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The Heilongjiang River is one of the largest rivers in the cool temperate zone and has an abundant fish source. To date, the microbiota community in water samples and fish guts from the Heilongjiang River is still unclear. In the present study, water samples and fish guts were collected from four locations of the Heilongjiang River during both the dry season and the wet season to analyze the spatio-temporal dynamics of microbiota communities in the water environment and fish guts through 16s ribosome RNA sequencing. The water qualities showed seasonal changes in which the pH value, dissolved oxygen, and total dissolved solids were generally higher during the dry season, and the water temperature was higher during the wet season. RDA indicated that higher pH values, dissolved oxygen, and total dissolved solids promoted the formation of microbiota communities in the water samples of the dry season, while higher water temperature positively regulated the formation of microbiota communities in the water samples of the wet season. LEFSe identified five biomarkers with the most abundant difference at the genus level, of which TM7a was upregulated in the water samples of the dry season, and SM1A02, Rheinheimera, Gemmatimonas, and Vogesella were upregulated in the water samples of the wet season. Pearson analysis revealed that higher pH values and dissolved oxygen positively regulated the formation of TM7a and negatively regulated the formation of SM1A02, Rheinheimera, Gemmatimonas, and Vogesella (p < 0.05), while higher water temperature had the opposite regulatory roles in the formation of these biomarkers. The relative abundance of microbiota diversity in fish guts varies greatly between different fish species, even if the fishes were collected from the same water source, indicating that dietary habits and fish species may be key factors, affecting the formation and construction of microbiome community in fish gut. P. glenii, P. lagowskii, G. cynocephalus, and L. waleckii were the main fish resources, which were collected and identified from at least six sample points. RDA indicated that the microbiota in the water environment regulated the formation of microbiota community in the guts of G. cynocephalus and L. waleckii and had limited regulated effects on P. glenii and P. lagowskii. The present study identified the regulatory effects of water qualities on the formation of microbiota communities in the water samples and fish guts, providing valuable evidence for the protection of fish resources in the Heilongjiang River. [ABSTRACT FROM AUTHOR]

Albino-Martínez, O. and Rosales-Casián, J.A., 2024. Ecology of economically important fish at a temperate Pacific Island of Baja California, Mexico. Journal of Coastal Research, 40(5), 919–928. Charlotte (North Carolina), ISSN 0749-0208. Economically important fish were caught in rocky reefs around Isla San Martin, Baja California, Mexico to determine the composition and spatio-temporal variations, their possible relationship with temperature, upwelling and depth, and the size structure of the most abundant species. Five seasonal surveys were carried out using traps and hook-and-line at four different sites from June 2021 to May 2022. A total of 595 fish individuals (417 kg) were caught, comprising of 23 species from 10 families, and the Sebastidae family contributed the largest number of 12 species. The most abundant fish species were Caulolatilus princeps, Paralabrax clathratus, Semicossyphus pulcher, Paralabrax nebulifer, Sebastes auriculatus, S. umbrosus, and S. rastrelliger that contributed 90.2% of the total abundance. C. princeps contributed 60.8% of the abundance and 60.2% of the biomass. The first three fish species were the most important in terms of relative abundance and frequency of occurrence. The catch means (abundance and biomass) per trap or angler did not change over time; however, between sites, the average fish catch per trap (abundance and biomass) was significantly different, which presented a positive and significant relationship with depth, only. The fish richness (number of species) varied between nine (fall 2021) and 14 species in spring 2021 and 2022. The highest diversity of fish species (H' = 1.9) occurred in summer (C. princeps 41.1% abundance), and the lowest diversity (H' = 1.0) during fall (C. princeps 74.1%. abundance). Among fishing sites, the greatest diversity occurred close to Isla San Martín (El Bufeo, H' = 2.1), and the lowest diversity in the deeper sites far from the island (Bajo 6, H' = 1.0). Caulolatilus princeps presented 100% frequency of occurrence, while Chromis punctipinnis, Halichoeres semicinctus, Medialuna californiensis, and Sebastes serranoides occurred with the lowest value (4.5% each). [ABSTRACT FROM AUTHOR]

The practice of hybridization is carried out globally in fish farms. Here, we present the first record of the parasitic fauna of hybrids among genus Colossoma and Piaractus in natural environments. We identified a total of 48 hybrids, nine F1 hybrids (nuclear DNA from both species present in the cross) and 38 advanced hybrids (nuclear DNA from one species), both from crosses between Piaractus brachypomus and Piaractus mesopotamicus, and one F1 "tambacu" corresponding to cross between Colossoma macropomum and Piaractus mesopotamicus. This is the first record of Anacanthorus penilabiatus, Anacanthorus toledoensis, Mymarothecium viatorum, Mymarothecium ianwhittington, Haementeria sp., Dadaytrema oxycephala, Rondonia rondoni, and Echinorhynchus gomesi parasitizing hybrids collected in a natural environment. With this, we expand knowledge about the diversity of fish and parasites in the upper Paraná River and warn about the risk that fish escapes can cause in the basin. [ABSTRACT FROM AUTHOR]

A 21-day continuous monitoring of a highly tridimensional forest of the black coral Antipathella subpinnata (Ellis and Solander 1786) was carried out in the NW Mediterranean Sea at 63 m depth using an autonomous lander to investigate the diel short-term dynamics of the vagile fauna associated to the forest. The survey allowed to assess several aspects of the forest attractiveness and its use, especially by the ichthyofauna, including (i) the diversity and shifts of the fish community inhabiting three layers of the environment (seafloor, canopy, water column) between four light phases (dawn, day, dusk, night), (ii) the diel rhythm in forest use of the red swallowtail perch Anthias anthias (Linnaeus 1758) and its sleeping behaviour in terms of fidelity towards resting sites, duration of rests, and awakenings triggers, and, finally, (iii) the influence of biotic and abiotic variables on the fish behaviour. Considering that, so far, only spot censuses have been carried out in these habitats, this study provides a dynamic approach to the study of biodiversity in temperate mesophotic coral forests and offers an insight into the functioning of these complex and vulnerable ecosystems. [ABSTRACT FROM AUTHOR]

Aim: Temperature is regarded as an important driver of broad‐scale biodiversity patterns. However, less is known of the role of dispersal in shaping broad‐scale species and trait distributions, particularly given that species had to disperse out of glacial refugia after the Last Glacial Maximum (LGM). Here, we used a unique dataset describing the distributions of freshwater fauna combined with trait information to evaluate biodiversity relationships to distance to glacial refugia and temperature. Location: Twenty‐five biogeographical regions across Europe. Time Period: Data from species occurrence were gathered in 1978. Major Taxa Studied: A total of 2816 freshwater invertebrate species and 230 freshwater fish species. Methods: Using the occurrence of invertebrate and fish species in the biogeographical regions, and publicly available trait information, we analysed patterns in diversity indices (i.e. species richness, trait richness and trait redundancy), trait distribution and species and trait β‐diversity, and their relationship to distance to known glacial refugia and regional temperature. Results: We show that distributions of European invertebrate and fish species and traits are primarily explained by distance to refugia and its covarying effect with temperature (i.e. refugia tend to be warmer). Specifically, species and trait richness were higher in regions proximate to refugia and lower in distant regions. Additionally, communities in colder and distant regions exhibited reduced niche dimensions and slower life histories, suggesting increased vulnerability to environmental change. Main Conclusions: Species more distant from their refugia were characterized by higher dispersal capacities. Accordingly, since the LGM, only a subset of species was able to colonize distant regions, while many species have spatial ranges constrained by their dispersal capacity, increasing their potential for extinction under ongoing climate change. Therefore, additional conservation measures considering species' dispersal capacities are required. [ABSTRACT FROM AUTHOR]

