Freshwater Mussels Research Articles

THE BIOCHEMICAL RESPONSES OF BIVALVE MOLLUSCS TO NEUROLEPTIC CHLORPROMAZINE ARE COMPARABLE WITH THE RESPONSES OF HIGHER VERTEBRATES

Pharmaceuticals such as chlorpromazine (Cpz) are emerging aquatic pollutants with potential effects on non-target organisms. However, its effects on aquatic organisms remain limited and inconclusive. The aim of this study was to compare the responses to Cpz in marine and freshwater bivalve molluscs. Methods. Mytilus galloprovincialis and Unio tumidus were exposed to pM and nM concentrations of Cpz for 14 days and analysed 16 parameters, including cytotoxicity, oxidative/reductive stress responses, metallothionein concentration and biotransformation enzymes in the digestive gland. Results. In both species, Cpz increased EROD activity, possibly leading to the formation of reactive metabolites. Marine mussels exposed to Cpz I and II showed increased GST activity, suggesting detoxification, whereas freshwater mussels showed decreased GST activity, suggesting higher Cpz toxicity. Activation of the GTPase dynamin in U. tumidus exposed to Cpz I confirmed the effect of Cpz on endocytosis. Oxidative stress responses were observed in both species, with changes in oxidative/reductive stress responses, suggesting toxic effects of Cpz. GSH and metallothionein concentrations increased in all exposures, while the NADH/NAD+ ratio increased significantly in U. tumidus. Loss of lysosomal membrane stability was observed in all exposed groups, with CtD efflux detected only in mussels. Differences in caspase-3 activity were also observed between species. Conclusion. Cpz showed adverse effects on vertebrates at μM concentrations, while mussels were affected at pM to nM concentrations, indicating concentration-dependent interspecies effects. Stress responses were similar between species, suggesting that marine molluscs are a potential model for assessing the adverse effects of Cpz on higher vertebrates.

Comparison of three unionid mussel species in removing green microalgae grown in recirculating aquaculture system effluent

Global increase in aquaculture production has created a need to reduce its environmental impacts. Nutrients could be recycled especially at land-based recirculating aquaculture systems (RAS) by cultivating green microalgae in aquaculture effluent. However, microalgae are difficult to harvest. As a multi-trophic solution, mussels could be used in harvesting microalgae. We tested three European freshwater mussels (duck mussel Anodonta anatina, swan mussel A. cygnea, and swollen river mussel Unio tumidus) for filtering two common green microalgae (Monoraphidium griffithii and Selenastrum sp.) grown in RAS effluent. Mussels decreased microalgal concentrations in the tanks 42–83% over three consecutive trials. Algal concentrations at the end of each trial were lowest for both microalgae in tanks containing Anodonta mussels. Clearance rates were higher for Anodonta mussels than for U. tumidus. Mussels biodeposited more microalgae to tank bottoms when M. griffithii was filtered. Ammonium concentration decreased or did not change in tanks with M. griffithii, but increased in tanks containing Selenastrum sp. These results suggest that of the tested species Anodonta mussels and M. griffithii show best potential for RAS effluent bioremediation application. We conclude that a co-culture of microalgae and unionid mussels could be used for recycling nutrients in aquaculture.

Exploring the optimal integrated multi-trophic aquaculture (IMTA) patterns benefiting culture animals and natural water environment

