Aquatic Ecosystem Health & Management

Fish hematology diagnosis as a protocol to evaluate aquatic pollution: Ariopsis felis catfish the Gulf of Mexico, study case.

Misael Hernández Díaz — 2025-12-23

Aquatic pollution is a problem that has increased over time, affecting organisms of biological and commercial importance. Fish are valuable pollution bioindicators, lacking minimal invasive protocols to assess their health. Fish blood is sensitive to environmental stressors and is easy to obtain using minimally invasive and low-cost techniques, making it a powerful tool for monitoring pollution using fish. For this reason, the morphological and cytogenetic changes in erythrocytes serve as pollution indicators in different aquatic bodies, such as coastal areas like the Gulf of Mexico. Accordingly, we generated a protocol to evaluate aquatic contamination through fish hematological diagnosis. Briefly, the protocol consists of the collection of fish and the extraction of their blood. These samples serve to characterize erythrocyte counts and morphology through Giemsa-stained smears. Additionally, comet assays determine the degree of genotoxic damage. Altogether, we generated a hematological status summing the parameters indexes to determine the fish health diagnosis, giving an overall idea of the environmental health status. Particularly, the catfish (Ariopsis felis) from Tecolutla estuarine system presented morphological changes such as poikilocytosis, echinocytosis, hypochromia, variations in nuclear morphology, as well as a moderate-to-high genotoxicity level. These results indicated a moderate and high genotoxic degree and slightly contamination. To sum up, this study endorses the use of minimally invasive protocols, compared to others that require the death of organisms, to assess the health status of aquatic bodies bioindicators. Overall, the protocol developed in this study establishes a health diagnosis based on morphological alterations and genotoxic damage in the erythrocytes of catfish (A. felis) from Tecolutla, Veracruz, Mexico.

Embriotoxicity and neurotoxic effects on Danio rerio produced by the water of a Cutzamala reservoir: Villa Victoria dam

Misael Hernández-Díaz — 2025-12-23

The Cutzamala system is made up of several storage dams, one of them is the Villa Victoria Dam which, over time, has presented problems such as deforestation for agriculture, high demand for water, droughts, decline in aquatic population and water pollution. Due to this, the aim of this work was to evaluate the embryotoxicity and neurotoxic effects in Danio rerio produced by the water of this reservoir. Embryotoxicity was determined through the general morphological score, teratogenic index and % mortality. Oxidative damage was identified by the antioxidant enzymes activity and the degree of carbonylated protein content and lipoperoxidation in the larvae. Neurotoxic effects were assessed through acetylcholinesterase activity and ache and nrxn1 gene expression, in addition to behavioral changes in the larvae through basal locomotor activity, visual motor response, and thigmotaxis. A reduction in embryonic development, teratogenic alterations and a high percentage of embryo mortality were observed. Likewise, changes in the activity of antioxidant enzymes, as well as lipoperoxidation and carbonylated proteins, were identified. Finally, an increase in the enzymatic activity of acetylcholinesterase and overexpression of ache and nrxn1 was observed, which resulted in the reduction of basal locomotor activity, visual motor response and negative thigmotaxis in D. rerio larvae. These results demonstrate the effects of contamination in the Villa Victoria Dam and the risk that this and other problems affect the water quality of the reservoir.

Algal growth potential and water quality of La Culebra stream in the Guadalajara Metropolitan Area (México)

Karen Aidé Carrillo-González — 2025-12-23

Background. La Culebra stream originates in Los Colomos Urban Forest (LCUF) within the Guadalajara Metropolitan Area (GMA), which is preserved almost naturally with few human interventions in the studied section. The stream flows from springs that emerge within the LCUF. There are no records of the water quality of La Culebra stream. It is of great interest to know its characteristics to propose management alternatives.

Methods. Using physicochemical techniques and test organisms, the behavior of macronutrients in the water, the existence of inhibition factors and the presence of coliforms were investigated during six months representative of the seasonality of the year 2018. Results. The stream was found with low concentration of nutrients and with a variability in its physicochemistry and biology depending on the seasonal cycle. The system maintains adequate levels of dissolved oxygen to support the respiration of organisms in the water column, and particularly the upper layer of the sediments. Using test algae, it was revealed the presence of an inhibition factor. Although coliform levels were high in all samples, their presence is not from human origin, but of ducks and small mammals that normally inhabit the urban forest.

