The number of returning nesting females in the population and favorable climate conditions in the year or two prior to the nesting year are strongly related to the number of nests produced by these animals in a given year, researchers with the National Oceanographic and Atmospheric Administration said Monday.
Fishery biologists at NOAA's Northeast Fisheries Science Center used annual nest counts from Florida and climate data in turtle-nesting population models to project future nesting trends in the Northwest Atlantic loggerhead sea turtle population, the largest in the world.
"Our study suggests that the cumulative survival from hatchling to maturity, which may take 30 years, combined with present-day climate effects on mature females, has a greater influence on annual nesting population size than does the exclusive impact of survival during the first year of life as hatchlings," biologist Vincent Saba said.
Estimated survival rates for loggerhead sea turtles in the northwest Atlantic are very low, the researchers said; less than 0.2 percent of turtles born in a given year survive to age 30.
The study suggests protection for older juveniles and sub-adults to ensure they reach maturity and breed multiple times is at least as important as protecting hatchlings if the turtles, considered threatened under the U.S. Endangered Species Act, are to survive, they said.