Aim: Substantial progress has been made to map biodiversity and its drivers across the planet at multiple scales, yet studies that quantify the evolutionary processes that underpin this biodiversity, and test their drivers at multiple scales, are comparatively rare. Studying most fish species, we quantify rates of body size evolution to test the role of fundamental salinity habitats in shaping rates of evolution at multiple scales. We also determine how four additional factors shape evolutionary rates. Location: Global. Time Period: Extant species. Major Taxa Studied: Actinopterygii. Methods: In up to 1710 comparisons studying over 27,000 species, we compare rates of body size evolution among five salinity habits using 13 metrics. The comparisons span a molecular tree, 100 supertrees, and 10 scales of observation to test for robust patterns and reveal how patterns change with scale. Then, three approaches assess the role of three non‐salinity factors on rates, and an alternative habitat scheme tests if lakes influence evolutionary rates. Results: Rates of size evolution rarely differ consistently between salinity habitats; rate patterns are highly clade‐ and scale dependent. One exception is freshwater‐brackish fishes, which possess among the highest size rates of any salinity, showing higher rates than euryhaline fishes in most groupings studied at most scales, and versus marine, freshwater and marine–brackish habitats at numerous scales. Additionally, species richness had the greatest potential to predict phenotypic rates, followed by branch duration, then absolute values of body size. Lacustrine environments were consistently associated with high rates of size evolution. Main Conclusions: We reveal the rate patterns that underpin global body size diversity for fishes, identifying factors that play a limited role in shaping rates of size evolution, such as salinity, and those such as species richness, age and lake environments that consistently shape evolutionary rates across half of vertebrate diversity. [ABSTRACT FROM AUTHOR]

The present study was conducted on August 2020 to study the diversity of fishes in Dikhu River under Longleng District, Nagaland. The fish species were collected and for identification systematic list and while nomenclature was after FishBase (http//www.fishbase.org). A total of 11 species of fishes, representing 5 orders (Cypriniformes, Siluriformes, Perciformes, Synbranchiformes and Anguilliformes), 9 families (Cyprinidae, Balitoridae, Sisoridae, Siluridae, Heteopneustidae, Bagridae, Mastacembelidae, Anguillidae, Channidae) and 11 genera were collected from the Dikhu River, Longleng District. Among the fish species collected from the river, the order Cypriniformes composed of 37% was the most dominant, followed by Siluriformes composed of 27%, Perciformes composed of 18% and the remaining order Synbranchiformes, Anguilliformes composed of 9% and the number of individual species was highest from the order Cyprinformes (Devio aequipnatus sp.). The short term study does not cover up all the fish species that are found in the river. Therefore, the further study on the diversity of fish can be done. [ABSTRACT FROM AUTHOR]

Diet has been identified as a major driver of reef fish lineage diversification, producing one of the most speciose vertebrate assemblages today. Yet, there is minimal understanding of how, when and why diet itself has evolved. To address this, we used a comprehensive gut content dataset, alongside a recently developed phylogenetic comparative method to assess multivariate prey use across a diverse animal assemblage, coral reef fishes. Specifically, we investigated the diversification, transitions and phylogenetic conservatism of fish diets through evolutionary time. We found two major pulses of diet diversification: one at the end-Cretaceous and one during the Eocene, suggesting that the Cretaceous–Palaeogene mass extinction probably provided the initial ecological landscape for fish diets to diversify. The birth of modern families during the Eocene then provided the foundation for a second wave of dietary expansion. Together, our findings showcase the role of extinction rebound events in shaping the dietary diversity of fishes on present-day coral reefs. [ABSTRACT FROM AUTHOR]

Shifts in environmental conditions can impose strong selection for adaptive traits. During the Cenozoic era, as the oceans cooled, many marine teleost fish species were at risk of freezing. This led to the independent emergence of distinct ice‐binding antifreeze proteins (AFPs). The report in this issue by Graham and Davies reveals the development of AFP genes in shorthorn and longhorn sculpin from a copy of the lunapark gene. The predicted sculpin AFP sequences are unrelated to that of lunapark; the coding sequences for the AFPs appear to have arisen from small portions of the lunapark gene by codon frameshifting along with a series of mutations. [ABSTRACT FROM AUTHOR]

Simple Summary: The construction of dams in Mabiehe River has significantly impacted fish diversity, resulting in reduced species richness and diversity within dammed sections compared to undammed segments of the river. The environmental DNA (eDNA) technique is effective in assessing fish diversity in the challenging environment of canyon rivers. The successful detection of a variety of species, including both protected and exotic ones, highlights the robustness of eDNA as a comprehensive monitoring tool. Investigating fish diversity in canyon rivers through conventional fish surveys is challenging due to precipitous conditions, including steep slopes, rapid water flow, and complex habitats. Additionally, intensive construction of dams has further complicated the understanding of contemporary fish diversity in these rivers. In this study, we used the environmental DNA (eDNA) technique to assess fish diversity and examine the effects of dams on fish diversity in the Mabiehe River, a canyon river in the upper reaches of the Pearl River drainage. Water samples from 15 sampling sites were collected, yielding 9,356,148 valid sequences. Utilizing the NCBI public database, a total of 60 freshwater fish species were identified, with Carassius auratus, Cyprinus carpio, and Pelteobagrus fulvidraco being the most dominant species in the Mabiehe River. We also detected one nationally protected fish species, three provincially protected fish species, and six exotic species in this river. Furthermore, eDNA analyses demonstrated that the lotic river sections harbor more species and greater diversity than dammed sections, suggesting that dams might exert significant impacts on local fish diversity. Overall, this study supports the effectiveness of the eDNA technique as a complementary tool to traditional field surveys for monitoring fish biodiversity in canyon rivers. [ABSTRACT FROM AUTHOR]

Simple Summary: Ecological fishery management is one of the predominant approaches to lake ecological management in China; it involves the stocking of filter-feeding fish species to mitigate algal blooms. This strategy not only enhances water quality but also yields ecological benefits by fostering the growth of fish populations, thereby offering both ecological and economic advantages. Nonetheless, there is a scarcity of works in the literature addressing the effects on fish community dynamics and diversity in lakes subsequent to the cessation of ecological fishing practices. This study focuses on the initial changes observed in fish community composition and diversity following the cessation of an ecological fishery project in Qilu Lake, an eutrophic shallow lake situated in China. Ecological fishery projects aim to improve the water quality of eutrophication lakes by stocking filter-feeding fish species that feed on algae. The findings indicate a significant decline in the number of fish species, average individual size, and species diversity index following the cessation of fisheries-related activities (including fish stocking and fishing activities) due to the termination of the ecological fishery project in the lake. To preserve fish biodiversity and enhance water quality in Qilu Lake, it is recommended that policies be implemented to sustain the implementation of ecological fisheries projects, restore habitats for native fish species, and regulate the proliferation of small fish populations. The Qilu Lake is an eutrophic shallow lake located in Yunnan Province, China. An ecological fishery project was initiated in the lake from 2011 to 2021 to introduce filter-feeding fish species that feed on algae, with the aim of improving water quality. In January 2022, when the ecological fishery project expired, all fisheries-related activities (including fish stocking and fishing activities) ceased in the lake. To comprehensively evaluate the initial alterations in fish community structure and diversity resulting from the fishing cessation in the Qilu Lake, the present study conducted field surveys within the one year before the fishing cessation (referred to as BFC) and the one year after the fishing cessation (referred to as AFC). A total of twenty-one fish species were collected, including four native species. Four species were recorded in the lake for the first time, including Pelteobagrus fulvidraco, Pelteobagrus vachelli, Paramisgurnus dabryanus, and Hyporhamphus intermedius. The number of fish species decreased from 21 to 13 following the fishing cessation. The fishes collected in both BFC and AFC are mainly omnivorous-feeding and of bottom-dwelling habits. The mean size of the fishes in the AFC sample shows a significant decrease compared to those in BFC. After the fishing cessation, the Shannon–Wiener diversity index and Margalef richness index of the fish slightly declined. The fish community structure of the Qilu Lake exhibits a high degree of similarity to adjacent lakes in central Yunnan. Our study demonstrates a significant shift in the fish community of the Qilu Lake following the fishing cessation, one which may adversely impact the stability of the lake ecosystem. To enhance fish species diversity in the Qilu Lake, it is recommended that policies be implemented to promote the ecological fishery project and improve habitat restoration for native fish species, while also regulating fish community structure. [ABSTRACT FROM AUTHOR]

