Consequences of Variation in Dietary Protein on Captive-raised Black Knob Map Turtles (Graptemys nigrinoda, emydidae)
Many turtle species are threatened with extinction worldwide. Because of their slow maturation rates, low juvenile survivorship and slow population recovery status, more aggressive conservation tools including captive propagation may be required to prevent extinctions. Captive propagation is the practice of hatching eggs in an environment with fewer natural predators, better living conditions, and consequently decreased mortality. Often adults are kept to create a "farmed population" and the juveniles are released into the natural habitat. However for any conservation tool to be effective, the released juveniles must have a realistic chance of survival and reproductive success in the natural environment. This study was designed to gather information about the potential consequences ( e.g. growth and mortality) of variable protein diets on captive-hatched juvenile Graptemys nigrinoda (Black Knob Map Turtle). The experiment had two distinct parts: a 9-month exposure to one of three dietary proteins, followed by a 9-month exposure to the medium-level dietary protein. Over the variable portion of the experiment, all three diets had significantly different growth curves. After the 9-month medium protein level diet, all turtles, regardless of previous protein level, achieved the same end point. Importantly for propagation efforts, juvenile mortality does appear to be related to protein level; the highest dietary protein level sustained the fewest number of mortalities while the lowest protein had the lowest survivorship.
Map turtles, Proteins in animal nutrition, Mortality
Burpo, N. (2004). <i>Consequences of variation in dietary protein on captive-raised black knob map turtles (Graptemys nigrinoda, emydidae)</i> (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.