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Preliminary Development of Aquatic Turtle Aerial and eDNA Survey Methods in the Sabine River Basin


This study aims to address the following objectives:

  1. Assess turtle species composition at select sites using visual survey methods;
  2. Evaluate the viability of aerial imagery from unmanned aerial vehicle (UAV) survey techniques as a method for documenting species presence at select sites; and
  3. Determine presence or absence of the western chicken turtle at select sites using environmental DNA (eDNA) sampling techniques.

Study Area

Sabine River Basin

Project Period



The Sabine River Basin is home to numerous turtle species, including some currently under review for inclusion on the Endangered Species Act (ESA). Specifically, petitions to list the western chicken turtle (Deirochelys reticularia miaria; WCT) and alligator snapping turtle (Macrochelys temminckii; AST) under the ESA have been submitted to the U.S. Fish and Wildlife Service with significant 90-Day Findings. Currently, the WCT is listed as endangered in Missouri and is a species of greatest conservation need in Louisiana and Oklahoma, but holds no protection status in Texas. EIH researchers are currently conducting surveys for the WCT throughout its historic range. Conversely, the AST is recognized as a threatened species in Texas (TAC 65.175).

Data collected via this work will directly supplement the ongoing work that EIH is conducting for the Comptroller related to the WCT, and will provide baseline data necessary for overall basin-wide turtle surveys in future years.


Gordon, M.L., Nagro, J., Mokrech, M., Oakley, J., and Guillen, G. 2021. Preliminary development of aquatic turtle aerial and eDNA survey methods in the Sabine River basin. EIH Report 2021-001, 29 pp.

Project Sponsors

Sabine River Authority of Texas

Related links

USFWS Species Profile: Western Chicken Turtle

USFWS Species Profile: Alligator Snapping Turtle