Conclusions. Nevertheless, the stream presents ecological functionality, we recommend conducting microbiological studies of groundwater to confirm the natural origin of coliforms. Likewise, it is recommended that studies be implemented to characterize the nature of the inhibiting agent that we have detected. Finally, it is recommended that the administrative authority of the LCUF manage funds for the dissemination and preservation of La Culebra stream as a subject of high environmental and cultural value in the GMA.

Water quality assessment of Villa Victoria and Madin reservoirs: a case study

Alba Lucero García-Medina — 2025-12-23

The presence of contaminants, such as metals, in water storage systems leads to a risk of adverse effects on human health and aquatic organisms since these substances are difficult to eliminate and are often recycled through physicochemical and biological processes. In recent years, there has been severe hydrological stress in the Madin and Villa Victoria reservoirs, in addition to an increase in industrial and agricultural activities around these systems, so the release of contaminants into the water is becoming more frequent. The objective of this research was to determine the environmental risk associated with the contaminants present in the Madin and Villa Victoria reservoirs, as well as the degree of toxicity of the water, allowing us to obtain a deeper understanding of the water quality of these reservoirs over time. For this, the quality index was established using the physicochemical parameters of interest for the development of aquatic organisms reported from 2013 to 2020 based on the methodology of the Canadian Council of the Ministry of the Environment. In Madin Dam, the water quality was poor and marginal depending on the site, while for Villa Victoria, the index is between marginal and acceptable. It was also observed that water toxicity in species such as Danio rerio, Allium cepa, and Vibrio fischeri varies based on the amount of metals found in the water samples; therefore, the presence of contaminants in the water can cause potential adverse effects on the aquatic organisms that inhabit these reservoirs, as a risk quotient greater than one was found in both reservoirs.

Glibenclamide-mediated oxidative stress in zebrafish (Danio rerio) embryogenesis: A comprehensive analysis

Denisse Sarahí Martínez-Urdaibay — 2025-12-23

Given the escalating use of glibenclamide as a commonly prescribed antidiabetic medication, concerns have arisen regarding its potential ecological impact on aquatic organisms. This study presents a comprehensive analysis of the impact of glibenclamide exposure on the embryogenesis of zebrafish (Danio rerio), providing insights into the intricate dynamics of oxidative stress. Leveraging the transparency of zebrafish embryos and their genetic resemblance to humans, the study conducted real-time observations of developmental processes, employing rigorous toxicity assessments to elucidate concentration-dependent patterns in embryo mortality and malformations. The results revealed a substantial increase in embryo mortality rates with elevated glibenclamide concentrations, reaching 76% at the highest tested concentration of 750 µg L^-1, underscoring its detrimental impact. Correspondingly, malformation rates surged at higher glibenclamide concentrations, with 69.4% of embryos exhibiting malformations at 750 µg L^-1. Probit analysis determined a median lethal concentration of 329.3 µg L^-1 and a median effective concentration of malformations of 401.9 µg L^-1, categorizing glibenclamide as an embryolethal substance. Moreover, oxidative stress emerged as a pivotal mechanism, supported by increased lipid peroxidation, and altered antioxidant enzyme activity. The study delved into gene expression, revealing upregulated antioxidant-related genes and delayed expression of apoptosis-related genes. This research significantly enhances our understanding of the broader environmental implications of glibenclamide usage, emphasizing the interconnectedness of human health and the natural world. By highlighting the potential risks associated with glibenclamide exposure during embryonic development, it offers valuable insights into the ecological footprint of other pharmaceutical agents operating through similar mechanisms.

