Saturday, April 23, 2011

Florida's Dead Shark Mystery: 15 small sharks wash ashore along west coast

Every now and then we get mysteries than can initially defy explanation or fuel the imaginations of those seeking easy justification of conspiracy or doomsday theories. With regards to the oceans, there have been coral die-offs, algal blooms, whale and dolphin beachings, and mass fish deaths that occur from time to time. And this week, one more strange event occurred that, at this moment, has marine scientists scratching their heads.

Sharks have washed ashore along the northern beaches of Manatee County, Florida. This is an area along the western or Gulf of Mexico side of Florida, south of Tampa. The dead sharks, fifteen so far, consisted of bonnethead, blacknose, and sharpnose sharks - relatively small sharks that cruise coastal waters.

As reported by Bay News 9, marine scientists from Florida's MOTE Marine Laboratory do not believe the sharks succumbed to any effects from the Gulf oil spill because the normal range and travel patterns of these particular species of shark would have precluded them from getting in harm's way. However, it is nonetheless unusual for so many sharks to be found dead within a specific area - the occasional shark, yes; but fifteen sharks in a week, no.

"There were no real indicators of what went wrong with them," said Dr. Nick Whitney, Staff Scientist for the Center for Shark Research at MOTE Marine Laboratory. "There are no obvious signs of damage from fishing or net damage or anything like that."

Tissues samples were taken for analysis to determine whether the sharks died due to the effects of a red tide - an algal bloom that can carry dimoic acid which has been shown to cause neurological disruptions and death in seals and fish. Recently, an isolated mass die-off of sardines in Manhattan Beach, California left the harbor with literally tens of thousands of dead fish either floating on the surface or piling up on the harbor bottom.

Being the shark admirer that I am, I found this all very disappointing; I have dived with bonnethead sharks and they are beautiful, delicate sharks - petite relatives to the larger hammerhead species.

I also found it a bit ironic as I had just recently read an article that had listed the "top five unfounded health hysterias." The editors of the Big Think blog ran their self-appointed five and four of them revolved around over-hyped perceived threats from autism-causing vaccines, fluoridated water, the SARS virus, anthrax . . . and number five was shark attacks.

Poor sharks - lumped together in our over-worked imaginations with other obscure or statistically remote diseases or medical conditions. And yet the great malevolent ocean monster is, itself, truly susceptible to mysterious maladies that can deprive the ocean of an important member of the marine community.

It's not easy being a shark.

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