Search Results (373)

Small pelagic fish, including sardines, are essential to global fisheries and aquaculture feed production. However, these species are increasingly exposed to intense exploitation. In Chile, the common sardine (Strangomera bentincki), endemic to the Humboldt Current System, supports major industrial and artisanal fisheries. Landings are expected to reach 300,000 tons by 2025, mostly for fishmeal production. As a keystone species, S. bentincki is highly sensitive to environmental variability during early development, which can reduce recruitment and threaten long-term population sustainability. This interdisciplinary approach integrates ecological and biotechnological perspectives to assess the feasibility of controlled juvenile sardine production in land-based Ecological Aquaculture (EA) systems, including Recirculating Aquaculture Systems (RAS) and Integrated Multi-Trophic Aquaculture (IMTA), which are designed to reduce environmental impacts. These systems enable precise control of temperature, feeding regimes, and water quality, facilitating investigations into larval and juvenile survival, growth performance, and physiological responses under variable thermal and nutritional conditions. Emphasis is placed on fatty acid metabolism during ontogeny, particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), which are essential for somatic growth, reproductive development, and thermal tolerance. Developing standardized protocols for juvenile S. bentincki culture addresses key gaps in husbandry and physiology (temperature threshold, nutrient density, larval growth rate, etc.) while introducing a novel ecological–aquaculture integration framework. This approach links early-life ecology with applied rearing techniques to support stock enhancement, strengthen artisanal fisheries, and promote sustainable aquaculture diversification under increasing environmental variability. Full article

Background/Objectives: Acute promyelocytic leukemia (APL) is a medical emergency associated with life-threatening complications such as disseminated intravascular coagulation (DIC), necessitating prompt therapeutic intervention and rapid diagnostic confirmation. APL is characterized by a translocation of the PML gene (15q24) with the RARA gene (17q21), resulting in the PML::RARA fusion gene on the derivative chromosome 15. Atypical PML::RARA rearrangements may escape detection by standard FISH probes. This study highlights limitations of commonly used probe sets and underscores the need for alternative FISH probe sets and complementary molecular testing. Methods: Two unique APL cases with atypical PML::RARA rearrangements were identified in our laboratory. Each case was evaluated at diagnosis using two commercially available FISH probe sets from Abbott Molecular and Cytocell. Metaphase FISH was performed to characterize the atypical FISH signal pattern further, and qRT-PCR was used to confirm the presence of the PML::RARA transcript. Results: Both cases demonstrated atypical rearrangements with a single fusion signal. In the first case, the Abbott probe detected a single fusion signal, while the Cytocell probe was negative. Metaphase FISH revealed an insertion of the PML region near RARA on chromosome 17. In the second case, the Cytocell probe was positive, and the Abbott probe was negative; metaphase FISH demonstrated insertion of the RARA region near PML on chromosome 15. qRT-PCR confirmed the presence of the PML::RARA transcript in both cases. Conclusions: These findings reveal limitations in commonly used PML::RARA FISH probes and support reflex testing with alternative probes and molecular confirmation to ensure accurate diagnosis. Full article

Extreme weather events, particularly marine heatwaves (MHWs), increasingly threaten aquaculture systems worldwide by impairing animal physiology and economical sustainability. This showcases the need to develop nutritional approaches that enhance animal performance under sub-optimal conditions. This study evaluated the effects of dietary supplementation with the brown macroalga Laminaria digitata (whole dried powder or extract) on the antioxidant status, digestive activity, and lipid metabolism of juvenile Sparus aurata exposed to a simulated MHW. Fish were fed four diets (control, 0.3% extract, and 0.3% or 1.5% powder) for 30 days before being exposed to a category III Mediterranean MHW. Under optimal temperature, macroalgae supplementation reduced oxidative status (lower catalase activity). The powder-feeds decreased lipid peroxidation, while the extract-feed elicited the opposite. All supplemented diets reduced proteolytic activity, and the extract-feed also decreased amylase activity. The MHW impaired gastrointestinal antioxidant defenses and liver lipid metabolism, decreasing catalase and glutathione S-transferase activities, as well as ΣPUFA n-6, 16:1 n-7, and 18:2 n-6 levels. The 0.3% powder-feed mitigated MHW-induced reductions in antioxidant activity, while both 0.3%-diets prevented thermal stress-related alterations on fatty acid profile. Overall, L. digitata powder at 0.3% was most effective at enhancing thermal stress resilience, supporting its value as a functional aquafeed ingredient. Full article

