Limnoperna siamensis, Limnoperna lacustris

This species overwinters in South Korea, with water temperature as low as 0°C (Oliveira et al. 2010). In Japan, minimum temperature in a reservoir with mussels was 4.2°C (Nakano et al. 2011). Experimental research supports the 5°C threshold for prolonged exposure (Oliveira et al. 2010).

Consumes a variety of phytoplankton and zooplankton (Rojas Molina et al. 2010, Rojas Molina 2012, Frau et al. 2013). Adults do well despite low food availability (Oliveira et al. 2011).

Limnoperna fortunei can reach densities of 5000-250,000 individuals/m2 on hard substrate, and 90-2000 individuals/m2 on soft substrate (Frau et al. 2013).

Limnoperna fortunei negatively effects burrowing invertebrates and unionids (Karatayev et al. 2010) in South America, and may do the same in the Great Lakes given its high densities, such competitive exclusion is also seen in a similar species, D. polymorpha. L. fortunei modifies nutrient concentrations and proportions, and promotes aggregation of solitary Microcystis spp. cells into colonies; both these effects can favor blooms of this often noxious cyanobacteria (Cataldo et al. 2012).

Limnoperna fortunei negatively impacts zooplankton, and part of zooplankton decline may be due to starvation (i.e., mussel outcompetes zooplankton for food resources) (Rojas Molina 2012). Limnoperna fortunei has increased food availability in the benthic zone, which in part has increased invertebrate (excluding mussels) density 1.9 to 22 times and biomass 1.7 to 19 times (Burlakova et al. 2012). Limnoperna fortunei has homogenized benthic communities (Darrigran and Damborenea 2011, Sardiña et al. 2011); e.g., in one study 99.9% of community biomass consisted of the filtering collector trophic group (Burlakova et al. 2012). Limnoperna fortunei has shunted the dominant nutrient cycling from the pelagic to the benthic zone (Darrigran and Damborenea 2011, Cataldo et al. 2012, Rojas Molina 2012). Limnoperna fortunei has significantly reduced phytoplankton densities (>60%) and changed composition of the algae assemblages, most notably an increase in the flagellate group, relative to the diatom, single celled and colonial groups (Frau et al. 2013).

Limnoperna fortunei filters water substantially faster than D. polymorpha (Karatayev et al. 2010). Limnoperna fortunei brings increases in water transparency, and a decrease in suspended matter, chlorophyll a, and primary production (Boltovskoy et al. 2009). It also brings a decrease in turbidity and an increase in dissolved nitrogen in mussel presence (Rojas Molina 2012). Increased habitat complexity led to significant (e.g., threefold) increase in community taxonomic richness. Shells increase surface area for settling organisms, and also provide refuges from predation and physical stressors (Darrigran et al. 1998, Darrigran and Damborenea 2011, Burlakova et al. 2012, Spaccesi and Capitulo 2012). Transforms sand or mostly bare sediment into reef-like druses (Burlakova et al. 2012).

Potential pathway(s) of introduction: Transoceanic Shipping

Limnoperna fortunei has a high tolerance to fluctuating salinities; no significant mortality was observed in mussels exposed to a salinity cycle with abrupt salinity changes ranging 1–23% (mean 2.68%) over a month (Sylvester et al. 2013). This will affect probability of uptake (many ports located in estuarine environments with fluctuating salinity) and survival after ballast exchange (Sylvester et al. 2013). Though tolerance of larvae has not been specifically examined, larval survival is likely due to presence of colonies in saline regions (unlikely formed by drifting adults) (Sylvester et al. 2013). Though little to no ship traffic arrives to the Great Lakes from South American or Asian ports, the potential exists.

Limnoperna fortunei has a High probability of establishment if introduced to the Great Lakes (Confidence level: High).

Limnoperna fortunei can survive salinity shocks and changes allowing it transportation into the Great Lakes and the ability to acclimate to salinities around the Great Lakes. This species is already found in regions with climates similar to the Great Lakes and shows the ability to survive overwinter temperatures as low as 0°C. L. fortunei consumes a variety of phytoplankton and zooplankton making it able to adjust its diet based on prey availability in the Great Lakes if introduced.

The native and introduced ranges of L. fortunei include extremes of pollution, water temperature, pH, and nutrient levels, making it able to adapt to the many microhabitats throughout the Great Lakes. Limnoperna fortunei attaches well to hard substrate (including of biological origin), minimally to soft substrate, as well as macrophytes and reeds (Karatayev et al. 2007) and plastic bottles (Karatayev et al. 2010).

