Fishery Biologist, Brian Fillmore, assesses alligator snapping turtle hatchlings in incubator, May 2008, at the Tishomingo NFH, Oklahoma. Photo by Staff.

With five year classes of alligator snapping turtles, including the current 2008 class, monthly growth assessments are ongoing at the Tishomingo National Fish Hatchery.  In the 2004 year class, with an average mass of 1997 grams, the average monthly increase in mass for those kept in the turtle culture building tank was 123 grams, while the average increase in mass for the turtles in a pond was 69 grams over their average mass of 1385 grams.  Overall, this 2004 year class averaged an increase in body mass during one month of 5%.  Carapace length increased 7.3 centimeters on the turtles kept in the culture house, as compared to 5 centimeters on the turtles in a pond on station.

In the 2007 year class, there was significant increase in the mass of the alligator snapping turtles.  The group kept in the incubator at a constant temperature with an average mass of 60.5 grams, gained 22 grams over one month.  The turtles in culture house tanks with an average mass of 49 grams gained 20 grams during one month.  Overall in this 2007 year class, the average growth rate is 38.5%.  Carapace length increased 2.5 centimeters.