Pollution in aquatic ecosystems is intensifying under the combined pressures of climate change and anthropogenic contaminants, with nanoplastics (NPs) emerging as a critical threat to fish reproduction. Although extensive research has demonstrated the physiological impacts of NPs, their direct effects on sperm quality and functionality remain poorly characterized. This review synthesizes evidence from original research articles that specifically examined NPs’ impacts on fish sperm quality and related reproductive endpoints. The findings reveal that NPs consistently impair sperm motility, viability, and fertilization capacity, while inducing oxidative stress, DNA damage, mitochondrial dysfunction, and endocrine disruption. Particle size, surface chemistry, and exposure route were identified as key determinants of toxicity, with direct sperm exposure causing immediate impairments and chronic or maternal transfer exposures leading to systemic and transgenerational effects. Notably, several studies reported reduced offspring survival, altered development, and disrupted gene expression, highlighting the intergenerational risks of NPs contamination. Despite these advances, significant knowledge gaps remain, including limited research on marine wild and cultured fish species, the effects of diverse life histories on NPs toxicity, environmentally relevant exposure levels, and the combined effects of NPs with other stressors. Overall, this review underscores that fish sperm are highly sensitive to NPs pollution, with consequences that extend across generations and threaten population stability, calling for urgent mechanistic and ecologically realistic investigations. Full article

Understanding life history parameters is key to assessing demography, biological productivity, and extinction risk of fishes. Age and growth analyses in chondrichthyan fishes (sharks, rays, and ghost sharks) is primarily undertaken through counting vertebral band pairs. For rare, threatened, and protected species such as river sharks (Carcharhinidae; Glyphis), obtaining sufficient vertebrae samples may not be possible. Here we use a very small sample size, selective size-class sampling, back-calculation techniques, and a Bayesian hierarchical model that accounts for repeated measures to provide age and growth information for the Speartooth Shark Glyphis glyphis from which comprehensive sampling is not possible. Ten individuals were selectively sampled from the Adelaide River, Northern Territory, Australia. Bayesian length-at-age models using a combination of informative and uninformative priors in a multi-model framework were applied to the observed and back-calculated data with the sexes combined. Band pair counts produced age estimates of 0–11 years and suggest that age at maturity is possibly >12 years. Most model parameter estimates for length-at-birth (L₀) and asymptotic length (L_∞) were biologically plausible. The Gompertz growth function, applied through a Bayesian hierarchical approach to back-calculated data, provided the best fitting and most biologically appropriate length-at-age parameters: L_∞ = 229.5 cm TL ± (14.6 SE), g_Gom = 0.16 yr⁻¹ ± (0.01 SE), and L₀ = 58.2 cm TL ± (1.4 SE). The results presented here are the first study to apply Bayesian methods to back-calculated length-at-age data while accounting for repeated measures. Full article

Conventional alligator farming, characterized by reliance on chilled fish meat, faces significant challenges, including risks of bacterial contamination and nutritional imbalances. These issues heighten increasing disease susceptibility and threaten industry sustainability, underscoring the critical need for developing nutrient-dense, low-pathogenicity compound feeds. This study conducted a comparative analysis of newborn Siamese crocodiles fed either chilled fish meat or compound feed formulation. Intestinal microbial samples from both cohorts underwent 16S rRNA gene high-throughput sequencing to evaluate differences in microbial composition, diversity, and predicted functionality. The compound feed, specifically formulated for this investigation, possessed the following nutritional composition: crude protein 52.42%; digestible crude protein/digestible energy 16 mg/kcal; crude fat 12.31%; ash 17.42%; crude fiber 0.45%; starch 7.69%; digestible energy 3450 kcal/kg; lysine 3.66%; threonine 1.92%; methionine 1.27%; arginine 3.07%; total essential amino acids 22.97%; calcium 2.51%; total phosphorus 1.8%; available phosphorus 0.98%. Bioinformatics analysis revealed that the compound feed group exhibited numerically higher richness and alpha diversity indices within the intestinal microbiota compared to the chilled fish group. The microbial communities in both groups were dominated by the phyla Proteobacteria, Bacteroidetes, Fusobacteriota, and Firmicutes, collectively representing over 50% of the relative abundance. Functional prediction indicated that the compound feed group possessed the highest relative abundance in metabolic pathways associated with cofactor and vitamin metabolism, carbohydrate metabolism, amino acid metabolism, terpenoid and polyketide metabolism, lipid metabolism, and replication and repair. In contrast, the chilled fish group exhibited significant functional alterations in glycan biosynthesis and metabolism, translation, nucleotide metabolism, transcription, and biosynthesis of other secondary metabolites. Histomorphological analysis demonstrated greater villus height and crypt depth in the compound diet group compared to chilled fish group, although no significant differences were observed in crypt depth or the villus-to-crypt depth ratio. Collectively, these findings indicate that the compound feed enhances intestinal microbial diversity and optimizes its functional structure. Furthermore, while no statistically significant difference in small intestinal villus height was detected, the results suggest a potential positive influence on intestinal development. This investigation provides a scientific foundation for compound feed development, supporting sustainable breeding practices for Siamese crocodiles. Full article

