Invasive aquarium fish transform ecosystem nutrient dynamics

Freshwater fish are one of the most diverse groups of vertebrates, but are also amongst the most threatened. With contributions from leaders in the field, this is the first assessment of the global state of freshwater fish diversity, synthesising the opportunities, challenges and barriers facing the conservation of freshwater fish biodiversity. The book includes the first global assessment of the number, type and distribution of threatened freshwater fish species, discussing the features of freshwater fish biology and ecology that render so many species vulnerable to extinction. Introductory chapters on why freshwater fish are so sensitive to environmental change and disturbance lead into chapters providing detailed reviews of the key threatening processes and potential solutions. A concluding chapter summarises the key issues and looks to the future for opportunities and challenges for the conservation and management of freshwater fish.

This paper argues that if the goal of slowing global ecological degradation, and of sustained improvement in aquatic ecosystem health is to be achieved, then a departure is required from the traditional, discipline-focused approach to aquatic ecosystem health research and management. It argues that a shift needs to be made towards systemic, integrative, and holistic approaches, drawing on diverse disciplines, with values and ethics as fundamental to such approaches. The paper proposes the systemic-relational (SR) ethical framework to aquatic ecosystem health research and management as an essential contribution to addressing the potential intractability of the continuing deterioration of aquatic ecosystem health. The framework recognises the centrality of values in aquatic ecosystem health management, and the role of ethics in negotiating, and constructively balancing, conflicting values to realise healthy ecosystems in social–ecological systems (SES). The implications of the framework in terms of the research-practice interface, decision making, policy formulation, and communication are discussed.

The AEHMS, via its journal (Aquatic Ecosystem Health and Management) and the Ecovision World Monograph Series, has been actively engaged in promoting great/large lakes research. Consequently, it established a working group “The Great Lakes of the World-GLOW” for bringing together large lakes researchers to exchange ideas and technology. GLOW embarked on organizing special symposia which resulted in several peer-reviewed publications and special issues. In a short period of about 15 years, the AEHMS has published 11 peer-reviewed books under the banner of Ecovision World Monograph Series (Table 1).Over the past nine years 12 special issues of Aquatic Ecosystem Health and Management have been published dealing with great/large lakes (Table 2).Most of the manuscripts included in this special issue originated from the two sessions organized at the following international conferences: “Managing the large lakes of the world: Health, Integrity and risks”Limnological Congress (SIL), Montreal, Quebec, Canada, 2007“Great Lakes tomorrow: Research tools, toys and techniques”International Great Lakes Research Conference (IAGLR),Penn State University, University Park, Pennsylvania, 2007The papers have been categorized on a continental basis: North American, European and African, and reflect a great variety of topics across these continents. For North America, the themes comprised characteristics of poorly known Canadian lakes, geological history, remote sensing, and aquatic protected areas of the Great Lakes. The European contributions dealt with climate, water quality, phytoplankton, zooplankton, optical counters and remote sensing, the African papers focused mainly on fisheries of Lakes Victoria, Tanganyika, Kivu and Naivasha. One contribution, from Dr. Ken Minns, on Canadian lakes was an invited article.We hope that this issue provides a valuable exposé and comparison of the status and health of large ecosystems distributed across the three continents. Such comparisons are essential in providing insights into common themes (biodiversity, food web interactions, fish habitat, and fisheries), and threats (eutrophication, toxic chemicals, invasive species and climate change). They should also aid in the development of models and in application of emerging technology to improve our understanding, monitoring and management of these precious aquatic resources which face multiple stressors (Munawar, 1987; 2000; 2009).M. MunawarFisheries and Oceans CanadaChief Editor, Aquatic Ecosystem Health & Management

