Freshwater Fish Research Articles

The difference of the composition and digestive enzymes of gut microbiome in herbivorous blunt snout bream (Megalobrama amblycephala) and carnivorous largemouth bass (Micropterus salmoides)

Blunt snout bream (Megalobrama amblycephala) and largemouth bass (Micropterus salmoides) are a herbivorous and a carnivorous freshwater fish species respectively. These fish possess distinct intestinal microorganisms and digestive enzymes that play a vital role in nutrient digestion. As a result, herbivorous and carnivorous fish exhibit significant differences in their digestive strategies. In this study, we investigated the compositions and functions of the gut flora of herbivorous M. amblycephala and carnivorous M. salmoides by 16S rRNA sequencing. PCoA analysis revealed that the gut flora of M. amblycephala and M. salmoides formed two distinct clusters. OTU analysis found that M. amblycephala and M. salmoides shared a small number, but high abundance, of core microorganisms, and that a large number of microorganisms differed at the phylum and genus levels between the two species. The cellulose-degrading bacteria Longivirga, Flavobacterium, Clostridium_sensu_stricto_12, and Bacillus were dominant in M. amblycephala, while protein-degrading bacteria Clostridium_sensu_stricto_1, Lactococcus, Streptococcus and Proteiniclasticum were dominant in M. salmoides. PICRUSt analysis showed significant differences in carbohydrate and protein metabolism functions as well. In addition, cellulase and amylase activities were significantly higher in M. amblycephala than in M. salmoides, while trypsin activity was significantly higher in M. salmoides than in M. amblycephala. These results indicated that dietary patterns influenced the composition and function of the bacterial community and the activity of digestive enzymes in the host’s gut.

Fish responses to underwater sounds depend on auditory adaptations: An experimental test of the effect of motorboat sounds on the fish community of a large fluvial lake.

Freshwater fishes exhibit a wide range of auditory adaptations and capabilities, which are assumed to help them navigate their environment, avoid predators, and find potential mates. Yet, we know very little about how freshwater environments sound to fish, or how fish with different auditory adaptations respond to different soundscapes. We first compiled data on fish hearing acuity and adaptations and provided a portrait of how anthropogenic sounds compare to natural sounds in different freshwater soundscapes. We then conducted a sound-enrichment field experiment at Lake Saint Pierre, a large fluvial lake in Canada, to evaluate the effect of motorboat sound exposure on the fish community by looking at the extent to which changes in species abundances were linked to auditory adaptations. Data compilation showed that the hearing acuity of most species overlaps with a wide range of ambient and anthropogenic underwater sounds while the field experiment showed that species with more specialized auditory structures were captured less often in sound-enriched traps, indicating avoidance behavior. Our findings highlight the importance of considering species' sensorial adaptations when evaluating the community-scale effects of anthropogenic sounds on the fish community, especially at low levels of anthropogenic activity.

Spatial extent drives patterns of relative climate change sensitivity for freshwater fishes of the United States

AbstractAssessing the sensitivity of freshwater species to climate change is an essential component of prioritizing conservation efforts for threatened freshwater ecosystems and organisms. Sensitivity to climate change can be systematically evaluated for multiple species using geographic attributes such as range size and climate niche breadth, and using species traits associated with climate change sensitivity. These systematic evaluations produce relative rankings of species sensitivity to aid conservation prioritization and to identify relatively sensitive species that may otherwise be understudied or overlooked. Due in part to biogeographic constraints, species assemblages change across regions and spatial extents; yet, the degree to which spatial factors influence relative rankings of species sensitivity is unclear. The spatial extent of multispecies analyses may alter relative rankings of species climate sensitivity; alternatively, relative climate sensitivity may be conserved among spatial scales, resulting in consistent identification of sensitive species among regions and spatial extents. We investigated how spatial extent influences our understanding of relative climate sensitivity for 137 native freshwater fishes of the United States that were representative of taxonomic, trait, and geographic diversity. Using publicly available occurrence data from the Global Biodiversity Information Facility, we calculated a systematic, geographically derived index of climate change sensitivity for study species at national and regional extents, including within four major hydrologic subregions of the United States. We examined the effects of spatial extent on the relative ranking of climate sensitivity among species, and we explored relationships among climate sensitivity, species traits, and conservation status at regional and national extents. We found that climate sensitivity rankings of species were influenced by spatial extent in some specific instances, but that relative rankings were largely conserved across spatial scales. However, correlations among geographically derived climate sensitivity rankings and species traits associated with climate sensitivity were variable across scales and regions, suggesting that links between geographic rarity and species traits may be scale‐dependent in some cases. Finally, we found few associations between climate sensitivity and current conservation status among species. Systematic approaches to quantifying climate sensitivity may offer an opportunity to identify sensitive but overlooked species for pre‐listing actions such as monitoring or conservation agreements.

