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Over one third of sharks, rays and chimaeras (chondrichthyans) are threatened with extinction globally. In the Mediterranean Sea, more than half of chondrichthyan species face this risk, although a variety of international, regional, and national rules and regulations apply directly and indirectly targeting management and conservation for these species. In this work, we provide an overview of relevant legislation and policies in the region, which regulate, inter alia, commercial fisheries, while highlighting through cases studies how implementation in practice at national level looks like. Horizontal gaps and inconsistencies that hinder chondrichthyan management in the region are also illustrated. Furthermore, we present recommendations for improvement and additional tools that can be used, even if not originally or explicitly targeting chondrichthyans, for improving the management of these taxa in the Mediterranean. [ABSTRACT FROM AUTHOR]

The present study was conducted to document the fish fauna and their IUCN status of Chessore sub-division of Shamator, Nagaland for a period of one year, from May 2023 - April 2024 covering the targeted areas. The survey reveals the presence of 20 species belonging to 5 orders, 9 families and 15 genera. The order Cypriniformes dominanted with 14 species while Anabantiformes, Perciform and Synbranchiformes with 1 species each is the least common. According to IUCN Red-list and habitat studies during different seasons, one species belonging to family cyprinidae is under IUCN-NT category, five species belonging to cyprinidae, channidae and cobitidae is under IUCN-VU while the rest falls under IUCN-LC and Data deficient (DD) category. A primary threat to the fish biodiversity in study area is due to anthropogenic activities and environmental changes. [ABSTRACT FROM AUTHOR]

Context: Data on chondrichthyan (sharks, rays, and chimaeras) populations is largely lacking for many countries and territories in the Indo-Pacific. Aims: This study aims to provide a desktop review and information synthesis of the biodiversity, threats, and conservation of chondrichthyans in the Samoan archipelago (Samoa and American Samoa), focusing on their interactions with fisheries and exploring their social, cultural, and economic values. Methods: This study uses various literature sources, citizen science, and in-country engagement to assemble a review of current available information on chondrichthyans. Key results: A total of 67 chondrichthyans were documented to be present or potentially present in Samoa and American Samoa, consisting of 23 ray species and 44 shark species. Thirty-six of these species were listed in Threatened categories on the International Union for the Conservation of Nature Red List of Threatened Species. A biological productivity analysis conducted for species with sufficient information indicated that the silvertip shark (Carcharhinus albimarginatus), silky shark (Carcharhinus falciformis), bull shark (Carcharhinus leucas), oceanic whitetip (Carcharhinus longimanus), and whitetip reef shark (Triaenodon obesus) had the highest relative productivities. Conclusions: Both Samoa and American Samoa have relatively diverse shark and ray communities with management plans in place to protect chondrichthyans. These include participation in Western and Central Pacific Fisheries Commission initiatives, spatial protections, and community-based management programs. Implications: Current management approaches have the potential to provide significant protection to sharks and rays, however, their effectiveness may be hindered by a lack of proper enforcement, or compliance at the national and community levels. This study provides an insight into the species of Chondrichthyes (sharks, rays, and chimaeras) present in the Samoan archipelago, an overview of their conservation, and the dynamics surrounding their management and social, cultural, and economic importance. It highlights current knowledge gaps and provides a foundation for further research to better understand chondrichthyan biodiversity and conservation. [ABSTRACT FROM AUTHOR]

The expansion of marine protected areas (MPAs) is a core focus of global conservation efforts, with the "30x30" initiative to protect 30% of the ocean by 2030 serving as a prominent example of this trend. We consider a series of proposed MPA network expansions of various sizes, and we forecast the impact this increase in protection would have on global patterns of fishing effort. We do so by building a predictive machine learning model trained on a global dataset of satellite-based fishing vessel monitoring data, current MPA locations, and spatiotemporal environmental, geographic, political, and economic features. We then use this model to predict future fishing effort under various MPA expansion scenarios compared to a business-as-usual counterfactual scenario that includes no new MPAs. The difference between these scenarios represents the predicted change in fishing effort associated with MPA expansion. We find that regardless of the MPA network objectives or size, fishing effort would decrease inside the MPAs, though by much less than 100%. Moreover, we find that the reduction in fishing effort inside MPAs does not simply redistribute outside--rather, fishing effort outside MPAs would also decline. The overall magnitude of the predicted decrease in global fishing effort principally depends on where networks are placed in relation to existing fishing effort. MPA expansion will lead to a global redistribution of fishing effort that should be accounted for in network design, implementation, and impact evaluation. [ABSTRACT FROM AUTHOR]

Biodiversity conservation entails not only the preservation of specific taxa but also genetic diversity. Despite the crucial role of molecular data in freshwater fish conservation management, there is a scarcity of information regarding the genetic diversity of Luciobarbus Heckel, 1843 (Actinopterygii, Cyprinidae) populations in the Aral system. Therefore, the primary aim of this study was to provide genetic information on two native species of the Luciobarbus genus found in the Aral system: L. conocephalus (Kessler, 1872) and L. brachycephalus (Kessler, 1872). These species, like many others in the Aral system, confront the imminent threat of extinction due to system alterations. However, genetic studies on these species at the nuclear level are challenging because Luciobarbus is an allotetraploid genus. Consequently, genetic investigations thus far have focused mainly on sequencing mitochondrial genes due to their haploid nature. This study has successfully developed fifteen new polymorphic microsatellite loci, which can prove to be valuable for population genetics, conservation, and other pertinent research on these species. [ABSTRACT FROM AUTHOR]

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

The European mudminnow (Umbra krameri Walbaum, 1792) is a freshwater fish species with scattered distribution in the Danube and Dniester drainages, being the only native member of the Umbridae family in Europe. It inhabits irrigation canals, slow flowing and stagnant waters with dense vegetation, such as small ditches, oxbows and backwaters. In Croatia, it was first mentioned in 1897 in the Drava River drainage, and later on was recorded in the Mura River and in several localities of the Sava watershed. We studied 212 localities and recorded the presence of the species in 26 of them in the Drava, Sava and Mura river systems in Croatia. We present the first comprehensive data on the distribution and habitat preferences of Umbra krameri in Croatia, including historical data and recent data collected in the last six years. Our results show that U. krameri is an abundant and prevalent species in several localities in the Drava River system. Field data shows the suitability of secondary habitats for U. krameri, such as artificial canals with intensive organic load and pollution from anthropogenic sources, as well as the Sava River system being the southern border of the distribution of this species. [ABSTRACT FROM AUTHOR]

This study presents a survey of small-stream fish species from the Purus-Madeira interfluve, collected in four streams near Humaitá on the highway BR-319. The results reveal a rich and diversified ichthyofauna with 3016 collected individuals distributed in 84 species, six orders, 25 families, and 60 genera. Of all the specimens collected, the Characiformes was the most representative, with eight families, 26 genera, and 42 species, followed Siluriformes, with nine families, 20 genera, and 23 species. In terms of families, Characidae had the highest number of species (25), followed by Loricariidae (9), and Cichlidae (8). Among the 95 captured species's 11 are the first records for the region, evidencing a high diversity in these environments. Of the 84 species recorded in this study, 15 have not been assessed by the IUCN, while the remaining 62 include 23 listed as Least Concern (LC), three as data deficient (DD), and one as Near Threatened (NT). The southeastern Amazon region still has few fish surveys, especially in the region comprising the Purus-Madeira Interfluve, which highlights the importance of surveys to fill gaps and understand the biodiversity distribution patterns in the region. [ABSTRACT FROM AUTHOR]

