Transoceanic ships as vectors for nonindigenous freshwater bryozoans

Aim The transport of organisms in ships’ ballast tanks is a dominant vector for aquatic invasions worldwide. Until recently, efforts to manage this vector have overlooked the potential transport of invertebrate resting stages in the residual waters and sediments within emptied ballast tanks, i.e. NOBOB (‘No Ballast On Board’) tanks. The resting stages (statoblasts) of freshwater bryozoans are often buoyant and locally abundant and thus can be taken up easily during ballasting operations. They are also resistant to extreme environmental conditions and can generate new colonies after being dormant for decades; as such, they would likely remain viable propagules after lengthy transport in ship ballast tanks. This study quantified the occurrence of freshwater bryozoan statoblasts in ballast tank sediments of transoceanic ships. Location North American Great Lakes. Methods We quantified the frequency of occurrence, abundance and diversity of bryozoans (as statoblasts) in residual sediment samples taken from 51 NOBOB tanks of 33 transoceanic ships visiting the Great Lakes from 2000 to 2002. Results Our study identified 11 species, comprising nearly 12% of the total number of freshwater bryozoans known worldwide. These include two exotic species unrecorded in the Great Lakes (Fredericella sultana and Lophopus crystallinus), an exotic species already established in the region (Lophopodella carteri) and three cosmopolitan species (Plumatella casmiana, P. fungosa and P. repens). Our estimates suggest that a ship with NOBOB tanks may carry up to 10⁶ statoblasts. Main conclusions The discovery of species unrecorded in the Great Lakes and the potentially large numbers of statoblasts being transported in ship ballast tanks indicate a significant risk of new species introductions. Furthermore, the presence of cosmopolitan species and an exotic species already established in the Great Lakes suggests the strong possibility of cryptic invasions via the introduction of exotic genotypes.     

Recent mass invasion of the North American Great Lakes by Ponto-Caspian species

The North American Great Lakes have been invaded and dramatically altered by more than 145 alien species. Many invasions have occurred during the past few decades because of the release of Eurasian ballast water from transoceanic ships. Current regulations require ships to exchange foreign ballast with highly saline water before entering the Great Lakes; this procedure should prevent colonization by strictly freshwater species, but species with broad salinity tolerance might survive transport in exchanged water. A recent series of invasions by euryhaline organisms from the Black and Caspian Seas region signals a new phase in the transformation of the Great Lakes - one that supports the concept of an 'invasional meltdown'.     

In situ hatching of invertebrate diapausing eggs from ships' ballast sediment

Ships that enter the Great Lakes laden with cargo carry only residual ballast water and sediment in ballast tanks. These ships are designated ‘no ballast on board’ (NOBOB) and constitute > 90% of inbound traffic. We conducted in situ experiments using emergence traps to assess the viability and the introduction potential of invertebrate diapausing stages present in ships’ ballast sediment. All trials commenced while vessels operated on the lower lakes (Erie, Ontario) and were completed 6–11 days later at ports on the upper lakes (Michigan, Lake Superior). Eight trials were conducted on four ships using five different ballast sediments. Hatching was observed on every ship, although not from all sediments on all ships. Overall hatch rates were very low (0.5 individuals per 500 g sediment), typically involving activation of < 0.05% of total eggs present. Five species of rotifers and copepod nauplii were hatched from ballast sediments, although only one or two species typically hatched from any one sediment. Results of this study indicate that hatching of diapausing eggs contained in ballast sediment of NOBOB ships poses a relatively low risk of invasion to the Great Lakes. However, as reproduction may occur in tanks, and non‐indigenous species may be involved in numerous introduction events, the risk posed by this vector is small but potentially important. While dormancy is a characteristic enabling enhanced survival during transportation in ballast tanks, it becomes a hindrance for introduction.     

