Traditional Habitat Research Articles

A comparison of recreational and survey-grade side-scan sonar systems in mapping reservoir fish habitat

Abstract Objective Littoral zone aquatic habitat is an important component of sport fish population dynamics in freshwater lakes and reservoirs and is a primary target of fisheries management actions. However, habitat data for these systems are often minimal or nonexistent due to the cost and time-consuming nature of traditional aquatic habitat sampling methods. Side-scan sonar has been identified as a potential tool that can address these limitations, allowing quantification of habitat features over large areas. Side-scan sonar is available in two forms: recreational (consumer grade) and professional (survey grade). Our goal was to compare these two grades of side-scan sonar by analyzing their ability to map littoral habitat features in three Ohio reservoirs. Methods We used a Lowrance Active Imaging 3-in-1 system (≈US$2000) recreational sonar and an EdgeTech 6205 system (≈$150,000) survey-grade sonar to collect imagery in the littoral zones of reservoirs. We manually quantified submerged woody debris, standing timber, aquatic vegetation, and benthic substrate in a geographical information system (GIS) using imagery from each sonar system and compared habitat estimates and GIS processing times. We analyzed how differences in image resolution between the two sonar systems affected the level of variation in habitat classification values generated by individual analysts. Result We found small differences in habitat classification values and accuracy between the two sonar systems, and trade-offs existed in spatial accuracy and ability to image dense vegetation. However, side-scan data acquisition, postprocessing, and habitat classification were generally less time-intensive with the recreational Lowrance system than with the survey-grade EdgeTech system. Unexpectedly, the lower quality Lowrance imagery had less user-based variation in GIS habitat classification. Conclusion Recreational side-scan sonar systems such as the Lowrance system provide sufficient imagery resolution, habitat classification values, and accuracy at a lower cost and with less processing time than survey-grade side-scan sonar systems and are useful tools for quantifying littoral habitat features in reservoirs.

The spatiotemporal changes of crab community in the Yangtze River Estuary after the fishing ban

The Yangtze River Estuary is the traditional habitat of fishery resources in China and also one of the crab fishing sites, but nowadays the crab resources have been seriously affected by high-intensity anthropogenic disturbance. To understand the composition and diversity of crab community following the fishing ban, six surveys were conducted from August 2022 to November 2023 using the single-bag trawl method. This study examined the crab community composition, biodiversity, resource density, spatiotemporal distribution patterns, and main influencing factors. Results indicated that a total of 14 crab species lived in the Yangtze River Estuary. Matuta planipes and Portunus trituberculatus were dominant crabs in summer 2022. P. trituberculatus, Eriochier leptognathus, and Charybdis japonica were dominant crabs in autumn 2022. Then, E. leptognathus and Eriocheir sinensis were dominant crabs in winter 2023. Notably, the largest numbers of dominant crabs appeared in spring 2023, including M. planipes, P. trituberculatus, E. leptognathus, C. japonica, and E. sinensis. Three same dominant crabs (M. planipes, P. trituberculatus, C. japonica) were identified in the summer and autumn of 2023. Thereinto, P. trituberculatus was the most dominant crab. The abundance and biomass trends of estuary crabs were winter< spring< autumn< summer. The community diversity index, evenness index, and richness index were winter< summer< autumn< spring, indicating the seasonal changes in abundance, biomass, and biodiversity. Correlation and redundancy analysis revealed that dissolved oxygen and salinity were the most critical environmental factors, which affect the changes in crab community in the estuary. This study revealed the changing characteristics of crab resources in the Yangtze River Estuary after the fishing ban, and provided the essential data and scientific basis for resource conservation and management decisions.

Urban Pest or Aussie Hero? Changing Media Representations of the Australian White Ibis.