Yueqing Bay in China supports important marine resources that sustain local fisheries and food security, but increasing anthropogenic pressures and natural environmental changes threaten its biodiversity. This study used morphological identification, COI DNA barcoding, and 12S DNA metabarcoding to assess ichthyoplankton composition and fish spawning patterns. A total of 13,415 eggs and 17,291 larvae were collected using horizontal and vertical plankton nets. Morphological analysis identified 58 taxa, while molecular methods detected 21 species (COI) and 48 species (12S), with an overall total of 105 species from 78 genera and 42 families. Spawning activity showed clear seasonal and spatial patterns, with the highest abundance and diversity in spring and summer, particularly around Ximen Island and the Bay mouth. These areas function as key spawning and nursery grounds. 12S DNA metabarcoding contributed strongly to species detection, especially for cryptic and morphologically indistinguishable larvae, complementing traditional surveys. The findings provide essential baseline information for monitoring fish stocks, protecting critical habitats, and improving fishery management strategies under increasing anthropogenic and climate-related pressures in Yueqing Bay. Full article

The endangered freshwater fish Gobiobotia brevibarba is endemic to Korea and threatened by habitat disturbance in major river systems. We investigated four wild populations from the Han River basin (IJR, BHR, NHR) and the Geum River basin (GR) using eleven microsatellite loci to assess genetic diversity, population structure, and contemporary gene flow. All populations showed relatively high genetic diversity (H_O = 0.709–0.800, H_E = 0.707–0.803) and no evidence of inbreeding, although bottleneck signals under the infinite allele mutation model were detected in IJR and BHR. Contemporary effective population size was large in IJR (N_e = 2463) and moderate in NHR (N_e = 467), whereas estimates for BHR and GR were imprecise. Genetic differentiation was very low within the Han River basin (F_ST = 0.009–0.027) but weak and significant between Han and Geum (F_ST = 0.085–0.096), and clustering analyses (STRUCTURE, DAPC, find.cluster) consistently supported K = 2, separating Han from Geum River. Gene flow analyses indicated extremely limited interbasin gene flow (<4%) but asymmetric contemporary migration from BHR into both IJR and NHR; all other migration rates were similarly low. These results show that G. brevibarba currently maintains high genetic diversity and two basin-level genetic clusters, underscoring the need to manage Han and Geum River populations as separate units and conserve riffle habitats and longitudinal connectivity. Full article

The status of the fishery resources in Poyang Lake, China, during periods of abnormal drought was examined using a comparative analysis of data from four fishery resource surveys performed during 2022 and 2023, in the first half (April–June) and the second half (September–November) of each year. A total of 91 fish species (11 orders, 17 families, 54 genera) were collected, with Cyprinidae accounting for 54.95% of the total species and Megalobrama skolkovii, Aristichthys nobilis, and Hypophthalmichthys molitrix as the dominant species. The Shannon-Weiner diversity, Pielou evenness, Simpson diversity, and Margalef richness indices were 3.30, 0.73, 0.95, and 6.93, respectively. The corresponding catch per unit effort (CPUE) values of the fish were 5.49 kg·(1000 m²·h)⁻¹, 4.45 kg·(1000 m²·h)⁻¹, 3.03 kg·(1000 m²·h)⁻¹, and 2.75 kg·(1000 m²·h)⁻¹, showing a clear decreasing trend across the successive sampling periods. The abnormal drought did not cause significant differences in the number of fish species and diversity indices (p > 0.05), but altered the fish community structure, characterized by reduced dominance of small, sedentary, and herbivorous fish, and led to a significant decline in CPUE (p < 0.05). This demonstrates that abnormal hydrological regimes can undermine the effectiveness of the 10-year fishing ban and threaten the recovery of fishery resources in river-connected lakes. Full article