Salinity tolerance of Great Lakes invaders

1. The Laurentian Great Lakes are among the most invaded freshwater ecosystems in the world. Historically, the major vector for the introduction of non‐indigenous species (NIS) has been the release of contaminated ballast water via transoceanic ships. Despite regulations implemented in 1993, requiring vessels carrying fresh ballast water to exchange this water with saline ocean water, new reports of invasions have continued. 2. NIS often have a wide environmental tolerance allowing them to adapt to and invade a variety of habitats. It has been hypothesized that NIS with broad salinity tolerance may be able to survive ballast water exchange (BWE) and continue to pose an invasion risk to the Great Lakes. 3. We tested the short‐term salinity tolerance of eight recent invaders to the Great Lakes, specifically three cladocera (Bosmina coregoni, Bythotrephes longimanus, Cercopagis pengoi), two molluscs (Dreissena polymorpha, Dreissena rostriformis bugensis), and one species each of the families Gammaridae, Mysidae and Gobidae (Echinogammarus ischnus, Hemimysis anomala, Neogobius melanostomus) to determine if they could have survived salinities associated with BWE. 4. Overall, short‐term exposure to highly saline water dramatically reduced survival of all species. Two different methods of BWE tested, simultaneous and sequential, were equally effective in reducing survival. Species that survived the longest in highly saline water either possess behavioural characteristics that reduce exposure to adverse environments (valve closure; both Dreissena species) or are reported to have some degree of salinity tolerance in their native region (Echinogammarus). Given that exposure in our trials lasted a maximum of 48 h, and that species in ballast tanks would typically be exposed to saline water for c. 5 days, it appears that BWE is an effective method to reduce the survival of these NIS. These results provide impetus for tightening policy and monitoring of BWE, in particular for ships entering the Great Lakes from freshwater ports.     

Viability of invertebrate diapausing eggs exposed to saltwater: implications for Great Lakes’ ship ballast management

International shipping has been the dominant vector of nonindigenous species introductions to the Laurentian Great Lakes over the past century. Apparent ballast-mediated invasions have been recorded in recent years, despite the implementation of voluntary ballast water exchange regulations in 1989. Since unregulated no-ballast-on-board vessels currently dominate inbound traffic to the Great Lakes, it has been proposed that live or dormant organisms contained in residual ballast of these vessels may be partially responsible for recent invasions. Alternatively, euryhaline species may pose a significant invasion threat because they can potentially survive ballast exchange. In this study, we explored whether exposure to open-ocean water (32) reduced the viability of invertebrate diapausing eggs in ballast sediments. Sediments collected from three transoceanic ships and from three freshwater habitats were exposed to open-ocean seawater. Egg viability, assessed as the abundance of taxa hatched between exposed and unexposed sediments, was not affected by saltwater exposure in any experiment. Species richness of hatched diapausing eggs was reduced by saltwater exposure in only one of seven trials. Our results indicate that oligostenohaline zooplankton may pose an invasion risk because their diapausing eggs are largely resistant to exposure to open-ocean saltwater.     

Efficacy of ‘saltwater flushing’ in protecting the Great Lakes from biological invasions by invertebrate eggs in ships’ ballast sediment

1. Mid‐ocean exchange and saltwater flushing were implemented as management practices to reduce the likelihood of new biological invasions in the Laurentian Great Lakes associated with ships’ ballast water and sediments. Despite this, there has been no formal assessment of the efficacy of these procedures. Here, we conduct a comparative analysis of community composition of dormant taxa transported by ballast sediment before and after regulations came into effect in 2006. 2. Ballast sediment samples were collected from 17 ships during the post‐regulation interval of 2007 and 2008. Invertebrate eggs were counted, hatched and species identified in the laboratory. Results were compared to similar samples collected from 39 ships between 2000 and 2002, prior to implementation of saltwater flushing regulations. 3. The estimated amount of residual ballast sediment transported by vessels was significantly lower during the post‐regulation period, ranging from <1 to 45 tonnes per ship, with an average of 5 tonnes. Mean density and number of dormant viable eggs per ship declined 91 and 81%, respectively. 4. Community composition also changed through time, with Rotifera accounting for 78% of taxa transported prior to regulation, whereas Cladocera and Copepoda each accounted for 38% of abundance post‐regulation. Although the number of non‐indigenous species (NIS) declined 73% per ship after 2006, the reduction was not statistically significant; however, the number of freshwater NIS – which pose the greatest risk of invasion for the Great Lakes – was significantly lowered. 5. Our comparative analysis suggests that ballast management regulations enacted in 2006 markedly reduced the probability of introduction of NIS via dormant eggs carried in ballast sediments.     

