An invasive bivalve with the potential to reconstruct chronologies of geomarkers in a large South American basin.

The Sr/Ca and 87Sr/86Sr ratios are used as natural indicators (geomarkers) in fish to reveal migratory patterns, due to significant relationships between these ratios measured in the water and in the fish calcified structures (otoliths, bones). The aim of this study was to assess the potential use of the Limnoperna fortunei shell as a proxy for monitoring the spatial and temporal variability of Sr/Ca and 87Sr/86Sr in water. These ratios were compared in water samples and bivalve shells proceeding from eight sites of four hydrogeological regions of the La Plata Basin (Argentina and Uruguay), collected in two hydrological periods (winter and summer) in order to depict the pattern of geographical and temporal variability and to evaluate the relationship between both matrices. Significant positive linear relationships were found between shell edge and water for 87Sr/86Sr (R2 = 0.96-0.97, p < 0.005) and Sr/Ca (R2 = 0.83-0.86, p < 0.05) in summer and winter. Slopes did not differ significantly from 1 (p > 0.05) for 87Sr/86Sr, while they differed from 1 for Sr/Ca in both seasons (p < 0.05), indicating that the elemental ratio would be influenced by endogenous/exogenous factors. No significant seasonal differences were found for both natural tags (p > 0.05), except for the lower Uruguay River (87Sr/86Sr) and outer estuary (Sr/Ca). These results indicate that the L. fortunei shell could be a valuable tool for monitoring spatio-temporal variations in water 87Sr/86Sr. Shell Sr/Ca shows high potential utility as a geomarker in freshwater, but additional assessments are needed to understand the impact of temperature and growth on this ratio.

MFishBT: A global database of biogeochemical tags in migratory fish.

Humans have long been fascinated by the mysteries surrounding fish migrations and addressing these complex behaviors often requires large data sets. Biogeochemical tags, including trace elements and stable isotopes, are the most accessible biomarkers for tracking fish migrations. However, access to standardized biogeochemical tag data is rarely available for migratory fish, which limits our understanding of the evolutionary origins, drivers, timing, and corridors of migration. This precludes the development of conservation strategies and the implementation of management actions. Here, we present MFishBT, a global, open-access database of Migratory Fish's Biogeochemical Tags. As of April 2023, the MFishBT contains biogeochemical records from 1,305 studies, of which 53% used element-to-calcium (E/Ca) ratios, 34% used isotopic ratios, and 13% used both. The database covers 17,413 field sampling locations (inland 47% vs. marine 53%) around the globe, comprising 490 migratory fish species of four classes, 44 orders/suborders, and 137 families. In total, 77 trace elements and 11 isotope systems were measured across various fish biological archives, including otoliths, scales, eye lenses, and vertebrae. E/Ca ratios were examined more frequently than isotopic ratios, led by Sr/Ca, Mg/Ca, Ba/Ca, and 87 Sr/86 Sr, δ13 C, and δ18 O. The MFishBT compiles 27,030, 16,222, and 2,481,714 records with biogeochemical data detected in the core, edge, and core-to-edge transects for biological archives of migratory fish. This is the most globally comprehensive open-access database on biogeochemical tags in migratory fish to date, and can serve a variety of needs in scientific research, conservation, and management. We encourage researchers to add more data sets to this database in the future. This database is released for noncommercial use only. There are no copyright restrictions, and please cite this paper when using these data, or a subset of these data, for publication.

Isotope geochemistry as a natural tag of fish in Patagonian freshwater environments: The invasive Chinook salmon case.