Analysis of fish consumption patterns in the people of Bekasi Regency, West Java

Bekasi people's awareness to consume fish is still very low. Though fish is one of the foods that are cheap, easy to find, and have a high nutritional content. The purpose of this study was to analyze fish consumption patterns. The study was conducted by analyzing primary data on fish consumption patterns influenced by perceptions and preferences for fish products through direct interviews with 110 household members. The methods used in this study are descriptive analysis, logit analysis, quantitative analysis using the Chi-square test. The choice of fish as a source of animal protein consumed shows the consumption pattern of fresh fish both freshwater fish and seawater fish, based on the frequency of consumption patterns included in the large category, namely 70.9% fresh seawater fish and 24.5% fresh freshwater fish.

Status and distribution of a novel redfin lineage, Pseudobarbus sp. ‘burchelli Tradouw’ from the Cape Fold Ecoregion of South Africa

Freshwater fish are threatened globally and in addition, knowledge of their diversity is incomplete and species richness is underestimated. Within the ichthyofauna of the Cape Fold Ecoregion of South Africa, many undescribed lineages exist and for most of these, information is limited regarding their ecology, distribution and threats. The Tradouw redfin Pseudobarbus sp. ‘burchelli Tradouw’ is a novel and range-restricted lineage within the Breede River redfin Pseudobarbus burchelli. Annual monitoring conducted between 2012 and 2016 investigated spatial and temporal trends in the distribution and population dynamics of this taxon. Results indicated that it is highly fragmented within its distribution range, likely a result of the combined pressures of invasive fish and poor land use practices. Short-term monitoring results indicated that invasive fish are established in most of the catchment and that the relative abundance of redfins remained constant only in the limited section of river where alien fish were absent. Poor land use practices such as water over-abstraction and surface water pollution, are pervasive threats, but the extent to which these affect the redfins requires further investigation. The long-term survival of this taxon remains uncertain, and short-term and long-term conservation and management options are explored.

Common processes drive metacommunity structure in freshwater fish

AbstractAimEnvironmental change affects metacommunity structure both directly—via abiotic factors and dispersal that affect species occurrence—and indirectly—via complex interactions among co‐occurring species. We examined how the three main metacommunity factors—environmental conditions, spatial processes and species associations—affect metacommunity structure and whether responses are predictable in real‐world systems by using novel methods to disentangle the drivers.LocationEastern Asia, northern Europe and central North America.Time periodContemporary.Major taxa studiedFreshwater fish.MethodsWe used a dataset of freshwater fish species occurrences in temperate lakes in three countries in different biogeographic regions. We analysed co‐occurrence patterns by using a joint species distribution model.ResultsWe demonstrated that environmental processes are the main drivers of species' distribution and diversity, suggesting that future climate change (anthropogenic alteration of abiotic factors) will heavily influence the structure of metacommunities. We also showed that spatial processes and species interactions mediated the influence of environmental processes, especially at the lake level.Main conclusionsOur results indicate that ongoing changes in metacommunity structure are modulated not only by the direct impacts of shifting abiotic factors but also by indirect effects of species interactions. Our global analysis indicates that even under the current high rate of environmental change, an identifiable set of underlying processes can be used to predict impacts of this change on metacommunity structure.