The Australian White Ibis (Threskiornis molucca) is an Australian native bird species whose traditional habitat is inland wetlands. Environmental factors have seen the species steadily relocate to the eastern coast of Australia over the last few decades, primarily settling in cities. In 2016, McKiernan and Instone identified that 70% of Australian newspaper reports about the urban ibises from 1998 to 2012 presented the birds as either pests or victims. Since then, the ibis populations have grown, leading to the ibis being voted one of the top ten most commonly seen urban backyard birds in 2019. Media representation both reflects and shapes public perception and understanding, so it is timely for a contemporary investigation into how the ibis is represented in Australian newspapers. Has newspaper representation of the Australian White Ibis changed since 2013? If so, what new narratives have emerged? A content analysis of 68 Australian newspaper items from 2013 to 2024 was conducted with results showing a decrease in pest and victim narratives and the introduction of two new positive narratives-survivor and hero. This finding evidences changes in media representation pointing to potential changes in public understanding of the ibis and the possibility of improved relations between humans and the native bird species.

The role of wild bees and cavity-nesting wasps as ecological indicators of the last traditionally managed meadows in Eastern Europe.

The number of wild bees and cavity-nesting wasps is abundant in agricultural areas and they contribute significantly to ecosystem services. Due to their specialization in nesting sites and food sources, these groups are sensitive to habitat condition changes and they are therefore important indicators for environmental impact assessments. As semi-natural habitats are steadily declining and often understudied, their significance for research is increasingly recognized. During this research, the role of wild bee species and cavity-nesting Hymenopteran taxa as indicators was examined, along the unique combination of high nature value and traditional land use habitats in Eastern Europe, Transylvania. Transects and trap nests were used to test the diversity and abundance of wild bees and cavity-nesting Hymenopterans to identify possible differences between highly protected and less protected areas. The differences in taxonomic groups between the sites and the potential effects of landscape structure on wild bees and cavity-nesting Hymenopterans were also assessed. We detected a high diversity of wild bee species and a significant species replacement from one study year to another. Among the nest-building Hymenopteran taxa, the majority of nests was built by Trypoxylon sp. during both study years, with a stronger dominance in the second year. The different taxonomic groups of wild bees and cavity-nesting Hymenopterans showed differences in their habitat affinities. The majority of the sampled bumblebee species as well as Trypoxylon sp. had an affinity towards the study sites located within the highly protected study area. Altogether, we found different habitat preferences for different Hymenopteran groups (both wild bees and wasps) and conclude that these groups definitely have the potential to serve as indicators for differences in the intensity of land use.

Forecasting animal distribution through individual habitat selection: insights for population inference and transferable predictions

Habitat selection models frequently use data collected from a small geographic area over a short window of time to extrapolate patterns of relative abundance into unobserved areas or periods of time. However, such models often poorly predict the distribution of animal space‐use intensity beyond the place and time of data collection, presumably because space‐use behaviors vary between individuals and environmental contexts. Similarly, ecological inference based on habitat selection models could be muddied or biased due to unaccounted individual and context dependencies. Here, we present a modeling workflow designed to allow transparent variance‐decomposition of habitat‐selection patterns, and consequently improved inferential and predictive capacities. Using global positioning system (GPS) data collected from 238 individual pronghorn, Antilocapra americana, across three years in Utah, USA, we combine individual‐year‐season‐specific exponential habitat‐selection models with weighted mixed‐effects regressions to both draw inference about the drivers of habitat selection and predict space‐use in areas/times where/when pronghorn were not monitored. We found a tremendous amount of variation in both the magnitude and direction of habitat selection behavior across seasons, but also across individuals, geographic regions, and years. We were able to attribute portions of this variation to season, movement strategy, sex, and regional variability in resources, conditions, and risks. We were also able to partition residual variation into inter‐ and intra‐individual components. We then used the results to predict population‐level, spatially and temporally dynamic, habitat‐selection coefficients across Utah, resulting in a temporally dynamic map of pronghorn distribution at a 30 × 30 m resolution but an extent of 220 000 km2. We believe our transferable workflow can provide managers and researchers alike a way to turn limitations of traditional habitat selection models – variability in habitat selection – into a tool to understand and predict species‐habitat associations across space and time.

