NPS photo

Kemp's ridley sea turtle returning to sea with a transmitter attached.

During each year from 1997-2008, satellite transmitters were attached to the backs of a few Kemp’s ridley turtles that nested on North Padre Island or Mustang Island, Texas. Movements of 34 individual adult females were monitored. Forty-three transmitters were deployed; two turtles received transmitters during three different nesting seasons, five received transmitters during two different nesting seasons, and 27 received one. Of the 34 individuals, 23 were from the wild stock, 9 were head-started turtles (reared in captivity for the first months of life) that had been imprinted to Padre Island as hatchlings, and 2 were head-started turtles that had been obtained directly from Mexico as hatchlings.  

Kemp’s ridley turtles nest an average of 2.5-3.0 times per nesting season. Movements were tracked as a means to predict where and when the turtles might nest again, to aid with nest detection. They were also tracked to determine where the turtles go between successive clutches (inter-nesting) in a nesting season and after they have completed nesting for the year (post-nesting), to help identify habitats used in the Gulf of Mexico.

Locations were obtained from 9 to 841 days following deployment. Transmissions ceased when the transmitters failed or fell off.

After they completed nesting for the season, most of the tracked turtles left south Texas and traveled northward, parallel to the coastline, with their last identified location in the northern or eastern Gulf of Mexico. Inter-nesting residency was documented off south Texas and post-nesting residency in U.S. Gulf of Mexico waters from south Texas to the tip of Florida. Movements and habitat utilization by wild and head-started turtles and by individuals during different tracking events were generally similar. However, all of the 6 turtles that briefly traveled southward to waters off the coast of Mexico were wild. Tracking data were used to aid with nest detection and protection, and development of a regulation by Texas Parks and Wildlife Department that closed near-shore south Texas water to shrimp trawling. Findings from this study demonstrate the importance of near-shore Gulf of Mexico waters, particularly offshore from south Texas, to nesting Kemp’s ridley turtles.

Tracking maps from the later project years can be viewed at www.seaturtle.org/tracking/ under the Padre Island National Seashore Kemp’s ridley project.