MEPS 559:217-229 (2016)  -  DOI: https://doi.org/10.3354/meps11897

Ontogenetic shifts in diet and habitat of juvenile green sea turtles in the northwestern Gulf of Mexico

Lyndsey N. Howell1,2,*, Kimberly J. Reich1, Donna J. Shaver3, André M. Landry Jr.1, Catherine C. Gorga

1Sea Turtle and Fisheries Ecology Research Laboratory, Department of Marine Biology, Texas A & M University, Galveston, Texas 77553, USA
2NOAA, National Marine Fisheries Service, Protected Species Branch, Southeast Fisheries Science Center, Galveston, Texas 77551, USA
3National Park Service, Sea Turtle Science and Recovery Division, Padre Island National Seashore, Corpus Christi, Texas 78480, USA
*Corresponding author:

ABSTRACT: Effective management of a rapidly increasing juvenile green sea turtle Chelonia mydas population necessitates an understanding of the foraging grounds utilized throughout ontogeny. We used stomach content (SCA) and stable isotope analyses (SIA) of multiple size classes of green turtles foraging along the middle (MTC) and lower Texas coasts (LTC) in the northwestern Gulf of Mexico to identify ontogenetic shifts in foraging behavior. Spatial differences in diet and habitat residency were examined based on samples gathered from live (n = 55) and deceased turtles (n = 114). Additionally, the isotopic composition of putative forage material within nearshore and inshore habitats was investigated to determine prey contribution to diet. Green turtle recruitment to neritic channel environments in Texas waters at sizes <25 cm straight carapace length (SCL) was established based on the presence of benthic macroalgae in the diet. Integration of SCA with SIA of carbon and nitrogen in scute material, as well as potential prey, revealed a subsequent inshore shift to seagrass beds before obtaining 35 cm SCL for turtles of the LTC, while turtles from the MTC exhibited considerable variation in size at transition. This study improves our understanding of the feeding ecology of green turtles within critical foraging grounds along the Texas coast.


KEY WORDS: Green turtle · Chelonia mydas · Ontogenetic shift · Stomach content analysis · Stable isotope analysis · δ13C · δ15N · Gulf of Mexico · Texas


Full text in pdf format
Supplementary material 
Cite this article as: Howell LN, Reich KJ, Shaver DJ, Landry Jr AM, Gorga CC (2016) Ontogenetic shifts in diet and habitat of juvenile green sea turtles in the northwestern Gulf of Mexico. Mar Ecol Prog Ser 559:217-229. https://doi.org/10.3354/meps11897

Export citation
Mail this link - Contents Mailing Lists - RSS
- -