Sepetiba Bay is an ecologically and economically significant lagoon for Rio de Janeiro, Brazil. However, the development of this region has been linked to numerous environmental contaminations, leading to the accumulation of trace metals across various ecosystems. Mercury is particularly concerned for public health due to its propensity to bioaccumulate and biomagnify in marine organisms, subsequently entering the human body through consuming contaminated fish. Six studies were identified, with their findings indicating that mercury concentrations in fish from Sepetiba Bay do not exceed the maximum limits set by national legislation (Brazilian Health Regulatory Agency) and the World Health Organization. This systematic review sought to compile research related to mercury contamination in fish from Sepetiba Bay between 2000 and 2024, following the PRISMA-P protocol. A total of six studies were selected, with an additional 27 articles included because of their relevance in understanding the feeding habits of fish, bringing the total to 33 articles. Our findings suggest that, despite the low risk to human consumption, there is a need for the development of public policies focused on the continuous monitoring and control of mercury contamination in the bay’s fish, intending to decontaminate the environment and prevent a progressive increase in mercury levels in species that constitute a significant part of the local diet.
Ultrasonography is a fast and non-invasive method that offers a promising alternative for sex identification and gonadal maturation assessment in fish. This technique is especially relevant to Brazilian sardine (Sardinella brasiliensis), a species of high commercial value whose small body makes traditional sexing methods unfeasible. Ultrasonography was applied to 55 individuals undergoing their first gonadal maturation. All fish were anesthetized for examination and subsequently euthanized for macroscopic evaluation to confirm sex and determine the maturation phase. These findings were supported by histological analysis, which confirmed the accuracy of the results. Ultrasonography using a multifrequency transducer (8–13 MHz) achieved 98% accuracy in sex identification, and 46 males and nine females were identified. Histological examination revealed 32 reproductively capable males (phase C) and 14 immature individuals (phase A), while all females were classified as phase C (ready for reproduction and spawning). Although ultrasonography proved effective for sex differentiation, it showed limitations in determining gonadal maturation phases. Further studies and the development of a specific protocol are required for accurate phase classification. Therefore, ultrasonography demonstrates great potential as a practical and effective tool in reproductive monitoring. This study is the first report of its application to the Brazilian sardine.
Understanding the impact of exploitation patterns on yields is crucial for ensuring the sustainability of fishing activities. However, data availability can hamper the assessment of how close resources are to optimal exploitation. We gathered simple life history parameters of shrimp stocks in Brazil using published data and applied a yield per recruit model to determine the optimal combinations of first catch length and fishing mortality for maximizing yields. We evaluated five marine shrimp species, Farfantepenaeus subtilis, F. brasiliensis, F. paulensis, Xiphopenaeus kroyeri, and Litopenaeus schmitti, distributed across four major Brazilian regions (North, Northeast, Southeast, and South). A clear pattern emerged: stocks in Northeast demonstrated high yields with appropriate first catch lengths and fishing mortality rates, with only some cases 12% below the optimum level. In contrast, the Southeast region presented more concerning situations. Its fisheries employed very small first catch lengths, capturing individuals at early life stages, below the length of first maturation, harming reproduction and stock replenishment. Combined with high fishing mortality rates, this resulted in yields 37% below the optimal, indicating signs of growth overfishing.
The pirarucu (Arapaima gigas) is native to the Amazon basin, but in Rondônia, Brazil, it occurs naturally only in the far north. For multiple reasons, it has become an invasive alien species in this biome and in other Brazilian states, with reported impacts on biodiversity and the food security of riverine populations. This study developed a management technique for the control/eradication of invasive pirarucu, based on the sustainable management of native pirarucu in Mamirauá, Amazonas, Brazil. After adaptation, eradication management was implemented and validated with riverine communities of the Cautário River. Between 2022 and 2024, 126 residents were trained as managers to monitor populations and conduct managed fisheries under the supervision of environmental agencies. The process also structured a production chain for commercializing invasive pirarucu. In total, 633 pirarucu were captured, generating R$ 302,916.54 (US$ 58,417.20) for local communities. Thus, invasive pirarucu management can reduce its populations and provide supplementary income to riverine communities, strengthening local bioeconomy and governance initiatives. Continued fishing and systematic population monitoring in the coming years are necessary to evaluate management effectiveness and deepen investigations into invasions and socio-environmental impacts in protected Amazonian areas.
The genus Prochilodus is an important fish resource. The various species within this genus are morphologically very similar, making reliable taxonomic identification difficult and creating uncertainty regarding the exact status of the different forms. This study aimed to evaluate the genetic differentiation between two species of Prochilodus belonging to the same lineage from the Maranhão and Amazon River basins based on mitochondrial DNA markers (16S rRNA, COI, Cyt b) and nuclear (TROP) DNA sequences. A total of 151 samples were collected from the Maranhão and Amazon rivers, followed by DNA extraction, polymerase chain reaction, sequencing, and data analysis, with the gene fragments analyzed separately and concatenated. The results revealed a strong genetic similarity between the species, with low genetic divergence values (0 to 0.35%) for the genes under study.
