#SeaTurtleTalks: Trends in Florida sea turtle size at maturity

Located on the east coast of Florida, USA, the Archie Carr National Wildlife Refuge hosts tens of thousands of sea turtle nests every year. It’s an ideal site to study population trends.

#TurtleTuesday 🌊🐢
The #UCFTurtleLab has been monitoring sea turtles in 21 km of the #ArchieCarrNWR since the early 1980s.

Loggerhead nest counts have been fairly consistent over time, while green turtle nests have increased.
We use calipers to measure nesting sea turtles at night.

Our crew noticed that small turtles seemed to be more common, so we decided to look at the data.

#longtermdata #fieldwork #UCFTurtleLab
Average size decreased in both species, 🟩 green turtles had the larger decrease

The smallest 2.5% of turtles decreased in both species, 🟫 loggerheads had the larger decrease (75.9-79.8 cm ➡️ 68.1-75.8 cm)

For more analyses, check out our paper
Why does this matter?

Smaller turtles tend to lay fewer eggs, so there’s a concern that hatchling production may go down. 🥚🥚➡️🥚

For in-water studies that estimate maturity based on individuals’ size, metrics may need to be adjusted.
What could be happening?

Juvenile growth rates may have slowed, leading to ⬇️ size at maturity.

Maybe there are more first-time nesters. For species that can mature at a range of sizes, this may point to a shift in size at maturity. Or a first wave of new recruits.
What could be happening?

Contributions from different foraging sites may have changed. #ArchieCarrNWR loggerheads foraging at the MAB tend to be largest. But all greens tracked so far forage in the FL Keys or The Bahamas.

What are other possible causes of the size trends?

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