Two water management districts and various organizations maintain Lagoon information.
To learn more about the Lagoon, please visit these websites:

St John's River Water Management District
http://www.sjrwmd.com/indianriverlagoon/index.html

US Environmental Protection Agency
http://www.epa.gov/owow/estuaries/programs/irl.htm

Manatee Observation and Education Center
http://www.manateecenter.com

Smithsonian Marine Center at Fort Pierce
http://www.sms.si.edu/irLspec/index.htm

Florida Oceanographic Society
http://www.floridaoceanographic.org

America's National Wildlife Refuge Service
http://www.fws.gov/refuges/

Florida Department of Environmental Protection
http://www.dep.state.fl.us/Parks/

Florida's Aquatic Preserves
http://www.dep.state.fl.us/coastal/programs/aquatic.htm

Marine Resources Council
http://www.mrcirl.org

Oxbow Eco-Center
http://www.stlucieco.gov/erd/oxbow/

Environmental Learning Center
http://www.elcweb.org