While prevention is the first line of defense, even the best prevention efforts will not stop all invasive species. Early detection and rapid response (EDRR) efforts increase the likelihood that invasions will be halted and eradicated. Once a species becomes widely established, the only action possible is the partial mitigation of negative impacts.

Based on the work of the ISAC/NISC EDRR Subcommittee, NISC has approved Guidelines for Early Detection and Rapid Response. Many states and some regions of the U.S. have developed their own EDRR tolls (see the Aquatic Nuisance Task Force sites.)

EDDR actions are grouped into three (3) main categories: