Seagrass beds provide vital habitat for both juvenile and adult fish and invertebrates, filter pollutants from the water, and stabilize bottom sediments. From 1950 to 1984, more than 40 percent of the bay's seagrasses disappeared, although improvements in water quality since then have allowed about 5,000 acres to return. This decision-making process also considers the duration of the downward trend. Declines that are observed for a long period of time may require more stringent actions than those observed for a short period, since short-term trends may be due to temporary influences such as weather patterns or localized spills. Turtle grass can live in many substrates, from mud to sand and broken shell, and tolerate a wide range of salinities, from 10 to 48 parts per thousand.
Turtle grass has long, leafy blades that usually occur in bundles of three to seven.
It is used by a variety of organisms, including more than 113 species of algae which attach to its leaves. For instance, the leaves of turtle grass are about of an inch wide, while those of shoal grass are less than a half-inch wide. And turtle grass may grow to 2 feet or more, while shoal grass tops out at about 15 inches. Although both types of grasses are often found together, shoal grass usually holds the distinction of being there first. For this reason, it is known as a pioneer species.