(Ft. Myers, Florida News-Press)
Massive Estero Bay
fish kill a mystery
It's a mystery: Something is killing mullet in
Estero Bay, but nobody knows what.
Katie McFarland, an FGCU graduate
student, first saw large numbers of dead
mullet floating in the bay and washed up
along the shoreline Friday.
Saturday morning, McFarland took another
trip onto the bay to take water samples
and saw hundreds of mullet between
FGCU's Vester Field Station and New Pass.
"From what I've heard, it's the whole bay,"
she said. "I've yet to see anything but
mullet. It's crazy, the numbers of them."
Soon after he made that comment,
McFarland found one dead Atlantic
spadefish.
One suspect is red tide, a natural
phenomenon that occurs when the toxic
single-cell alga Karenia brevis undergoes a
population explosion, or bloom.
To determine the strength of a red tide,
scientists take water samples and count the
number of Karenia cells per liter of water.
Fish can start dying when concentrations
are "low," 10,000 to 100,000 cells per
liter; the effects of medium concentrations,
100,000 to 1 million cells, are "probable
fish kills."
According to the state's latest red tide
status report, a Karenia bloom stretches
for 30 miles along the shore from southern
Lee County to northern Collier County and
30 miles offshore. Water samples taken
Tuesday showed medium concentrations at
Lighthouse Beach on Sanibel and low counts
at Lynn Hall Park and Lovers Key State
Park.
"Satellite imagery shows that the bloom we
had up in Sarasota County worked its way
down off Captiva and kept heading south,"
said Gary Kirkpatrick, manager of Mote
Marine Laboratory's Phytoplankton Ecology
Program. "Clearly it's in the area, but I can'
t tell what's killing the fish without having
somebody do a toxin analysis. It seems
likely that it's red tide."
But if it's red tide, which can kill any fish
species, as well as birds, marine mammals
and sea turtles, why is it killing almost
exclusively mullet?
"I don't know why mullet, unless it got into
an area of the estuary that was highly
loaded with mullet," Kirkpatrick said. "It
doesn't make real good sense."
Another possible reason for the fish kill,
McFarland said, is a bloom of a different
kind of algae that is depleting the water of
dissolved oxygen.
As of Saturday, no dead fish have been
reported outside Estero Bay.
"I've been fishing every day, from Chino
Island to Boca Grande, and it looks good
up here," said Capt. Shane Dooley, a Pine
Island fishing guide and commercial
fisherman. "Everything's clean. There's
nothing bad."
Jimmy Jensen, co-owner of Jensen's Twin
Palm Cottages and Marina and Jensen's on
the Gulf on Captiva, said he hasn't heard
reports of dead fish since mid-October.
"We've got nothing at all," he said. "I haven'
t heard anything from the bay side or the
Gulf side."
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