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ABSTRACT Aim Location Taxon Methods Results Main Conclusions The goal of our study was to use a nested sampling design to compare the distribution of different groups of organisms with different dispersal modes and examine their responses in community composition to environmental heterogeneity at different spatial scales (local pool vs. riffle habitat, sections within a river and between rivers).Upper Colorado River basin, Texas, USA.Fishes, mussels and macroinvertebrates.We sampled 100 sites using a nested sampling design across five rivers (four tributaries and the mainstem), with four river sections and five sampling sites per section, each consisting of a pool and riffle habitat. Collected data on species abundances, local and landscape environmental variables and spatial variables were analysed using a combination of dissimilarity, redundancy and variation partitioning analysis.At the river scale, environmental heterogeneity explained 28% and 34% of the variation in mussel and fish communities, respectively, and 15% for macroinvertebrates. Community changes between sections in the tributaries were highest for fishes, but similarly high for fishes and macroinvertebrates in the mainstem. Significant patterns for mussels were only detected in rivers with higher abundances. No significant differences in dissimilarity were found between mesohabitats, but a small significant effect of mesohabitat was detected for mussels with RDA after removing the river effect.Although the depauperate mussel communities made it more difficult to draw any conclusions, there were some indications that their distribution was driven by environmental heterogeneity across scales. Section and river scales were relevant for fish, whereas macroinvertebrates showed a weaker response to environmental heterogeneity at these scales. The combination of approaches detected more ecologically meaningful patterns than one analysis alone would have. This study highlights the complexity of riverine community dynamics and underscores the need for a multiscale approach to identify their distribution patterns. [ABSTRACT FROM AUTHOR]

The operating efficiency of fishermen's associations is significant for developing the fishery industry and fishing villages. Since fishermen's associations have economic, financial, and service sectors, this study evaluates their efficiency through multiactivity data envelopment analysis. In addition to exploring the overall efficiency of each fishermen association, this study further investigates the differences in the operating efficiency of each of the economic, financial, and service sectors. Fishermen's associations were divided according to their sizes and geographic areas for analyses and comparisons by considering the differences in their organizational scales and fishing activities. In the empirical study, 24 fishermen associations in Taiwan were selected as the research subjects, and the shared inputs of economic, financial, and service sectors were taken to conform to their practical operation. The overall efficiency of fishermen's associations was affected by their size and mainly varied by economic sector. The research results indicate room for improvement in the overall efficiency of fishermen's associations, but improving the efficiency of different fishermen's associations should occur in various sectors. [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 Location Methods Results Main Conclusions The assembly of real‐world ecological communities in human‐modified landscapes is influenced by a complex interplay of spatial, temporal, environmental and invasion gradients. However, understanding the relative importance of these drivers and their interactions in shaping functional assembly remains elusive. Our study aimed to investigate the relative influence of these drivers on the functional assembly of a stream fish metacommunity.Streams of the Lake Balaton catchment, Hungary.We analysed a long‐term (18‐year) dataset of the stream fish metacommunity, focusing on changes in functional diversity (Q), redundancy (R) and species dominance (D). Ternary diagrams were utilized to decompose functional diversity into Q, R and D components and to visualize diversity patterns. Linear mixed‐effect regression and separate structural equation models were employed to identify significant drivers of Q, R and D.Native fish communities exhibited low functional diversity (Q) but high redundancy (R) and dominance (D), indicating functional convergence and dominance. Stream habitat size, network position and associated spatial, physical and chemical gradients emerged as consistently significant drivers of D and R. Changes in Q were additionally linked to non‐native community properties and subtle shifts in land use and within‐stream habitat characteristics.Our findings suggest that both environmental filtering and interspecies interactions, particularly trait similarity between invaders and natives shape functional assembly of stream fish metacommunities. Despite minimal temporal directional changes, environmental drivers predominantly influence long‐term diversity patterns of native fish communities, overshadowing invasion effects. Our findings underscore the importance of considering both environmental filtering mechanisms and interspecies interactions in understanding functional assembly. Additionally, the joint application of diversity decomposition frameworks with predictive modelling provides comprehensive insight into patterns of functional diversity and assembly across ecological communities. [ABSTRACT FROM AUTHOR]

This study examines the role of communities, local institutions, conservation organizations and government agencies in the governance of large-scale common-pool resources (CPR) at the Gulf of Mottama Ramsar wetland, Myanmar before and one year after the 2021 coup d'état. The research employed a mixed method approach in two villages in the GOM on common alluvial land, waterbirds, and fisheries CPRs. The robustness of CPR governance is evaluated with Ostrom's eight design principles. We found that pre-coup the formation of local user associations, livelihood incentive strategies, and co-management approaches were increasingly effective to conserve fisheries and waterbirds CPRs, while land conflicts over new common alluvial land persisted. One year following the coup, offshore fisheries especially faced challenges from illegal practices by outsiders, due to significantly weakened co-management practices and accountability of local authorities and large-scale commercial fishers to the fishing communities. [ABSTRACT FROM AUTHOR]

Climate change significantly impacts marine ecosystems worldwide, leading to alterations in the composition and structure of marine communities. In this study, we aim to explore the effects of temperature on demersal fish communities in the Central Mediterranean Sea, using data collected from a standardized monitoring program over 23 years. Computationally efficient Bayesian inference is performed using the integrated nested Laplace approximation and the stochastic partial differential equation approach to model the spatial and temporal dynamics of the fish communities. We focused on the mean temperature of the catch (MTC) as an indicator of the response of fish communities to changes in temperature. Our results showed that MTC decreased significantly with increasing depth, indicating that deeper fish communities may be composed of colder affinity species, more vulnerable to future warming. We also found that MTC had a step-wise rather than linear increase with increasing water temperature, suggesting that fish communities may be able to adapt to gradual changes in temperature up to a certain threshold before undergoing abrupt changes. Our findings highlight the importance of considering the non-linear dynamics of fish communities when assessing the impacts of temperature on marine ecosystems and provide important insights into the potential impacts of climate change on demersal fish communities in the Central Mediterranean Sea. [ABSTRACT FROM AUTHOR]

