Founder and President

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 began to devote more time to developing institutions that will restore and protect watersheds for generations to come. He 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.

When he transitioned from full-time lawyer to full-time Waterkeeper more than ten years ago, Mark was able to unite his commitment to social justice with his passion for water. He has spent the last decade working to uphold the ideal that each and every person has a right to swimmable, drinkable, fishable water.


Founder and Vice-President

Krystyn Tully has been organizing community events and organizations since her days as a high school student in Oshawa, Ontario. She helped Mark Mattson launch Lake Ontario Waterkeeper in 2001 and serves the organization to this day.

Over the course of the last decade, Tully helped to organize a wide range of fundraising events grantwriting campaigns that helped to raise $2-million for Waterkeeper’s work. She also spearheaded the creation of Swim Guide, a mobile app and website that connects people to clean, local beaches as well as Drink Guide, an app that documents drinking water advisories across Canada. These apps are now used by more than 100,000 people in Canada and the USA.

Since co-founding Lake Ontario Waterkeeper with Mark Mattson in 2001, Tully has written or edited more than 400 articles about water and environmental policy. She has appeared before numerous municipal, provincial, and federal government committees. For four years, she coordinated a mentoring program that connected aspiring lawyers with communities facing environmental challenges. For two years, she was editor and co-host of a weekly radio program. In 2012, she wrote a series of features on beaches for blogTO and became a regular contributor to Huffington Post.

Through Ryerson University’s part-time degree program, Tully has received extensive education in Public Administration and Governance, with a specialization in nonprofit sector management. She was profiled in NOW Magazine’s “Class Action” feature in October, 2012.



Events and Operations Manager

As Event and Operation Manager, Miriam works on planning fundraising and community events, and helps manage administrative duties. Miriam came to Canada as a young girl, forming a lasting bond with the urban natural spaces she grew up in. She completed a Bachelors degree in Environment and Resource Studies at the University of Waterloo in 2008 and a Masters in Environmental Studies at York University in 2011. She is passionate about social and environmental justice, and their intersections. Her research and past work experiences with community organizations in Toronto have revolved around understanding issues of diversity and inclusion in the context of environmental movements. She loves the outdoors, hiking, and the chance to go fishing – especially when it involves a shore lunch!



Technical Advisor

Dylan is the in-house technical advisor to Lake Ontario Waterkeeper, dealing with information technology resources and technical projects. Dylan helped to build a variety of Lake Ontario Waterkeeper projects, including, Swim Drink Fish Music, and the Waterkeeper Swim Guide. 

Dylan has been working in the field of information technology for almost 20 years. He was the technology director of one of the GTA's early independent internet service providers and since 1998 has been the Chief Technology Officer of a successful e-commerce company.

Dylan is also Lake Ontario Waterkeeper's in-house photographer and videographer, as well as the pilot of our fleet of unmanned photography aircraft.


Communications Coordinator

As Lake Ontario Waterkeeper's Communications Coordinator, Ruby maintains our website, social media accounts, and e-mail newsletter. She creates and edits written and visual material to help people understand how, why, and what Waterkeeper is doing to create a swimmable, drinkable, fishable future.

Ruby is an experienced graphic designer who embraced digital media while working for Patagonia Toronto. Inspired by Patagonia’s philosophies and business practices, Ruby started directing her media skills towards environmental causes. She started working at Waterkeeper full-time in August, 2014.

Ruby is always looking for different ways to tell stories through words, images, video, and audio so send her a message or, reach her through our social media channels: TwitterFacebook, and Instagram.



Swim Guide Affiliates Coordinator

As Swim Guide Affiliates Coordinator, Gabrielle supports the public and nonprofit organizations that contribute water quality information to the Waterkeeper Swim Guide app and website. Gabrielle also monitors information for 5,000 beaches in Canada, the US, and Mexico to ensure that Swim Guide users have access to up-to-the-minute water quality. 

Gabrielle joined LOW in 2014. She is a Southern Ontario native and grew up on the banks of the Welland Canal. She earned her undergraduate degree from Trent University in First Nations Studies and her Masters in Canadian History from Lakehead University. As part of her research she studied the environmental history of Aboriginal fisheries in Northwestern Ontario.  For the past three years, Gabrielle has volunteered at Israel’s Sea Turtle Rescue and Rehabilitation Centre. There she cared for sick and injured sea turtles, monitored sea turtle nests and hatchlings, and worked to promote the protection of the Mediterranean’s marine environment. 

Gabrielle is an avid open water swimmer and loves her native watershed.  


Office Assistant

As Office Assistant, Amy provides administrative assistance to our entire staff while keeping our office organized. She will be the first person to greet you when you call, visit, or email our Toronto office. Amy completed her bachelor’s degree in Music, Voice Performance along with a post-graduate diploma in Not-for-Profit management from the University of Western Ontario. She has worked in the non-profit sector for the past 5 years promoting cultural and community initiatives.

Amy has two passions – music and the environment. Growing up in the GTA, she spent many summers canoeing, sailing, and hiking around Lake Ontario. She is excited to join Lake Ontario Waterkeeper where she can combine her love for nature with her work in the public sector.