Patagonian aquatic environments have been invaded since the end of the last century by different species of salmonids. Knowing the natal origin and homing/straying rate of the salmonids in colonised environments is essential to understanding the dispersal mechanisms and developing management plans. In the last two decades, Chinook salmon Oncorhynchus tshawytscha showed the greatest natural dispersal capacity in Patagonia. The main goal of this study was to evaluate the environmental strontium isotope ratio (87Sr/86Sr) as a potential natural tag to infer the natal origin and ontogenetic habitat use of salmonids in Patagonia, specifically Chinook salmon. 87Sr/86Sr ratio was determined in water samples from 26 sites distributed in 14 Atlantic and Pacific basins in low and high water seasons. Environmental 87Sr/86Sr showed greater spatial than temporal variation, revealing great potential as a tool to infer the natal origin and life history of several migratory fish species in Patagonia. Otolith core-to-edge 87Sr/86Sr profiles were also analysed in 108 Chinook salmon from six basins. A cluster analysis based on the Unweighted Pair Group method (UPGMA) and Euclidean distances without prior classification grouped the sampled rivers into five main groups with significantly different (p < 0.05) isotopic ratios, sometimes integrated basins with different slopes (Atlantic or Pacific). The cluster analysis based on the natal 87Sr/86Sr period in otolith (∼natal origin) showed clear segregation between the Atlantic and Pacific samples. A mismatch between water and otolith natal 87Sr/86Sr ratio was detected in some Atlantic basins (e.g. De las Vueltas River in Santa Cruz Basin) and Pacific (e.g. Liquiñe Basin) and, which could be explained either by straying behaviours or by large geochemical variability between tributaries, within river systems. Our results showed that 87Sr/86Sr is a useful natural tag to trace the life history of migratory fishes in Patagonia, especially for invasive species such as Chinook salmon.

Essential and non-essential metals in three lowland rivers of temperate South America (Argentina): Distribution and accumulation.

BACKGROUND: Geographic distribution of essential metals on earth is largely uneven. Therefore, regional specific approaches to assess metal contents in freshwater ecosystems are mandatory. Cd, Cu, Cr, Pb, Ni, Mn and Zn concentrations were measured in water, sediments and fish tocharacterize the partitioning of these essential and non-essential metals in three river ecosystems of the Pampean Plain==. METHODS: Water, sediment and eight fish species were collected at three rivers from the Pampean Plain. After sample-specific pretreatments, Cd, Cr, Cu, Mn, Ni, Pb and Zn concentrations in water, sediment and muscle were determined in triplicate by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). Contamination (Hakanson´s index) and bioconcentration factors were calculated to assess the degree of contamination and the relationship between the matrices, while the target hazard quotient was estimated to explore the risk to human health from fish consumption. RESULTS: Water metal concentration was below detection limit in all sampled rivers. Sediments were mostly enriched by Mn (186-474 mg kg-1) followed by Zn (36.8-40.3 mg kg-1), whereas in fish, the situation was the opposite, suggesting different biogeochemical pathways and uneven bioaccumulation of these elements. The largest concentrations for all explored metals were invariably recorded in fish from the Sauce Grande River, although only Cd, Cu and Ni in sediments were highest at this site. Indeed, the bioconcentration factor showed that Cd and Zn are actively accumulated by almost all species in all sampled rivers. The Targeted Hazard Quotient based on the muscle metal concentration tissue of the edible fish species (Odontesthes bonariensis) was less than 1. CONCLUSION: None metal seemed to pose a significant risk for humans. In some sites biota-sediment concentration factors of Cd and Zn and muscle Cd, Cr, Ni, Zn and Pb levels were highest in the silurid Pimelodella laticeps, suggesting that it may be used as a sentinel species for biomonitoring programs in Neotropical fish assemblages.

Distribution and accumulation of major and trace elements in water, sediment, and fishes from protected areas of the Atlantic Rainforest.

Environmental pollution affects the quality of the natural environment where major and trace elements have been commonly found to accumulate in biotic and abiotic matrices. The purposes of this research were (1) to assess the accumulation and distribution of 24 major and trace elements in water, sediments, and muscle and gills of ten native fishes from two natural areas with different degree of protection in the Atlantic Rainforest, (2) to discuss potential origin of the elements related to the land use, and (3) to assess the human health risk for water and muscle fish consumption in general and fisher populations. Major and trace elements were determined by inductively coupled plasma mass spectrometry. Concentrations of Ag, Cu, and Se in water and Cr, Cu, Hg, Mn, Ni, and Zn in sediment were higher than the international guidelines for the aquatic biota protection. Muscle Cr, Cu, Ni, Pb, Hg, and Zn from several species (both studied areas) were above guidelines for human consumption. The bioaccumulation factor (< 6936) was higher in gills than in muscle, and indicated that Andromakhe saguazu, Andromakhe paris, Gymnogeophagus lipokarenos, and Steindachnerina biornata were macroconcentrators of Zn, and Australoheros ykeregua, G. lipokarenos, and Hemiancistrus fuliginosus were macroconcentrators of Se and Sr. The hazard index and target hazard quotient indicated that there is no risk from chronic consumption of water or fish. The results show the need to reduce the entry of pollutants into streams, paying special attention to reducing runoff in deforested areas.

