Sea Turtles at the Mansfield Channel

and in the Laguna Madre

The Mansfield Channel [left, click to enlarge] is located at the southern end of Padre Island National Seashore, along the south Texas coast. The Mansfield Channel is one of only two direct routes of passage between the Gulf of Mexico and the Laguna Madre. A pair of jetties armor the Gulf of Mexico entrance to the channel. The Mansfield Channel and Laguna Madre provide important habitat for foraging, developing, resting, and migrating sea turtles.

Four sea turtle species, including the green (Chelonia mydas), hawksbill (Eretmochelys imbricata), Kemp's ridley (Lepidochelys kempii), and loggerhead (Caretta caretta) are documented in the vicinity of the Mansfield Channel. The Mansfield Channel and Laguna Madre are particularly important to juvenile green turtles, which were once commercially exploited in south Texas. A variety of human activities are conducted at the Mansfield Channel and in the Laguna Madre (dredging, boating, fishing, etc.).

The National Park Service (NPS), National Marine Fisheries Service (NMFS), Texas Parks and Wildlife Department, and U.S. Fish and Wildlife Service (USFWS) needed additional information on sea turtles inhabiting the Mansfield Channel and in the Laguna Madre, in order to afford these threatened and endangered species adequate protection. The objective of this project was to conduct a survey to gather a variety of biological data for sea turtles inhabiting the Mansfield Channel and Laguna Madre. Sea turtles were netted at the Mansfield Channel jetties from 1989 through 1997 and catch-per-unit-effort (CPUE) was compared between study months and years. Netting and stranding data were compared.  A cooperative study of habitat utilization and movements of juvenile green turtles was undertaken during 1996-1997 using satellite telemetry.  A habitat utilization model was developed for green turtles in the Laguna Madre using satellite-tracking and stranding data.