Limnological Review

24 pages, 935 KB

Open AccessReview

Inventory of Metazoan Parasites Associated with Anostomids in South America

by Wallas Benevides Barbosa de Sousa, Maria Fernanda Barros Gouveia Diniz and Fabio Hideki Yamada

Limnol. Rev. 2026, 26(1), 11; https://doi.org/10.3390/limnolrev26010011 - 22 Mar 2026

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Anostomidae is one of the most diverse families within the order Characiformes and is widely distributed across the river basins of the Neotropical region. Anostomids are known to host a rich diversity of metazoan parasites, including ectoparasites, such as monopisthocotylans, and endoparasites, such [...] Read more.

Anostomidae is one of the most diverse families within the order Characiformes and is widely distributed across the river basins of the Neotropical region. Anostomids are known to host a rich diversity of metazoan parasites, including ectoparasites, such as monopisthocotylans, and endoparasites, such as nematodes, cestodes, and digeneans. The present study aims to develop an inventory of metazoan parasites recorded in fish of the Anostomidae family. A bibliographic review of metazoan parasite species in anostomids was conducted, using searches in different databases. This bibliographic review was complemented with information from books and book chapters on ictioparasitology. The data were compiled until January 2025. Based on the review, 191 taxa (126 are described at the species level and 65 were identified only to the genus level or higher taxonomic categories) of metazoan parasites associated with anostomid fishes were found. Monopisthocotyla and Nematoda were the taxonomic groups with the most parasitic associations at the species level, with 31 and 30 species, respectively. This study presents a comprehensive and updated inventory of metazoan parasites associated with fish from the family Anostomidae, covering over 170 years of research (1850–2025). This survey highlights the importance of anostomids as hosts for a rich parasitic fauna. Full article

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26 pages, 1097 KB

Open AccessReview

Public Health Risks of Pathogenic Bacteria in Freshwater Bodies: A Review of Quantitative Microbial Risk Assessment Approaches and Applications

by Manu Priya, Shvetambri Jasrotia and Akebe Luther King Abia

Limnol. Rev. 2026, 26(1), 10; https://doi.org/10.3390/limnolrev26010010 - 14 Mar 2026

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Abstract

Freshwater ecosystems play an important role in human survival, ecosystem functioning, and biodiversity conservation, yet industrialisation and urbanisation dump over 80% of untreated sewage into them. This inadequate wastewater management leads to enteric pathogens like Escherichia coli, Salmonella, Shigella, Campylobacter [...] Read more.

Freshwater ecosystems play an important role in human survival, ecosystem functioning, and biodiversity conservation, yet industrialisation and urbanisation dump over 80% of untreated sewage into them. This inadequate wastewater management leads to enteric pathogens like Escherichia coli, Salmonella, Shigella, Campylobacter, Vibrio cholerae, Pseudomonas aeruginosa, and Legionella pneumophila that are responsible for a wide range of waterborne human diseases globally with extensive morbidity and mortality. The World Health Organization (WHO) estimates that at least 2 billion individuals drink water contaminated with pathogens, resulting in illnesses like cholera, dysentery, and diarrhoea, and approximately 50,000 diarrheal deaths annually. Classical epidemiology approaches are the basis for determining disease burden in public health, but they are limited in their capacity to predict future health risks. Quantitative microbial risk assessment (QMRA) addresses this by estimating the potential health risks of any exposure to microbial pathogens in any environment using four key elements, which include the identification of the microbial hazards, human exposure to the hazard through diverse activities, dose–response relationships, and the estimated risk of the infection. This review summarises information on freshwater pathogens, their occurrence, sources and health implications. The methodological approaches of QMRA in freshwater systems are reviewed with examples drawn from recreational activities, drinking water, and wastewater-impacted environments. Global QMRA studies indicate a wide range of infection risk estimates, reflecting differences in water sources, pathogens, and exposure conditions. Thus, QMRA is known to be a valuable public health tool for freshwater ecosystems, linking microbial contamination dynamics to health risk estimates that support proactive management and policy-relevant decision-making. Full article

(This article belongs to the Special Issue Freshwater Microbiology and Public Health)

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12 pages, 1344 KB

Open AccessArticle

Allelopathic Interference of the Cyanobacterium Raphidiopsis raciborskii Exudates on Photosynthetic Traits of Photosynthesizing Microorganisms

by Camila Nader, Maria Cecília Miotto, Carlos Yure B. Oliveira and Leonardo R. Rörig

Limnol. Rev. 2026, 26(1), 9; https://doi.org/10.3390/limnolrev26010009 - 13 Mar 2026

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Abstract

Raphidiopsis raciborskii (formerly Cylindrospermopsis raciborskii) is a bloom-forming cyanobacterium that employs the production of toxins and other secondary metabolites as a competitive and allelopathic strategy. This study evaluated the effects of exudates from R. raciborskii cultivated under three nitrogen-to-phosphorus (N:P) ratios on [...] Read more.