Antiparasitic Derivatives of the Furoquinoline Alkaloids Kokusaginine And Flindersiamine.

We report the synthesis of 16 new compounds obtained from kokusaginine and flindersiamine, the main alkaloids isolated from the bark of Balfourodendron riedelianum. The activity of the compounds against axenic cultures of Trypanosoma cruzi epimastigtotes and trypomastigotes, as well as intracellular amastigotes, is described, together with their cytotoxic activity against three different human cell lines. The synthetic strategy for the preparation of the new compounds was based on the reactivity at the C4 position of the furoquinoline core towards nucleophiles. The new derivatives were synthesized by a Buchwald-Hartwig reaction, in most cases under green, solvent-free conditions. Compounds 1 c and 1 e displayed better in-vitro activity against trypomastigotes than benznidazole and nifurtimox (positive controls) with IC50 <4 µM. In addition, both compounds were not cytotoxic against the three human cell lines K562 (erytroleukimia), LM2 (breast cancer), and HaCat (keratinocyte). Interestingly, when evaluated against intracellular amastigotes, compound 1 c was able to significantly reduce the number of this parasite form, compared to the negative control.

Synthesis and cytotoxicity evaluation of olivacine-indole hybrids tethered by alkyl linkers.

In this work, eleven new derivatives were prepared of the alkaloid olivacine (1), which was isolated from the bark of Aspidosperma australe. These compounds (7a-k) are hybrids of olivacine and indoles or carbazole, tethered by alkyl chains of variable lengths (C-4, C-5 or C-6). Compounds 7a-k showed increased cytotoxicity towards a panel of four cell lines. The subcellular localization of olivacine and of the synthetic derivatives was studied by fluorescence microscopy. The cycles of K562 cells exposed to olivacine or compounds 7a-k were analysed by flow cytometry, and showed, for some of the new derivatives, a different profile of cell distribution among the phases of the cycle when compared to olivacine, which is indicative of lysosomal apoptosis.

Metals and metalloids in a first order stream of the Atlantic rainforest: abiotic matrices, bioaccumulation in fishes and human health risk assessment.

BACKGROUND AND AIM: Metals and metalloids have been found in several streams and rivers from the Atlantic Rainforest (ARF), one of the world´s leading biodiversity hotspot, which may represent a risk for environmental and human health. The aims of this study were: 1) to evaluate the accumulation and distribution of 24 trace elements in water, sediments and fish tissues (muscle and gills) of sixteen species from the Atlantic Rainforest, 2) to explore bioaccumulation patterns in fish tissues and abiotic matrices, and 3) to assess the impact of metal and metalloids on the human health from water and fish consumption. METHODS: Water, sediments and fish samples were collected from Ramos Stream (Misiones Province, Argentina). The concentrations of Ag, Al, As, Ba, Be, Cd, Co, Cr, Cs, Cu, Fe, Ga, Hg, Li, Mg, Mn, Ni, Pb, Se, Sr, Ti, U, V and Zn were determined by Quadrupole Inductively Coupled Plasma Mass Spectrometry. Bioaccumulation factors (BAFs) were used to evaluate bioaccumulation of metals and metalloids in relation to water and sediment. The Hazard Quotient (HQ), Hazard Index (HI) and Target Hazard Quotient (THQ, general and fisherman populations) were calculated to assess the non-carcinogenic human health risk from water and fish consumption. RESULTS: The concentrations of several elements in water and sediment were higher than the international guidelines for aquatic biota protection. Levels of As, Pb and Zn in muscle and gills were above national and international guidelines for human consumption. The bioaccumulation factors ranged from 749 to 13,029 being higher in gills than in muscle. The HQ and HI ranged from 0.001 to 0.015. The THQ for each element and total THQ values were lower than 0.1. CONCLUSION: Bioaccumulation factor suggests that several species have a moderate capacity to incorporate some metals and metalloids from the abiotic matrices. According to the HI and THQ values found, there is no risk to human health from consumption of water and fish.

Multi-matrix approach reveals the distribution of pesticides in a multipurpose protected area from the Atlantic Rainforest: potential risk for aquatic biota and human health?