Aim Location Methods Results Conclusions Surf zones are crucial nursery habitats for the early life stages of fish species associated with typical coastal ecosystems. However, little is known about the temporal patterns and drivers of fish assemblages in tropical surf zones. This study aimed to assess the (1) main changes in fish community structure throughout 1 year, (2) seasonal dynamic patterns in fish assemblages, and (3) key factors influencing fish assemblages in the tropical surf zones.Gaolong Bay, Wenchang City, Hainan Island, China.Fish sampling was conducted monthly from June 2021 to May 2022 using a beach seine net. Fish species were identified using both morphological and molecular analyses. Kruskal–Wallis test, analysis of similarity, non‐metric multidimensional scaling analysis, and similarity percentage analysis were used to investigate the temporal fish assemblage patterns. Generalised additive models and canonical correspondence analysis were used to assess how environmental variables influence fish assemblages.We identified 83 fish species, which were grouped into three ecotypes based on their primary habitat: coral reef‐seagrass‐associated species (CS) (35), mangrove‐estuarine‐associated species (ME) (30), and common coastal‐estuarine‐associated species (CE) (18). Most captured individuals were juveniles, and fish abundance and diversity were highest in May. Most CS species were abundant between March and May. ME and most CE species were dominant from June to August, and Mugilidae (CE) was abundant between October and February. Furthermore, surf fish assemblages were substantially influenced by tidal level, water temperature, conductivity, pH, turbidity, and dissolved oxygen.Juvenile fish were abundant in May and fish species with three ecotypes alternate in the surf zones throughout the year. Counter to much current thinking, March maybe the spawn peak of most fish species in the studied area, and we suggest that the fishing ban period could start from March instead of May in the inshore areas of Hainan Island. [ABSTRACT FROM AUTHOR]

The development of fast, cost-effective, non-invasive, and efficient sampling alternatives, such as environmental DNA (eDNA), is crucial for understanding the changes in species biodiversity and distributions worldwide, particularly for low abundance, cryptic, and threatened species. This study utilized environmental eDNA to analyze the variety of aquatic, semi-aquatic, and terrestrial vertebrates in the Colombian Amazon and Orinoco basins. The study focused on four main subregions: Bojonawi Natural Reserve and adjacent areas (Vichada Department), Sierra de la Macarena National Park and Tillavá(Meta Department), Puerto Nariño and adjacent areas (Amazonas Department), and the Municipality of Solano (CaquetáDepartment). A total of 709 operational taxonomic units (OTUs) were identified across all sampling locations. The Orinoco River had the highest number of fish genera (68), while the Guayabero River had the highest number of tetrapod genera (13). New taxonomic records were found for all locations, with the highest number of previously undetected fish diversity being found in the Bita, Orinoco, and Tillavárivers, compared to traditional surveys. Likewise, the study identified two fish species, four mammal species, and one reptile species as vulnerable. Additionally, four mammal species were identified as endangered, including the giant otter (Pteronura brasiliensis), two subspecies of the Amazon River dolphin (Inia geoffrensis geoffrensis and Inia geoffrensis humboldtiana), and the tucuxi (Sotalia fluviatilis). Standardizing the methodology and improving current DNA sequence databases for the Neotropics is essential to develop future eDNA studies and enhance our understanding of the region's diversity. [ABSTRACT FROM AUTHOR]

Since the last century, the aquatic ecosystems of Tierra del Fuego have been impacted by the introduction of exotic species, among which the North American beaver Castor canadensis and salmonids stand out for their dispersion and abundance. This study is part of the project Strengthening Governance for the Protection of Biodiversity Through the Formulation and Implementation of the National Strategy on Invasive Alien Species, for the eradication of C. canadensis from the Isla Grande de Tierra del Fuego (IGTdF). This work aimed to evaluate the effect of beaver plantation removal on different aspects of the ichthyofauna of the IGTdF. Ichthyological sampling was carried out before and after the beaver ponds in six sites spread across the island. Three species of salmonids (Salmo trutta, Oncorhynchus mykiss and Salvelinus fontinalis) were captured, and an average increase of 43% in their abundance, changes in their diet, and differences in their energy density (higher or lower depending on the species) was observed after the removal of the beaver ponds. No native fish species were recorded before or after the removal of the beaver pond. The results suggest that the beaver ponds impact positively salmonid populations. [ABSTRACT FROM AUTHOR]

Simple Summary: In environments characterized by small-scale islands, terrestrial inputs, like freshwater discharges, can significantly impact fish communities compared to ocean currents. While the influence of river discharge on marine biodiversity is well documented, the effects of submarine groundwater discharge on nearshore fish communities are less understood. Here, our results provide evidence that submarine groundwater discharge crucially influences coastal fish diversity by altering salinity and nutrient supply. This study also showed that fish community composition varies considerably over a small spatial scale, reflecting habitat partitioning on the target island. Submarine groundwater discharge (SGD) has recently been recognized as an influential factor in coastal ecosystems; however, little research has been conducted on its effects on coastal fish diversity. To investigate the relationship between SGD and fish diversity, we conducted a survey at the coastal island scale using the environmental DNA (eDNA) method. Our findings indicate that fish species richness and functional richness peak at stations with high SGD. Environmental variables, such as salinity, dissolved inorganic nitrogen (DIN) concentration, and SGD, significantly influence fish diversity. Carnivore fish richness was negatively correlated with salinity, while planktivore fish richness was positively correlated. Additionally, SGD and DIN concentrations were found to be crucial in shaping omnivorous and pelagic communities, respectively. This study highlights the role of SGD in enhancing nutrient conditions favorable for diverse fish communities and demonstrates the effectiveness of eDNA metabarcoding for rapid marine biodiversity assessment. These findings provide valuable insights for coastal ecosystem monitoring and management. [ABSTRACT FROM AUTHOR]

Dams are one of the greatest threats to freshwater biodiversity and efforts to remove dams to restore riverine systems are increasing. However, dam‐removal studies have primarily focused on taxonomic responses to large dam removals with little work on the functional trait responses of fish to small‐dam removals; such a focus limits the application of results in regions with different taxonomic compositions.We explored taxonomic and functional trait responses of fish assemblages to two small‐dam removals over 10 years using a Multiple Before After Control Impact design at a dammed and an undammed river. Eight life‐history traits were used to calculate functional diversity (RaoQ) and determine the position of each fish species within a multivariate life‐history space relative to three life‐history strategy endpoints: opportunistic, periodic, and equilibrium. The distance of each species relative to these endpoints was used to calculate community weighted means (CWM), allowing us to examine the shift in life‐history strategy of a given assemblage after dam removal. Based on life‐history theory, we predicted a decrease in the CWM of equilibrium strategists and an increase in the CWM opportunistic strategists after dam removal.For the dammed river, we observed changes in assemblage structure at both the control and impact sites driven primarily by shifts from a lentic to lotic assemblage, with the most apparent change occurring in the formerly impounded sites. These changes tended to occur within 1 year, suggesting rapid colonization by lotic species after habitat change. By contrast, no change in assemblage structure was found for the undammed river, suggesting that dam removal was the primary driver of the shifts in assemblage structure observed in the dammed river. We found no change in the CWM of periodic strategists or RaoQ of all life‐history traits at any site after dam removal.Based on CWM, life‐history strategies shifted in response to dam removal at impounded sites where equilibrium strategists decreased and opportunistic strategists tended to increase after the impounded sites changed from a stable lentic environment to an unstable lotic environment, supporting predictions made by life‐history theory.Our results suggest that small‐dam removal may provide ecological benefits by restoring fish assemblages to a more natural riverine state and reversing the negative effects of dam construction on the ecosystem. We demonstrate that combining both trait‐based and taxonomic approaches can improve our ecological understanding of the impacts of dam removal on fish assemblages and provide relevant data for local management. [ABSTRACT FROM AUTHOR]

