Hal Perry says the province needs to do more to prevent anoxic rivers. (CBC)

Hal Perry, the Opposition's environment critic, is calling on the P.E.I. government to do something to prevent Island waterways from becoming anoxic.

So far there have been 18 anoxic events this summer, two more than all of last year.

Excessive nutrients in rivers start a chain reaction. Algae grow in huge masses, then die. As algae rot, oxygen is consumed in the water, a condition known as anoxia.

These anoxic events can go on for days or weeks. When oxygen levels get too low, it's hard for anything to survive in the waterways.

Warmer water temperatures and increased sea lettuce are causing part of the problem.

The Hunter-Clyde Watershed Group also called on the provincial government recently to help protect waterways.

Perry said the situation is getting worse and demands government attention.

"It’s getting to be very, very serious," Perry said.

"Every year it’s becoming more and more public knowledge. People are becoming more educated.

"I'm hearing a lot of concern. There [are] a lot of oyster fishermen, clam fishermen, shellfishers, who have major concerns over this and they have for years."

He criticized the government for cancelling a pilot project on sea lettuce harvesting.

"Last year with the sea lettuce pilot project there was a sign of hope for them," said Perry.

"It took a while before the results came back in, but the minister now is not going to further that project and I think it's really needed."

Environment Minister Janice Sherry is taking a lax approach to dealing with the serious problem affecting the health of Island waterways, Perry said.

He said the government needs to work with local watershed groups to come up with a solution.

The provincial Environment Department did not put forward a representative to respond to Perry's comments on Tuesday.