Despite bringing various benefits, rapid developments in aquaculture have contributed to the eutrophication of natural water environments. Therefore, it is imperative to mitigate nutrient load in natural water bodies while ensuring sustainable development of aquaculture. On the basis, we proposed an integrated multi-trophic aquaculture (IMTA) system, which considered a perfect solution and constructed an optimised IMTA pattern. Silver and bighead carps and freshwater pearl mussels were used as purification organisms. Six experimental groups were established for a land-based enclosure experiment: giant freshwater prawn monoculture group (G); giant freshwater prawn and freshwater pearl mussel polyculture group (GH2); giant freshwater prawn and silver and bighead carp polyculture group (GSB); giant freshwater prawn, freshwater pearl mussel and silver and bighead carp polyculture groups (GSBH1, GSBH2 and GSBH3) in different densities of freshwater pearl mussels. Each group had four replicates. Control of cyanobacterial blooms, productivity index, outputs of total nitrogen and total phosphorus and microbial community composition were studied and compared in different culturing patterns. Results showed that the GSBH1 group had the most obvious comprehensive advantages in the above four aspects (no cyanobacterial bloom occurred; the best comprehensive productivity index of giant freshwater prawn; the abundance of beneficial microorganisms in sediments was the highest; reduced phosphorus emissions in tailwater by 60.34%; the utilisation rates of nitrogen and phosphorus increased by 10.99% and 13.05%, respectively). Even so, however, the GSBH1 group might not be the most optimal IMTA pattern in practice because the mortality rate of the mussels reached 12.33% and the weight gain was −3.66%. Additionally, the presence of freshwater pearl mussel at its lowest density in this experiment had exhibited detrimental impacts on the growth of silver and bighead carps. Therefore, the most optimal IMTA pattern needs to be determined by further research.

Potential for juvenile freshwater mussels to settle onto riverbeds from field investigation

Freshwater mussel populations have been declining at an alarming rate around the world. Herein, we investigate whether changing flow conditions, as they affect juvenile freshwater mussel settling, could be a potential causative factor for this decline in the Dan River, North Carolina, USA. We deployed two uplooking velocity sensors on the riverbed between May and November 2019: one where mussels reside and another where they do not. From this data, we calculated shear velocity, which is a measure of the turbulence that acts to lift particles into suspension and acts against particle settling. We determined that a shear velocity less than 0.66 cm/s would be required to settle relatively large and dense juvenile mussels onto the riverbed; however, the lowest shear velocity we measured was 0.9 cm/s. Additionally, we estimated that juvenile freshwater mussels as large as 280-510 µm could always be suspended and not be able to settle onto the riverbed at these two locations. Therefore, the flow during May-November 2019 was high enough to prohibit recruitment of juvenile freshwater mussels at the sensor locations. Furthermore, we have identified that the magnitude of the lowest flows has increased since 2000, which may be exacerbating the decline in freshwater mussels.

An Initial Survey of Unionid Mussels in Lakes East of the Missouri River in South Dakota, USA

This study surveyed freshwater mussels (family Unionidae) in 116 lakes and reservoirs east of the Missouri River in South Dakota, USA, during 2017. Using two-person–hour/site timed searches, evidence of a total of 1789 mussels, including 1053 live mussels, was obtained from 50 waters. Nine species, from two different orders, were found in lakes and reservoirs throughout five of the six major river drainages east of the Missouri River. The native species observed included Giant Floater Pyganodon grandis, Fatmucket Lampsilis siliquoidea, Threeridge Amblema plicata, White Heelsplitter Lasmigona complanata, Wabash Pigtoe Fusconaia flava, Deertoe Truncilla truncata, and Pink Heelsplitter Potamilus alatus. Giant Floater was the most widespread and abundant species observed, representing 63.3% of the live mussels sampled. Two non-native species, Zebra Mussel Dreissena polymorpha and Chinese Basket Clam Corbicula fluminea, were also documented from three water bodies in the lower Missouri River drainage. Overall, mussel abundance was negatively correlated with lake water conductivity and positively correlated with turbidity. No significant correlations were observed between species abundance and water temperature, pH, dissolved oxygen, or substrate particle size.

