River Fisheries Research Articles

S-BESE: Strategy for Improving the Quality of Life for Coastal Area Communities in West Kalimantan

The coastal area of West Kalimantan has a wealth of marine and river fishery resources that have the potential to be utilized optimally, including fishing, conservation, port activities, marine cultivation, coastal tourism, and water. Various problems in coastal areas that need to be prioritized to provide solutions include the occurrence of illegal fishing, damage to coral reef ecosystems and mangroves, coastal abrasion, not yet optimal development of ponds where utilization only reaches 40% of their potential, natural disasters which result in increased poverty and ecosystem damage, as well as the growth of corruption and injustice. The number of people living in poverty has been steadily increasing at an average rate of 6.86% over the past three years, reaching 353,350 individuals in 2023. This research aims to develop coastal areas, creating local economic development innovations to reduce poverty, unemployment, and inequality and preserve natural resources. The method developed in this study was carried out descriptively and qualitatively by developing an in-depth analysis through SWOT. The results provide solutions for improvements and innovations, which include implementing a blue economy by utilizing the modernization of fishing gear, developing a paradigm shift from land to water resources, and producing garbage filters in rivers so they do not wash away into the sea. This study will improve the quality of life economically and socially while maintaining the ecology in coastal areas.

Population Responses of Blueback Herring to Dam Passage Standards and Additive Mortality Sources

Abstract The management of anadromous fishes is inherently complicated as this suite of species exhibits complex life-histories in multiple habitats and is subject to varying natural and anthropogenic influences during discrete ontogenetic periods. Life-history based simulation models have been increasingly adopted by fishery scientists and managers to help understand potential effects of management decisions on fish populations while incorporating uncertainty in life-history, climate, and other components of resource management systems. We applied one such model to Blueback Herring Alosa aestivalis in the Hudson River watershed, NY, USA. Our goal was to better understand influences of historical habitat loss on anadromous fishes and determine to what extent and under what conditions novel habitat created by canal infrastructure might confer increased population abundance. We found that access to historical habitat in the upper Hudson River increased population abundance at all upstream dam passage rates with sufficient downstream survival of adult and juvenile Blueback Herring, but that abundance decreased with increasing upstream passage relative to the “no passage” scenario when downstream survival through dams was not sufficiently high. Access to novel spawning habitat in the Mohawk River canal system resulted in increased abundance of Blueback Herring when downstream survival of adults and juveniles was at least 0.80 per dam and both upstream passage and probability of using the Mohawk River were both greater than about 0.25. Both mortality during upstream passage of locks in the Mohawk River and marine fishery mortality had the potential to reduce Blueback Herring abundance below historical population abundance despite access to novel spawning habitat. These results highlight the complexity associated with effects of upstream and downstream fish passage standards on population responses while emphasizing similarities observed in other diadromous species and watersheds.

Fish Biodiversity and Suggested Conservation Measures of Transboundary River Someshwari in Netrokona, Bangladesh

Considering the importance of fish biodiversity for sustainable management of river fisheries, this study aims to explore and evaluate the fish biodiversity of Someshwari River along with conservation measures from November 2020 to October 2021. Data collection was carried out in Jaria, Susang Durgapur, Shivganj Bazar and Bijoypur of Netrokona district. Questionnaire interview, Focus Group Discussion (FGD), Direct observations, Key Informant Interview (KII) was used to collect data. During the study period, 23 species under 12 families were determined. Among them 6 finfish species are endangered, 4 are critically endangered, 5 are vulnerable, 7 are data deficient, and 2 are not threatened, respectively which includes highest catch catfishes at about 26.62%. However, the lowest amount catch constituted the Miror carp of about 5.29%. After the catfish, the second highest catch was 15.9% of small prawn. Another dominant group major carps contained 11.26%, and barbs remained at 11% of the catch and the loaches constituted 1.3% of the total catch. In addition, other groups like Mola carplet 7%, gourami 2.20%, Spiny eels 9.86% etc. were found in the Someshwari river. There were about 81% fish for food and 17% ornamental fish. Fourteen distinct types of fishing equipment were used namely: nets, traps, hooks, and lines, and wounding equipment. Finally, indiscriminate use of harmful gear, extraction of sand and rock, inadequate supervision of Governments and Non Governemental orgazizations, pollution from the adjacent areas, high interest rate of bank loan were understood as common constraints in the study area. Therefore, recommendations were made to improve river fisheries management through habitat restoration, increasing public awareness, prohibition on exploiting brood fish and active participation for sustainable catch.