Rancang Bangun Akuarium Dengan Pengkondisian PH Air Otomatis Berbasis PLTS

Many people in Indonesia keep freshwater ornamental fish, including guppy fish (Poecilia reticulata), green growth fish (Gyrinocheilus aymonieri), neon tetra fish (Paracheirodon innesi). Neon tetra fish are popular because of their distinctive striking and bright body lines, while guppy fish are kept because of their ease of care and beautiful color variations, especially in male guppies. Guppy fish can grow well at temperatures of 22°C - 27°C and pH 6.5-7.2. Because managers are busy, this becomes an obstacle in fish cultivation, because the water quality that determines fish development becomes unstable. The results of the PLTS output test for 7 days 7 hours per day from 09.00 – 15.00 WIB can charge the battery with an average voltage of 13.89 V and an average current of 1.2 A and an average power of 14.15 W and can run for 24 hours. O'clock. Testing the battery for 7 days and 7 hours from 09.00 – 15.00 WIB can meet power needs for 24 hours with an average battery voltage of 13.36 V and an average current of 0.71 A. Meanwhile, the test results for the servo motor with a feed weight of 2, 45 grams and a servo motor delay of 2 seconds. Testing the pH of the water using a pH pump showed a change from the initial value of 8.06 to 6.91 and was measured with the PH4502C sensor. Tests without a PH pump showed an increase in changes from the initial pH value of 7.76 to 8.05.

Bussiness Management System Of Catfish Cultivation Using Fuzzy Inference System Tsukamoto Methods

Catfish is a type of freshwater fish that is in great demand among people because it has high nutritional value. The high demand for catfish on the market is a promising business opportunity. The relatively fast maintenance period makes this cultivation much in demand. Management of a catfish farming business requires good strategy and planning so that the business process can provide optimal profits. Appropriate management practices, good planning can predict crop yields with minimal error rates. Based on past data from catfish farming businesses, catfish pond production results are influenced by several factors including pond area, number of seeds, and amount of feed. The catfish cultivation management system produces predictions of catfish harvest but ignores weather conditions, natural disasters and infectious diseases. The method used in crop yield prediction management is the Tsukamoto Fuzzy inference system. The Tsukamoto method applies monotonous reasoning and rules are built using expert knowledge, enabling the system to be able to conclude and manage predictions of catfish harvest based on data regarding pond size, number of seeds and amount of feed. System testing using 10 data shows prediction results obtained through manual calculations and system calculations, resulting in identical results. Further testing uses the white box method to ensure that the data implemented in the Tsukamoto fuzzy management system accurately produces logical decisions. Hence, it can be concluded that the management system using the Tsukamoto method is able to show effective performance in predicting harvest results based on data on pond area, number of seeds and amount of feed consumption. This management system is expected to be able to provide recommendations for catfish cultivation business planning for the community.

GENETIC DISTANCE REVEALS SYNONYMY AND NEW FISH SPECIES IN BALIKESİR STREAMS, TÜRKİYE

The Mediterranean-Aegean region play a significant role in the context of conserving biodiversity. The protection of endemic and local species becomes attainable only with a thorough understanding of their biology. Specifically, aquatic species dwelling in inland waters may be more vulnerable due to the irregular composition of their habitats, characterized by natural barriers. It becomes imperative to initiate the conservation process by identifying the fauna and flora of ecosystems, thereby facilitating the development of comprehensive conservation plans. In this context, the primary objective of the present study is to identify freshwater fish species inhabiting Madra and Havran Streams in Balıkesir, Türkiye using the DNA barcoding method. The procedure involves DNA isolation through the Chelex protocol, followed by the amplification of the mitochondrial CO1 region using various primer combinations. The results obtained from the gene sequences of 29 individuals in total provide valuable information on species diversity, genetic relationships, and variations. This research emphasizes the importance of DNA barcoding as a valuable tool for species identification, genetic exploration, and conservation plans. The acquired outcomes establish a foundation for the effective management of aquatic biodiversity, particularly within these vulnerable ecosystems.

Strategy for Forming Neighborhood-Based Business Entities as A Motor for Community Economic Potential in Samarinda City, Indonesia

Government administration becomes a key success in developing the local potential sector. Mapping local potential, in this case, sub-districts is one of the important things to do to find and recognize economic potential that can be developed. Ideally, community economic activities at the sub-district level are carried out as institutions or business entities managed professionally but still rely on the area's potential. It can make community businesses more productive and effective. Thus, this study seeks to determine the potential for forming sub-district-based business entities as one of the economic drivers of the city of Samarinda. This study uses a qualitative approach to primary and secondary data. Also, the research location is 59 sub-districts in the city of Samarinda. A total of 59 village heads who were the target of this study, 55 people were willing to answer the questions. The data was analyzed using tabulating interviews through 9 blocks covering the Business Model Canvas components: Customer Segment, Value Proposition, Channel, Customer Relation, Revenue Stream, Key Resources, Key Activities, Key Partnerships, and Cost Structure. Also, Business Model Canvas and SWOT analysis. The result indicates that 10 sub-district-based business models have the most potential to be developed in Samarinda City, namely trading businesses (groceries, restaurants), home industry businesses (weaving, beads, amplang, fish floss, herbal medicine), service businesses (workshops, transportation services, Savings and Loans, motorbike washing, haircuts, sewing), Use of land that is not (RTH), Service-based environmental management system (such as environmental safety and environmental cleanliness), Become a wholesaler, for goods/needs that are for public consumption. Homestead agricultural food sector business (mushroom business, etc.), freshwater fish management, waste recycling, and tourism.

