Diamondback terrapins are the only resident turtle within brackish water and estuarine systems. Their range extends from Massachusetts to Texas but, prior to 2005, their existence in the Florida panhandle was undocumented. The Panhandle Terrapin Project was developed to first determine whether terrapins exist in the panhandle (Phase I) and, if so, what is their status (Phase II and III).
The project began at the Marine Science Academy at Washington High School (in Pensacola) in 2005. Between 2005 and 2010 the team was able to verify at least one record in each of the panhandle counties. For Phase II we used what we called the “Mann Method” to determine the relative abundance of terrapins in each area. To do this we needed to conduct assessments of nesting activity in each county. In 2012 the project moved from Washington High School to Florida Sea Grant. At that time, we developed a citizen science program to conduct Phase II of this project. Effort first focused on Escambia and Santa Rosa counties, but in recent years has included Okaloosa County. Florida Sea Grant now partners with the U.S. Geological Survey (based out of Gulf County) to assist with Phase II and lead Phase III, which is estimating populations using mark-recapture methods, as well as satellite tagging to better understand movements and habitat use. The focus of Phase III has been Gulf County, but tagging has occurred in Okaloosa and Escambia counties.
Over the years we have trained 271 volunteers who have conducted thousands of hours of nesting surveys and helped obtain a better picture of the status of diamondback terrapins in the Florida panhandle. Here are the 2023 project results.
Results from 2023
We trained 67 volunteers; 35 (52%) of which participated in at least one nesting survey.
The volunteers conducted 196 surveys logging 212 hours.
During those surveys terrapins (or terrapin sign) were encountered 43 times; a Frequency of Encounter (FOE) of 22%.
Three terrapins were tagged. Two from Okaloosa and one from Escambia. All but two of the nine primary survey beaches saw nesting activity (78%). One new nesting beach was discovered.
Escambia County
Two nesting beaches. 47 surveys. 7 encounters (FOE = 15%).
The Mann Method assumes the sex ratio is 1:1 (male: female) but recent studies suggest the ratio may be as high as 5:1 (male: female). Based on these two rations the number of terrapins estimated to be using these beaches ranged from 4-36.
One terrapin (“Dollie”) was tagged. Fire ants and torpedo grass were reported on some beaches.
Santa RosaCounty
Three nesting beaches. 68 Surveys. 14 encounters (FOE = 21%).
The number of terrapins estimated to be using these beaches ranged from 6-30.
No terrapins were captured, though one was seen nesting. No invasive species were reported from the nesting beaches.
OkaloosaCounty
Four nesting beaches. 67 surveys. 21 encounters (FOE = 31%).
The number of terrapins estimated to be using these beaches ranged from 2-66.
Two terrapins were tagged (“Kennedy” and “Molly”). Phragmites were reported from all beaches.
Walton County
Walton county currently does not have a volunteer coordinator and surveys are not occurring at this time. We are working with an individual who may take the lead on this.
BayCounty
This team is just beginning and currently there are no primary beaches. The team focused on five beaches encountering terrapin nesting activity on one of them. They conducted a total of 14 surveys encountering terrapin tracks on 1 of those (FOE = 7%). The estimated number of terrapins using this beach ranged from 4-12.
Baldwin County Alabama
Due to the proximity of terrapin habitat and nesting beaches at the Alabama/Florida line, and the possibility of terrapins using habitat in both states, a team was developed in Baldwin County Alabama this year. The team began conducting Phase I surveys and encountered one deceased terrapin. No nesting beaches have been identified at this time.
Summary
The results of this year’s surveys suggest that, based on the number of nesting beaches we know of, there are anywhere from 2-66 terrapins utilizing them. Again, two of the primary beaches did not have nesting activity this year. USGS tagging studies will provide better population estimates and a better understanding of how these animals are utilizing these habitats. The current population estimate for Gulf County is a little over 1000 individuals and most are showing relatively small range of habitat utilization, although two individuals in the western panhandle moved from one county to the neighboring one.
Training for volunteers occurs in March of each year. If you are interested in participating, contact Rick O’Connor – roc1@ufl.edu.
Since 2007 Florida Sea Grant has worked with partners, and trained volunteers, to assess the status of the diamondback terrapin in the Florida panhandle. This small emydid turtle is the only one that lives in brackish water and prefers salt marshes. Very little is known about this turtle in this part of the country, and the Panhandle Terrapin Project has the goal of changing that.
Female diamondback terrapin.
