Invasion History

First Non-native North American Tidal Record: 1940
First Non-native West Coast Tidal Record: 1940
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

The infaunal polychaete Hobsonia florida was described from the Gulf Coast of Florida by Hartman (1951), and again, from Massachusetts, as Hypaniola grayi (Pettibone 1953). This worm is native to estuaries of the Atlantic and Gulf coasts of North America from Maine to Texas (Pettibone 1977), and has recently been reported from Venezuela (Díaz-Díaz and Liñero-Arana 2012). It has occurred on the West Coast, at least since the 1940s (Hobson and Banse 1981). Hobsonia florida is frequently found in brackish waters, and sometimes in fresh or nearly fresh tidal waters (Pettibone 1953; Banse 1979; Cohen et al. 2001).

North American Invasion History:

Invasion History on the West Coast:

Hobsonia florida was first reported from the West Coast by Banse (1979). However, it was abundant in preserved samples from Puget Sound, Washington (WA) collected as early as 1940 (Hobson and Banse 1981). Its introduced range currently spans from the Fraser River Delta, British Columbia (BC) (Banse 1979; Sewell 1996) to Coos Bay, Oregon (OR) (Fritz 2001). It is abundant at mudflat sites in the Fraser River Delta, BC; Skagit Bay, WA (Gallagher et al. 1983); Grays Harbor, WA (Banse 1979); Willapa Bay, WA (Cohen et al. 2001); the Columbia River estuary (Furota and Emmett 1993; Sytsma et al. 2004), Yaquina Bay, OR (Castillo et al. 2000) and a salt marsh in Coos Bay, OR (Fritz 2001). To our knowledge, H. florida has not been reported from California. The likeliest vector for transport is with Eastern Oysters (Crassotrea virginica) in the 19th and early 20th centuries. This polychaete is an infaunal tube-dweller, without a planktonic larva (Zottoli 1974), but ballast water transport might be possible if worms are swept up in suspended sediment.


Hobsonia florida is a small, tube-dwelling ampharetid polychaete, characteristic of soft sediments in brackish water. The worm is inflated anteriorly, tapered towards the posterior end, and terminates in a swollen anal knob (pygidium). The body wall is thick, and segmentation is prominent on the ventral side of the body, but on the dorsal side, the body wall is thin, and segments are poorly defined. The prostomium and segments 1-4, with branchiae (gills), constitute the head region. The thoracic region is about 2/3 of body length, and has weakly developed parapodia, with cylindrical notopodia bearing notochatae, starting on segment 3, and neuropodial uncini (rasp-lile chaetae) beginning on segment 6. There are 17 thoracic segments (starting with 3). The abdominal region consists of 28 segments, lacks notopodia, and has differently shaped uncini (Hartman 1951; Pettibone 1953; Banse 1981).

The prostomium is three-lobed and can be protruded forward to form a broad snout, with a central portion defined by two ridges. There are a pair of eyespots at the dorsal base of the prostomium. Posterior to the prostomium, the first (buccal) segment lacks chaetae. The mouth contains up to 20 pairs of oral tentacles, which can be extruded, or retracted completely. Segment 2 (paleal segment) forms a kind of collar, into which the buccal segment and prostomium can be partially retracted. There are four pairs of long, tapering branchiae (gills), on segments 2-5, with fan-shaped bundles of paleal chaetae at bases of the first pair of branchiae on segment 2. Segments 3-5 have short, cylindrical notopodia, with bundles of notochaetae, but neuropodial structures are absent (Hartman 1951; Pettibone 1953; Banse 1981).

