Herpetological Conservation and Biology 8(1):141 – 148. Submitted: 17 September 2012; Accepted: 20 December 2012; Published: 30 April 2013. GROWTH AND VIABILITY OF A TRANSLOCATED POPULATION OF ALLIGATOR SNAPPING TURTLES (MACROCHELYS TEMMINCKII) 1,4 2,5 3 1 DANIEL B. MOORE, DAY B. LIGON, BRIAN M. FILLMORE, AND STANLEY F. FOX 1 Department of Zoology, Oklahoma State University, Stillwater, Oklahoma 74075 2Department of Biology, Missouri State University, Springfield, Missouri 65897 3Tishomingo National Fish Hatchery, Tishomingo, Oklahoma 73460 4Present address: Biological Sciences, Murray State College, Tishomingo, Oklahoma 73460 5Corresponding author, e-mail: [email protected] Abstract.—Exploited for food, traditional medicine, and pets, many turtle populations have been over-harvested or even extirpated from historic ranges. Most turtles possess life-history characteristics that complicate conservation efforts. These characteristics include delayed sexual maturity and high embryo and juvenile predation rates. Restoration strategies include nest protection, head-starting, and translocations. We examined short-term results of these strategies on a reintroduced population of Alligator Snapping Turtles (Macrochelys temminckii) in southern Oklahoma. We released 16 hatchery-raised juveniles and 249 adult M. temminckii into pools adjacent to the Washita River near Lake Texoma on the border of Texas and Oklahoma, USA. We tracked mortality and conducted nest searches to document factors related to population sustainability. We used hoop nets to recapture individuals and track growth. We confirmed seven mortalities during 2007 and none in 2008. In 2007 we located eight nests, all of which were depredated, and 18 nests in 2008, one of which was detected before depredation and successfully protected until hatching. We compared growth rates of released juveniles and members of the same cohort that were kept in captivity. There was no significant difference in dimensional growth, but released juveniles gained more weight than those retained at the hatchery. Key Words.—Conservation; growth; head-start; mortality; predation; reintroduction INTRODUCTION well documented (Sodhi et al. 2004; Alves et al. 2008). Anthropogenic influences leading to habitat loss, Freshwater ecosystems are among the most severely alteration, or fragmentation are unlikely to wane, as human-impacted ecosystems (Benke 1990; Lydeard and humans require and modify more and more water and Mayden 1995; Sala et al. 2000; Dudgeon et al. 2006). wetland habitat. Anthropogenic activities such as flood control, Turtles are long-lived and typically have high embryo agriculture, industry, urbanization, deforestation, mining, and juvenile mortality rates, delayed sexual maturity, and removal of water all contribute to the degradation of and protracted reproductive potential (Gibbons 1987; aquatic habitats and water quality, often at some distance Wilbur and Morin 1988; Congdon et al. 1994). These from the source of impact (Benke 1990; Lydeard and life-history characteristics make turtles vulnerable to Mayden 1995; Dudgeon et al. 2006). Deterioration of decline when exploitation of adults and juveniles is these habitats is a prime driver of loss of biological severe (Brooks et al. 1991; Congdon et al. 1993, 1994; diversity (Mitchell and Klemens 2000; Moll and Moll Heppell et al. 1996; Heppell 1998). The Alligator 2000; Bodie 2001; Palmer et al. 2010; Strayer and Snapping Turtle, Macrochelys temminckii, is not Dudgeon 2010). Biological diversity is essential to protected at the US federal level (United States Fish and ecosystem function (Duffy 2002; Cardinale et al. 2006; Wildlife Service 1991), but it is afforded varying levels Dudgeon et al. 2006). Aquatic turtles have important of protection in every state where it occurs (Buhlmann roles in aquatic food webs and system energetics (Lagler and Gibbons 1997). 1943; Paine 1966; Iverson 1982; Congdon et al. 1986; The best approach to turtle conservation is Moll and Moll 2004). maintenance of large functional ecosystems and Threats to aquatic turtles include alteration, preservation of viable populations within native ranges fragmentation, and loss of habitat, as well as exploitation (Soulé 1985; Snyder et al. 1996; Moll and Moll 2004). for food, pets, and traditional Asian medicine (Gibbons However, identifying and conserving large tracts of et al. 2000; Pritchard 2006). Turtles and turtle eggs have high-quality habitat is difficult and expensive. been harvested for food since the early Pleistocene Protection of natural diversity is tenuous, and is subject (Auffenberg 1981), throughout human history (Iverson to the political, economic, and cultural climate of the 1982; Frazer 2003), to modern times (Heinrich et al. region. Often, conservation biology is a “crisis” 2010). The use of turtle parts for medicine has also been discipline wherein particular ecosystems, habitats, or Copyright © 2013. Daniel B. Moore. All Rights Reserved. 