MCCOMBE, A.C.*; BJORNDAL, K.A.; BOLTEN, A.B.; Univ. of Florida, Gainesville; Univ. of Florida, Gainesville; Univ. of Florida, Gainesville: Compensatory Growth in Chelonia mydas

Many organisms demonstrate plasticity in growth under different environmental conditions. Compensatory growth, a period of accelerated growth during increased food intake following nutritional deprivation, is an example of a plastic growth response to fluctuations in food availability. Sea turtle hatchlings are prone to fluctuations in food uptake (and thus to periods of slow early growth) due to nutrient dilution and heterogeneity of prey distribution. The purpose of this study was to evaluate the capacity of green turtle hatchlings for compensatory growth and to elucidate the physiological effects of different intake and growth patterns in green turtle hatchlings. This twelve-week study was conducted at the Cayman Turtle Farm, Grand Cayman. One group of turtles was fed ad libitum for twelve weeks, another was fed a restricted diet for twelve weeks, and the third was fed the restricted diet for five weeks followed by the ad libitum diet for seven weeks. Intake rates, growth rates, conversion efficiencies, body composition, and gut morphology were evaluated. Hatchlings demonstrated compensatory growth as a result of improved food conversion efficiency rather than hyperphagia. Turtles on a restricted diet had decreased lipid, energy, and organic matter content relative to turtles on an ad libitum diet. Additionally, food restriction caused a reduction in liver and gut size. After a period of realimentation and compensatory growth, previously restricted turtles were indistinguishable from ad libitum turtles in body composition and gut morphology. These results suggest that green turtle hatchlings exhibit a plastic response to fluctuations in food availability, allowing them to mitigate the effects of slow early growth on body size, body composition, and gut morphology.