Raphidiopsis raciborskii (formerly Cylindrospermopsis raciborskii) is a bloom-forming cyanobacterium that employs the production of toxins and other secondary metabolites as a competitive and allelopathic strategy. This study evaluated the effects of exudates from R. raciborskii cultivated under three nitrogen-to-phosphorus (N:P) ratios on the photosynthetic performance of Limnothrix sp. (cyanobacterium), Chlorella sp. (green algae), and Raphidocelis subcapitata (green algae), using pulse-amplitude-modulated (PAM) fluorometry. Rapid light curves (rETR) obtained under different N:P ratios and across the three target species exhibited similar response patterns. Likewise, effective quantum yield (ΦPSII), regulated (Y(NPQ)) and non-regulated (Y(NO)) energy dissipation showed comparable profiles among treatments after 24 h of exposure. Overall, the results of the present study indicate that, within the 24 h exposure period and based on the fluorescence parameters measured, exudates produced by R. raciborskii under the tested nutrient conditions did not cause measurable alterations in the photosynthetic performance of the three evaluated species. Full article

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13 pages, 3772 KB

Open AccessCommunication

Spatial Distribution and Composition of Solid Waste Pollution Along the Banks of the Amazon River, Brazil

by Gabriel dos Anjos Guimarães, Gysele Maria Morais Costa, Isreele Jussara de Azevedo Rodrigues, Manoel Henrique de Souza Neto, Gustavo Frigi Perotti, Bruno Sampaio Sant’Anna and Gustavo Yomar Hattori

Limnol. Rev. 2026, 26(1), 8; https://doi.org/10.3390/limnolrev26010008 - 5 Mar 2026

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Abstract

Pollution from solid waste results mainly from improper disposal and inadequate waste management, causing environmental degradation and risks to human health. This study characterized solid waste pollution along the left bank of the Amazon River within the urban segment of Itacoatiara, Brazil. Eleven [...] Read more.

Pollution from solid waste results mainly from improper disposal and inadequate waste management, causing environmental degradation and risks to human health. This study characterized solid waste pollution along the left bank of the Amazon River within the urban segment of Itacoatiara, Brazil. Eleven sampling points were established across upstream, midstream and downstream sections. Solid waste was present at densities ranging from 0 to 0.65 items·m⁻², with a mean density of 0.15 ± 0.14 items·m⁻². Higher concentrations were observed in the midstream sections of the left bank (0.21 ± 0.16 items·m⁻²), and statistical analyses showed significant differences among sections. Plastics predominated among all materials (0.50 ± 0.60 items·m⁻²), and statistical analyses showed significant differences among the types of solid waste, with fragments mainly originating from bags, bottles, and fibers. Plastics were recorded in most sampling sections, with particularly high abundance in the midstream sections of the river (0.98 ± 0.80 items·m⁻²) and statistical analyses showed significant differences among sections and across material types. According to the general index and the clean coast index, sampling areas ranged from “clean” to “extremely dirty”, with midstream sections most impacted. The plastic abundance index indicated high plastic contamination, and hazardous waste was more frequent in the upstream and midstream sections. The environmental status index classified all sections as both “good” and “bad”, indicating compromised environmental quality and ecological integrity. These results show human pressure on the Amazon River banks and degraded environmental quality, supporting waste management policies, mitigation, monitoring, and environmental education to protect ecosystems and reduce risks to riverside communities. Full article

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14 pages, 3283 KB

Open AccessArticle

Growth of Chrysopogon zizanioides in Floating Treatment Wetlands with Different Substrates for the Remediation of an Urban River

by Luis Alfredo Hernández-Vásquez, Mauricio Rojas-Ascensión, Sergio Reyes Rosas, Rubén Daniel Hernández Cruz, Miguel Ángel Vega-Ortega, Gregorio Hernández-Salinas, Marco Antonio Benítez-Espíndola and Luis Carlos Sandoval Herazo

Limnol. Rev. 2026, 26(1), 7; https://doi.org/10.3390/limnolrev26010007 - 20 Feb 2026

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Abstract

Urban river degradation demands remediation strategies that are both environmentally sustainable and technically feasible. This study evaluated the performance of Floating Treatment Wetlands (FTWs) vegetated with Chrysopogon zizanioides (vetiver) and incorporating four substrate configurations: leaf litter (LL), red volcanic rock (RVR), corn cobs [...] Read more.

