Lake Ontario Waterkeeper


Mark Mattson
[email protected]
(416) 861-1237

Lake Ontario’s name comes from the Iroquoian language and means “lake of shining waters.” The First Nations were the first to live in the watershed, arriving some 7,000 years ago. Today, Lake Ontario is home - and a source of drinking water - to 9-million people living in Ontario, Canada and New York State, USA. Because of the size of the lake and its connection to the Atlantic Ocean, Lake Ontario is an ecological wonder. Fish travel back and forth from the ocean to the freshwater lake. Different parts of the lake offer different habitats, ranging from dunes to wetlands to forest to rocky cliffs. Because of human activities, at least 10 species of fish have gone extinct and at least 15 exotic species have been introduced in the last 200 years.

Mark Mattson is a prominent environmental lawyer who has spent the last decade building a network of successful community-focused environmental organizations across Canada. His love of water stems from his childhood summers swimming and fishing on Wolfe Island, near Kingston. Born into a family of lawyers in Southern Ontario, Mark grew up with a passion for fairness and individual rights. He has worked in the private, public, and nonprofit sectors over the course of his career. As a prosecutor, first for government and then for NGOs, Mark was part of ground- breaking private prosecutions and administrative cases against major industrial polluters. After ten years in the courtroom, Mark founded Lake Ontario Waterkeeper in 2001 and remains the organization’s full-time Waterkeeper and President to this day. Mark sits on the board of directors of four Waterkeeper organizations in the U.S. and Canada.


379 Adelaide Street West (Basement, west side)
Toronto, Ontario M5V 1S4