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Description
Synonymy - An unattached form has been often distinguished from the attached form as separate species ( 'scorpioides' or 'mackaii') (e.g. Taylor 1957) or as a variety or ecotype ('forma'; 'ecad', etc.) (South and Hill 1970; Chock and Mathieson 1979). These forms tend to have flattened and very dichotomous (branched) thalli, and tend to lack air bladders and receptacles (sexual organs) (Gibb 1957; South and Hill 1970). The 'ecad' or ecotype interpretation seems to be more common in recent literature (e.g. Chock and Mathieson 1979). Gradients among morphotypes occur in marshes (Brinkhuis 1976; Chock and Mathieson 1976), and frond fragments from the ' scopiodes' ecad will take on the morphology of the drifting 'mackai' ecad when transplanted to the lower intertidal (Brinkhuis and Jones 1976). The frequency of sexual reproduction is greatly reduced in these forms, but a portion of the sexual offspring produced are attached. Most records in the Chesapeake region are either of drifting plants or plants washed ashore (Humm 1979; Orris 1980; Zaneveld and Willis 1976), but attached plants are known from Ocean City MD (Ott 1973) and NC (Schneider and Searles 1991; Searles 1997 personal communication; Zaneveld and Willis 1976). In addition to this distinction, additional morphological differentiation probably exists. 'There can be no doubt that genetically differentiated races of Ascophyllum exist, and in large numbers' (Baardseth 1970).
Taxonomy
| Kingdom | Phylum | Class | Order | Family | Genus |
|---|---|---|---|---|---|
| Protista | Phaeophyta | Phaeophyceae | Fucales | Fucaceae | Ascophyllum |
Synonyms
Invasion History
Chesapeake Bay Status
| First Record | Population | Range | Introduction | Residency | Source Region | Native Region | Vectors |
|---|---|---|---|---|---|---|---|
| 1946 | Unknown | Stable | Native & Introduced | Regular Resident | Western Atlantic | AmphiAtlantic | Fisheries(Packing Material-Bait) |
History of Spread
Ascophyllum nodosum is a seaweed found on both coasts of the North Atlantic. Attached plants occur regularly on rocky shores from Portugal to the White Sea in Europe, on the coasts of Iceland and Greenland, and from Baffin Island to DE (Baardseth 1970; South and Tittley 1986; Taylor 1957; Zaneveld 1972). This species also occurs in unattached form, entangled among marsh vegetation, lying on mudflats, or freely drifting at the ocean surface ('ecad' or var. scorpioides or mackai). Unattached A. nodosum have been collected in the eastern Atlantic off the coast of Ghana just south of the equator, probably derived from western European populations (John 1974). Most reports of A. nodosum from the Chesapeake Bay region are of unattached plants (Humm 1979; Zaneveld and Willis 1976).
Ascophyllum nodosum is widely used as a packing material for baitworms shipped from the Maritime provinces of Canada and New England. The seaweed is commonly dumped on the shore or water by fisherman (Cohen and Carlton 1995; Orris 1970). This is the probable mechanism for introduction of the seaweed to upper Chesapeake Bay (Orris 1980), and Hood Canal WA (Pacific), and a potential source for introductions to other locations, especially on the Pacific coast (Cohen and Carlton 1995). Living populations have been found in San Francisco Bay, and in at least once case, successfully eradicated (Miller et al. 2002).
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.
Chesapeake records are summarized below:
Atlantic Coast - Ocean City MD, 'attached to the North Jetty', and 'abundant in the wash' (forma scorpioides), 1971 (Ott 1973); Assateague MD, 1955 (Zaneveld and Willis 1976); Chincoteague Inlet VA (Ott 1973); (Northampton County VA (near Hog Island), 1960; Fisherman's Island 1962; 'Seaside Park',Virginia Beach VA, 1946 (Zaneveld and Willis 1976). These records probably represent both introduced and naturally dispersed plants.
Lower Bay - Norfolk VA, 1962 (Zaneveld and Willis 1976); Pocomoke Sound MD (Krauss et al. 1971). These records probably represent both introduced and naturally dispersed plants.
Upper Bay - Patuxent River estuary, drifting (Anderson et al. 1968); Baltimore County MD, 1960, drifting; Sandy Point State Park (Anne Arundel County) MD, 1955, drifting (Zaneveld and Willis 1976).