141 Herpetological Conservation and Biology TABLE 1. Pool area, number of released turtles, sex, and male-to-female ratios of translocated Alligator Snapping Turtles (Macrochelys temminckii) in the Washita River drainage in Oklahoma, 2007. Total Unknown Male:Female Pool Hectares Turtles Males Females Sex Ratio A 4 30 16 12 2 1.3:1 B 15 27 11 14 2 0.8:1 C 14 39 11 15 13 0.7:1 D 381 30 17 9 4 1.8:1 E 138 31 19 10 2 1.9:1 F 44 62 26 21 17 1.2:1 G 141 30 15 10 5 1.5:1 species become critically threatened, necessitating and therefore originated from the Mississippi River intensive and reactionary conservation efforts (Soulé drainage. However, due to the large number of animals 1985; Lyles and May 1987). There are three primary involved and immediacy of the translocation, origins (reactionary) approaches to conservation of turtles: (1) were not validated with genetic testing. protection of nests, (2) head-starting/reintroduction, and Juvenile turtles were obtained from captive-bred stock (3) translocations (Siegel and Dodd 2000). produced at Tishomingo National Fish Hatchery in Protection of marine turtle nests has had variable Johnston County, Oklahoma. Recent surveys found that success (Dutton et al. 2005). This strategy typically the species declined over much of the western portion of involves patrolling nesting areas to discourage predators, its historic range (Riedle et al. 2005), and this facility application of predator exclusion devices, and/or implemented a captive propagation and head-start relocation of threatened nests to safer areas. Head- program in 1999 (Riedle et al. 2008) using adult M. starting has been used for several decades, primarily temminckii obtained from Sequoyah National Wildlife among marine species, but also has had a mixed record Refuge in east central Oklahoma. This native population of success (Frazer 1992; Bowen et al. 1994). There are has been shown to be genetically similar to other no management strategies that substitute for the populations within the Mississippi drainage (Echelle et protection of reproductively mature adults (Heppell et al. al. 2009). 1996; Heppell 1998). Here we report on our We recorded morphological measurements, including observations of nest predation, head-starting, and straight midline carapace length (MCL), midline plastron translocations of M. temminckii in Oklahoma. length (MPL), and mass. We released 249 adult turtles into seven pools (Fig. 1) at our study site on 11 April MATERIALS AND METHODS 2007 (Table 1). Turtles averaged 13.5 ± 7.5 kg (mean ± 1 SD). Mean MCL was 37.7 ± 6.6 cm, and mean MPL Adult turtles were confiscated in 2006 from a privately was 28.8 ± 4.9 cm. owned turtle farm in Arkansas that was in violation of We selected 16 juveniles (mass = 904 ± 136 g; MCL = permits. We obtained these turtles for reintroduction 14.8 ± 7.5 cm; MPL = 11.7 ± 2.9 cm) from the combined into portions of the historic range of M. temminckii in 2002 and 2004 cohorts at the hatchery. All received a Oklahoma. In spring 2007, a multi-state, multi-agency PIT tag and unique set of carapace marks as described effort (US Fish and Wildlife Service [USFWS], for the adults. We released these turtles 8 June 2007 into Oklahoma Department of Wildlife Conservation an oxbow where we had previously released adults. We [ODWC], Arkansas Game and Fish Commission, retained 26 juveniles from the combined 2002 and 2004 Oklahoma State University, and the Tulsa Zoo) moved cohorts at the hatchery for comparison with the ones these turtles from the Joe Hogan State Fish Hatchery in released to the wild. We fed these turtles fish-based Lonoke, Arkansas, where they were temporarily housed, pellets and live and dead fish ad libitum. Water to Tishomingo National Fish Hatchery. Each turtle temperatures fluctuated seasonally, and light cycles were received a health assessment from Tulsa Zoo and dictated by natural light exposure through windows. The Oklahoma State University veterinary staff, an implanted density at which we maintained turtles varied with size, Passive Integrated Transponder (PIT) tag (12 mm, 125 with larger animals housed at lower densities. However, kHz; Biomark, Boise, Idaho), and a unique series of growth rates of captive turtles were not density holes drilled in the posterior marginal scutes (Cagle dependent (unpubl. data). 1939). Information gleaned from the owners of the turtle farm by the Arkansas Game and Fish Commission Study site.—We chose seven permanent water bodies indicated that all turtles had been trapped in Arkansas adjacent to the Washita River