The Aquatic Ecosystem Health and Management Society (AEHMS) has been organizing activities in both freshwater and marine environments since its establishment. The Asia-Pacific region has received considerable attention from the Society as evidenced by several conferences organized in Malaysia, China, Vietnam and The Philippines. These conferences were followed by the publication of special issues of the journal Aquatic Ecosystem Health and Management (AEHM), each focusing on various topics which were presented (AEHMS, 2006a,b, 2009, 2012a,b).The decision to hold the ECOSEAS conference in Kuala Lumpur, Malaysia, originated from a meeting of a group of colleagues (F. Md. Yusoff, M. Munawar, G. Nagaraj, and N. A. M. Shazili) who envisaged convening conferences which focused on the ecosystem health of the Asia-Pacific seas, namely the South China Sea and surrounding seas including the Pacific Ocean. The first of this series was nicknamed ECOSEAS 1, held in Malaysia to spark interest in aquatic research in the Asia-Pacific region. We were indeed very pleased that the response of the scientists of the region was overwhelming, as evidenced by the scientific program which consisted of 8 keynote, 55 platform and 9 poster presentations. Altogether 29 papers were submitted to the journal, which were subjected to the standard peer review process. Nine articles have been accepted which are included in this issue. A few more are still undergoing peer review and revision.We hope this publication will enhance our knowledge of the Asia-Pacific aquatic ecosystem in combination with the five special issues the AEHMS has already published. I take this opportunity to thank the committee members given below who actively participated in the publication of this issue.This issue also includes four additional articles on Lake Superior based on papers presented at the “Ecology of Lake Superior” conference held in Duluth, Minnesota, organized by the USEPA and the AEHMS in 2010. These articles are part of a series of manuscripts focusing on the Ecology of Lake Superior published earlier in the journal (AEHMS, 2011). We are pleased that the series on Lake Superior is now complete.M. Munawar, Chief EditorAquatic Ecosystem Health and Management Society

In October 2002, the Fifth International Conference on Sediment Quality Assessment (SQA5) was held in Chicago, Illinois, USA, sponsored by the Aquatic Ecosystem Health and Management Society (AEHMS). Approximately 135 international scientists from 15 countries came together to discuss issues related to the sediment quality of various water bodies. The program consisted of 40 oral papers and 50 posters including Keynote lectures by D. Di Toro (U.S.A.), L. Thibodeaux (U.S.A.), P. Chapman (Canada), V. E. Forbes (Denmark), and A. P. Dufour (U.S.A.). The program was categorized in to the following themes: Sediment and watershed management;Sediment transport and contaminated flux;Weight of evidence and risk-based decision making;Microbial pathogens: Are sediments at risk; andEmerging technologies for assessment and remediation.This conference continued the successful tradition established through the preceeding four SQA conferences which were convened in Sweden (1994), Italy (1996), The Netherlands (1998) and Japan (2000). The next sediment quality meeting, SQA6, will be held in Antwerp, Belgium in August of this year. These conferences have followed the same objectives as AEHMS, addressing practical, ‘state-of-the-science’ aspects of sediment contaminant and stressor issues in aquatic ecosystems and the associated decision-making processes needed to protect and improve them. In the past 10 years, there have been dramatic improvements in the science of sediment assessment as well as many associated success stories featuring reduced impairment and ecosystem recovery. SQA5 in Chicago showcased continuing advances and understanding of complex interrelationships of the disciplines of ecology, chemistry, hydrology, toxicology, microbiology, weight-of-evidence decision making and modeling. The ten papers from this conference which appear in this issue of Aquatic Ecosystem Health and Management show the wide range of exciting issues that characterize this dynamic field, ranging from molecular and cellular level tools to modeling of multiple ecosystem processes to holistic based management approaches. Another set of papers originating from the SQA5 conference are scheduled for publication in another special issue of the journal. We hope that these papers will provide ‘state-of-the-art’ knowledge in sediment quality assessment and encourage researchers and managers to participate in future SQA conferences as this field matures.

The recruitment and biomass of a fish stock are influenced by their environmental conditions and anthropogenic pressures such as fishing. The variability in the environment often translates into fluctuations in recruitment, which then propagate throughout the stock biomass. In order to manage fish stocks sustainably, it is necessary to understand their dynamics. Here, we systematically explore the dynamics and sensitivity of fish stock recruitment and biomass to environmental noise. Using an age-structured and trait-based model, we explore random noise (white noise) and autocorrelated noise (red noise) in combination with low to high levels of harvesting. We determine the vital rates of stocks covering a wide range of possible body mass (size) growth rates and asymptotic size parameter combinations. Our study indicates that the variability of stock recruitment and biomass are probably correlated with the stock's asymptotic size and growth rate. We find that fast-growing and large-sized fish stocks are likely to be less vulnerable to disturbances than slow-growing and small-sized fish stocks. We show how the natural variability in fish stocks is amplified by fishing, not just for one stock but for a broad range of fish life histories.

Interactions among multiple anthropogenic stressors threaten freshwater fish and pose challenges for fisheries management and conservation. Previous studies of multiple‐stressor effects on freshwater fish suggest a prevalence of antagonistic interactions. However, taxonomy, life stage and/or environmental context likely modify the magnitude and direction of fish responses to multiple stressors. Stressor intensity, impact mechanism, exposure time and ecosystem size may further affect interaction outcomes. Large‐scale studies quantifying how these variables moderate stressor interactions are lacking. To address this knowledge gap, we performed a meta‐analysis of 29 factorial multiple‐stressor experiments to examine the influence of seven potential moderator variables on the magnitude and direction of stressor interactions. Using weighted random‐effects meta‐analytic models, we demonstrate the importance of taxonomic identity and life stage for interaction outcomes. In particular, Cypriniformes showed stronger antagonisms than Salmoniformes, as did larval fish compared to juveniles. Interaction outcomes also varied among the measured fish responses with survival yielding stronger antagonisms than biomass. Increasing experimental duration and volume of the experimental units both drove interactions towards synergisms, supporting findings from previous studies that synergisms take time and space to develop. In an era when the number of stressors affecting freshwater systems is increasing rapidly, our study provides a vital step towards identifying generalities in multiple‐stressor outcomes and thus improved predictions of multiple‐stressor impacts. Furthermore, our meta‐analysis complements studies in real streams, rivers and lakes by providing an experimentally derived context for the growing number of multiple‐stressor assessments in research, management and conservation of freshwater fish.

ABSTRACTAimFreshwater ecosystems cover less than 3% of the Earth's surface, yet support nearly 10% of all known animal species, majorly represented by freshwater fishes and amphibians, both of which are highly threatened groups. Geographically isolated freshwater species, such as those inhabiting islands, are at high risk. Australia, with nearly 9300 islands, is home to diverse island freshwater fauna. However, the lack of published literature on their island occurrence, threats and management impedes effective conservation across islands. We aim to describe the distributional patterns of amphibians and freshwater fishes on islands and analyse the island characteristics that influence these patterns.LocationAustralia's Islands.MethodsWe compiled the first database of occurrences of amphibians and freshwater fishes across Australia's islands. Utilising the database, we used regression analysis to examine the main drivers of distributional patterns, species richness and species composition on Australia's islands.ResultsWe found that 102 amphibians and 95 freshwater fishes occur on Australia's islands. Fifty‐five fishes were obligate freshwater species, 21 were euryhaline and 19 were diadromous. Although freshwater fishes showed lower richness on islands than amphibians, potentially due to lower survey efforts, fishes had a higher proportion of threatened and alien species. Islands with more precipitation that are closer to the mainland hosted higher amphibian richness, which likely retained mainland amphibian assemblages or were more easily colonised. In contrast, larger islands hosted higher freshwater fish richness, where diverse habitats were likely to sustain more species.Main ConclusionsUsing the new database compiled, we found that occurrences of amphibians and freshwater fishes on islands were influenced by climate, island size and distance from the mainland. This provides a baseline for follow‐up studies on phylogeny and biogeography. This research contributes to future conservation of amphibians and freshwater fishes on islands by revealing islands of potential conservation concern and lays the groundwork for future spatial prioritisation work.

Although species richness has been hypothesized to be highest at 'intermediate' levels of disturbance, empirical studies have demonstrated that the disturbance-diversity relationship can be either negative or positive depending on productivity On the other hand, hypothesized productivity diversity relationships can be positive, negative or unimodal, as confirmed by empirical studies. However, it has remained unclear under what conditions each pattern is realized, and there is little agreement about the mechanisms that generate these diverse patterns. In this study, I present a model that synthesizes these separately developed hypotheses and shows that the interactive effects of disturbance and productivity on the competitive outcome of multispecies dynamics can result in these diverse relationships of species richness to disturbance and productivity The predicted productivity diversity relationship is unimodal but the productivity level that maximizes species richness increases with increasing disturbance. Similarly, the predicted disturbance diversity relationship is unimodal but the peak moves to higher disturbance levels with increasing productivity Further, these patterns are well explained by the opposite effects of productivity and disturbance on competitive outcome that are suggested by the change in community composition along these two environmental gradients: higher productivity favours superior competitors while higher disturbance levels favour inferior competitors.