How does energy utilization affect rural sustainability development in traditional villages? Re-examination from the coupling coordination degree of atmosphere-ecology-socioeconomics system

In the face of global environmental challenges and China's commitment to achieving carbon neutrality, understanding the impact of energy transition in rural areas, particularly in traditional villages, becomes crucial for sustainable development. Based on 703 traditional villages in Hunan Province from 2005 to 2020, this study conducts a comprehensive spatiotemporal analysis of energy utilization, and analyzes the influence of energy utilization on the coupling coordination of the Atmosphere-Ecology-Socioeconomics System. The findings reveal a fluctuating trend in traditional villages' coupling coordination degree (CCD), particularly higher in western Hunan Province, and a notable reduction in regional disparities over time. The traditional villages' atmospheric conditions are better than the social and ecological conditions, which reflects the importance of improving socioeconomics and ecological subsystems for coupling coordination development. The study identifies that all seven energy utilization factors have positive effects on CCD. Forest vegetation carbon stocks and total energy consumption are critical drivers of CCD, highlighting spatial heterogeneity in their impacts on the CCD across different regions. Additionally, from 2005 to 2020, the effects of Forest Understory Vegetation Carbon Stocks on coupling coordination changed from widespread to localized, while Total Energy Consumption's impact was consistently localized. This paper reevaluates the role of energy management in enhancing the quality of traditional village habitats and offers valuable insights into environmental management and sustainable development in traditional villages, providing compelling evidence for policymakers.

Vertical habitat preferences shape the fish gut microbiota in a shallow lake.

Understanding the interactions between fish gut microbiota and the aquatic environment is a key issue for understanding aquatic microorganisms. Environmental microorganisms enter fish intestines through feeding, and the amount of invasion varies due to different feeding habits. Traditional fish feeding habitat preferences are determined by fish morphology or behavior. However, little is known about how the feeding behavior of fish relative to the vertical structure in a shallow lake influences gut microbiota. In our study, we used nitrogen isotopes to measure the trophic levels of fish. Then high-throughput sequencing was used to describe the composition of environmental microbiota and fish gut microbiota, and FEAST (fast expectation-maximization for microbial source tracking) method was used to trace the source of fish gut microbiota. We investigated the microbial diversity of fish guts and their habitats in Lake Sanjiao and verified that the sediments indeed played an important role in the assembly of fish gut microbiota. Then, the FEAST analysis indicated that microbiota in water and sediments acted as the primary sources in half of the fish gut microbiota respectively. Furthermore, we classified the vertical habitat preferences using microbial data and significant differences in both composition and function of fish gut microbiota were observed between groups with distinct habitat preferences. The performance of supervised and unsupervised machine learning in classifying fish gut microbiota by habitat preferences actually exceeded classification by fish species taxonomy and fish trophic level. Finally, we described the stability of fish co-occurrence networks with different habitat preferences. Interestingly, the co-occurrence network seemed more stable in pelagic fish than in benthic fish. Our results show that the preferences of fish in the vertical structure of habitat was the main factor affecting their gut microbiota. We advocated the use of microbial interactions between fish gut and their surrounding environment to reflect fish preferences in vertical habitat structure. This approach not only offers a novel perspective for understanding the interactions between fish gut microbiota and environmental factors, but also provides new methods and ideas for studying fish habitat selection in aquatic ecosystems.

О сакральных местах коренных малочисленных народов Севера в Арктической зоне Республики Саха (Якутия)

The traditional culture of the indigenous peoples of the North in the Republic of Sakha (Yakutia) is one of the priority values, but the active industrial develop-ment in their places of residence in the Arctic zone implies the vulnerability of their traditional way of life. This necessitates the formation of measures to pro-tect and preserve traditional culture, lifestyle and habitat. Sacred objects are also included in the system of specially protected natural territories along with the ter-ritories of traditional nature use of indigenous small-numbered peoples of the North. Taking into account the need to take urgent organizational measures to protect sacred sites and give them a legal status, work is underway in the republic to compile a Register of sacred sites of indigenous minorities of the North and their mapping. Taking into account the relevance of the work on compiling the Register, this article is devoted to the problem of sacred places of indigenous small-numbered peoples of the North living in extreme climatic conditions of the Arctic zone of Yakutia. In the Republic of Sakha (Yakutia), the total area of the Arctic zone is 1,701 thousand square kilometers, which is 55.2% of the territory of the republic and which includes 13 territories of municipalities of the Republic of Sakha (Yakutia).

