There are plenty of resources listed at the back of Whale in the Door. I will add more as I become aware of them.
Here are some of the organizations working to protect Atl’kitsem/Howe Sound. If you are concerned about the health of the Sound, I recommend you contact them and give your support:
Squamish Nation: http://www.squamish.net
Coastal Ocean Research Institute:
David Suzuki Foundation: https://davidsuzuki.org
Future of Howe Sound Society: http://futureofhowesound.org
My Sea to Sky: http://www.myseatosky.org
Concerned Citizens Bowen: http://ccbowen.ca