Segment 6, and posterior thoracic segments bear both notopodia with chaetae, and neuropodial uncini, short paddle-like structures, bearing fine teeth. The abdominal segments lack notopodia, but have unicni which have a row of small teeth and a prominent cirrus, on the anterior segments. The cirri diminish posteriorly. The pygidium is slightly enlarged, and lacks anal cirri. Adult H. florida are 8-30 mm. Their color is greenish, with white spots. The worm lives in a 'rather straggly' tube composed of sand-grains and detritus, cemented with mucus, about five times the length of the animal, and with the top projecting above the bottom surface (Description from: Hartman 1951; Pettibone 1953; Zottoli 1974; Pettibone 1977; Banse 1981).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Annelida
Class:   Polychaeta
Subclass:   Palpata
Order:   Canalipalpata
Suborder:   Terebellida
Family:   Ampharetidae
Genus:   Hobsonia
Species:   florida


Amphicteis floridus (Hartman, 1951)
Amphicteis floridus gunneri (Hartman, 1951)
Hypaniola florida (Pettibone, 1977)
Hypaniola grayi (Pettibone, 1953)
Hobsonia florida (Banse, 1979)

Potentially Misidentified Species

Amphicteis gunneri
Hobsonia florida was originally treated as a subspecies of this cosmopolitan cold-water form (Hartman 1951).



Hobsonia florida is an ampharetid polychaete which dwells in a tube composed of mud, sand, and detritus, held together by mucus (Pettibone 1953). The tube is several times its body length. The upper third of the tube projects above the mud surface (Zottoli 1974). This worm is usually found in silty, brackish estuaries at salinities of 0-30 PSU (Pettibone 1953; Pettibone 1977). Sexes are separate. Eggs are laid inside the tube, and are apparently fertilized by sperm in incoming water (Zottoli 1974). The larvae develop inside the tube, passing through a trochophore stage, and start crawling outside the tube at the 3-chaetiger stage. Worms at this stage begin constructing their own tubes. Oral tentacles appear at the 8-chaetiger stage, while branchiae begin appearing at 11-chaetigers. Adults are mature at a length of about 8 mm (Zottoli 1974).

Based on its geographical range, this polychaete appears to tolerate a very wide range of temperature, from ice-covered winter conditions to tropical summers (Pettibone 1977; Díaz-Díaz and Liñero-Arana 2012). It is characteristic of brackish conditions within estuaries and can be found in mudflats, tide-pools, tidal ponds, saltmarshes, and eelgrass beds. Typical substrates include mud, sand, clay, and detritus (Pettibone 1953; Pettibone 1977; Gallagher 1983; Furota and Emmett 1993; Cohen et al. 2001). Hobsonia florida uses its tentacles to remove particles from the sediment surface (Fauchauld 1979). Likely predators include the burrowing sea anemone Nematostella vectensis (Zottoli 1974), crabs, shrimps, fishes, and birds, although Western Sandpipers (Calidris maurae) had no significant effect on their abundance (Sewell 1996).


Detritus, microalgae


fishes, shrimps, crabs, shorebirds

Trophic Status:

Deposit Feeder



General HabitatUnstructured BottomNone
General HabitatSalt-brackish marshNone
General HabitatGrass BedNone
Salinity RangeLimnetic0-0.5 PSU
Salinity RangeOligohaline0.5-5 PSU
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Tidal RangeLow IntertidalNone
Vertical HabitatEndobenthicNone

Tolerances and Life History Parameters

Minimum Temperature (ºC)0Based on geographical range
Minimum Salinity (‰)0Field record, Upper Palix river, Willapa Bay, WA (Cohen et al. 2010)
Maximum Salinity (‰)30Field salinity range, Wass 1972
Minimum Length (mm)8Pettibone 1953; Zottoli 1974; Pettibone 1977; Banse 1981
Maximum Length (mm)30Pettibone 1953; Zottoli 1974; Pettibone 1977; Banse 1981
Broad Temperature RangeNoneCold temperate-Warm temperate
Broad Salinity RangeNoneLimnetic-Polyhaline

General Impacts

Hobsonia florida is an abundant infaunal deposit-feeder in West Coast estuaries from Coos Bay, Oregon to the Fraser River estuary, British Columbia (Banse 1979; Fritz 2001). In the Columbia River estuary, it was ~10-50% of the benthic community by number, but only ~1-5% of the biomass (Furota and Emmett 1993). It probably plays an important role in the feeding of smaller organisms. However, in an enclosure experiment on the Fraser River delta, there was no significant feeding on this polychaete by Western Sandpipers (Calidris maurae) (Sewell 1996).

