Effects of osmotic and thermal shock on the invasive aquatic mudsnail Potamopyrgus antipodarum: Mortality and physiology under stressful conditions

Invasive freshwater species, such as the exotic mollusc Potamopyrgus antipodarum (New Zealand mudsnail), can frequently survive under harsh conditions, including brackish and hypoxic environments. We experimentally assessed the effects of osmotic (0, 10, 20, 25 and 30 psu) and thermal (20 °C) shock on mortality, activity and physiology of P. antipodarum collected at Capitol Lake, Olympia, Washington, USA, during winter and spring seasons when environmental temperature was 5 and 10 °C respectively. We measured standard metabolic rate and enzymatic activities (malate dehydrogenase, lactate dehydrogenase, alanopine dehydrogenase) in snails after a 10-day acclimation period at high salinity. Significantly higher mortalities were observed at higher salinities; the strongest effects occurred on snails collected at the end of winter, and exposed to 30 psu and 20 °C (100% mortality in 3 days). When snails were collected during the spring, 100% mortality was observed after 40 days at 30 psu and 20 °C. Standard metabolic rates were significantly lower when snails were exposed to salinities of 25 and 30 psu, even after 10 days of acclimation. Enzymatic activities showed small but significant declines after 10 days at 30 psu reflecting the declines observed in overall metabolism. The physiological tolerances to temperature and salinity displayed by this population of P. antipodarum make its eradication from Capital Lake difficult to achieve.Fil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Thuesen, Erik V.. The Evergreen State College; Estados Unido

Ventajas y límites de la variabilidad morfofisiológica para el establecimiento, la colonización y la expansión del bivalvo invasor Limnoperna fortunei en Sudamérica

La variabilidad fenotípica, tanto basada en plasticidad fenotípica como en diversidad genética, puede tener una gran importancia durante el proceso de invasión de las especies exóticas. Limnoperna fortunei (Dunker, 1857) fue introducido en Sudamérica alrededor de 1990, en el estuario del Río de la Plata, Argentina, desde donde se expandió rápidamente hasta abarcar prácticamente toda esta cuenca y otras aledañas. Sin embargo, algunos ambientes no han sido colonizados y, presumiblemente, la supervivencia de esta especie se vio afectada por distintos factores ambientales como los sólidos en suspensión, la salinidad, y la contaminación. L. fortunei evidenció una alta variabilidad genética y morfológica, mostrando una distribución fuertemente afectada por las actividades humanas y por sus vectores de dispersión. El grado de variabilidad fenotípica estaría jugando un papel fundamental en su establecimiento, o no, en los diferentes ambientes. Las variaciones morfológicas y metabólicas, incluyendo cambios en la tasa de crecimiento, desarrollo de órganos internos o cambios en la tasa de filtrado y respiración en áreas límite de su distribución o bajo condiciones ambientales extremas, permitirían explicar, junto con otras variables como la presencia de vectores de dispersión, el patrón de distribución actual

Benefícios e limites da variabilidade morfofisiológica para o estabelecimento, colonização e expansão do bivalve invasor Limnoperna fortunei na América do Sul

