Meanwhile, the Naples News reported Monday that dead fish were on the beaches between Doctors Pass and Wiggins Pass.

Collier County officials have sent dead fish and water samples to the Florida Fish and Wildlife Research Institute in St. Petersburg for testing.

The News reported that fish species that are uncommon along beaches were swimming in "rust-colored'' water with little or no oxygen, possibly because of an offshore algae bloom that ate up all the oxygen.

The story said there were dead lobsters balled up together in Clam Pass, and Vanderbilt Beach was loaded with cowfish, toadfish and eels.

Red tide wasn't mentioned in either of the reports, however.

We all remember the large dead zone off the St. Petersburg-Clearwater area in 2005 after one of the most severe outbreaks of red tide on record on the Gulf Coast.

And there have been dead zones in the Gulf south of the Mississippi River for years.

But reports of fish with lesions, deformities and discoloration are rare.

The BP oil spill has been mentioned as the cause for many unusual occurrences in the past year off the Tampa Bay area, from whale sharks off Sarasota to changing baitfish patterns to an influx of goliath grouper. But proving a connection to the oil spill is difficult.

Hopefully, these reports of dead and diseased fish will be limited.

But the health of the Gulf is always a concern.