An investigation into the wound-healing mechanism in gill injuries of varying severity in the freshwater mussel Solenaia oleivora (Heude, 1877)

The Solenaia oleivora is an important freshwater economically farmed shellfish, and the traditional hooking method often causes different degrees of gill damage to the S. oleivora. Therefore, in this study, we investigated the mechanism of wound-healing in gill injuries in the freshwater mussel S. oleivora by simulating varying degrees of gill injury. It was found that the rates of oxygen consumption, ammonia excretion, and feeding did not change significantly in the mild-injury group at 2 and 12 h post-injury, while the rates were significantly lower in the severe-injury group compared with the control group, likely due to impairment of the respiratory metabolism. The rates of oxygen consumption, feeding, and ammonia excretion increased significantly in the mild-injury group at 24, 48, 72 h, compared with the control, as well as in the severe-injury group at 72 h post-injury, possibly due to increased energy requirements for tissue repair. Histological and transcriptomic analyses of tissues showed that in the mild-injury group at 2 and 12 h, blood cells migrated toward the wound, plugging it and triggering an inflammatory response associated with upregulation of TNF signaling, immune-related genes, and genes associated with the actin cytoskeleton, suggesting wound contraction and phagocytosis of blood cells. At 24 h post-injury, genes and pathways associated with antioxidant enzymes, chaperonins, autophagy, lysosomes, biochemical pathways, and energy metabolism were activated, suggesting a transition from an inflammatory response to an epithelialization process. At 48 h post-injury, Toll and Imd signaling were downregulated, together with upregulation of genes associated with the extracellular matrix, such as collagen, integrins, and glycoproteins, promoting epithelialization of the wound. After 72 h, proline and arginine metabolism were increased, as well as expression of mitochondrial genes. The severe-injury group showed reduced amino acid metabolism and activation of primary immunodeficiencies after 2 and 12 h, suggesting disturbances in metabolism and immunity, while after 2, 12, 24, and 48 h, genes related to the actin cytoskeleton, lipid metabolism, glycolysis, glycosyltransferases, chaperonins, guanylate-binding proteins, and NOD-like receptors were upregulated to promote wound contraction and inflammatory responses. At 72 h after injury, interleukin-4 and thymosin β-4 were activated and the NF-κB signaling pathway was inhibited to reduce inflammation, while epithelialization of the wounds was visible on tissue sections, possibly facilitated by the upregulation of ribosomal proteins, ATP. This study provides new insights into the mechanism of gill wound-healing in S oleivora.

Acute Toxicity of the Lampricide 4-Nitro-3-(trifluoromethyl)phenol to the Mussel (Obovaria subrotunda), Its Host (Percina maculata), and a Surrogate Mussel Species (Obovaria olivaria).

The risk of lampricide applications (such as 4-nitro-3-[trifluoromethyl]phenol [TFM]) to nontarget fauna continues to be a concern within the Great Lakes Fishery Commission Sea Lamprey Control Program, especially among imperiled aquatic species-such as native freshwater mussels. The Grand River (Ohio, USA) is routinely treated for larval sea lampreys (Petromyzon marinus), and this river contains populations of the federally threatened mussel Obovaria subrotunda. Given this spatial overlap, information on the sensitivity of O. subrotunda to TFM is needed. Our objectives were to assess the toxicity of TFM to (1) adult Obovaria olivaria (a surrogate for O. subrotunda), (2) glochidial larvae of O. olivaria and O. subrotunda, (3) juveniles of O. olivaria and O. subrotunda, and (4) adult Percina maculata (host for O. subrotunda glochidia). In acute toxicity tests, TFM was not toxic to glochidia and adult mussels at exposure concentrations that exceed typical treatment rates. Although significant dose-response relationships were observed in hosts and juveniles, survival was ≥95% (Percina maculata), ≥93% (O. olivaria), and ≥74% (O. subrotunda) at typical treatment rates. However, the steep slope of these dose-response relationships indicates that an approximately 20% difference in the treatment level can result in nearly an order of magnitude difference in survival. Collectively, these data indicate that routine sea lamprey control operations are unlikely to acutely affect these species or their host. However, given that many mussel species are long-lived (30-100 years), the risks posed by lampricide treatments in the Great Lakes would be further informed by research on the potential long-term effects of lampricides on imperiled species. Environ Toxicol Chem 2024;43:1423-1430. Published 2024. This article is a U.S. Government work and is in the public domain in the USA.

