Invasion

Invasion Description

1st Record: Sandy Point State Park (Anne Arundel County)/MD/Chesapeake Bay (1955, drifting, Zaneveld and Willis 1976). In the Chesapeake region and southward to Cape Hatteras, A. nodosum occurrences appear to consist both of naturally dispersed unattached plants, carried by the currents southward along the Atlantic coast (Humm 1979), and plants dispersed by human activities (Orris 1980; Searles 1997). Attached plants are known from Cape Hatteras (Schneider and Searles 1991; Zaneveld and Willis 1976) and probably occur in the Chesapeake region, but appear to be quite rare. ' A. nodosum has been found in the Bay but the meaning of its presence in the upper Bay is a subject for speculation and controversy. There are a dozen or more specimens in the herbarium (MARY) (=University of Maryland) or mentioned by Zaneveld and Willis (1976). These probably represent bait-packing material thrown overboard by fishermen rather than an endemic population of A. nodosum in the upper Bay. Several facts and observations support this conclusion: (1) blood worms are shipped from MA to the Delmarva region packed in A. nodosum (2) specimens are usually found floating or washed ashore near popular fishing spots, i.e. bridges, state parks, and harbors, (3) I have seen fishermen throwing Ascophyllum overboard near the Chesapeake Bay bridge, and (4) I have never seen Ascophyllum in marshes along the upper Bay and its tributaries' (Orris 1980). Searles (1997) mentions lobsters as another commodity shipped in seaweed from New England which probably also contributes to records of A. nodosum around Cape Hatteras, and doubtless also in the Chesapeake region. The earliest published date for A. nodosum in the Chesapeake region is an herbarium specimen collected from Virginia Beach VA in 1946 (Zaneveld and Willis 1976), but that probably just reflects limited collecting activity in the region.

Geographic Extent

Introduced, establishment unknown: Baltimore County/MD/Chesapeake Bay (1960, drifting Zaneveld and Willis 1976); Sandy Point State Park (Anne Arundel County)/MD/Chesapeake Bay , (1955, drifting, Zaneveld and Willis 1976); MD/Patuxent River estuary, drifting (Anderson et al. 1968). Probably native or naturally dispersed: Norfolk/VA/Hampton Roads (1962, Zaneveld and Willis 1976); MD/Pocomoke Sound (Krauss et al. 1971).