West Coast- In San Francisco Bay, floating bunches of Ascophyllum nodosum have frequently been found (Miller 1969), usually of the attached form of the plant, A. nodosum ecad .scorpiodes, and often in deteriorating condition. In September 2002, a small patch of healthy A. nodosum was discovered during a survey of San Francisco Bay, near the Redwood City marina on South San Francisco Bay. The form of A. nodosum was ecad mackayi, a growth form which grows entwined around salt-marsh vegetation. It was probably introduced with seaweed used to wrap bait-worms imported from New England or Atlantic Canada (Miller et al. 2005). The plants were eradicated by manual picking, and disposed in a landfill. No A. nodosum were seen at this site since December 2002. More recently, in 2008, growing A. nodosum was seen on the shores of Bay Farm Island, Alameda CA. Ateempts at removal have been made, but whether it has been eradicated is unknown (Whitman Miller, personal communication). Ascophyllum nodosum has also been seen in Hood Canal, Puget Sound, but the establishment of this seaweed there is unknown (Linda Goff, personal communication, cited by Cohen and Carlton 1995.)
History References - Anderson et al. 1968; Baardseth 1970; Cohen and Carlton 1995; Humm 1979; John 1974; Krauss et al. 1971; Miller et al. 2002; Orris 1980; Ott 1973; Schneider and Searles 1991; South and Tittley 1986; Taylor 1957; Zaneveld 1972; Zaneveld and Willis 1976
Invasion Comments
Invasion Status - Ascophyllum nodosum occurs as both naturally occcuring plants (mostly along the Atlantic coast), and as introduced plants in bait packing material, which are probably dumped into waters throughout the region. Upper Bay occurrences are presumed to be exclusively due to introductions (Orris 1980), while lower Bay and coastal occurrences may consist of both introduced and naturally dispersed plants. Drifting A. nodosum can reproduce vegetatively, but seems to have only limited sexual reproduction (Chock and Mathieson 1979). 'It seems strange that in Virginia waters drifting plants do not produce viable embryos that would become attached, especially in the vicinity of Chincoteague Island (Humm 1979). In the upper Bay, A. nodosum is probably unable to reproduce at all, due to low salinities and high summer temperatures (Orris 1980).
Ecology
Environmental Tolerances
| For Survival | For Reproduction | |||
|---|---|---|---|---|
| Minimum | Maximum | Minimum | Maximum | |
| Temperature (ºC) | -1.8 | |||
| Salinity (‰) | 37.0 | 10.0 | 15.0 | 37.0 |
| Oxygen | ||||
| pH | ||||
| Salinity Range | meso-eu |
Age and Growth
| Male | Female | |
|---|---|---|
| Minimum Adult Size (mm) | ||
| Typical Adult Size (mm) | 450.0 | 450.0 |
| Maximum Adult Size (mm) | 3000.0 | 3000.0 |
| Maximum Longevity (yrs) | 13.0 | 13.0 |
| Typical Longevity (yrs |
Reproduction
| Start | Peak | End | |
|---|---|---|---|
| Reproductive Season | |||
| Typical Number of Young Per Reproductive Event |
|||
| Sexuality Mode(s) | |||
| Mode(s) of Asexual Reproduction |
|||
| Fertilization Type(s) | |||
| More than One Reproduction Event per Year |
|||
| Reproductive Startegy | |||
| Egg/Seed Form |
Impacts
Economic Impacts in Chesapeake Bay
Ascophyllum nodosum is apparently too rare in the Chesapeake region to have significant economic importance.
Economic Impacts Outside of Chesapeake Bay
Ascophyllum nodosum is extensively harvested in northern Europe, Atlantic Canada, and New England, for use in production of seaweed meal as a dietary supplement for livestock and also for alginate production (Baardseth 1970). This seaweed is also used as manure in some coastal areas (Baardseth 1970), and as packing material for bait and seafood (Orris 1980; Searles 1997).