The Atlantic Rainforest is among the main biodiversity hotspots in the world, the Yabotí Biosphere Reserve (YBR) being one of the most important remaining areas. Agriculture practices could lead to intensive usage of pesticides resulting in a risk to the environment and human health. Water, suspended particulate matter (SPM), sediment, and fish (Andromakhe paris and Andromakhe saguazu) samples were collected from four streams with different degrees of protection of the YBR in two periods in order to assess the distribution of 18 organochlorine pesticides. Legacy and current-use pesticides were found in the different environmental matrices of the stream headwaters in non-anthropized areas within the buffer zone that drains the intangible area. A similar occurrence pattern of pesticides was found in all matrices. Levels of DDTs (<3.63 ng/L) and endosulfans (<21.8 ng/L) in surface water were above international guidelines for the protection of aquatic life in several streams for both sampling periods. HCHs, DDTs, endosulfans, and chlorpyrifos were detected in SPM and sediments from three streams, while γ-HCH (<60.3 ng/g lipid weight), chlorpyrifos (<698 ng/g lw), p,p´-DDD (<367 ng/g lw), and α-endosulfans (<209 ng/g lw) were detected in fish muscle in several streams. Chlorpyrifos and endosulfans were associated with current use, while DDx/DDT ratios suggested an old use. The concentration of pesticides found would not represent a risk to human health; however, it highlights the need to establish better regulation and action guidelines to reduce the anthropogenic effect on natural reserves.

White mullet Mugil curema population structure from Mexico and Brazil revealed by otolith chemistry.

The white mullet Mugil curema supports several fisheries in the neotropical region; nevertheless, the population structure is still elusive. The aim of this study was to assess the presence of adult management units and nursery areas from five sampling sites throughout the Gulf of Mexico and northern Brazil using otolith microchemistry. The Li/Ca, Na/Ca, Mn/Ca, Sr/Ca, Ba/Ca and Pb/Ca ratios were measured in otolith core (juvenile stage) and edge (adult stage) (N = 131) using laser ablation-inductively coupled plasma-mass spectrometry. Several ratios were significantly different between sampling sites for core and edge (P < 0.05). For otolith edge, permutational multivariate analysis of variance showed significant differences (P < 0.05) between all sampling sites from Mexico (except between Mecoacán and Tamiahua, P > 0.05) and between Mexico (pooled samples) and Brazil. Quadratic discriminant analyses showed jackknifed classification higher in the edge (66.6% and 99.5% for Mexico and Brazil plus Mexico, respectively) than in the core (46.3% and 76.5% Mexico and Brazil plus Mexico, respectively). The two cluster analyses based on the core microchemistry (Mexico and Brazil plus Mexico) produced three main clusters, which did not coincide with catchment areas. These results support the segregation of the M. curema adult life stages among several sampling sites from Mexico and Brazil; moreover, core analysis suggested that the nursery areas did not correspond to the capture sites or adults stocks.

Otoliths as indicators for fish behaviour and procurement strategies of hunter-gatherers in North Patagonia.

This study evaluates the potential use of archaeological otoliths of Genidens barbus (Cuvier and Valenciennes) as a tool to study fish behavior and hunter-gatherers procurement strategies on the North Patagonian coast. The studied samples come from the San Antonio archaeological locality dated at ca. 1000-800 14C yr BP (Late Holocene). To assess whether exposure to fire significantly affects the otolith Sr:Ca and Ba:Ca ratios, burned and unburned modern lapilli otoliths have been analyzed by Laser Ablation Inductively Coupled Plasma Mass Spectrometry and no statistically significant differences were found between the results of both treatments. Core-to-edge chemical time series were carried out on ancient otoliths (ca. 1000 14C yr BP) in order to study the fish life history. Three amphidromous patterns were found for ancient samples. The capture environments and seasons inferred by the otolith edge chemistry and marginal increase, respectively, suggest a location in high salinity water (estuary and sea) in summer. Finally, to estimate the size of archaeological fish, a linear regression between total length and otolith length was constructed using 70 modern catfish otoliths. The size variability (358-610 mm) might indicate the use of non-selective capture techniques, probably nets, by hunter-gatherer groups.

Unravelling the stock structure of the Persian brown trout by otolith and scale shape.