Phenotypic variability, both based on phenotypic plasticity and genetic diversity, can be a main factor affecting the invasion process of alien species. Limnoperna fortunei (Dunker 1857) was introduced in South America around 1990, in the Río de la Plata estuary, Argentina, from where it spread swiftly to cover most of the basin and other smaller watersheds. However, some environments have not been colonized and, presumably, the survival of this species was affected by different environmental factors such as suspended solids, salinity, and pollution. L. fortunei showed high genetic and morphological variability, showing a distribution strongly affected by human activities and its dispersal vectors. The degree of phenotypic variability would be playing a main role in its establishment, or not, in the different environments. Morphological and metabolic variations, including changes in the growth rate, development of internal organs or changes in the rate of filtration and respiration in border areas of its distribution or under extreme environmental conditions, would allow to explain, together with other variables such as the presence of dispersal vectors, the current distribution pattern.La variabilidad fenotípica, tanto basada en plasticidad fenotípica como en diversidad genética puede tener una gran importancia durante el proceso de invasión de las especies exóticas. Limnoperna fortunei (Dunker, 1857) fue introducido en Sudamérica alrededor de 1990, en el estuario del Río de la Plata, Argentina, desde donde se expandió rápidamente hasta abarcar prácticamente toda esta cuenca y otras aledañas. Sin embargo, algunos ambientes no han sido colonizados y, presumiblemente, la supervivencia de esta especie se vio afectada por distintos factores ambientales como los sólidos en suspensión, la salinidad, y la contaminación. L. fortunei evidenció una alta variabilidad genética y morfológica, mostrando una distribución fuertemente afectada por las actividades humanas y por sus vectores de dispersión. El grado de variabilidad fenotípica estaría jugando un papel fundamental en su establecimiento, o no, en los diferentes ambientes. Las variaciones morfológicas y metabólicas, incluyendo cambios en la tasa de crecimiento, desarrollo de órganos internos o cambios en la tasa de filtrado y respiración en áreas límite de su distribución o bajo condiciones ambientales extremas, permitirían explicar, junto con otras variables como la presencia de vectores de dispersión, el patrón de distribución actual.A variabilidade fenotípica, tanto baseada na plasticidade fenotípica quanto na diversidade genética, pode ser um dos principais fatores que afetam o processo de invasão de espécies exóticas. Limnoperna fortunei (Dunker, 1857) foi introduzido na América do Sul por volta de 1990, no estuário do Río de la Plata, Argentina, de onde se espalhou rapidamente para cobrir a maior parte da bacia e outras bacias hidrográficas menores. No entanto, alguns ambientes não foram colonizados e, presumivelmente, a sobrevivência desta espécie foi afetada por diferentes fatores ambientais, como sólidos em suspensão, salinidade e poluição. L. fortunei apresentou alta variabilidade genética e morfológica, apresentando uma distribuição fortemente afetada pelas atividades humanas e seus vetores de dispersão. O grau de variabilidade fenotípica estaria desempenhando um papel fundamental no seu estabelecimento, ou não, nos diferentes ambientes. Variações morfológicas e metabólicas, incluindo alterações na taxa de crescimento, desenvolvimento dos órgãos internos ou alterações na taxa de filtração e respiração em áreas fronteiriças de sua distribuição ou sob condições ambientais extremas, permitiriam explicar, em conjunto com outras variáveis ​​como a presença de vetores de dispersão, o padrão de distribuição atual

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

Environmental impacts of the introduced bivalve, limnoperna fortune: trophic interactions and effects on fish larvae