Revealing the reproductive biology and growth dynamics of Arius maculatus (Thunberg, 1792) in the Mekong Delta estuary, Vietnam

Referring to the Mekong River, it is the largest river in Southeast Asia's Indo-Burma biodiversity hotspot, and it sustains a diverse range of fish species. In order to manage the river's fisheries in a sustainable way, it is important to have a comprehensive understanding of population dynamics. This study focuses on the spotted catfish, Arius maculatus (Thunberg, 1792), which is commercially valuable and found in the estuarine areas of the Mekong Delta, Vietnam. Monthly samplings were conducted at Tran De and Dinh An estuaries from July 2017 to May 2019, revealing distinct patterns in the gonad-somatic index (GSI) and hepato-somatic index (HSI). The spotted catfish were found to breed throughout the year, with peak breeding periods in March and August. The length at first maturity (Lm) was determined to be 12.80 cm for males and 11.79 cm for females. The fecundity, although relatively low, was measured at 16 ± 3 yolks per female and 144 ± 60 hyalines. The Von Bertalanffy growth parameters were calculated as L∞ (the asymptotic length) = 20.6 cm, K (growth coefficient) = 0.5 year−1, and t0 (theoretical age at zero length) = − 0.603 year−1. The length at first capture (Lc) was found to be 8.93 cm. Evaluation of the mortality rates revealed that the spotted catfish population is being overexploited, as indicated by an exploitation rate (E) of 0.695, which exceeds the optimum level of 0.50. It is crucial to implement effective management strategies to ensure the sustainable fisheries of Arius maculatus in the Mekong Delta estuary in Vietnam.

A sustainable blue economy: blockchain and internet of things integration in tourism villages

Coastal areas have a wealth of marine and river fisheries resources that have great potential to be developed. This potential is utilized by various parties to make utilization efforts including fishing activities; conservation; ports; and marine cultivation; and coastal and aquatic tourism. Problems that currently occur in coastal areas include: (a) illegal fishing, (b) damage to ecosystems in coastal and marine areas, (c) not optimal utilization, (d) unsustainable development, (e) leakage of development due to corruption and injustice. The research methodology used is descriptive and qualitative research with framework analysis, which means framework analysis techniques. This analysis technique is carried out by conceptualizing the system through a structure that describes the connection between one variable and another in a systematic and detailed manner. The findings of this study provide innovative solutions for the application of financial and marketing technology through blockchain and the Internet of Things (IoT) can increase the productivity of fishermen, internal control, financial transactions, and reliable marketing strategies in helping business entities run their business processes. The management of regional potential independently and integrated can be collaborated through community empowerment and the role of village government through village-owned enterprises (BUMD) based on Sharia cooperatives in villages in coastal areas of Indonesia. So that the productivity of fishermen and government agencies in tourist villages can increase.

PIT tagging systems are suitable for assessing cumulative impacts of Mekong River hydropower plants on (upstream) fish migrations in Lao PDR

The Mekong River has the largest inland fishery in the world but is threatened by planned mainstem hydropower developments that could impact fish migration patterns. Here we provide direct evidence of long-distance migrations along the Mekong mainstem by Hypsibarbus malcomi, one of the 10 most important species in the Mekong River fishery. The migration included a 354 km passage through one current and three proposed hydropower developments. We tagged and released 233 wild fish, including 77 H. malcomi with Passive Integrated Transponder (PIT tags) near the capital Vientiane in April of 2022. Five PIT tagged H. malcolmi were detected at the top of the Xayaburi hydropower plant fish ladder within 15 months of being released at Vientiane. Our findings empirically demonstrate that this species undertakes long distance migrations in the main stem of the Mekong and therefore that suitable fish passage facilities will need to be incorporated in mainstem hydropower developments to meet their migratory needs. The findings also demonstrate the value of including a fishery independent and efficient monitoring technology, such as PIT tagging, to assess the migration patterns of fish in the face of upcoming developments in the Lower Mekong Basin.