This study characterizes the bycatch associated with Arapaima gigas fisheries in the Cautário River, Rondônia, Brazil, where the species occurs as an invasive species. Fisheries monitoring was conducted during the low-water period (August to October 2025), when A. gigas capture rates intensify. During this period, 69 bycatch individuals were recorded, belonging to nine species, distributed in seven families and eight orders. Vertebrates were predominant, with reptiles and fish accounting for more than 68% of the incidental captures. The turtle Podocnemis unifilis was the most frequent species (36.23%), followed by the fish Colossoma macropomum (31.88%) and Phractocephalus hemioliopterus (11.59%). The limnological parameters remained within ranges compatible with the sampled aquatic environments and favorable to the occurrence of non-target species recorded in the fisheries. The results indicated that the high taxonomic diversity and representation of non-target species reflect the low selectivity of the fishing gear used in A. gigas fisheries. These findings highlight the importance of continuous monitoring of the bycatch as an essential tool for the adaptive management of A. gigas fisheries in the Cautário River, part of the Guaporé River basin.
Docosahexaenoic acid (DHA) was the major polyunsaturated fatty acid (PUFA) in the sperm plasma membrane, and the levels of PUFAs decreased in treated groups during the cryopreservation process. The supplementation of TT (Tribulus terrestris) to Cyprinus carpio sperm at 200 µg∙L-1 positively affected the maintenance of motility parameters and FAs levels after the freeze-thaw cycle, and TT can be used as an herbal medicine instead of synthetic pharmaceuticals to improve the productive performance in aquaculture.
Amazonian people are highly dependent on fishing, which provides their main source of protein. Fishing in the middle Caeté, Eastern Amazon, Pará, Brazil, was described in terms of the sociodemographic profile of fishers, gear, and strategies used in catches. Semi-structured interviews were conducted with fishers in the region. Fishing occurs throughout the year, and to a lesser extent during the closed season. It is characterized as subsistence fishing, although a small percentage (20%) sell part of their catch to supplement their income. Fishing gear is diverse and varies according to the seasons, with gillnets and set longlines being the most common. Transportation is carried out aboard small canoes powered by oars or outboard motors. The most important commercialized species are the giant Malaysian prawn, dourada, and piramutaba, while traíra, mandií, tuvi, anujá, aracu, piranha, among others, are intended for family consumption. A change in fishers’ habits is expected in terms of increasing the mesh size of gillnets to be more selective and to comply with fishing regulations.
Fisheries impact aquatic resources, with many species taken as bycatch, and thus represent a global threat to many species, in prticular, the elasmobranchs. Given the lack of reliable bycatch data, this study conducted a systematic review in four scientific databases to identify publications addressing elasmobranch bycatch along the Amazon coast. Between 2002 and 2022, 27 studies were published, docummenting the bycatch 28 sharks and 14 rays species. The literature search revealed an increase in the frequency of publication after 2015, with Brazil dominating the research output, while neighboring countries contributed limited data. Most studies involved trawling, while gillnet and longline fisheries were poorly represented. Worldwide, 78.0% of sharks and 57.0% of rays are classified as threatened. The review reveals persistent problems, including deficiencies in the identification, delays in data publication, and weak monitoring and enforcement. These findings emphasize the urgent need for improved research coverage, monitoring, and conservations actions.
This study evaluated biosecurity practices in five tilapia fry hatcheries in the Federal District, Brazil, between August 2023 and August 2024. Data analysis showed high compliance in water quality monitoring, feed management, and mortality records, but weaknesses in quarantine, visitor control, use of personal protective equipment, pest control, and sanitary fallowing. No significant differences were observed among thematic groups (p > 0.05), although variation among farms was detected (p < 0.001). Biosecurity adoption is partial and non-standardized, highlighting the need for improved protocols and management practices.
Macrobrachium acanthurus and M. olfersii have been widely studied, with M. acanthurus recognized for its aquaculture potential. Both species exhibit an amphidromous life cycle, in which larvae migrate to brackish waters to complete their development. This study evaluated the effect of salinity on early larval survival, testing two hypotheses: 1) that gradual acclimation to lower salinities increases short-term survival; and 2) that there is an optimal salinity range for larval survival. Two experiments were conducted. The first evaluated the short-term survival of M. olfersii larvae during gradual acclimation from freshwater to different salinities (0, 6, 11, 14, 20, and 24 g/L). Survival was high (86–94%) and showed no significant differences among treatments, rejecting the first hypothesis but confirming the effectiveness of the acclimation protocol. The second experiment evaluated the long-term survival of both species at salinities of 0, 6, 12, 16, 22, and 28 g/L. Survival was significantly influenced by salinity, with higher mortality at the extremes and better performance at intermediate levels. Nevertheless, the overall decline indicates that successful larviculture depends on the interaction between salinity, nutrition, and other environmental factors.
