Eelgrass

Eelgrass (Zostera) is a type of bay and estuary-loving seaweed, once forming large beds of miniature forests in the San Francisco Bay adjacent to McLaughlin Eastshore State Park. Eelgrass beds are hotspots for biodiversity, as their ecosystem functions are numerous and important. Eelgrass is the most abundant primary producer in intertidal zones (the area of a seashore which is covered at high tide and uncovered at low tide). It provides energy for the entire ecosystem. Eelgrass beds also provide a place to “nurse” juvenile fish in a relatively protected environment compared to that of the open ocean.

Juvenile fish are easily consumed by predators, as they are slower moving and less able to distinguish between predator and friendly fish due to lack of experience. Eelgrass beds allow juveniles to grow in areas where shelter and an abundance of food is always available, increasing survival rates while facilitating population growth in a number of different species. Once numerous, there are few health eelgrass beds left in San Francisco Bay today due to portions of the bay having been filled in favor of urban development. Remaining eelgrass beds still support a rousing population of herring that likewise draw many predator species, making them crucial for this ecosystem to thrive.