Oceanic survival and movements of wild and captive-reared immature green turtles (Chelonia mydas) in the Indian Ocean

Abstract

The ability of captive-reared turtles to survive in the wild is not precisely known, nor are movements of immature turtles in the open ocean. To provide information on these issues, a satellite tracking experiment was conducted in the western Indian Ocean to monitor oceanic movements of immature green turtles. Two wild turtles and four captive-reared individuals were tracked. The latter had been displaced after birth from nesting sites to a distant rearing site. Wild turtles survived after release, but did not move far away from release site. We hypothesize that this resident behaviour may be explained by stage-specific habitat requirements. Captive-reared turtles survived after release and migrated over thousands of kilometres. Among these, the oldest immature turtles retrieved the foraging sites of their native population, with movement patterns similar to those displayed by adults. Observed movements may be linked to hydrographic conditions such as general oceanic circulation, sea temperature and thermal fronts.

Sea Turtles of the Gulf of Mexico

“…They may remain in these areas for many years and then shift to other sites as larger juveniles (Zug and Glor 1998;Witherington et al 2006b). Some green turtles remain in the oceanic zone for extended periods (Pelletier et al 2003).…”

Satellite tracking of sea turtles: Where have we been and where do we go next?

“…Others have used satellite tracking to describe the behaviour of animals immediately following bycatch (Swimmer et al 2002, Chaloupka et al 2004a, Revelles et al 2007a, following rehabilitation and release (Bentivegna 2002, Cejudo et al 2006 or after extended periods in captivity (Pelletier et al 2003, Polovina et al 2006. This includes the year-long, transpacific tracking of the captive-raised loggerhead turtle from Mexico to Japan (Nichols et al 2000) and a comparison of wild adult females and those which had been headstarted (Shaver & Rubio 2008).…”

Population trends and survival of nesting green sea turtles Chelonia mydas on Aves Island, Venezuela

“…Recently, important efforts have been made to estimate population abundance and survival of green turtles based on long-term population monitoring using mark-recapture methods of nesting females (Balazs & Chaloupka 2004, Troëng & Rankin 2005, Koch et al 2007, Troëng & Chaloupka 2007 in foraging aggregations (Chaloupka & Limpus 2001, Bjorndal et al 2003, 2005b, Seminoff et al 2003, Campbell & Lagueux 2005, Patrício et al 2011, Colman et al 2015 and remote tracking of individuals using satellite telemetry (Pelletier et al 2003). However, a large variation has been observed among species, regions, and even populations (Casa le et al 2007, Troëng & Chaloupka 2007.…”