El objetivo de esta tesis es estudiar el impacto de las velígeras del bivalvo invasor Limnoperna fortunei en dieta de las más abundantes larvas de peces de los ríos y ambientes marginales de la cuenca del Río de la Plata. De los 25 taxones de peces registrados, 18 tenían velígeras de L. fortunei en su tracto digestivo, incluyendo los Characiformes y Siluriformes más abundantes de la cuenca. De las 825 larvas con contenido estomacal, 135 (16%) consumieron exclusivamente larvas de L. fortunei, y el 20% (169 peces) tuvieron L. fortunei y algunas otra presa. La frecuencia y biomasa relativas de velígeras de L. fortunei difirió fuertemente durante el desarrollo larval. En protolarvas y mesolarvas, las velígeras representaron el 30-35% del contenido del intestino, mientras que en metalarvas representaron sólo el 3%. Experimentalmente se observó que las protolarvas y mesolarvas de P. lineatus consumieron velígeras casi exclusivamente (88-90% en términos numéricos y de biomasa, respectivamente) cuando este ítem fue ofrecido en alta concentración, mientras que en metalarvas las velígeras solo representaron el 16% del alimento consumido. Las proporciones de velígeras en el contenido estomacal fueron siempre superiores a las suministradas en la dieta. Las larvas alimentadas con una dieta enriquecida en velígeras crecieron significativamente más (tanto en peso como en largo) que las alimentadas con las otras dietas. Concluimos que este nuevo y abundante recurso alimenticio tiene un impacto importante en la supervivencia y el crecimiento de P. lineatus y probablemente en otras especies de peces.The aim of this work is to study the impact of veligers of the exotic bivalve Limnoperna fortunei on the diets of the more abundant larval fish in the Río de la Plata basin and associated lentic environments. Of the 25 fish taxa collected, 18 had veligers of L. fortunei in their guts incluiding the more abundant Characiformes and Siluriformes. Of the 825 feeding larvae recorded, 135 (16%) fed exclusively on L. fortunei, and 20% (169 fishes) had L. fortunei and some other prey. The relative frequency and biomass contribution of L. fortunei larvae differed strongly in fishes of different developmental stage. In protolarvae and mesolarvae, veligers accounted for 30–35% of the gut contents. In metalarvae, veligers accounted for only 3%. Experiments show that protolarvae and mesolarvae of Prochilodus lineatus consumed veligers almost exclusively (88-90%, both in numbers and in biomass) when offered prey enriched in veligers, whereas for metalarvae veligers represented only 16.0% of the food consumed. Proportions of veligers in gut contents were always higher than those in the experimental diet. Larvae fed a veliger-enriched diet grew to a significantly larger size than larvae fed the other two diets. We anticipate that this new and abundant food resource has an important impact on the survival and growth of P. lineatus and probably othes fish species.Fil:Paolucci, Esteban Marcelo. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Physiological and morphological assessments suggest opposite structural allocation strategies between closely related invasive clams

Respiration is a central physiological function related to the rates of energy acquisition, transformation, and use by organisms, while allometric relationships provide insight into patterns of allocation of that energy. To assess life strategy differences between closely related invasive species, we measured oxygen consumption rates, tissue mass, shell mass, and gill area of Corbicula fluminea and Corbicula largillierti clams. We compared patterns of metabolic scaling between the two species using model II regressions. Although oxygen consumption rates were strongly associated with gill area in both species, C. fluminea had consistently higher metabolic rates, shell thickness, and shell mass, but a lower tissue-to-shell mass ratio, than C. largillierti. These differences were more marked among small individuals. Our results suggest opposite structural allocation strategies between the two species. Corbicula fluminea invests more energy in the development of thicker shells in early life stages, which can be subsidized by higher metabolic rates than C. largillierti. By contrast, C. largillierti allocates more energy to tissue mass production. These differences may play a role in explaining contrasting competitive and colonization abilities and geographical distribution patterns between both species in invaded areas.Fil: Hünicken, Leandro Andrés. 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. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidad Nacional del Comahue. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". - Provincia de Río Negro. Ministerio de Agricultura, Ganadería y Pesca. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni". Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet Centro Nacional Patagónico. Centro de Investigación Aplicada y Transferencia Tecnológica en Recursos Marinos "Almirante Storni"; ArgentinaFil: Sylvester, Francisco. 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: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Agua de lastre: Legislación y nuevos tratamientos para prevenir la introducción de especies exóticas

En virtud de la implementación de medidas estrictas por parte de los Estados y las exigencias de la Organización Marítima Internacional para prevenir la introducción de especies exóticas, la aplicación de nuevas tecnologías y el análisis de riesgo son instrumentos fundamentales para dar cumplimiento a los nuevos estándares.Fil: Ron, Leila. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; ArgentinaFil: Correa, Nancy. Ministerio de Defensa. Armada Argentina. Servicio de Hidrografía Naval; ArgentinaFil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Metabolic response to increasing environmental temperature in the invasive mussel Limnoperna fortunei

