Susceptibility of quagga mussels (Dreissena rostriformis bugensis) to hot-water sprays as a means of watercraft decontamination

The recent spread of dreissenid mussels to various bodies of water in the western US has sparked interest by many state and federal agencies to develop protocols to stop further expansion. Quagga mussels (Dreissena rostriformis bugensis) are of particular importance as they are currently the most widespread dreissenid species in the region. This project examined the susceptibility of quagga mussels to hot-water sprays at different temperatures and durations of spray contact at Lake Mead (Nevada-Arizona, USA). Emersed adult quagga mussels were exposed to hot-water sprays at 20, 40, 50, 54, 60, 70, and 80°C for 1, 2, 5, 10, 20, 40, 80, and 160?s. Sprays at ≥60°C for 5?s were shown to be 100% lethal. Sprays of 54°C for 10?s, 50°C for 20?s, and 40°C for 40?s also resulted in 100% mortality. A spray temperature of 60°C for 5?s is recommended for mitigating fouling by quagga mussels.     

Assessing the effects of application time and temperature on the efficacy of hot-water sprays to mitigate fouling by Dreissena polymorpha (zebra mussels Pallas)

Dreissenid mussel (Dreissena polymorpha, Dreissena rostriformis bugensis) expansion into the Western US has renewed interest in hot-water spray mitigation of mussel fouling on boat hulls, trailers, and other equipment. However, the efficacy of hot-water sprays to mitigate dreissenid fouling has not been experimentally assessed. Emersed, adult D. polymorpha were exposed to low-pressure, hot-water sprays at 40, 50, 60, 70, and 80°C for 1, 5, or 10 s. Sprays at ≥60°C for 10 s or 80°C at ≥5 s were 100% lethal. In contrast, 1–10 s exposures did not induce 100% mortality at ≤50°C. The results indicate that mitigation of D. polymorpha fouling, especially in areas protected from the hydraulic impacts of high-pressure sprays requires spray temperatures of > 80°C applied for >5 s or no less than 60°C applied for >10 s. Thus, presently recommended spray temperatures of ≥60°C may not be 100% effective unless applied for >10 s.     

Potential effects on zooplankton from species shifts in planktivorous mussels: a field experiment in the St Lawrence River

1. Suspension feeding by bivalves exceeds that by other planktivores in many North American rivers, and food webs may be altered substantially by differences in feeding patterns between native unionid mussels and invading dreissenid mussels. 2. We conducted an experiment comparing zooplanktivory by one unionid and two dreissenid species that addressed several primary questions. Is benthic planktivory important in this river? Has this linkage been altered substantially by dreissenids? Do the two dreissenid species differ in planktivory, and is this ecologically important if quagga mussels extend their geographical range? 3. Our 12‐day experiment consisted of controls (no mussels) and treatments with unionid (Elliptio complanata), quagga (Dreissena bugensis) or zebra (D. polymorpha) mussels in 3500‐L, 80‐μm mesh enclosures placed in a slackwater area of the St Lawrence River. 4. The density of the most abundant calanoid copepod Eurytemora affinis increased in the presence of dreissenids, probably as an indirect food web response. By day 12, a cumulative effect was shown by the most overwhelmingly abundant rotifer, Polyarthra, whose density declined dramatically in dreissenid enclosures compared with control and unionid enclosures. Rotifer densities in unionid enclosures were not different from controls, nor were dreissenid treatments different from each other. The effects on rotifers were probably from predation, as Chl‐a did not vary among treatments. 5. We conclude that benthic‐pelagic coupling via planktivory is important in slackwater areas. Dreissenids have strengthened this linkage, but range extension of quaggas should not appreciably alter effects produced by a similar biomass of zebra mussels.     

Preferential manganese accumulation in dreissenid byssal threads

The elemental composition of byssal threads from two freshwater mussels Dreissena polymorpha (zebra) and Dreissena bugensis (quagga) has been determined by proton-induced X-ray emission spectroscopy. Sulphur and manganese are present at 30–100-fold higher concentrations in the threads than in ambient waters of Lake Erie. Calcium, phosphorus and copper levels are also somewhat enhanced in byssus. Since dreissenid byssus is not mineralized, Mn may be organometallically complexed to the functional side chains of byssal proteins.     