Shrimp populations are threatened by overfishing and climate change. Despite this, there are limited studies on the variations in biomass, number, and size of Eastern Neptune rose shrimp, Parapenaeus fissuroides, in different fishing grounds across seasons in the Southern Yellow and East China Seas of China, as well as habitat area change under different climate scenarios. In this study, the data was obtained from the bottom trawling surveys conducted from November 2018 to September 2019 at 26.5–35° N 120–127° E. We found that the major cohorts were concentrated at depths of 70–110 m in spring and summer, 80–90 m in autumn, and 60–100 m in winter. The greatest abundance was observed at sea bottom temperatures of 18–20 °C in spring, 18–21 °C in summer, 19–22 °C in autumn, and 17–19 °C in winter; and sea bottom salinity levels of 34–35 across all four seasons, indicating the influence of high-salinity Taiwan Warm Current and Yellow Sea Warm Current. The annual mean catch per unit effort in weight and number were 16,623.65 g·h⁻¹ and 4304.525 ind·h⁻¹, respectively. Climate variations may negatively impact the habitat area range of P. fissuroides. For migration route, P. fissuroides concentrates in Yushan and Yuwai for the upcoming spawning season in spring, with offspring occurring in high-temperature and high-salinity waters of Zhouwai and Yuwai in summer. The newborn recruited cohorts remained in Yushan, Wentai, and Mindong for nursery grounds in autumn and winter. We suggested a seasonal closure from August to November in Yushan, Yuwai, Zhouwai, and Mindong to protect and conserve P. fissuroides populations. Full article

The cDNA sequences of the common gonadotrophic hormone α-subunit (ag-Gthα) and of the specific follicle-stimulating hormone β-subunit (ag-Fshβ) of the giant Amazonian fish Arapaima gigas have been previously isolated by our research group. A synthesis of ag-Fsh in HEK293 cells and its purification and preliminary characterization were also carried out. In the present work, ag-Fsh was obtained and purified from the same host cells, and an extensive physical chemical characterization was performed via RP-HPLC, HPSEC, and MALDI-TOF-MS. Ag-Fsh, when compared to human FSH (hFSH), showed a higher hydrophobicity by RP-HPLC and a higher molecular mass (MM) via HPSEC. The same higher MM was also confirmed via MALDI-TOF-MS: 35,353 Da for ag-FSH against 31,969 Da for hFSH. Its immunological activity was also confirmed via an hFSH ELISA, in comparison with the highly purified pituitary preparation of hFSH-AFP7298A, from the National Hormone and Pituitary Program (NHPP-USA), with a clear response that was, however, 1560-fold lower when compared to the purest preparation. Finally, an in vitro bioassay, based on the stimulated release of 11-ketotestosterone (11-KT) from immature A. gigas testis, quantified ag-Fsh biological activity in comparison with human chorionic gonadotropin (hCG) and with human pituitary FSH-AFP7298A, showing a potency clearly higher than that of hCG. This suggests that injections of ag-Fsh in A. gigas and ag-Fsh cDNA gene therapy applications could be used for improving the reproductive functions of this threatened species. Full article

The skin of vertebrates serves as a crucial interface with the external environment. In fish, it performs various functions, mainly offering protection against pathogens through the action of specialized cells. Cyclostomes, such as hagfish, lack scales and rely heavily on mucus for defense. These jawless vertebrates possess specialized glands that produce a unique mucous exudate when threatened, forming a thick slime that can clog the gills of predators. This substance, composed of mucus and filamentous proteins, offers hagfish a distinct evolutionary advantage and may explain their survival among extinct agnates. These proteins are produced in the cytoplasm of epidermal thread cells, which are unique to hagfish and contain coiled, intermediate filaments. Despite extensive research on thread cell morphology, their roles remain poorly understood. This study investigates the putative defense function of epidermal thread cells in three hagfish species, Eptatretus cirrhatus (J. R. Forster, 1801), Eptatretus stoutii (Lockington, 1878), and Myxine glutinosa (Linnaeus, 1758), using immunohistochemistry, confocal microscopy, and bioinformatics techniques to better understand their contribution to hagfish immunity and ecological resilience. Full article