Habitat engineering effects of freshwater mussels in rivers vary across spatial scales

Habitat engineering effects of freshwater mussels in rivers vary across spatial scales

The transcriptome assembly of the European freshwater mussel Unio elongatulus C. Pfeiffer, 1825

Freshwater mussels of the order Unionida are a global conservation concern. Species of this group are strictly freshwater, sessile, slow-growing animals and, extremely sensitive to environmental changes. Human-mediated changes in freshwater habitats are imposing enormous pressure on the survival of freshwater mussels. Although a few flagship species are protected in Europe, other highly imperilled species receive much less attention. Moreover, knowledge about biology, ecology, and evolution and proper conservation assessments of many European species are still sparse. This knowledge gap is further aggravated by the lack of genomic resources available, which are key tools for conservation. Here we present the transcriptome assembly of Unio elongatulus C. Pfeiffer, 1825, one of the least studied European freshwater mussels. Using the individual sequencing outputs from eight physiologically representative mussel tissues, we provide an annotated panel of tissue-specific Relative Gene Expression profiles. These resources are pivotal to studying the species’ biological and ecological features, as well as helping to understand its vulnerability to current and future threats.

Food, water quality, and the growth of a freshwater mussel: Implications for population restoration

Food, water quality, and the growth of a freshwater mussel: Implications for population restoration

Radioactivity from oil and gas produced water accumulated in freshwater mussels

Legacy disposal of oil and gas produced water (OGPW) to surface water has led to radium contamination in streambed sediment creating a long-term radium source. Increased radium activities pose a potential health hazard to benthic organisms, such as freshwater mussels, as radium is capable of bioaccumulation. This project quantifies the impact of OGPW disposal on adult freshwater mussels, Eurynia dilatata, which were examined along the Allegheny River adjacent to a centralized waste treatment facility (CWT) that historically treated and then discharged OGPW. Radium isotopes (226Ra and 228Ra) were measured in streambed sediment, mussel soft tissue, and mussel hard shell collected upstream, at the outfall, 0.5 km downstream, and 5 km downstream of the CWT. Total radium activity was significantly higher (p < 0.05) in mussel tissue (mean = 3.44 ± 0.95 pCi/g), sediment (mean = 1.45 ± 0.19 pCi/g), and hard shell (mean = 0.34 ± 0.11 pCi/g) samples 0.5 km downstream than background samples collected upstream (mean = 1.27 ± 0.24; 0.91 ± 0.09; 0.10 ± 0.02 pCi/g respectively). Mussel shells displayed increased 226Ra activities up to 5 km downstream of the original discharge. Downstream soft tissue and hard shell 87Sr/86Sr ratios, as well as hard shell metal/calcium (e.g., Na/Ca; K/Ca; Mg/Ca) and 228Ra/226Ra ratios demonstrated trends towards values characteristic of Marcellus OGPW. Combined, this study demonstrates multiple lines of evidence for radium retention and bioaccumulation in freshwater mussels resulting from exposure to Marcellus OGPW.

Foundation species stabilize an alternative eutrophic state in nutrient-disturbed ponds via selection on microbial community.

