UF/IFAS scientists count record number of threatened crocodile hatchlings in Everglades

September 23, 2014

GAINESVILLE, Fla. --- A record number of American crocodile hatchlings have been counted in the Everglades National Park this summer -- a positive development for the threatened species, University of Florida scientists say.

The American crocodile was listed as a federally endangered species in 1975, and while reclassified as threatened in 2007, the species still faces problems from habitat loss and environmental changes.

Frank Mazzotti, a UF Institute of Food and Agricultural Sciences professor, has monitored the South Florida crocodile population since 1978.

This summer, he and his team of researchers that included Michiko Squires, Seth Farris, Rafael Crespo and research coordinator Jeff Beauchamp, caught, marked and released 962 hatchlings within the confines of the national park, a big jump from last summer’s 554.

The total American crocodile hatchlings in Florida this year came to 1,447, over last year’s 1,006, including those found in the park, Crocodile Lake National Wildlife Refuge in Key Largo and Florida Power and Light Company Turkey Point power plant site.

Mazzotti cautioned that the numbers aren’t proof that ecosystem restoration efforts are working, but he believes the correlation suggests they are.

The coastline of Everglades National Park, prime habitat for the American crocodile, was largely untouched by humans until the early 20th century. But a network of canals was dug to drain water from the marshes to make the area suitable for agriculture and residential development, which triggered environmental changes, such as increased inland salinity.

And crocodiles, extremely sensitive to environmental changes such as salinity and water levels, suffered. High salinities stress hatchling crocodiles directly, and high salinity and high water levels limit availability of prey.

Restoration plans to plug coastal canals in the national park aim to prevent salt water intrusion and fresh water losses to tide.

“What we hope is the lesson is that ecosystem restoration efforts can work. If the signal is correct here, we can monitor that improvement by looking at ecological responses – and crocodiles make good indicators,” Mazzotti said.

Crocodiles, as a species, are some 200 million years old. They can live for decades, can survive long periods without food and can eat almost anything. They have complex social relationships and are known to be quick learners.