To enhance management of aquatic systems, long‐term monitoring programs are crucial. However, managers often lack sufficient guidance in decision‐making. In this study, we analyzed nearshore electrofishing data from Lake Ontario spanning 18 years and over 100,000 caught fish to assess sampling designs for various coastal habitats. Using simulation, we evaluated precision of catch per unit effort (CPUE) for all species, piscivores, and specialist species, at different levels of electrofishing sampling effort. For overall CPUE in any habitat type, increased precision declined with additional electrofishing runs, particularly after reaching 30–40 runs. Adjustments in sampling effort, such as adding 10 runs per year for open‐coast sites, increased precision of overall CPUE by 10%. Adding 8 runs per year for wetlands increased precision of specialist‐species CPUE by 10%. However, additional runs in embayments did not increase precision for all species, piscivores, or specialist species. Our findings underscore the importance of considering community composition and abundance when evaluating CPUE precision and illustrates a flexible approach to optimize sampling effort in aquatic monitoring programs. [ABSTRACT FROM AUTHOR]

Nutrient enrichment and climate warming threaten freshwater systems. Metabolic theory and the paradox of enrichment predict that both stressors independently can lead to simpler food‐webs having fewer nodes, shorter food‐chains and lower connectance, but cancel each other's effects when simultaneously present. Yet, these theoretical predictions remain untested in complex natural systems. We inferred the food‐web structure of 256 lakes and 373 streams from standardized fish community samplings in France. Contrary to theoretical predictions, we found that warming shortens fish food‐chain length and that this effect was magnified in enriched streams and lakes. Additionally, lakes experiencing enrichment exhibit lower connectance in their fish food‐webs. Our study suggests that warming and enrichment interact to magnify food‐web simplification in nature, raising further concerns about the fate of freshwater systems as climate change effects will dramatically increase in the coming decades. [ABSTRACT FROM AUTHOR]

Instream wood is important for fish in headwater streams because it promotes the development of pool habitat and provides cover from predators during periods of low flow. The benefits of large instream wood (length > 1 m and diameter > 0.1 m) have been extensively documented, but little is known about the influence of small instream wood (length ≤ 1 m or diameter ≤ 0.1 m) on fish communities and hydraulic conditions (i.e., water depth, water velocity, wetted width, discharge, pool area) in channelized agricultural headwater streams in North America and Europe. Understanding the influence of small instream wood will provide information that can guide the development of novel management strategies for fishes within these degraded streams. We conducted a two-part field experiment in the summer of 2011 in channelized agricultural headwater streams in central Ohio, consisting of an initial instream wood survey to document the amounts and types of instream wood found in these streams, and then conducted a before–after–control–impact experiment where we sampled fishes and hydraulic variables before and after the addition of small instream wood to pools. The instream wood survey documented that instream wood density ranged from 0 to 0.29 pieces/m2, small simple pieces were the most frequently occurring type of instream wood, and parallel was the most frequently occurring instream wood orientation. The amount of instream wood was greater (p < 0.05) in the treatment pools than the control pools after the small instream wood addition. No differences (p > 0.450) in fish community structure or hydraulic variables occurred between control and treatment pools before or after the addition of small instream wood. Our results suggest the addition of large instream wood might be needed to elicit a fish community response, and it is possible to add instream wood to channelized agricultural headwater streams without impeding the downstream water flow. [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]

This study aims to evaluate the efficiency of electric fishing and seine-net/dip-net to obtain quantitative and qualitative data on the fish community of low conductivity streams in the semi-arid region of Bahia, Brazil. Samplings were collected in 15 streams in the region of Chapada Diamantina. Two homogeneous stretches with 50 m each were selected and closed with blocking nets. Zippin analysis was used to evaluate the suitability of each capture method. Differences in abundance, richness, composition of species, and length of specimens captured were compared for each method. Twenty-nine species were collected, twenty-four using electric fishing, and twenty-one using seine-net/dip-net. There were no significant differences between methods as for abundance, richness, composition of species, and length of the individual captured. There were no significant differences in capturability. Both methods have high values of sample efficiency (SE). Therefore, electric fishing and seine-net/dip-net are equally effective on describing qualitatively and quantitatively the fish community. It is noteworthy that for an ideal choice of collection method, the geomorphological characteristics of the streams must be taken into account since they exert a direct influence on both collection methods. [ABSTRACT FROM AUTHOR]

Throughout history, small village communities in the Arctic have developed several strategies to ensure their survival. Along the Torne River, some fishing communities have produced specific architectures, landscapes, and social strategies to support their communities and survive for centuries. However, depopulation, aging, climate change, and the expansion of the extraction industry are threatening these villages. The hypothesis is that traditional fishing villages situated alongside rivers possess architectural, urban, and social attributes that can enhance outdoor activities linked to water and green spaces and enable the long-term social sustainability of Arctic villages. The innovative approach of the paper involves combining a mapping methodology of green and blue infrastructure with the architectural, urban, social and historical values of a place to identify design strategies for improving attractiveness demonstrating its efficacy, particularly in small, local-scale villages. The paper investigates the villages of Kukkola and Korpikylä taken as emblematic examples and explores the architectural and landscape value in relation to the green–blue infrastructure. [ABSTRACT FROM AUTHOR]

