COLEMAN, P.E.I. -- The discovery of hundreds of dead fish in Prince Edward Island is spawning concerns from environmentalists about the use of pesticides in the province's agriculture industry.

Dale Cameron of Trout Unlimited says more than 2,000 fish have been scooped from a three-kilometre stretch of Barclay Brook in Coleman since Thursday following heavy rainfall.

Cameron, who discovered the fish kill, said that's more than triple the amount of fish that washed up on the same shores of the brook last July, though the current discovery is concentrated in a smaller area.

"This one looks worse," said Cameron.

He said he believes the actual number of dead fish is much higher, adding that predators and river currents would have quickly taken away the remains of other fish.

Rosanne MacFarlane, a freshwater biologist with the province, said an investigation is underway to determine the exact cause of the fish kill. But she said the water temperature and oxygen levels were within acceptable ranges and the fish looked healthy and well-fed.

"That leads one to believe that this was an acute toxic event, which we have seen in the past," said MacFarlane.

Provincial Green party Leader Sharon Labchuk said legislation that requires a 15-metre buffer zone between waterways and farm fields is not working.

She said pesticides should be eliminated from the province's agriculture industry altogether, as pesticide runoff has historically been a major cause of fish kills.

"There's a lot of support in P.E.I for a 100 per cent organic province," said Labchuk.

"There's a very strong sense in P.E.I. that the root cause of all this is industrial agriculture and that there are no ways that these kind of effects can be mitigated through ... (a piece) of new legislation."

Two years ago, trout and other fish were found dead over a two-kilometre section of the Montrose River after heavy rainfalls.

In July 2007, investigators suggested that pesticides from farmers' fields had killed thousands of fish that were found floating in the Dunk and Tryon Rivers in western P.E.I.

Labchuk said she's concerned that fish kills are becoming accepted as normal.

"The concern is that this has been going on for decades, and it's just, 'Ho hum, that's the way that it is in P.E.I.,"' she said.

"People are at a loss as to how they can influence government to make it stop."

Gretchen Fitzgerald of Sierra Club Canada agrees with Labchuk, saying that the use of pesticides should at least be reduced and the province should better enforce buffer zone regulations.

Environment Minister Janice Sherry said last year's fish kill prompted the provincial government to draft changes to regulations that she hopes will be introduced in the legislature this fall.

"My department has certainly been working diligently to look at all areas, the grass headlands and the buffer zones," Sherry said.

She said the department has been working with the P.E.I Potato Board and other agricultural bodies over the past year to get feedback.

"There's a more open willingness to work together in moving forward and finding solutions that are positive and effective for our agriculture community because, let's face it, it's the backbone of our economy," said Sherry.

"I see that as growth and I see that as something positive moving forward."