The Pearl River Map Turtle, Graptemys pearlensis, described by Ennen et al. (2010), was originally included as part of Graptemys pulchra Baur 1893 and then Graptemys gibbonsi Lovich and McCoy, 1992, with specimens from the Pearl River drainage referenced in both original descriptions of those taxa. This taxonomy has been accepted by Lindeman (2013) and TTWG (2021).

The Pearl River Map Turtle, Graptemys pearlensis, is assessed as Endangered (EN) based on criteria A2bce+4ce. Available information indicates that populations of the species have apparently declined by >50% since ca 1975, a time period representing ca three generation lengths (ca 50 years), meeting the criteria for an assessment of Endangered (EN A2bce). While the worst impacts from pollution and habitat destruction have apparently become less severe, habitat quality has not been restored to optimal conditions, while impacts from hurricane aftermath continue to be of concern and estimation of ongoing threats suggest that the species also meets criteria for EN A4ce ongoing over the past two generations (ca 34 years) and the next one generation (ca 17 years). Thus G. pearlensis qualifies as Endangered A2bce+4ce. The species was previously assessed as Endangered (EN A1bcde+4bcde) (van Dijk 2011).

Graptemys pearlensis is restricted to the main stems and major tributaries of the Pearl and Bogue Chitto rivers of Louisiana and Mississippi, USA (Ennen et al. 2010, 2016; Lindeman 2013; TTWG 2021). The occupied section of suitable habitat in the Pearl is about 800 km and the occupied section of the Bogue Chitto about 140 km, for a total estimated length of 940 km of occupied river length. The species is known from 16 counties of Mississippi (Attala, Columbia, Copiah, Hancock, Hinds, Lawrence, Leake, Lincoln, Madison, Neshoba, Pearl River, Pike, Rankin, Simpson, Smith, and Walthall) and in two parishes of Louisiana (St. Tammany and Washington) (Lindeman et al. 2020). The estimated historical indigenous range (area of occupancy, AOO) was 14,378 sq. km, and its estimated historical indigenous extent of occurrence (EOO) was 32,489 sq. km (TTWG in press). The estimated current range based on linear river km is about 1,880 sq. km (2 km per river km), and the estimated current AOO is <500 sq. km.

Relative abundance of Graptemys pearlensis and its sympatric congener, G. oculifera, has been recorded periodically between the late 1990s and mid 2010s at five widespread sites along the mainstem Pearl River, using basking traps (Selman and Jones 2017). In addition, basking survey data from the entire drainage including tributaries (collected 2006–2018) were used to estimate the global population of the species at ca 21,841 individuals (Lindeman et al. 2020). Populations are relatively continuous along river reaches, as long stretches without any G. pearlensis are not known to occur (Selman and Jones 2017, Lindeman et al. 2020, Selman 2020). Overall, populations of G. pearlensis are estimated to be decreasing, likely with a more severe decline during the late 1900s and slower rate of decline more recently. The more severe declines of the late 1900s are inferred from relatively scant historical relative abundance data on the ratio of G. pearlensis to G. oculifera (Lindeman 1998, 1999; Lindeman et al. 2020). Whereas the ratio of the two species once was closer to 1:1, from the late 1980s onward, the ratio has been highly skewed toward G. oculifera, at ratios as high as 1:10 or 1:20 in some areas. Relative abundance and catch-per-unit-effort data on G. oculifera and G. pearlensis were collected in replicated trapping efforts on five stretches of the mainstem Pearl River in 1988, 1989, 1990, 1994, 2002, 2008–09, and 2013–14. Each species declined in catch-per-unit-effort at three of the five sampling sites, albeit not at the same sites, and G. oculifera predominated strongly at all five sites.