Ikan hias air tawar terdiri dari banyak jenis yang biasa dipelihara oleh para penghobi. Penghobi pemula seringkali melakukan kesalahan dalam memilih jenis-jenis ikan yang dapat dicampur dalam sebuah aquarium sehingga jenis-jenis ikan yang dipelihara dalam aquarium yang sama tidak kompatibel antara satu jenis dengan lainnya. Hal ini dapat menyebabkan kematian dini pada ikan yang dipelihara. Sehingga diusulkan sebuah pendekatan berbasis data mining dan machine learning dalam menentukan jenis-jenis ikan hias yang dapat dipelihara secara bersamaan dalam sebuah akuarium. Penelitian ini mengikuti kerangka kerja CRISP- DM yang bertujuan untuk mengembangkan sistem rekomendasi ikan hias air tawar guna membantu para penghobi akuarium, terutama para pemula dalam memilih spesies-spesies ikan yang sesuai untuk akuarium mereka. Sistem ini menggunakan teknik web scraping untuk mengumpulkan data dari fishkeepingworld.com, sebuah platform daring yang berisi artikel tentang ikan hias air tawar. Data yang terkumpul diproses, di- tokenisasi, dan diubah menjadi vektor kata menggunakan Word2Vec. Algoritma k-NN digunakan untuk menemukan spesies ikan serupa atau kompatibel. Akurasi sistem dievaluasi menggunakan Root Mean Square Error (RMSE) dengan menghitung rata-rata RMSE pada seluruh dataset. Pengujian dilakukan dengan memberikan beberapa nilai pada dimensi vektor untuk metode Word2Vec, jumlah K pada metode k-NN, dan metode perhitungan jarak pada k-NN. Sistem menghasilkan nilai RMSE terbaik dengan nilai 0.1329 pada K=3, jumlah vektor 400, dan perhitungan jarak dengan manhattan distance. Sistem rekomendasi yang dihasilkan diharapkan memberikan panduan yang bermanfaat bagi pengguna dalam meningkatkan pengalaman dalam hobi akuarium.Kata Kunci: CRISP-DM, ikan hias, sistem rekomendasi, k-NN.Freshwater ornamental fish consist of various species commonly kept by enthusiasts. Beginner hobbyists often make mistakes in selecting fish species that can coexist in the same aquarium, leading to compatibility issues and potential early mortality of the fish. Therefore, a data mining and machine learning-based approach is proposed to determine compatible ornamental fish species for simultaneous cohabitation in an aquarium. This research follows the CRISP-DM framework, which aims to develop a freshwater fish recommendation system to assist aquarium enthusiasts, especially beginners, in choosing suitable and compatible fish species for their aquariums. The system utilizes web scraping techniques to gather data from fishkeepingworld.com, an online platform featuring articles about exotic freshwater fish. The collected data is processed, tokenized, and transformed into word vectors using Word2Vec. A k-NN algorithm is employed to find similar or compatible fish species. The system's accuracy is evaluated using Root Mean Square Error (RMSE) by calculating the average RMSE across the entire dataset. Testing is conducted by providing various values for the Word2Vec vector dimensions, the number of neighbors (K) in the k-NN method, and the distance calculation method in k-NN. The system achieves the best RMSE value of 0.1329 at K=3, 400 vector dimensions, and using the Manhattan distance calculation method. The resulting recommendation system hopefully provides valuable guidance for users, enhancing their aquarium hobby experience.Keywords: CRISP-DM, ornamental fish, recommendation system, k-NN.

The The health of aquatic ecosystems is crucial for ecological balance and human well-being. This study explores recent advances in monitoring and managing aquatic ecosystem health, focusing on technological innovation and policy integration. It evaluates various advanced monitoring technologies, including remote sensing, IoT devices, biological monitoring methods, and big data analysis, applied to different water bodies such as lakes, rivers, and wetlands. These technologies provide comprehensive and detailed water quality data, enabling real-time monitoring and trend prediction. Additionally, the study analyzes the advantages and limitations of these technologies, such as high data acquisition costs, technical maintenance complexity, and data analysis bottlenecks. To address these challenges, it proposes enhancing monitoring and management efficiency through interdisciplinary collaboration and public participation. On the policy front, it discusses how sustainable water resource management can be achieved through legal frameworks, government-community cooperation, and international technological exchange. The study emphasizes the importance of integrating technology and policy and suggests future directions, including the development of cost-effective monitoring technologies, improvement of data analysis capabilities, and strengthening multi-stakeholder cooperation. This research provides a comprehensive reference framework for researchers and policymakers, aiming to promote the continuous development of aquatic ecosystem health monitoring and management.