Photo: Rick O’Connor
Terrapins have strong site fidelity, meaning they do not roam much, and spend most of their day basking in the sun and feeding on shellfish – marsh snails being a particular favorite. Like many species of turtle, they breed in the spring. Gravid females leave the marsh seeking high dry sandy beaches along the shores of the estuary to lay their eggs. Unlike sea turtles, she prefers to do this on sunny days – the sunnier the better. She typically lays between 7-10 eggs, and they hatch in about two months. The hatchlings spend their early months on shore, hiding under wrack and debris feeding on small invertebrates before heading to the marsh where the cycle begins again.
The project has three objectives each year. One, to survey known (primary) nesting beaches for nesting activity. The number of nests, tracks, and depredated nests can be used to calculate a relative abundance of these animals using those beaches. Two, survey potential (secondary) nesting beaches for any presence of nesting activity. Three, tag terrapins using the old notch method, PIT tags, and a small few with satellite tags. This will help us track terrapin movement and better understand how they use the habitat.
Since the project began, we have been able to verify at least one terrapin in each of the seven panhandle counties being surveyed and have identified nesting beaches in four of those. Relative abundance is rather low when compared to other regions within their range, but those beaches remain active.
The nesting season historically begins in late April and 2023 has been busy early. Seven hatchlings that overwintered in their 2022 nests emerged and were found by volunteers, and others. Two depredated nests were located, and one nesting female was captured and tagged. The volunteers will continue to survey the rest of the spring and much of the summer. Reports of these turtles are important in our assessment. If you believe you have seen a terrapin, contact Rick O’Connor – roc1@ufl.edu – (850) 475-5230 ext.1111. and let us know where.
Female terrapin fixed with a satellite tag for tracking.
Photo: Rick O’ConnorSmall terrapin hatchling released on Santa Rosa Island.
Photo: Rick O’Connor
Since 2005 we have been tracking and monitoring diamondback terrapins in the Florida panhandle. For those of you who are not familiar with the animal, it is a turtle in the family Emydidae. Emydid turtles include what we call “pond turtles” and also include the box turtles. Terrapins differ from the others in that (a) their skin is much lighter, almost white, and (b) they like salt water – more accurately, they like brackish water.
Diamondback terrapin (photo: Molly O’Connor)
The animals range from Massachusetts to Texas and within this there are seven subspecies. Five of these live in Florida, and three only live in Florida. In the Florida panhandle we have two subspecies: the Ornate terrapin (Malaclemys terrapin macrospilota) and the Mississippi terrapin (M.t. pileata). It is believed the that the Mississippi terrapin only exist in Florida within Pensacola Bay – more on that in a moment.
Image provided by FWC
There are literally no peer reviewed publications on terrapins from the Florida panhandle… none. And this was how the Panhandle Terrapin Project began. The first objective for the project was to determine if terrapins even existed here. We began surveying for evidence of terrapins in 2005 using students from Washington High School in Pensacola. The project quickly fell to myself and my wife due to the best time to do terrapin surveys was May and June. And the worst time to work with high school students was May and June. Between 2005 and 2012 we were able to verify at least one terrapin record in each of the panhandle counties. Yes… terrapins exist in the Florida panhandle.
The second objective was to assess their population status. To do this we used what I call the Mann-Method. Tom Mann, Mississippi Department of Wildlife, had developed a method of using nesting surveys to estimate relative abundance of terrapins within a population. Terrapins tend to have strong site fidelity – they are “home bodies” – and do not move from marsh to marsh. If you can find their marsh, you can find their nesting beaches. If you can find their nesting beaches you can use the Mann-Method to assess their relative abundance.
Tracks of a diamondback terrapin.
Photo: Terry Taylor
There are a couple of assumptions with the Mann-Method. (1) You are assuming every female in the population nest every year – we are not sure that is true. (2) You are assuming that each female will lay more than one clutch of eggs each season – we do believe this is true. (3) You are assuming that each female will not lay more than one clutch in a 16-day period – we are not sure this is true. (4) You know where all of the nesting beaches are – we are not sure we do. (5) The sex ratio of male to female is 1:1 – we are sure that is not the case. One study suggested that in the panhandle the ratio may be 1:3 in favor of males, another suggested 1:5 in favor of males.
Based off this model, and its assumptions, during a 16-day period of the nesting season, each track/nest would be an individual female. Using 1:1, 1:3, and 1:5 as your sex ratio you can get an estimate of relative abundance.
