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Signs of global warming noticeable
in Keys
By Ben
Iannotta
Finally, it's
starting to look and feel like springtime in the Keys. The tarpon are
rolling predictably each morning in the backcountry channels, and soon —
maybe today — they'll grace the shallows in better numbers.
Permit have
been all over the Atlantic flats, most interestingly east of Key West
where one expects to see fewer of them. They're fattening up on crabs
before gathering offshore to spawn.
As if to
confirm that we've turned the corner toward summer, the sun is starting
to burn a soft, spring-time haze over the backcountry.
It's not just
the fish that are reacting to the weather. A white-crowned pigeon
scooted low over the mangroves the other day. Within weeks, flocks of
them will be gobbling up the sea grapes that are just now budding in the
Keys. Broad-winged hawks, like the one that swooped down to attack a
giant centipede, will soon head north.
All appears to
be well in the wild side of the Florida Keys; a place only a soulless
fellow could summarize as an "ecosystem," and only a hermit could argue
doesn't have a "change of seasons."
Now, if you're
the type who doesn't like biologists and newspaper writers stepping on
your natural buzz, please stop reading.
John
Weishampel, a forest ecologist turned sea turtle scientist at the
University of Central Florida, reported last week that loggerhead
turtles on Florida's Atlantic coast are laying eggs 10 days earlier on
average than they did 15 years ago.
Over the same
years, the average nearshore water temperatures climbed by about 1.5
degrees Fahrenheit. A coincidence? Only a fossil-fuel lobbyist would
think so.
Weishampel and
biology professor Llew Ehrhart and researcher Dean Bagley worked with
UCF students to analyze nesting records for a 25-mile stretch of Florida
beach from Patrick Air Force Base south to Sebastian Inlet.
That area
accounts for one in four of all loggerhead nests in the United States.
Many of the loggerheads seen each summer in the Keys are turtles that
laid eggs in April and May in the sands of the mainland, Weishampel
says.
The finding
that global warming is causing one of Florida's most famous sea animals
to change the timing of its reproduction is huge. "This is the first
time, to my knowledge, that this has been found in subtropical
creatures," Weishampel says.
So, maybe you
don't think loggerheads are all that cute and you really don't care when
they lay their eggs. The finding should matter to you because
loggerheads almost surely are not the only subtropical creatures that
are responding to global warming this way.
We've learned
this first about loggerheads because they have an adoring and
scientifically minded fan club. It helps that sea turtle reproduction is
relatively easy to study because they conveniently crawl ashore to dig
nests.
The last time
I checked, no one had ever scientifically documented a tarpon spawning,
let alone accumulate a 15-year record of the precise timing of the
event.
The bottom
line is that what might appear to anglers as a wonderfully normal spring
season could actually disguise changing reproduction patterns for
permit, tarpon and their food sources.
Why does it
matter when creatures change their reproduction timing by a few days
over a decade and a half?
"I kind of
think of it like a symphony," Weishampel says. "The animals are the
instruments. If they're not coming in at the right time, you've got a
screwed up concert."
Those sea
turtle hatchlings will need to eat tiny crabs and shrimp when they crawl
out to sea, but if the crabs and shrimp aren't reacting the same way to
global warming the turtles could be left without enough food, Weishampel
warns.
Even worse,
the sex of a sea turtle hatchling is determined by the temperature of
the sand in which it developed. If mama sea turtles can't find sand of
the right temperatures, they won't be able to ensure a proper ratio of
males and females in the population, Weishampel says.
Global warming
is obviously a long-term problem. But there are some things that can be
done in the short-term. In the case of sea turtles, the finding could
mean that regulators should change the timing of temporary bans on beach
lighting, which confuses nesting turtles, and driving on the beach,
which needs no explanation.
Who knows what
opportunities we're missing to protect sport fish because we just don't
know? That's something to sober you up.
biannotta@aol.com
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