Invasion History

First Non-native North American Tidal Record: 1960
First Non-native West Coast Tidal Record: 1960
First Non-native East/Gulf Coast Tidal Record:

General Invasion History:

Sabaco elongatus is a marine tube-dwelling maldanid polychaete, whose native range is from the southern Gulf of St. Lawrence to Belize (Hughes and Thomas 1971; Light 1974). It has been introduced and is well-established in San Francisco Bay, California (Light 1974), and has been reported from Bodega Bay (Schneider et al. 2007) and Port Hueneme (Fairey et al. 2007).

North American Invasion History:

Invasion History on the West Coast:

Sabaco elongatus was first collected from South San Francisco Bay, California (CA) in 1960. It is well-established and widespread in subtidal soft sediments in the Bay, from Carquinez Straits and San-Pablo Bay to the Central and South Bays, over a salinity range of 7-23+ PSU. It is now one of the dominant benthic infaunal species in San Francisco Bay, especially in the South and Central Bays, where it occurs at densities of 1,000 to 5,000 m-3 (Light 1974; Cohen and Carlton 1995; Topping et al. 2004; Gillett et al. 2014). Transplants of Eastern Oysters were considered to be a likely vector of introduction (Light 1974). Ballast water transport is also possible. However, its mode of development has not been described, and some other Maldanidae (Clymenella torquata; Micromaldane spp.) are known to have benthic larvae (Mead 1897; Newell 1951; Rouse 1991), making ballast water transport less likely. Sabaco elongatus has been included in species lists for Port Hueneme (Fairey et al. 2002) and Bodega Bay, CA (Schneider et al. 2007), but no details are available.


Sabaco elongatus is a marine tube-dwelling maldanid polychaete. Its body is slender and resembles a stick of bamboo, with elongated body segments and poorly defined parapodia. The body consists of 22 segments, including a fused prostomium and peristomium, another segment lacking chaetae, 19 chaetigers, and a funnel-like pygidium. The pre-anal segments have setae. The position of the animal is head-down in its tube, with the pygidium protruding (Light 1974; Lippson and Lippson 1997; California Academy of Sciences 2002).

Its head is pointed, with the prostomium forming an upward-turned prow, in a lateral view. The lateral cephalic lobes are separated from the posterior lobe by deep lateral notches. The margin of the cephalic plate has a smooth edge, with an upward-turned lip. The head is nearly semi-circular in a dorsal view. The mouth is ventral. The paired nuchal organs are broad and parallel, but do not touch the margin of the cephalic plate. The post-cephalic segment (lacking chaetae) and the first three chaetigers are completely biannulate (separated by double rings), while the next 3-4 chaetigers are incompletely biannulate. The first chaetiger is rolled up over the posterior edge of the post-cephalic, non-chaetigerous segment. The tori (bases of the parapodia) form prominent lumps in each chaetiger. The segments gradually become longer in the posterior direction. From segments 6-14 posteriorly, there are folds of tissue (epaulettes) behind the chaetae at segmental nodes. The pygidium is funnel or trumpet-like, with the dorsal lobe flared outward and separated from the ventral lobe by a deep notch (Light 1974; Lippson and Lippson 1997). San Francisco Bay specimens ranged from 62 to 215 mm, while Atlantic specimens are typically 150-300 mm and sometimes reach 450 mm (Light 1974). The color is variable, from yellow-brown, flesh-brown, pink, reddish brown, chocolate brown or dark-gray, but usually with darker colors (bluish, purplish, blackish) and an iridescent sheen anteriorly (Light 1974; California Academy of Sciences 2002). The tube is long and thick, composed of black mud and clay, often sand-encrusted (Light 1974; Lippson and Lippson 1997).


Taxonomic Tree

Kingdom:   Animalia
Phylum:   Annelida
Class:   Polychaeta
Subclass:   Scolecida
Family:   Maldanidae
Genus:   Sabaco
Species:   elongatus


Asychis amphiglypta (Ehlers, 1897)
Brachioasychis americana (Hartman, 1945)
Brachioasychis colmani (Monro, 1939)
Maldane elongata (Verrill, 1873)
Maldanopsis elongata (Verrill, 1873)
Sabaco elongatus (None, None)
Asychis elongatus (None, None)

Potentially Misidentified Species



Sabaco elongatus is a marine tube-dwelling maldanid polychaete. The life history and reproduction of this polychaete has not been studied, either in its native range or in San Francisco Bay. However, in other polychaetes (Clymenella torquata; Micromaldane spp., Axiothella rubrocinta species complex) of this family, sexes are separate, and larvae are demersal, brooded in the female's tube or developed externally. The larvae begin feeding on benthic diatoms and undergo a gradual metamorphosis, thereby adopting a head-down posture, constructing a tube, and developing an adult pygidium (Mead 1897; Newell 1951; Wilson 1983; Rouse 1991).