Urban river degradation demands remediation strategies that are both environmentally sustainable and technically feasible. This study evaluated the performance of Floating Treatment Wetlands (FTWs) vegetated with Chrysopogon zizanioides (vetiver) and incorporating four substrate configurations: leaf litter (LL), red volcanic rock (RVR), corn cobs (CC), and a composite mixture of all three, for the rehabilitation of the “Paseo de Los Ahuehuetes” River in Veracruz, Mexico. Over a 182-day monitoring period, in situ water quality parameters and plant growth responses were systematically assessed. The results indicate that substrate selection is a decisive design factor governing the establishment and development of C. zizanioides in FTWs. Among the substrates tested, LL exhibited the most favorable performance, achieving the highest plant survival (82%), enhanced shoot elongation (71.5 ± 12.1 cm), greater root development (49.7 ± 10.0 cm), and the highest relative growth rate (0.028 g g⁻¹ d⁻¹), with statistically significant differences (p < 0.05) compared to CC. Additionally, localized improvements in water quality within the FTW zone were observed, including an increase in dissolved oxygen (2.07%) and a reduction in total dissolved solids (5.65%), likely associated with intensified rhizospheric processes. Overall, these findings identify leaf litter as a low-cost, locally available, and environmentally sustainable substrate that enhances vetiver establishment in FTWs. The study provides practical, evidence-based criteria for the design of nature-based phytoremediation systems aimed at the restoration of urban river ecosystems. Full article

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27 pages, 6788 KB

Open AccessArticle

From Expert-Based Evaluation to Data-Driven Modeling: Performance-Based Flood Susceptibility Mapping

by Mustafa Tanrıverdi and Tülay Erbesler Ayaşlıgil

Limnol. Rev. 2026, 26(1), 6; https://doi.org/10.3390/limnolrev26010006 - 18 Feb 2026

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Abstract

Floods are natural disasters that cause significant socioeconomic and environmental losses in both urban and rural areas. Within the framework of spatial planning, precautionary measures against flood hazards can be developed using analytical approaches based on different modeling techniques. In this study, flood-prone [...] Read more.

Floods are natural disasters that cause significant socioeconomic and environmental losses in both urban and rural areas. Within the framework of spatial planning, precautionary measures against flood hazards can be developed using analytical approaches based on different modeling techniques. In this study, flood-prone areas in the Melen Basin, Türkiye, were identified and mapped using five statistical methods, namely Frequency Ratio (FR), Shannon Entropy (SE), Evidential Belief Function (EBF), and the hybrid models EBF–SE and EBF–FR. The analysis was conducted using a flood inventory and environmental datasets covering the period 2019–2024, including elevation, slope, aspect, land use, plan and profile curvature, drainage density, distance to river, curve number, long-term average precipitation, geological formation, soil depth, topographic wetness index, sediment transport, and stream power index. Model performances were evaluated using the Receiver Operating Characteristic (ROC) curve and the Area Under the Curve (AUC). The results indicate that the SE method achieved the highest predictive performance (AUC = 0.979), followed by FR (0.974), EBF–SE (0.972), EBF–FR (0.968), and EBF (0.966). According to the FR and SE models, elevation, lithology, and slope were identified as the most influential factors in flood occurrence. In the evaluation of the success index of the models, the following values were determined according to their size: EBF–SE (96.0), SE (94.4), EBF (91.8), FR (81.9), and EBF–FR (79.4). In the classification of flood sensitivity maps, Natural Breaks (Jenks) is the most successful method according to the success index. The findings demonstrate that data-driven and hybrid models can effectively support flood risk assessment and provide valuable input for land-use planning and flood risk management. Full article

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7 pages, 1130 KB

Open AccessPerspective

From Lakes in Poland to Global Water Security: A 25-Year Perspective from the Polish Limnological Society

by Włodzimierz Marszelewski, Piotr Rzymski and Piotr Klimaszyk

Limnol. Rev. 2026, 26(1), 5; https://doi.org/10.3390/limnolrev26010005 - 17 Feb 2026

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Abstract

The designation of 2026 as the World Economic Forum’s Year of Water underscores the growing recognition of freshwater systems as critical to climate resilience, biodiversity conservation, and socio-economic stability. Coinciding with this global initiative, the Polish Limnological Society (PLS) marks its 25th anniversary, [...] Read more.

