Sabaco elongatus

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:

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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.

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Description

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).

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Taxonomy

Ecology

General:

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.

Food:

Detritus

Trophic Status:

Deposit Feeder

DepFed

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Habitats

General Habitat	Unstructured Bottom	None
General Habitat	Oyster Reef	None
Salinity Range	Mesohaline	5-18 PSU
Salinity Range	Polyhaline	18-30 PSU
Salinity Range	Euhaline	30-40 PSU
Tidal Range	Subtidal	None
Vertical Habitat	Endobenthic	None

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Tolerances and Life History Parameters

Minimum Salinity (‰)	7	Field record, San Francisco Bay (Light 1974)
Maximum Salinity (‰)	35	Typical Atlantic marine salinity
Minimum Length (mm)	62	Light 1974
Maximum Length (mm)	450	Light 1974
Broad Temperature Range	None	Cold temperature-Warm temperate
Broad Salinity Range	None	Mesohaline-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. 

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References

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



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

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