Impact of aluminum on oxidative stress and behavior-related biomarkers in Cyprinus carpio larvae

Karina Ruiz-Lara — 2025-12-23

Exposure to metals like aluminum (Al) is an increasing concern in aquatic environments, affecting both wildlife and human health. This study investigates the effects of Al on 6-day post-fertilization Cyprinus carpio larvae, focusing on oxidative stress biomarkers, neurochemical responses, gene expression, and behavioral alterations. The results showed a significant reduction in SOD, CAT, and GPx activity in larvae exposed to Al, indicating oxidative stress. The findings reveal that Al exposure induces oxidative damage, inhibits acetylcholinesterase activity, reduces dopamine levels, and reduced locomotor activity and visual motor response, along with increased thigmotaxis. In conclusion, Al exposure during critical stages of C. carpio development induces oxidative stress, cellular damage, and neurobehavioral dysfunction. These findings highlight the importance of understanding the ecological impacts of metal pollution in aquatic environments and the need for mitigation strategies to protect the health of aquatic organisms.

Effects of exposure to polyethylene microplastics on embryotoxicity, teratogenesis, and oxidative stress in Xenopus laevis embryos and larvae

Jesus Daniel Cardoso Vera — 2025-12-23

Polyethylene (PE) is a key component of the global plastic polymer demand, accounting for approximately 30% and generating an annual volume of approximately 140 million tons. The presence of PE microplastics (PE-MP) in aquatic ecosystems, including wastewater, rivers, seas, estuaries, groundwater, and drinking water, poses a significant risk to aquatic organisms. The current study evaluated the effect of PE-MP on embryonic development and oxidative stress in Xenopus laevis embryos and larvae. In accordance with the guidelines set forth in the standard protocol for conducting the frog-Xenopus embryo teratogenesis assay (FETAX), embryos were subjected to various environmentally relevant concentrations of PE-MP (3.1, 6.2, 12.5, 25, 50, and 100 mg L^-1) for a period of 96 h. This study evaluated mortality, presence and severity of malformations, growth (larval size), and biomarkers of oxidative stress, including lipid peroxidation, hydroperoxide content, protein carbonyl content, and SOD and CAT enzyme activities. The results demonstrated a concentration-dependent increase in mortality, frequency and severity of malformations, and alterations in oxidative stress biomarkers in X. laevis embryos and larvae exposed to PE-MP. Specifically, exposure to PE-MP led to a significant decrease in larval size and a significant increase in oxidative stress biomarkers, indicating embryotoxic and teratogenic effects. These findings emphasize the need for future research to explore the effects of MPs on embryonic development in other aquatic organisms.

Nonsteroidal anti-inflammatory drugs manufacturing facility effluent induced teratogenesis and oxidative stress in Xenopus laevis

Itzayana Pérez-Alvarez — 2025-12-23

Pharmaceutical manufacturing facilities are mainly concentrated in the center of the country, and the amount of waste generated by manufacturing processes is vast and diverse, including pharmaceutical compounds, organic solvents, detergents, degradation products, heterocyclic compounds, reactive intermediates, and chlorinated products. Unfortunately, many of these facilities lack adequate wastewater treatment plants, allowing residual compounds to reach water bodies and interact with non-target organisms, resulting in adverse effects. This work aimed to evaluate the toxicity of a pharmaceutical effluent. For this purpose, we performed the Frog Embryo Teratogenesis Assay-Xenopus (FETAX) assay and exposed Xenopus laevis embryos to six proportions of a pharmaceutical industry effluent (0.1, 0.2, 0.4, 0.8, 1.5%). The median lethal concentration (LC₅₀), median effective malformation concentration (EC₅₀), minimum growth inhibitory concentration (MCIG), and teratogenic index (TI) were then calculated, and oxidative damage and antioxidant enzyme activity were evaluated. As the teratogenic index value for this effluent was 2.60, it could be considered a hazard, and the minimum growth inhibitory concentration was 0.1 %. Several malformations were observed, the most common being axial malformations (tail, notochord, and fin), cardiac edema, cerebral edema, and microcephaly. Hydroperoxides, lipid peroxidation, and protein carbonylation increased after effluent exposure, as did superoxide dismutase and catalase activities.

