Downward trend in loggerhead nesting continues
|A graph shows annual nest counts for loggerhead sea turtles on 27 beaches in the state from 1989 to 2008.|
Loggerhead nesting numbers in Florida went up in 2008 compared to 2007, but state officials continue to identify a long-term declining trend in nesting.
Annually, from about May through October, female loggerhead sea turtles nest on Florida’s beaches, including on Anna Maria Island’s shores.
An analysis of nesting data from the Florida Fish and Wildlife Conservation Commission shows that nest counts on the state’s core index beaches — certain designated beaches that provide counts every year — have decreased 41 percent from 1998 to 2008.
The number of nests reported from monitored beaches in the state was 28,074 in 2007 and 38,643 in 2008, that’s down from nearly 60,000 in 2006.
The decline in loggerhead nest numbers followed a modest increase that occurred between 1989 and 1998, according to the FWC.
From 1989 through 2008, the overall trend in loggerhead nesting is down approximately 26 percent.
The state’s index nesting data used in the analysis is based on nest counts made by hundreds of participants who survey turtle tracks and nests at specific Florida beaches, including walkers with Anna Maria Island Turtle Watch.
Each nesting area has people who hold a Florida Marine Turtle Permit and are trained in sea turtle nest identification. Participants also are required to follow a protocol to ensure nest counts reveal unbiased trends.
Scientists at the FWC’s Fish and Wildlife Research Institute use the nest counts from AMITW and other groups to track the stability of the loggerhead population. Florida accounts for more than 90 percent of the loggerhead nesting in the United States with a nesting aggregation considered to be one of the two largest remaining in the world.
For 2008, AMITW reported 147 loggerhead nests and a review of state data for Manatee County, which includes the Island and Longboat Key, shows nesting increased the past two years, but nesting is down from a high of 354 nests in 1995.
Additionally, loggerhead sea turtle deaths in Florida, as indicated by strandings, have more than doubled during the past decade based on information from the state’s Sea Turtle Stranding and Salvage Network database.
“Loggerheads have many threats to their survival. Artificial lighting on nesting beaches causes hatchlings from nests to crawl inland rather than toward the water,” The FWC said in a statement. “On developed beaches, coastal armoring meant to protect buildings from erosion has resulted in the loss of nesting habitat near natural dunes. Throughout the state's waters, collisions with boats are the most common identifiable cause of trauma in sea turtles that wash up dead on Florida beaches.”
Hurricanes may also impact nesting, according to the FWC.
The short-term impact of storms may involve waves washing out some nests. That was the case this year on Anna Maria Island and elsewhere.
The long-term impact of storms may not be known for decades. Loggerheads hatched on Florida beaches require some 20–30 years to reach maturity, recent storm impacts on turtle populations will not appear for many years.