Biometric conversion factors as a unifying platform for comparative assessment of invasive freshwater bivalves

Invasive bivalves continue to spread and negatively impact freshwater ecosystems worldwide. As different metrics for body size and biomass are frequently used within the literature to standardise bivalve-related ecological impacts (e.g. respiration and filtration rates), the lack of broadly applicable conversion equations currently hinders reliable comparison across bivalve populations. To facilitate improved comparative assessment among studies originating from disparate geographical locations, we report body size and biomass conversion equations for six invasive freshwater bivalves (or species complex members) worldwide: Corbicula fluminea, C. largillierti, Dreissena bugensis, D. polymorpha, Limnoperna fortunei and Sinanodonta woodiana, and tested the reliability (i.e. precision and accuracy) of these equations. Body size (length, width and height) and biomass metrics of living-weight (LW), wet-weight (WW), dry-weight (DW), dry shell-weight (SW), shell free dry-weight (SFDW) and ash-free dry-weight (AFDW) were collected from a total of 44 bivalve populations located in Asia, the Americas and Europe. Relationships between body size and individual biomass metrics, as well as proportional weight-to-weight conversion factors, were determined. For most species, although inherent variation existed between sampled populations, body size directional measurements were found to be good predictors of all biomass metrics (e.g. length to LW, WW, SW or DW: R2 = 0.82–0.96), with moderate to high accuracy for mean absolute error (MAE): ±9.14%–24.19%. Similarly, narrow 95% confidence limits and low MAE were observed for most proportional biomass relationships, indicating high reliability for the calculated conversion factors (e.g. LW to AFDW; CI range: 0.7–2.0, MAE: ±0.7%–2.0%). Synthesis and applications. Our derived biomass prediction equations can be used to rapidly estimate the biologically active biomass of the assessed species, based on simpler biomass or body size measurements for a wide range of situations globally. This allows for the calculation of approximate average indicators that, when combined with density data, can be used to estimate biomass per geographical unit-area and contribute to quantification of population-level effects. These general equations will support meta-analyses, and allow for comparative assessment of historic and contemporary data. Overall, these equations will enable conservation managers to better understand and predict ecological impacts of these bivalves.Fil: Coughlan, Neil E.. The Queens University of Belfast; Irlanda. University College Cork; IrlandaFil: Cunningham, Eoghan M.. The Queens University of Belfast; IrlandaFil: Cuthbert, Ross N.. The Queens University of Belfast; Irlanda. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: Joyce, Patrick W. S.. The Queens University of Belfast; IrlandaFil: Anastácio, Pedro. Universidade de Évora; PortugalFil: Banha, Filipe. Universidade de Évora; PortugalFil: Bonel, Nicolás. Université Montpellier II; Francia. Centre National de la Recherche Scientifique; Francia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida. Universidad Nacional del Sur. Centro de Recursos Naturales Renovables de la Zona Semiárida; ArgentinaFil: Bradbeer, Stephanie J.. University of Leeds; Reino UnidoFil: Briski, Elizabeta. Geomar-Helmholtz Centre for Ocean Research Kiel; AlemaniaFil: Butitta, Vince L.. University of Wisconsin; Estados UnidosFil: Cadková, Zuzana. Czech University of Life Sciences; República ChecaFil: Dick, Jaimie T. A.. The Queens University of Belfast; IrlandaFil: Douda, Karel. Czech University of Life Sciences; República ChecaFil: Eagling, Lawrence E.. The Queens University of Belfast; IrlandaFil: Ferreira Rodríguez, Noé. Universidad de Vigo; EspañaFil: Hünicken, Leandro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Johansson, Mattias L.. University of North Georgia; Estados UnidosFil: Kregting, Louise. The Queens University of Belfast; IrlandaFil: Labecka, Anna Maria. Jagiellonian University; PoloniaFil: Li, Deliang. Hunan Agricultural University; ChinaFil: Liquin, Florencia Fernanda. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Marescaux, Jonathan. University of Namur; Bélgica. e-biom; BélgicaFil: Morris, Todd J.. Fisheries and Ocean Canada; CanadáFil: Nowakowska, Patrycja. University of Gdansk; PoloniaFil: Ozgo, Malgorzata. Kazimierz Wielki University; PoloniaFil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Peribáñez, Miguel A.. Universidad de Zaragoza; EspañaFil: Riccardi, Nicoletta. Consiglio Nazionale delle Ricerche; ItaliaFil: Smith, Emily R. C.. University College London; Estados UnidosFil: Sylvester, Francisco. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentin

Susceptibility of invasive Asian clams to Chaetogaster limnaei: effect of parasite density and host size on infection dynamics

The release from enemies in the introduced range has often been proposed as an explanations for the success of invasive species in the ecosystems they colonize. The genus Corbicula comprises several conspicuous and comparatively well-studied invasive clam species in freshwater habitats worldwide, yet parasitological studies on this group are scarce. We conducted a thorough parasitological assessment of the two Corbicula spp. present in Argentina, using populations from two early colonization sites in Río de la Plata and two sites of recent colonization in Salta. Corbicula fluminea and C. largillierti clams from Río de la Plata were found to be naturally infected with C. limnaei oligochaete worm gill parasites, while C. largillierti clams from Salta were free of any parasites. To evaluate the susceptibility of Salta populations to infection, we exposed clams of two sizes to three different oligochaete concentrations in the laboratory. At all concentrations tested, we obtained infected clams, and both prevalence and mean intensity of infection increased with oligochaete concentration. The field and laboratory studies showed that small clams from both species reached significantly higher worm prevalence than large conspecifics, although in the field this effect was population dependent. The present results indicate that C. largillierti does not lack natural enemies nor has acquired immunity to them in the locations examined. Instead, the worm's absence from wild clam populations is likely related with a low availability of parasites in the aquatic habitats occupied by C. largillierti in northwestern Argentina. The different ways in which freshwater invasive bivalves may obtain release from parasites may play a role in their collective success as an invasive group.Fil: Liquin, Florencia Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; ArgentinaFil: Sylvester, Francisco. Goethe Universitat Frankfurt; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; ArgentinaFil: Davies, Dora Ana. Universidad Nacional de Salta; Argentin

A new species of Auriculostoma (Digenea:Allocreadiidae) in South America: life cycle and phylogenetic relationships

Auriculostoma is a Neotropical distributed genus of flatwormsflatworm's digeneans whose adults are parasites of freshwater fishes. We describe the new species Auriculostoma ocloya using morphological and molecular tools, and elucidate its life cycle, the first known of a species of this genus. The first intermediate host is the bivalve Pisidium ocloya, the second intermediate host is the amphipod Hyalella sp., and the definite hosts are siluriform fishes. The adult presents a single pair of muscular lobes on either side of the oral sucker with a broad base, stretching from ventrolateral to dorsolateral, structure also present in the rest of species of the genus. Nevertheless, the new species is set apart from all congeners because the posterior ?free? ends of the lobes are not present in our specimens. This is the first study to provide sequence data from larval and adult stages of Auriculostoma species in South America. Our analyses demonstrated the basal position and strong separation of the new specie from other members of the genus likely reflects the ancient nature of their host association. Our study even with limited data allowed us to reveal important trends in the evolution of their morphological traits, host associations and geographic distribution.Fil: Liquin, Florencia Fernanda. Universidad Nacional de Salta; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gilardoni, Carmen Mariangel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Departamento de Zoología. Laboratorio de Parasitología; ArgentinaFil: Cremonte, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto de Biología de Organismos Marinos; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Departamento de Zoología. Laboratorio de Parasitología; ArgentinaFil: Saravia, José. Universidad Nacional de Salta; ArgentinaFil: Cristobal, Hector Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentina. Universidad Nacional de Salta. Facultad de Ciencias Naturales; ArgentinaFil: Davies, Dora Ana. Universidad Nacional de Salta. Facultad de Ciencias Naturales; Argentin

Parasitism and fitness of invaders: oligochaete Chaetogaster limnaei produces gill damage and increased respiration rates in freshwater Asian clams

Biological interactions between invasive and resident species are perceived as a key factor mediating impacts in invaded ecosystems, although symbiotic interactions have received relatively little attention. To evaluate the association between the invasive clam Corbicula fluminea and its oligochaete symbiont Chaetogaster limnaei, we conducted laboratory assessments of prevalence and intensity of infection, external and internal macroscopic alterations, and histological analyses of the gills of uninfected and infected clams collected from the shores of the Río de la Plata estuary in Argentina. To evaluate potential ramifications of physical alterations on physiological traits and host fitness, we conducted respiration experiments on the same clams. Worm prevalence was higher in smaller than large clams. While no macroscopical alterations were detected, several histopathological changes were observed in the gills of infected clams. Infected clams had significantly higher metabolic rates than uninfected conspecifics and smaller clams had higher metabolic rates than larger conspecifics. Increased host metabolic rates, even at very low infections intensities, were likely a compensatory response to the stress caused by gill damaged inflicted by the oligochaetes. The relationship between C. limnaei and invasive C. fluminea in Río de la Plata best fits as parasitism.Fil: Liquin, Florencia Fernanda. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Hünicken, Leandro Andrés. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Arrighetti, Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Davies, Dora Ana. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; ArgentinaFil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Sylvester, Francisco. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; Argentin