Connectivity is a foundational concept in ecology and conservation and was the organising theme for the 2022 Annual Meeting of the Southeastern Fishes Council, a professional organisation dedicated to the study and conservation of freshwater fishes native to the southeast region of the United States (US). We introduce a Special Contribution of five papers selected from presentations at that meeting that illustrate perspectives on connections created by fish migration and dispersal, evolved life histories and habitat affinities and interspecific facilitation. Although focused on streams of the southeast US, each of these topics is broadly relevant to freshwater fish conservation, particularly with respect to causes and consequences of migratory fish depletion, population fragmentation and species declines. Many other connections relevant to the ecology and conservation of freshwater fishes remain relatively unexplored but could substantively advance conservation. We highlight the potential that species evolutionary histories, that is connections through time, reconstructed using species distributions and phylogenies may improve predictions of species responses to environmental change. Identifying species interdependencies, including undiscovered interactions that support survival or reproduction, could provide insights into how species losses may cascade as aquatic communities unravel. Finally, efforts to elucidate diverse connections between people and freshwater biodiversity, particularly where fisheries are historic and streams mostly go unnoticed, may prove essential to building public support for conservation measures. A research agenda anchored on 'biodiversity connections' has the potential to advance ecological understanding and public engagement, elements essential to conserving freshwater fishes. [ABSTRACT FROM AUTHOR]

Freshwater-limited fish populations are often tightly constrained by river drainage boundaries. As a case in point, the distribution of lineages within New Zealand's diverse Galaxias vulgaris complex is broadly structured by geographic barriers, reflecting tectonic processes. However, several drainages of the Central Otago region have been locally modified by past gold-mining activities, with artificial water races connecting formerly isolated headwaters of distinct river drainage systems. Here we synthesise published genetic data to highlight the role of anthropogenic catchment modification in redistributing fish diversity. These data show that several local phylogeographic anomalies for stream-resident Galaxias fishes are closely linked to anthropogenic connections across major drainage divides. While these anthropogenic translocations may parallel natural geologically-driven mixing events that occur on deeper time scales, they nevertheless have potential conservation implications given the increasing fragmentation of native fish populations. Our review also highlights the role of sub-catchment units in shaping the hierarchical structure of intraspecific biodiversity. [ABSTRACT FROM AUTHOR]

Fish deformities are detrimental to aquaculture and conservation initiatives; it is also an ethical problem and causes substantial financial losses to the aquaculture industry. The exact mechanism of deformities is still a mystery. Several factors cause deformities in fish; it seems that the deformations are inevitable but can be minimised by adopting good aquaculture practices such as proper broodstock husbandry, standard breeding and larval rearing protocol, management of water quality parameters, and providing nutritionally balanced feed, especially to the broodstock and developing larvae. In addition, it can be minimised by early detection of deformities, especially at the embryonic and larval stages. Monitoring of stocking materials should be an essential part of responsible aquaculture and conservation programmes; stocking materials should be free from any types of deformities as it affects not only aquaculture production, profitability and success of conservation programmes but also the reoccurrence of deformities in nature. The mechanism behind deformities and the development of low‐cost, robust methods/tools for detecting deformities in fish remain a challenge. Still, the opportunity exists to develop a robust marker that can predict deformities even at early embryonic and larval stages. [ABSTRACT FROM AUTHOR]

The 2010 Gulf of Mexico Deepwater Horizon was the largest oil spill in human history that occurred during a 12-week period in a region less than 100 km from the coast of Louisiana; however, after more than a decade of post-spill research, few definitives can be said to be known about the long-term impacts on the development and distribution of fishes in and around the region of the disaster. Here, we examine endemic Gulf of Mexico fish species that may have been most impacted by noting their past distributions in the region of the spill and examining data of known collecting events and observations over the last twenty years (ten years prior to the spill, ten years post-spill). Five years post-spill, it was reported that 48 of the Gulf's endemic fish species had not been collected and, with expanded methods, we now report that 29 (of the 78 endemic species) have not been reported in collections since 2010 (five of these are only known from observations post-spill). Although the good news that some previously 'missing' species have been found may be cause to celebrate, the lack of information for many species remains a cause for concern given focused sampling efforts post-spill. [ABSTRACT FROM AUTHOR]

Freshwater ecosystems are experiencing accelerating global biodiversity loss. Thus, knowing where these unique ecosystems' species richness reaches a peak can facilitate their conservation planning. By hosting more than 290 freshwater fishes, Iran is a major freshwater fish hotspot in the Middle East. Considering the accelerating rate of biodiversity loss, there is an urgent need to identify species‐rich areas and understand the mechanisms driving biodiversity distribution. In this study, we gathered distribution records of all endemic freshwater fishes of Iran (85 species) to develop their richness map and determine the most critical drivers of their richness patterns from an ecoregion approach. We performed a generalized linear model (GLM) with quasi‐Poisson distribution to identify contemporary and historical determinants of endemic freshwater fish richness. We also quantified endemic fish similarity among the 15 freshwater ecoregions of Iran. Results showed that endemic freshwater fish richness is highest in the Zagros Mountains while a moderate level of richness was observed between Zagros and Alborz Mountains. High, moderate, and low richness of endemic freshwater fish match with Upper Tigris & Euphrates, Namak, and Kavir & Lut Deserts ecoregions respectively. Kura – South Caspian Drainages and Caspian Highlands were the most similar ecoregions and Orumiyeh was the most unique ecoregion according to endemic fish presence. Precipitation and precipitation change velocity since the Last Glacial Maximum were the most important predictors of endemic freshwater fish richness. Areas identified to have the highest species richness have high priority for the conservation of freshwater fish in Iran, therefore, should be considered in future protected areas development. [ABSTRACT FROM AUTHOR]

Ayer Hitam Utara State Park Forest (AHUSPF) is an invaluable sanctuary in Johor, the last remaining intact peat swamp forest reserve that hosts many species unique to this distinctive habitat. Some rapid surveys conducted from 2019 to 2022 recorded 40 species of freshwater fish within AHUSPF. Notably, 11 are stenotopic to acid blackwater, and 12 are stenotopic to acid water, most belonging to the family Osphronemidae and Danionidae. The International Union for Conservation of Nature Red List has designated two species, Encheloclarias curtisoma and Betta persephone, as Endangered, while Betta omega is classified as Critically Endangered. The checklist presented herein was first produced from an inventory study in AHUSPF. The preservation of peat swamp forests in the area is under imminent threat due to the alarming rate of land conversion, forest fires, and the recent potential threat from the red-claw crayfish invasion in the aquatic environment. Hence, continuous monitoring is vital for documenting and updating the conservation status of the fish species. These endeavours will facilitate the development of practical conservation approaches to ensure the long-term sustainability of AHUSPF and its associated species. [ABSTRACT FROM AUTHOR]

