NPS photo

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

Padre Island National Seashore conducts a variety of monitoring and research activities pertaining to the Kemp’s Ridley Sea Turtle Recovery Program and nesting by other sea turtle species on the Texas coast. Padre Island National Seashore is the only location in Texas where nests from all five sea turtle species that occur in the Gulf of Mexico have been documented. 

Nesting and Results of Experimental Imprinting and Head-Starting

The scarcity of Kemp’s ridley turtles in the 1970’s prompted the United States to join on-going efforts in Mexico to save this endangered species. From 1978-1988, an international project was begun to re-establish a nesting colony of Kemp’s ridley turtles at Padre Island National Seashore as a safeguard against extinction. Overall, 22,507 eggs were collected in Rancho Nuevo, packed in Padre Island sand, and transported to the National Seashore where they hatched in controlled conditions. The resulting hatchlings were released on the beach at the National Seashore, allowed to crawl into the surf, and captured using aquarium dip nets. It was hoped that this exposure to the Padre Island sand and surf would imprint the turtles to the National Seashore so that they would return here to nest at adulthood. Padre Island National Seashore was selected for this effort since Kemp’s ridley is a native nester there and protection could be afforded to the nesting habitat, turtles, and eggs since it is a unit of the National Park Service system.   

In 1986, Padre Island National Seashore began systematic efforts to detect, investigate, and protect nesting by Kemp’s ridley and other sea turtles on the Texas coast. These efforts have grown over the years, with the addition of several other partners and projects outside of the National Seashore. 

The Chief of the Division of Sea Turtle Science and Recovery at the National Seashore tallies and reports sea turtle nesting that is documented on the Texas coast. Information reported includes nests by species, nesting distribution, nesting dates, number of eggs, hatchling success, and embryological development of unhatched eggs. Through tagging and examination for tags, the National Seashore works with partners to gather and report data regarding results of experimental imprinting and head-starting, inter-nesting intervals, remigration intervals, site fidelity, age and size at maturity, and number of nests per individual (Shaver, 2005). We are also conducing genetics research in collaboration with NOAA-Fisheries to expand our knowledge of these parameters by performing kinship analysis for nests of unknown maternity, and to confirm species identification of nests. These research and monitoring efforts are providing information important to the management of the species in Texas. 

The first known female that returned to nest from the experimental imprinting and head-starting project was in 1996. This turtle had been hatched at Padre Island National Seashore in 1983. Marked females from this program and other Kemp’s ridleys have been nesting during every year since 1996 (except 1997 when only wild stock turtles were documented). Nesting is increasing (doubling every 1-3 years) and most Kemp’s ridleys nesting on the Texas coast now are from the wild stock (Shaver, 2005, unpublished data). 

The following are Kemp ridley female turtles that have returned to nest in the gulf beaches this year (2008). These turtles were experimentally imprinted (in the past), or are of wild stock.

Claudine (82214)

Claudine is a Kemp’s ridley sea turtle from the 1987 year-class that was experimentally imprinted to Padre Island National Seashore and head-started. She was outfitted with a satellite transmitter after nesting on North Padre Island north of Padre Island National Seashore on April 24, 2008. She was also recorded nesting at Padre Island National Seashore once during 2001 and twice during 2005. During those other two years she was also outfitted with a satellite transmitter, so this is her third tracking event.

Linda (82215)

Linda is a Kemp’s ridley sea turtle from the wild stock. She nested at Padre Island National Seashore on April 24, 2008 and was one of six Kemp’s ridleys recorded nesting there that day. Linda was also recorded nesting at Padre Island National Seashore during 2002 and 2006.

Dora Jean (82216)

Dora Jean is a Kemp’s ridley sea turtle from the wild stock.  She nested at Padre Island National Seashore on 24 April, 2008 and was one of six Kemp’s ridleys recorded nesting there that day.  Dora Jean was also recorded nesting at Padre Island National Seashore twice during 2006.

Incubation of Sea Turtle Eggs

Eggs from sea turtle nests found on the Texas coast are protected from a variety of human-related and natural threats that would impact their survival. Data are collected for incubating and hatched eggs to determine results of experimental imprinting and head-starting and to assess and improve incubation techniques. Since 1982, data have been collected on incubation temperatures and sex ratios (Shaver et al., 1988, Shaver, 2005) of sea turtle clutches incubated on the Texas coast and recently the University of Alabama at Birmingham and U.S. Fish and Wildlife Service joined as collaborators in this research. Incubation temperatures determine the sex of sea turtles, with warmer temperatures producing primarily females. A female dominated sex ratio is being produced both in Texas and in Mexico (Shaver, 2005; Wibbels, personal communication).   

Satellite Tracking Nesting Females

During each year since 1997, satellite transmitters have been attached to a few Kemp’s ridley turtles returning to the sea after laying eggs at Padre Island National Seashore. Kemp’s ridley turtles nest an average of 2.5 times per nesting season. Movements have been tracked as a means to predict where and when the turtles might nest again. They have also been tracked to determine where the turtles go between successive clutches in a nesting season and after they have completed nesting for the year, to help identify areas of the Gulf coast that might need special protection. The transmitters can last up to 24 months on their backs before failing or falling off. Information from the transmitter/receiver data shows that the turtles are primarily inhabiting shallower waters along the Gulf of Mexico coastline, including waters off the state of Tamaulipas, Mexico, and U.S. Gulf Coast states. Many of the adult females have been tracked to the crab-rich shallow waters off Louisiana, around the Mississippi Delta, but some have ventured as far as the western tip of Florida. Some of these tracking maps can be viewed at www.seaturtle.org/tracking/ under the Padre Island National Seashore Kemp’s ridley project.