Anthropogenic land use has caused a major crisis to the biodiversity of stream fishes in recent decades, especially with regard to biotic homogenisation. Understanding the response of stream fishes to anthropogenic land use will help to promptly implement effective conservation measures. In this study, we investigated the effects of agriculture on fish diversity in streams in the Wannan Mountains, China. We predicted that agriculture would influence fish diversity by affecting local habitat conditions. The results showed that habitat conditions (e.g. water temperature, water width, water depth) differed significantly between disturbed and reference sites. The disturbed sites had high species richness due to the addition of translocated species outpacing the loss of endemic species. Moreover, fish assemblages showed taxonomic differentiation accompanied by functional homogenisation, which mainly resulted from the addition of translocated species with redundant functional traits. However, the emergence of homogenisation shows a time delay. The biotic differentiation of fish assemblages in agroecosystems is temporary in the Wannan Mountains, and homogenisation may eventually develop as stress intensifies. Thus, it is urgent and necessary to take effective conservation measures to delay or prevent fish assemblages from worsening in agroecosystems before homogenisation develops. [ABSTRACT FROM AUTHOR]

Increasing human pressures threaten fish diversity, with potentially severe but unknown consequences for the functioning of riverine food webs.Using a 17‐year dataset from multi‐trophic fish communities, we investigated the long‐term effects of human pressure on the diversity and food web functioning. Combining metabolic scaling and ecological network principles, we calculate the annual energy fluxes through trophic compartments (top‐carnivore, mesocarnivore, detritivore and omnivore). Energy fluxes link trophic compartments, and thus represents food web functions such as carnivory, omnivory, herbivory and detritivory.Species richness across all trophic compartments was positively associated with energy flux. However, species richness decreased over time, as did the energy flux at the whole‐network level, which was reduced by 75%. Human pressure negatively affected both species richness and energy flux. Moreover, the negative impacts of human pressure on energy flux have intensified over time.Our results illustrate how human pressure can reduce diversity and erode the energy flux through food webs, with negative implications for the ecosystem functioning. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

The Ib River is an important tributary of the Mahanadi River. The aim of the present study was to establish a reliable barcoding reference database for fish in Ib River. A total of 134 specimens, belonging to 42 species within 32 genera, 18 families, and 11 orders, were subjected to PCR amplification of the target region of mitochondrial genome and sequenced. The average length of the 134 barcodes was 648 bp. The average K2P distances within species, genera, and families were 0.13, 9.94, and 16.79%, respectively. The average interspecific distance was approximately 76.46 times higher than the mean intraspecific distance. The Barcode Index Number (BIN) discordance report showed that 134 specimens represented 42 BINs, of which 13 were singletons, 29 were taxonomically concordant while no species taxonomically discordant in our dataset. The barcode gap analysis demonstrated that 100% of the fish species examined could be discriminated by DNA barcoding. These results provide new insights into fish diversity in the Ib River and can provide a basis for the development of further studies on fish fauna. [ABSTRACT FROM AUTHOR]

The combination of the physical structural heterogeneity of the environment, oceanographic characteristics, and the benthic assemblage composition structures the habitat, consequently shaping the associated diversity of fish. Understanding the spatial variability of fish assemblages and how it relates to environmental factors is essential to identify potential variables that determine spatial patterns and predict impacts on fish assemblage metrics, thus providing valuable information for management. Here, we investigated reef fish micro-scale spatial distribution around Alcatrazes Island in the subtropical region of the Southwest Atlantic, Brazil. Multivariate Regression Trees were fitted to explore the effects of structural heterogeneity, wave power, depth, water temperature, and benthic cover on the structure of reef fish assemblages, addressing composition, richness, density, biomass, trophic groups, mobility, and conservation status. Our results suggest that depth, turf, and coral cover were the main predictors of fish assemblages in rocky reefs at Alcatrazes Island, revealing five distinct fish assemblages with different habitat preferences. These results provide additional insights into the relationship between reef fishes and their environment, providing empirical evidence for decision-makers to implement spatially based management policies, especially to prioritize zones for conservation along the island. [ABSTRACT FROM AUTHOR]

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The identification of multiple facets of biodiversity (e.g., phylogenetic and functional) can help to understand how evolutionary and ecological mechanisms shape the assembly of biological communities. Here, we employed multiple regressions and variance partitions to investigate the effects of environmental conditions, connectivity and space on aspects of the functional and phylogenetic facets of fish fauna in tropical headwater streams of the Xingu River basin, in Eastern Amazonia. We found that the functional and phylogenetic diversities of fish communities are related to local environmental conditions and stream connectivity in the drainage network, with marked differences occurring between the rainy and dry periods. Furthermore, we discovered that functional uniqueness was influenced mainly by environmental factors, whereas phylogenetic uniqueness had a more complex relationship with the influence of local environmental factors and connectivity. Our findings indicate that the fish assemblages of small headwater streams of the Xingu River basin share a close phylogenetic history. This is probably because of the climatic and environmental stability experienced by Amazonian ichthyofauna over evolutionary time. Our findings emphasise the role of niche‐based processes in shaping the unique functional composition of fish assemblages in headwater streams, and highlight the importance of environmental heterogeneity in maintaining the ecological integrity of these freshwater ecosystems. [ABSTRACT FROM AUTHOR]

Marine sponges have recently emerged as efficient natural environmental DNA (eDNA) samplers. The ability of sponges to accumulate eDNA provides an exciting opportunity to reconstruct contemporary communities and ecosystems with high temporal and spatial precision. However, the use of historical eDNA, trapped within the vast number of specimens stored in scientific collections, opens up the opportunity to begin to reconstruct the communities and ecosystems of the past. Here, we define the term ‘heDNA’ to denote the historical environmental DNA that can be obtained from the recent past with high spatial and temporal accuracy. Using a variety of Antarctic sponge specimens stored in an extensive marine invertebrate collection, we were able to recover information on Antarctic fish biodiversity from specimens up to 20 years old. We successfully recovered 64 fish heDNA signals from 27 sponge specimens. Alpha diversity measures did not differ among preservation methods, but sponges stored frozen had a significantly different fish community composition compared to those stored dry or in ethanol. Our results show that we were consistently and reliably able to extract the heDNA trapped within marine sponge specimens, thereby enabling the reconstruction and investigation of communities and ecosystems of the recent past with a spatial and temporal resolution previously unattainable. Future research into heDNA extraction from other preservation methods, as well as the impact of specimen age and collection method, will strengthen and expand the opportunities for this novel resource to access new knowledge on ecological change during the last century. [ABSTRACT FROM AUTHOR]

Nepal holds a high ichthyofaunal diversity, nevertheless, the molecular study of Nepalese fish is still in its early stages. The first record of a cyprinid fish species the Garra kempi Hora, 1921 for Nepal was reported from eastern Nepal's Lohandra River. Both morphology and molecular data affirmed the existence of G. kempi in Nepal's aquatic system. This species was previously reported from China (Tibet) and northern India. The maximum likelihood phylogenetic analysis and pairwise genetic distance based on Kimura 2 parameters using cytochrome oxidase subunit 1 (COI) segment sequences (665 bp) also confirmed the identity of the species as G. kempi. The COI sequences of specimens from Nepal formed a monophyletic clade with the sequence of G. kempi from northeastern India and the two contained a pairwise genetic distance of 1.8% only. The new record of G. kempi from Nepal warrants a detailed ichthyofaunal survey for documenting the fish diversity in Nepal. [ABSTRACT FROM AUTHOR]