Creating landscape‐appropriate habitat restoration strategies: success of a novel nesting habitat design for imperiled freshwater turtles

Turtle nesting habitat can be created as a restoration strategy to increase habitat availability or provide suitable habitat away from threats. Traditional nest habitat restoration consists of creating nesting mounds using a mix of sand and gravel. However, nesting mounds do not resemble natural turtle nesting habitat in a rock barren landscape where turtles nest in crevices and cracks in the bedrock. Therefore, our objective was to design and evaluate the success of a landscape‐appropriate design for turtle nesting habitat in a rock barren landscape. To evaluate success of the nest habitat design, we assessed the (1) survival of transplanted moss and lichen cover on created nest sites, (2) ecohydrological and physical conditions at created and natural sites, and (3) turtle egg hatching success at created and natural sites using a split‐clutch experiment. We found no difference in productivity between lichen transplants and natural sites, indicating that intact lichen transplants were successful. Moss transplant success was more variable due to moisture stress because transplants were conducted during dry conditions. In general, created nest habitat tended to have a more stable thermal and moisture regime compared to natural sites. When accounting for maternal effects, the odds of an egg hatching successfully was 6.6 times higher in a created site than a natural site. Overall, the success of our nest habitat design in the first few years suggests that this landscape‐appropriate design will be a useful restoration strategy for increasing turtle nesting habitat in rock barren landscapes.

Expanding the Associations between Landscape Characteristics and Aesthetic Sensory Perception for Traditional Village Public Space

Traditional village landscapes have a cultural and regional significance, and the visual aesthetic quality of the landscape is widely regarded as a valuable resource to benefit the health and well-being of urban residents. Although the literature has analyzed the influential mechanism of landscape features on aesthetic senses, most were from a single dimension. To improve the precision of the landscape aesthetic evaluation method, this study expanded the indicators for landscape characteristics of public spaces in traditional villages by incorporating multiple dimensions, such as landscape visual attraction elements and landscape color. It explored their associations with sensory preferences in a case study in Dongshan (a peninsula) and Xishan (an island) of Taihu Lake. We used multi-source data, a semantic segmentation model, and R language to identify landscape characteristic indicators quantitatively. The research results indicated that the accuracy of the aesthetic sensory assessment model integrating multi-dimensional landscape characteristic indicators was significantly improved; in the open space of traditional villages, the public preferred a scenario with a high proportion of trees, relatively open space, mild and uniform color tones, suitability for movement, and the ability to produce a restorative and peaceful atmosphere. This study can provide a guarantee for the efficient use of village landscape resources, the optimization of rural landscapes, and the precise enhancement of traditional village habitat.

КОМПЛЕКСНАЯ ПРОГРАММА ОРГАНИЗАЦИИ ПЕДАГОГИЧЕСКОГО СОПРОВОЖДЕНИЯ ПРОФЕССИОНАЛЬНОГО СТАНОВЛЕНИЯ МОЛОДЕЖИ ИЗ ЧИСЛА КОРЕННЫХ НАРОДОВ СЕВЕРА

The relevance of the article is due to the need of developing a Comperehensive Programme of Pedagogical Support for Professional Formation of the Youth from Among the Indigenous Peoples of the North considering the fact that community-minded, conscientious and competent professionals are needed.The purpose of the article is to provide rationale for the programme using the case of the Khanty-Mansiysk Autonomous Okrug – Ugra. The programme is focused on the formation of professional competency of college graduates representing the indigenous peoples of the North within the skills they acquire at the college, which are essential in their traditional habitats. The proposed article is the result of the researches carried out in 2019–2022, presented by the authors at research-to-practice conferences. The results of the researches also provided the basis for the dissertation.