Eutrophication due to nutrient addition can result in major alterations in aquatic ecosystem productivity. Foundation species, individually and interactively, whether present as invasive species or as instruments of ecosystem management and restoration, can have unwanted effects like stabilizing turbid eutrophic states. In this study, we used whole-pond experimental manipulations to investigate the impacts of disturbance by nutrient additions in the presence and absence of two foundation species: Dreissena polymorpha (a freshwater mussel) and Myriophyllum spicatum (a macrophyte). We tracked how nutrient additions to ponds changed the prokaryotic and eukaryotic communities, using 16S, 18S, and COI amplicon sequencing. The nutrient disturbance and foundation species imposed strong selection on the prokaryotic communities, but not on the microbial eukaryotic communities. The prokaryotic communities changed increasingly over time as the nutrient disturbance intensified. Post-disturbance, the foundation species stabilized the prokaryotic communities as observed by the reduced rate of change in community composition. Our analysis suggests that prokaryotic community change contributed both directly and indirectly to major changes in ecosystem properties, including pH and dissolved oxygen. Our work shows that nutrient disturbance and foundation species strongly affect the prokaryotic community composition and stability, and that the presence of foundation species can, in some cases, promote the emergence and persistence of a turbid eutrophic ecosystem state.

Transcriptome analysis of mantle and pearl sac of freshwater pearl mussel Lamellidens marginalis to identify biomineralisation-associated genes

ABSTRACT The freshwater pearl mussel, Lamellidens marginalis, is widely distributed in India and is cultured for freshwater pearl production. Understanding the biomineralisation process sheds light on the genes responsible for nacre secretion. However, information on the transcriptome of L. marginalis mantle tissue and pearl sac is lacking. This study generated transcriptome resources for L. marginalis, identifying genes involved in biomineralisation. Illumina paired-end sequencing yielded 11.13 million raw reads, assembled into 133,246 contigs and 26,373 unigenes. Of these, 21,033 unigenes exhibited homology with previously reported molluscan proteins. Genes related to biomineralisation, such as pif, perlucin, calreticulin, calmodulin, chitin synthase, chitin dehydrogenase, carbonic anhydrase, tyrosinase, shell matrix protein, dermatopontin isoform X1, chitinase 3, chitinase domain-containing protein 1, and putative chitinase-1were identified. This baseline information will help to compare the expression levels between the phenotypes of high-quality and low-quality pearls. Further investigations, incorporating large sample sizes and phenotype information, could assist in identifying type I genetic markers linked to pearl quality.

Clumped isotopes reveal relationship between mussel growth and river discharge

Freshwater mussels preserve valuable information about hydrology, climate, and population dynamics, but developing seasonal chronologies can be problematic. Using clumped isotope thermometry, we produced high-resolution reconstructions of modern and historic (~ 1900) temperatures and δ18Owater from mussel shells collected from an impounded river, the Brazos in Texas, before and after damming. We also performed high-resolution growth band analyses to investigate relationships between mussel growth rate, rainfall, and seasonal temperature. Reconstructed δ18Owater and temperature vary little between the modern (3R5) and historic shell (H3R). However, a positive relationship between reconstructed δ18Owater and growth rate in H3R indicates that aside from diminished growth in winter, precipitation and flow rate are the strongest controls on mussel growth in both modern and pre-dam times. Overall, our results demonstrate (1) the impact, both positive and negative, of environmental factors such as flow alteration and temperature on mussel growth and (2) the potential for clumped isotopes in freshwater mussels as a paleohydrology and paleoclimate proxies in terrestrial environments.

Morphometry and length-weight relationships of the freshwater pearl mussel Parreysia corrugata (Muller 1774) (Bivalvia: Unionidae) from Daya River, Odisha, India

Allometry in the freshwater mussel Parreysia corrugata was studied from east-flowing riverDaya, Bhubaneswar, India. The results indicated that shell length (SL)-shell height (SH) andshell length-shell width (SW) relationships for P. corrugata were SH = 0.876 + 0.932SL andSW = 0.625 + 0.898SL. Greater correlation was found between SL and SW than between SLand SH. The length-weight, height-weight and width-weight relationships of P. corrugata wereestablished as TW = 0.00038SL2.80, TW = 0.0006SH2.95 and TW = 0.0023SW2.97 respectively.The t-test value of b indicated an isometric growth pattern in the width-weight and theheight-weight relationships. The highest r2 value was obtained for shell length-total weightand shell height-total weight equations. Present study will be helpful in strengthening theknowledge on interrelationship between the morphometric variables of P. corrugata and alsoin comparing with the earlier studies to know the existence of spatial or temporal variabilityin the morphometry of this species. This information can also be used to better understandthe biology of P. corrugata and to improve the management of this species. Keywords:Conservation, Daya River, Length-weight relationships,Morphometry