Small‐scale fisheries are vital to millions of rural people, but surprisingly little is known about the environmental and socio‐economic factors that guide rural peoples' decisions to adopt a fishery‐oriented livelihood. We analyzed data from a large‐scale household survey of 3929 households in 235 rural communities in the Peruvian Amazon to develop multi‐scalar quantitative models to explain engagement in fishing and the relationship between fishing livelihoods and poverty. Households harvested an average of 1000 kg of fish and sold 450 kg over the 12 months preceding interviews. The mean total annual income was 3119 USD per household and fishing contributed 27% to total income. Access to extensive floodplain habitat, geographical isolation, and an available workforce were important drivers of fishing activity, while poor market connectivity and limited financial capital restricted households from increasing the scale of market‐oriented fishing. Wealthier households generally harvested more fish, whereas reliance on fisheries was greatest among poorer households who harvested less fish. Fisheries management and conservation initiatives in developing regions must consider the distinct drivers of fishing specialization across the full wealth spectrum with particular attention to "high reliance‐high harvest" households. [ABSTRACT FROM AUTHOR]

Intraspecific functional variation is critical for adaptation to rapidly changing environments. For visual opsins, functional variation can be characterized in vitro and often reflects a species' ecological niche but is rarely considered in the context of intraspecific variation or the impact of recent environmental changes on species of cultural or commercial significance. Investigation of adaptation in postglacial lakes can provide key insight into how rapid environmental changes impact functional evolution. Here, we report evidence for molecular adaptation in vision in 2 lineages of Nearctic fishes that are deep lake specialists: ciscoes and deepwater sculpin. We found depth-related variation in the dim-light visual pigment rhodopsin that evolved convergently in these 2 lineages. In vitro characterization of spectral sensitivity of the convergent deepwater rhodopsin alleles revealed blue-shifts compared with other more widely distributed alleles. These blue-shifted rhodopsin alleles were only observed in deep clear postglacial lakes with underwater visual environments enriched in blue light. This provides evidence of remarkably rapid and convergent visual adaptation and intraspecific functional variation in rhodopsin. Intraspecific functional variation has important implications for conservation, and these fishes are of conservation concern and great cultural, commercial, and nutritional importance to Indigenous communities. We collaborated with the Saugeen Ojibway Nation to develop and test a metabarcoding approach that we show is efficient and accurate in recovering the ecological distribution of functionally relevant variation in rhodopsin. Our approach bridges experimental analyses of protein function and genetics-based tools used in large-scale surveys to better understand the ecological extent of adaptive functional variation. [ABSTRACT FROM AUTHOR]

Walleye is an important sportfish across eastern North America, is commercially fished in the Laurentian Great Lakes region, and has been introduced outside its native range. Thirty-eight Walleye populations within six watersheds across the Eastern Highlands and other portions of the native range were screened at eight microsatellite DNA loci to better understand evolutionary history and to inform fishery management and conservation efforts. Population genetic variation showed divergent assemblages of populations, respectively, living in the Mobile Bay, Mississippi River, Eastern Highlands (Tennessee, New, and Ohio Rivers), and Great Lakes drainages today. All estimates of effective numbers of breeding individuals were under 25, and all populations within all watersheds had ~15–20% inter-individual relatedness, likely attributable to the effects of both natural demographic processes and stocking. The extent of Eastern Highlands Walleye includes both the Ohio and Tennessee River basins. [ABSTRACT FROM AUTHOR]

The Pacific seahorse (Hippocampus ingens) is a teleost fish native to the Pacific Ocean. In Mexico they are protected by national legislation; however, there are no studies regarding their commercial use or population status. From a conservation perspective they are a threatened fish and from a socio‐economic aspect they represent a source of income for many fishing communities. The integration of these two points of view requires, among other things, the recognition that fishers have knowledge and skills that can help implement conservation strategies and management plans for seahorses and their habitats.The objective was to document the knowledge of fishers from Sinaloa about the fishing status and current commercialization of wild populations of H. ingens. For this, semi‐structured interviews and participatory observation were carried out with 112 participants in the two main ports of the state of Sinaloa (Mazatlán and Topolobampo) from July to August 2021. The data obtained were coded and then, through content analysis, systematized results were obtained that allowed a qualitative and quantitative analysis.The species was found to be caught using six different fishing gears (catch per unit effort, CPUE = 0.07–1.24 seahorses per boat per day) and have an important financial value. Most fishers catch seahorses incidentally, but three of them mentioned targeting them directly. Fishers perceive a decrease in catches and in the size of the Pacific seahorse, as well as an increase in prices.The information analysed indicates that seahorse populations in Sinaloa are exploited and have economic value, despite current regulations. This study shows that the exploitation of seahorses in Sinaloa is unsustainable and requires the implemention of collaborative management strategies (e.g. stakeholder management, the establishment of marine protected areas, sustainable harvest practices, community‐based enforcement efforts, educational campaigns, research, and conservation partnerships) that fully take into account the knowledge and practice of local fishers of Sinaloa and Mexico. [ABSTRACT FROM AUTHOR]

This research paper presents the first comprehensive assessment of ichthyofaunal diversity in Hisar district, conducted from October 2021 to March 2022. This study summarized fortnightly field data from the fish market and local fish farmer ponds. A total of 12 fish species belonging to 4 orders, 7 families and 12 genera were recorded in Hisar district. The order Cypriniformes was found to be the most dominant, with the Cyprinidae family being the most prevalent. Indian major carp, along with exotic carp, constituted a significant portion of the fish catch in Hisar district. The conservation status analysis revealed that 50% of the species were categorised as least concerned, 17% as near threatened, 17% as vulnerable, and 16% as nearly endangered. This study provides valuable insights into the ichthyofaunal diversity of Hisar district, contributing to our understanding of the local fish populations and their conservation needs. [ABSTRACT FROM AUTHOR]

Medicinal leeches are known to primarily inhabit shallow parts of wetlands, which have unique physical, chemical, and biological properties that differ from the main bodies of water in these areas. However, limited research has been conducted on fish diversity and abundance in these habitats. This study aimed to investigate the fish diversity and abundance in the wetlands surrounding Lake Eğirdir (Turkey), where medicinal leeches are known to be present, and discuss the importance of conserving these habitats. Common diversity indices were used to estimate species richness, abundance, and biomass. A total of 416 fish from six species (Aphanius anatoliae, Carassius gibelio, Gambusia holbrooki, Pseudophoxinus egridiri, Pseudorasbora parva, and Seminemacheilus ispartensis) were sampled. The results showed that the species richness was lower in the studied wetlands (six species) compared to the lake itself (13 species), with the dominant species in terms of abundance and biomass being G. holbrooki (44.95%) and C. gibelio (33.46%). The presence of invasive and endemic species plays an important role in shaping the diversity and abundance of the fish community. The study found that there is compatibility between fish diversity and medicinal leeches in wetlands, and that fish species and their sizes provide feeding opportunities in favor of medicinal leeches. The wetlands also provide a protected area for the conservation of two IUCN red-listed fish species (P. egridiri and A. anatoliae). Thus, the study highlights the importance of conserving these habitats for maintaining the ecological unity, harmony, and sustainability of both medicinal leeches and fish populations. [ABSTRACT FROM AUTHOR]

Most of the waterbodies in Bangladesh's north-eastern haor basin have seen a gradual decline in their biodiversity, but little study has been done to determine their current condition. To address this issue, this research was conducted in the Malam beel under the Hakaluki haor - one of the largest wetland resources of the country. The study was conducted using a pre-tested questionnaire and a direct catch assessment survey in the beel. From 11 orders and 32 families, a total of 69 fish and shellfish species were identified. Of the species documented, 15.94% were classified as abundant, 39.13% were common, 27.54% were moderately available, and 17.39% were rare. Among the orders, Cypriniformes accounted for 37.68% of the total fish recorded. The most prevalent family was Cyprinidae found in Malam beel. Based on the findings, it can be concluded that Malam beel is a highly valuable inland open water body that has the potential to function as a key source of fishery resources as well as a gene bank for various fish species. However, some manmade and natural threats such as fishing by dewatering, brush pile fishing, illegal/destructive fishing and siltation were identified during the present study. Therefore, to ensure the sustainable maintenance of these water bodies, ecosystem-based fisheries management involving the local community is strongly advised. [ABSTRACT FROM AUTHOR]