Ecological Impacts

Habitat Change - Hobsonia florida was one of several tube-building organisms which favored the recruitment of other tube-building organisms on the Skagit delta mudflats, Puget Sound. In experiments in which the density of H. florida was increased, the recruitment of the polychaete Manayunkia aestuarina and the tube-building crustacean Tanais sp. also increased, apparently due to physical effects of the worm tubes on water-flow, or organic deposition around the worm tubes (Gallagher et al. 1983).

Regional Impacts

NEP-IIIAlaskan panhandle to N. of Puget SoundEcological ImpactHabitat Change
The tube building polychaetes Hobsonia florida, Pseudopolydora kempi and taniads (Tanais) sp. (Crustacea, Peracarida) facilitate the recruitment of other taxa to 10 cm-2 azoic patches (Gallagher et al. 1983).
P290Puget SoundEcological ImpactHabitat Change
The tube building polychaetes Hobsonia florida, Pseudopolydora kempi and taniads (Tanais) sp. (Crustacea, Peracarida) facilitate the recruitment of other taxa to 10 cm-2 azoic patches (Gallagher et al. 1983).
WAWashingtonEcological ImpactHabitat Change
The tube building polychaetes Hobsonia florida, Pseudopolydora kempi and taniads (Tanais) sp. (Crustacea, Peracarida) facilitate the recruitment of other taxa to 10 cm-2 azoic patches (Gallagher et al. 1983).

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 0 Native Estab
NA-ET2 Bay of Fundy to Cape Cod 0 Native Estab
NA-ET3 Cape Cod to Cape Hatteras 0 Native Estab
NEP-IV Puget Sound to Northern California 1980 Def Estab
CAR-VII Cape Hatteras to Mid-East Florida 0 Native Estab
NEP-III Alaskan panhandle to N. of Puget Sound 1940 Def Estab
P270 Willapa Bay 2000 Def Estab
P280 Grays Harbor 1974 Def Estab
P260 Columbia River 1979 Def Estab
P170 Coos Bay 1998 Def Estab
P180 Umpqua River 1983 Def Estab
P210 Yaquina Bay 2000 Def Estab
P220 Siletz Bay 1979 Def Estab
P290 Puget Sound 1940 Def Estab
P240 Tillamook Bay 1996 Def Estab
CAR-III None 0 Crypto Estab
N195 _CDA_N195 (Cape Cod) 0 Native Estab
G056 _CDA_G056 (Sarasota Bay) 0 Native Estab
G090 Apalachee Bay 0 Native Estab
G100 Apalachicola Bay 0 Native Estab
N080 Sheepscot Bay 0 Native Estab
M010 Buzzards Bay 0 Native Estab
N185 _CDA_N185 (Cape Cod) 0 Native Estab
M060 Hudson River/Raritan Bay 0 Native Estab
N130 Great Bay 0 Native Estab
G250 Sabine Lake 0 Native Estab
M040 Long Island Sound 0 Native Estab
M100 Delaware Inland Bays 0 Native Estab
M110 Maryland Inland Bays 0 Native Estab
M130 Chesapeake Bay 0 Native Estab
S020 Pamlico Sound 0 Native Estab
S010 Albemarle Sound 0 Native Estab
S180 St. Johns River 0 Native Estab
G080 Suwannee River 0 Native Estab
G160 East Mississippi Sound 0 Native Estab
G260 Galveston Bay 0 Native Estab
P223 _CDA_P223 (Siltez-Yaquina) 1979 Def Estab
P286 _CDA_P286 (Crescent-Hoko) 1999 Def Estab

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


Banse, Karl (1979) Ampharetidae (Polychaeta) from British Columbia and Washington, Canadian Journal of Zoology 57: 1543-1552

Banse, Karl (1981) On some Cossuridae and Maldanidae (Polychaeta) from Washington and British Columbia., Canadian Journal of Fisheries and Aquatic Sciences 38: 633-637

Carlton, James T. (1989) <missing title>, <missing publisher>, <missing place>. Pp. <missing location>

Castillo, Gonzalo; Li, Hiram W.; Rossignol, Philippe (2000) Absence of overall feedback in a benthic estuarine community: a system potentially buffered from impacts of biological invasions., Estuaries 23(2): 275-291

