Demography of an Isolated Spotted Turtle Population in Massachusetts 

Presenter: Audrey Jane Methot

Faculty Sponsor: Allison Roy

School: UMass Amherst

Research Area: Environmental Science and Sustainability

Session: Poster Session 5, 3:15 PM - 4:00 PM, Auditorium, A42

ABSTRACT

The Spotted Turtle (Clemmys guttata) is a small freshwater turtle species native to the midwestern and eastern United States, as well as southeastern Canada. In the last 30 years they have experienced an estimated decline of 50% across their range, with remaining fragmented Spotted Turtle populations often containing <100 individuals. Given this status, data on abundance, age structure, and other demographic characteristics for local populations is helpful for informing management decisions. We initiated a demographic study of a Spotted Turtle population in Middlesex County, Massachusetts, using mark-recapture. Turtles were caught via traps and uniquely marked by notching their marginal scutes. Three, 12-day trapping sessions were held between April and August 2025, where 5 traps in one wetland were checked every 24 h and rebaited every 48 h. In traps, we captured a total of 45 Spotted Turtles, of which 33 were unique individuals. With a closed population model, our findings estimate a population size of 61.4 (±17.2 SE) individuals. We found a sex ratio (male: female) of 1:1.2, suggesting no significant skew (p=0.746). Of the turtles captured, 6.1% were 0-6 years of age, 78.9% were ages 7-13 (average age range of maturation), and 15.2% were age 14 and above. Given the current estimate for spotted turtle longevity is 65 to 110 years, the age structure observed suggests this population has had successful recruitment in the last decade. Comparing this Spotted Turtle population to others in Massachusetts and the Northeast can help inform regional conservation efforts.

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