Testing a typology system of running waters for conservation planning in Hungary

The zebra mussel (Dreissena polymorpha) and its congener the quagga mussel (Dreissena rostriformis bugensis) are both invaders in freshwater, but have very different invasion histories, with zebra mussels attaining substantially faster rates of spread at virtually all spatial scales. However, in waterbodies where they co-occur, D. r. bugensis can displace D. polymorpha. To determine if the mechanisms for this displacement are associated with different survival and growth, we kept mussels in flow-through tanks for 289 days with two temperature regimes that mimicked the natural surface water (littoral zone) and hypolimnion conditions of Lake Erie. For the littoral zone regime, we used water directly from the surface of Lake Erie (range 4–25°C, average 11.9 ± 0.6°C). For the profundal zone treatment, Lake Erie surface water was chilled to about 6°C (range 5–8°C, average 6.2 ± 0.6°C) for the full duration of the experiment. For each of these temperature regimes, we used three replicate tanks with only zebra mussels present and three replicate tanks with only quagga mussels (150 ind./tank each), and three replicate tanks with both species (75 ind./tank of each species). Quagga mussels had higher survivorship and grew more than zebra mussels in all treatments. For both species, the size of the mussel entering the winter was critical for survivorship. Larger mussels had a higher survival over the winter in all treatments. For both species, there was a survivorship and growth tradeoff. In the warmer littoral zone treatment both species had higher growth, but lower survival than in the colder profundal zone treatment. Surprisingly, although quagga mussels outperformed zebra mussels, zebra mussel survivorship was better when they were faced with competition by quagga mussels than with just intraspecific competition. In addition, quagga mussels suffered size-specific mortality during the growing season only when facing interspecific competition with zebra mussels. Further experiments are needed to determine the possible mechanisms for these interspecific effects.     

Preface: Blasts from the past and back to the future

The invasion of dreissenid mussels into inland waters of the Northern Hemisphere has received considerable attention and, both zebra mussels and quagga mussels continue to spread westward. Despite studies aimed at understanding the biology of dreissenid mussels, relatively few studies have focused on water velocity and other hydrodynamic characteristics of water flow. The objective of this review was to identify, through a search of online databases, the papers that have been made available that directly have assessed the influence of hydrodynamic characteristics of water flow on dreissenid mussel biology. Using Thompson Reuters Web of Science, Google Scholar, and other resources, 46 papers were identified. These papers detailed that metrics associated with hydrodynamics of water flow, including current, wave action, velocity, flow rate, and discharge, can influence the biology of dreissenid mussels (primarily zebra mussel, which were studied far more than quagga mussel). Hydrodynamic characteristics influenced external fertilization, larval development and settlement, juvenile recruitment and attachment, and suspension feeding, growth and abundance of adults. In most cases, the impact of higher flow rates were locally negative and may present an opportunity for applications of water flow to control the spread or establishment of dreissenid mussels. Several knowledge gaps have been identified.

     

Microsatellite loci for dreissenid mussels (Mollusca: Bivalvia: Dreissenidae) and relatives: markers for assessing exotic and native populations

We developed and tested 14 new polymorphic microsatellite loci for dreissenid mussels, including the two species that have invaded many freshwater habitats in Eurasia and North America, where they cause serious industrial fouling damage and ecological alterations. These new loci will aid our understanding of their genetic patterns in invasive populations as well as throughout their native Ponto-Caspian distributions. Eight new loci for the zebra mussel Dreissena polymorpha polymorpha and six for the quagga mussel D. rostriformis bugensis were compared with new results from six previously published loci to generate a robust molecular toolkit for dreissenid mussels and their relatives. Taxa tested include D. p. polymorpha, D. r. bugensis, D. r. grimmi, D. presbensis, the 'living fossil'Congeria kusceri, and the dark false mussel Mytilopsis leucophaeata (the latter also is invasive). Overall, most of the 24 zebra mussel (N = 583) and 13 quagga mussel (N = 269) population samples conformed to Hardy-Weinberg equilibrium expectations for the new loci following sequential Bonferroni correction. The 11 loci (eight new, three previously published) evaluated for D. p. polymorpha averaged 35.1 alleles and 0.72 mean observed heterozygosity per locus, and 25.3 and 0.75 for the nine loci (six new, three previously published) developed for D. r. bugensis. All but three of these loci successfully amplified the other species of Dreissena, and all but one also amplified Congeria and Mytilopsis. All species and populations tested were significantly divergent using the microsatellite data, with neighbour-joining trees reflecting their evolutionary relationships; our results reveal broad utility for resolving their biogeographic, evolutionary, population and ecological patterns.     

