The Diamondback terrapin is more than just a school mascot or the Maryland state reptile — it is the symbol for healthy and productive coastal bays. This amazing turtle is comfortable on both land and in the water, calling our marshes, beaches and bays home. But while we can see terrapins almost anywhere on the Eastern Shore, we still have much to learn about this elusive turtle.
Terrapins are perfectly suited for the coastal bays ecosystem. Not only do they have long nails that they can use for digging or climbing on land, they also have webbed feet that allow them to swim and dive for food. Because terrapins spend most of their time in the water hunting for food, they have evolved the ability to hold their breath for a long time because they don’t possess gills; a mature terrapin can hold its breath anywhere from 45 minutes to five hours.
Female and male terrapins are sexually dimorphic, meaning that males and females look different from each other at maturity. Males will only grow to around 6 inches and weigh around 1/2 to 1 pound at maturity, while females can be twice as big, growing to around 12 inches and 1½ to 2 pounds.
Reproduction for diamondback terrapins occurs from May through July, depending on temperature. Females will crawl onto sandy beaches or dunes, dig a hole roughly 6 inches deep, and then lay her clutch of eggs, which are usually 8-12 eggs per clutch. After 60-120 days, the eggs will hatch, forcing the terrapin hatchlings to navigate their way to water in order to feed.
Mature female terrapins can lay around 3 clutches per year — about 36 eggs total per season. Unfortunately, due to predation and storm events, most terrapin eggs and hatchlings do not make it to maturity; only 1-3 percent of eggs make it to hatchlings and a similarly low percentage of hatchlings survive to sexual maturity.
One of the biggest problems facing terrapin populations in our coastal bays is crab pots — especially “ghost pots,” which are crab pots that are no longer attached to a marker or float so they will never get hauled in and collected. Crab pots are dangerous for terrapins, especially the smaller males and immature terrapins, because they are lured into the pots by the crab bait, get stuck and then drown in the traps because they need to surface in order to breathe.
The best way to solve this problem is to equip all crab pots with Turtle Excluder Devices (TED). TEDs are orange plastic and wire rectangles that are large enough to let crabs through but small enough to block terrapins from getting into the pots and getting stuck. For them to work they need to be about 1 3/4 inches wide and 4 3/4inches long. Some crab pots sold today already have TEDs installed; however, if you buy a pot without one, they are cheap to buy or build and easy to install with directions on the Maryland Department of Natural Resources website.
The Maryland Coastal Bays Program is partnering with the Terrapin Work Group to conduct the second annual Diamondback Terrapin Blitz from May 29 through June 1. The blitz consists of groups of trained volunteers on boats and on the shorelines throughout our coastal bays searching for terrapins in the water and on land. Volunteers will collect data on the number of diamondbacks spotted, where and when they were spotted and other vital information so researchers can gain a better understanding of this evasive creature.
Please contact us if you would like to volunteer for this event.