Another method for estimating relative abundance is counting the number of heads in a 30-minute period. It is understood that if I see different heads during periods of the survey, I may be seeing the same head, but the argument is that if I typically see 10-15 heads during a 30-minute and over time that becomes 15-20, or 20-25, the relative abundance of terrapins is increasing – and visa versa.
A terrapin swimming near but not entering a modified crab trap.
Photo: Molly O’Connor
And we now have a third and fourth objective. A third objective is to capture animals to place tags on them. Doing this can give us a better idea of how these terrapins are using the habitats in the panhandle, how far they may travel and how they are getting there. The fourth objective is to obtain tissue samples for genetic analysis. The purpose of this is to determine whether the populations in Pensacola Bay are Mississippi terrapins, Ornate terrapins, or hybrids of the two.
Since 2015 this work is now being conducted by trained volunteer citizen scientists – people like you – and we do the trainings in March if interested.
So… how did things go in 2022?
In 2022 we trained 47 volunteers to be survey beaches. 25 (53%) participated in at least one survey.
173 surveys were conducted between April 2 and July 31 at 14 nesting beaches between Escambia and Bay counties. Encounters with terrapins, or terrapin sign, occurred during 43 of the 173 surveys (25%) and three terrapins were captured for tissue and tagging.
Escambia County
Number of Surveys
Dates
Number of Surveys / Day
29
Apr 3 – Jul 31
0.2
Number of Encounters
Frequency of Encounters
Heads / 30-minutes
Estimated Relative Abundance
4
.18
No surveys conducted
4-12
Santa Rosa County
Number of Surveys
Dates
Number of Surveys / Day
58
Apr 4 – Jul 5
0.6
Number of Encounters
Frequency of Encounters
Heads / 30-minutes
Estimated Relative Abundance
15
.26
N=2, 0-49, X = 24
30-90
Okaloosa County
Number of Surveys
Dates
Number of Surveys / Day
43
Apr 18 – Jul 15
0.5
Number of Encounters
Frequency of Encounters
Heads / 30-minutes
Estimated Relative Abundance
25
.58
N=17, 0-32, X = 11
30-90
No surveys were conducted in Walton County
Bay County
Number of Surveys
Dates
Number of Surveys / Day
43
Apr 2 – Jun 30
0.5
Number of Encounters
Frequency of Encounters
Heads / 30-minutes
Estimated Relative Abundance
0
.00
No surveys conducted
0
Summary of 2022 Terrapin Season
Surveys of nesting beaches occurred in four of the five counties in the western panhandle.
Terrapins were encountered in each of these cand captured in two of them.
The relative abundance ranged between 0 (Bay County) to between 30-90 individuals (Santa Rosa and Okaloosa counties) and was about 64-192 animals for the entire western panhandle (depending on the sex ratio you use).
We are sure that we have not found all of the nesting beaches in this region and will continue to look for more.
We are awaiting results from the tissue sampling to determine whether we have a distinct population of Mississippi terrapins in Pensacola Bay, but more samples will be needed.
We need to place satellite tags on some females to get a better idea of how they travel through the system.
And our relative abundance numbers suggest that populations in the Florida panhandle are relatively small compared to others within the terrapin range.
More needs to be done and we will continue to survey each spring. If you are interested in becoming a member of the Panhandle Terrapin Project, contact me (Rick O’Connor) at roc1@ufl.edu.
One of the programs I focus on as a Sea Grant Extension Agent in Escambia County is restoring the health of our estuary. One of the projects in that program is increasing the encounters with estuarine animals that were once common. Currently I am focused on horseshoe crabs, diamondback terrapins, and bay scallops. Horseshoe crabs and bay scallops were more common here 50 years ago. We are not sure how common diamondback terrapins were. We know they were once very common near Dauphin Island and are often found in the Big Bend area, but along the emerald coast we are not sure. That said, we would like to see all of them encountered more often.
Horseshoe crabs breeding on the beach. Photo: Florida Sea Grant
There are a variety of reasons why species decline in numbers, but habitat loss is one of the most common. Water quality declined significantly 50 years ago and certainly played a role in the decline of suitable habitat. The loss of seagrass certainly played a role in the decline of bay scallops, but overharvesting was an issue as well. In the Big Bend region to our east, horseshoe crabs are also common in seagrass beds and the decline of that habitat locally may have played a role in the decline of that animal in our bay system.