Despite the critical role of mitochondrial genomes (mitogenomes) in species identification and evolutionary studies in the genus Parupeneus, current resources are inadequate, given the species richness. Although previous studies have suggested a complex evolutionary history, the detailed mitogenomic variations and their implications remain largely unexplored. Therefore, we sequenced and assembled the mitogenomes of P. barberinoides, P. barberinus, P. biaculeatus, P. crassilabris, P. cyclostomus, P. heptacanthus, P. multifasciatus, and P. chrysopleuron, to enrich the molecular data and provide novel insights into the genetic diversity, evolutionary dynamics and phylogenetics of the family Mullidae. Our analysis revealed a novel gene rearrangement in P. chrysopleuron, Cytb-T-P-CR-Q-I-F-12S-V-16S-ND1-M-ND2, which differed from the conventional sequence of Cytb-TP-CR-F-12S-V-16S-ND1-I-Q-M-ND2 observed in other species. In the novel rearrangement, four non-coding regions are inserted between ND1 and M, Q and I, I and yM (tRNA-Met pseudogene), yM and F. We assume that two tandem duplication/random loss events occur in the CR and IQM, making the entire sequence longer than that in other Parupeneus species. The phylogenetic results indicated that Mullidae formed a sister group relationship with the family Dactylopteridae, contradicting previous studies that identified a sister group relationship between Mullidae and Callionymoidei. The genera Parupeneus and Mullus formed a sister group, and discrepancies were found in the topological structure of the interspecies relationships within the genus Parupeneus compared with those reported by previous studies. Through combined phylogenetic and mitochondrial structural analysis, we found that phylogenetic topology is closely related to mitochondrial structural abnormalities. This study not only expands the mitogenomic dataset available for Mullidae but also underscores the importance of mitochondrial DNA studies in resolving taxonomic ambiguities and understanding the evolutionary history of marine fishes. Our study contributes to the ongoing research on marine fish taxonomy, mitogenomics, and evolutionary biology by providing new insights into the genetic diversity of marine ecosystems. [ABSTRACT FROM AUTHOR]

Fish telemetry studies now routinely collect positional and depth data, yet analytical approaches that integrate three‐dimensional data are limited. Here we apply the potential path volume (PPV) model, a method previously developed to estimate habitat volume based on rates of avian movement, to free‐swimming fish. Using a telemetry dataset of white sucker (Catastomus commersonii) from Turkey Lake (Ontario, Canada), we evaluated the effects of the number of spatial positions and different methods of selecting swim speed (vswim), a key parameter for PPV models, on habitat volume estimates. We subsequently compared habitat volume estimates and habitat overlap among white sucker pairs from the PPV models to those calculated using kernel utilization distribution‐based approaches. The number of spatial positions in the PPV model had a significant effect on habitat volume estimates, whereas the magnitude of the vswim parameter or its specificity (constant value vs. fish‐season specific parameter values) did not affect habitat volume estimates. The PPV method resulted in larger habitat volume estimates and greater habitat overlap estimates among fish pairs relative to those obtained from a three‐dimensional kernel utilization distribution method. The PPV model is a useful analytical tool that, by incorporating potential animal movement into habitat use evaluations, can help answer key ecological questions and provide insight into fish space use in a wide range of conservation and management applications. [ABSTRACT FROM AUTHOR]

To understand the fish community structure characteristics and changes in Poyang Lake after the Yangtze River fishing ban in 2021, seven sampling stations were established, namely in Hukou, Lushan, Duchang, Yongxiu, Nanjishan, Ruihong, and Poyang, for fishery resource surveys between 2020 and 2021. The results showed that 93 fish species were identified, belonging to 11 orders, 20 families, and 61 genera, which was an increase of 4.5% from before the fishing ban. Of these, 52 Cyprinidae species were identified, comprising the highest proportion (55.91%). Four invasive alien species (hybrid sturgeon, Cirrhina mrigala, Piaractus brachypomus, and Mugil cephalus) were identified, and the number of alien species in Poyang Lake was higher than before the fishing ban. Carnivorous and mid-lower-level fish showed a significant increase, accounting for 47.31% and 38.71% of the total species, respectively. Compared with the Yangtze River before the fishing ban, the body length and body weight of the main economic fish in Poyang Lake increased by 6.10–61.26% and by 15.14–291.57%, respectively. In terms of age structure, the proportion of major economically important fish aged 1 or 2 years decreased significantly, while the proportion of older fish increased substantially. There was little difference in the diversity of fish communities at different stations in Poyang Lake. In terms of biodiversity, the Shannon–Wiener index ranged from 2.158 to 2.909, with Poyang having the highest value and Nanjishan the lowest. Margalef's index ranged from 4.265 to 6.459, with Lushan having the highest value and Nanjishan the lowest. Pielou's index ranged from 0.617 to 0.822, with Duchang having the highest value and Nanjishan the lowest. Hence, the Yangtze river fishing ban has played an important and positive role in the restoration of fishery resources in Poyang Lake. However, long-term tracking and monitoring are needed to provide information to comprehensively evaluate the ecological impact of the Poyang Lake fishing ban. [ABSTRACT FROM AUTHOR]

Climate change has led to significant fluctuations in marine ecosystems. As a component of the food web, the trophic diversity and spatiotemporal changes of fish communities are crucial for understanding ecosystems. In recent years, stable isotope analysis has been increasingly used as a comprehensive tool for quantitative assessment of trophic diversity to explore spatiotemporal variations in fish community diversity. This study is based on carbon (δ 13C) and nitrogen (δ 15N) stable isotope analysis using different biomass-weighted isotope diversity indices, including isotopic divergence index (IDiv), isotopic dispersion index (IDis), isotopic evenness index (IEve), and isotopic uniqueness index (IUni). The overall results indicate that IDis, IEve, and IUni values of fish communities were relatively low, while IDiv was relatively high in the Haizhou Bay ecosystem. IDiv, IDis, IEve, and IUni were lower in autumn than in spring; IDiv and IDis were relatively higher in offshore waters, while IEve and IUni were relatively higher in inshore waters. The changes in species composition and intensive pelagic–benthic coupling in Haizhou Bay may lead to significant spatiotemporal variations in the trophic diversity of fish communities in the area. These findings highlight the importance of incorporating trophic relationships into ecosystem models, which will help to enhance our understanding of the complexity of the trophic structure of fish communities. [ABSTRACT FROM AUTHOR]

Species of the catfish genus Rineloricaria are common in the Paraíba do Sul River basin, in southeastern Brazil; here we present a revision of the taxonomic diversity and geographic distribution of the species of the genus inhabiting the basin, based on novel morphologic and molecular data. Five species delimitation methods based on cytochrome C oxidase subunit 1 nucleotide sequences yielded comparable molecular operational taxonomic units. The automatic barcode gap discovery, assemble species by automatic partitioning, barcode index number, and Bayesian implementation of the Poisson tree process methods supported the recognition of five evolutionary lineages. These taxonomic units were assigned to the previously described Rineloricaria nigricauda, Rineloricaria steindachneri, Rineloricaria zawadzkii, and Rineloricaria nudipectoris, and an additional undescribed species. R. zawadzkii was further divided into two intraspecific geographically structured lineages using the generalized mixed Yule coalescent delimitation method. A maximum likelihood phylogenetic analysis revealed that the five lineages from the Paraíba do Sul have closer relationships to different species from southern and southeastern Brazil (Ribeira de Iguape, Lagoa dos Patos, Uruguay, Paraguay, and Parana river basins) than to each other. Based on the analysis of lectotypes, recently collected material, and specimens from ichthyological collections, the poorly described R. nigricauda and R. steindachneri are redescribed following current descriptive standards. The undescribed species from the middle and upper Paraíba do Sul River basin is formally described. The description of a new species, along with the description of species boundaries in R. nigricauda and R. steindachneri, contributes to the knowledge of the ichthyofauna of the Paraíba do Sul River basin and adjacent coastal drainages of southeastern Brazil. An identification key for the species of Rineloricaria occurring in the Paraíba do Sul River basin is provided. [ABSTRACT FROM AUTHOR]