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

Environmental	Socioeconomic	Beneficial

Limnoperna fortunei reach large densities (5000-250,000 individuals/m2 on hard substrate, and 90-2000 individuals/m2 on soft substrate; Frau et al. 2013) shifting productivity in the nutrient cycle from the pelagic zone to the benthic zone. This species filters water quickly clarifying water causing a reduction in primary production occurring within the water column. Nutrient concentrations and proportion are shifted to promote aggregation of solitary Microcystis spp. cells; this favors blooms of the noxious cyanobacteria (Cataldo et al. 2012).

Limnoperna fortunei has the potential for high socio-economic impact if introduced to the Great Lakes.
L. fortunei modifies nutrient concentrations and proportions, and promotes aggregation of solitary Microcystis spp. cells into colonies; both these effects can favor blooms of this often noxious cyanobacteria (Cataldo et al. 2012). Gazulha et al. (2012) found that while single cells of cyanobacteria were accepted, filamentous and colonial cyanobacteria were rejected as pseudofeces, a preference that could enhance blooms.

Limnoperna fortunei can clogging/fouling water intake sieves and filters, pipes, heat exchangers, and condensers has become a common difficulty in industrial and power plants that use raw water, chiefly for cooling purposes (Cataldo et al. 2003, Goto 2002, Boltovskoy et al. 2009).

Limnoperna fortunei has the potential for high beneficial impact if introduced to the Great Lakes.

Glyphosate (commercial name: Roundup) is an herbicide with negative impacts on aquatic filtering organisms and sediment feeders. Experiments show that glyphosates (an herbicide) decrease by 40% under large mussel presence and by 25 % when empty shell are present. It is believed that that part of the herbicide which disappears from the water column is adsorbed in valvae surface, while another proportion is being mineralized by microbial communities in shells’ biofilm. Presence of Golden Mussel may speed up the bioavailability of the phosphorous in glyphosate, leading to eutrophication, but this is expected to be outweighed by the remediation of the herbicide (Di Fiori et al. 2012).

An increase in mussel densities have been associated with a threefold increase in Argentina's freshwater fish landings in the Rio do la Plata basin after 1995, due to its status as a new, abundant food source (Boltovskoy et al. 2006). The Rio de la Plata system is otherwise poor in plankton (Boltovskoy 2006).

According to Boltovskoy et al. (2006), positive impacts of L. fortunei are not limited to fishes that directly consume mussels, but there are also indirect positive effects on ichthyophagous and detritivorous fish species. Fish larvae, e.g. Salminus maxillosus, Rhaphiodon vulpinus, Pseudoplatystoma coruscans, Pseudoplatystoma fasciatum, and metalarvae of other Pimelodidae that prey on other larval fish probably benefit from the mussel-enhanced growth rates of their prey.

It is illegal to import, possess, deposit, release, transport, breed/grow, buy, sell, lease or trade L. fortunei in Ontario (Invasive Species Act 2015). Ohio lists L. fortunei as an injurious aquatic invasive species and therefore it is unlawful for any person to possess, import, or sell live individuals within the state. Dead golden mussels can only be possessed in Ohio if they are preserved in ethanol or formaldehyde, or eviscerated (internal organs removed) (OH ADM. Code, 1501:31-18-01).  In Michigan, it is illegal to possess, import, sell, or offer to sell L. fortunei (NREPA Part 413 as amended, MCL 324.41302). Illinois lists L. fortunei as an injurious species as defined by 50 CFR 16.11-15. Therefore, L. fortunei cannot be possessed, propagated, bought, sold, bartered or offered to be bought, sold, bartered, transported, traded, transferred or loaned to any other person or institution unless a permit is first obtained from the Department of Natural Resources. Illinois also prohibits the release of any injurious species, including L.fortunei (17 ILL. ADM. CODE, Chapter 1, Sec. 805). It is prohibited to transport, possess, or introduce L. fortunei in Wisconsin (Wisconsin Chapter NR 40). There are no regulations on L. fortunei in Minnesota, Indiana, Pennsylvania, or New York.