Objective: Silver Chub Macrhybopsis storeriana, a predominately riverine species throughout its native range, exists within Lake Erie as the only known lake population. Its population declined in the 1950s and never fully recovered. Canada has listed Silver Chub in the Great Lakes–St. Lawrence River as endangered and has initiated a recovery plan that recognized the identification of spawning areas as a critical component to inform Silver Chub's recovery potential. Methods: We investigated potential spawning locations of Silver Chub using capture records, otolith microchemistry, and daily age analysis. Lapillus otolith Sr:Ca ratios from 27 age‐0 Silver Chub were used to identify potential spawning areas. Daily ages estimated from lapilli were used to calculate hatch dates, which then were compared with capture data of adults and river flows to further inform potential spawning areas. Result: The Detroit River (and its nearshore area) was all but ruled out as a potential spawning location. The Maumee, Portage, and Sandusky rivers or their nearshore areas were all possible spawning locations. Projected hatch dates spanned the end of May through the end of June and occurred across a wide range of flows, although some peaks in hatch dates corresponded to flow peaks, indicating recruitment is potentially enhanced by high flows. Conclusion: Silver Chub spawning period and hypothesized spawning rivers or lacustuaries overlap those of invasive Grass Carp Ctenopharyngodon idella, creating a need to jointly consider Grass Carp control efforts with conservation of Silver Chub when assessing management alternatives. Further research on spawning guild and the use of rivers themselves or nearshore areas influenced by rivers as spawning areas are required to maximize potential for conservation and recovery of Silver Chub. Impact statementConserving the Silver Chub is vital; it's an indicator of water quality, a food source for aquatic organisms, and preserves biodiversity. Identifying both locations and mode of spawning enhances the conservation of biodiversity in fish communities, ensuring ecosystem stability. [ABSTRACT FROM AUTHOR]

Fred Utter died in his sleep during the night of 5 March 2023 at the age of 91. In this paper, 3 friends and colleagues of Fred describe the important role that his genetics research has played in the management and conservation of fish populations. [ABSTRACT FROM AUTHOR]

An annotated checklist of the ichthyofauna of the Upemba National Park, draining part of the Upper Lualaba basin and situated in the southern part of the Democratic Republic of the Congo, is presented, based on a literature review, a re-examination of museum collections, and a study of recent collections (2012–2020). In total, 247 native and 1 introduced species, Heterotis niloticus, are reported. The native species belong to 78 genera, 26 families, and 15 orders. Of these, 45 species (18%) are endemic to the park, 35 species (14%) await formal description, and 5 taxa (2%) need further study to clarify their status. With 51 species, the Cyprinidae is by far the most species-rich family, followed by the Mormyridae (26), Mochokidae (26), Alestidae (18), Distichodontidae (18), Amphiliidae (17), and Cichlidae (16). The remaining families are represented by less than 15 species. Comments about the species distribution and the fish fauna shared with adjacent ecoregions are provided. Although the park provides some protection for the fish species living within its borders by limiting human access to the core zone, the annex and buffer zones are both subject to strong anthropogenic pressure. These observations underscore the need for the implementation and further elaboration of fish-related preservation guidelines and plans to enable better protection/conservation of the park's ichthyofauna. [ABSTRACT FROM AUTHOR]

Understanding movement and dispersal is critical for fisheries management and conservation, but many studies rely on tagging and telemetry, which can be costly and labor-intensive. Recent research on Atlantic bonefish (Albula vulpes) has shown that gill microbiomes vary among populations, raising the possibility that microbial communities might prove useful for inferring movement and dispersal. Here, we used bacterial 16S metabarcoding to characterize the structure and composition of the gill microbiomes of 253 A. vulpes from five areas spanning nearly 2000 km throughout their western Atlantic range. We compared gill microbiomes among areas and among nearby locations within areas, and we also compared gill microbiomes to seawater samples collected from the same sampling sites at the same times. We then used machine learning (ML) models to determine whether gill microbiomes accurately predict/recover the location from which a fish was sampled. Gill microbiomes varied among areas and locations, consistent with previous findings, and differed markedly from microbiomes of seawater samples. ML models predicted the geographic origin of a bonefish with 95 and 84% accuracy on the larger scale of area and the smaller scale of location, respectively, demonstrating the utility of the method. Additionally, gill microbiomes from bonefish in Florida were enriched for potentially disease-causing bacterial genera compared to microbiomes from bonefish sampled elsewhere. This result concords with previous findings, suggesting that Florida's historical bonefish population declines may be linked to health impairments resulting from pollution, runoff, and elevated bacterial inputs into coastal waters from anthropogenic factors such as urbanization and agricultural intensification. [ABSTRACT FROM AUTHOR]

Background: Fish are considered as bio-indicators of the health of aquatic ecosystems. Recently, native fish species were declining due to anthropogenic pollution and records of fish availability in a specific area of the Padma Riverine System aided in understanding the current status of fish and which fish need conservation. Methods: The fish diversity in Murshidabad district's Padma River was studied for twelve months, from October 2021 to September 2022, with the help of local fishermen. Freshly caught fish is immediately transported to a laboratory, identification is followed by Talwar and Jhingran (1991) and Rahman (2005) techniques. Result: A total of 49 fish species belonging to 11 orders, 24 families were recorded. Siluriformes (17 species) had the most dominance, followed by cypriniformes (12 species) and anabantiformes. Among the species collected, eight were threatened, thirty were less threatened, one was extremely rare and one had not yet had their status determined. These fishes were classified as threatened (16.33%), less threatened (61.23%) and exceedingly rare (2%). Based on the findings, it is concluded that the Padma River could be used as a refuge for the conservation of Murshidabad's threatened freshwater fishes. [ABSTRACT FROM AUTHOR]

The tropical gar (Atractosteus tropicus) is the smallest member of the family Lepisosteidae; yet this species has a large socioeconomic impact in México and Central America where it is traditionally harvested commercially and for subsistence. While natural populations of tropical gar have been dwindling throughout its natural range, it is also an emergent aquaculture species that is produced in local hatcheries and grown out in privately owned ponds. The increased pressure on natural populations of A. tropicus and its increasing use in aquaculture production poses potential conflicts for the management and conservation of natural populations. Here, we investigated the population genetic structure of tropical gar populations, including over 200 individuals sampled in México, El Salvador, and Costa Rica. Using 11 microsatellite loci, we identified three genetic clusters with distinct geographic distributions, including a cluster in drainages along the Pacific versant of Central America, a cluster in the Grijalva and Usumacinta River basins that drain into the Gulf of México, and a cluster in the Río San Juan that drains into the Caribbean Sea. Given the degree of divergence observed, these results indicate the potential presence of evolutionary significant units within tropical gar that warrant separate fisheries and conservation management. We also found that tropical gar from an aquaculture facility along the Pacific versant of México were derived from Atlantic versant populations, indicating that individuals have already been translocated across biogeographic boundaries. We discuss how such translocations can negatively impact the natural population structure of tropical gar and provide recommendations for future research and aquaculture practices. [ABSTRACT FROM AUTHOR]