Impacts Of Changes in Vegetation Structure on Elephant Habitat and Relationship to Human Conflict

With global climate change, ecosystems and biodiversity are facing unprecedented threats. Yunnan, as an important region for biodiversity, is experiencing significant vegetation structural changes, which have far-reaching impacts on its endemic elephant populations. This study focuses on how climate change-induced changes in vegetation structure affect Yunnan's elephant habitat and its conflict with humans. The study found that the elephants' traditional habitats have been severely fragmented due to climate change-induced forest degradation and grassland changes, forcing them to engage in more frequent conflicts with the local residents. This ecological change not only threatens the survival of elephants, but also puts enormous economic and livelihood pressures on the local communities. In addition, elephants' migration routes and behavioral patterns have been significantly altered as a result. This study reveals the complex impacts of climate change on biodiversity and human life, and emphasizes the urgency of taking appropriate measures to protect the ecological balance.

Assessment the Goat Value Chain in Mid Hills of Nepal

Goat value chain development and analysis is a recently introduced activity for enabling goat production activities to link to the market network. In Nepal, goat production is repeatedly reported rather traditional than commercial. The production volume of goat is the main drawback of goat value chain development in Nepal. Despite the visible market opportunities in the meat sub-sectors, the country has been unable to take advantage of the situation for various reasons. Some of the reasons include production constraints compounded by farmers' socioeconomic and institutional issues and their relationship with the market as a driving force. The study was conducted in six districts (Rolpa, Rukum, Salyan, Pyuthan, Gulmi and Argakhachi) using participatory value chain analysis tools as well as households survey. Total 120 goat producer households survey was done in six districts whereas 30 goat collectors, 30 wholesalers’/regional traders and 30 butchers/retailers surveyed were done. Total sample size of this value chain study of goat sub-sector was 300. It was understood that goat production system in the study area was traditional and the main drawback of value chain is the smaller production volume of goat. When market situation analyzed, it was learnt that there was no systematic marketing system attained by the farmers due to smaller production volume, though the goats contributed almost half of the livestock heads per household (6-8 heads/HH). Mainly the local breeds of goat (Khari) were reared by the farmers with some sorts of crossbreeding with improved breeds such as Jamunapari in Salyan and Rukum. Moreover, the prolificacy of goat was found poor than the average of the Khari goat, where twinning was only 50% as responded by the farmers. Likewise, the grazing system was also of traditional and goats were managed under sedentary system (semi-intensive by almost 60% farmers) and frequent feeding of concentrates in small amount was customary. The natural and traditional grazing habitats such as community forests and pasturelands were used extensively. Almost 40% of the respondents were positive to raise goats in a flock size of 15-25 in a given set of circumstances of support from the agencies, obviously larger flocks might require heavy investments for a level of family income. Later the cost of production and the existing marketing system of goat subsector was analyzed and found that the farmer’s profit is dominated by the profit of the t wholesalers and butchers, even though the profit share of farmers was almost one third of the production cost (250 NPR/kg live weight). Total market margin for live weight per kg goat was found about NRP 193 from study area to national market hubs. The market margin/profit gained by the farmers was almost 41%, 20% for local collectors, 60% for regional goat traders/wholesalers and 17% to the regional/national butchers/retailers. There is a need to follow a more integrated approach by investigating challenges and opportunities from production to consumption along a value chain, while also addressing policy and institutional aspects affecting goat production.

Backyard zoonoses: The roles of companion animals and peri-domestic wildlife.

The spillover of human infectious diseases from animal reservoirs is now well appreciated. However, societal and climate-related changes are affecting the dynamics of such interfaces. In addition to the disruption of traditional wildlife habitats, in part because of climate change and human demographics and behavior, there is an increasing zoonotic disease risk from companion animals. This includes such factors as the awareness of animals kept as domestic pets and increasing populations of free-ranging animals in peri-domestic environments. This review presents background and commentary focusing on companion and peri-domestic animals as disease risk for humans, taking into account the human-animal interface and population dynamics between the animals themselves.

