A new group of Islanders is looking for anoxic estuaries – lifeless coastal areas caused by oxygen depletion.

Anoxia in the waterways is caused by excess growth of vegetation from high nitrate levels, which start a chain reaction. As the aquatic plants die and rot, they suck oxygen from the water.

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.

Anoxic rivers turn greyish white or green, and stink. More extreme events can lead to the death of fish and shellfish.

P.E.I. Department of Environment, Labour and Justice map of anoxic estuaries on the Island. (P.E.I. Department of Environment, Labour and Justice)

The problem is becoming chronic on P.E.I., and hit the province early this year.

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

Sea lettuce often grows because of nitrates running into the water from neighbouring farmers' fields. But they can also come from cities and sewage, from forestry practices, and in some cases from industries such as seafood processing plants.

The group in the Kensington area is calling themselves the Anoxia Watchdogs.

Barry Murray, the executive director of Kensington North Watershed Association, started the group. He said farming is an important activity in the area.

"The Kensington area has a lot of land use – percentage wise – in agriculture and it's a great thing; it provides a lot of great people with good jobs and it's a huge part of our local culture and our economy," he said.

But he added that farming brings ecological challenges that must be addressed.

"Along with these benefits it also brings a few challenges and the nitrates in groundwater and surface water is a challenge that we have, and that we're trying to deal with," he said.

Murray also said that many anoxic events occur without ever being recorded. He hopes the new group can help record more of them so that the government will better understand the seriousness of the situation.

In June, Mike van den Heuvel, the Canada research chair in watershed ecology integrity at UPEI, was on the Wilmot River with a team sifting through the mounds of sea lettuce, examining how excess nitrogen is affecting the health of rivers in the Maritimes.

Van den Heuvel hopes to create a program that will allow the health of waterways to be monitored.

In July, provincial biologist Cindy Crane said the province is looking for help locating anoxic events.

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

The Department of Environment, Labour and Justice listed 25 Island anoxic events by Aug. 27, up from 16 in 2011.

Two weeks ago, Hal Perry, the Opposition's environment critic, called on the provincial government to do something to prevent Island waterways from becoming anoxic.

Perry criticized the government for cancelling a pilot project on sea lettuce harvesting and said the government needs to work with local watershed groups to come up with a solution.

A 2008 joint federal-provincial commission identified fertilizers applied to farms and golf courses, along with septic systems and other human development along rivers, as major sources of the problem, which it said will take decades to fix.