Ecological Impacts on Chesapeake Native Species
Ascophyllum nodosum appears to be too rare in the Chesapeake region to have significant impacts on native biota. From NJ northwards, and on northern European coastlines, it is a very important component of the littoral seaweed community (Baardseth 1970; Taylor 1957). In those regions, its abundance is inversely correlated with the native seaweed Fucus vesiculosus, but this may be the consequence of differing habitat requirements as well as, or instead of competition (Baardseth 1970),
Ecological Impacts on Other Chesapeake Non-Native Species
Ascophyllum nodosum is probably too rare in the Chesapeake to have significant impacts on other introduced biota. In northern Europe, its abundance is inversely correlated with the introduced seaweed Codium fragile, but this may be a consequence of different habitat requirenebts, in addition to competition (Baardseth 1970).
References
Anderson, Richard D.; Brown, Russell, G.; Rappleye, Robert D. (1968) Water quality and plant distribution along the upper Patuxent River, Maryland, Chesapeake Science 9: 145-156Baardseth, B. (1970) Synopsis of biological data on knobbed wrack Ascophyllum nodosum (Linnaeus) Le Jolis, FAO Fisheries Synopsis 38: 1-40
Bold, Harold C.; Wynne, Michael J. (1978) Introduction to the Algae: Structure and Reproduction, , Englewood Cliffs, NJ. Pp.
Brinkhuis, I. H.; Jones, R. F. (1976) The ecology of temperate salt-marsh fucoids. In situ growth of transplant Ascophyllum nodosum ecads, Marine Biology 34: 339-348
Brinkhuis, J. H. (1976) The ecology of temperate salt-marsh fucoids. I. Occurrence and distribution of Ascophyllum nodosum ecads, Marine Biology 34: 325-338
Chock, J. S.; Mathieson, A. C. (1979) Physiological ecology of Ascophyllum nodosum (L.) Le Jolis and its detached ecad scorpioides (Hornemann) Hauck (Fucales, Phaeophyta), Botanica Marina 22: 21-26
Chock, Jay S. (1976) Ecological studies of the salt marsh ecad scorpioides (Hornemann) Hauck of Ascophyllum nodosum, (L.) Le Jolis, Journal of Marine Biology and Ecology 23: 171-190
Cohen, Andrew N.; Carlton, James T. (1995) Nonindigenous aquatic species in a United States estuary: a case study of the biological invasions of the San Francisco Bay and Delta, , Washington DC, Silver Spring MD.. Pp.
Humm, Harold J. (1979) The Marine Algae of Virginia, , Charlottesville. Pp.
John, David M. (1974) New records of Ascophyllum nodosum (L.) Le Jol. from the warmer parts of the Atlantic Ocean, Journal of Phycology 10: 243-244
Krauss, R.W.; Brown, R. G.; Rappleye, R. D.; Owens, A. B.; Shearer, C.; Hsiao, E.; Reveal, J. (1971) Checklist of plant species occurring within the hightide limits of the Chesapeake Bay, and its tributaries., , College Park, Maryland. Pp.
Orris, Patricia K. (1980) A revised species list and commentary on the macroalgae of the Chesapeake Bay in Maryland, Estuaries 3: 200-206
Ott, Franklyn D. (1973) The marine algae of Virginia and Maryland including the Chesapeake Bay area, Rhodora 75: 258-296
Peckol, Paulette; Harlin, Marilyn; Krumscheid, Priska (1988) Physiological and population ecology of intertidal and subtidal Ascophyllum nodosum (Phaeophyta), Journal of Phycology 24: 192-198
Schneider, Craig W.; Searles, Richard B. (1991) Seaweeds of the Southeastern United States, , Durham. Pp.
South, G. R.; Hill, R. D. (1970) Studies on marine algae of Newfoundland. I. Occurrence and distribution of free-living Ascophyllum nodosum in Newfoundland, Canadian Journal of Botany 48: 1697-1701
South, G. Robin; Tittley, Ian (1986) A checklist and distributional index of the benthic marine algae of the North Atlantic Ocean., , St. Andrews, New Brunswick, and London. Pp.
Taylor, William Randolph (1957) Marine Algae of the Northeastern Coast of North America, , Ann Arbor. Pp.
Zaneveld, Jacques S.; Willis, William M. (1976) Marine algae of the American coast between Cape May, N. J. and Cape Hatteras, N. C. III. The Phaeophycophyta, Botanica Marina 19: 33-46
Zaneveld, Jaques S. (1972) The benthic marine algae of Delaware, U.S.A., Chesapeake Science 13: 120-138