An ecosystem's ability to maintain key functions during environmental change is largely determined by its biodiversity. We compared fish species composition, richness, diversity, catch per unit effort (CPUE), and fish size between a 1.5 km2 no-take marine protected area (MPA) and a nearby fished area on the southern Norwegian coast annually for one decade (2011–2021), including before-protection status. In total, >26 thousand fish representing 31 species were sampled using a beach seine. No significant effect of protection was detected on either species richness, diversity, or evenness. For selected species of small-bodied intermediate predators, there was a significant decline in mean body size in the MPA area compared to the fished area, indicative of a response to protection involving trophic interactions. No significant effect of the MPA was detected on either CPUE or body size of Atlantic cod (Gadus morhua), a top predator mainly captured at the juvenile stage by our sampling. The limited responses seen in this study may be linked to the small size of the MPA compared to the dispersal and movement capabilities of species such as the cod. [ABSTRACT FROM AUTHOR]

The length-weight relationship parameter is important for obtaining fish weight and biomass data with relevant implications about species role on ecosystem functioning. Here we report the length-weight relationship (LWR) for 24 fish species from three streams located in the Atlantic Forest in the Rio de Janeiro State, Brazil. Fish were collected with electrofishing and standard length (cm) and wet weight (g) were measured to obtain the a and b parameters of the Log (W) = Log (a) + b Log (SL) equation. Length-weight relationships for seven out of 24 species (Hypostomus punctatus, Deuterodon taeniatus, Deuterodon hastatus, Deutorodon janeiroensis, Characidium vidali, Characidium interruptum and Rineloricaria zawadiskii) are reported for the first time. The length-weight relationships reported here contribute to the database that can support fish diversity conservation, fisheries management plans and studies on fish biology. [ABSTRACT FROM AUTHOR]

Aims: Climate change is expected to have profound effects on species' distributions into the future. Freshwater fishes, an important component of freshwater ecosystems, are no exception. Here, we project shifts in suitable conditions for Australian freshwater fishes under different climate change scenarios to identify species that may experience significant declines in habitat suitability. Location: Australia. Methods: We use MAXENT bioclimatic models to estimate the effect of climate change on the suitable conditions for 154 species of Australian freshwater fishes, of which 109 are endemic and 29 are threatened with extinction. Suitable conditions for freshwater fish species are modelled using three different Earth System climate models (ESMs) under two different emission scenarios to the year 2100. For each species, we examine potential geographic shifts in the distribution of suitable conditions from the present day to 2100 and quantify how habitat suitability may change at currently occupied sites by the end of this century. Results: Broadscale poleward shifts in suitable conditions are projected for Australian freshwater fishes by an average of up to 0.38° (~180 km) across all species, depending on the emission scenario. Considerable loss of suitable conditions is forecast to occur within currently recognized distributional extents by 2100, with a mean projected loss of up to 17.5% across species. Predicted geographic range shifts and declines are larger under a high‐emission scenario. Threatened species are projected to be more adversely affected than nonthreatened species. Main Conclusions: Our models identify species and geographic regions that may be vulnerable to climate change, enabling freshwater fish conservation into the future. [ABSTRACT FROM AUTHOR]

Every activity that involves exploitation of natural resources, such as fishing, needs to be organized and conducted based on information from monitoring programs to allow continuous evaluation. With the increasing fishing pressure in Brazil, the understanding of the importance of fisheries monitoring programs and how they can inform and assist in conservation decision-making remains limited. Based on the literature on fisheries and participatory conservation, we call attention to the need to generate information on the national fisheries sector in order to improve fisheries in the country. Given the context of the need to generate information on fishing stocks under exploitation, as well as to identify potential alternative fisheries and carry out various sectoral analyses in compliance with the 2030 Agenda for Sustainable Development, we present and discuss in the present paper the lack of a system of continuous fishing monitoring in Brazil and its effects on the fisheries sustainability in the country. [ABSTRACT FROM AUTHOR]

Tropical streams are among the most threatened ecosystems in the world. As such, studies carried out and compiled over spatial and temporal scales can provide useful information to examine patterns of species diversity and threats to their survival. Here we conducted a systematic review of published research on biological and ecological aspects of stream fish fauna found in the Piracicaba-Capivari-Jundiaí Basin, an industrial watershed of São Paulo State. We aimed to detect main patterns, trends and gaps in studies related to species composition, distribution, spatial and temporal scales, as well as in the covered topics. Results were related to main land uses, biomes and Conservation Units. A constant increase in published articles occurred from 2003 until 2016 with an average of 1.8 articles/year. Twenty-six publications were considered for the present study, reporting on fish samples obtained in 67 sites and resulting in 89 species. A high proportion of studies were concentrated in the Corumbataí sub-basin, and rarefaction curves indicated that stream fish richness in the PCJ Basin may be considerably higher than that shown by the actual numbers. Basin studies were unevenly distributed and did do not include such highly preserved areas as the Camanducaia, Jaguari and Jundiaí sub-basins. We emphasize the importance of further surveys in these regions, as well as in high priority conservation areas, which may lead to new insights for developing appropriate conservation strategies for this basin. [ABSTRACT FROM AUTHOR]

Freshwater biodiversity is declining faster than terrestrial and marine biodiversity. The protection and restoration of aquatic habitats are based, in part, on stemming this decline. We conducted a spatial conservation assessment of native fishes in the Lahontan and central Nevada basins using core-area zonation. The complementarity-based assessment yielded a landscape value (rank) of all subwatersheds (12-digit hydrologic unit code; ~12,000 ha) whereby high-ranking subwatersheds, as a set, maximized the representation of all native species, subspecies, and the within-species ecological diversity of salmonids, while accounting for aquatic connectivity and risk of aquatic habitat degradation. The high-ranking subwatersheds encapsulated small patches of habitat inhabited by endemic desert fishes, as in the Ash Meadows National Wildlife Refuge. They also highlighted clusters of high-value subwatersheds, such as in the Truckee River watershed that has extant populations of, and historical habitat for, Lahontan cutthroat trout in its headwaters, with species such as the mountain whitefish with migratory life histories, and endemic cui-ui, Chasmistes cujus, at Pyramid Lake—a terminal lake. Both the Truckee River headwaters and Pyramid Lake have been recipients of ongoing native fish conservation efforts. The landscape rankings will be used by the Desert Fish Habitat Partnership to inform regional conservation investments, and the rankings are available for broader use by resource agencies working on native fish conservation at landscape scales. [ABSTRACT FROM AUTHOR]