Changing nutrient concentrations and introduction of non-native species affect the energy and nutrient fluxes in aquatic ecosystems. As a response, invertebrate communities could be altered, and 'novel' trophic communities could develop. Lake Constance (Europe) experienced pronounced nutrient variation caused by cultural eutrophication (prior 1980s) and oligotrophication (post-1980) and experienced many neobiota invasions. We used archived samples to investigate the impact of oligotrophication and invasive species on carbon and nitrogen isotope signatures of littoral macroinvertebrates during spring and autumn periods from 2000 to 2015 and of littoral fish species in 2018. Isotopic signatures of invertebrate and fish species were in the same range and showed similar seasonal differences and clear patterns in respect to littoral vs pelagic food sources and trophic level. Oligotrophication did not strongly alter isotopic values and only δ15N values of invertebrates declined weakly with oligotrophication. In contrast, interannual variability of stable isotope signatures was related to abundances of the invasive Dreissena polymorpha suggesting interannual differences in the importance of benthic-pelagic coupling due to Dreissena pseudofaeces for the nutrition of littoral invertebrates. This study illustrates how stored samples can be used to detect the importance of oligotrophication and benthic-pelagic coupling on the stable isotope signatures of a benthic community. [ABSTRACT FROM AUTHOR]

Water diversion for hydropower plants is one of the leading causes of habitat alteration and biotic homogenization. The impacts of small hydropower plants on fish communities are usually assessed using taxonomic composition and structure indicators. Size-based indicators are useful tools to evaluate the effects of environmental factors and anthropogenic perturbations on riverine ecosystems. In this study, we investigated the impact of water diversion on fish community body size structure in 16 small hydropower plants in the upper Ter River basin (NE Iberian Peninsula). We tested the use of multiple size-based metrics under different sampling intensities (one- vs. four-pass electrofishing) and compared control vs. diverted stream stretches. Results revealed that water diversion had a negative effect on fish community average and median length, while size spectrum and size diversity metrics showed no responses to the impact. Altitude was positively related with body size metrics and was the strongest natural driver affecting them. Moreover, we found that all the size-based metrics exhibited consistent values under different sampling efforts. Our findings suggest that size-based metrics could be useful indicators for bioassessment of river flow alteration and that one-pass electrofishing was robust enough to characterize the stream fish community size structure in our study. [ABSTRACT FROM AUTHOR]

Freshwater biodiversity is rapidly declining worldwide, especially in tropical island environments which appear to be particularly vulnerable to alien species. Monitoring biodiversity using effective methods is crucial for conservation efforts. This study aims to examine the capacity of the eDNA-based method to provide accurate measures of fish and crustacean biodiversity, and how it can be implemented in the French West Indies. To this end, we conducted eDNA and electric fishing capture-based surveys in parallel, both upstream and downstream, in nine Guadeloupean rivers and during two different seasons. While both methods were congruent in terms of species richness and composition, the eDNA-based method generally exhibited greater efficacy and reliability in assessing biodiversity. The exception to this trend was observed during the second campaign for the crustacean community. The quantitative data (the numbers of individuals and percentages of sequences) also proved to be uncorrelated for crustaceans during the second campaign, indicating that further knowledge of crustacean biology is needed. Nevertheless, the eDNA-based method was able to detect the presence of alien, rare and cryptic species, showing that it can be used in tropical island conditions for biodiversity assessment or conservation purposes. [ABSTRACT FROM AUTHOR]

In a commercial fishery, some fish are classified as low-value, but their classification varies in different countries. The aim of this study was to determine the abundance, contribution, and dominance of low-value fish species, such as Abramis brama < 1000 g, Alburnus alburnus, Blicca bjoerkna, Gymnocephalus cernua, Perca fluviatilis < 100 g, Rutilus rutilus < 200 g, and Scardinius erythrophthalmus < 200 g, in 145 Polish lakes of different areas, depths, and trophic statuses situated in the northern and central parts of Poland in 2021. Perca fluviatilis and R. rutilus were the most frequent low-value species (100% and 99%, respectively). The contribution of all low-value fish to the total biomass of caught fish was relatively high, ranging from 37% in the mesotrophic lake to 100% in the eutrophic lake (mean of 77 ± 14%). Lakes in which the contribution of low-value species exceeded 90% were relatively numerous (24 lakes, 17% of the studied lakes). Among a total of about 437.5 thousand low-value fish, 261 thousand specimens (60%) had a body weight of below 10 g. All low-value fish species, except for P. fluviatilis and S. erythrophthalmus, were related to the studied environmental variables. The relative biomass of these species increased with increasing lake productivity, while it decreased with the increasing maximum and mean depth of the studied lakes. The high contribution of low-value fish to the total biomass in many lakes indicates the need for the constant monitoring of the abundance and structure of fish communities and the use of appropriate actions (biomanipulation and stocking with piscivorous fish species) to improve the ecological condition of lakes. [ABSTRACT FROM AUTHOR]

Urban river restoration efforts are growing worldwide. Along with restoring and conserving rivers, riverside land is slated for public recreation, property development, and infrastructure for adaptation to climate change. Riverine landscapes, embedded in larger watershed ecosystems and claimed by multiple communities, are sites of contested planning in contemporary cities. In this paper, we advance the scholarship on contestation over control and access of urban rivers and floodplains by analyzing the role of river restorative legislation and water-centered planning in managing Turag, an urban river in Bangladesh. While river degradation in urbanizing regions is often ascribed to lack of regulatory controls and enforcement, we argue that restorative legislation and interventions facilitate Turag River's ecocide by processes of territorialization. Territorialization refers to the co-constitutive dynamics of river restorative legislations and interventions as well as planned infrastructure and land use changes, which erase and displace river-based communities with reciprocal relations to the river. Riverine livelihoods and lifemaking, among fishing and farming communities in the case of Turag, are erased from planning and restoration practices, and are consequently expelled from the expanding city. Drawing on qualitative and counter-cartographic investigation of one severely polluted urban river in Dhaka, Bangladesh, we show how territorialization materializes through five co-constitutive dynamics involving environmental legislation, encroachment reporting, river demarcation, encroachment evictions, and wetland to land conversions. We draw out critical implications of how river restoration can be just and advance a riverine urbanism. [ABSTRACT FROM AUTHOR]