Lipid Metabolic Disorders Induced by Organophosphate Esters in Silver Carp from the Middle Reaches of the Yangtze River.

The Yangtze River fishery resources have declined strongly over the past few decades. One suspected reason for the decline in fishery productivity, including silver carp (Hypophthalmichthys molitrix), has been linked to organophosphate esters (OPEs) contaminant exposure. In this study, the adverse effect of OPEs on lipid metabolism in silver carp captured from the Yangtze River was examined, and our results indicated that muscle concentrations of the OPEs were positively associated with serum cholesterol and total lipid levels. In vivo laboratory results revealed that exposure to environmental concentrations of OPEs significantly increased the concentrations of triglyceride, cholesterol, and total lipid levels. Lipidome analysis further confirmed the lipid metabolism dysfunction induced by OPEs, and glycerophospholipids and sphingolipids were the most affected lipids. Hepatic transcriptomic analysis found that OPEs caused significant alterations in the transcription of genes involved in lipid metabolism. Pathways associated with lipid homeostasis, including the peroxisome proliferator-activated receptor (PPAR) signal pathway, cholesterol metabolism, fatty acid biosynthesis, and steroid biosynthesis, were significantly changed. Furthermore, the affinities of OPEs were different, but the 11 OPEs tested could bind with PPARγ, suggesting that OPEs could disrupt lipid metabolism by interacting with PPARγ. Overall, this study highlighted the harmful effects of OPEs on wild fish and provided mechanistic insights into OPE-induced metabolic disorders.

Binga's VaTonga communities involvement in Zambezi river fishery resource harvesting and management

Fishing dependent rural communities in developing countries are poor despite staying close to resources which can improve their lives. This motivated this study to assess the participation of Binga District communities in exploitation and management of fishery resources. A descriptive research design supported by both qualitative and quantitative research methods was employed. Questionnaires, interviews, focus group discussions and observations were used to collect data, and Microsoft excel 2016 was used for data analysis. Findings indicate that the VaTonga Communities of Binga (Basilwizi) District are not exercising their full fishing rights as expected because of a combination of lack of knowledge, failure of local authorities to represent local people in development policy designing, poverty and lack of transparency on expected management and exploitation rights of fishery resources. It was confirmed that all people wish to participate in fishing but strict access rights and poverty are major constraints. Main challenges faced by fishers include disruption of activities by crocodiles and hippos, poaching by foreign people and fish markets. Results showed that there is potential of livelihood improvement for people if their access rights are revised and if they are fully capacitated to exploit and protect their resources through community based natural resource management program. Unlike other studies in the same research domain, a framework for sustainable exploitation of fishery resources was developed as way forward. The framework recommends revision of access rights for local people and donor support to capacitate them with fishing resources amongst other aspects that need attention to improve socio-economic development and ecological integrity in the national thrust of leaving no one and no place behind towards achievement of global sustainable development goals. These findings will be an eye opener to policy makers with regards to the consequences of neglecting local people of ignoring them in decision making.

