by Heather Lowe
The TSA assembled a team recently to travel to Belize to begin implementation of two grants designed to improve our understanding of the captive reproductive biology of the Central American River Turtle, Dermatemys mawii, locally known as the Hicatee. The grants – courtesy of the American Zoo Association and Disney Worldwide Conservation Fund – will support research that should shed new light on the mysteries of managing and reliably breeding this species in captivity, and will eventually lead to a sustainable and larger-scale effort intended to take pressures off of wild populations. Hicatee are hunted extensively throughout their range in Mexico, Guatemala and Belize, and many populations are heavily depleted.
In February we assembled a team to
1) conduct evaluations of the turtle’s health and reproductive status
2) to test water quality and look at methods to improve it
3) discuss nesting habitat based on the one nest we have
4) discuss incubation techniques based on our knowledge of the embryonic diapause that eggs of this species undergo
5) begin preparing a film that would document the goals of project
Team Hicatee included
• Thomas Rainwater, PhD (USFWS), the biologist that did the 2010 field assessment with a long history and familiarity of working in Belize
• Shane Boylan, DVM (South Carolina Aquarium), an outstanding chelonian clinician with a broad knowledge of water quality and testing. Shane brought a portable ultrasound for evaluating the females reproductive status
• Mallory Clark (Tennessee Wildlife Safari), an aspiring film-maker who documented the project with an eye to producing a film
We were hosted by Jacob Marlin, BFREE Director and Tom Pop, BFREE employee who oversees the HCRC and provides daily care for the turtles.
Over the course of four days, the team drained the pond, captured the turtles and conducted health exams , weighing and measuring them all, and doing ultrasound exams on the females to determine where they are in their cycle. All females appeared to have either laid eggs already or they did not cycle this year – not unexpected considering their transition to a novel environment. All turtles had gained considerable weight, especially the sub-adults, which added more that 1 kg in a year’s time. We brought water testing kits and our quality is excellent. We discussed ways to improve oxygenation to the ponds and are currently evaluating solar powered pumps and sprayers. We spent considerable time devising a husbandry and management plan based on what we know of the reproductive patterns of wild Hicatee. They are a challenging turtle in captivity and replicating their nesting environment will be based on trial and error. Also, what are the environmental cues that trigger egg-laying? The ponds were designed with the ability to fluctuate water levels, which we believe is an important variable. Incubation can be challenging as well, and duplicating the conditions necessary to induce, and then break out of, embryonic diapause, were the topics of long discussions. Overall the team feels we have a solid plan for working out the intricacies of the breeding pattern of this difficult species, and that success will be forthcoming. We will continue monitoring the reproductive cycle throughout the year with ultrasound, so that we are prepared for egg-laying. Stay tuned as we bring you exciting news from this project, and hopefully pictures of hatchling Hicatees in the near future.