Recruitment is the addition of individuals to a population that generally occurs in the early juvenile phase, which is key to understanding the dynamics of reef fish communities. Through visual censuses in three climatic seasons (dry, rainy, and northerly winds) between 2017 and 2020, the analysis of seasonal and interannual variations in the abundance of fish recruits in a reef lagoon (Mahahual, Quintana Roo, México) was carried out. Temporality was analyzed using average recruit density graphs and multivariate analyses (multivariate ANOVA, ANOSIM, and RDA) to assess composition differences between year and season levels. A total of 9326 recruits were registered, belonging to 36 species and 8 fish families. The Labridae had the greatest number of recruits, followed by Pomacentridae and Scaridae. The recruits were more abundant in the dry season when the average temperatures were 27.50–27.87 °C; meanwhile, they presented a lower abundance in the northerly wind season when the temperature was lower (26.7 °C). The most abundant species was Thalassoma bifasciatum (138.72 recruits/100 m2), followed by Abudefduf saxatilis (100.05 recruits/100 m2) and Halichoeres bivittatus (45.94 recruits/100 m2). The multifactorial ANOVA for the average density and the ANOSIM for the composition of recruits did not show significant differences for the year factor, but they did for the season factor. RDA indicated that the greatest average dissimilarity existed between the dry season and the other two climatic seasons. The results of this study highlight the importance of recruitment during the warm months and the refuge offered by the lagoon for the maintenance of reef fish populations. [ABSTRACT FROM AUTHOR]

The ability to strengthen governance institutions and fisheries restrictions and laws is needed to improve conservation and management of common‐pool resources. We evaluated the potential for stimulating change with modest interventions by studying fishing village households before and after a 27‐month intervention period in a high‐priority coral reef conservation area. Interventions included training in catch monitoring, stock assessment, mapping fishing grounds, microcredit, gender inclusion, theatrical skills, fuel efficient stoves, and participation in the planning of a conservation proposal. There was a background increase in reported formal education, household size, group membership, and household wealth but a decrease in fish consumption and public services. Of conservation importance, the perceived strength of 13 governance institutions and benefits of 6 fisheries restrictions increased over the intervention period. Finally, correspondence between knowledge of and agreement with recent national fisheries laws was moderate to high and positively correlated. The intervention period was stronger than demographic factors that often influence perceptions, such as village, government services, gender, household size, membership in community groups, and age responses. In general, perceptions of strengths of governance and benefits of restrictions increased more among women and youth than adult men respondents. The largest changes in perceptions of increased benefits were among strict restrictions initially ranked low, specifically fisheries closures, parks, and species restrictions. Consequently, capacity building overrode demographic factors common to poor people with limited employment capacity that can have negative perceptions of strict conservation. [ABSTRACT FROM AUTHOR]

The implementation of the rural revitalization strategy focuses on the prosperity of industries, and the effective combination of industry, academia, and research is an effective means and important measure to promote the high-quality development of digital fisheries. By sorting out the policy environment for the high-quality development of central and local fisheries under the current background of rural revitalization, taking Taizhou City as an example, this paper summarizes and analyzes the current situation of fisheries and digital fisheries development, and introduces typical models of industry academia research to assist in the high-quality development of digital fisheries. This paper provides a certain reference for the construction of modern and beautiful fishing villages under the background of rural revitalization. [ABSTRACT FROM AUTHOR]

This study delves into the lives of women from the Koli fishing community in Mumbai, aiming to illuminate their unique life experiences and the daily struggles that often remain hidden beneath their prosperous facade. It endeavours to examine their agency and adaptive strategies employed to navigate these challenges. The research was conducted in Pachubandar, Vasai, located in the western suburbs of Mumbai, which stands as one of the prominent Koli settlements in the city. Employing a qualitative research approach coupled with an exploratory research design, the study engaged ten participants, comprising seven Koli women and three key informants from the community. Additionally, an observational analysis of four retail and wholesale fish markets in Mumbai was conducted to gain insight into the working conditions of Koli fisherwomen.This study adopts a gender-focused perspective to scrutinise the contextual vulnerabilities that shape the lives of Koli women. It underscores the paradox wherein, despite playing a pivotal role in sustaining both their families and the traditional fishing occupation, their contributions often go unnoticed. The Koli women face severe deprivation due to their limited access to property and decision-making authority. They find themselves entangled within traditional norms and patriarchal structures, which impede their access to essential assets and diverse livelihood resources. Although they significantly contribute to the fishery sector, their struggles, needs, and aspirations are frequently disregarded due to their lack of representation and involvement in decision-making bodies. The majority of these women work under precarious conditions, devoid of proper infrastructure, resources, and security. Furthermore, the evolving dynamics within the fishery sector, driven by rapid urbanisation and modernisation, have a profound impact on the lives and traditional livelihoods of Koli women. They now confront issues such as dwindling fish catches due to environmental degradation, heightened market competition, reduced livelihood spaces brought about by shifting urban and coastal landscapes, altered labour relations, and technological advancements. Consequently, they find themselves caught between the conflicting forces of tradition and modernity. The research also sheds light on the strategies devised by Koli women to resist and adapt to the uncertainties and challenges they encounter, ultimately safeguarding their livelihoods through self-organisation. The study emphasises the imperative to acknowledge their contributions as ‘visible work’ and advocates for the incorporation of gender considerations when formulating policies and development strategies within the fisheries sector. [ABSTRACT FROM AUTHOR]