The designation of 2026 as the World Economic Forum’s Year of Water underscores the growing recognition of freshwater systems as critical to climate resilience, biodiversity conservation, and socio-economic stability. Coinciding with this global initiative, the Polish Limnological Society (PLS) marks its 25th anniversary, offering an opportunity to reflect on the evolving role of limnology in addressing contemporary environmental challenges. Founded in 2001, PLS has advanced integrative research on inland waters, fostered international scientific cooperation, supported scholarly publishing, and promoted societal engagement with freshwater issues. This Perspective highlights society’s contributions to understanding the natural and anthropogenic transformations of lakes and reservoirs, its commitment to open science and education, and its engagement in climate advocacy to address global water security. We argue that the experience of PLS illustrates how sustained, community-driven limnological science can inform policy, management, and public discourse, reinforcing the imperative to safeguard inland waters in an era of accelerating global change. Full article

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9 pages, 866 KB

Open AccessArticle

Hematological Values of Two Species of Amazonian Caimans, Caiman crocodilus and Melanosuchus niger

by Adriano Teixeira de Oliveira, Marcio Quara de Carvalho Santos, Jefferson Raphael Gonzaga de Lemos, Ariany Rabello da Silva Liebl, Maria Fernanda da Silva Gomes, Maiko Willas Soares Ribeiro, Rayana Melo Paixão, Suelen Miranda dos Santos, Adriene Nuzia de Almeida Carvalho, Cristiane Cunha Guimarães, João Paulo Ferreira Rufino, Lucas Maia Garcês, Caterina Faggio and Paulo Henrique Rocha Aride

Limnol. Rev. 2026, 26(1), 4; https://doi.org/10.3390/limnolrev26010004 - 6 Feb 2026

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Abstract

Determining hematological values is essential to provide baseline health and condition data. We evaluated the hematological parameters of free-living individuals of Caiman crocodilus and Melanosuchus niger from the middle Negro River region of Brazil. We captured 18 C. crocodilus and 16 M. niger [...] Read more.

Determining hematological values is essential to provide baseline health and condition data. We evaluated the hematological parameters of free-living individuals of Caiman crocodilus and Melanosuchus niger from the middle Negro River region of Brazil. We captured 18 C. crocodilus and 16 M. niger. Blood was drawn using syringes containing 10% EDTA, and blood parameters were determined as previously described. The analyzed erythrocyte parameters were similar across the species, demonstrating that, despite their different sizes, they share similar strategies for oxygen absorption and transport in the blood. In the morphological analysis of blood cells, erythrocytes, erythroblasts, thrombocytes, lymphocytes, neutrophils, azurophils, heterophils, and basophils were found, and, in the quantification of leukocytes and thrombocytes, it was noted that lymphocytes are the central cells in the blood of the Amazonian caiman. In the plasma metabolite results, no significant differences were observed between glucose and total protein levels. Key physiological parameters were established to assess the health of C. crocodilus and M. niger, enabling the application of this information to sustainable captive production programs and helping to reduce pressure on wild populations. Full article

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9 pages, 2410 KB

Open AccessArticle

First Record of the Invasive Species Melanoides tuberculata (Müller, 1774) (Gastropoda: Thiaridae) in a Tourist Waterfall Complex in the State of Maranhão, Brazil

by Guilherme Silva Miranda, João Gustavo Mendes Rodrigues, Thamirys Borges Galdino, Marcia Regina da Silva Costa, Rafael Costa Leite and Thiago Ferreira Soares

Limnol. Rev. 2026, 26(1), 3; https://doi.org/10.3390/limnolrev26010003 - 6 Feb 2026

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Abstract

Melanoides tuberculata is one of the world’s main invasive snail species; therefore, mapping its occurrence is essential for predicting its dispersion patterns and proposing control measures. This study aimed to map the occurrence of M. tuberculata and its associated parasites in a tourist [...] Read more.

