Wildlife officials don't know how the perch got into O'Keefe Lake. (Google Street View)

A P.E.I. lake, previously a popular trout fishing spot, is now swimming with white perch.

Provincial wildlife officials don't know how the perch got into O'Keefe Lake, but say they may have been introduced there by someone.

"While it's possible that they could have come up and into the lake, it's also possible that someone may have put them in intentionally or unintentionally," said fresh water fish biologist Roseanne MacFarlane.

"Fish like white perch get into a place where they're very happy, they're going to do well and their numbers are going to go up very quickly."

The lake used to be stocked regularly with trout for a recreational fishery, but that hasn't been done since mercury was found there five years ago.

The white perch are now adding to trouble at O'Keefe Lake, because the perch eat young trout. MacFarlane said if the province decides to restock the lake with trout again it will have to either remove all of the perch or bring in larger trout.