Conservation Challenges Imposed by Evolutionary History and Habitat Suitability Shifts of Endangered Freshwater Mussels under a Global Climate Change Scenario

Climate change and associated shifts in temperature and precipitation patterns have become an increasing concern as drivers of ongoing biodiversity loss. The Mediterranean region is particularly vulnerable, being both a biodiversity hotspot and a region very prone to desertification. Freshwater mussels are amongst the most threatened invertebrate taxa worldwide. Unio tumidiformis is an endemic and endangered species restricted to the southern Iberian Peninsula, living in temporary Mediterranean-type streams. Freshwater mussels need a fish host for successful larval transformation, meaning U. tumidiformis must belong to the genus Squalius. The main objective of this study was to evaluate the vulnerability of U. tumidiformis to climate change, by studying its population genetics and evolutionary history, its current and future habitat suitability, and that of its hosts. Genetic population structure and diversity were assessed using Single-Nucleotide Polymorphisms through Genotyping by Sequencing and used to infer species evolutionary history. The species potential distribution was modeled using an ensemble forecasting approach, and future shifts in habitat suitability were assessed with the projected climate data layers from Worldclim. Most populations showed extreme genetic differentiation (Fst up to 0.745), even from close neighboring ones. Upper Guadiana populations were more diverse and less differentiated. We hypothesize that U. tumidiformis originated in Upper Guadiana and followed the same colonization routes as their hosts with numerous founder effects and bottlenecks. Our results also predicted a reduction of 99% of climatically suitable areas for U. tumidiformis in the Iberian Peninsula until 2040. For the fish hosts, a maximum 42% reduction in suitable areas was estimated throughout the century, with remaining adequate habitats in the north. Our results suggest that difficult conservation options are necessary, prioritizing the preservation of populations, translocations to the northern area of its historical range and stream engineering to increase resilience to droughts.

Behavioral and Biochemical Variations in Unio tigridis After Exposure to Lead Nitrate

This study was carried out with the freshwater mussel Unio tigridis exposed to lead nitrate. The samples of water and mussels were collected from Qandil water resources situated in Qandil village at 36° 37' 39.55" north latitude and 44° 10' 51.80" east longitude, and it is 322 meters above sea level. In January 2022, rivers and aquariums water were tested for temperature, pH, EC, TDS, DO, total alkalinity, total hardness, and calcium and magnesium ions. Studied organisms were exposed to variable concentrations of lead nitrate ranging from 0 to 900 ppm. The 96-h median lethal concentration (LC50) was measured and a comparison was made between the behavioural responses of the control and treatment groups. Also, the concentrations of lead in the experimental media, shell, and soft tissue of mussels were measured. A sample of mussels collected from aquarium was tested for biochemical markers, including acetylcholinesterase (AChE), Glutathione S-Transferase (GST), Catalase (CAT) and malondialdehyde (MDA). After 96 hours, the LC50 was estimated to be 782.7 ppm. The findings on behaviours revealed that lead slows down species' activities. Lead concentratiom increased within the mussel body as the water lead level decreased. The value of AChE was inversely related to lead concentration. However, GST, CAT and MDA increased with lead exposure.

Which environmental factors influence the distribution patterns of an endangered freshwater mussel (Unio crassus)?