Environmental DNA metabarcoding of freshwater fish in Malaysian tropical rivers using short-read nanopore sequencing as a potential biomonitoring tool.

The approach of combining cost-effective nanopore sequencing and emerging environmental DNA (eDNA) metabarcoding could prove to be a promising tool for biodiversity documentation, especially in Malaysia. Given the substantial funding constraints in recent years, especially in relation to the country's biodiversity, many researchers have been limited to conduct restricted research without extended monitoring periods, potentially hindering comprehensive surveys and could compromise the conservation efforts. Therefore, the present study aimed to evaluate the application of eDNA metabarcoding on freshwater fish using short reads generated through nanopore sequencing. This assessment focused on species detection in three selected rivers within the Endau Rompin Landscape in Malaysia. Additionally, the study compared levels of species detection between eDNA metabarcoding and conventional sampling methods, examined the effectiveness of primer choice, and applied both metabarcoding and shotgun sequencing to the eDNA approach. We successfully identified a total of 22 and 71 species with an identification threshold of >97% and >90%, respectively, through the MinION platform. The eDNA metabarcoding approach detected over 13% more freshwater fish species than when the conventional method was used. Notably, the distinction in freshwater fish detection between eDNA primers for 12S rRNA and cytochrome oxidase I was insignificant. The cost for eDNA metabarcoding proved to be more effective compared to conventional sampling with cost reduction at 33.4%. With favourable cost-effectiveness and increased species detection, eDNA metabarcoding could complement existing methods, enhance holistic diversity documentation for targeted habitats and facilitate effective conservation planning.

Fatty Acid Profile and Escherichia coli and Salmonella sp. Load of Wild-Caught Seaweed Fly Fucellia maritima (Haliday, 1838) (Diptera: Anthomyiidae).

World aquaculture is expected to continue to grow over the next few decades, which amplifies the need for a higher production of sustainable feed ingredients for aquatic animals. Insects are considered good candidates for aquafeed ingredients because of their ability to convert food waste into highly nutritional biomass. However, commercially available terrestrial insect species lack n-3 long-chain polyunsaturated fatty acids (LC-PUFAs), which are essential biomolecules for marine cultured species. Nevertheless, several coastal insect species feature LC-PUFAs in their natural fatty acid (FA) profile. Here, we analysed the lipidic profile of wild-caught seaweed fly Fucellia maritima, with a focus on their FA profile, to evaluate its potential to be used as an aquafeed ingredient, as well as to screen for the presence of pathogenic bacteria. Results showed that the flies had a total lipid content of 13.2% of their total dry weight. The main classes of phospholipids (PLs) recorded were phosphatidylethanolamines (PEs) (60.8%), followed by phosphatidylcholine (PC) (17.1%). The most abundant FA was palmitoleic acid (C16:0) with 34.9% ± 4.3 of total FAs, followed by oleic acid (C18:1) with 30.4% ± 2.3. The FA composition of the flies included essential fatty acids (EFAs) for both freshwater fish, namely linoleic acid (C18:2 n-6) with 3.4% ± 1.3 and alpha-linoleic acid (C18:3 n-3) with 3.4% ± 1.9, and marine fish, namely arachidonic acid (C20:4 n-6) with 1.1% ± 0.3 and eicosapentaenoic acid (C20:5 n-3) with 6.1% ± 1.2. The microbiological analysis found 9.1 colony-forming units per gram (CFU/g) of Enterobacteriaceae and no presence of Salmonella sp. was detected in a sample of 25 g of fresh weight. These findings indicate that Fucellia maritima biomass holds the potential to be used as an additional aquafeed ingredient due to its FA profile and the low count of pathogenic bacteria, which can contribute to the optimal growth of fish and shrimp with a low risk of pathogen transfer during the feed production chain.