Marine fisheries are increasingly impacted by climate change, affecting species distribution and productivity, and necessitating urgent adaptation efforts. Climate vulnerability assessments (CVA), integrating expert knowledge, are vital for identifying species that could thrive or suffer under changing environmental conditions. This study presents a first CVA for the Western Baltic Sea's fish community, a crucial fishing area for Denmark and Germany. Characterized by a unique mix of marine, brackish, and freshwater species, this coastal ecosystem faces significant changes due to the combined effects of overfishing, eutrophication and climate change. Our CVA involved a qualitative expert scoring of 22 fish species, assessing their sensitivity and exposure to climate change. Our study revealed a dichotomy in climate change vulnerability within the fish community of the Western Baltic Sea because traditional fishing targets cod and herring as well as other species with complex life histories are considered to face increased risks, whereas invasive or better adaptable species might thrive under changing conditions. Our findings hence demonstrate the complex interplay between life-history traits and climate change vulnerability in marine fish communities. Eventually, our study provides critical knowledge for the urgent development of tailored adaptation efforts addressing existing but especially future effects of climate change on fish and fisheries in the Western Baltic Sea, to navigate this endangered fisheries systems into a sustainable future. [ABSTRACT FROM AUTHOR]

The energy transition is Brazil's main policy in the context of adapting to and mitigating climate change, especially through the installation of wind energy projects. However, at the same time, the energy transition is used as a strategy to diversify the investment portfolios of transnational corporations, resulting in territorial impacts for communities located in the vicinity of these energy projects. The objective of this article is to discuss how the energy transition results in territorial impacts on the traditional fishing community of Enxu Queimado, located in the municipality of Pedra Grande, on the coast of the state of Rio Grande do Norte. To achieve this objective, quantitative and qualitative methodologies were used, including carrying out fieldwork in the community in the year 2023. With the research it is possible to conclude that the energy transition from the centralized energy generation model has been carried out from the violation of territorial rights of traditional communities, configuring the agrarian issue. The question is: energy transition or a new frontier for the expansion of capital? [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]

Chimpanzee insectivory is seasonally variable, with pronounced peaks or set seasonal periods of consumption observed in most chimpanzee communities. This variation is interesting given that chimpanzees invest considerable effort into complex tool‐using behaviors to acquire insect prey. Evidence suggests this seasonal variation is related to insect behavior, but few studies have been done to empirically examine this relationship. In this study, we assessed whether a seasonal pattern of termite fishing by Nigeria‐Cameroon chimpanzees (Pan troglodytes ellioti) in Mbam & Djerem National Park, Cameroon was driven by termite behavior. We measured termite presence and termite foraging activity monthly at seven termite mounds near Ganga Research Station from April 2022 to April 2023. Macroscopic fecal analysis and camera traps placed at each mound demonstrated termite fishing in this community occurred from March to June, with a rare smaller period of termite fishing in October 2021. Average monthly rainfall, average monthly temperature, and average monthly fruit availability were used to examine potential environmental factors that could impact termite fishing seasonality. Termite presence was significantly different between months with and without chimpanzee termite fishing (t‐test, −6.569, p <.001). Termite presence was also significantly associated with average monthly rainfall (ANOVA, F = 13.9, p =.002, R2 =.775). Termites in this region appear to respond to the transition from dry to wet seasons by moving closer to the soil surface. This corresponds with greater chimpanzee termite fishing, suggesting that termite accessibility may be driving seasonal variation in this behavior. [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]

Estuaries are often observed as the boundary between the ocean and the river, separating coastal environments, rather than being seen as a continuum. Owing to insufficient research on demersal fish communities across nearshore marine to estuarine habitats, particularly in South Africa, this study employed a spatial seascape approach, with seasonal sampling of soft-bottom benthic habitats in two permanently open estuaries and the adjacent marine nearshore environment of Algoa Bay on the south coast of South Africa. A total of 790 fish representing 29 species were collected in the marine nearshore, and 6 414 fish (28 species) were caught in the estuarine zone. Two discrete demersal fish assemblages were identified as representing the marine nearshore and estuarine environments. The marine nearshore fish assemblages were dominated by marine species (e.g. Argyrosomus inodorus and Cynoglossus zanzibarensis) that were not recorded in the estuarine environment, whereas marine estuarine-opportunist species (e.g. Pomadasys olivaceus and Galeichthys feliceps) were more abundant in the marine nearshore than in the estuarine environment. The estuaries were dominated by benthic marine estuarine-dependent and marine and estuarine species (e.g. Rhabdosargus holubi, Solea turbynei, Heteromycteris capensis, Psammogobius knysnaensis and Glossogobius callidus). Differences observed in abundance and species richness along the estuarine to marine continuum were primarily related to the salinity gradient. These findings are significant as altered freshwater flows and consequent changes in salinity and productivity can have an impact on the nursery use of both estuaries and the marine nearshore by fish species. [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 few heritage researchers and protection practitioners in some African countries define heritage sites and cultural objects based on European and North American criteria. Such criteria emphasize visual material remains like monumental structures and their aesthetically pleasing features. This Western view overlooks some critical aspects. For example, to local people, the meanings and associated values make the monuments and sites relevant. Despite the inseparability of the tangible heritage and associated intangible aspects such as spiritual practices, some researchers and heritage practitioners, including antiquities department officials, need to pay more attention to the invisible meanings embedded in the sites and cultural objects. Notably, it is these immaterial aspects which the local people value the most. In this article, we survey three fishing villages: Batini, Mkadini and Winde, on the Swahili coast in East Africa, and document what heritage means from the local people's perspective. We argue that fishing communities value features like reef crests, sacred mangrove forests, the ruins of stone-built tombs and sacred baobab trees not because of their physical appearance but the spiritual practices (e.g., healing, rituals, and offerings) the local people undertake within and around these sites. We further contend that to achieve heritage preservation sustainability, government officials and heritage scholars should pay greater attention to the spiritual aspects associated with these places. [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]