Coastal marine fisheries and the habitats that support them are under extensive and increasing pressures from numerous anthropogenic stressors that occur at multiple spatial and temporal scales and often intersect in unexpected ways. Frequently, the scales at which these fisheries are managed do not match the scales of the stressors, much less the geographic scale of species biology. In general, fishery management is ill prepared to address these stressors, as underscored by the continuing lack of integration of fisheries and habitat management. However, research of these fisheries is increasingly being conducted at spatial and temporal scales that incorporate biology and ecological connectivity of target species, with growing attention to the foundational role of habitat. These efforts are also increasingly engaging stakeholders and rights holders in research, education, and conservation. This multi-method approach is essential for addressing pressing conservation challenges that are common to flats ecosystems. Flats fisheries occur in the shallow, coastal habitat mosaic that supports fish species that are accessible to and desirable to target by recreational fishers. Because these species rely upon coastal habitats, the anthropogenic stressors can be especially intense—habitat alteration (loss and degradation) and water quality declines are being exacerbated by climate change and increasing direct human impacts (e.g., fishing effort, boat traffic, depredation, pollution). The connections necessary for effective flats conservation are of many modes and include ontogenetic habitat connectivity; connections between stressors and impacts to fishes; connections between research and management, such as research informing spawning area protections; and engagement of stakeholders and rights holders in research, education, and management. The articles included in this Special Issue build upon a growing literature that is filling knowledge gaps for flats fishes and their habitats and increasingly providing the evidence to inform resource management. Indeed, numerous articles in this issue propose or summarize direct application of research findings to management with a focus on current and future conservation challenges. As with many other fisheries, a revised approach to management and conservation is needed in the Anthropocene. [ABSTRACT FROM AUTHOR]

Pseudobarbus quathlambae (Barnard, 1938) is a cyprinid minnow with a disjunct distribution divided into tributaries of the Upper Orange River system in the Lesotho Highlands and the Mzimkhulu River system in KwaZulu Natal Province (KZN), South Africa. Recent records in the Mzimkhulu River system extended the species' geographic range, and this could represent the last remnant population of this species in South Africa. However, its future existence is in doubt, because of continued threats to all the remnant populations by non-native fishes, and more recently by the building of large, interconnected dams as part of the Lesotho Highlands Water Project (LHWP). One of these dams has directly affected the Mohale population in central Lesotho, which was the largest of the seven extant populations. Analysis of mitochondrial control region sequences (534 bp) revealed considerable genetic differentiation (2.3–6.4%) and geographic structuring amongst the remnant populations. The phylogenetic analysis identified three lineages within P. quathlambae: (i) one in KZN, (ii) a second one in eastern Lesotho and (iii) a third one in Mohale, central Lesotho. The deep genetic divergence and pronounced geographic structuring amongst the populations suggests a long period of isolation, indicating they represent unique evolutionary units. [ABSTRACT FROM AUTHOR]

Entrapment and subsequent drowning in fish fykes poses an anthropogenic mortality hazard to Eurasian otters (Lutra lutra). Different concepts on how to solve this problem have been debated in the past. To proactively prevent future fatal interactions and increase acceptance among fishers, this study tested two exit mechanisms for otters to safely escape from fyke nets, while still retaining full trap functionality for inland fisheries. Both exit options, a tearable latex lacing around flexible metal wires (100% success rate, n = 6) and a steel hoop‐spring construction (90%, n = 10) were successfully tested in 16 otter escape trials and 30 additional tests for fish (pike, eel, and common bream) retention (100%). The results indicate that the modifications of the fish traps were effective for otter conservation and commercial fisheries. Thus, both options can be recommended as equally good otter protection measures for fyke‐net fisheries of the tested type and similar sizes. However, these data were yielded under controlled conditions and it is possible that field results could differ. Hence, the presented results should be additionally verified under field conditions. [ABSTRACT FROM AUTHOR]

The aim of this study is to assess the population dynamics of medaka fish (Oryzias nigrimas) in Lake Poso. Three habitats of this fish were surveyed, including Watudilana waters, Tolambo village waters and Taipa village waters. Samples were collected at night using a petromax lamp to attract fish. The fishing gear used nets of 8 by 3 meters with a mesh size of 3 by 3 millimeters. A total of 685 individuals of medaka fish (Oryzias nigrimas) were used for population dynamics analysis. Standard length was used to compare the current size of the endemic medaka fish Oryzias nigrimas with its size 28 years ago, while total length was used to examine data on growth, mortality, exploitation rate, recruitment yield and potential reproductive ratio. The male to female sex ratio of this type of fish fluctuated each month, where females tended to be more abundant than males. The average length of this fish is smaller than the standard length in 1993. However, its average size is larger than the freshwater medaka species Oryzias asinua, Oryzias wolasi and Oryzias woworae from Southeast Sulawesi and Oryzias matanensis from Lake Sulaw Towuti. The mortality rate of the medaka fish Oryzias nigrimas is mainly caused by the presence of introduced species and overexploitation. Selectivity of fishing gear, especially by catching fish measuring more than 50.70 millimeters, is strongly recommended for the conservation effort of this fish species. [ABSTRACT FROM AUTHOR]

Movement of fishes in the aquatic realm is fundamental to their ecology and survival. Movement can be driven by a variety of biological, physiological and environmental factors occurring across all spatial and temporal scales. The intrinsic capacity of movement to impact fish individually (e.g., foraging) with potential knock‐on effects throughout the ecosystem (e.g., food web dynamics) has garnered considerable interest in the field of movement ecology. The advancement of technology in recent decades, in combination with ever‐growing threats to freshwater and marine systems, has further spurred empirical research and theoretical considerations. Given the rapid expansion within the field of movement ecology and its significant role in informing management and conservation efforts, a contemporary and multidisciplinary review about the various components influencing movement is outstanding. Using an established conceptual framework for movement ecology as a guide (i.e., Nathan et al., 2008: 19052), we synthesized the environmental and individual factors that affect the movement of fishes. Specifically, internal (e.g., energy acquisition, endocrinology, and homeostasis) and external (biotic and abiotic) environmental elements are discussed, as well as the different processes that influence individual‐level (or population) decisions, such as navigation cues, motion capacity, propagation characteristics and group behaviours. In addition to environmental drivers and individual movement factors, we also explored how associated strategies help survival by optimizing physiological and other biological states. Next, we identified how movement ecology is increasingly being incorporated into management and conservation by highlighting the inherent benefits that spatio‐temporal fish behaviour imbues into policy, regulatory, and remediation planning. Finally, we considered the future of movement ecology by evaluating ongoing technological innovations and both the challenges and opportunities that these advancements create for scientists and managers. As aquatic ecosystems continue to face alarming climate (and other human‐driven) issues that impact animal movements, the comprehensive and multidisciplinary assessment of movement ecology will be instrumental in developing plans to guide research and promote sustainability measures for aquatic resources. [ABSTRACT FROM AUTHOR]

Prediction of species' potentially suitable distribution areas and their range shifts under future climate change has long been the focus of macroecology and biogeography. Gymnocypris chilianensis of Schizothoracinae and Triplophysa hsutschouensis of Triplophysa are isolated to the Shiyang, Heihe, and Shule Rivers of the Hexi River system, listed from east to west, along the northeastern part of the Qinghai–Tibetan Plateau (QTP). This spatial distribution provides a valuable set of conditions for investigating patterns of habitat suitability and potential impacts of accelerated plateau climate change on endemic plateau fish species. Here, we employed the maximum entropy (MaxEnt) model to first evaluate potentially suitable habitats of the two species and identify the primary impact factors under the current climate based on occurrence records and environmental variables; then, we predicted changes in suitable habitat areas and distribution centers under two representative concentration pathways (RCPs), 2.6 and 8.5, for the future (2050 and 2070). The results showed that annual precipitation and altitude were the two most important environmental factors predicting the suitable habitat of G. chilianensis and T. hsutschouensis. The areas of suitable habitat for G. chilianensis and T. hsutschouensis experienced a sequential westward decrease from the Shiyang River towards the Heihe and Shule Rivers under the current climate conditions. Under future climate changes, the areas of the potential geographical distribution of G. chilianensis and T. hsutschouensis were concentrated eastward towards the Shiyang River, the area of the species' ancestral origins. Suitable habitat centers of the two species shifted eastward from the Heihe River to the Shiyang River and higher altitude areas. Additionally, G. chilianensis showed a greater reduction in suitable habitat and greater eastward range shift compared to T. hsutschouensis. These findings provide empirical evidence that accelerated climate change on the QTP has severe consequences for endemic populations with restricted and isolated habitats. This study demonstrates that different plateau fish have similarities and differences in their responses to climate change. Our findings also highlight that the effects of climate change must be incorporated into the integrated conservation plans for fish species on the QTP and its adjacent areas. [ABSTRACT FROM AUTHOR]

