Native to Chesapeake Bay
- Family - Zosteraceae
- Distribution - Eelgrass is one of the most abundant and
most persistent bay grass species in the high-salinity portions of Chesapeake Bay and
the lower tributaries. Most eelgrass is found from the Choptank River south to
the mouth of the Bay. Small isolated populations have also been found in Eastern
- Recognition - Eelgrass has a thick creeping rhizome 2 to
5 mm (1/16 in to 1/8 in) with numerous roots and a leaf at nodes spaced 1 to 3.5
cm (1/3 in to 1 ˝ in) apart. Alternate, ribbon-like leaves with rounded tips
arise from these nodes and grow to 1.2 m (4 ft) in length and 2 to 12 mm (1/16
in to 1/3 in) width. Each leaf has a tubular, membranous basal sheath 5 to 20 cm
(2 in to 8 in) long and with a width greater than that of the leaf itself. The
leaves are relatively small and narrow where the plants grow on shallow, sandy,
physically exposed substrates. Longer, wider leaves occur on plants growing on
deep, muddy, and exposed areas.
- Ecological Significance - Eelgrass is the only true “seagrass”
found in the Chesapeake Bay. Eelgrass occurs along both coasts of the United
States, and the Chesapeake Bay is near the southern limit of its distribution on
the east coast. Unlike, other bay grasses, eelgrass dies back during the warm
summer months and grows best in the cooler waters of spring and fall. Eelgrass
is important habitat for blue crabs that use the beds for protective cover
during mating and as juveniles. It is also the important habitat for the
pipefish and speckled sea trout, and important food source for brant
geese (which almost disappeared when the eelgrass declined significantly in the
1930's due to the “wasting disease”),
widgeon, redhead and
black ducks and
green sea turtles.
- Similar Species - Wild celery (Vallisneria
americana) has an appearance similar to that of eelgrass but is
distinguished on the basis of its leaves, which have a light green strip down
the middle and are broader than those of eelgrass. Because wild celery prefers
lower salinity and eelgrass higher salinity, the two species are not known to
occur in the same location although their salinity ranges overlap slightly.
- Reproduction - Eelgrass reproduces asexually and sexually.
Asexual reproduction occurs through growth and elongation of the rhizome and by
formation of turions. Sexual reproduction occurs through seed formation, and
begins with flowering in May and June. Eelgrass is monoecious and fertilization
occurs by drifting pollen. Male and female flowers mature at different times on
the same plant to prevent self-fertilization. Once fertilized the flowers
develop into seed-bearing generative shoots that eventually break off and float
to the surface. The shoots then release their seeds as they drift.
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