Salt marshes are what terrapins prefer. We have lost a lot of marsh due to coastal development. Unfortunately, marshes often exist where we would like houses, marinas, and restaurants. If the decline of these creatures in our bay is a sign of the declining health of the system, their return could be a sign that things are getting better.
Seagrass beds have declined over the last half century. Photo: Rick O’Connor
Salt marshes have declined due to impacts from coastal development. Photo: Molly O’Connor
For over 10 years we have been conducting citizen science monitoring programs to monitor the frequency of encounters of these creatures. All three are here but the increase in encounters has been slow. An interesting note was the fact that many locals had not heard of two of them. Very few knew what a horseshoe crab was when I began this project and even fewer had heard of a terrapin. Scallops are well known from the frequent trips locals make to the Big Bend area to harvest them (the only place in the state where it is legal to do so), but many of those were not aware that they were once harvested here.
I am encouraged when locals send me photos of either horseshoe crabs or their molts. It gives me hope that the animal is on the increase. Our citizen science project focuses on locating their nesting beaches, which we have not found yet, but it is still encouraging.
Volunteers surveying terrapin nesting beaches do find the turtles and most often sign that they have been nesting. The 2022 nesting season was particularly busy and, again, a good sign.
It is now time to do our annual Scallop Search. Each year we solicit volunteers to survey a search grid within either Big Lagoon or Santa Rosa Sound. Over the years the results of these surveys have not been as positive as the other two, but we do find them, and we will continue to search. If you are interested in participating in this year’s search, we will be conducting them during the last week of July. You can contact me at the Escambia County Extension Office (850-475-5230 ext.1111) or email roc1@ufl.edu or Chris Verlinde at the Santa Rosa County Extension Office (850-623-3868) or email chrismv@ufl.edu and we can set you up.
Bay scallops need turtle grass to survive. Photo: UF IFAS
Volunteers participating in the Great Scallop Search. Photo: Molly O’Connor
Final note…
Each June I camp out west somewhere and each year I look for those hard-to-find animals. After 10 years of looking for a mountain lion, I saw one this year. Finding these creatures can happen. Let’s hope encounters with all three become more common in our bay.
As the Sea Grant Extension Agent in Escambia County, one of my program areas is to help restore a healthy estuary. To do this we focus on educating the public how to improve water quality, restore habitat, and manage invasive species, but we also focus on how to monitor fish and wildlife. The fish and wildlife I focus on are those that were once common in the bay and are trying to make a comeback – such as scallops and horseshoe crabs. But there is another estuarine creature we are interested in that does not fall into the classic “bring them back” model and that is the estuarine turtle known as the diamondback terrapin.
The diamondback terrapin. Photo: Molly O’Connor
Unlike scallops and horseshoe crabs, this is not an animal that people remember as a kid. In fact, very few Floridians in the panhandle have ever heard of it. Some older distribution maps of their range show that they exist from Cape Cod MA to Brownsville TX, but with a gap in the Florida panhandle. That was because there was no scientific literature of the animal’s existence here. And that was when the Panhandle Terrapin Project began – to confirm whether or not terrapins existed here.
In 2005, working with students at Washington High School in Pensacola, we began our search by placing “Wanted Posters” at boat ramps in Escambia and Santa Rosa counties near good terrapin habitat, which is salt marsh. We began to get calls almost right away, but for a variety of other turtle species. Folks were calling us with photos of box turtles, yellow-bellied sliders, and cooters. It showed there was interest in the project but was evident they were not familiar with the terrapin.
Around 80% of the terrapin nests are depredated by raccoons, or some other predator. Photo: Bob Blais
Volunteers log the number of female tracks they see on their beaches. Photo: Cindy Marvel
I interviewed several ole gill netters to see if they remember ever capturing them – same response, “I never heard of those”. I did show one gill netter a photo and he responded – “you know, I think we did catch a couple of these”. But no confirmation of their existence here. It was time to begin searching ourselves.
The team began to survey good terrapin habitat and walking potential nesting beaches looking for any evidence. We did not find it. Then one day in 2007 a gentleman working on a construction site responded to one of our “Wanted Posters”. He said he had seen one of our terrapins. After all of the calls that led to other species, I was not so sure – but he convinced me it might be. So, we checked it out. The sign was placed in good habitat and there were potential nesting beaches nearby. We searched… and we found. What we found were nests that had been depredated by raccoons. There were empty eggshells laying around and two dead hatchlings. There were also tracks in the sand. Confirmation… there were terrapins here!
