Complex sentence: Glacier Northwest has agreed to expand this dock to distances that reduce the risk of damaging the local habitat, yet many concerns still remain, including the potential damage to the local eelgrass habitat, a vital part of the salmon's livelihood.
Split into simpler sentences: Glacier Northwest has agreed to expand this dock to distances that reduce the risk of damaging the local habitat, yet many concerns still remain. One of the biggest concerns is the potential damage to local eelgrass habitat--a vital part of the salmon's livelihood.