This study aimed to establish length–weight relationships (LWR) for fish species captured by the artisanal fleet on the central coast of Espírito Santo, Brazil. Although the landing site was specific, the fish were caught across various areas along the central coast, indicating a broader spatial range than the collection point suggests. Data were collected from February 2023 to July 2024, including fishing gear used, capture location, total length (TL), and total weight (TW) of the specimens. A total of 1,484 individuals were measured, representing 12 species from six orders and 10 families. Haemulidae was the most represented family, and Haemulon aurolineatum was the most abundant species. Caranx crysos and Balistes capriscus showed the highest mean lengths (35.50 and 34.59 cm), while H. aurolineatum and Cynoscion jamaicensis had the lowest (20.39 and 22.99 cm). Caranx crysos and Cephalopholis fulva were the only species exhibiting isometric and allometric growth, respectively (b = 2.94; b = 3.08). The remaining species showed negative allometric growth, with a ranging from 0.006 to 3.798, b from 1.152 to 3.08, and r2 from 0.4758 to 0.9636. These results provide biological information for key commercial species and support actions for sustainable fisheries management and conservation in Espírito Santo.
This study investigated the potential use of fermented grape pomace (FerGP) as a dietary ingredient for juvenile mullet (Mugil liza). For this purpose, growth perfomance, hepatic lipid peroxidation, and hematology of juvenile mullet fed various levels of FerGP were evaluated. A total of 225 fish (0.57 ± 0.01 g) were randomly distributed into 15 tanks and fed ad libitum three times a day for 65 days with different levels of FerGP (2.5, 5, 10, and 15%). There were no significant differences (p > 0.05) in hematological parameters. Regarding the zootechnical parameters, FerGP 15% showed higher specific growth rate compared to the other treatments. Dietary inclusion of FerGP significantly reduced hepatic lipid peroxidation, as indicated by a decrease in thiobarbituric acid reactive substances (TBARS) values. The results demonstrated that the inclusion of FerGP in the diet is feasible and safe, promoting benefits to the productive performance of juvenile mullet.
This study aimed to evaluate the impact of delayed Artemia nauplii introduction on the larviculture of the Amazonian ornamental fish Pyrrhulina brevis. A completely randomized design with four treatments and four replicates was implemented. Larvae were subjected to varying delays in Artemia nauplii supply: 0 (no delay), 2, 4, and 6 days and were subsequently fed until the end of the 20-day experimental period. Growth performance, point-of-no-return (PNR), and intestinal and muscular histomorphometry were assessed at the end of the experiment. No differences in length, weight, or uniformity were observed between larvae with no delay and those with a 2-day delay in Artemia nauplii supply (p>0.05). However, total mortality occurred in larvae exposed to delays of 4 days or longer by the fifth day of experiment. Larvae without delay exhibited a survival rate of 86.25%, significantly higher than the 20% survival rate in those subjected to a 2-day delay (p<0.05). The PNR for P. brevis larvae was determined to be 2.69 days (9.69 days post-hatching). No differences were observed in intestinal or muscle histomorphometry among treatments (p>0.05). These findings highlight that delaying Artemia nauplii supply critically reduces the survival of P. brevis larvae, potentially compromising the viability of larviculture production.
Based on the river continuum and flood pulse concepts, this study investigated the seasonal, spatial and limnological effects on fish assemblage distribution along the São Miguel River, Amazon basin, Brazil. Fish were sampled and environmental variables measured during the high- and low-water periods in upper, middle and lower sections of the river. The results revealed significant spatial and seasonal effects, as well as interactions between spatial and temporal gradients, which bring about distinct differences in assemblage composition. These patterns were associated with variations in limnological parameters along a longitudinal gradient. Species distribution and turnover were shaped by both the flood pulse and the spatial gradient, which are processes that drive environmental changes and influence trophic resource dynamics – key factors for species occurrence. Overall, our findings indicate that the structure of the fish assemblages in the São Miguel River is shaped by hydrological variation, with the flood pulse being the primary regulating factor of the taxonomic composition of the ichthyofauna.
