From the South Florida Sun-Sentinel in the USA:
Sea turtle nests in South Florida hit 10-year high
Thousands of loggerhead turtles nested in Broward and Palm Beach counties in 2010 but ran into problems on land
By David Fleshler, Sun Sentinel
5:15 p.m. EST, January 30, 2011
Sea turtles nested in the highest numbers in 10 years in South Florida this season, a hopeful sign for the giant reptiles that must evade sharks, shrimp nets, cargo ships and commercial fishing lines to lay eggs on the region’s beaches.
But hazards on land — both natural and human — wasted the efforts of many female turtles to continue this ancient reproductive ritual. The unusually hot, dry weather of early summer led to many nest failures, either by causing the dry sand to cave in or by ruining the eggs with heat. And city lights continued to disorient many hatchlings, causing them to crawl inland, where they got caught in storm drains, run over in parking lots or became prey for birds and raccoons.
Loggerhead, green and leatherback turtles dug 2,565 nests in Broward County in 2010, representing an increase of 641 from the previous year, with the highest density found in Hillsboro Beach, followed by Pompano Beach. In Palm Beach County, final figures are not in yet. But reports in the north of the county, from Lake Worth through Jupiter, show sea turtles dug an impressive 16,073 nests, reversing a long decline in nesting, with loggerheads accounting for the majority of nests, said Paul Davis, the county’s sea turtle coordinator.
“We’re expecting the final count of loggerheads to be similar to 10 years ago, when nesting was at a peak,” Davis said. “That’s promising, but it’s going to take several good years to turn it around.”
Florida is particularly important for loggerhead turtles, which weigh an average of 275 pounds, travel thousands of miles in the course of a year and feed on jellyfish, squid, clams, crabs, corals and sponges. Florida and the nation of Oman on the Arabian peninsula account for 80 percent of the nests.
No one knows why nesting rebounded after years of stagnation and decline. Conservation efforts have required some shrimp boats to install devices to prevent sea turtles from getting caught in nets. And state and local governments have taken steps to reduce beach lights, which disrupt nesting. But biologists say it would be difficult to attribute a one-year peak to recent conservation work.
“Because turtles take so long to reach sexual maturity and reproduce for so many years, it’s way too soon to tell,” said Anne Meylan, a biologist with the research arm of the Florida Fish and Wildlife Conservation Commission.
But despite a sharp increase in the number of nests in Broward County, there was a 14.9 percent drop in the live hatchlings. Biologists blame the unusually hot, dry weather of early summer. Female turtles have a difficult time digging nests in dry sand, which continues flowing back into the hole they’re trying to dig. And the increased heat prevents many eggs from developing and hatching.
A similar problem was reported in Palm Beach County. “Close to 200 of our nests didn’t hatch half their eggs because they literally cooked,” said Kirt Rusenko, marine conservationist at Gumbo Limbo Nature Center in Boca Raton, who supervises sea turtle protection in the area. “And it was too dry for females to lay eggs.”
Meanwhile, the hazard of artificial lights on shore caused heavy casualties among hatchlings. In Palm Beach County, where artificial lights along beaches have been strictly limited, the culprit is sky glow, the reflection on the sky of inland lights, said Davis, the county’s sea turtle coordinator.
In 2010 there were a record-breaking 436 incidents in which turtles were disoriented by lights, events that can be detected by tracks in the sand and the discovery of hatchlings in parking lots and other places they don’t belong. These incidents involved 11,478 hatchlings and 46 adults, according to preliminary figures.
The widespread practice of trimming sea grape bushes along the beach has worsened the problem by exposing beaches to light. “It’s been happening for 10 years,” Davis said. “Oceanfront property owners want to be able to see the ocean, and the state has allowed this to happen.”
In Broward County there are more exposed lights on the beach, and there’s a running conflict between conservationists and city authorities over what to do about them.
Richard WhiteCloud, who leads a Broward sea turtle rescue group called Sea Turtle Oversight Protection, said Fort Lauderdale is the hotspot for disorientations, with his group logging 6,418 disoriented hatchlings and 118 confirmed dead. He said the city failed to comply with the law protecting sea turtles from lights by allowing so much construction along the beach in the past few years and failing to rein in the lights that blaze along the beach at night.
Fort Lauderdale spokesman Matt Little said the city has been working hard on education and enforcement to reduce glare during nesting season. Last year the city assigned two code inspectors to the issue, and the city has active enforcement cases against 36 properties, he said.
“Significant progress has been made toward the overall reduction of light emanating from beach properties,” he said.
David Fleshler can be reached at dfleshler@SunSentinel.com or 954-356-4535.
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