Central America contains a rich diversity of freshwater habitats that support more than 600 species of freshwater fishes. However, despite several perceived threats to the integrity of the freshwater habitats throughout the region, a formal analysis of extinction risk for the region's ichthyofauna is lacking. In this manuscript, we report an updated checklist of species and a novel comprehensive assessment of the conservation status of Central American freshwater fishes by applying the IUCN Red List Categories and Criteria to species at the global level. We also analyze the distribution of freshwater fishes across Central America and generate baseline geospatial data that can be used in multi-species conservation planning processes, which is available through the Red List Website. Our results indicate that between 15 and 28% of freshwater fishes in the region are threatened with extinction, with considerable uncertainty resulting from elevated data deficiency. We identify major and widespread threats in the region, including pollution, agriculture, aquaculture, biological resource use, natural system modifications, invasive species, and land development. This analysis represents an important first step in formulating effective conservation planning and action initiatives for a taxonomic group that historically has received few protections and can be used to inform conservation priorities of freshwater ecosystems at both national and regional scales. [ABSTRACT FROM AUTHOR]

This paper attempts to review the methods and experiences in preserving and restoring grayling stocks in water bodies, which this species currently inhabits or previously inhabited. The study includes a retrospective analysis of the status of grayling populations in their natural conditions as well as a review of current ecological and anthropogenic factors negatively impacting the survival and reproduction of the European grayling in Carpathians. The review includes both foreign and Ukrainian experiences in the creation of broodstocks, which could be used to restore grayling populations in Ukrainian waters in the future. We discuss the use of molecular methods for controlling and maintaining the optimal state of European grayling broodstocks at fish hatcheries as well as their application in supporting river restocking efforts to restore ichthyosis is also discussed. We highlight the state and contemporary problems for the existence of the European grayling in Ukraine. The review presents fundamental approaches using aquaculture and molecular methods that can be employed to address ongoing tasks and challenges in grayling stock recovery. [ABSTRACT FROM AUTHOR]

The distribution of aquatic species results from the complex interplay of biotic and abiotic variables, anthropogenic impacts, and scale effects. Using the results of a large-scale fish monitoring survey, we fitted a spatially-explicit Bayesian model to compare a series of a priori models for predicting the occurrence of the Spirlin (Alburnoides bipunctatus), a small freshwater cyprinid fish of conservation concern. The best-fitting model identified an important effect of river basin, flow disruption, and the number of other fish taxa as predictors. Among major river basins, sampling locations in the Vistula Basin were the most likely to support Spirlin, a possible outcome of postglacial colonisation events and less anthropogenic habitat change. The negative association between flow disruption, comprising engineering schemes for flow regulation, river fragmentation caused by obstacles such as dams, and changes to flow due to water abstraction, reflected the Spirlin's requirements for relatively pristine ecological conditions, including flow heterogeneity and access to coarse substrates for spawning. Similarly, a positive association between the occurrence of Spirlin and fish species richness demonstrates the association of this species with aquatic habitats of high ecological integrity. These findings implicate river fragmentation and changes to flow regime as predictors of river habitat integrity and lend support to the proposition that the Spirlin can function as an indicator species for the monitoring and maintenance of the ecological health of river habitats across Europe. Model predictions also point towards the removal of measures that disrupt river flow, combined with restoration of a coarse benthic substrate, as approaches to mitigate declines in populations of Spirlin across Europe. • National monitoring programmes can shed light on species distributions. • Using a Bayesian approach, we modelled the occurrence of the endangered spirlin. • Spirlin proved to be a sensitive indicator of human-mediated disturbance to rivers. • Supporting heterogeneous river environments represents a key management goal. [ABSTRACT FROM AUTHOR]

This study aims to analyze changes in artisanal fishing perceived by fishers based on their local ecological knowledge, highlighting changes in species availability over time on the coast of Paraíba, in Northeast Brazil. Through data collection from fishers, it was observed that 78.88 % of them noticed changes in fishing activity over time, with a greater perception of changes among groups of more experienced fishers, reaching 93.42 %. The regression analysis applied to the study revealed that the increase in fishing experience is related to the perception of changes that have occurred, suggesting an increase of 5.5 % in the perception of changes for each additional year of experience. The main factors cited for these changes include over-exploitation and environmental degradation. The following most affected species stand out: Mutton snapper (Lutjanus analis), Serra Spanish mackerel (Scomberomorus spp), Quenn triggerfish (Balistes spp) and groupers (Mycteroperca spp), indicating a significant reduction in their catches over the years. Therefore, this study highlights the importance of integrating local ecological knowledge into public policies, not only aiming at the management and conservation of fish fauna, but also at maintaining communities which depend on fishing for their subsistence. This would include more adaptive fishing regulations and fish stock recovery initiatives which are culturally acceptable and ecologically sustainable. • Local Ecological Knowledge of artisanal fishers reflects social interaction, experience and shared knowledge about resources. • The Shifting Baseline Syndrome is a social phenomenon reflecting differing perceptions of environmental and resource changes. • Different perceptions shape local knowledge across fisher generations, aiding management and conservation plans. [ABSTRACT FROM AUTHOR]

The present study demonstrates the spatial analysis and mapping of fish and different measures of environmental parameters and fish diversity of Pong reservoir, Himachal Pradesh, using Kriging spatial interpolation methods for geographical information system mapping. Seasonal data on environmental parameters, potential fish habitat and fish diversity was collected from lentic (dam), lentic (reservoir), transitional and lotic zone of the reservoir.. Important environmental parameters like water temperature, dissolved oxygen, electrical conductivity, water depth and transparency showed variations across the different zones of the reservoir. The sediment of the reservoir was sandy clay loam in nature as per texture analysis. Fish species richness, Shannon index and evenness index showed a similarity of the lotic and lentic (reservoir) zones of the reservoir. Six potential fish breeding grounds were identified in the reservoir indicating high conservation significance. The analysis of data showed a declining trend in fish production from 456.9 tonnes during the decade 1976–1987 to 347.91 tonnes during 2009–2020. The factors like anthropogenic climate change, predation of a stocked fish juvenile by water birds, undersized fish stocking and unscientific management are the probable reasons for the decreasing fish production. The spatial variation pattern of the water spread area, environmental parameters, fish catch and potential fish breeding grounds depicted in the GIS platform can be used as an important information base by the policy makers for fisheries management. The stocking of large size fish as a stocking material and adequate protection of the potential fish breeding grounds are the key advisories for the sustainable enhancement of fisheries as well as conservation. [ABSTRACT FROM AUTHOR]

