Let’s begin by stating what a diamondback terrapin is. I have found many Floridians are not familiar with the animal. It is a turtle. A turtle in the family Emydidae which includes the pond turtles, such as cooters and sliders. The big difference between terrapins and the other emydid turtles is their preference for salt water. They are not marine turtles but rather estuarine – they like brackish water.
The diamond in the marsh. The diamondback terrapin. Photo: Molly O’Connor
Their haunt are the salt marshes and mangroves of the state. Their range extends from Massachusetts down the east coast and covering all of the Gulf of Mexico over to Brownsville Texas. There are seven subspecies of the animal within that range. Five of those live in Florida and three only live in Florida. They are more abundant, and well known, in the Chesapeake Bay area where they are the mascot of the University of Maryland. In Florida they seem to be more secretive and hidden. Encounters with them are rare and there has been concern about their status for years. Though researchers are not 100% sure on their population size, it was felt that more conservation measures were needed.
Ten years ago, the issue with all turtles in the state was the illegal harvest for the food trade. All sorts of species were being captured and sent to markets overseas. The Florida Fish and Wildlife Conservation Commission (FWC) stepped in and set possession quotas on many species of Florida turtles. For terrapins, the number was two. For some, like the Suwannee Cooter, there was a no possession rule.
Drowned terrapins in a derelict crab trap in the Florida panhandle. (photo: Molly O’Connor)
There has also been concern with incidental capture of terrapins in crab traps. These turtles have been known to swim into the traps and drown. In the Chesapeake Bay area, they have found as many as 40 dead turtles in one trap. Not only is this bad for the turtles, but it is also bad for the crab fisherman because high numbers of dead turtles in the trap means no crabs. Studies began to develop some sort of excluder device that would keep terrapins out, but allow crabs in. Dr. Roger Wood developed a rectangle shaped wire excluder now called a By-Catch Reduction Device (BRD) that reduced the terrapin capture by 80-90% but had no significant effect on the crab catch. That was what they were looking for. This BRD has been required on crab traps up there for years.
What about Florida?
Studies using the BRD were also conducted here with the same results, but the BRD was not required. Incidental capture in crab traps does occur here but not to the extent it was happening in the Chesapeake and FWC wanted to hold off for more science before enacting the rule. BRDs were available for those who wanted them, but not required. This past December (2021) that changed.
This orange plastic rectangle is a Bycatch Reduction Device (BRD) used to keep terrapins out of crab traps – but not crabs. Photo: Rick O’Connor
In recent years there has been another issue with harvesting terrapins for the pet trade. With this, and other conservation concerns for this turtle, FWC developed a new rule for terrapins at their December 2021 meeting.
The possession limit for terrapins has dropped from 2 to 0 – there is a no-take rule for this animal beginning March 1, 2022. Collection for scientific research will still be allowed with a valid collecting permit from the FWC. Those who currently have two or less terrapins in their possession as pets may keep them but must obtain a no cost personal possession permit to do so by May 31, 2022. Those who have terrapins within an education center may keep them but must obtain a no cost exhibit permit by May 31, 2022.
Recreational crab traps will require the BRD device by March 1, 2023. You have a year. Those in the Pensacola area can contact me for these. I have a case of them I am willing to provide to the public.
Again, studies have shown that these BRDs do not significantly impact the crab catch. Crabs can turn sideways and still enter the traps. But reducing incidental capture of terrapins will hopefully increase their numbers in our state. For information on how to obtain the needed permits visit FWC.
We have a lot of really cool and interesting creatures that live in our bay, but one many may not know about is a small turtle known as a diamondback terrapin. Terrapins are usually associated with the Chesapeake Bay area, but actually they are found along the entire eastern and Gulf coast of the United States. It is the only resident turtle of brackish-estuarine environments, and they are really cool looking.
The diamond in the marsh. The diamondback terrapin. Photo: Molly O’Connor
Terrapins are usually between five and 10 inches in length (this is the shell measurement) and have a grayish-white colored skin, as opposed to the dark green-black found on most small riverine turtles in Florida. The scutes (scales) of the shell are slightly raised and ridged to look like diamonds (hence their name). They are not migratory like sea turtles, but rather spend their entire lives in the marshes near where they were born. They meander around the shorelines and creeks of these habitats, sometimes venturing out into the seagrass beds, searching for shellfish – their favorite prey. Females do come up on beaches to lay their eggs but unlike sea turtles, they prefer to do this during daylight hours and usually close to high tide.
Most folks living here along the Gulf coast have not heard of this turtle, let alone seen one. They are very cryptic and difficult to find. Unlike sea turtles, we usually do not give them a second thought. However, they are one of the top predators in the marsh ecosystem and control plant grazing snails and small crabs. During the 19th century they were prized for their meat in the Chesapeake area. As commonly happens, we over harvested the animal and their numbers declined. As numbers declined the price went up and the popularity of the dish went down. There was an attempt to raise the turtles on farms here in the south for markets up north. One such farm was found at the lower end of Mobile Bay.