Multimodel habitats constructed by perfusion and/or diffusion MRI predict isocitrate dehydrogenase mutation status and prognosis in high-grade gliomas

To determine whether tumour vascular and cellular heterogeneity of high-grade glioma (HGG) is predictive of isocitrate dehydrogenase (IDH) mutation status and overall survival (OS) by using tumour habitat-based analysis constructed by perfusion and/or diffusion magnetic resonance imaging (MRI). Seventy-eight HGG patients that met the 2021 World Health Organization WHO Classification of Tumors of the Central Nervous System, 5th edition (WHO CNS5), were enrolled to predict IDH mutation status, of which 32 grade 4 patients with unmethylated O6-methylguanine-DNA methyltransferase (MGMT) promoter were enrolled for prognostic analysis. The deep-learning-based model nnU-Net and K-means clustering algorithm were applied to construct the Traditional Habitat, Vascular Habitat (VH), Cellular Density Habitat (DH), and their Combined Habitat (CH). Quantitative parameters were extracted and compared between IDH-mutant and IDH-wild-type patients, respectively, and the prediction potential was evaluated by receiver operating characteristic (ROC) curve analysis. OS was analysed using Kaplan-Meier survival analysis and the log-rank test. Compared with IDH-mutants, median relative cerebral blood volume (rCBVmedian) values in the whole enhancing tumour (WET), VH1, VH3, CH1-4 habitats were significantly increased in IDH-wild-type HGGs (all p<0.05). Additionally, the accuracy of rCBVmedian values in CH1 outperformed other habitats in identifying IDH mutation status (p<0.001) at a cut-off value of 4.83 with AUC of 0.815. Kaplan-Meier survival analysis highlighted significant differences in OS between the populations dichotomised by the median of rCBVmedian in WET, VH1, CH1-3 habitats (all p<0.05). The habitat imaging technique may improve the accuracy of predicting IDH mutation status and prognosis, and even provide a new direction for subsequent personalised precision treatment.

Application of tonal audiometry methods to assess the hearing of grey seals in air and water environments

Anthropogenic noise load on the traditional habitats of marine mammals continues to increase due to the active development of the Arctic zone. The study of the hearing of Arctic seals is of great importance for the development of measures to reduce the impact of technogenic noise. During the study, a group of ten grey seals of different ages and genders has been trained to press a special key when demonstrating a pure tone sound with a frequency from the standard and extended set of frequencies recommended for pure tone audiometry. The experiments have been carried out by placing the key and the sound source in air and water (at a depth of 2 m) environment. The main indicator is the reaction time of the seal to the demonstrated stimulus. For each seal, individual audiograms for hearing in air and in water have been compiled using 32 frequencies. An analysis of the data obtained has shown that the reaction time can serve as an individual indicator in the study of the hearing of grey seals reflecting their age characteristics. According to the response time to sounds with different tone frequencies it is possible to establish biologically significant and indifferent frequencies for grey seals.

Environmental adaptation of traditional Chinese settlement patterns and its landscape gene mapping

Traditional Chinese villages are a successful example of active adaptation and effective use and protection of the environment. Traditional Chinese settlement landscapes form under the influence of geographical environments and environment-friendly ideas and have specific regional identities. Core factors of these residential areas can be considered cultural landscape genes. Based on this, this paper used gene analysis to identify traditional Chinese habitat patterns and decipher their environmental significance and cultural connotations. The results show that: Living patterns can be divided into six categories: ‘north-sitting or south-facing’, ‘Yin and Yang harmony’, ‘mountain-backed or water-facing’, ‘square-surrounded’, ‘psychological induction’, and ‘site-specific’ modes. These patterns correspond to the laws of orientation: Yin and Yang, mountain and water, security, auspiciousness, and synthesis, respectively. In their process of formation and development, traditional Chinese living patterns were deeply influenced by the traditional Chinese philosophical ideas of ‘Yin and Yang’, ‘the living earth’, ‘unity of heaven and human’, and ‘harmony between human and earth’. This study utilised the logical framework of gene identification, decoding, and expression to examine the characteristics and values of residential landscapes in traditional Chinese settlement patterns, and extracted the genome map of settlement pattern from a cross-regional perspective. This study has important implications for the construction of green habitats.