The simultaneous use of the scale and otolith morphometry was assessed as a potential tool for the identification of Persian brown trout Salmo trutta stocks of the Lar Lake and five rivers from Lar Basin, Iran. Fourier coefficients (FC) and circularity, rectangularity, roundness, ellipticity and form factor shape indices (SI) were calculated for otolith and scale. Several SIs were significantly different among sites for both structures. Permutational multivariate analysis of variance revealed significant differences between several pairwise comparisons for otolith and scale (FCs and indices separately). Discriminant analysis showed otolith FCs (cross-classification rates: 25-86%) and SI (20-45%) appear to be a relatively acceptable tool to discriminate between several locations. Comparatively, the scale morphometry showed lower discriminatory power (FC = 3-65%; SI = 15-34%), with the exception of SI for Elarm River (60%), Kamardasht River (56%) and Lar Lake (75%). Cross-classification rates improved up to 100% when discriminate analysis incorporating all variables for otolith and scale was performed. The results showed a potential segregation between some water bodies, suggesting that the otolith and scale morphometry could be a useful tool to delimit S. trutta populations in relatively close freshwater environments.

Biodiversity and threats in non-protected areas: A multidisciplinary and multi-taxa approach focused on the Atlantic Forest.

Along many decades, protected environments were targeted by the scientific community for ecological research and for the collection of scientific information related to environmental aspects and biodiversity. However, most of the territory in hotspot regions with weak or even non legal protection has been left aside. These non-protected areas (NPA) could host high biodiversity values. This paper addresses how scientific effort on a NPA (CIAR) of 700 ha from the Atlantic Rain Forest, generates new information and tools for large-scale environmental and biodiversity management in NPAs. Information published during the last decade was summarized and complemented with subsequent novel data about biodiversity (new species, first records, DNA and chemical analyses, etc.). The results showed: 1 new genus (arachnid), 6 new species and several putative new species (fish and arthropod), 6 vulnerable species (bird and mammal) and 36 first records for Argentina (fish, arthropod, platyhelminth and fungi). When compared with protected natural areas of the same biome, the CIAR showed highly valuable aspects for fauna and environment conservation, positioning this NPA as a worldwide hotspot for some taxa. Indeed, when compared to international hotspots in a coordinated Malaise trap program, the CIAR showed 8,651 different barcode index numbers (∼species) of arthropods, 80% of which had not been previously barcoded. Molecules like Inoscavin A, with antifungal activity against phytopathogens, was isolated for the first time in Phellinus merrillii fungi. The study of major threats derived from anthropic activities measured 20 trace elements, 18 pesticides (i.e. endosulfans, chlorpyrifos, DDTs, HCHs) and 27 pharmaceuticals and drugs (i.e. benzoylecgonine and norfluoxetine) in different biotic and abiotic matrices (water, sediment, fish and air biomonitors). This integrated data analysis shows that biodiversity research in NPA is being undervalued and how multidisciplinary and multi-taxa surveys creates a new arena for research and a pathway towards sustainable development in emerging countries with biodiversity hotspots.

Isolation and Antimacrofouling Activity of Indole and Furoquinoline Alkaloids from 'Guatambú' Trees (Aspidosperma australe and Balfourodendron riedelianum).

In this work, the antifouling activity of five alkaloids, isolated from trees of the Atlantic rainforest, was studied. The tested alkaloids were olivacine (1), uleine (2) and N-methyltetrahydroellipticine (3) from Aspidosperma australe ('yellow guatambú') and the furoquinoline alkaloids kokusaginine (4) and flindersiamine (5) from Balfourodendron riedelianum ('white guatambú'). All these compounds can be isolated from their natural sources in high yields in a sustainable way. The five compounds were subjected to laboratory tests (attachment test of the mussel Mytilus edulis platensis) and field trials, by incorporation into soluble matrix paints, and 45 days of exposure of the painted panels in the sea. The results show that compound 3 is a very potent antifoulant, and that compounds 4 and 5 are also very active, while compounds 1 and 2 did not show any significant antifouling activity. These results open the way for the development of environmentally friendly antifouling agents, based on abundant and easy-to-purify compounds that can be obtained in a sustainable way.

Distribution and bioaccumulation of 12 trace elements in water, sediment and tissues of the main fishery from different environments of the La Plata basin (South America): Risk assessment for human consumption.