Concentrations Fermentation of Rice Bran Addition of Lemuru Fish Oil Toward Fecundity and Production Offspring Moina macrocopa

Moina macrocopa is a natural food that has the potential for freshwater fish seeds, because of its high nutritional value, easy to digest and has a fast, fast breeding, and has a size that is in accordance with the fish's mouth opening. Problems in the use of M. macrocopa as natural food are constrained by the availability of M. macrocopa both from nature and from cultivation. Population density in M. macrocopa cultivation varies due to different quality of food used. The needs of M. macrocopa as natural food can be met if the quality and quantity of feed used optimally support population growth. This study aims to determine the effect of lemuru fish oil concentration in bran suspension fermentation on fecundity and offspring production of M. macrocopa. This study used a completely randomized design (CRD) consisting of five treatments three replications, namely: control treatment (0 mg/L lemuru fish oil, 100 gram bran), P1 (4 mg/L lemuru fish oil, 100 gram bran), P2 (lemuru fish oil 5 mg/L, 100 gram bran ), P3 (lemuru fish oil 6 mg/L, 100 gram bran), P4 (7 mg/L lemuru fish oil, 100 grams), and P5 (8 mg/L lemuru fish oil, 100 gram bran ).The parameters observed were fecundity and child production per parent and water quality. Data analysis used the Analysis of Variance test followed by Duncan's multiple test. The results showed that the cultivation of M. macrocopa using different bran suspension feed with supplemented lemuru fish oil affected the fecundity and production of children per M. macrocopa parent. The concentration of lemuru fish oil of 6 mg/L in the feed resulted in a fecundity of 24,00±2,00 eggs/parent and child production is 20,33±1,52 ind/parent.

Neurotoxic Effects of Imidacloprid on <i>Pethia conchonius</i> (Rosy Barb), a Common Freshwater Fish of India

Insecticides are essential to control arthropod pests in agriculture. However, due to their stability and extended half-lives, they contaminate freshwater aquatic systems like lakes, ponds, and rivers by surface run-offs and leaching. Neonicotinoids are a globally used agricultural pesticides that act as an agonist to the nicotinic acetylcholine receptor (nAChRs) and are known to have harmful effects on non-target organisms like fish. This study aimed to determine the neurotoxic, behavioural, and histopathological effect of three sub-lethal concentrations (SLC I, SLC II, and SLC III) of Imidacloprid (IMI), a neonicotinoid, on the freshwater fish Pethia conchonius. Fish were exposed to IMI for 96 hr, during which their behaviour was recorded, and the brain tissues were collected at 24 hr intervals. Compared to the control group, the IMI-exposed fish showed changes in behaviour, such as jerky, erratic swimming, disequilibrium, and mucus secretion. A significant decrease in Acetylcholinesterase (AChE) activity and histopathological damage were recorded in the brain tissues. The severity of damage and decline in activity was both concentration and time-dependent. The AChE inhibition was observed for SLC III after 96 hr (33.70±2.52) compared to control at 96 hr (84.63±4.25). The optic tectum showed detachment in its layers along with necrosis, and vacuolation. The results indicate that IMI is highly neurotoxic which not only inhibits AChE activity but also causes neural damage in the brain leading to a wide range of behavioural alterations.

Motile Aeromonas Septicemia (MAS) Disease Resistance Test by Aeromonas hydrophila on Triploid Striped Catfish (Pangasianodon hypopthalmus)

Motile Aeromonas Septicemia (MAS) disease caused by Aeromonas hydrophila is a common pathogen that attacks freshwater fish commodities, including triploid as the new strain of striped catfish. This study aimed to test the resistance of triploid striped catfish to MAS infection before being released to farmers as a new commodity to increase national striped catfish production. The test was carried out for two months at the Sukamandi Fish Breeding Research Institute, Subang by injecting A. hydrophila into triploid and diploid striped catfish. The challenge test was carried out by injecting the cultured A. hydrophila with a density of 107 cfu.mL-1 as much as 0.1 mL.ind-1 at fish intramuscularly in all treatments, while in the Control (-) treatment, 0.1 mL of PBS solution was injected.tail-1. The test striped catfish used for each treatment were 10 individuals measuring 9.23 – 9.65 cm, and weighing 7.1 – 9.23 g. Survival parameter data and blood description were analyzed quantitatively using Microsoft Excel 2010 and SPSS version 16.0 software with analysis of variance (ANOVA) at a 95% confidence interval. The results of re-characterization with biochemical tests showed that A. hydrophila were gram-negative, oxidase and catalase positive, motile, could fermentatively convert sugar, and could grow in blood media. The survival of triploid striped catfish after the test was 95%, total erythrocytes on day 7, and total leukocytes on the first day were significantly different from diploid striped catfish. Thus, it can be concluded that striped triploid striped catfish are more resistant to infection with A. hydrophila than diploid.

