Connecting the Spots: Field Research on New Jersey’s Spotted Turtles

A small cluster of gold glints below the water’s surface, moving carefully and purposefully through the matrix of underwater habitat. It is the shell of a Spotted Turtle (Clemmys guttata), a small freshwater dwelling turtle found across our state of New Jersey. I wasn’t kidding when I said Spotted Turtles are small, typically reaching around 3.5 to 4.75 inches at maturity! They inhabit a wide range of wetland habitats; including vernal pools that dry up in the summer, bogs, flooded fields, and even ditches. Their diet consists of mainly smaller aquatic animals, from amphibians and their eggs to invertebrates like worms and even aquatic plant material at times. The nature of their more generalist diet may make them opportunists, utilizing locally abundant food resources at different times of the year. An example of this could be wood frogs and their eggs, which are hyper-abundant in vernal pools in the early spring. The activity window for Spotted Turtles begins around this time and they may key in on Wood Frogs as a food source before moving on to the next abundant prey item. Spotted Turtles are sexually dimorphic, meaning you can visually separate adult males and females. Females have colorful lower jaws, flat plastrons, and shorter tails whereas males have drabber jaws, con-caved plastrons, and longer thicker tails.

A species of special conservation concern in the state of New Jersey, Spotted Turtle populations have been estimated to have decreased 50% range-wide per the International Union for Conservation of Nature. Despite their ability to be very abundant in small areas they are showing signs of a declining population. This is due to a multitude of factors dating back to the colonization of North America. Primarily loss and degradation of wetlands have impacted Spotted Turtles, where this species resides for most of its life history. Other factors leading to their decline include habitat fragmentation which has separated populations of turtles that used to be interconnected and poaching for the aquarium industry removing turtles that were supporting these populations. Because of this decline, the Eastern Spotted Turtle Working Group was formed to conduct a population wide assessment and create a protocol for Spotted Turtle monitoring projects across the species’ range.

Conserve Wildlife Foundation of New Jersey (CWF) is involved in monitoring projects to assess Spotted Turtle populations in several under-sampled areas of the state. Our primary project is understanding Spotted Turtle populations in the southern Delaware River Watershed, in the pinelands of Burlington County as well as the lowlands of Salem County. Funding for this project is provided by a grant received from the National Fish and Wildlife Foundation – Delaware Watershed Conservation Fund. Another of our projects is in partnership with the United States Fish and Wildlife Service (USFWS) monitoring populations at Joint Base McGuire-Dix-Lakehurst (JB MDL). These projects involve using the developed monitoring protocol to gain a better understanding of Spotted Turtle distribution and populations at our targeted study areas.

The project has been quite successful in capturing turtles, having caught and marked well over 100 unique turtles amongst our various sites! After catching a turtle several pieces of information are taken including shell measurements, weight, sex, shell wear, and more. This data gives us insight into the status of a population. For example, more captures of juvenile turtles may indicate that the population is still reproducing successfully whereas a lot of adult captures may indicate a population that isn’t having as much reproductive success.

Spotted Turtles were not the only wildlife we caught. A huge variety of by-catch kept our daily checks interesting on days and at sites that didn’t have many Spotted Turtles. Painted and Musk Turtles were by far the most numerous by-catch. Red-bellied Cooter, Mud Turtle, and Snapping Turtle were also turtles that we encountered, with Snapping Turtles giving us some challenges to handle given their biting nature. Besides turtles, we captured Northern Water Snake, larger frogs like Bull and Green Frog, crayfish, and a plethora of fish species. One fish species of note was the Mud Sunfish, another species of special conservation concern to the state that was found on several Joint Base McGuire-Dix-Lakehurst wetlands and ponds. These bycatch captures were particularly insightful for the natural resource managers at Joint Base to improve their understanding of other wildlife in the wetland areas on the base.

For all our turtle success this season it was not without setbacks. Drought conditions had carried over from last year and were very apparent at many of the vernal pool sites we surveyed, with water levels seemingly lower than typical for spring. One of the vernal pool sites scouted had no water in it. Thankfully, rain events helped replenish and maintain water levels in some of our pools to keep sites viable for turtle activity and monitoring! Another developing story is that our CWF team aided in catching a turtle poacher in the act after finding a suspicious trap at one of our sites. A small win for the conservation of these turtles, but poaching is still a very real threat. If you see any suspicious activity don’t hesitate to reach out to our state’s conservation law enforcement, we are the eyes and ears for them out there.

As our assessment comes to an end we have lots of data to pour over, but we are looking forward to gathering insights into our state populations of this incredible turtle species and informing conservation of a species in decline. Thank you for your vital support of CWF to make projects like this possible and for giving support and attention to a species that needs our help.