The concentration of Ag, As, Cd, Cu, Cr, Hg, Ni, Pb, Se, U, V, and Zn was analyzed in water, sediment, and different organs of Prochilodus lineatus (muscle, liver and gill) in three most commercially important catch areas along La Plata Basin, namely High Paraná River (HPR), Middle Paraná River (MPR) and Río de la Plata Estuary (RPE). The concentration of As, Cu and Zn (RPE) and Se (HPR) in water and As (RPE), Ni (HPR and MPR), Cu and Cr (all sites) in sediments exceeded the limits considered as hazardous for aquatic life. With the exception of Se (sediment-liver) and Pb (sediment-liver and sediment-gill), it was not observed a significant correlation between the element concentration in tissues and that found in water and sediment. No correlation was found between the size fish and element concentrations. Liver appeared to be the main storage tissue of trace elements and was classified as a macroconcentrator of Ag, Cu, Hg and Zn. Levels of trace elements in muscle of streaked prochilod were below recommended maximum levels established by national and international guidelines. According to Target Hazard Quotient (THQ), the consumption of muscle of P. lineatus from three sampling sites did not present toxicological risk for general and fishermen populations. Multivariate analyses suggest that the three groups studied remain with an important degree of geographical segregation, indicating that regulations should be revised according to the presence of contaminants in the different fishing areas.

Arsenic, selenium, and metals in a commercial and vulnerable fish from southwestern Atlantic estuaries: distribution in water and tissues and public health risk assessment.

The anadromous catfish Genidens barbus is a vulnerable and economically important species from the Southwestern Atlantic Ocean. Concentrations of As, Co, Fe, Se, and Zn were determined in water and muscle, gill, and liver of catfish from two southwestern Atlantic estuaries (Brazil and Argentina) and health risk via fish consumption was evaluated. High spatial variability was observed in the metals, As, and Se distribution for both estuaries. Considering all tissues, element concentrations (mg/kg, wet weight) were As = 0.41-23.50, Co = 0.01-2.9, Fe = 2.08-773, Se = 0.15-10.7, and Zn = 3.97-2808). Most of the trace elements tended to be higher in Brazil than in Argentina, except for Co, Fe, Se, and Zn in liver and Fe and Co in muscle and gill, respectively. Arsenic accumulation order was muscle > liver ≥ gill. Only As (muscle) was above the maximum recommended by international guidelines at both estuaries. The target hazard quotient ranged from 0.10 to 1.58, suggesting that people may experience significant health risks through catfish consumption. Supposing that the inorganic/toxic As ranged between 1 and 20% of the total, the recommended maximum intakes per capita bases were 6.1-95 and 8.4-138 kg/year (wet weight) for Brazil and Argentina, respectively. Carcinogenic risk for As intake was within the acceptable range but close to the recommended limit (> 10-4). These results highlights the importance of quantifying the As species in catfish muscle in order to generate more reliable risk estimates.

Pharmaceuticals, illicit drugs and their metabolites in fish from Argentina: Implications for protected areas influenced by urbanization.

Because an understanding of aquatic bioaccumulation of human pharmaceuticals in Latin America is limited, this area was recently identified as a priority environmental quality research need. We examined bioaccumulation of twenty-seven pharmaceuticals, illicit drugs and their metabolites in muscle, liver and gills of multiple fish species (Rhamdia quelen, Hypostomus commersoni, Hoplias lacerdae, Prochilodus lineatus) from an urban river receiving wastewater discharges (Paraná) and a lotic system (Acaraguá) without direct wastewater sources, which runs through a protected area. All samples were analyzed using isotope-dilution liquid chromatography-tandem mass spectrometry. Caffeine, which was detected up to 13 µg/kg, and antibiotics were consistently detected in all fish. Among antibiotics, erythromycin was ubiquitous (0.7-5.6 µg/kg) but its tissue concentrations were lower than levels of sulfamethoxazole, sulfathiazole and trimethoprim (0.9-5.5 µg/kg), which are used in human medicine, aquaculture and livestock. Erythromycin bioaccumulation in fish is reported here from Argentina for the first time, though levels of antibiotics in edible muscles of these species were lower than the maximum residue limits for human consumption. We observed norfluoxetine, the primary active metabolite of the antidepressant fluoxetine, ranging from 1.1-9.1 µg/kg in fish. We further identified benzoylecgonine, a primary metabolite of cocaine, in fish from both study systems, representing the first observation an illicit drug or associated metabolites bioaccumulation in aquatic life from Argentina. Interestingly, high pharmaceutical levels were observed in fish from the Acaraguá river suggesting their transport into the protected area, from the surrounding lands. Though fish from the Paraná river were sampled near WWTP discharges, pharmaceutical concentrations may have been reduced by hydrological and other environmental conditions, and biological differences among species. These findings, which observed bioaccumulation of select pharmaceuticals, their metabolites and illicit drugs in wild fish sampled inside a protected area, highlight the importance of developing an advanced understanding of urban influences on inland protected watersheds.