Small-scale fisheries are essential for livelihoods, food security, and income generation. However, information on fishing in lagoon environments in Brazil is scarce and historically neglected, leaving this sector on the margins of management actions and public policies. This paper describes the experience of applying participatory methods to reveal the fisheries and fishing activities carried out between 2019 and 2023 in the Piratininga-Itaipu Lagoon System, in the metropolitan region of Rio de Janeiro, southeastern Brazil. The work included three stages: exploratory phase and fishers' engagement, assisted fisheries self-monitoring program, and fishers' validation and results assessment. The results showed that 40 fishers and 25 boats actively participate in the fisheries. The total production landed in 2022 was 52.2 tons, corresponding to 16.5 kg/hectare/year and 1,305.8 kg/fisher/year. These results indicated the socio-economic importance of the activity, contributing to the conquest of the right to territory by the Piratininga lagoon fishers. The effectiveness of the participatory techniques used reinforces the importance of collaboration between fishers and researchers in consolidating information on the lagoon fisheries systems.
The aim of this study was to evaluate the performance of Penaeus vannamei and Oreochromis niloticus in an integrated multi-trophic system with biofloc technology using different strategies. Two treatments were developed: TC (chemoautotrophic) and TH (heterotrophic). The TC treatment started 46 days before stocking the animals, with inorganic fertilization. In the TH treatment, organic fertilization was carried out after stocking the animals. Four hundred shrimp m-2 (1.00 +/- 0.04 g) and 45 tilapia fry m-3 (25 +/- 0.50 g) were stocked for 86 days. Water quality parameters such as temperature, oxygen, and pH were monitored daily. Total ammonia, nitrite, nitrate, phosphate, total suspended solids, and settleable solids were monitored twice a week. Prior fertilization in the chemoautotrophic treatment avoided high concentrations ofnitrogen compounds in the system, due to the prior establishment ofbacteria, compared to the heterotrophic treatment. The increase in nitrogen compounds in heterotrophic treatmentled to higher water use, reduction in feed and consequently lower shrimp growth performance compared to the chemoautotrophic system. Tilapia's growth was not affected. Therefore, the use of prior fertilization in chemoautotrophic treatment allowed for a higher final weight, yield of shrimp, and greater environmental sustainability.
This study aimed to investigate the seasonal variation in the presence of plastic fragments in the digestive system of Mylossoma duriventre, a species that is both abundant and commercially significant in the Juru & aacute; River Valley, state of Acre, Brazil. Two collections were conducted, the first in March 2024 and the second in July-August 2024, in the municipality of Cruzeiro do Sul, state of Acre. Our findings indicated that hydroclimatic factors play a crucial role in the occurrence of microplastics in M. duriventre, with a notable increase in fiber ingestion during the highwater period. These results contribute to a deeper understanding of the environmental risks associated with microplastics and highlight their biological consequences. In addition, this study aimed to raise awareness of the urgent need to reduce plastic usage and implement responsible waste disposal practices.
Arapaima gigas is the largest scaled freshwater fish in the world and can grow to more than 3 meters in length and exceed 252 kg. This species naturally inhabits the flooded areas of the Amazon basin, but it has been found outside this region as a result of intentional or accidental human actions. In this study, we analyzed the items consumed by the A. gigas distributed in the Caut & aacute;rio River, a tributary of the Guapor & eacute; River Basin (Rond & ocirc;nia, Brazil), in which pirarucu is not native and requires actions for its eradication. Experimental fisheries were conducted from August 2023 to September 2024. A total of 128 A. gigas were captured (ranging from 1.16 to 2.26 m, with a mean of 1.76 +/- 0.31 m, and weight of 24.70 to 111.60 kg, with a mean of 52.37 +/- 22.54 kg) and had their stomachs analyzed. It was observed that 104 stomachs were full and 24 were empty. In the stomachs, five categories of food items were classified: fish and fish remains, plant material, debris, crustaceans, and worms. The items with the highest absolute frequency were plant materials (82), fish and fish remain (51), worms (32), and crustaceans (1). It was concluded that the A. gigas of the Caut & aacute;rio River Basin feed mainly on fish, but with a large participation in the diet of plant materials, which may be an indication of involuntary ingestion due to the animal's voracity or possible onset of food shortages in the study region.
This study evaluated the effects of astaxanthin from Haematococcus pluvialis on coloration, antioxidant activity, and growth performance in Cryptocentrus cinctus. Three dietary treatments were formulated with increasing astaxanthin concentrations: A0 (0%-control), A10 (0.01% of the total dry diet), and A15 (0.015% of the total dry diet). Astaxanthin supplementation significantly enhanced skin pigmentation, with A15 fish exhibiting a distinct yellow coloration (R = 144.75; G = 122.9; B = 48.5). Catalase activity was also the highest in the A15 group (25 UCAT mg-1), suggesting improved antioxidant capacity. Zootechnical performance improved with astaxanthin inclusion, as A15 fish demonstrated greater weight gain (0.44 g), length gain (7.93 mm), and a lower feed conversion ratio (1.10). Overall, dietary supplementation with 0.015% astaxanthin from H. pluvialis enhanced pigmentation, antioxidant response, and growth efficiency in C. cinctus, representing the first report of carotenoid supplementation for this species.