Cohen, Andrew N. (2004) <missing title>, San Francisco Estuary Institute, San Francisco CA. Pp. 1-50

Cohen, Andrew N. and 22 authors (2001) <missing title>, Washington State Department of Natural Resources, Olympia. Pp. <missing location>

Cohen, Andrew; and 16 authors. (1998) <missing title>, Washington State Department of Natural Resources, Olympia, Washington. Pp. 1-37

Díaz-Díaz, Óscar; Liñero-Arana, Ildefonso L (2012) [Ampharetidae Malmgren, 1867 (Annelida: Polychaeta) of Venezuela], Boletín de Investigaciones Marinas y Costeras 41(1): 165-177

Díaz, Yusbelly J.; Guerra-García, José M.; Martína, Alberto (2005) Caprellids (Crustacea: Amphipoda: Caprellidae) from shallow waters of the Caribbean coast of Venezuela., Organisms, Diversity and Evolution Suppl. 10: 1-25

Fauchald, Kristian; Jumars, Peter A. (1979) The diet of worms : A study of polychaete feeding guilds, Oceanography and Marine Biology, an Annual Review 17: 193-284

Fritz, Gisela B. (2001) <missing title>, Humboldt State University, Arcata CA. Pp. 125

Furota, Toshi; Emmett, Robert L. (1993) Seasonal changes in the intertidal and subtidal macrobenthic invertebrate community structure in Baker Bay, lower Columbia River estuary, NOAA Technical Memorandum NMFS-NWFSC-5: 1-13

Gallagher, Eugene D.; Jumars, Peter A.; Trueblood, Dwight D. (1983) Facilitation of soft-bottom benthic succession by tube builders, Ecology 64(5): 1200-1216

Hartman, O. (1951) The littoral marine annelids of the Gulf of Mexico, Publications of the Institute of Marine Science 2(1): 7-124

Hentschel, Brian T. (1998) Intraspecific variations in 13C indicate ontogenetic diet changes in deposit-feeding polychaetes, Ecology 79(4): 1357-1370

Hobson, Katharine D., Banse, Karl (1981) Sedentariate and archiannelid polychaetes of British Columbia and Washington, Canadian Bulletin of Fisheries and Aquatic Sciences 209: 1-144

Jones, Kim Koch (1983) <missing title>, Oregon State University, Corvallis OR. Pp. 1-67

Olson, Mary Ann; Zajac, Roman N.; Russello, Michael A. (2009) Estuarine-scale genetic variation in the polychaete Hobsonia florida (Ampharetidae; Annelida) in Long Island Sound and relationships to Pleistocene glaciations, Biological Bulletin 217: 86-94

Pettibone, Marian H. (1953) A new species of polychaete worm of the family Ampahretidae from Massachusetts, Journal of the Washington Academy of Sciences 43(11): 384-386

Pettibone, Marian H. (1977) The synonymy and distribution of th4e estuarine Hypaniola florida (Hartman) from the East Coast of the United States (Polychaeta: Ampharetidae), Proceedings of the Biological Society of Washington 90(2): 205-208

Sewell, Mary A. (1996) Detection of the impact of predation by migratory shorebirds: An experimental test in the Fraser River estuary, British Columbia, Canada, Marine Ecology Progress Series 144: 23-40

Sytsma, Mark D.; Cordell, Jeffrey R.; Chapman, John W.; Draheim, Robyn, C. (2004) <missing title>, Center for Lakes and Reservoirs, Portland State University, Portland OR. Pp. <missing location>

Wilson, Sarah; Partridge, Valerie (2007) <missing title>, Washington State Department of Ecology, Olympia. Pp. 244

Wonham, Marjorie J.; Carlton, James T. (2005) Trends in marine biological invasions at local and regional scales: the Northeast Pacific Ocean as a model system, Biological Invasions 7: 369-392

Zottoli, Robert A. (1974) Reproduction and larval development of the ampharetid polychaete Amphicteis floridus, Transactions of the American Microscopical Society 93(1): 78-89