Early 20th century still found terrapin on some menus, but the popularity began to wane, and the farms slowly closed. Afterwards, the population terrapins began to rebound – that was until the development of the wire meshed crab trap. Developed for the commercial and recreational blue crab fishery, terrapins made a habitat of swimming into these traps, where they would drown. In the Chesapeake Bay area, the problem was so bad that excluder devices were developed and required on all crab traps. They are not required here in Florida, where the issue is not as bad, but we do have these excluders at the extension office if any crabber has been plagued with capturing terrapins. Studies conducted in New Jersey and Florida found these excluder devices were effective at keeping terrapins out of crab traps but did not affect the crab catch itself. Crabs can turn sideways and still enter the traps.
This orange plastic rectangle is a Bycatch Reduction Device (BRD) used to keep terrapins out of crab traps – but not crabs. Photo: Rick O’Connor
Another 20th century issue has been nesting predation by raccoons. As we began to build roads and bridges to isolated marsh islands in our bays, we unknowingly provided a highway for these predators to reach the islands as well. On some islands, raccoons depredated 90% of the terrapin nests. Today, these turtles are protected in every state they inhabit except Florida. Though there is currently no protection for the terrapin itself in our state, they do fall under the general protection for all riverine turtles; you may only possess two at any time and may not possess their eggs.
Some scientists have discussed identifying terrapins as a sentinel species for the health of estuaries. Not having terrapin in the bay does not necessarily mean the bay is unhealthy, but the decline of this turtle (or the blue crab) could increase the population of smaller plant grazing invertebrates they eat throwing off the balance within the system.
Sea Grant trains local volunteers to survey for these creatures within our bay area. Trainings usually take place in April and surveys are conducted during May and June. This year we will be training volunteers in the Perdido area on April 10 at the Southwest Branch of the Pensacola Library on Gulf Beach Highway. That training will begin at 10:00 AM. For Pensacola Beach the training will be on April 15 at the Navarre Beach Sea Turtle Conservation Center on Navarre Beach. That training will begin at 9:00 AM. A third training will take place on April 22 at the Port St. Joe Sea Turtle Center in Port St. Joe. For more information on diamondback terrapins contact me at the Escambia County Extension Office – (850) 475-5230 ext. 111.
It is hard to say one turtle is more beautiful than another but this is one beautiful turtle! The diamondback terrapin is the only brackish water turtle in the United States. These turtles can be easily distinguished from other species by their light colored skin with dark spots, and their choice of habitat – salt marshes.
Ornate Diamondback Terrapin (photo: Dr. John Himes)
Terrapins inhabit creeks within marshes close to where they were born and rarely range from their natal home. They require dry ground for nesting. Terrapins spend their time basking in lagoons near the surface or on open mudflats at low tide. They feed primarily on shellfish, preferring snails and bivalves, but will also feed on small crabs, shrimp, worms, fish, and occasionally vegetation.
The females are larger than the males and have shorter tails. Mature females typically lay 6 to 10 eggs and will nest more than once in the same year. Nesting begins in late April in our part of the country and females laying multiple clutches will do so every 16 days. The sex of the offspring is determined by the nest temperature (warmer than 29˚C = females) so generally the eggs in the upper part of the nest are female. Unlike sea turtles, female terrapins approach the nesting beach at high tide during daylight hours. Most of the nests we find in Santa Rosa County are near salt bush (Baccharis sp.) but we have found them in open areas or near debris like driftwood. They also differ from sea turtles in that young head away from open water preferring the plants of the marsh. The heaviest predation is on the eggs and young. The dominant nest raider is the raccoon. Hatchlings are preyed upon by raccoons, otters, skunks, crows, and sea gulls; adults have few predators.
Terrapin populations have declined over the last 150 years. In the late 19th century it became very popular to eat them and the demand for the animal became an economic dynamo for many coastal fishermen. Terrapin researchers from the University of Alabama at Birmingham found a newspaper article from that time period that discussed a terrapin farm in Mobile County that had 25,000 terrapins; suggesting they were once very common. With the increase in the popularity for food their numbers decreased, this caused an increase in price and a decline in their popularity. The introduction of the crab trap in the 20th century became problematic for them. Terrapins swim into traps and can not reach the surface to breathe. In some states a “by-catch reduction device” or BRD is required on crab traps. Studies of these in New Jersey and Florida showed they have no significant impact on the crab catch but do reduce the number of terrapins captured. BRDs are not currently required in Florida as commercial traps are actively fished and bycatch removed when crabs are harvested. “Derelict” crab traps are those that are not actively being fished, killing all sorts of aquatic life. Derelict crab trap removal events which removes this potential hazard to turtles and to blue crabs as well.
We have been conducting a monitoring program assessing the status of Terrapins in the Panhandle since 2006 and have found at least one in every coastal county between Alabama and the Apalachicola River. We have identified five nesting beaches and believe that one population has between 25-50 individuals within it (likely much lower numbers than historically found). The marsh turtle status is certainly of concern for many biologists.
To learn more about terrapins and the crab trap removal program visit the following websites or call your local extension office. For more information on obtaining a bycatch reduction device (BRD) for your recreational crab traps contact Rick O’Connor, 850-475-5230.
Terrapins in a derelict crab trap (photo: Molly O’Connor)