Microplastics threaten freshwater fish health, with probiotics potentially alleviating this stress. This study subjected Opsariichthys bidens fry to 10 μg/L polystyrene microplastics (diameter 100 μm) for seven days, then established control (CK, 0 CFU/g), low (LC, 1 × 10⁷ CFU/g), medium (MC, 1 × 10⁸ CFU/g), and high (HC, 1 × 10⁹ CFU/g) Bacillus coagulans supplementation groups for a 56−day rearing experiment. Results indicated that microplastic stress significantly reduced intestinal digestive enzyme activity in O. bidens and induced oxidative stress. Following stress removal, probiotic-treated groups exhibited markedly superior growth performance compared to the control (CK). Notably, the high-concentration probiotic group (HC) demonstrated intestinal trypsin levels approaching pre-stress levels, with no significant differences in liver antioxidant capacity (T−AOC, CAT, SOD) compared to pre-stress levels (p > 0.05). Furthermore, compared to the control group (CK), probiotic-treated fish exhibited upregulated growth- and immune-related genes (igf, ghr, tnf−α, il−1β), alongside optimized gut microbiota composition, characterized by increased abundance of Bacillus and decreased abundance of Pseudomonas and Aeromonas. This study demonstrates that B. coagulans alleviates microplastic-induced stress in O. bidens, offering insights for aquatic ecosystem conservation and biological remediation of microplastic pollution. Full article

Aquatic ecosystems are increasingly threatened by multiple anthropogenic stressors, notably climate change and pollution by pharmaceuticals. Global warming is predicted to raise water temperatures by 2–5 °C by the end of the century. As ectotherms, fish are particularly vulnerable due to limited thermal tolerance and temperature-dependent physiology. Pharmaceuticals are introduced into aquatic systems at concentrations ranging from ng·L⁻¹ to µg·L⁻¹, including widely prescribed classes such as antibiotics, hormones, analgesics, antifungals, and neuropsychiatric drugs. This narrative review synthesizes experimental evidence on the interactive effects of warming and pharmaceutical exposure in fish. Thirty-nine peer-reviewed studies published since 2005 were analyzed. The findings indicate that higher temperatures often exacerbate pharmaceutical-induced toxicity, altering oxidative stress, metabolism, reproduction, and behavior. Antibiotic-focused studies showed temperature-dependent acceleration of absorption, distribution, metabolism, and excretion, with shorter half-lives and reduced tissue persistence at higher temperatures. Estrogenic hormones and antifungals have been shown to interact with thermal regimes, disrupting reproductive physiology and skewing sex ratios, particularly in species exhibiting temperature-dependent sex determination. Neuropsychiatric drugs exhibited altered uptake and metabolism under warming conditions, resulting in increased brain bioaccumulation and behavioral alterations affecting ecological fitness. Analgesics and anti-inflammatories remain understudied despite their widespread use, with evidence suggesting synergistic effects on oxidative stress at elevated temperatures. Significant research gaps persist regarding chronic exposures, early developmental stages, ecologically relevant temperature scenarios, and underrepresented or absent drug classes, such as hypolipidemic drugs. Ultimately, broader and integrated approaches are needed to better understand and predict the ecological risks of pharmaceutical pollution in a warming world. Full article

The estuaries of the Mississippi River Delta are among the most productive coastal ecosystems in the world and have attracted human fishing communities for centuries. Beginning in the early 20th century, the oil and gas industry also emerged as a powerful economic force in exploiting coastal fossil fuel deposits. This paper reviews the complex history of the oil and gas industry in Southeast Louisiana, including its relationships with political corruption, inequality, pollution, and environmental catastrophe; and also its role in supporting coastal fishing communities with complementary economic opportunities. In the 21st century, a series of disasters—above all Hurricane Katrina in 2005 and the B.P. oil spill in 2010—drew attention to the risks inherent to the region, as well as its crucial role in buffering the impacts of tropical storms for inland urban communities. This paper examines the evolution of fisheries regulations and their consequences of small-scale fishers, focusing especially on the banning of gill net use in 1990s. By combining historical information with ethnographic interviews and participant observation, this paper examines the complex political–economic forces involved in shifting regulatory frameworks and policies, and it shows their negative consequences for fishing communities facing an existentially threatening combination of coastal erosion, fisheries declines, and various macroeconomic headwinds. This paper argues that resilient coastal communities are crucial to combating the environmental problems facing coastal regions and that rethinking fisheries regulations may be a dynamic tool in enhancing community resilience. Full article