FAQ

Monitoring Ontario Tadpoles

Amphibians have been the focus of tremendous research efforts as information supporting the notion of worldwide amphibian declines has entered the main stream. These efforts have unearthed many fascinating aspects of amphibian life in the world's lakes, rivers, streams and wetlands. Research has shown that amphibians are extremely sensitive creatures. They are easily impacted by habitat destruction, UV radiation, climate change, disease and a myriad of toxins. Within the past decade, these factors have had devastating effects of amphibian populations around the globe.

There have been public reports of catastrophic tadpole die-offs in several bodies of water within Ontario. These reports have come from a variety of sources; amateur naturalists, concerned cottagers, and groups of curious schoolchildren. As a result, researchers at Trent University have begun to seek information regarding these die-offs. These initial reports have spawned The Tadpole Monitoring Project.

The goal of this project is to assess the occurrence and causes of catastrophic die-offs of amphibian tadpoles, in the wetlands at the James Oliver Ecological Research Center, and in other wetlands in the associated region. Amphibians are relatively abundant in the
ponds and adjacent wetlands at the Oliver Center which is located on the north shore of Pigeon Lake. In the past three years, the wood frog tadpoles developing in the primary woodland pond on the Oliver site all died prior to metamorphosis. In the early spring, the pond has been found to have healthy wood frog broods, which begin to develop normally. As development continues, the animals begin to exhibit signs of illness characterized by redness in the mouth, vent and abdominal region and system wide hemorrhages have been noted in post-death examinations. Similar die-offs of tadpoles, have also reported from other wetlands in the region.

If such die-offs are occurring, and may be occurring more frequently in the years ahead, the implications concerning community stability and health are serious. Humans may be acting as vectors for this disease which may prove fatal for native fish and amphibian populations. These outbreaks should be given serious attention because they may signal environmental change on such a global scale that many groups of organisms, including humans could be threatened (Carey et al, 1999).

This project is the beginning of a long-term study that is likely to expand over the years, providing a critical and unique opportunity for comparison of the occurrence of tadpole die-offs over the next decades.

Carey, C., N. Cohen, and L. Rollins-Smith. (1999). Amphibian declines: An immunological perspective. Developmental and Comparative Immunology. 23: 459-472.