Length-Weight Relationships and Growth Patterns of Eight Indigenous Fish Species from Lancang River, Southwest China

The Lancang-Mekong River watershed has extremely high fish biodiversity. With the rapid population growth and economic development in the river basin, fish diversity and fishery resources of this river are experiencing serious threats. Basic biological information on most fish species in the Lancang River, required to improve conservation in this area, is limited. This study aimed to provide new estimates of length-weight relationships (LWRs) by using the linear regression of W = aLb for eight indigenous fish species from the Lancang River, Southwest China. From 2018 to 2021, 534 specimens belonging to 3 families and 8 genera were collected using various types of fishing techniques. Standard length (SL) and body weight (BW) of each specimen were measured to the nearest 0.1 cm and 0.1 g, respectively. This study presents the first public records of LWR parameters of Schizothorax lissolabiatus, Poropuntius huangchuchieni, Tor sinensis, Scaphiodonichthys acanthopterus, Mystacoleucus lepturus, Hemiculterella macrolepis, Glyptothorax lampris, and Schistura porthos. The range of b values for the LWRs was 2.5378–3.1732, and the r2 values for all LWRs estimates ranged from 0.9102 to 0.9952. Intraspecific difference of b values across population and/or season was observed in S. lissolabiatus, T. sinensis, P. huangchuchieni, S. acanthopterus, and M. lepturus. The range of mean condition factor (K) and mean relative weight (Wr) was 0.97–2.39 and 100.29–108.18, respectively. This study updated information for FishBase and provided new record of maximum standard length for five species, namely, S. lissolabiatus, P. huangchuchieni, T. sinensis, S. acanthopterus, and M. lepturus. The findings of this study are essential for the management and conservation of locally indigenous fish and fisheries.

Social and Ecological Impacts of Fire to Coastal Fisheries: A Study of the Kenai River Fishery (Alaska,USA)

AbstractIn a rapidly changing environment where fires are becoming more frequent and severe, scientists and managers need information and tools to enhance understanding of the numerous ways in which fire can affect fisheries. We used Ostrom's social–ecological systems framework to structure the development and refinement of fuzzy cognitive maps with stakeholders across the Kenai River fishery in Alaska, USA. The process yielded a model characterizing the structure and function of the Kenai River fishery. The model was then used to guide interviews with stakeholders focused on the effects of the 2019 Swan Lake Fire. We identified seven direct pathways through which fire can affect the social and ecological components of a coastal fishery. We also used the model to guide a targeted literature review to further explore how fire can affect the components of the Kenai River fishery. This synthesis of information allowed us to develop a more complete understanding of the impacts of fire on the fishery—an understanding informed by input from local stakeholders (via our interviews) and relevant scientific and management literature (via our literature review). Lastly, we used the model to assess the fishery's vulnerability to fire. We discuss how early run Chinook SalmonOncorhynchus tshawytschaconstitute a highly vulnerable component of the system and have the greatest potential to impact the fishery as a whole through a chain of negative social and ecological interactions. This final step illustrates how the model can be used to assess the vulnerability of system components to specific threats. The model of the Kenai River fishery provides an empirically grounded and easily understood visual representation of the complex dynamics affecting coastal fisheries. As such, it can be used to structure discussions among managers and stakeholders, organize our understanding of how fire affects fisheries, and assess vulnerabilities to endogenous and exogenous stressors.

Utilization Of Hydro Vortex Energy In Watershed Conservation Efforts And Increasing Community Nutrition Through The Fisheries Sector And Educational Tourism In Songgon

The residents of Songgon District, who are generally farmers, make rice fields and plantations dominant in the community's economy. Once a year durian trees can be harvested and once a rice harvest, this makes agriculture and plantations the backbone of the source of life for Songgon District, which results in the villagers' income being only annual. So that the economic sector that is able to generate income for villagers both on a monthly and daily basis, such as in the fisheries and tourism sectors, needs special attention for the development of the rural economy, given the huge potential possessed by Songgon District. Garbage is a major problem in this place, for example on the banks of the Binau river which is located in Songgon Village/District, opposite the Songgon District Office to be exact, which used to be full of piles of garbage. Residents around are reluctant to pass or do activities around the watershed (DAS). Therefore we are here with Pertamina Muda present in the development of the river fisheries sector such as controlled fish stocking (pioneered by Mr. Wibi Untoro) in the Binau river flow path and by utilizing Hydro Vortex Energy is a solution that can be implemented because it is proven to improve the community's economy and public awareness of the environment.

