Freshwater bristleworm, Amphicteis invalida Grube, 1860, Hypania invalida occidentalis Ostroumouff, 1897, Phenacia oculata Schmankevitch, 1875

Nonindigenous Occurrences: The first nonindigenous occurrence of Hypania invalida was reported in Romania in the 1930s (Popescu-Marinescu 1992). It was stocked with 10 other macroinvertebrates in Lake Balkhash, Kazakhstan between 1953 and 1966 to strengthen forage base for commercial fish and has since naturalized and is present in the lake (Isbekov et al. 2019). It has undergone range expansion in the Volga basin following its intentional stocking there in the 1950s-1960s (Dzuban and Slobodchikov 1980) and is now present in the the Gorky, Cheboksary, Kuibyshev, Sratov, and Volgograd Reservoirs (Kurina and Seleznev 2019). It further extended its range westward, where it was found in the upper Danube in 1967 (Kothé 1968). After the opening of the Main-Danube canal in 1992, this species spread throughout the Main, Rhine, and Moselle River basins (Schmidt et al. 1998; Tittizer et al. 2000). In 1993, it was recorded in the Moskva River. It reached the Netherlands in 1995 (Klink and Bij de Vaate 1996) and now occurs throughout the entire Rhine basin (Bij de Vaate et al. 2002). In 2000, it was found far upstream in Belgian waters of the River Meuse (Bossche et al. 2001). Hypania invalida further spread to the Mittelland Canal in 2001 and is currently also found in the Marne and Seine River basins (Tittizer et al. 2000; Devin et al. 2006). Its most recent localities include the Oder-Spree Canal in 2006 (Müller et al. 2006), the Middle Elbe in 2007 (Eggers and Anlauf 2008), and the non-navigable waters of the Danube between Kelheim and Dillingen in 2008. It invaded the French Upper-Rhône River in 2007 (Besacier-Monbertrand et al. 2014). Established in Great Britain in 2008 (Gallardo and Aldridge 2015). Entered Szczecin Lagoon in 2010 (mouth of Odra River), shared by Poland and Germany (Oleneiin et al. 2016) and was later discovered in 2016 in the upper Odra River, Poland nearly 600 km upstream of the lagoon (Pabis et al. 2017). Found for the first time in Czech Republic in the Elbe River in 2014 likely spread by shipping and downstream dispersion (Straka et al. 2015). Widely distributed in Serbia and is found along the entire stretches of the Danube, Sava, and Tisa Rivers within the country (Zoric et al. 2020).

This species is eurytopic, found in rivers from rithron (upstream) to potamon (downstream) (Hörner et al. 2002). It tends to inhabit the eupotamon (true river channel) and avoid the plesiopotamon (disconnected side-arms with strong development of aquatic vegetation) (Sporka 1998; Krno et al. 1999). In multiple surveys, H. invalida was observed to co-occur with the Caspian mud shrimp, Chelicorophium curvispinum (Klink and Bij de Vaate 1996; Bossche et al. 2001). It is classified as an active filter feeder and deposit feeder (Manoleli 1975), consuming almost exclusively diatoms (Manoleli et al. 1974).

Hypania invalida reproduces sexually; males discharge sperm into the water column to fertilize eggs retained within the females’ dwelling tubes. Females typically carry between 50–250 eggs per clutch (Norf et al. 2010), though up to 970 eggs in a single female dwelling tube has been reported (Skal’skaya 2008). Mean egg size is 225 x 190 µm (Norf et al. 2010). This species is iteroparous (produces multiple generations per breeding season), with the potential for a single female to produce at least 1200 larvae in a lifetime. Offspring are brooded for about 2 weeks before they leave the parental dwelling tube and enter the water column. Larvae are <300µm when they colonize the sediment, reaching sexual maturity within 12 weeks after settlement. The ratio of females to males is typically 1:1, though following a population decline, females seem to become slightly more numerous than males. Additionally, females may grow larger and heavier than males (max ash-free dry mass- male: 0.10 g, female: 0.19 g). The maximum individual lifespan of H. invalida is roughly 10 months (Norf et al. 2010).

Potential pathway of introduction: Trans-oceanic shipping (ballast water)

This species is present throughout the North Sea basin (lower Rhine) and Baltic Sea basin (Grigorovich et al. 2003), both origins for high volumes of Great Lakes shipping traffic. Ricciardi and Rasmussen (1998) list H. invalida as the only Ponto-Caspian polychaete likely to be transported to the Great Lakes via ballast water. Submerged ship pumps have taken in larval specimens without being harmed; these worms then rapidly colonized every flume and bowl attached to the inward flow (Norf et al. 2010). With respect to the Great Lakes, however, Grigorovich et al. (2003) propose this species has a reduced probability of invasion due to the effects of ballast water exchange or flushing. The natural salinity range tolerated by H. invalida is 0–12 ppt (Mordukhai-Boltovskoi 1964). Therefore, current ballast water regulations (30 ppt flushing) are likely to be effective in reducing the probability of introduction to the Great Lakes. Additionally, Norf et al. (2010) hypothesize that the potential expansion of this species to the Great Lakes is likely to be hindered by ballast water exchange (Locke et al. 1993; Gray et al. 2007).

Hypania invalida has a moderate probability of establishment if introduced to the Great Lakes (Confidence level: High).