In recent decades, hypoxic areas have rapidly expanded worldwide in estuaries and coastal zones. The Pearl River Estuary (PRE), one of China's largest estuaries, experiences frequent seasonal hypoxia due to intense human activities and eutrophication. However, the ecological effects of hypoxia in the PRE, particularly on fish communities, remain unclear. To explore these effects, we collected fish community and environmental data in July 2021 during the summer hypoxia development period. The results revealed that bottom‐layer dissolved oxygen (DO) in the PRE ranged from 0.08 to 5.71 mg/L, with extensive hypoxic zones (DO ≤ 2 mg/L) observed. Hypoxia has varied effects on fish community composition, distribution, species, and functional diversity in the PRE. A total of 104 fish species were collected in this study, with approximately 30 species (28.6%) exclusively found in hypoxic areas. Species responses to hypoxia varied: species such as Sardinella zunasi, Coilia mystus, and Nuchequula nuchalis were sensitive, while Decapterus maruadsi, Siganus fuscescens, and Lagocephalus spadiceus showed higher tolerance. Within the hypoxia area, dissolved oxygen was the main limiting factor for fish community diversity. Functional diversity (FDiv) decreased with higher dissolved oxygen levels, indicating a potential shift in the functional traits and ecological roles of fish species in response to changing oxygen conditions. Further analysis demonstrated that dissolved oxygen had a significantly stronger effect on fish community structure at hypoxic sites than in the whole PRE. Moreover, other environmental variables also had significant effects on the fish community structure and interacted with dissolved oxygen in the hypoxia area. These findings suggest that maintaining sufficient dissolved oxygen levels is essential for sustaining fish communities and ecosystem health in the PRE. This study provides novel insights into the effects of hypoxia on fish communities in estuarine ecosystems and has significant implications for the ecological health and management of the PRE. [ABSTRACT FROM AUTHOR]

Fishing behavior is an important link between management decisions and bioeconomic outcomes. The diversity in fishers' behavior, motivations, and abilities should inform incentive structures if management aims to consider heterogeneous impacts on and by communities. Modeling human behavior in resource management is important for successful fisheries, especially for fisheries undergoing rapid transformation, such as the Alaskan snow crab fishery. This study modeled how snow crabbers choose where to fish in the eastern Bering Sea and examined the diversity of strategies among individuals by fitting a random utility model to data on fishing locations using a variety of potential drivers of behavior as covariates. The overall fishing strategy of the snow crab fleet prioritizes revenue and shared information, while avoiding risk, poor weather, and cost. Diversity of fishing strategies was driven by differences in spatial footprint, vessel size, and ports of landing. Larger vessels ventured farther north, where weather conditions are more extreme. Despite differences in vessel size, crabbers were spatially adaptive and switched fishing regions depending on the abundance and distribution of crab. These findings on the patterns of fishing strategies can inform better management of the Alaskan snow crab fishery as it undergoes rebuilding. [ABSTRACT FROM AUTHOR]

Flying fish (Exocoetidae) is a pelagic fishery commodity that holds economic value among the people of eastern Indonesia. Flying fish are advantageous as they are abundant in Indonesian sea waters, making them an affordable source of omega-3, which is beneficial for human health. However, the high demand for flying fish has resulted in overfishing, which poses a risk of reducing their natural population. Proper management of this commodity is necessary to minimize these risks. Effective management requires adequate information, including genetic diversity data. This study aims to determine the genetic diversity of flying fish in Southeast Sulawesi, specifically in the Banda Sea and Bone Bay populations. Tissue samples were collected from flying fish in the two populations during the study in March 2022. The results show that the genetic diversity values of flying fish in Bone Bay and the Banda Sea were 0.984 and 1.00, respectively, while the nucleotide diversity values were 0.021 and 0.018. High genetic diversity values and nucleotide diversity values were found between the two populations, with values of 0.990 and 0.020, respectively. Based on phylogenetic analysis, the two populations in Southeast Sulawesi are genetically similar. [ABSTRACT FROM AUTHOR]

Daya Bay is a semi-enclosed bay in the South China Sea which is a coastal ecosystem with significant ecological and economic value that is subjected to a variety of anthropogenic disturbances. However, long-term variation in fish community structure in this Bay remains uncertain. In this study, we aimed to explore the changing characteristics of fish species composition and community structure in Daya Bay during the past 30 years using data from 1989 to 2021 from bottom trawl surveys and historical literature data. As of now, a total of 544 species of fish have been identified in the Bay, belonging to 24 orders and 125 families. The structure of the fish community in the bay has changed over time. Firstly, there has been a clear decrease in the number of species and biomass of large fish. Secondly, the number of fish constituent orders and families has decreased. Moreover, both the average taxonomic distinctness and variation in taxonomic distinctness decreased from 1989 to 2021. Thirdly, there is low similarity among fishes at different time phases and distinct changes in the composition of dominant species. Present results indicate that the fish community structure in Daya Bay has tended to reflect a decline in diversity, shifts in composition, and shrinking of fish body size in the past 30 years. This study improves our understanding of fish species composition and its drivers over time in Daya Bay, providing important knowledge to support the protection and restoration of this ecosystem and the important ecosystem services it provides. [ABSTRACT FROM AUTHOR]

A diverse range of freshwater habitats may be found in the Mediterranean basin, which is also home to a rich variety of cyprinids, including the genus Barbus. Numerous factors pose a threat to this diversity, increasing the susceptibility of fish to parasitic infections. The current study attempted to investigate the Barbus's parasitic variety. In Morocco, publications concerning this subject are rare and limited to certain taxa and specific biogeographic zones. Patrick Berrebi (1983) is the first researcher to report the infestation of three species of Moroccan barbel from the Atlantic slope, by Myxobolus sp., whereas, El Gharbi and other collaborators (1994), based on morphological criteria, were able to describe fifteen new species of Monogeneans, in fifteen species of the genus Barbus. Then in recent years, Rahmouni and other colleagues (2017) identified four new species of Dactylogyrus in the gills of three species of Luciobarbus, originally collected by Heckel (1843) in different watersheds in northern Morocco. In Algeria, Meddour (2009) in his investigation of the fish parasitofauna of Lake Oubeira, was able to discover two cestodes and an acanthocephalan. While in the south of France, Alain Lambert (1977) identified two species of Monogenes among the fluviatile barbel in the station of La Chapelette (Bouches-du-Rhône). However, Batbus meridionnalis is the most commonly parasitized host species in Spain. The study of parasites in freshwater fish of the genus Barbus in the Mediterranean region has shown a lot of variation, but most research has only focused on certain types of parasites. This limits our understanding of the full range of parasites that infect these fish. [ABSTRACT FROM AUTHOR]

The Kuroshio-Oyashio confluence region of the Northwest Pacific Ocean is one of the most productive fishing areas, which is rich of fish resources. In order to understand the biodiversity of fish communities in the confluence region and to protect and exploit fishery resources properly' we used environmental DNA (eDNA) to analyze the fish diversity in the Kurishio-Oyashio confluence region during the summer. A total of 51 species of marine fishes (22 orders' 30 families and 44 genera) were detected among 22 water sampling stations using high-throughput sequencing analysis. The Myctophidae family was the richest in species, comprising 33.33% of the detected fish species. In addition' the primary species with higher relative abundance were Stenobrachius nannochir, Gonostoma atlanticum, Notoscopelus japonicus, Sardinops melanostictus, Takifugu poecilonotus, Ceratoscopelus warmingii, Hexagrammos agrammus, Scomber japonicus, Nematalosa japonica and Diaphus kuroshio. The alpha diversity among stations was obviously different, and there were higher biodiversity in low-latitude sections than that of high-latitude sections. Redundancy analysis showed that the content of dissolved oxygen was the main environment factor impacting the fish species composition. The results indicated that eDNA can be a useful method for monitoring fish diversity and spatial distribution in the Kuroshio-Oyashio confluence region. [ABSTRACT FROM AUTHOR]