The social-ecological system of the Kenai River Fishery (Alaska, USA)

We present a collaboratively developed social-ecological model of the Kenai River Fishery. We developed the model through iterative interviews with stakeholders throughout the Kenai Peninsula using a novel participatory Fuzzy Cognitive Mapping process grounded in Ostrom's social-ecological systems framework. Individual social-ecological models, developed one-on-one with stakeholders, were combined into a single aggregated model representing the system's structure and function. We validated this aggregated model through subsequent interviews with stakeholders and focused literature reviews. The result is a model that can: 1) illustrate the breadth and interconnectedness of the Kenai River Fishery's social-ecological system; 2) be used to facilitate discussions around management of the fishery; and 3) be used to explore the components and interactions that move the system toward or away from sustainability. Using the model, we identify how the nature of salmon (migratory) and their habitat (large and unpredictable) leads to uncertainty about effective management strategies. This uncertainty, in addition to a large and diverse set of resource users, creates conflicting management goals that ultimately limit the governance system in making decisions that might increase the sustainability of the fishery.

Pathogenicity of Plesiomonas shigelloides and Citrobacter freundii isolated from the endangered Chinese sturgeon (Acipenser sinensis)

Chinese sturgeon (Acipenser sinensis) is an indigenous species of China and is listed as a critically endangered species. Recently, second filial generations of Chinese sturgeon in the Yangtze River Fisheries Research Institute suffered from a severe disease. In this study, two kinds of pathogenic bacteria were isolated from diseased sturgeon and identified as Plesiomonas shigelloides and Citrobacter freundii, based on 16S rDNA gene sequence alignment analysis. Antimicrobial susceptibility testing showed that P. shigelloides was resistant to ampicillin, penicillin, midecamycin, oxacillin, and clindamycin; and sensitive to tocefatriaxone, piperacillin, cefoperazone, cefazolin, and ciprofloxacin. C. freundii was resistant to ampicillin, penicillin, midecamycin, oxacillin, and clindamycin; and sensitive to chloramphenicol, cefuroxime, norfloxacin, ciprofloxacin, and ceftazidime. The median lethal dose (LD50) values of P. shigelloides and C. freundii were 4.50 × 103 colony forming units (CFU)/g and 3.20 × 103 CFU/g, respectively. Clinical symptoms of challenged sturgeons were the same as those of naturally infected sturgeons. Histopathological examination disclosed severe damage in the viscera of P. shigelloides and C. freundii-infected sturgeons. This is the first report suggesting that P. shigelloides infection is associated with mortality of Chinese sturgeon. The results of this study revealed the pathogenesis and severe pathogenicity of P. shigelloides and C. freundii in cultured Chinese sturgeon, and offer insights into the prevention and treatment of bacterial infection caused by P. shigelloides and C. freundii in cultured sturgeons.

Surfing the tide: Homeward migration of sea trout (Salmo trutta) in a Patagonian river

This study evaluates the influence of marine and freshwater conditions on the timing of river entry and upstream migration of sea trout (Salmo trutta) in the Grande River of Tierra del Fuego, Patagonia. We analysed the in-river catch-and-release records from a group of fishing lodges that dominate the Grande River fishery during January-April 2008 (n=5029 fish) as a function of environmental variables: tidal amplitude, stage in the lunar cycle, river discharge, and river water temperature along the homeward migration season. We discuss the value of the daily catch rate as an abundance index in the Grande river, then analyse the temporal structure of the tidal cycle in the Grande River estuary, a macro-tidal environment with a mean tidal amplitude of 5.7m, and analyse the fit of a generalized additive model to trout catches on a daily basis in four sections along the river to identify the environmental variables that may affect trout abundance throughout the homeward migration. Fish catches in each section of the river were differentially affected by specific environmental variables: tidal amplitude had a positive and significant effect on catches in the lower river sections, whereas water temperature and river discharge significantly affected catches in upper sections (positive effect of temperature; negative effect of discharge). Catches in the lower section clearly reflect the river entry stage of the homeward migration, with a bi-modal shape significantly correlated with the tidal cycle. The first peak was composed mainly of larger multi-sea-winter trout that move upstream, whereas the second one had a wider range of fish lengths, including a large proportion of small and maybe nonreproductive trout that overwinter in the lower river. Based on our results, we conclude that the large tides in the Grande River estuary strongly affect the river entry timing of sea trout. The underlying mechanisms of this effect may be a combination of increased olfactory recognition and increased tidal transport modulated by the seasonal tidal cycle, which operates on trout during coastal migration to produce the pulses observed in the Grande River sea trout run. In the middle and upper sections of the river, where the tidal effect at river entry was dissipated as upstream migration progressed, trout catches increased with water temperature and decreased with river discharge, which may operate through their influence on in-river migration rate and abundance, but also through changes in catchability.