Sabaco elongatus is a head-down deposit feeder, living in a vertical tube composed of mud, sand, and clay, up to 600 mm long, protruding from the sediment (Lippson and Lippson 1997). In San Francisco Bay, it was collected at temperatures of 11-14°C and salinities of 7-23 PSU (Light 1974). In its wide native range, from the Gulf of St. Lawrence to Belize, it tolerates a range of temperatures from cold-temperate to tropical. Unlike its relative Clymenella torquata, it does not occur in intertidal environments and is usually found in the deeper waters of estuaries. For instance, it is found at 11-17 m in San Francisco Bay (Light 1974) and at 7.6 to 27 m in Chesapeake Bay (Wass 1972). It occurs in fine sands mixed with silt-clay or pure silt (Wass 1972; Light 1974). This worm feeds by ingesting detritus buried in the sediment and then excreting sediment and undigested detritus on to the sediment surface (Lippson and Lippson 1971). Potential predators include fishes and crabs.



Trophic Status:

Deposit Feeder



General HabitatUnstructured BottomNone
General HabitatOyster ReefNone
Salinity RangeMesohaline5-18 PSU
Salinity RangePolyhaline18-30 PSU
Salinity RangeEuhaline30-40 PSU
Tidal RangeSubtidalNone
Vertical HabitatEndobenthicNone

Tolerances and Life History Parameters

Minimum Salinity (‰)7Field record, San Francisco Bay (Light 1974)
Maximum Salinity (‰)35Typical Atlantic marine salinity
Minimum Length (mm)62Light 1974
Maximum Length (mm)450Light 1974
Broad Temperature RangeNoneCold temperature-Warm temperate
Broad Salinity RangeNoneMesohaline-Euhaline

General Impacts

Sabaco elongatus has become one of the most abundant infaunal invertebrates in San Francisco Bay (Cohen and Carlton 1995). As a long, head-down deposit feeder, it transports sediment and detritus to the surface, potentially altering sediment qualities and transporting buried contaminants to the surface. It can also be considered a sediment stabilizer and it has obvious effects on surface microtopography and burial of surface materials as eelgrass seed or organic matter (Levin et al. 1997; Luckenbach and Orth 1999). However, to our knowledge, these impacts have not been studied for this species. They are well known for other maldanid polychaetes. 

Regional Distribution Map

Bioregion Region Name Year Invasion Status Population Status
NA-ET2 Bay of Fundy to Cape Cod 0 Native Estab
NA-ET3 Cape Cod to Cape Hatteras 0 Native Estab
CAR-VII Cape Hatteras to Mid-East Florida 0 Native Estab
CAR-I Northern Yucatan, Gulf of Mexico, Florida Straits, to Middle Eastern Florida 0 Native Estab
CAR-II None 0 Native Estab
NEP-V Northern California to Mid Channel Islands 1960 Def Estab
NEP-VI Pt. Conception to Southern Baja California 2001 Def Unk
P090 San Francisco Bay 1960 Def Estab
P062 _CDA_P062 (Calleguas) 2001 Def Unk
P093 _CDA_P093 (San Pablo Bay) 1960 Def Estab
P112 _CDA_P112 (Bodega Bay) 0 Def Unk
NA-S3 None 0 Native Estab
S030 Bogue Sound 0 Native Estab
M128 _CDA_M128 (Eastern Lower Delmarva) 0 Native Estab
M020 Narragansett Bay 0 Native Estab
G160 East Mississippi Sound 0 Native Estab
G100 Apalachicola Bay 0 Native Estab
G070 Tampa Bay 0 Native Estab
S206 _CDA_S206 (Vero Beach) 0 Native Estab
M130 Chesapeake Bay 0 Native Estab
M010 Buzzards Bay 0 Native Estab
N040 Blue Hill Bay 0 Native Estab
G170 West Mississippi Sound 0 Native Estab
S045 _CDA_S045 (New) 0 Native Estab
G300 Aransas Bay 0 Native Estab
M040 Long Island Sound 0 Native Estab
P286 _CDA_P286 (Crescent-Hoko) 1999 Def Unk
NEP-III Alaskan panhandle to N. of Puget Sound 1999 Def Unk
P270 Willapa Bay 1999 Def Unk
NEP-IV Puget Sound to Northern California 1999 Def Unk

