A Ten-year Study of Meroplankton in North Carolina Estuaries: Mysid shrimps

Seven species of mysid shrimps taken in semiquantitative, nocturnal, surface plankton samples showed variable levels of abundance and frequency of occurrence from stations near the sea to the head of estuaries in North Carolina. Bowmaniella dissimilis occurred mainly in samples from stations near the sea in every month of the year, and reached its greatest abundance from spring through autumn coincident with its breeding season. B. johnsoni was taken at stations near the sea only twice. Mysidopsis bigelowi, the second most abundant species, occurred in samples from every station, and was in breeding condition throught the estuaries from late winter to mid-autumn. Metamysidopsis mexicana occurred sporadically in samples from 3 stations near inlets, was in breeding condition throughout the year, but appeared to be abundant in summer and fall. Promysis atlantica appeared infrequently at stations near inlets in all months except Feb. and Mar., usually in breeding condition. Neomysis americana was the most abundant species, reaching its greatest concentration in samples from middle to upper estuarine stations where spawners were almost always present. Size differentials suggested more than a single generation per year. The species showed no evidence of nocturnal stratification in the shallow 6-m deep estuarine water. Heteromysis formosa occurred sporadically from May to Dec.