In European Union member states, the community‐led local development (CLLD) approach implemented through Fisheries Local Action Groups (FLAGs) represents different social organisational and democratic traditions. Hence, FLAGs operate and apply local development strategies and strengthen the role of fishing communities and the fishing industry under the influence of nationally contingent factors. Based on document analysis and mixed methods data, this article addresses the role of input legitimacy in FLAGs in Denmark and Finland. The findings show that Danish FLAGs demonstrate input legitimacy, while the fishery sector's interests are relatively weakly represented on FLAG boards. In Finland, the FLAG institutional system is perceived to be more flexible, demonstrating a lower level of input legitimacy, while the fishery sector's interests are substantially represented on FLAG boards. The comparison provides an analytical basis for member states financing CLLD through EMFAF and paves the way for reflexion on the FLAG governance system based on different programming periods and institutional contexts. [ABSTRACT FROM AUTHOR]

This study analyzes the relationship between the fishing community and the sea which is manifested through the ritual of sea alms. The theory used is Bruno Latour's ANT theory which has five concepts, namely actors, networks, actants, translations, and intermediaries. The researcher focuses on the concept of network actors, and translations. The research method used is the descriptive qualitative research method. Data were collected through interviews, observation, and documentation. The informants who were interviewed were fishermen, fishermen's families, traditional leaders (community leaders), and the surrounding community following the sea alms tradition. The results show that the process of the sea alms tradition begins with a procession to the river mouth to bring umborambe (offerings) which are put into julen (miniature joglo houses) containing clothing, goat heads and feet, fruits, and other objects that are considered the favorite of the ruler of the ocean (Nyi Roro Kidul) to be floated to the sea. Bruno Latour's ANT theory explains that there is a relationship between humans and non-humans that influence each other and form a network in the form of sea alms. This tradition brings together humans and non-humans to remain balanced and mutually influential. [ABSTRACT FROM AUTHOR]

Great Lakes coastal wetlands are under considerable stress from numerous anthropogenic threats, including the introduction of invasive species. Common Carp, an invasive species in North America, has been well documented as an influential wetland stressor. This study documents the impact of Common Carp reintroduction on a restored wetland fish community and abiotic and vegetation variables. Oshawa Second Marsh was restored using an exclusion berm with a fish grate and manual water-level drawdown to re-establish vegetation. Five years into restoration monitoring, Common Carp regained access to the wetland after the fish grate was vandalized. Fish community health was monitored over time using multimetric and multivariate approaches based on abiotic and vegetation variables. Improvements in fish community health were observed during restoration monitoring, but after Common Carp reintroduction, fish community health decreased and the community homogenized. Seven of the ten abiotic and vegetation variables monitored changed significantly after Common Carp reintroduction. This study highlights the impact that Common Carp has on the functional integrity of coastal wetlands and the significance of its management for restoration. [ABSTRACT FROM AUTHOR]

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Transformations of houses and changes of physical appearances of forms in response to climate is a common phenomenon that happens around the world. In southern Bangladesh, similar transformations take place. However, other autonomous vernacular Transformations are also taking place in post-disaster resettlement housing. This is because the top-down approach to design and implementation of post-disaster resettlement programmes are often influenced by spatial factors such as land availability and access to infrastructure facilities, and fail to recognize the socio-economic and cultural sensitivities of the resettling communities. These transformations indicate a gap between the housing provision process and the needs of the users. They also reflect many unidentified aspects like traditional dwelling patterns, building materials, flexibility, livelihood options, and accommodation of the needs of the future generation, being overlooked. Since these issues are not mutually exclusive from spatial factors, this research develops a framework to assist the design and implementation of migrant resettlement programmes for those affected by disasters through better coordination between spatial factors on the basis of the needs of the people. In Bangladesh, the government-provided rehabilitation housing, like the Ashrayan projects, often experience these physical transformations. The fishing communities find that their traditional lifestyles and the vernacular settlement layouts are often ignored in government housing. This research examines "Nakna Ashrayan Prokolpo-II" as a case study. It employs both qualitative as well as quantitative approaches. Data has been collected through participant observations, Key Informant Interviews (KII) and Focus Group Discussions (FGD). The finding show that the users gradually alter the governmentprovided housing units. Employing a self-help approach without the need for building designs or authorizations, people engage direct labor, use locally available materials, and transform the houses to construct a sense of attachment. The rigid layouts are thus modified to establish a sense of belonging which meet their deep-seated needs which also help the well-being of the families. [ABSTRACT FROM AUTHOR]

Kelp forests provide habitat for many species, but it remains uncertain whether specific kelp forest types support distinct biodiversity. Surface canopy-forming giant kelp (Macrocystis pyrifera) forests in Tasmania, Australia, have declined significantly due to climate change, and have been widely replaced by forests dominated by smaller stipitate kelps like Ecklonia radiata. However, there is limited knowledge of the community composition of Macrocystis forests and how this may differ from the stipitate kelp forest community. Underwater visual census surveys were conducted of the fishes and macroinvertebrates (> 2.5 cm length) in remnant Macrocystis forests in south-eastern Tasmania, and in adjacent stipitate kelp forests. 18 sites (9 of each forest type) were surveyed across two regions during the period of peak growth and canopy cover (i.e. winter-spring). Faunal community composition varied little between forest types, although Macrocystis forests supported more than double the abundance and biomass of mobile fishes, while cryptic fishes differed by forest type depending on region. Macroinvertebrate assemblages did not differ between forest types nor regions. Thus, for the taxa and time period examined, Tasmanian Macrocystis and stipitate kelp forests supported mostly similar faunal communities. Kelp forest communities showed spatial variation and were also likely influenced by a variety of other habitat characteristics, such as the relatively small patch sizes and/or ephemeral state of the remnant Macrocystis forests. Quantifying the community structure of these endangered communities informs the ecological changes that have occurred and will serve as an important reference for ongoing conservation and restoration activities. [ABSTRACT FROM AUTHOR]

