Frog Decline Experiment in Ome City, Tokyo - January 2000

Frog Decline Experiment in Ome City, Tokyo - January 2000

An experiment conducted in Ome City, Tokyo, investigated the impact of ultraviolet (UV) rays on the hatching rate of frogs. The experiment was carried out in fallow rice paddies, where frog eggs were divided into two groups: one covered with a UV-blocking filter and the other without the filter. The group covered with the filter hatched approximately 190 eggs, while the uncovered group hatched only 149 eggs. The filter blocked about 90% of UV rays, effectively reducing the harmful effects on the hatching process.

Additionally, frog populations in Ome City have decreased by about 25% over the past 10 years, with increased UV radiation being identified as one of the contributing factors. During the experiment, the UV intensity measured an average UV Index of 7 during summer daylight hours, indicating significant damage to the frog eggs. The rise in UV levels is attributed to ozone layer depletion and climate change.

### Similar Experiments Overseas
Similar experiments have been conducted in Colorado, USA, and Queensland, Australia. In Colorado, a study on northern leopard frogs (Rana pipiens) found that the hatching rate decreased by about 30% when exposed to UV rays. In Queensland, it was reported that frog species with low UV tolerance are significantly declining in certain areas, prompting the development of UV protection technologies.

The impact of UV radiation on frog populations is a global issue, with international research ongoing. Frogs are considered an important indicator of ecosystem health, and the effects of UV radiation extend to food chains and water pollution risks.