Traditional summer habitat use by Southern Resident killer whales in the Salish Sea is linked to Fraser River Chinook salmon returns

AbstractSouthern Resident killer whales (SRKW, Orcinus orca) are a small, endangered population of fish‐eating killer whales that inhabit coastal and inland waters of the western United States and British Columbia. SRKW have been in decline since 1995, with food availability, vessel disturbance, and pollutants proposed as drivers of their decline. We used 17 years of sightings data from the SRKW core summer habitat in the Salish Sea to examine trends in presence of SRKW, and how these trends may be related to the availability of a key food source, Fraser River‐origin Chinook salmon. We found that SRKW occupancy has declined by more than 75%, in step with reduced average catch per unit effort (CPUE) of Fraser River Chinook salmon. J pod was present in the core summer habitat most often, followed by K and L pods. All three pods demonstrated declines in visitation to the core summer habitat from 2004 to 2020, and presence of SRKW was significantly related to annual average Fraser Chinook CPUE. Our findings suggest that declining Fraser River Chinook returns may be reaching a point where SRKW cannot reliably meet their energetic needs, driving them to forage in areas outside of their traditional core summer habitat.

Effects of Constant Water Flow on Endurance Swimming and Fatigue Metabolism of Large Yellow Croaker

A trend in large yellow croaker (Larimichthys crocea) aquaculture is to establish production sites suitable for extreme weather conditions. However, continuous and strong currents can harm fish welfare. To determine a suitable site location, the swimming ability of large yellow croakers must be assessed. This study aims to provide novel insights into the physiological characteristics of large yellow croaker swimming and a reference for fishing and cage site selection. Currently, research on large yellow croakers has focused on behavior analysis. Herein, we investigate the effects of swimming on large yellow croakers’ metabolites by examining the preferred speed of the group and the sustained swimming ability of single-tailed fish. We evaluated factors that influence the large yellow croaker’s swimming fatigue by quantifying the metabolite contents and constructing a sustained swimming model. The results showed that large yellow croaker populations tend to grow in low-velocity environments, similar to their traditional habitat. The samples were taken at different swimming times at a flow velocity of 0.35 m/s. According to the results of the metabolite content analysis, blood glucose levels are closely associated with the swimming ability in large yellow croakers. The content of liver glycogen, which regulates blood glucose concentration, decreased in a certain linear relationship. The sustained swimming model of the large yellow croaker was constructed according to the changes in liver glycogen content. Based on our findings, we recommend the following: (1) for large yellow croakers with a size of approximately 13.5 cm (approximately 1 year old), the water velocity inside the cage should not exceed 2.6 BL/s; (2) the concentration of liver glycogen limits the sustained swimming ability of the large yellow croaker, providing a reference for studying the swimming ability of other fish.

Riverine health and the future of dolphins in northeastern India

Abstract The Gangetic Dolphin (Platanista gangetica) was once found in tens of thousands in the rivers of the Indian sub-continent, but the numbers have now dwindled abysmally throughout its geographical distribution. In northeastern India too, dolphins were seen in all the major rivers and also in certain wetlands during monsoon months till the early 1980s. However, the sighting of dolphins is rare now due to natural and human-induced factors. Three factors - adequate water cover, water quality, and abundance of prey food either individually or in combination- relate to River Dolphins’ existence. Variability of meteorological parameters also severely impacts on the limno-biological parameters of riverine habitats. Restoration of Gangetic Dolphins in their traditional habitats can boost ecotourism in the region. An extensive study is necessary to assess the cumulative impact of the proposed hydroelectric projects on the aquatic biodiversity of the entire eastern Himalayan region. The need of the hour is to adopt a holistic and participatory approach for maintaining riverine health and the prey base of the Barak and the Brahmaputra systems.