The Gulf’s marine environment has long suffered due to anthropogenic stresses that negatively affect water quality, biodiversity, fisheries, and tourism, which are all economically critical to the ...

It was both an opportune time and a stroke of luck that I was offered the opportunity to work under the influence of two limnological titans, namely Drs. Richard Vollenweider and Jack Vallentyne at...

Biodiversity assessment is important for evaluating community conservation status. The haor basin in Sylhet Division represents a transitional zone with high species availability, rare occurrences and endemism. As a result, this study aims to describe the haor-based freshwater fish composition, including habitat, trophic ecology, availability and conservation status. Semi-structured questionnaires were used to collect data on fish samples through focus group discussions, field surveys, and interviews with fisheries stakeholders on a monthly basis. We identified 188 morpho-species, of which 176 were finfish and 12 shellfish, distributed into 15 orders and 42 families where 29%, 42%, 15%, and 14% species were commonly available, moderately available, abundantly available, and rarely available, respectively. Cypriniformes was the dominant order in both total species and small indigenous species identified. Approximately 45.34% of species were riverine, 31.58% floodplain residents, 12.55% estuarine, 2.83% migratory, and 7.69% were exclusively hill stream residents. Carnivores and omnivores were the most dominant trophic groups. A total of 87.76% species were used as food, 12.23% as ornamental and 6.91% as sport fish. Approximately 50 species were threatened (7 critically endangered, 23 endangered and 20 vulnerable) at the national level, most of them belonging to Cypriniformes and Siluriformes. Based on endemism, 16 species were endemic of which Sygnathidae, Cobitidae, Olyridae, Cyprinidae and Balitoridae fell under the threatened category. Minimizing intense fishing efforts, banning indiscriminate fishing and destructive fishing gear, initiating fish sanctuaries and beel nurseries, and implementing eco-friendly modern fishing technology are suggested to conserve the threatened species. This study represents a guideline for assessing the availability and conservation of freshwater fish in the Sylhet belt and serves as a reference for decision-makers in order to allow for the sustainable exploitation of fisheries resources within an ecosystem-based framework.

Assessing the aquatic ecosystem health status of lakes has been the focus of lake studies for domestic and overseas researchers and water resource managers. Poyang Lake, which is one of the only two remaining large Yangtze-connected lakes in the middle reaches of Yangtze River in China, provides considerable ecosystem service functions, such as flood water storage, water supply for industrial and agricultural production, maintenance of the unique and diverse biota of the entire Yangtze floodplain ecosystem, maintenance of regional ecological balance and so on. However, due to the impact of climate change and human activities, Poyang Lake has experienced drastic hydrological changes, water quality decline and aquatic ecological function degradation in recent years. An assessment of the aquatic ecosystem health of Poyang Lake is of great importance. On the basis of the index system construction principles and a meta-analysis of previous research, this paper puts forward the index system for the ecosystem health assessment of Poyang Lake. The indices contains the three element layers of aquatic organisms, hydrologic characteristics and trophic status and the five indicators of ratio of cyanobacteria biomass to diatom biomass (CB/DB), diversity index of macrozoobenthos, lowest water level anomaly during the dry season, mean water level anomaly during rising season and trophic state index (TLI). Then, the thresholds of indicators are determined using empirical study, frequency analysis, standard specification and so on. Aquatic ecosystem health status is categorised into three groups: 'good', 'moderate' and 'poor'. The study could provide theoretical basis for identifying the causes of the lake aquatic ecosystem health degeneration and protecting the environment of Poyang Lake. This present study provides an attempt to quantify the aquatic ecosystem health in a large floodplain lake with dramatic hydrological variations and will give some impetus for floodplain ecosystem assessment and management worldwide.