AIM has years of experience with benthic mats. More recently we have been removing old mats that have been on the bottom for too long. As a management technique we view the use of mats as a quick solution for small, dense beds of milfoil that are feeding fragments into a water body. As an overall management technique it is far less effective than hand-harvesting.
When a benthic mat is placed on the bottom it creates a dead zone in terms of plant life. Without the re-growth of native plants there is no structure habitat for
bait fish and game fish. With hand-harvesting, the beneficial plants are left to grow while invasive growth is removed, allowing for minimal impact on the existing fishery and overall ecosystem.
We have also observed that benthic mats collect silt on their surfaces over time. That silt then provides growth medium for more milfoil. On Lake George we hand-harvested dense milfoil beds that had benthic mat material underneath them.
Mats are a quick fix for a small, yet dense bed that is spreading milfoil via fragmentation.