Domestic ships as a potential pathway of nonindigenous species from the Saint Lawrence River to the Great Lakes

Ballast water moved by transoceanic vessels has been recognized globally as a predominant vector for the introduction of aquatic nonindigenous species (NIS). In contrast, domestic ships operating within confined geographic areas have been viewed as low risk for invasions, and are exempt from regulation in consequence. We examined if the St. Lawrence River could serve as a source of NIS for the Laurentian Great Lakes by surveying ballast water carried by domestic vessels and comparing biological composition in predominant St. Lawrence River—Great Lakes port-pairs in order to determine the likelihood that NIS could be transported to, and survive in, the Great Lakes. Thirteen potential invaders were sampled from ballast water, while 26 taxa sampled from St. Lawrence River ports are not reported from the Great Lakes. The majority of NIS recorded in samples are marine species with low potential for survival in the Great Lakes, however two euryhaline species (copepod Oithona similis, and amphipod Gammarus palustris) and two taxa reported from brackish waters (copepod Microsetella norvegica and decapod Cancer irroratus) may pose a risk for invasion. In addition, four marine NIS were collected in freshwater samples indicating that at least a subset of marine species have potential as new invaders to the Great Lakes. Based on results from this study, the ports of Montreal, Sorel, Tracy and Trois Rivières appear to pose the highest risk for new ballast-mediated NIS from the St. Lawrence River to the Great Lakes.     

Transport of the harmful bloom alga Aureococcus anophagefferens by oceangoing ships and coastal boats

It is well established that cyst-forming phytoplankton species are transported in ships' ballast tanks. However, there is increasing evidence that other phytoplankton species which do not encyst are also capable of surviving ballast transit. These species have alternative modes of nutrition (hetero- or mixotrophy) and/or are able to survive long-term darkness. In our studies of no-ballast-on-board vessels arriving in the Great Lakes, we tested for the presence of the harmful algal bloom species Aureococcus anophagefferens (brown tide) in residual (i.e., unpumpable) ballast water using methods based on the PCR. During 2001, the brown tide organism was detected in 7 of 18 ballast water tanks in commercial ships following transit from foreign ports. Furthermore, it was detected after 10 days of ballast tank confinement during a vessel transit in the Great Lakes, a significant result given the large disparity between the salinity tolerance for active growth of Aureococcus (>22 ppt) and the low salinity of the residual ballast water (approximately 2 ppt). We also investigated the potential for smaller, recreational vessels to transport and distribute Aureococcus. During the summer of 2002, 11 trailered boats from the inland bays of Delaware and coastal bays of Maryland were sampled. Brown tide was detected in the bilge water in the bottoms of eight boats, as well as in one live-well sample. Commercial ships and small recreational boats are therefore implicated as potential vectors for long-distance transport and local-scale dispersal of Aureococcus.     

Transport of the Harmful Bloom Alga Aureococcus anophagefferens by Oceangoing Ships and Coastal Boats

It is well established that cyst-forming phytoplankton species are transported in ships' ballast tanks. However, there is increasing evidence that other phytoplankton species which do not encyst are also capable of surviving ballast transit. These species have alternative modes of nutrition (hetero- or mixotrophy) and/or are able to survive long-term darkness. In our studies of no-ballast-on-board vessels arriving in the Great Lakes, we tested for the presence of the harmful algal bloom species Aureococcus anophagefferens (brown tide) in residual (i.e., unpumpable) ballast water using methods based on the PCR. During 2001, the brown tide organism was detected in 7 of 18 ballast water tanks in commercial ships following transit from foreign ports. Furthermore, it was detected after 10 days of ballast tank confinement during a vessel transit in the Great Lakes, a significant result given the large disparity between the salinity tolerance for active growth of Aureococcus (>22 ppt) and the low salinity of the residual ballast water (~2 ppt). We also investigated the potential for smaller, recreational vessels to transport and distribute Aureococcus. During the summer of 2002, 11 trailered boats from the inland bays of Delaware and coastal bays of Maryland were sampled. Brown tide was detected in the bilge water in the bottoms of eight boats, as well as in one live-well sample. Commercial ships and small recreational boats are therefore implicated as potential vectors for long-distance transport and local-scale dispersal of Aureococcus.     

Is vessel hull fouling an invasion threat to the Great Lakes?

