Rainy weather didn't stop volunteers from performing an important task on Earth Day -- counting eels in the Hudson River.

The task sounds unusual, but it is important because the tiny eels are an indicator species. That means they measure the health and cleanliness of the Hudson River.

Students from Lincoln High School suited up to step in the river and gather the fish collected in nets. They are then weighed at the Sarah Lawrence Center for the Urban River at Beczak.

The eels travel from the Sargasso Sea in the Atlantic Ocean to the Hudson River. The number of fish caught thus far is more than double last year's numbers.

The program is not only about counting fish, it also educates the public and inspires future environmental scientists.

The eel count continues for five more weeks after Monday.