This species originates in the Ponto-Caspian, a region where climatic conditions are similar to those of the Great Lakes. Hypania invalida is able to survive in a wide range of temperature (2-25°C) and salinity (0–12 ppt) (Mordukhai-Boltovskoi 1964), both of which are well within the ranges that occur in the Great Lakes. Shorter ice cover duration and warmer water temperatures may also benefit this species by lengthening its suitable yearly spawning period; however, if water becomes too warm, this effect may be detrimental to survival. For instance, in the summer of 2003, when the lower Rhine experienced the highest water temperatures on record (27.8°C max) (Sprokkereef 2008), the population density of H. invalida was greatly reduced (Norf et al. 2010). Tolerance to other physiological factors is unknown or unreported, as is information on the mechanisms facilitating overwintering within this species’ native range (e.g., lower oxygen tolerance limit).
Hypania invalida prefers areas with soft substrate (e.g., silt, clay, fine sand) and current velocities less than 0.1 m/s (Norf et al. 2010; Zoric et al. 2011). These preferences make most of the Great Lakes basin suitable potential habitat with respect to water motion and bottom composition. Sandy bottoms covered with zebra mussel beds also serve as potential habitat, though settlement densities here are typically lower than those in soft-bottom communities (Norf et al. 2010; Yakovleva and Yakovleva 2010). This species is also able to live at a wide range of water depths (shoreline to 960 m) (Zenkevich 1963).

Hypania invalida is an active filter and deposit feeder, feeding primarily upon diatoms (Manoleli et al. 1974; Manoleli 1975). Hypania invalida also consumes the waste products of Dressenid mussels as food (Šporka and Nagy 1998; Kurina and Seleznev 2019). Hence, potential food items will likely not limit the distribution of this species within the Great Lakes and the presence of Dressenid mussels in the Great Lake may actually increase the likelihood for Hypania invalida to establish.

Hypania invalida has an extensive invasion history throughout Europe (Gherardi et al. 2009), with a spreading pattern that seems to suggest dispersal through a corridor connecting the Danube and Rhine rivers. Its dispersal pattern closely follows that of the European invasive isopod Jaera istri (Bij de Vaate et al. 2002). Panov et al. (2009) described this species as being at high risk for dispersal and establishment when introduced to a new area. Rapid expansion throughout European inland waterways has been facilitated by both human mediated (ballast water) upstream spread and natural (passive drift) downstream spread (Bij de Vaate 2003; Norf et al. 2010). Within a few years of introduction to the Rhine River, it had dispersed along the entire navigable river stretch (Bernauer and Jansen 2006) and into many adjacent waterways, including the Moselle (Devin et al. 2006) and Elbe Rivers (Eggers and Anlauf 2008).  It entered Szczecin Lagoon in 2010 (mouth of Odra River), shared by Poland and Germany (Oleneiin et al. 2016) and was later discovered in 2016 in the upper Odra River, Poland nearly 600 km upstream of the lagoon (Pabis et al. 2017). Despite its rapid and widespread expansion throughout Europe, little is known about its competitive abilities other than populations can quickly build up to high densities of >10,000 individuals/m2 (46,875 ind/m2 max reported) in favorable conditions (i.e., after the building of a dam) (Popescu-Marinescu 1992; Norf et al. 2010; Pavel et al. 2021). It was also the second most abundant alien species in the Saratov Reservoir, dominating the channel and floodplain habitat (Kurina 2017). In contrast, it was recently displaced from shallow habitats in the Caspian Sea (native range) due to the invasion of Streblospio gynobranchiata (Ghasemi et al. 2014).

Females have a high net fecundity due to frequent reproductive events (every 2 weeks) throughout maturity; it is estimated that a single female could produce at least 1200 larvae during her lifespan (Norf et al. 2010). Many of the sexual and reproductive traits of H. invalida (short generation time, external spermcast fertilization, existence of a dispersive larval phase, etc.) reflect attributes that are postulated to enhance the invasion success of aquatic invertebrates (Ricciardi and Rasmussen 1998; Bossche et al. 2001;  Bij de Vaate et al. 2002; Devin and Beisel 2007; Norf et al. 2010). The maternal care of offspring (brooding) by this species can additionally increase reproductive success by reducing larval mortality during early planktonic life stages (Schroeder and Hermans 1975). Increased knowledge of this species’ reproductive characteristics, has led Norf et al. (2010) to highlight the potential of H. invalida to invade the Great Lakes (contrary to earlier suggestions that it is unlikely to disperse internationally; Ricciardi and Rasmussen 1998).

Summary of species impacts derived from literature review. Click on an icon to find out more...

Environmental

There is little or no evidence to support that Hypania invalida has the potential for significant socio-economic impacts if introduced to the Great Lakes.

Panov et al. (2009) list H. invalida as a white-list species, meaning there is a low risk of it causing significant socio-economic impacts within introduced areas. There are currently no reports of significant socio-economic attributed to the presence of this species.

There is little or no evidence to support that Hypania invalida has the potential for significant beneficial effects if introduced to the Great Lakes.

Hypania invalida was intentionally introduced to areas of the Volga River in the 1950s-1960s to enhance the nutrition base for tank-raised fish (Dzuban and Slobodchikov 1980). However, this practice has not been repeated and there were no reports of significant benefits from the introductions.

*Ballast water regulations applicable to this species are currently in place to prevent the introduction of nonindigenous species to the Great Lakes via shipping. See Title 33: Code of Federal Regulations, Part 151, Subparts C and D (33 CFR 151 C) for the most recent federal ballast water regulations applying to the Great Lakes and Hudson River.

Note: Check federal, state/provincial, and local regulations for the most up-to-date information.

Control

Biological
There are no known biological control methods for this species.

Physical
There are no known physical control methods for this species

Chemical
There are no known chemical control methods for this species.

Note: Check state/provincial and local regulations for the most up-to-date information regarding permits for control methods. Follow all label instructions.