Aim  Hull fouling is a leading vector for the introduction of marine, non‐indigenous species (NIS) worldwide, yet its importance to freshwater habitats is poorly understood. We aimed to establish the complement of NIS transported via this vector to the Great Lakes and to determine if they pose an invasion risk. Location  Laurentian Great Lakes. Methods  During 2007 and 2008, we collected scrapings from exterior surfaces as well as underwater video‐transects from 20 vessels shortly after their arrival in Great Lakes’ ports. Invertebrates present were sorted and identified in the laboratory. Results  Total estimated abundance averaged > 170,000 invertebrates per ship belonging to 109 taxa. Most (72%) of these taxa were freshwater species already present in the Great Lakes, whereas 11 and 31% were native to estuarine and marine habitats respectively, and would not be expected to survive in this habitat. Abundance was dominated by barnacles (51%), cladocerans (19%), bivalves (12%) and amphipods (11%). Sea‐chest grating and the rudder were hot‐spots for biofouling. Invertebrate diversity and total abundance were positively associated with total time spent in port during the last year and time in Pacific South American ports and negatively related to time in high latitudes and sailing speed. Although we found some live, established invaders such as Gammarus tigrinus and Dreissena rostriformis bugensis, only one individual of a freshwater NIS (Alexandrovia onegensis, Oligochaeta) not yet reported in the Great Lakes was detected. The animal’s poor condition and seemingly low population abundance indicated the risk of live introduction by this vector was likely quite low. Main conclusion  Our results indicate that hull fouling appears to pose a low risk of introductions of new species capable of surviving in the Great Lakes, unlike foreign‐sourced freshwater ballast water that historically was discharged by these transoceanic vessels.     

Dynamics and short-term survival of toxic cyanobacteria species in ballast water from NOBOB vessels transiting the Great Lakes—implications for HAB invasions

We measured the presence, viability and potential toxicity of cyanobacteria in ships’ ballast tanks during three domestic voyages through the North American Great Lakes. Using molecular methods, the toxin-producing forms of Microcystis and Anabaena were monitored in ballast water after ships’ ballast tanks were filled at their first port of call, and at subsequent ports as ships transited the Great Lakes. Microcystis was detected in ballast water at intermediate and final ports of call in all three experiments, but the presence of Anabaena was more variable, suggesting low abundance or patchy distribution in ballast tanks. Both species were detected in ballast water up to 11 days old. Detection of the microcystin synthetase gene, mcyE, in ballast tanks indicated entrained cells were capable of producing microcystin, and further analyses of RNA indicated the toxin was being expressed by Microcystis, even after 11 days in dark transit. These data demonstrate within-basin transport and delivery of planktonic harmful algal bloom (HAB) species to distant ports in the world's largest freshwater reservoir, with potential implications for drinking water quality. These implications are discussed with respect to management of microbial invasions and the fate of introduced phytoplankton in their receiving environment.     

Expansion of tubenose gobies <Emphasis Type="Italic">Proterorhinus semilunaris</Emphasis> into western Lake Erie and potential effects on native species

The Eurasian freshwater tubenose goby Proterorhinus semilunaris (formerly Proterorhinus marmoratus) invaded the Laurentian Great Lakes in the 1990s, presumably via ballast water from transoceanic cargo ships. Tubenose gobies spread throughout Lake St. Clair, its tributaries, and the Detroit River system, and also are present in the Duluth-Superior harbor of Lake Superior. Using seines and bottom trawls, we collected 113 tubenose gobies between July 2007 and August 2009 at several locations in western Lake Erie. The number and range of sizes of specimens collected suggest that that tubenose gobies have become established and self-sustaining in the western basin of Lake Erie. Tubenose gobies reached maximum densities in sheltered areas with abundant macrophyte growth, which also is their common habitat in native northern Black Sea populations. The diet of tubenose gobies was almost exclusively invertebrates, suggesting dietary overlap with other benthic fishes, such as darters (Etheostoma spp. and Percina sp.), madtoms (Noturus spp.), and sculpins (Cottus spp.). A single mitochondrial DNA haplotype was identified, which is the most common haplotype found in the original colonization area in the Lake St. Clair region, suggesting a founder effect. Tubenose gobies, like round gobies Neogobius melanostomus, have early life stages that drift owing to vertical migration, which probably allowed them to spread from areas of colonization. The Lake St. Clair-Lake Erie corridor appears to have served as an avenue for them to spread to the western basin of Lake Erie, and abundance of shallow macrophyte-rich habitats may be a key factor facilitating their further expansion within Lake Erie and the remainder of the Laurentian Great Lakes.     