Plasticity and variability of morphological and physiological traits are common characteristics that allow invasive species to survive, establish and spread to new environments. In order to study the metabolic response of the invasive mussel Limnoperna fortunei (Dunker) (Mytilidae), which has spread through South America and Asia, oxygen consumption was measured under three different acclimation temperatures (18, 22 and 27°C). After an acclimation period of at least 7 days, oxygen consumption was measured and analysed as functions of length and mass. Biochemical composition was also investigated on specimens collected under natural conditions. Environmental scanning electron microscopy determined that the elemental composition and crystalline structure of the shells were normal as described for L. fortunei previously. Average oxygen consumption per mussel was 1.63 ± 0.12 μmol O2 h−1 for an average ash-free dry weight (AFDW) of 58.7 ± 3.0 mg. The average standard metabolic rate (SMR) per mussel was 14.94 ± 1.30, 30.04 ± 3.38, and 47.10 ± 3.54 μmol O2 gAFDW−1 h−1, at 18, 22 and 27°C, respectively. Significant higher SMR values were recorded at 27°C than at lower temperatures. This metabolic response allows L. fortunei to survive, reproduce and spread across a wide range of habitats, including tropical and subtropical environments in South America.Fil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Ron, Leila. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Thuesen, Erik V.. The Evergreen State College; Estados Unido

Native fish larvae take advantage of introduced mussel larvae: field evidence of feeding preferences on veligers of the introduced freshwater bivalve Limnopernafortunei

Previous work has shown that the invasive bivalve Limnoperna fortunei has had a measurable impact on local food webs, but knowledge of the trophic interactions involved is still very limited. On the basis of samples collected along the lower Paraguay-middle Parana´ rivers, we studied the feeding behavior and selectivity of larval fish, with emphasis on veligers of the introduced bivalve L. fortunei. Among feeding larvae (i.e., without a yolk sac), 16.5% had only Limnoperna veligers in their guts, while 15.6% had veligers and some other prey. Half of the fish taxa recorded (8 out of a total of 16) consumed Limnoperna veligers. The Paraguay and Parana´ rivers differed strongly in the proportions of fish larvae that consumed veligers: 14 and 68%, respectively. This difference paralleled the availability of veligers in the water column, which was significantly lower in the Paraguay (0.8 ± 0.5 ind. l-1 ) than in the Parana´ River (5.5 ± 2.3 ind. l-1 ). Conversely, cladocerans, originally the staple food of fish larvae, were more abundant in the Paraguay (consumed by 48% of the individuals) than in the Parana´ River (26%). These results indicate that, when widely available, Limnoperna veligers largely replace the original prey of fish larvae, especially in their younger stages (protolarvae).Fil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Almada, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentina. Ministerio de Seguridad. Prefectura Naval Argentina; ArgentinaFil: Cataldo, Daniel Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Boltovskoy, Demetrio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin

Effects of El Niño-Southern Oscillation (ENSO) on the reproduction of migratory fishes in a large South American reservoir

The ENSO (El Niño-Southern Oscillation) phenomenon affects, through climate teleconnections, hydrometric variables of water bodies worldwide, influencing biota communities. The aim of this work is to analyze ENSO effects on water discharge, water level, cyanobacterial blooms and, consequently, on the reproduction of migratory fishes with high-frequency monitoring of ichthyoplankton data from Salto Grande, a large South American reservoir. Two highest peaks of ichthyoplankton density were observed; the first one (2015–2016) occurred during a very strong El Niño event, while the second one (2019–2020) was preceded by weak El Niño events that lasted 18 months. These results suggest that ichthyoplankton abundance may be affected by the intensity and temporal extent of the episodes. In contrast, mean fish larval and egg densities were reduced by 65% and 85%, respectively during La Niña periods. Cross-correlation function (CCF) analysis indicates that water discharge, water level, and ichthyoplankton abundance were positively related to the Oceanic Niño Index, while cyanobacteria showed an inverse relationship. Cyanobacterial density increased by 574% during La Niña compared with El Niño events. Based on an uninterrupted monitoring of ichthyoplankton over 11 years, it seems reasonable to consider ENSO as a predictive tool for the intensity of reproductive activity of migratory fishes.Fil: Cataldo, Daniel Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; ArgentinaFil: Leites, Valentín. Comisión Técnica Mixta de Salto Grande; ArgentinaFil: Bordet, Facundo. Comisión Técnica Mixta de Salto Grande; ArgentinaFil: Paolucci, Esteban Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin