Stay in the know about wildlife, water quality, and ecosystems on Sanibel and Captiva Islands and in Southwest Florida

Recapture Study Provides Long-Term Insight

May 20, 2020

SCCF has several long-term wildlife projects where species are either marked with microchips (pit-tags), the notching of the carapace, clipping of scales, color-coded banding around the legs, photographing of unique characteristics or a combination of these techniques to identify individuals of a population. 

By marking individuals, our scientists can determine population estimates, seasonal activities, ontogenetic shifts or changes in appearance over time, and longevity. 

The diamondback terrapin (Malaclemys terrapin) is a brackish water turtle species that primarily lives in mangrove waterways in our area.  SCCF has been studying terrapins since 2013 as part of the SCCF Diamondback Terrapin Project and many habitat and life history notes have been documented. 

For example, a female terrapin (#40) was captured for the first time on May 7, 2013. At that time, she was an immature female with a carapace length (CL) of 112 mm (4.4 in).  She was also recaptured in 2014 and 2015 but had not been seen in five years. 

Coincidentally, this terrapin was just recaptured on May 7, 2020, which is exactly seven years to the day of her initial capture at the same location.  She is now a mature female with a CL of 169 mm (6.65 in) that likely averages 2-3 clutches of egg per year with an average clutch size of 3-6 eggs. The terrapins in our study are marked with scute notching, microchips, and photography (carapace, plastron, and head pattern). 


 A high percentage of the terrapins in our project show high site fidelity or philopatry, which means that they tend to stay throughout the year or return to a certain area seasonally. Others appear to be transient and arrive only at the study site as part of breeding aggregations and then leave. 

On an annual basis, we sample these creeks where terrapins gather to breed and continue to document high recapture rates and also a mostly consistent quantity of transient adult terrapins and young recruits that are now large enough to enter the population in mangrove creeks. Hatchling and juvenile terrapins under 82 mm (3.2 in) live in a different habitat.

To learn more about our terrapin study click here

If you see a terrapin in Southwest Florida, please try to take a picture and notify us via email



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