A Spatial Modeling Approach to Predicting the Secondary Spread of Invasive Species Due to Ballast Water Discharge

Ballast water in ships is an important contributor to the secondary spread of invasive species in the Laurentian Great Lakes. Here, we use a model previously created to determine the role ballast water management has played in the secondary spread of viral hemorrhagic septicemia virus (VHSV) to identify the future spread of one current and two potential invasive species in the Great Lakes, the Eurasian Ruffe (Gymnocephalus cernuus), killer shrimp (Dikerogammarus villosus), and golden mussel (Limnoperna fortunei), respectively. Model predictions for Eurasian Ruffe have been used to direct surveillance efforts within the Great Lakes and DNA evidence of ruffe presence was recently reported from one of three high risk port localities identified by our model. Predictions made for killer shrimp and golden mussel suggest that these two species have the potential to become rapidly widespread if introduced to the Great Lakes, reinforcing the need for proactive ballast water management. The model used here is flexible enough to be applied to any species capable of being spread by ballast water in marine or freshwater ecosystems.     

Salinity tolerance of diapausing eggs of freshwater zooplankton

1. Many freshwater zooplankton produce diapausing eggs capable of withstanding periods of adverse environmental conditions, such as anoxia, drought and extreme temperature. These eggs may also allow oligostenohaline species to survive increased salinity during periods of tidal flux or evaporation, and here we test the ability of diapause eggs to withstand such conditions. 2. Salinity tolerance may also enable organisms to invade new environments. The increased rate of introduction of non‐indigenous species to the Laurentian Great Lakes since 1989, when ballast water exchange regulations (to replace fresh/brackish water at sea with full seawater) were first implemented for transoceanic vessels, has stimulated studies that explore mechanisms of introduction, other than of active animals, in ballast water. One hypothesis proposes that freshwater organisms transported in ballast tanks as diapausing eggs may be partially responsible for the increased rate of species introduction, as these eggs may tolerate a wide array of adverse environmental conditions, including exposure to saline water. 3. We collected ballast sediments from transoceanic vessels entering the Great Lakes, isolated diapausing eggs of three species (Bosmina liederi, Daphnia longiremis and Brachionus calyciflorus), and measured the effect of salinity on hatching rate. In general, exposure to salinity significantly reduced the hatching rate of diapausing eggs. However, as non‐indigenous species can establish from a small founding population, it is unclear whether salinity exposure will be effective as a management tool.     

Linking environmental conditions and ship movements to estimate invasive species transport across the global shipping network

Aim Some nations, and the International Maritime Organization, are moving towards requirements for managing ballast water to reduce the number of alien species transported and released. These and other measures will be most efficient when targeted at ships posing the greatest risks. Here, we analyse world‐wide ship movements and port environmental conditions to explore how these risk components differ across arriving ships. Location Global, with a case study of the Laurentian Great Lakes. Methods We gathered salinity and temperature data for all global shipping ports, and data for all global ship movements during a 12 ‐month period. We applied these data to the Laurentian Great Lakes to determine which global ports may donate new species to the Great Lakes via ship traffic, and which are most environmentally similar to the Great Lakes. Results We show that ships regularly travel to the Great Lakes from all major coastal, and many inland, regions of the world. Most global ports, and thus the species in them, are separated from the Great Lakes by no more than two ship voyages. Combined with a measure of environmental similarity among global ports, we identify ship routes likely to transport species adapted for survival in the Great Lakes and global regions that may be the source of increasing future invasions. Main conclusions The Great Lakes account for a small fraction of global shipping yet are closely connected to all other ports, and the species in them, by the shipping network. Our methods and data allow risks from individual ships to be ranked so that management activities can be targeted at ships most likely to introduce new invaders. Because our data sets are global, they could be applied to ship arrivals at any global port.     

Does saltwater flushing reduce viability of diapausing eggs in ship ballast sediment?

Flushing of ballast tanks with seawater has been proposed to reduce the risk of invasion associated with residual ballast in 'no ballast on board' ships. The efficacy of this procedure, however, has not been determined. Using diapausing eggs isolated from ballast sediments — as well as from Lake Erie sediment — this study investigated the impact of salinity (0, 8 and 35‰) and temperature (10, 20 and 30 °C) on the cumulative abundance and species richness of hatched zooplankton taxa. The rate and amount of hatching varied dramatically between sediments and across salinity–temperature regimes. Although exposure to saline water inhibited emergence of freshwater taxa during the exposure phase of all trials, mixed results were evident after diapausing eggs were returned to freshwater. The efficacy of salinity as a ballast treatment method was temperature dependent, although the direction of the effect was case-specific. Exposure of eggs to saline water was less effective at 10 and 30 °C than at 20 °C. Although flushing ballast tanks with open ocean water is expected to significantly reduce the number of active invertebrates living in residual ballast water (a potentially larger source of invaders), our results indicate that the most effective treatment conditions for reduction of diapausing egg viability is 8‰ salinity at 20 °C.     

Acclimation and introduction of hydrobionts ships’ ballast water organisms in the Port of Vladivostok

Work on the investigation of organisms of ballast water and sediments of ships sailing on Russia-Japan and Russia-China lines was started in the Port of Vladivostok for the first time for the Far East seas of Russia. In total, 145 taxa, 37 microalgal species, 24 holoplankton species, 22 meroplankton taxa, and 10 meiofauna groups were revealed, 24 species of microscopic mycelia fungi were attributed, and 28 morphologically distinct bacterial stains were isolated. Potentially toxic microalgal species were found: the dinoflagellates Dinophysis acuminate and Prorocentrum cordatum and the diatom Pseudo-nitzschia pungens. The tropical-subtropical copepod Pseudocalanus inopinus was recorded in ballast water. Polychaete larvae of the Polydora genus with an unusual morphology, which were not occurring in the Peter the Great Bay previously, were recorded as probable southern migrants from the coastal waters of the southwest coast of Honshu Island. Live larvae of the hermit crab Diogenes nitidimanus were revealed in ballast water, supporting the possibility of introduction of this species in the Peter the Great Bay. Based on an analysis of the total number of colony-forming units of heterotroph microorganisms (within the order of 10³–10⁴ cells/ml), the ballast water of ships sailing on the Russia-Japan line was characterized as moderately polluted. The detection of Escherichia coli strains, exceeding the standards quoted in the International Convention by three times or more, showed the potential danger of a mass bioinvasion. Conditionally pathogenic and toxinogenic mycelial fungi, which are able to induce mycoses and mycotoxicoses in invertebrates and fishes, were isolated from ballast water. It was determined that ballast water of the “rusty” type was poorly suited for the existence of zoo- and phytoplankton forms. In the case of the construction of an oil terminal in the Peter the Great Bay, a sharp increase of the introduction of exotic species via the ballast water and foulings of tankers is inevitable     

Post-exchange zooplankton in ballast water of ships entering the San Francisco Estuary

The San Francisco Estuary in California (CA), USA, has beenheavily altered by invasions of nonnative zooplankton and benthicorganisms, presumably by the discharge of ships’ ballastwater. Since 2000, ships entering CA have been required to exchangeballast water with oceanic water during the voyage to decreasethe number of organisms discharged into the Estuary that hadpreviously been taken aboard at foreign ports. We examined abundanceof zooplankton in ballast water of 18 container ships and 48bulk carriers. Asia dominated the sources of ballast water,which contained multiple nonnative zooplankton including speciesthat have invaded and since become common residents in the Estuary.The abundance of zooplankton was significantly lower in ballastwater that had been emptied and refilled with oceanic waterthan those that had continuously been flushed with oceanic water(about three times the volume of ballast water), suggestingthat empty–refill is more effective in removing exoticzooplankton.     

Molecular detection of invasive species in heterogeneous mixtures using a microfluidic carbon nanotube platform

Screening methods to prevent introductions of invasive species are critical for the protection of environmental and economic benefits provided by native species and uninvaded ecosystems. Coastal ecosystems worldwide remain vulnerable to damage from aquatic species introductions, particularly via ballast water discharge from ships. Because current ballast management practices are not completely effective, rapid and sensitive screening methods are needed for on-site testing of ships in transit. Here, we describe a detection technology based on a microfluidic chip containing DNA oligonucleotide functionalized carbon nanotubes. We demonstrate the efficacy of the chip using three ballast-transported species either established (Dreissena bugensis) or of potential threat (Eriocheir sinensis and Limnoperna fortuneii) to the Laurentian Great Lakes. With further refinement for on-board application, the technology could lead to real-time ballast water screening to improve ship-specific management and control decisions.