It was now time to take the show on the road and see if terrapins exist in other counties along the panhandle. My wife and I would take part of our summer vacations and camp along the coast searching. We found at least one record of a terrapin in each of the counties between the Alabama state line and Apalachicola River. All of this was presented to the Florida Diamondback Terrapin Working Group of which there are members from the Florida Fish and Wildlife Conservation Commission. Word was out.
Terrapins prefer sandy beaches and lay their eggs during daylight hours. Photo: Molly O’Connor
A terrapin hatchling. Photo: Molly O’Connor
The next step was to assess their status. How many are here and how are those populations doing?
We did this by following a method developed by Tom Mann with the Mississippi Department of Wildlife. Tom was monitoring terrapins in that state and the subspecies he worked with, the Mississippi Terrapin (Malaclemys terrapin pileata) was the one that was thought to be in Pensacola Bay. So, it was Tom’s method we decided to follow. This includes walking nesting beaches and logging individual tracks and depredated nests in 16-day cycles. Tom’s model assumed that all mature females in the population nest each season and that they do not lay more than one clutch in a 16-day period. The idea is that each track and nest represented one female, and assuming the sex ratio of male to female is 1:1, doubling the number of tracks and depredated nests found in that period would give an idea of how many adult males and females are in this group. Seemed easy enough so these surveys became part of our project.
Another method learned by attending conferences was a 30-minute head count. If you can find the lagoons where the terrapins actually live you can sit and count the number of heads you see in a 30-minute period. It is true that 23 heads does not mean there are 23 terrapins, but the relative abundance can be monitored. If you typically see 20-23 heads and over time that decreases to 11-15, then the relative abundance is declining. It is a method that citizen science volunteers can do and so was included in the project.
Modified crab traps is one method used to capture adults. Photo: Molly O’Connor
A diamondback terrapin being measured and marked before release. Photo: Rick O’Connor
We also wanted to try and capture individuals to mark and tag. Mark recapture is a method used to estimate populations but capturing terrapins has been historically difficult to do. Several methods have been used by members of the Working Group and we have tried them as well. We have captured terrapins, but very few.
In 2018 the Team partnered with the U.S. Geological Survey to increase the robustness of the project. The Florida Fish and Wildlife Conservation Commission became interested in tissue samples from captured animal to study the genetics of the terrapins in this area. Since 2015 we have trained 228 individuals to conduct surveys, and some have been with me that entire time. Many of them have spent countless hours helping assess the status of this animal in our bays. Many days they see nothing. Others a few tracks or depredated nests. Some locations have good luck with head counts, but many of them finding nothing.
The Mississippi terrapin found in Pensacola Bay is darker in color than the Ornate terrapin found in other bays of the panhandle. Photo: Rick O’Connor
This terrapin has the coloration of the Ornate terrapin but was found much further west than the literature suggest it lives. Photo: Rick O’Connor
I keep track of “Frequency of Occurrence” (FOO) – the number of surveys where some sort of terrapin encounter happens. This encounter can be as simple as a track in the sand, but they had SOME encounter. It is my hope that over time encounters with them will increase, just as I hope it does with scallops and horseshoe crabs. Since 2007 the FOO has ranged from 12-86% of the surveys conducted, with an average of about 25%. The best year was 2011 (86%), just after the Deepwater Horizon spill. There was a steady increase in FOO from 2007 to 2012 when it took a significant drop. However, this is not because the relative abundance of terrapins suddenly dropped. 2012 was the year I moved from the marine science program at Washington High School to Florida Sea Grant Extension. There were all new volunteers and the learning curve started over. They were not as good at detecting them as the previous group. But that is changing. 2022 is looking to be a busy year for the team.
So far this year we have seen terrapin activity on almost every nesting beach between here and Apalachicola. One site had 49 heads in a 30-minute head count! There have been several active nests, numerous tracks, and plenty of depredated nests. In addition, we have found one dead hatchling and captured two adults. Tissue from these have been collected for the genetic study. But the strangest story this year… a security guard has told us of terrapin hatchlings that have been dropped on their guard shack by birds. Sea birds are known to do this to try and crack open shells of mollusk so they can feed on them. I have never heard of this with terrapins, not here or anywhere.
A dedicated volunteer is rewarded with a capture. Photo: Rick O’Connor
It seems it is going to be a terrific year for the terrapin project this year. It is exciting for our volunteers to have so many encounters and nice to know that the public is becoming more familiar with this animal. I cannot say whether the population is increasing or not but our knowledge, understanding, and encounters are.