DAM IMPACT ON WATER QUALITY AND MORPHOMETRIC CHARACTERISTIC OF SCHIZOTHORAX SPECIES IN BHAGIRATHI RIVER OF UTTARKASHI, UTTARAKHAND

A study was conducted on the morphometric characteristics of Schizothorax species of fish on samples collected from Bhagirathi river in Uttarkashi district of Uttarakhand state. Samples were taken from the study sites to measure some important parameters of water quality, which greatly influenced the morphological characteristics of the fish. Morphometric features such as total length, pectoral, pelvic, anal, dorsal, head, caudal length of eyes, caudal width and weight were recorded. Significant effects of dam on fish are observed on the morpho-metric of Schizothorax sp. There was no change in the characters but the wall of the dam put the selection pressure. The maximum length, weight of fish was observed in the study area during winter season and minimum during rainy season. The maximum length and weight were found before the dam. Changes in habitat, physico-chemical parameters, less aquatic macro-invertebrates lead to shorter lengths of fishes. Proper management techniques should be required for the production of fish. This paper will provide knowledge of the impact of dam on the morphometric character of fish along with parameters of water quality. It also gives in-depth knowledge of proper management of river fisheries.

Basin‐scale approach needed for Yangtze River fisheries restoration

AbstractThe Yangtze River contains the highest fish diversity and most important inland fishery resources in China, but its biota and ecosystem services face an uncertain future. The river and its basin have undergone vast changes from centuries of human impacts, and fish stocks are in a particularly dire situation. A complete 10‐year moratorium on commercial fishing within the entire Yangtze River was implemented starting in January 2021. By itself, the ban on fishing will unlikely guarantee full recovery. We conclude that multiple human impacts to the basin and its fish stocks require multidisciplinary strategies implemented at the whole basin scale for effective conservation.

Historical reconstruction of sturgeon (Acipenser spp.) spatiotemporal distribution and causes for their decline in North-Western Europe

This study aims to reconstruct the historical spatiotemporal distribution of the anadromous sturgeons, Acipenser sturio and A. oxyrinchus, in NW-Europe (especially in the Rhine, Meuse, Scheldt, and Ems rivers, and in the North Sea), in light of evaluating the possibilities for their reintroduction. It is based on fisheries data from the 14th–twentieth century, consisting of > 5000 records of sturgeon landings and sales (c. 40,000 specimens) from the Netherlands, Belgium, Germany, Luxemburg, France and Switzerland. Most data originate from fisheries in the Rhine-Meuse delta (c. 28,000 specimens, 98% of the Rhine catches). Further upstream, far fewer sturgeons (c. 600 specimens) were reported from the Rhine’s mainstem and its principal tributaries, Mosel, Neckar and Main. Smaller tributaries and the Ems, Meuse, and Scheldt rivers seldom yielded sturgeons. This spatial pattern can be related to the species’ preference for large-river habitat, combined with fisheries activities that were most intensive in the delta areas. Sturgeon catches began to dwindle in the late nineteenth century, at a time when river engineering first strongly affected the sturgeon’s reproductive habitats in the Lower Rhine and delta areas. Also from then onwards, North Sea fishery pressure increased, as trawlers switched from sail to steam-powered propulsion. These sea fisheries harvested all age-classes of sturgeons year-round, including populations from other European rivers. The outcomes strongly suggest that NW-European sturgeon populations were initially impacted by intensive river fisheries, but especially by destruction of reproductive habitat, due to river regulation, and an intensified North Sea fishery, ultimately resulting in total population collapse.