Predator‐induced morphological defences in two invasive dreissenid mussels: implications for species replacement

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Population genetic history of the dreissenid mussel invasions: expansion patterns across North America

This study tests population genetic patterns across the Eurasian dreissenid mussel invasions of North America—encompassing the zebra mussel Dreissena polymorpha (1986 detection) and the quagga mussel D. rostriformis bugensis (detected in 1990, which now has largely displaced the former in the Great Lakes). We evaluate their source-spread relationships and invasion genetics using 9–11 nuclear microsatellite loci for 583 zebra mussels (21 sites) and 269 quagga mussels (12 sites) from Eurasian and North American range locations, with the latter including the Great Lakes, Mississippi River basin, Atlantic coastal waterways, Colorado River system, and California reservoirs. Additionally, mtDNA cytochrome b gene sequences are used to verify species identity. Our results indicate that North American zebra mussels originate from multiple non-native northern European populations, whereas North American quagga mussels trace to native estuaries in the Southern Bug and Dnieper Rivers. Invasive populations of both species show considerable genetic diversity and structure (zebra F _ST = 0.006–0.263, quagga F _ST = 0.008–0.267), without founder effects. Most newer zebra mussel populations have appreciable genetic diversity, whereas quagga mussel populations from the Colorado River and California show some founder effects. The population genetic composition of both species changed over time at given sites; with some adding alleles from adjacent populations, some losing them, and all retaining closest similarity to their original composition. Zebra mussels from Kansas and California appear genetically similar and assign to a possible origin from the St. Lawrence River, whereas quagga mussels from Nevada and California assign to a possible origin from Lake Ontario. These assignments suggest that overland colonization pathways via recreational boats do not necessarily reflect the most proximate connections. In conclusion, our microsatellite results comprise a valuable baseline for resolving present and future dreissenid mussel invasion pathways.     

Invasive mussels modify the cycling,storage and distribution of nutrients and carbon in a large lake

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Experiments on the time of application of insecticide to decrease the spread of yellowing viruses of sugar beet, 1954-66

Sprays of demeton-methyl insecticide decreased the spread of yellowing viruses by aphids in sugar-beet crops in England. Between 1957 and 1960, when yellows was prevalent, the incidence, assessed as ‘infected-plant-weeks’, was decreased by 36–41 % by one spray, depending on when it was applied, and by 55 % by two sprays, giving average yield increases of 1½ and 2 ton/acre of roots respectively. Between 1962 and 1966, when yellows spread less, a spray at the time when growers were advised to spray by the British Sugar Corporation decreased yellows incidence by 37 %, whereas sprays 2 weeks earlier or later decreased it by 24 % and 25 % respectively. Between 1958 and 1966 an annual average of 160000 of the country's 440000 acres of sugar beet has been sprayed, often to control Aphis fabae as well as to check the spread of yellows. A spray gives a profitable yield increase when yellows incidence in unsprayed plots is 20 % at the end of August.     

Habitat Shift in Invading Species: Zebra and Quagga Mussel Population Characteristics on Shallow Soft Substrates

Unexpected habitat innovations among invading species are illustrated by the expansion of dreissenid mussels across sedimentary environments in shallow water unlike the hard substrates where they are conventionally known. In this note, records of population characteristics of invading zebra (Dreissena polymorpha) and quagga (Dreissena bugensis) mussels from 1994 through 1998 are reported from shallow (less than 20m) sedimentary habitats in western Lake Erie. Haphazard SCUBA collections of these invading species indicated that combined densities of zebra and quagga mussels ranged from 0 to 32,500 individuals per square meter between 1994 and 1998, with D. polymorpha comprising 75–100% of the assemblages. These mixed mussel populations, which were attached by byssal threads to each other and underlying sand-grain sediments, had size–frequency distributions that were typical of colonizing populations on hard substrates. Moreover, the presence of two mussel cohorts within the 1994 samples indicated that these species began expanding onto soft substrates not later than 1992, within 4 years of their initial invasion in western Lake Erie. Such historical data provide baselines for interpreting adaptive innovations, ecological interactions and habitat shifts among the two invading dreissenid mussel species in North America.     

The influence of pre‐settlement and early post‐settlement processes on the adult distribution and relative dominance of two invasive mussel species

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Rapid range expansion of the invasive quagga mussel in relation to zebra mussel presence in The Netherlands and Western Europe