STRATEGY FOR DEVELOPMENT OF RASBORA GALAXY (DANIO MARGARIATUS) ORNAMENTAL FISH CULTIVATION BUSINESS AT MINA MAKMUR FARM BOJONGSARI DISTRICT, PURBALINGGA REGENCY OF CENTRAL JAVA PROVINCE

Ornamental fish cultivation is a business in the fisheries sector that is quite promising to develop. Market potential and high demand for ornamental fish, especially freshwater ornamental fish, further expand opportunities for developing ornamental fish cultivation. One of the regions with the largest ornamental fish production is Purbalingga Regency.One of the ornamental fish cultivated in Purbalingga Regency is the Rasbora Galaxy fish (Danio Margariatus). As an effort to develop the business of cultivating rasbora galaxy ornamental fish, an approach is needed to formulate the right strategy. One way or approach that can be taken to formulate an appropriate and effective business development strategy is through a SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis. The aim of this research is to determine the technical aspects of cultivating Rasbora Galaxy ornamental fish in Bojongsari District, Purbalingga Regency and identify factors, both internal and external that influence the development of the Rasbora Galaxy ornamental fish business, as well as determining priority business development strategies for the business using analysis. SWOT.The analysis method consists of analyzing internal factors with Internal Factor Evaluation (IFE), and analyzing external factors with External Factor Evaluation (EFE). The results of the IFE analysis obtained a value of0.53and EFE obtained a result of 0.89. The results of the SWOT analysis for this business are in quadrant 1, so the strategy applied is the SO (Strength-Opportunities) strategy. SO strategy is a strategy that utilizes internal strengths to capture existing opportunities

Microplastics and heavy metals in freshwater fish species in the southwestern region of Bangladesh: An emerging concern for public health

Microplastics (MPs) pollution and its associated toxicity raising concerns among scientists as a result of their toxicological impacts on human health and the ecosystem. This study aims to investigate the microplastics and heavy metals (HMs) contamination in seventeen freshwater fish species collected from the Southwestern region of Bangladesh. Microplastics extracted from these species using the hydrogen peroxide digestion method and characterized by Attenuated Total Reflection- Fourier Transform Infrared Spectroscopy (ATR-FTIR). Atomic Absorption Spectrometry (AAS) was used to determine the concentration of HMs in different species for evaluating human health risks. A total of 142 microplastic particles were extracted with an average concentration of 1.13 ± 0.84 items per individual of fish, where the highest microplastics were found in C. punctata (3.43 ± 3.15 items) and lowest in A. mola (0.14 ± 0.38 items). Identified microplastics were dominated by < 1 mm size (87.3%), black color (60.6%), and fiber shape (94.4%). Polyethylene (73.08%), polypropylene (21.15%), and polystyrene (5.77%) were the most prevalent among the identified microplastic polymers. A positive correlation was found between microplastic numbers and fish weight and length. Low to moderate human health risks were associated with microplastics. The concentration (mg/kg) of heavy metals in studied fish samples was Cr (0.47–2.89; 0.79 ± 0.56) > Cu (0.01–1.14; 0.50 ± 0.44) > Pb (0.04–0.58; 0.22 ± 0.12) > Cd (0.00–0.11; 0.03 ± 0.03), respectively. Heavy metals-based human health risk assessment results show that there are no major non-carcinogenic health risks (THI<1), while higher carcinogenic risks are present for consumers.

What do we know about plastic pollution in Brazilian aquatic ecosystems?