Establishment of the comprehensive river environment conservation system in collaboration with river stakeholders on the Tenryu River

The sedimentation, turbid water and water quality are typical environmental issues for dams and reservoirs which have impact on the reservoir and downstream of dams. These impacts are influenced from the upstream of a dam, and influence to the downstream. Therefore, a more integrated environmental management approach and consideration have been required for the whole river system. The Tenryu River in Japan flows through the erodible area near the Median Tectonic Line on Honshu, the main island of Japan, and continuously carries a lot of sediment during floods. The “Tenryu River Natural Resources Rebirth Promotion Committee” was established in 2012. The purpose of the committee is to restore fish resources and improve the river environment. The feature of the liaison committee is that it is composed of the Tenryu River fisheries association, academic experts, and dam owner and exchanges knowledge and technology information in spite of each interest. The current activities are related to the theme of “attached algae/environmental DNA survey”, “turbid water measures in reservoir/spawning bed construction technique at downstream,” and “information dissemination”. In this paper, the activities of the comprehensive reservoir and river environment conservation system in collaboration with river stakeholders are introduced and described, including future prospects.

Is traditional fisheries management correctly addressing the possible causes of fish production decline? The relationship between environmental degradation and artisanal river fisheries in the Magdalena River basin, Colombia

Context Overfishing has been historically considered as the main cause of fish stock depletion in the Magdalena River basin, Colombia, whereas the environmental context in which fisheries take place has not been considered. Aims The purpose of this research was to answer the following question: have anthropic activities, other than fishing, influenced the decrease in fishery production in the Magdalena River basin between 1980 and 2015? Methods We analysed diverse variables that were used as proxies for different environmental degradation processes, including sediment load, forest cover, flow rates, reservoir volume <1200 m above sea level, gold production and human population growth. We compared these variables with fishery production between 1980 and 2015 by using cluster analysis, principal-component analysis (PCA) and principal-component regression (PCR). Key results Our findings confirmed that environmental degradation accounts for 61% of the reduction of fishery production. Conclusions The traditional approach of holding fishers accountable for the decline of fishery production is misleading, and, therefore, a better understanding of the overall system is necessary before implementing restrictions on fishing activities. Implications Hence, fishery management should also integrate economic and social variables that affect ecosystem services within the basin into the analysis and decision processes.

FISH-DIVERSITY IN THE KURA RIVER OF BANGLADESH: PATTERNS AND THREATS

The study was aimed to investigate the current status and threats of fisheries resources in the Kura River, Bangladesh. Monthly fish catch surveys were carried out from December 2015 to November 2016 in four catchment areas at Hasinarghat, Kandir-dor, Pulertol, and Barartok. In addition, questionnaire interviews and focus group discussions (FGD) were done to clarify perceptions about the Kura River fishery status. A total of 59 fish species from 22 families were documented and of which 27% were threatened. The values of diversity (H), richness (D), and evenness (J’) were calculated at 3.599, 4.345, and 0.921 respectively. The highest catch volume was recorded 19800±7722.71 kg in November 2016 at the Kandirdor and the lowest 225±110.65 kg in March 2016 at the Barartok (p<0.05). The upstream blockage (man-made dam) in the Kura River was identified as the main cause of fish habitat change, decrease fish biodiversity, and production of this River. Therefore, the findings of this study exposed that the conservation of fish has become urgent. In this regard, the baseline scenario of the Kura River biodiversity and threats will help to make awareness to take necessary conservation strategy as well as the need for further in-depth study.