Where did eelgrass go?

While eelgrass habitat remains a prominent and abundant shallow water habitat, the abundance of eelgrass varied through time and is currently near all-time lows in certain areas of the northeast US. Eelgrass is impacted by natural and human-induced disturbances. The most profound natural disturbance affecting eelgrass abundance documented was the outbreak of wasting disease in the 1930s. Wasting disease is caused by a marine slime mold which infects eelgrass and can "thin" beds to the point of great vulnerability to storm damage or other environmental stresses or completely eliminate this seagrass species. The wasting disease outbreak in the 1930s is believed to have eliminated 90 percent of all eelgrass beds in the North Atlantic. Eelgrass beds began to recover in the mid 1940s throughout the Atlantic Ocean including Massachusetts and by the 1950s and 1960s it is believed eelgrass abundance was near pre-disease levels. The recovery was limited, however, due to a lack of a source for recolonization and human-induced degradation. Historic information indicates that eelgrass never recolonized in certain areas after the epidemic.

Wasting disease is still present. However, coastal and watershed development and physical disturbance are more widespread threats to eelgrass habitat. Areas that recovered from the wasting disease epidemic were dramatically reduced and degraded from a number of human-induced insults.

Balance Between Humans and Nature: Eelgrass