Females of Graptemys pearlensis can reach 29.5 cm in straightline carapace length (SCL), and the much smaller males reach only 12.1 cm CL (Ennen et al. 2016). Hatchlings measure from 36–40 mm CL (P.V. Lindeman, unpubl. data). Clutch size ranges from three to nine eggs (mean 6.4; Vogt et al. 2019). Eggs are typically 38–40 mm long, 26–27 mm wide, and weigh 15–17 g (Ennen et al. 2016, Vogt et al. 2019). Females mature at ca 20.5 cm SCL and 8–10 years of age (Lovich et al. 2009). Females produce eggs annually, with up to three clutches in a year between May and August (Vogt et al. 2019), thus mean annual fecundity is 19.2 eggs, assuming three clutches of the mean clutch size, with the most productive females potentially laying over 25 eggs in a year. Longevity for the species is unknown; however, Jones (2017) estimated maximum longevity of the smaller and earlier-maturing sympatric congener, G. oculifera, at 68 years for males and 88 years for females. Females have hypertrophied jaws and jaw musculature and consume bivalve molluscs almost exclusively, in particular invasive Asian clams (Corbicula spp.), which invaded the Pearl River drainage in the 1960s (Lindeman 2000, McCoy et al. 2020, Vučenović and Lindeman 2021). Males, which are more moderately broad-headed and much smaller in body size, consume far less in the way of molluscs, subsisting primarily on aquatic insect larvae, in particular trichopteran (caddisfly) larvae. Females of the similar and closely-related G. gibbonsi were estimated to mature at an age of 15–20 years (Selman in Lovich et al. 2009). Assuming an age at maturity of eight years, generation length of G. pearlensis is estimated to be 17 years (Iverson 2024).

Besides collection for the pet trade, G. pearlensis is also threatened by various forms of river degradation (pollution, impoundment, contamination, sedimentation, gravel mining, channelization, and de-snagging channels) that lead to declines in their preferred molluscan prey and the availability of basking and nesting sites (Ennen et al. 2016, Lindeman et al. 2020). Wanton shooting by individuals who use turtles for target practice also contributes to declines (Ennen et al. 2016). One large impoundment on the middle Pearl River, the Ross Barnett Reservoir, has resulted in substantial loss of habitat and additional impoundments of the Pearl have been considered and debated (Lindeman 2013, Selman 2020). Overall, the Pearl River Map Turtle inhabits river reaches with more widespread and intensive human impact and less riparian habitat preservation than its closely related congener, the Pascagoula Map Turtle, G. gibbonsi. Riverine pollution has been particularly significant in the Pearl River system as a result of riverside paper industries, and riverine gravel mining (review in Lovich et al. 2009). In addition, the river has suffered significant impact from hurricanes. Because of the connectivity of river mainstem habitat, a catastrophe somewhere in the river basin will affect the entire turtle population (and/or its prey base) in the downstream parts of that river, increasing the species’ vulnerability to impacts elsewhere in the basin.

Map turtles identified as Graptemys gibbonsi have been extensively traded in the global pet trade; collecting efforts for the species have included the Pearl River basin (Selman and Qualls in Lovich et al. 2009), meaning that an unknown but certain proportion of the animals traded as G. gibbonsi were actually G. pearlensis.

Graptemys pearlensis, as former part of G. gibbonsi, is protected from commercial exploitation in Mississippi and possession is limited to four individuals. Its Louisiana populations are considered an Animal of Conservation Concern. All broad-headed Graptemys spp. (G. barbouri, G. ernsti, G. gibbonsi, G. pearlensis, and G. pulchra) have been proposed for inclusion as Threatened under the Endangered Species Act (ESA) (Lindeman 1999, Selman and Qualls 2007, USFWS 2021). The genus Graptemys was included in CITES Appendix III (United States) since 2006 and all broad-headed Graptemys spp., including G. pearlensis, have been included in Appendix II since 2023.

Graptemys pearlensis is likely to benefit from conservation measures in place for sympatric G. oculifera, including turtle-sensitive channel management practices in the 19 km section of the Pearl River designated as ringed map turtle sanctuary (Jones and Selman 2009). The Knoxville Zoo collected several juvenile G. pearlensis in 2018 to begin a captive assurance colony.

The primary research need for G. pearlensis is an analysis of its prey base and how its abundance correlates with that of the species throughout the Pearl River drainage, as well as how prey abundance is influenced by various forms of river degradation. Nesting by G. pearlensis has been little studied and similar analysis is needed for how nesting habitat availability correlates with abundance and population structure and how human actions impact nesting habitat.