The life cycle of Magnivitellinum saltaensis n. sp. (Digenea: Alloglossidiidae) in Salta Province, Argentina

We describe the alloglossiid trematode Magnivitellinum saltaensis n. sp., a parasite of the characiform fish Psalidodon endy, and its life cycle from Salta, northwest of Argentina. This is the first life cycle described for a species belonging to the genus Magnivitellinum. Cercariae emerged naturally from Biomphalaria tenagophila snails and infected experimentally exposed larvae of Diptera and Ephemeroptera as second intermediate hosts. These larvae in turn were exposed to commercially raised fish, and adults were recovered from characiform albino fish Gymnocorymbus ternetzi. Molecular analysis of natural and experimental adults showed the same genetic sequence for the partial region of 28S rDNA, thus confirming conspecificity. Comparison of these sequences with those published for M. simplex from Mexico showed 1.45% divergence, indicating that the specimens found in Salta belong to a different species, the third described of Magnivitellinum, in agreement with morphological data, geographical location, and host species composition. The new species is distinguished by its small body, vitelline follicles extending from the mid-level of the ventral sucker, Y-shaped excretory vesicle, and presence of papillae around the mouth.Fil: Davies, Dora Ana. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Liquin, Florencia Fernanda. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Lauthier, Juan José. Kochi University. Kochi Medical School; JapónFil: Párraga, Regina. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; ArgentinaFil: Saravia, José. Universidad Nacional de Salta. Facultad de Ciencias Naturales. Instituto para el Estudio de la Biodiversidad de Invertebrados; ArgentinaFil: Davies, Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Ostrowski de Núñez, Margarita. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentin

Better integration of chemical pollution research will further our understanding of biodiversity loss

Chemical pollution research should be better integrated with other drivers of biodiversity loss and the assessment of human impacts on ecosystems, to more effectively guide management strategies for biodiversity loss mitigation

Biometric conversion factors as a unifying platform for comparative assessment of invasive freshwater bivalves

Invasive bivalves continue to spread and negatively impact freshwater ecosystems worldwide. As different metrics for body size and biomass are frequently used within the literature to standardise bivalve related ecological impacts (e.g. respiration and filtration rates), the lack of broadly applicable conversion equations currently hinders reliable comparison across bivalve populations. To facilitate improved comparative assessment amongst studies originating from disparate geographic locations, we report body size and biomass conversion equations for six invasive freshwater bivalves (or species complex members) worldwide: Corbicula fluminea, C. largillierti, Dreissena bugensis, D. polymorpha, Limnoperna fortunei and Sinanodonta woodiana, and tested the reliability (i.e. precision and accuracy) of these equations. Body size (length, width, height) and biomass metrics of living-weight (LW), wet-weight (WW), dry-weight (DW), dry shell-weight (SW), shell free dry-weight (SFDW) and ash-free dry-weight (AFDW) were collected from a total of 44 bivalve populations located in Asia, the Americas and Europe. Relationships between body size and individual biomass metrics, as well as proportional weight-to-weight conversion factors, were determined. For most species, although inherent variation existed between sampled populations, body size directional measurements were found to be good predictors of all biomass metrics (e.g. length to LW, WW, SW or DW: R2 = 0.82–0.96), with moderate to high accuracy for mean absolute error (MAE): ±9.14–24.19%. Similarly, narrow 95%–confidence limits and low MAE were observed for most proportional biomass relationships, indicating high reliability for the calculated conversion factors (e.g. LW to AFDW; CI range: 0.7–2.0, MAE: ±0.7–2.0%). Synthesis and applications. Our derived biomass prediction equations can be used to rapidly estimate the biologically active biomass of the assessed species, based on simpler biomass or body size measurements for a wide range of situations globally. This allows for the calculation of approximate average indicators that, when combined with density data, can be used to estimate biomass per geographic unit-area and contribute to quantification of population-level effects. These general equations will support meta-analyses, and allow for comparative assessment of historic and contemporary data. Overall, these equations will enable conservation managers to better understand and predict ecological impacts of these bivalves