With the unique geography and complex environment, the Northwest Pacific Ocean has nurtured extremely rich fishery resources, becoming a hotspot for global marine biodiversity conservation and fishery management. In order to more effectively identify and investigate the diversity of fish species, a local DNA barcodes database of common fish in Northwest Pacific Ocean was established. Based on the CO I gene sequences of fish, 307 samples of common fish were collected in Northwest Pacific Ocean from June to August 2023. These common fish belonged to 20 genera, 13 families, 7 orders, and 25 fish species. 77.96% of CO I sequences can be compared to high similarity sequences in public database. The average interspecific genetic distance was 0.233, and the average intraspecific genetic distance was 0.003, and the interspecific genetic distance was 77.67 times that of the intraspecific genetic distance, and it could form obvious bar code gap. The phylogenetic tree based on CO I gene sequences showed that fishes of the same genus first clustered into a single branch, then with fishes of the same family, and finally with fish of different families of the same order. In summary, the CO I gene has species specificity and can effectively distinguish common fish species in the Northwest Pacific Ocean. The initial establishment of the DNA barcode database of common fish is conducive to the monitoring and investigation of fish diversity in Northwest Pacific Ocean using environmental DNA technology, providing technical support for biodiversity conservation, resource management, and population dynamic monitoring in Northwest Pacific Ocean. [ABSTRACT FROM AUTHOR]

In order to explore the growth regularity of Scomber japonicus in Northwest Pacific Ocean, 210 samples collected by the "Songhang" from 2021 to 2022 used landmarks based on geometric morphometrics. Compared with other methods, the use of landmark methods can effectively reveal the phenotypic diversity of fish, reflect the changes in fish at different stages, and explore their individual growth regularity. The results showed that there were significant differences in the external morphology of S. japonicus across different fork length groups. Both principal component analysis and multivariate analysis of covariance showed that S. japonicus with smaller fork length had more distinct zones, with overlapping zones among the three different fork length groups. Different fork length groups had the same growth regularities. The growth rate of S. japonicus gradually decreased with increasing fork length. The thin-plate spline indicates that the smaller the fork length of S. japonicus, the smaller their abdomen and tail. The morphology of S. japonicus changes with the change of fork length. The conclusion is that the morphology of S. japonicus gradually changes with increasing fork length in Northwest Pacific Ocean. [ABSTRACT FROM AUTHOR]

The floodplain lakes of the Amazon constitute one of the most important aquatic systems in terms of fish biodiversity. These ecosystems are influenced by the flood pulse, which in turn, affects the behaviour of fish communities within this lake ecosystem. In this study, we tested the hypothesis that the facets of taxonomic and functional diversity may be influenced by the conditions of 'patches' of internal habitats, considering the margins and central environments of a floodplain lake in the Amazon. Lake Cujubim, located on the right bank of the Madeira River, was evaluated via fisheries carried out in the high‐water and low‐water phases, during the day and night, and considering two location strata. The results suggest that the absence of significant differences in alpha taxonomic diversity between the two phases may be a possible seasonal mischaracterisation in Lake Cujubim attributed mainly to dam constructions along the Madeira River. Apparently, no major differences occur in the assembly of fish in terms of their taxonomic and functional characteristics, regardless of luminosity. In the strata of the locations, demonstrates noticeable habitat patches, with the margins being bioregions with high incidences of individuals of the Engraulidae family, confirmed by both taxonomic and functional diversity (alpha and beta). It can be seen that, even in connected lakes, there are differentiated metacommunities between the bioregions, thus forming patches of habitat, and that the shores of the lake, especially those located in proximity or distant from the river, are more suitable areas for food and refuge. [ABSTRACT FROM AUTHOR]

This study examined preserved marine fish specimens collected from numerous field surveys conducted along Türkiye's Black Sea, Marmara, Aegean, and Mediterranean coasts since 1965. Our review and categorization of these materials revealed that the specimens belong to 360 species from 131 families. Current data shows that the museum collection includes 20 species of cartilaginous fish and 8 species of bony fish listed as endangered on the IUCN Red List, alongside 54 non-native fish species. Prepared according to museum standards by Ege University Fisheries Faculty's Scientific Material (ESFM), this collection of Turkish marine fish constitutes 66% of all Turkish marine fish fauna. This makes it the largest and oldest marine fish collection in Türkiye. Considering Türkiye's maritime borders with neighboring countries, this collection is significant nationally and globally. Given the diverse marine fish species in Turkish seas over the past half-century, this preserved material is a vital reference for local and foreign ichthyologists. If organized and transformed into a visitable museum, this extensive collection could raise awareness about the diversity of marine fish species in our seas. As a result, we have established the "biological repository of Turkish Marine Fish Department" in the Faculty Museum, now known as the Fisheries Faculty's Scientific Material (ESFM) at Ege University. We present the fish in the collection as a species list. [ABSTRACT FROM AUTHOR]

Seagrass meadows provide an important nursery and feeding habitat for fish, globally. However, limited data exist on how these vegetated coastal ecosystems affect local fish stocks over longer time periods. By means of beach seine hauling with a bio‐monitoring seine net, we collected fish data in Kronborg Bay (Denmark) over 4 years. The bay contains both vegetated and bare sediment areas in close proximity to Kronborg Castle in Elsinore and is part of the Øresund strait; a dynamic marine environment linking the Baltic Sea with the inner Danish waters (Kattegat). We investigated the biodiversity and fish abundance in a healthy seagrass meadow and compared it with a bare adjacent sediment area. We show that seagrass is important for fish species like the Atlantic cod, the two‐spotted goby, and the broadnosed pipefish. The seagrass meadow harboured more fish species and higher biodiversity, while the number of individuals was higher in the adjacent bare sediment area as a result of high abundances of lesser sand eel. Pilou's evenness and the Shannon‐Wiener index showed 2–4‐fold higher biodiversity in the seagrass meadow. The seagrass meadow harboured about 35% more fish species than the bare adjacent sediment. The Atlantic cod was almost entirely found in the seagrass meadow, while lesser sand eel that showed an overall increase in abundance in both habitats, represented the largest proportion of the total number of fish individuals (up to about 60%) and was mostly found on the bare adjacent sediment. Species abundance was analysed for changes over time, where, for example the European plaice showed an increase in abundance over the 4‐year period of investigation. Seagrass meadows can thus be very important for the Atlantic cod population in the Øresund strait and generally for local fish productivity, abundance and diversity. [ABSTRACT FROM AUTHOR]

Taylor's power law (TPL) describes the expected range of parameters of the mean–variance scaling relationship and has been extensively used in studies examining temporal variations in abundance. Few studies though have focused on biological and ecological covariates of TPL, while its statistical inherences have been extensively debated. In the present study, we focused on species‐specific features (i.e. functional traits) that could be influential to temporal TPL. We combined field surveys of 180 fish species from 972 sites varying from small streams to large rivers with data on 31 ecological traits describing species‐specific characteristics related to three main niche dimensions (trophic ecology, life history, and habitat use). For each species, the parameters of temporal TPL (intercept and slope) were estimated from the log–log mean–variance relationships while controlling for spatial dependencies and biological covariates (species richness and evenness). Then, we investigated whether functional traits explained variations in TPL parameters. Differences in TPL parameters among species were explained mostly by life history and environmental determinants, especially TPL slope. Life history was the main determinant of differences in TPL parameters and thereby aggregation patterns, with traits related to body size being the most influential, thus showing a high contrast between small‐sized species with short lifespans and large‐bodied migratory fishes, even after controlling for phylogenetic resemblances. We found that life history traits, especially those related to body size, mostly affect TPL and, as such, can be determinants of temporal variability of fish populations. We also found that statistical effects and phylogenetic resemblances are embedded in mean–variance relationships for fish, and that environmental drivers can interact with ecological characteristics of species in determining temporal fluctuations in abundance. [ABSTRACT FROM AUTHOR]

