BRADENTON — A scientist at Mote Marine Laboratory has reported unusually large fish closer to shore than is typical along Florida’s west coast, and plans to study whether it might be related to the Gulf oil spill.
“This is pretty unusual,” said Robert Hueter, senior scientist and director of the Center for Shark Research at Sarasota’s Mote Marine Laboratory.
About a month after the Deepwater Horizon oil spill began in April, large sharks began appearing along the shoreline out to about 25 miles, Hueter said Thursday. Over the course of the next couple of months, he had reports of everything from very large tiger sharks to species like blackfin tuna, mahi mahi, wahoo and sailfish.
“Most of those, you usually have to go out 60 miles or more, and people are catching them within 20 miles,” said Hueter.
Whale sharks were very close to shore all summer, he said; the huge fish, which primarily feed on plankton and microscopic plants and animals, can reach 40 feet or more in length.
“It led to a hypothesis that these animals have possibly been displaced by the oil in the northwestern Gulf, where we know these species do reside in the summertime,” Heuter said.
Or, the phenomenon might be due to something else, which has prompted Mote scientists to investigate. The marine lab is planning a workshop on the topic and a research cruise, among other things, scientists said.
Other researchers reported similar findings.
“Fish usually found 30 miles out are occurring closer than 10 miles,” said Ernst Peebles, a biological oceanographer and associate professor at the University of South Florida College of Marine Science, in St. Petersburg.
Unusual distributions of fish are common, however, he emphasized.
“Everybody’s going to attribute things to the spill, but it’s very hard to say whether it’s causing these unusual fish distributions,” said Peebles.
Fishermen contacted by the Herald had varying views. Several from the Bradenton-Sarasota area had noticed an unusually large number of whale sharks, but had not seen any other type of large fish nearer to shore than has been typical in the past.
Capt. Kim Ibasfalean, who operates a charter boat business near Bradenton, said she had seen an unusual number of large, bonnethead sharks.
“They’re normally really little, the ones I see, I’m talking a foot-and-a-half,” she said. “And, I’m seeing three-foots.”
She’s also “hip deep” in big blue crabs, she said.
Normally, she sees crabs smaller than her hand, but now, she’s seeing much bigger ones — everywhere. She thought it might be attributable to a severe winter, which caused fish kills that the crabs cleaned up by dining on the carcasses.
Farther north in Tarpon Springs, near Tampa, fish have been a little bit out of their normal habitats, said John Cox, owner of Cox Seafood.
“A lot of those fish are smart enough to avoid the oil, and really, bluefin tuna are really fast swimmers,” Cox said. “They feed in clean water, they’re going to search out clean waters.
“They’re smart fish, if they can get away from it, they’ll get away from dirty water,” he added. “During the winter, they migrate toward warmer waters, they will move out of where they were, and move to cleaner waters; ... it’s like Red Tides. We see a tremendous amount of fish in Red Tide. We also see fish that outrun the Red Tide to get away from it.”
Gulf currents shift back and forth, and with them, big fish may move closer or farther away from shore, said Roger Zimmerman, laboratory director at the National Oceanic and Atmospheric Administration’s National Marine Fisheries Services facility at Galveston, Texas.
“Twenty miles is close, it must mean pretty good fishing for the recreational fishermen,” he said when told of reports of unusually large fish close to the Florida west coast.
“I would say it’s unlikely that it’s associated with the oil, and the oil spill, but I agree with him (Mote’s Robert Heuter), you can’t leave out that possibility,” said Zimmerman.