Objective - This study was undertaken to analyze the relationship between perceived negative impacts on land reclamation (LR) and support for coastal ecotourism within fishing communities (CE), with environmental awareness (EA) as the mediating variable. Methodology - This study utilized a convenience sampling technique to distribute questionnaires to 400 domestic tourists in coastal areas. Data analysis was conducted using Hayes's PROCESS in IBM Statistical Package for Social Science (SPSS v25.0). Findings - Results showed that LR had a direct effect on CE [ß= 0.183; 95% confidence interval (CI) 0.095-0.270; P= 0.000 <0.05]. Furthermore, a statistically significant indirect effect between LR and CE via EA was also observed (ß= 0.269; 95% CI =0.192-0.351; P= 0.000<0.05), indicating partial mediation. Novelty - These findings highlight that EA is important and essential to be promoted when considering sustainable development in both land reclamation and coastal ecotourism in fishing communities. Affected communities, usually with high environmental awareness, will comprehend the impacts of land developments and react to conserve the environment. In this case, as significant stakeholders with high environmental awareness, tourists are more inclined to support ecotourism, advocate for environmental conservation, and preserve local fishing cultures for appreciation. [ABSTRACT FROM AUTHOR]

Understanding consumer–resource interactions is essential for understanding the trophic dynamics of species-rich fish communities. Woodland et al. (Oikos 125:556–565, 2016) assumed that trophic position (TP) distributions of primary consumers and tertiary species are restricted versus intermediate consumers tending to be omnivores with broader TP distribution, where these omnivores often dominate the overall biomass. With rare evidence supporting this hypothesis in a river, we tested it in the species-rich Pearl River fish assemblage, China. Using bulk stable isotope (SI) approach (δ13C, δ15N), the TPs, SI distribution parameters, isotopic niche sizes (as standard ellipse areas, SEA) and interspecific niche overlap were calculated for the abundant fish species. Fishes of intermediate TPs (i.e. omnivores) had larger δ13C variance/ range, broader isotopic niches and higher niche overlap compared to fishes at low TPs and high TPs, indicating a higher degree of trophic redundancy among the omnivores, whereas high TP fish had narrower niche and lower niche overlap, indicating trophic partitioning among tertiary species. These omnivores at intermediate TPs between 2.4 and 2.8 dominated fish biomass. The results not only support the Woodland et al. (Oikos 125:556–565, 2016) hypothesis in the river, but also provide a novel explaining in how niche sizes and overlap vary by TP. [ABSTRACT FROM AUTHOR]

Fisheries and bottom seawater data were collected in July in 2022 and 2023 from 15 sampling stations in the Huanghe River estuary and adjacent seas in China. The patterns of functional alpha and beta diversity of fish communities in this area and their relationships with environmental factors were studied using trait-based analysis. Five functional classifications, which included 16 functional traits, four functional alpha diversity indices (functional richness, functional evenness, functional divergence, and community-weighted mean), three functional beta diversity indices (functional beta diversity and its turnover and nestedness components), and 14 bottom environmental factors were considered. The dominant traits of fish communities were the following: benthivorous feeding habits, small and front-facing mouths, high trophic level, demersal, anguilliform, low growth coefficient, medium resilience, low vulnerability, and adapted to warm temperate conditions. The dominant migration traits and types of fish eggs varied by year, and fish abundance was the main factor affecting the dominant traits of the communities. The results of multiple regression on distance matrices and variance partitioning analysis indicated that ammonia nitrogen content, total phosphorus content, and pH were the main environmental factors that affected fish functional diversity. The N/P ratio had a bottom-up control effect on fish functional diversity. Our findings also revealed that high pH gradients and distant geographical distances can inhibit trait turnover in fish communities. [ABSTRACT FROM AUTHOR]

The Yellow River Estuary and its adjacent waters serve as crucial spawning, foraging, and nursery areas for marine organisms, possessing abundant biological resources. Monitoring fish communities provides a baseline for implementing the sustainable utilization of marine resources. In this study, data were collected from 15 spring surface and bottom sites and 17 summer surface sites using eDNA and trawl surveys. The results showed that 37, 40, and 35 fish species were detected using eDNA in the spring (surface and bottom) and summer (surface), respectively, with 38 fish species caught during summer trawling. The dominant species mainly belonged to Engraulidae of Clupeiformes in the spring and Gobiidae of Perciformes in the summer, characterized by smaller-sized, short-lived, and pelagic fish species. The summer surface communities exhibited higher diversity than the spring surface and bottom communities. NMDS analysis revealed a degree of seasonal differences in fish communities and that there may be a lack of vertical stratification in the spring communities. The pH and DO were identified as the key environmental factors affecting the fish community. Additionally, the combination of eDNA and trawl surveys was regarded as a superior survey method. Our study provides valuable information for understanding seasonal fish communities in the Yellow River Estuary and its adjacent waters, contributing to fishery resource management and conservation in the region. [ABSTRACT FROM AUTHOR]

