The term "submerged aquatic vegetation" (SAV) for the purpose of this report encompasses twenty-three taxa from twelve vascular macrophyte families and three taxa from one freshwater macrophytic algal family, the Characeae. The term "SAV" in this report excludes all other algae, both benthic and planktonic, which occur in Chesapeake Bay, its tributaries, and the Delmarva Peninsula coastal bays. Although these other algae species constitute a portion of the SAV biomass in this region (Humm, 1979), this survey did not attempt to identify, delineate, or discuss the algal component of the vegetation nor its relative importance in the flora. The aerial survey cannot differentiate epiphytic algae on submersed vascular plants or differentiate many benthic marine algae species, including many macrophytes, which can co-occur in the same SAV beds.

Seventeen species of submerged aquatic vegetation are commonly found in Chesapeake Bay and its tributaries. Zostera marina (eelgrass), the only "true" seagrass species, can tolerate salinities as low as 10 ppt, and is dominant in the lower reaches of the bay. Myriophyllum spicatum (Eurasian watermilfoil), Stuckenia pectinata (sago pondweed), Potamogeton perfoliatus (redhead grass), Potamogeton crispus (Curly pondweed), Potamogeton pusillus (Slender pondweed), Zannichellia palustris (horned pondweed), Vallisneria americana (wild celery), Elodea canadensis (common elodea), Ceratophyllum demersum (coontail), Hydrilla verticillata (hydrilla), Heteranthera dubia (water stargrass), Najas guadalupensis (southern naiad), Najas minor, Najas gracillima,  and Najas sp. are freshwater species, some of which have the capacity to tolerate some level of salt, and are found in the middle and upper reaches of the bay (Stevenson and Confer, 1978; Orth et al., 1979; Orth and Moore, 1981, 1983; Moore et al., 2000). Ruppia maritima (widgeon grass) is tolerant of a wide range of salinities and is found from the bay mouth to the Susquehanna Flats. Approximately 9 other species are only occasionally found. When present, these less common species occur primarily in the middle and upper reaches of the bay and the tidal rivers. Of all species of SAV, the most abundant are Z. marina, R. maritima, V. americana, H. verticillata, P. perfoliatus, Stuckenia pectinata (P. pectinatus), and M. spicatum.

Zostera marina and R. maritima are the dominant SAV species found in the Delmarva Peninsula coastal bays.

An online key to Chesapeake Bay SAV is available from the Maryland Department of Natural Resources web page.