Occurrence Map

OCC_ID Author Year Date Locality Status Latitude Longitude


California Academy of Sciences 2002 <i>Sabaco elongatus</i> (Verrill, 1873). <missing URL>

Carlton, James T. (1979) History, biogeography, and ecology of the introduced marine and estuarine invertebrates of the Pacific Coast of North America., Ph.D. dissertation, University of California, Davis. Pp. 1-904

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, U.S. Fish and Wildlife Service and National Sea Grant College Program (Connecticut Sea Grant), Washington DC, Silver Spring MD.. Pp. <missing location>

Fairey, Russell; Dunn, Roslyn; Sigala, Marco; Oliver, John (2002) Introduced aquatic species in California's coastal waters: Final Report, California Department of Fish and Game, Sacramento. Pp. <missing location>

Gillett, David J.; Ranasinghe, J. Ananda; Stein, Eric D. (2012) <missing title>, San Francisco Estuary Institute, San Francisco CA. Pp. 1-19

Hartman, Olga (1944) New England Annelida. Part 2: Including the unpublished plates by Verrill with reconstructed captions, Bulletin of the American Museum of Natural History 82(7): 327-344

Holman, Luke E. de Bruyn, Mark Creer, Simon Carvalho, Gary Robidart, Julie; Rius, Marc (2019) Detection of introduced and resident marine species using environmental DNA metabarcoding of sediment and water, Scientific Reports 9: Published online

Hopkins, Dale R. (1986) Atlas of the distributions and abundances of common benthic species in San Francisco Bay, California, US Geological Survey Water Resources Investigations Report 86-4003: 1-16+ 25+228

Hughes, Roger N.; Thomas, Martin L. H. (1971) The classification and ordination of shallow-water benthic samples from Prince Edward Island, Canada, Journal of Experimental Marine Biology and Ecology 7: 1-39

Jimenez, H.; Ruiz, G. M. (2016) Contribution of non-native species to soft-sediment marine community structure of San Francisco Bay, California, Biological Invasions Publshed online: <missing location>

Levin, L.; Blair, N.; DeMaster, D.; Plaia, G.; Fornes, W.; Martin, C.; Thomas, C. (1997) Rapid subduction of organic matter by maldanid polychaetes on the North Carolina slope, Journal of Marine Research 55: 595-611

Light, William J. (1974) Occurrence of the Atlantic maldanid Asychis elongata (Annelida, Polychaeta) in San Francisco Bay, with comments on its synonymy, Proceedings of the Biological Society of Washington 87(17): 175-184

Lippson, Alice Jane; Lippson, Robert L. (1997) <missing title>, Johns Hopkins University Press, Baltimore. Pp. <missing location>

Luckenbach, Mark W.; Orth, Robert J. (1999) Effects of a deposit-feeding invertebrate on the entrapment of Zostera marina L. seeds, Aquatic Botany 62: 235-247

Mead, A. D. (1897) The early development of marine annelids, Journal of Morphology 13(2): 227-326

Newell, G. E. (1951) The life history of Clymenella torquata (Leidy). (Polychaeta), Proceedings of the Zoological Society of London 121(3): 561-586

Rouse, G. W. (1992) Oogenesis and larval development in Micoromaldane spp. (Polychaeta: Capitellida: Maldanidae), Invertebrate Reproduction and Development 21(3): 215-230

Schneider, David; Finity, Leah; Schneider, Reed (2007) <missing title>, Bodega Marine Reserve, Bodega Bay. Pp. <missing location>

Topping, Brent R. and 9 authors (2004) Sediment remobilization of mercury in South San Francisco Bay, California, US Geological Survey Scientific Investigations Report 2004-5196: 1-26

U.S. National Museum of Natural History 2002-2021 Invertebrate Zoology Collections Database.

Webster, H. E. (1879) Annelida chaetopoda of the Virginia coast, Transactions of the Albany Institution 9: 202-269

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

Wilson, W. H. (1983) Life-history evidence for sibling species in Axiothella rubrocincta (Polychaeta: Maldanidae), Marine Biology 76: 297-300

Yale Peabody Museum of Natural History 2008-2016 YPM Invertebrate Zoology - Online Catalog. <missing URL>