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

Control

Biological

Previous studies conducted in South America have shown that L. fortunei was prominent in the diet of several species of native fish (Oliveira et al. 2010; Isaac et al. 2012). The ability of native predators to adapt to exotic prey is not uncommon (Carlsson et al. 2009; Oliveira et al. 2010; Isaac et al. 2012). Given the physical similarities between dreissenid mussels and L. fortunei it is likely that predators of Dreissena spp. would also feed on L. fortunei if it were to become established in the Great Lakes. Dreissenid predators such as Freshwater drum (Aplodinotus grunniens), Common carp (Cyprinus carpio), Round goby (Neogobius melanostomus), Pumpkinseed (Lepomis gibbosus), Lake whitefish (Coregonus clupeaformis), Channel catfish (Ictalurus punctatus), and Diving duck (Aythya spp.), which are common in Great Lakes coastal wetlands (Herdendorf 1987, Bookhout et al. 1989, Johnson 1989 in Bowers and de Szalay 2007) could potentially reduce population densities of L. fortunei. However, predation by species maladapted to digest L. fortunei could also aid in its dispersal. Oliveira et al. (2010) found intact mollusks in several fish species suggesting that the mollusks could not be digested and therefore could be passed through alive.
The use of biocides to control L. fortunei has been examined. The commercial biocide Bulab 6002®, a quaternary ammonium polymer, rendered all L. fortunei larvae inactive after 24 hours at low concentrations (1 mg/L). This biocide may be effective in preventing larval settlement since inactive larvae do not secrete the byssus necessary to attach to substrate (Darrigran et al. 2007).  The use of the bacterium Pseudomonas flourescens CL145A, commercially known as Zequanox®, is highly lethal to dreissenid mussels and can affect L. fortunei (GLMRIS 2012; Rackl et al., 2012).

Physical

Physical control methods for Dreissena polymorpha could be implemented for L. fortunei control. These methods include thermal treatments, mechanical filtration, mechanical cleaning (scraping, brushing, and pigging), high-pressure jet cleaning, carbon dioxide pellet blasting, freezing, desiccation, acoustics, electric fields and UV light (Boelman et al. 1997). The tolerance of L. fortunei to desiccation is pertinent to the control of this species. One study found that golden mussels exposed to air without humidity control (49 to 63% relative humidity) did not survive more than 120 hours whereas mussels in more humid environments survived up to 168 hours. Therefore, desiccation is a viable option to reduce biofouling but water must be periodically removed for at least six days and this should be accompanied by procedures to reduce the relative humidity of the environment (Darrigran et al. 2004). High frequency turbulent flow (>30 Hz) is an effective way of killing L. fortunei veligers, but the energy required to create this turbulence may restrict its practical application (Xu et al. 2015).

Chemical

Chemical treatments such as chlorination or the use of commercial, non-oxidizing molluscicides can be effective against L. fortunei but water temperature and concentration can affect the efficiency of these chemical agents (Cataldo et al. 2008). The life stage of the mussels often dictates the control strategy. Targeting juveniles (5-8 mm in size) is often the most effective strategy because they are less tolerant than adults (thus requiring lower toxicant concentrations and exposure times), they detach more readily from surfaces, and they do not require continuous application throughout the reproductive period as do planktonic larvae.  It is beneficial to prevent juveniles from reaching the next stage because adults can form dense mats and significantly impact water flow. Therefore, in order to maximize the overall effectiveness of these treatments while minimizing environmental impact it is imperative to understand the timing of reproduction of L. fortunei (Boltovskoy et al. 2009).  Limnoperna begin reproducing in spring and cease reproducing in fall at temperatures around 16-17 °C, providing an extended period of reproduction in warm ecosystems. The mussels are dioecious and reproduce via external fertilization. Larvae undergo several pelagic development stages before settling and attaching to the substrate 11-20 days after spawning (Cataldo et al. 2005)

Other

Xu et al. (2015) studied the effectiveness of an ecological integrated approach to control L. fortunei biofouling in water transfer tunnels. The authors developed a prevention pool that aimed at reducing living veligers entering and attaching onto a water transfer tunnel. In the experiment water entered through a fore bay and into the pool that consisted of three attachment sections. The first two sections consisted of bamboo rafts that served as suitable material for mussel attachment and the third section contained geotextile frames used to absorb veligers that were not capable of stable attachment to the bamboo. In order to limit the mussel density in the bamboo sections these areas were filled with predators of L. fortunei: Carassius auratus (Common name: Goldfish) and Channa argus (Common name: Northern snakehead). Pipes in the end section of the prevention pool created high frequency turbulent flows as a final measure to guarantee the reduction of living veligers. The authors noted that the use of the predatory fish played an important role in restraining the attachment density and shell length of the golden mussel in the prevention pool. The experiment yielded an 80% reduction rate of living veligers in water that passed through the pool and a sharp decrease in mussel attachment density was observed as distance from the pool entrance increased. This method was tested at a pump station on the Xizhijiang River in China where the construction of an integrated ecological prevention pool yielded an 80% reduction in attachment density from 2012 to 2013. Using prevention pools on water intake structures in the Great Lakes could be an effective way to reduce biofouling, but the use of the Carassius auratus and Channa argus is not preferable since these species are not indigenous to the basin.

Note: Check state and local regulations for the most up-to-date information regarding permits for pesticide/herbicide/piscicide/insecticide use.