Due to the increasing use and inadequate disposal of plastic by humans, aquatic environments have become receptacles for pollutants such as plastic. This study aimed to perform an analysis of plastic particles pollution in Brazilian aquatic ecosystems with special attention to inland aquatic environments and fish in order to identify information gaps in this field. Manuscripts published in the last 21 years and indexed in the Web of Science database were consulted. A total of 185 met the proposed inclusion criteria, such as having empirical data, being conducted in Brazil, and dealing with plastic pollution. In general, the number of studies increases over the years, and this increasing number of publications is accompanied by declared financial support; the Southeast and Northeast regions are the regions that publish the most on the topic, with São Paulo, Rio de Janeiro, and Pernambuco being the main states; the main focus of the studies is the detection of plastic particles mainly in biota (51%) and sediment (34%), and the most frequent ecosystem is the marine (89%); regarding the taxa, the majority is about plastic detection in fish (75%). Only 18% of the papers studying fishes consider their bio-ecological data, and only 17% of the manuscripts carried out the chemical characterization of the particles. However, 99% of the papers considered the shape of the plastic particle. We emphasize the need for more research and grants for studies with Brazilian inland aquatic ecosystems on the effects of plastic particle pollution on freshwater fish. Regional and national research funding agencies are very important to encourage an increase in the number of grants and specific calls for studies on plastic pollution and its impact on freshwater biota, considering the different macro-regions in Brazil, especially in the northern region.

Description of two new species of dactylogirids (Monogenoidea: Dactylogyridae) fromMylossoma albiscopum (Cope, 1872) (Characiformes: Serrasalmidae) from the Peruvian Amazonia.

Two new dactylogyrid monogeneans, Anacanthorus cultro n. sp. and Notozothecium palometae n. sp., are described based on specimens collected from the gill filaments of Mylossoma albiscopum (Cope, 1872) (Characiformes: Serrasalmidae), a pelagic and herbivore teleost collected in the Tigre river, Loreto, Peru. Some monogeneans were stained with Gomori's trichrome and mounted in Canada Balsam to determine internal soft structures. Others were cleared in Hoyer's medium for the study of sclerotized structures. Drawings were made using a drawing tube and a microprojector. Anacanthorus cultro n. sp. is characterized by the presence of a rod-shaped male copulatory organ (MCO) lacking featherlike structures, and a knife-shaped accessory piece with a submedial knob. Notozothecium palometae n. sp. can be distinguished from all congeners by its MCO with a subbasal spur and an accessory piece with inverted hammer shaped. This is the first data on the parasites of M. albiscopum, a popular fish in local markets. Anacanthorus cultro n. sp. is the twenty-fifth documented species of the genus in Peru, while N. palometae n. sp. represents the seventh species of the genus known to infect freshwater fish species in Peru.

Water properties and quality of the largest rice production region in Japan and their influence on the reproduction of zebrafish.

The health of freshwater aquarium fish and their breeding success depend critically on the quality of tap water. In general, tap water in Japan is potable, although the properties of tap water vary among regions in Japan. The city of Niigata is located in the largest rice production region of Japan. We have faced challenges concerning the reproduction of freshwater aquarium fish in Niigata. To determine whether water properties and quality affect the reproduction of aquarium fish in Niigata, we investigated the chemical properties of water and raised zebrafish in water from three different sources, namely tap water of Niigata in May, artificial freshwater (i.e., prepared via reverse osmosis), and natural spring water of Gosen, to document any effects on their sexual maturation and reproduction. We found that the tap water of Niigata was not stable throughout a year (median electrical conductivity = 147.1 μS/cm; SD = 25.6), with springtime lower than the first quartile. We also found that low concentrations of four pesticides in the tap water have been detected in May (max. concentration in 2020, bromobutide 2,000ng/L, butachlor 600ng/L, pyraclonil 200ng/L, ipfencarbazone 20ng/L). Moreover, rearing zebrafish in tap water negatively influenced both fish growth and reproduction: The sex ratio of adults was male biased (proportion of F0 male 70.8%); the average total length (30.5mm) and weight (182mg) of F0 males was decreased; the GSI of F0 females (9.7%) was decreased; the fecundity (the mating success 58.7%; the number of F1 eggs 63.1) of adults was reduced. Rearing in artificial freshwater could improve these outcomes (the sex ratio 55.7%; the total length of F0 males 31.8mm; the weight of F0 males 211mg; the GSI of F0 females 11.7%; the mating success 72.6%; the number of F1 eggs 99.0), whereas rearing in natural spring water from Gosen could improve the sex ratio (56.3%) and the weight of F0 males (200mg), but not the others. Therefore, artificial freshwater made via reverse osmosis should be used for breeding freshwater aquarium fish in rice production region like Niigata. Finally, our results demonstrate that the reproduction of freshwater aquarium fish can serve as a bioindicator of low levels of organic pollutants in tap water and thus provide a basis for evaluating the safety of tap water for human consumption.