Many North Atlantic fish spend an important part of their life cycles in coastal eelgrass habitat, and eelgrass is declining. Eelgrass is a native submerged aquatic plant found in shallow waters from Nova Scotia to North Carolina’s Outer Banks. In the northern areas this hearty plant spends part of each year under sea ice. It is not a true grass, but a flowering plant that evolved from terrestrial flora. With thin, streamlined leaves, and an extensive root system, it is uniquely adapted to thrive in ocean tides and swell. What it isn’t adapted to deal with is nutrient pollution, dredging, and other anthropogenic stressors that have our productive eelgrass meadow areas on the decline.
Why does this matter to fish? Eelgrass is one of the most valuable habitats in the northeast. For example, in the early 1930s a “wasting disease” decimated 90% of the Atlantic eelgrass communities. This decline took a heavy toll on, among other things, bay scallops. Bay scallops are a commercially important shellfish that range from Cape Cod to Florida, and are very dependent on seagrass meadows. Not only do they attach to living eelgrass leaves after their larval stage, but they consume decaying leaves for a significant portion of their diet. Bay scallops declined dramatically throughout their range, coincident with the wasting disease, and populations didn’t begin to recover until the mid-1940s. Some populations, such as those in the Chesapeake Bay, have never come back. Lobsters, clams, and other invertebrates also declined.
Loss of eelgrass habitat has an effect on other commercial fishery species as well. Some of these animals, such as cod, winter flounder, and lobster use eelgrass meadows as a refuge in their early life stages. The eelgrass provides places to stay hidden, feeding opportunities, and shelter from wave energy. Some species, such as striped bass, bluefish, tautog, and fluke will use eelgrass habitat as adults, as a place to hunt and forage.
In addition to providing a place to eat and live, eelgrass is part of the foundation of our marine food web. Eelgrass is a primary producer – turning aquatic carbon dioxide into food and energy through photosynthesis; it is then eaten by many animals that are then consumed by our commercially important species. In short: eelgrass matters a lot to New England fishery resources, and its decline is not good news.
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