Melanoides tuberculata is one of the world’s main invasive snail species; therefore, mapping its occurrence is essential for predicting its dispersion patterns and proposing control measures. This study aimed to map the occurrence of M. tuberculata and its associated parasites in a tourist waterfall complex located in Fortaleza dos Nogueiras, Southern Maranhão, Brazil. We collected snails over three months (July, August, and September 2025) in the Castanhão, Esmeralda, and Recanto das Águias waterfalls, and in the Panela stream, to estimate their reproductive stage and to assess the presence of parasites. We demonstrated for the first time the occurrence of M. tuberculata at all evaluated collection points. Morphological data of the shells suggested that the M. tuberculata populations were in the initial phase of their reproductive cycle; however, some specimens showed a complete reproductive stage. Additionally, we found M. tuberculata infected with trematode larvae that resembled the Gymnocephalus-type cercariae in the Castanhão waterfall and Panela stream. Therefore, we updated the distribution of M. tuberculata in Brazil and discussed the possible environmental and public health impacts of this species in the study area. Full article

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18 pages, 3379 KB

Open AccessArticle

Fish Communities and Management Challenges in Three Ageing Tropical Reservoirs in Southwestern Nigeria

by Olumide Temitope Julius, Francesco Zangaro, Roberto Massaro, Marco Rainò, Francesca Marcucci, Armando Cazzetta, Franca Sangiorgio, John Bunmi Olasunkanmi, Valeria Specchia, Oluwafemi Ojo Julius, Mahallelah Shauer, Alberto Basset and Maurizio Pinna

Limnol. Rev. 2026, 26(1), 2; https://doi.org/10.3390/limnolrev26010002 - 4 Jan 2026

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Abstract

Three ageing reservoirs in Ekiti State, Nigeria (Ureje constructed in 1958, Egbe in 1982, and Ero in 1989), were comparatively assessed to evaluate fish assemblages and their conservation relevance. Despite the absence of formal fisheries governance, all three reservoirs supported temporally stable fish [...] Read more.

Three ageing reservoirs in Ekiti State, Nigeria (Ureje constructed in 1958, Egbe in 1982, and Ero in 1989), were comparatively assessed to evaluate fish assemblages and their conservation relevance. Despite the absence of formal fisheries governance, all three reservoirs supported temporally stable fish communities with low overall diversity. A core assemblage of six species dominated across sites, while species richness increased from seven species in the small urban Ureje reservoir to nine species in the larger and more rural Ero reservoir. Four native species that have become locally scarce in surrounding river systems (Heterotis niloticus, Parachanna obscura, Hepsetus odoe, and Hyperopisus bebe) persisted at low but consistent abundance. Aquatic environmental variables remained within suitable limits for freshwater fishes, and trophic structure appeared intact across the reservoirs. Catch density was substantially higher in the urban reservoir compared to the rural systems, reflecting spatial differences in fishing intensity. Overall, the findings demonstrate that small tropical reservoirs can function as important freshwater habitats that sustain fish biodiversity and fisheries production in modified landscapes. Full article

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12 pages, 3402 KB

Open AccessArticle

Assessment of Changes in the Size Structure of Ichthyofauna Based on Hydroacoustic Studies, and the Possibility of Assessing Changes in the Ecological State of Lakes on the Example of Lake Dejguny

by Andrzej Hutorowicz

Limnol. Rev. 2026, 26(1), 1; https://doi.org/10.3390/limnolrev26010001 - 30 Dec 2025

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Abstract

The ecological status of lakes based on ichthyofauna, as defined by the Water Framework Directive, is assessed using intercalibrated methods. However, the methods adopted (in Poland, the Lake Fish Index LFI-EN method, based on results of one-off fishing with multi-mesh gillnets) are labor-intensive [...] Read more.

The ecological status of lakes based on ichthyofauna, as defined by the Water Framework Directive, is assessed using intercalibrated methods. However, the methods adopted (in Poland, the Lake Fish Index LFI-EN method, based on results of one-off fishing with multi-mesh gillnets) are labor-intensive and do not allow for frequent repeat testing. Therefore, the concept of a simple model describing changes in the relative number of single traces in the vertical profile (according to the TS target strength distribution) in a lake is presented, as well as an index (the sum of deviations from such a model), enabling quantification of the similarity of TS distributions in lakes with this model. Preliminary analyses were conducted on acoustic data collected in Lake Dejguny. This lake—the condition of which could be estimated based on historical data using the relationships between LFI and the degree of lake eutrophication (expressed by Carlson’s TSI)—was assessed as having a good status in 2006, whereas in 2021, (based on LFI-EN) it had a moderate status. The study tested the TS distribution model, calculated as the arithmetic mean of the relative number of single traces in 2 m-thick layers. It was also shown that the proposed indicator can effectively signal deterioration of ecological status—the sum of the absolute values of the TS distribution deviations in 2021 (moderate status) from the model was more than seven times greater than the sum of the deviations of the distributions from which the model was built (good status). The obtained results confirmed the hypothesis about the possibility of determining a characteristic distribution of single traces in the vertical profile when the lake was classified as being in good condition. Full article

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Limnol. Rev., Volume 26, Issue 1 (March 2026) – 11 articles

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