Actinopyga echinites are among the commercially exploited sea cucumbers; however, limited studies hinder the management interventions for the sustainability of the resource. This study investigates the density and size distribution of A. echinites populations in Cabgan Island, Barobo, Surigao del Sur from March-August 2021 with two stations (shallow seagrass beds as Station 1 and algal flats as Station 2) having three plots (100 m²) laid as monitoring stations. The results revealed the population density of A. echinites ranged from 567-2,567 ind/ha with a mean of 1,572 ± 225 ind/ha in Station 1 and 733-2,400 ind/ha and a mean of 1,389 ± 178 ind/ha in Station 2. Significant differences were only observed across months in each station (P = 0.00) and their interaction between months and stations (P = 0.01). A. echinites had a mean length of 7.58 ± 0.26 cm and weight of 31.39 ± 1.62 g for Station 1 and 7.84 ± 0.47 cm and 39.01 ± 3.91 g for Station 2. Specimens in Station 2 had a greater length and significantly heavier weight than in Station 1 (P = 0.00). Across months, significant differences were recorded for the specimen's length in Station 1 and weight for both stations. The length of A. echinites ranged from 4-12 cm and 4-13.5 cm in Stations 1 and 2, respectively, and weight of 5-129 g in both stations. The highest frequencies were recorded at 7 cm in both stations and shifted to 9 cm. Weight distributions showed the highest frequencies in 35 g in the two stations. The present study shows that the population is still abundant and is more influenced by the sampling months than the stations. The species are smaller compared to other studies and might exhibit habitat preferences. Weight size distribution varied across months and could be related to their reproduction. The study provides significant insights needed for this species' conservation and fishery management. [ABSTRACT FROM AUTHOR]

This research was conducted to explore the status of fish species diversity and production in the Kawadighi Haor of northeastern Bangladesh. Data were collected biweekly through direct catch assessment surveys, focus group discussions, and personal interviews using a questionnaire. A total of 87 fish and prawn species belonging 14 orders and 30 families were identified in the Haor, where 18% species were abundantly available, 20% were commonly available, 42% were moderately available and 20% were rarely available. Among the recorded species, Cypriniformes, having 34 species, had the most species, followed by Siluriformes (20), Anabantiformes (11), Ovalentaria (4), Synbranchiformes (4), Clupeiformes (3), Decapoda (3), Osteoglossiformes (2), Anguilliformes (1), Beloniformes (1), Cyprinodontiformes (1), Gobiiformes (1), Mugiliformes (1), and Tetraodontiformes (1). The values of Shannon-Weaver diversity (H), Margalef’s richness (d), and Pielou’s evenness (J) indices were 2.98, 7.72 and 0.67 in Hawagulaia, 2.97, 7.52 and 0.67 in Patasingra and 2.61, 7.30 and 0.59 in Salkatua beel, respectively. The haor's average yearly fish production was 704.09 kg/ha. Small indigenous species (SIS) of fish dominated the haor's total production, accounting for 51.8 to 70.57 percent of the total contribution. The highest portion of fish produced in the non-stocked beel was SIS of fish but per hectare SIS of fish production of non-stocked beel was lower than the fingerling stocked beels. Aquaculture might have a good effect on fish production and biodiversity. The findings showed that Kawadighi Haor is a very productive and biodiversity-rich inland open waterbody that may function as a mother fishery. For the protection of current fisheries resources, multiple approaches including public awareness campaigns might be beneficial. [ABSTRACT FROM AUTHOR]

The queen conch (Aliger gigas) is a culturally and economically important molluskan fishery resource in the Caribbean region showing increasing signs of over harvest. Shallow-water distribution and large size facilitate capture, and internal fertilization and density-dependent reproduction make managing for reproductive biology critical to stock rehabilitation. In fact, the natural lifetime fecundity of conch is very high but most fisheries in the region harvest conch before even a small fraction of that reproductive potential can be attained. The goal of this review is to provide an up-to-date synthesis of the vast research literature on queen conch biology (spanning >60 years) and to discuss how knowledge of reproduction in conch can help to guide field surveys, fishery management decisions, and stock recovery projects. The review covers the subjects of anatomy, maturation and fecundity as they relate to conch age and size, reproductive behavior including migrations, seasonality, mating, and egg-laying, and the influences of both environmental and demographic variables on reproductive potential. Successes and failures under different forms of management practice are discussed as they relate to reproductive biology and recommendations are made for future research and fishery management alternatives. Successful management will require multiple regulatory approaches. [ABSTRACT FROM AUTHOR]

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The geographic information systems (GIS) play an important role in all geospatial aspects of assessment, monitoring, and management of inland open water resources for strategic development in the fisheries sector. In India, reservoir fisheries development is one of the flagship programme and several initiatives have been taken up towards enhancement and sustainable development. The present study investigates spatio-temporal changes in ecology and fisheries in Hirakud reservoir, Odisha, build across river Mahanadi which features one of the largest dams in South Asia during 2016–17 to 2018–19. The reservoir is mainly utilized for electricity generation, irrigation and offers tremendous scope to support fisheries and livelihood. The mean water spread area during 2016–17 to 2018–19 was at the minimum (42721 ha) during premonsoon period and was at the maximum (62059 ha) during monsoon. Most of the water quality parameters including nitrate, BOD, and alkalinity during 2016–17 to 2018–19 were higher in the premonsoon period and overall, the parameters were under favorable range for fisheries. The present investigation from the fish landing sites of the reservoir, recorded merely 40 fish species, indicating loss of fish diversity as compared to the historical reports. The IUCN conservation status showed that among the 40 species only one species, Wallago attu is under the VU category and 4 species Chitala chitala, Ompok bimaculatus, Ailia colia, and Bagarius bagarius are under the NT category. The fish production in the reservoir was 8200 t during 2018–19. The analysis of time series annual fish catch data using the ARIMA model forecasted the increasing trend of fish production. The water quality parameters were presented in the GIS platform for a better understanding of the spatial variations over time. Habitat protection of fish breeding grounds, closed seasons, mesh size regulations, scientific management, and community participation are recommended as the measures for conservation of fish diversity and sustainable enhancement of fish production in the reservoir. [ABSTRACT FROM AUTHOR]

There are very little data on Central America and the Western Caribbean elasmobranch populations. Here we present the first results of standardized fisheries-independent monitoring of sharks and rays in Panama's Bocas del Toro Archipelago over four consecutive years. Using baited remote underwater videos (BRUVs), underwater visual census (UVC), and scientific longline, we provide baseline data on the composition, relative abundance, distribution, and demographics of seven shark species and six rays observed during the study. Observations differed among methods and habitats, with BRUVs (n = 148) more effective for assessing shark diversity and abundance and UVC (n = 108) more effective for assessing ray abundance. Nurse sharks (Ginglymostoma cirratum) and southern stingrays (Hypanus americanus) were the most commonly observed species overall (frequency of occurrence = 30.4 and 18.9%, respectively). Depth, temperature, and protected area status significantly affected the relative abundance of sharks and rays based on UVC and BRUV data. The use of scientific longlines (n = 55) highlighted the lagoon habitat as a potential nursery site for blacktip sharks (Carcharhinus limbatus), with juvenile (average total length = 113 cm) individuals representing 58% of longline captures. The results provide a current baseline for elasmobranch communities that can further aid in the conservation and management of these species nationally and regionally. [ABSTRACT FROM AUTHOR]