Evaluation of metals and their teratogenic effects in Lepidochelys olivacea in Puerto Arista, Chiapas, Mexico

Tania Vázquez Rodríguez — 2025-12-23

Metals in high concentrations cause harmful effects on ecosystems, affecting organisms that have wide-ranging migrations and specific eating habits such as sea turtles. These reptiles have limited metal elimination routes, including excretion through eggs, which contributes to the appearance of malformations in offsprings and embryos. Therefore, the objective of this research was to evaluate the concentrations of Pb, Cr, Cu, and Cd in neonates dead and unborn of the turtle Lepidochelys olivacea, as well as the identification of body regions with a higher malformation index (MI) and its possible relationship with teratogenic effects due to exposure to said contaminants. 24 embryos and 11 hatchlings were collected and analyzed from a turtle camp in Tonala, Chiapas, Mexico. 21 malformations were identified, to which a lethality level was assigned; also, the intensity and incidence rates were calculated. The region with the highest IM was the shell (60.7%). The most frequent malformations were irregular plates (18%) and compressed shell (11.2%). The intensity was 2.5 (m/organism) and 0.2 (m/nest), with an incidence of 1.3. The metals were analyzed by atomic absorption spectrophotometry, and metal concentrations were Pb>Cr>Cu>Cd in both groups. The average concentrations in neonates were 38.5 mg kg ^-1Pb, 8.5 mg kg ^-1Cr, 3.7 mg kg ^-1Cu, and 3.1 mg kg ^-1Cd, while in offspring they were 32.1 mg kg ^-1Pb, 7.2 mg kg ^-1Cr, 4.1 mg kg ^-1Cu and 4.0 mg kg ^-1Cd. No correlation was found between malformations and metals.

Mass loss and nutrient release of sloughed Cladophora

J.A. Wagner — 2025-12-23

Cladophora remains a nuisance algae across the Great Lakes region, and although its growth dynamics and nutrient needs are well-researched, little information is available on decomposition dynamics and nutrient release. We conducted a full-factorial laboratory experiment to investigate how wave action and presence of an omnivorous consumer (crayfish) affected the rate of tissue breakdown and subsequent leaching of nutrients back to the water column. Cladophora tissue lost roughly 70% of its wet weight within 20 days in all treatment tanks. Chlorophyl a content and %C declined over time in the tissues, whereas %N and %P in the tissue increased slightly over the experiment duration. Treatments with turbulence resulted in rapid disintegration of the algae, leaving the remaining material in suspension, whereas tissues in the control treatment remained in a single mass at the bottom of each aquaria. Cladophora tissue was shredded in crayfish tanks, but there was no evidence of consumption. Water column nutrient dynamics were complex, with significant time*treatment interactions making conclusions difficult. Overall, there was a reduction in water column SRP concentrations early in the experiment, followed by an increase across all treatments, suggesting that the algae was still absorbing SRP over the first 10 days, but then leaching this nutrient over the remaining 10 days. Collectively, these findings suggest that sloughed Cladophora was still photosynthetically active initially, but within 10 days leached nutrients back to the water column. Further work is needed to quantify the magnitude of this release and determine its potential for fueling late summer benthic or planktonic primary production.

Tracing the contribution of Latin American research to AEHM: A scientiometric perspective on past trends and future opportunities

Diego Lercari — 2025-12-23

The Aquatic Ecosystem Health and Management (AEHM) journal has served as a well-known platform
for disseminating ecosystem-based research across freshwater and marine systems over the last quarter
century. In this regard, we have made a comprehensive bibliometric and science mapping analysis of
AEHM (1998–2024), with a particular accent on the evolution and patterns of contributions from countries
of Latin America. We believe our perspective may enrich the understanding of the journal’s scholarly
dynamics and offer insight into potential paths to further its mission of fostering global ecosystem health.
Our analysis was based on the SCOPUS database and included 1,346 documents published between
1998 and 2024. The collection encompasses a variety of document types, with a predominance of original
articles (997), complemented by conference papers (171), reviews (49), editorials, and other formats. The
average citation per document was nearly 12, with a modest but consistent citation rate (0.8 per year),
reflecting sustained engagement from the academic community.
The overall authorship profile shows a strong collaborative orientation, with an average of 3.5 coauthors per article and a collaboration index of 2.9 (i.e. how many authors participate on average in
collaborative articles, excluding single-authored papers). This indicates that AEHM functions as a nexus
for interdisciplinary work and collective knowledge production. When focusing on Latin America, 108
documents were identified with at least one author affiliated to a Latin American institution. Although this
represents a modest portion of the total, these contributions demonstrated higher impact, with 21 average
citations per document and a higher collaboration index (3.9), underscoring their relevance and degree of
cooperation.