Transdisciplinary approaches combining technical perspectives with qualitative insights from the social sciences and non-academic stakeholders have emerged as a promising way to address the complexity of current socioenvironmental crises. However, transdisciplinary incorporation of diverse interests, knowledge, and worldviews requires acknowledging and addressing inherent inequities. Our case study combines two complementary transdisciplinary studies, the first conducted by a biologist/ecologist being trained in inter- and transdisciplinary methods at the time of the study, applying a quick participatory diagnosis in a fishing community, while the second is conducted by a social scientist studying the research group itself. Our results allow an exploration of the challenges and possibilities of navigating from transdisciplinary ideals to practical implementation. Our findings highlight the importance of nurturing relationships built on care, reciprocity, and openness to address the power imbalances inherent in university-community participatory practices. We suggest that the community's autonomy and agency can be preserved while actively engaging its members in the transdisciplinary process, alleviating power differences and fostering a collaborative and equitable transdisciplinary framework. Overall, we emphasize the significance of integrating participatory methods, critical reflexivity, and attention to power dynamics in realizing the potential of transdisciplinary approaches for addressing complex conservation challenges and fostering meaningful community engagement. [ABSTRACT FROM AUTHOR]

The Cosmonaut Sea is one of the least accessed regions in the Southern Ocean, and our knowledge about the fish biodiversity in the region is sparse. In this study, we provided a description of demersal fish diversity in the Cosmonaut Sea by analysing cytochrome oxidase I (COI) barcodes of 98 fish samples that were hauled by trawling during the 37th and 38th Chinese National Antarctic Research Expedition (CHINARE) cruises. Twenty-four species representing 19 genera and 11 families, namely, Artedidraconidae, Bathydraconidae, Bathylagidae, Channichthyidae, Liparidae, Macrouridae, Muraenolepididae, Myctophidae, Nototheniidae, Paralepididae and Zoarcidae, were discriminated and identified, which were largely identical to local fish occurrence records and the general pattern of demersal fish communities at high Antarctic shelf areas. The validity of a barcoding gap failed to be detected and confirmed across all species due to the indicative signals of two potential cryptic species. Nevertheless, DNA barcoding still demonstrated to be a very efficient and sound method for the discrimination and classification of Antarctic fishes. In the future, various sampling strategies that cover all geographic sections and depth strata of the Cosmonaut Sea are encouraged to enhance our understanding of local fish communities, within which DNA barcoding can play an important role in either molecular taxonomy or the establishment of a dedicated local reference database for eDNA metabarcoding analyses. [ABSTRACT FROM AUTHOR]

Climate change and anthropogenic stressors affect the distribution, abundance, and diversity of fish communities across the world. To understand rapidly changing biotic communities, resource managers need a method to quickly and efficiently document temporal and spatial changes in community assemblages across various spatial scales. In this study, we describe the use of new video lander tools to survey fish communities in rocky marine habitats on the continental shelf and slope in California, USA. We evaluate how fish diversity metrics determined by video surveys vary among geographically distinct areas. Our results demonstrate that species diversity, evenness, and richness vary spatially across the coast. Furthermore, community assemblages differ at both broad and fine spatial scales because of differences among habitats. Length frequencies and densities of species in this study were similar to those reported in previous studies. As community assemblages and biodiversity metrics shift in response to changing stressors, it is increasingly important to develop tools and methodologies to detect and rapidly monitor these changes. [ABSTRACT FROM AUTHOR]

Parasites represent a critically understudied component of reef communities—a knowledge gap that has become more evident as infectious diseases emerge. Here, we test the roles of competing ecological and evolutionary factors in driving infections by an emerging infectious phenomenon: Black spot syndrome (BSS) in Caribbean reef fishes. BSS, a condition associated with localized hyperpigmentation in the dermis and fins of fishes, has recently been linked to infection by trematode parasites in the genus Scaphanocephalus. Using phylogenetic generalized linear mixed models, we evaluated the influence of host phylogeny, habitat preference, body size, and trophic position on infection abundance. Metacercariae of Scaphanocephalus were recorded in 29 of 41 fish species, including 21 new host species records, and within 306 fish (62.3% prevalence). Among species, infection load increased significantly with host body size and decreased with host trophic level, such that large-bodied herbivores tended to support the most infection. There was no significant effect of host phylogeny on infection load. These results suggest the parasite is a generalist in its use of fish intermediate hosts and emphasize the influence of local variation in parasite exposure risk. Overall, the count of visible spots per fish was a positive predictor of Scaphanocephalus abundance among species and individuals, although not all fish species exhibited spots, even when infection loads were high. Findings from this study indicate that Scaphanocephalus infections are far more prevalent in reef fishes than previously recognized and highlight the importance of investigating infection patterns beyond the external symptoms of BSS. [ABSTRACT FROM AUTHOR]

Assessments of changes in the ecological state of aquatic ecosystems are always burdened with uncertainty, which results from environmental reasons and poor repeatability of measurement results of elements enabling the assessment. This study determines the uncertainty related to the elements of the assessment of the hydroacoustic structure of fish communities' (1) vertical target strength distribution (TS) in two-meter layers of water and (2) changes in the area where fish were recorded (which was determined on the basis of maps of their distribution in 2 m deep water layers). The object of this study was a lake (depth: 27 m) in which at the end of June 2016 the O2 concentration was <1.4 mg L−1 below 8 m depth, which resulted in the accumulation of fish to a depth of 6 m. Hydroacoustic acquisition was carried out along transects arranged in the east–west (WE), north–south (NS), and zigzag (ZZ) directions in three repetitions. It was shown that the empirical probability of obtaining statistically different results was 2/9 when (1) Kendall's τ coefficient, used to determine the similarity of the TS distribution, was less than 0.7—moderate correlation—and (2) fish occurrence areas in two cases (WE and ZZ on the third day of research) in layers 2–4 m and 4–6 m differed statistically significantly from the average area for all repetitions by 10–14% and 56–66% (p < 0.05), respectively. The obtained results indicate quite good repeatability of acoustic measurements; however, in order to reduce the uncertainty, it is recommended that tests be conducted in this type of lake in three series of measurements. [ABSTRACT FROM AUTHOR]