Freshwater mussels (Bivalvia: Unionida) are valuable components of river ecosystems. Among them, the thick-shelled river mussel (Unio crassus) is globally endangered, and its populations are decreasing in many European catchments. Over the last decade, it has become a focal point of environmental conservation programs. A comprehensive understanding of the relationship between the species and its environment is therefore required to optimize those programs. Yet, despite being increasingly studied, freshwater mussel ecological requirements remain complex to establish as they appear to be species- and region-related. We reviewed the potential environmental factors which have been showed to impact freshwater mussels, and therefore possibly U. crassus. We compiled datasets of environmental factors and occurrence of U. crassus across the study area (Wallonia, Belgium). Logistic regression models were built to identify the main driving factors. Results underscore the predominant significance of hydro-geomorphological variables in shaping distribution patterns. Specific stream power had a significantly negative impact on the distribution of U. crassus, while the probability of occurrence increased with catchment area, and with contrasted high- and low flows during the year. The high prediction accuracy of the hydro-geomorphological model supports the idea of a considerable influence of hydro-geomorphological habitat on the species. Other parameters are also relevant in predicting mussel distribution, like the percentage of land covered by meadows, elevated heavy metals concentrations and fish richness.

Acute and Chonic Effects of Silver Nanoparticles (AgNPs) on Unio delicatus

The widespread use of silver nanoparticles (AgNPs) including water filters, paints, cosmetics, deodorants, clothing, textiles, food packaging, electrical appliances and medical devices inevitably leads to their release into the natural environment, bioaccumulation in organisms and persistent accumulation in natural aquatic systems. The aim of this study is to investigate the acute and chronic effects of silver nanoparticles, which can contaminate aquatic ecosystems, in freshwater mussels, one of the aquatic invertebrate organisms. The model organism of the study, Unio delicatus, was obtained from Gölbaşı Lake (Hatay). After that acclimation was performed in the laboratory for two weeks. The mussels were then exposed to 1 and 10 mg/L AgNPs for 7 and 21 days. At the end of the exposure period, hemolymph and tissue samples of the mussels were taken. Total hemocyte count from hemolymph samples, lipid peroxidation and glutathione levels from tissue samples (digestive gland and gill) were investigated. Acute exposure resulted in an increase in the total hemocyte counts, while chronic exposure resulted in a significant decrease (P

Diversity of Freshwater Mollusks from Lake Pampulha, Municipality of Belo Horizonte, Minas Gerais, Brazil

The artificially created Lake Pampulha, within the metropolitan area of Belo Horizonte, Minas Gerais State, lacks detailed information about its freshwater mollusks, representing a challenge for the assessment and conservation of this ecosystem. In this study, conducted during June and August 2021, we collected specimens on four different occasions and at five sampling points around the lake, using different sampling equipment, such as a shovel and a scoop. During these collections, we identified, enumerated and measured 1538 species of mollusks and additionally examined the presence of trematode larvae. We identified twelve species of fresh water bivalves and gastropods: Biomphalaria straminea, Biomphalaria kuhniana, Biomphalaria occidentalis, Drepanotrema cimex, Pomacea maculata, Stenophysa marmorata, Physa acuta, Gundlachia ticaga, Melanoides tuberculata, Pseudosuccinea columella, Omalonyx matheroni and Corbicula largillierti. Echinostome and strigeocercaria types of larval trematodes were detected in B. straminea. Notably, some species of mollusks have not previously been recorded at Lake Pampulha. The analyses revealed differences in the composition and abundance of species, highlighting the higher number of mollusk species in areas more impacted by human actions. This study expands our understanding of mollusk diversity at Lake Pampulha, and provides valuable data for longitudinal comparisons of water quality and considerations of the conservation of native species. Furthermore, it highlights the importance of choosing appropriate sampling equipment, depending on the research objectives. The presence of invasive species of medical and veterinary relevance as intermediate hosts of parasites reinforces the need for efficient environmental protection strategies to preserve this artificial, aquatic environment widely used by the local population and by tourists.