A continental-wide molecular approach unraveling mtDNA diversity and geographic distribution of the Neotropical genus Hoplias.

With an estimate of around 9,000 species, the Neotropical region hosts the greatest diversity of freshwater fishes of the world. Genetic surveys have the potential to unravel isolated and unique lineages and may result in the identification of undescribed species, accelerating the cataloguing of extant biodiversity. In this paper, molecular diversity within the valuable and widespread Neotropical genus Hoplias was assessed by means of DNA Barcoding. The geographic coverage spanned 40 degrees of latitude from French Guiana to Argentina. Our analyses revealed 22 mitochondrial lineages fully supported by means of Barcode Index Number, Automatic Barcode Gap Discovery and phylogenetic analyses. This mtDNA survey revealed the existence of 15 fully supported mitochondrial lineages within the once considered to be the continentally distributed H. malabaricus. Only four of them are currently described as valid species however, leaving 11 mitochondrial lineages currently "masked" within this species complex. Mean genetic divergence was 13.1%. Barcoding gap analysis discriminated 20 out of the 22 lineages tested. Phylogenetic analyses showed that all taxonomically recognized species form monophyletic groups. Hoplias malabaricus sensu stricto clustered within a large clade, excluding the representatives of the La Plata River Basin. In the H. lacerdae group, all species but H. curupira showed a cohesive match between taxonomic and molecular identification. Two different genetic lineages were recovered for H. aimara. Given the unexpected hidden mitochondrial diversity within H. malabaricus, the COI sequence composition of specimens from Suriname (the type locality), identified as H. malabaricus sensu stricto, is of major importance.

Migration and brackish environment use of Prochilodus lineatus (Characiformes: Prochilodontidae) inferred by Sr:Ca ratio transects of otolith

The streaked prochilod, Prochilodus lineatus, represents the most important fishery in the La Plata Basin (South America). Our objective was to analyze brackish environment use by the streaked prochilod captured from Paraná and Uruguay rivers. To accomplish this, lapillus otolith sections were analyzed for Sr:Ca with laser ablation-inductively coupled plasma-mass spectrometry (LA ICP-MS) to infer habitat use of fish. To the interpretation of transects, a threshold that represents the transition between freshwater and brackish environments was calculated using the Sr:Ca ratio of the otolith edge of specimens captured in the first section of the La Plata Estuary (salinity ≥ 0.5 PSU). The percentage of fish using the estuary was higher in the Paraná (37%) than the Uruguay River (5%). Change-point analysis showed that fish entered the estuary between 1 and 3 times throughout life at a wide range of ages (0-15 years). These incursions had no obvious periodicity. This information should be integrated into future management actions, which should also be specific to each area since migration patterns differ between the major rivers of the basin.(AU)

El sábalo, Prochilodus lineatus, representa la pesquería más importante en la Cuenca del Río de la Plata (Sudamérica). Nuestro objetivo fue analizar el uso del hábitat estuarino del sábalo proveniente de los ríos Uruguay y Paraná. Para esto, se analizó la relación Sr:Ca en secciones de otolitos lapilli por ablación láser acoplada a espectrometría de masas con fuente de plasma de acoplamiento inductivo (LA ICP-MS) para inferir el uso de hábitat. Para interpretar las transectas, un umbral que representa la transición entre los ambientes de agua dulce y estuarino, fue calculado usando la relación Sr:Ca del borde del otolito de especímenes capturados en la primera sección del estuario del Plata (salinidad ≥0.5 UPS). El porcentaje de peces que usaron el estuario fue más elevado para el Paraná (37%) en relación al Uruguay (5%). El análisis de cambio puntual mostro que los individuos ingresan al estuario entre 1 a 3 veces a lo largo de la vida en un amplio rango de edades (0-15 años). Las incursiones no mostraron una periodicidad notoria. Esta información debería integrarse a futuras acciones de manejo que deberían ser específicas para cada área considerando los patrones de migración que difieren entre los grandes ríos de la Cuenca.(AU)