Since its appearance in 2006 in a freshwater section of the Rhine–Meuse estuary (Hollandsch Diep, The Netherlands), the non-indigenous quagga mussel has displayed a rapid range expansion in Western Europe. However, an overview characterising the spread and impacts of the quagga mussel in this area is currently lacking. A literature study, supplemented with field data, was performed to gather all available data and information relating to quagga mussel dispersal. Dispersal characteristics were analysed for rate and direction and in relation to hydrological connectivity and dispersal vectors. To determine ranges of conditions suitable for quagga mussel colonisation, physico-chemical characteristics of their habitats were analysed. After its initial arrival in the freshwater section of the Rhine-Meuse estuary and River Danube, the quagga mussel demonstrated a rapid and continued range expansion in Western Europe. Quagga mussels have extended their non-native range to the network of major waterways in The Netherlands and in an upstream direction in the River Rhine (Germany), its tributaries (rivers Main and Moselle) and the River Meuse (Belgium and France). The calculated average quagga mussel dispersal rate in Europe was 120 km year^?1 (range 23–383 km year^?1). Hydrological connectivity is important in determining the speed with which colonisation occurs. Dispersal to water bodies disconnected from the freshwater network requires the presence of a suitable vector e.g. pleasure boats transferred over land. Upstream dispersal is primarily human mediated through the attachment of mussels to watercraft. The relative abundance of quagga mussel to zebra mussel has greatly increased in a number of areas sampled in the major Dutch rivers and lakes and the rivers Main and Rhine and the Rhine–Danube Canal leading to a dominance shift from zebra mussels to quagga mussels. However, evidence for displacement of the zebra mussel is limited due to the lack of temporal trends relating to the overall density of zebra and quagga mussel.     

Invasive quagga mussels can be attenuated by redear sunfish (Lepomis microlophus) in the Southwestern United States

The degree to which invasive quagga mussels have spread across the Southwestern United States is unprecedented, and until now, none of the controls currently available is risk-free to the environment or human health. Here we demonstrate that stocking high-density (0.42 fish/m³ or 1.90 fish/m²) redear sunfish (Lepomis microlophus) in an infested lake enclosure removed adult quagga mussels efficiently and appeared to suppress their growth and recruitment. However, mussels were not eradicated during the short term experimental course. Long-term study needs to be conducted to determine whether mussels can be completely eliminated by redear sunfish and what optimum density would be required for balancing high efficacy mussel control with cost-effectiveness. Redear sunfish is a species native to the Southeastern United States that has become a popular, stocked sportfish in the Southwest. Targeted stocking of redear sunfish may be an efficient and environmentally friendly approach to mitigate the colonization of invasive quagga mussels in suitable open water ecosystems, especially those with new dreissenid infestations or those threatened by invasion.     

Coping with warmer, large rivers: a field experiment on potential range expansion of northern quagga mussels (Dreissena bugensis)

SUMMARY 1. Zebra mussels ( Dreissena polymorpha ) have established a much greater range in North America and Europe than quagga mussels ( D. bugensis ), which occupy a very similar niche.
2. We hypothesised that quaggas are physiologically capable of sustaining populations in warmer rivers currently occupied only by zebra mussels and that unidentified, non-physiological factors account for their more limited distribution.
3. Growth and survival of individually tagged mussels (976 D. bugensis from Lake Erie; 2625 D. polymorpha from Lake Erie and the Ohio River) were recorded monthly for up to 15 months in an outdoor stream mesocosm receiving unfiltered water from the Ohio River.
4. Extreme temperatures stressed both species; but in contrast to several previous laboratory studies, quaggas survived high temperatures better than zebra mussels. We suspect this was the result of species-specific differences in their ability to obtain, assimilate and/or catabolise food at high, sublethal temperatures.
5. A unimodal growth pattern was observed in both species, with the highest growth rates from late spring to early autumn.
6. Our survival and growth data suggest that quaggas are not physiologically limited from expanding southward.
7. While lacking definitive proof that dreissenid populations in rivers are ecologically sustainable without upstream lentic ecosystems and/or unintended human intervention, we suggest that complex river currents and upstream retentive and highly productive slackwater habitats in rivers may help sustain downstream populations of these meroplanktonic, dreissenid mussels.     

Optimising settlement assays of pediveligers and plantigrades of Mytilus galloprovincialis

The mussel Mytilus galloprovincialis is a common aquaculture species, and also a major fouling organism that has negative economic impacts. There are no standard assay conditions for this important species and therefore, this study quantified the effect of key factors on the settlement of pediveligers and plantigrades. Density dependent settlement did not occur for either pediveligers or plantigrades. Settlement increased in drop assays in a 12 h light:12 h dark cycle, while bottom shade had no effect of any magnitude. In addition, settlement was significantly enhanced by storing pediveligers for between 4 and 24 days at 4°C. Overall, these data provide the template to optimise and standardise static laboratory settlement assays for mussels in order to develop materials that either enhance settlement for the aquaculture industry, or deter settlement for antifouling applications. Furthermore, simple mechanisms such as storage at 4°C can enhance settlement beyond current methods used in aquaculture hatcheries.     

Lake morphometry determines Dreissena invasion dynamics

Predicting the ecosystem effects of invasive species and the best control strategies requires understanding population dynamics and population regulation. Invasive bivalves zebra and quagga mussels (Dreissena spp.) are considered the most aggressive invaders in freshwaters and have become major drivers of ecosystem processes in the Laurentian Great Lakes. Combining all lake-wide studies of Dreissena spp. conducted in the Great Lakes, we found that invasion dynamics are largely governed by lake morphometry. Where both species are present, quagga mussels generally become dominant in 8–13 years. Thereafter, zebra mussels remain common in shallow lakes and embayments and lake-wide Dreissena density may remain similar, while in deep lakes quagga led to a near-complete displacement of zebra mussels and an ensuing dramatic increase in overall dreissenid density. In deep lakes, overall Dreissena biomass peaked later and achieved?~?threefold higher levels than in shallow lakes. Comparison with 21 waterbodies in North America and Europe colonized by both dreissenids confirmed that patterns of invasion dynamics found in the Great Lakes are very consistent with other waterbodies, and thus can be generalized to other lakes. Our biophysical model predicted that the long-term reduction in primary producers by mussel grazing may be fourfold less in deep compared to shallow lakes due to thermal stratification and a smaller proportion of the epilimnion in contact with the bottom. While this impact remains greatest in shallow areas, we show that when lakes are vertically well-mixed, dreissenid grazing impact may be greatest offshore, revealing a potentially strong offshore carbon and phosphorus sink.

     

Combined effects of spray‐drying conditions and postdrying storage time and temperature on Salmonella choleraesuis and Salmonella typhimurium survival when inoculated in liquid porcine plasma

The objective of this study was to determine the effectiveness of the spray‐drying process on the inactivation of Salmonella choleraesuis and Salmonella typhimurium spiked in liquid porcine plasma and to test the additive effect of immediate postdrying storage. Commercial spray‐dried porcine plasma was sterilized by irradiation and then reconstituted (1:9) with sterile water. Aliquots of reconstituted plasma were inoculated with either S. choleraesuis or S. typhimurium, subjected to spray‐drying at an inlet temperature of 200°C and an outlet temperature of either 71 or 80°C, and each spray‐drying temperature combinations were subjected to either 0, 30 or 60 s of residence time (RT) as a simulation of residence time typical of commercial dryers. Spray‐dried samples were stored at either 4·0 ± 3·0°C or 23·0 ± 0·3°C for 15 days. Bacterial counts of each Salmonella spp., were completed for all samples. For both Salmonella spp., spray‐drying at both outlet temperatures reduced bacterial counts about 3 logs at RT 0 s, while there was about a 5·5 log reduction at RT 60 s. Storage of all dried samples at either 4·0 ± 3·0°C or 23·0 ± 0·3°C for 15 days eliminate all detectable bacterial counts of both Salmonella spp.

Significance and Impact of the Study

Safety of raw materials from animal origin like spray‐dried porcine plasma (SDPP) may be a concern for the swine industry. Spray‐drying process and postdrying storage are good inactivation steps to reduce the bacterial load of Salmonella choleraesuis and Salmonella typhimurium. For both Salmonella spp., spray‐drying at 71°C or 80°C outlet temperatures reduced bacterial counts about 3 log at residence time (RT) 0 s, while there was about a 5.5 log reduction at RT 60 s. Storage of all dried samples at either 4.0 ± 3.0°C or 23.0 ± 0.3°C for 15 days was effective for eliminating detectable bacterial counts of both Salmonella spp.     

Kinetic study of controlled release of flavor compounds from spray-dried encapsulated yeast powder using dynamic vapor sorption–gas chromatography

The release profile of d-limonene and ethyl hexanoate was investigated using a dynamic vapor sorption (DVS) system coupled with gas chromatography. The flavors were encapsulated by spray drying using Saccharomyces cerevisiae cells from which β-glucan had been partially extracted. Relative humidity (RH) was stepped from 20% to 50, 60, 70, and 80% at 30, 40, 50, and 60ºC. The maximum release flux for d-limonene and ethyl hexanoate was around 12 and 28 mg/s?m²?g-powder at 80% RH and 60ºC incubation. The Weibull distribution function was well fitted with the experimental data to analyze release kinetics. The release mechanism parameter was greater than 1.0, which indicates a controlled release with initial induction time. The activation energy for ethyl hexanoate (6 kJ/mol) was lower than d-limonene (41 kJ/mol) at 80% RH, which indicates higher affinition of ethyl hexanoate to migrate from the lipid bilayer membrane towards the water phase.