Mass Die Off Of Wood Frog Tadpoles Concerns Scientist
July 31, 2014
A mass die off of wood frogs (Lithobates sylvaticus) in a half-acre pond in Brunswick, Maine has caused concern for the scientist who owns the pond. Every spring, Nat Wheelright, a biology professor at Bowdoin College in Maine looks forward to the wood frog tadpoles that grow up in his backyard pond. Last year was no different as frogs mated in his pond and hundreds of thousands of tadpoles began their lifecycle, Wheelright told Maine NewsCenter.
However, in mid-June 2013, in a single 21 hour period, virtually all of the estimated 200,000 tadpoles perished. Perplexed and mildly disappointed that the tadpoles died off, Wheelright, being the biologist that he is, sent tadpole samples to other biologists at the University of Maine and the University of Tennessee for analysis.
His colleagues ran tests which revealed that the tadpoles died from very high levels of ranavirus in their systems. What was especially of interest to Wheelright was how the virus completely wiped out the entire population of tadpoles in his pond at the same time, rather than over time. What is also interesting is that the other five or six amphibian species that call the pond home were seemingly not affected by the virus. He believes the mass die off is related to some other stressor, such as high temperatures, lack of food, or the introduction of pesticides in the water.
Wood frogs returned to the pond this spring to mate, however, none of the tadpoles survived to maturity this summer, which has caused Wheelright some concern.
"If this were to happen for three, four or five years in a row, then we would see a consequence, at least for this population," he told NewsCenter.
Ranavirus is a fairly new disease that was discovered in a leopard frog (Lithobates sp.) in the 1960s and first seen in the wild in the 1980s. It affects mostly amphibians but also infects certain fish and reptiles, including box turtles, certain tortoises and geckos and green tree pythons (Morelia viridis).
John B. Virata keeps a ball python, two corn snakes, a king snake, and two leopard geckos. His first snake, a California kingsnake, was purchased at the Pet Place in Westminster, CA for $5. Follow him on Twitter @johnvirata