Objective: While North American fishes are often overlooked by the ornamental fish industry, there is growing interest in fishes native to the southeastern USA, a hot spot for fish diversity. The Metallic Shiner Pteronotropis metallicus, a small‐bodied leuciscid native to Florida and Georgia, is sometimes available in the ornamental fish trade through wild collection and limited captive production. This species exhibits a distinctive color pattern straddling the lateral line: a dorsal pink to red line, fading to a black to blue stripe. This group of minnows is largely unknown to ornamental aquaculture and lacks defined culture protocols. Our objective was to develop culture protocols for the Metallic Shiner. Methods: Following collection of wild broodstock, we used routine culture methods to experimentally determine substrate preference, egg incubation, egg disinfection, larval feeding, and larval development. Result: Metallic Shiner spawning was more successful on yarn mops compared with other media, with average output of >50 embryos per tank per day. Hatching success was similar for static incubators (24%) and upwelling incubators (20%) and was also similar among egg disinfection treatments (iodine, hydrogen peroxide, and formalin). Larval feeding regimes altered survival, with Otohime A1 exhibiting higher survival (44%) over 14 days posthatch (dph) and better growth than other feeding regimes. During the developmental trial with water temperature at a relatively constant 25°C, length increased from 5 mm notochord length (4 dph) to 8.7 mm standard length (45 dph), with significant milestones occurring at 4 dph (swim bladder inflation), 16 dph (flexion), and 23 dph (hypural plate formation). Conclusion: These data provide basic culture information for the Metallic Shiner while also providing a place of reference to begin investigating culture protocols for related species, including species of conservation concern. Impact statementThese data provide basic culture protocols to establish commercial production for the Metallic Shiner, an overlooked species native to North America. [ABSTRACT FROM AUTHOR]

Tropical ecosystems host a significant share of global fish diversity contributing substantially to the global fisheries sector. Yet their sustainable management is challenging due to their complexity, diverse life history traits of tropical fishes, and varied fishing techniques involved. Traditional monitoring techniques are often costly, labour-intensive, and/or difficult to apply in inaccessible sites. These limitations call for the adoption of innovative, sensitive, and cost-effective monitoring solutions, especially in a scenario of climate change. Environmental DNA (eDNA) emerges as a potential game changer for biodiversity monitoring and conservation, especially in aquatic ecosystems. However, its utility in tropical settings remains underexplored, primarily due to a series of challenges, including the need for a comprehensive barcode reference library, an understanding of eDNA behaviour in tropical aquatic environments, standardized procedures, and supportive biomonitoring policies. Despite these challenges, the potential of eDNA for sensitive species detection across varied habitats is evident, and its global use is accelerating in biodiversity conservation efforts. This review takes an in-depth look at the current state and prospects of eDNA-based monitoring in tropical fisheries management research. Additionally, a SWOT analysis is used to underscore the opportunities and threats, with the aim of bridging the knowledge gaps and guiding the more extensive and effective use of eDNA-based monitoring in tropical fisheries management. Although the discussion applies worldwide, some specific experiences and insights from Indian tropical fisheries are shared to illustrate the practical application and challenges of employing eDNA in a tropical context. [ABSTRACT FROM AUTHOR]

The study of length-weight relationship and condition factor was carried out on of freshwater catfish, Clupisoma garua. Altogether 280 samples were collected from three different rivers of North India (Gomti, Ganga and Rapti). The value of b ranges from 2.571-2.720 for the length-weight relationship in the current study. The growth pattern showed significant deviation from isometric value (b=3), therefore all the three populations are supposed to follow negative allometric growth pattern. The coefficient of determination (r2) was found to be in the range of 0.8059-0.8587. The value of condition factor in the present study was found to be more than '1' in all the three populations of the fish which indicated the good health conditions. The present study is considered to be important for assessment of the biology of the fish that could help in conservation and management of C. garua in the North Indian Rivers. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVES: The coasts around West Java, Indonesia are prospective fishing grounds due to their commercial fish diversity. The presence of neighboring settlements discharging waste, including microplastics, poses a threat to the estuarine ecosystem. This study aimed to quantify and classify microplastics in the tissues of Mugil cephalus, Eleutheronema tetradactylum, and Scatophagus argus. METHODS: This study takes place in the estuary of the Blanakan River, Subang Regency, an area renowned for its wide variety of commercially valuable fish. Four fish sampling sites were identified according to the predominant land use, with settlements in the upper reaches, ponds in the central area, and mangrove forests in the lower reaches. Fish samples were taken the gastrointestinal tract, gills and muscle to calculated the microplastic content and identify its shape and size. Raman spectroscopy was applied to verify the polymer of microplastic. Statistical analysis was conducted to evaluate variations in microplastic levels at the individual level across these fish species. FINDINGS: The findings indicated the presence of microplastics in the muscle, gastrointestinal tract, and gills of three commercially caught fish from Blanakan, with the muscle being identified as the edible part and the gastrointestinal tract and gills as the non-edible parts. The microplastics were classified according to shape and size and were found in the following order of abundance: Mugil cephalus, Scatophagus argus, Eleutheronema tetradactylum. Mugil cephalus contained the most microplastics (210.8 particles per individual), with the lowest amount recorded in Eleutheronema tetradactylum (41.9 particles per individual). The tissues of Eleutheronema tetradactylum exhibited varying levels of microplastic contamination, with the highest concentration found in the gastrointestinal tract, followed by the gills and muscles. In contrast, in the tissues of Mugil cephalus and Scatophagus argus, microplastics were found in the following order of abundance from high to low: muscle, gastrointestinal tract, gill. The muscle of Mugil cephalus contained the highest microplastic concentration (28.71 particles per gram wet weight), while the lowest was recorded in the muscle of Eleutheronema tetradactylum (3.42 particles per gram wet weight). Microplastics ranging from 300 to 1000 micrometers in size, in the form of fibers and fragments, were commonly found in fish tissues. CONCLUSION: Microplastic content is found most abundantly in the gastrointestinal tract and muscle. This indicates that feeding and ingestion play a role in the entry of microplastics into the fish's body. Given that the fish falls under the category of commercial and consumption fish, there is a significant concern regarding environmental pollution caused by microplastics and the potential health hazards linked to its consumption. [ABSTRACT FROM AUTHOR]

In naturally flowing waters, communities are expected to increase their taxonomic and functional diversity as well as increase the complexity of food web architecture along the longitudinal gradient from headwaters to mouth. However, these theories do not necessarily apply to dammed rivers. We analysed fish communities at 12 locations along the 1700 km stretch of the transnational Uruguay River. We determined species richness, beta-diversity and its components (turnover and nestedness), trophic diversity, and isotopic niches at community level, with particular focus on areas upstream and downstream of the four existing dams. We estimated trophic diversity metrics based on diet analysis, and isotopic niche breadth based on Bayesian isotopic niche models. We detected consistent longitudinal changes, supporting predictions from the River Continuum Concept. However, taxonomic richness, trophic diversity, and isotopic niche decreased abruptly immediately downstream of dams, and the component contributing the most to beta diversity was turnover, with the highest values occurring mainly after the cascade of dams in the upper Uruguay River, fitting expectations from the Serial Discontinuity Concept. The dam-free stretches of the Uruguay River allowed the recovery of ecological diversity as fish richness and trophic and isotopic niche increased. The negative impacts of dams should urgently be considered in the Neotropics, where many large dams are projected.