scholarly journals Fish Assemblage Structure and Environmental Correlates in Nepal’s West Rapti River, Banke

Our Nature ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 28-37
Author(s):  
Sujata Chaudhary ◽  
Jash Hang Limbu ◽  
Suren Subba ◽  
Jeevan Kumar Gurung ◽  
Naresh Pandey ◽  
...  
Keyword(s):  
Fish Assemblage ◽  
Fish Assemblages ◽  
Mesh Size ◽  
Temporal Variations ◽  
Assemblage Structure ◽  
Spatial And Temporal Variations ◽  
Fish Assemblage Structure ◽  
Environmental Correlates ◽  
Significant Difference ◽  
Fish Samples

The spatial and temporal variations of fish assemblages in rivers and streams of Nepal are poorly understood. So, the present study aimed to explore the spatial and temporal variations of fish assemblage structure in Nepal’s West Rapti River. The data were collected during autumn, winter and spring seasons, from October 2018 to April 2019. Fish samples were collected using cast net of 12 mm mesh size. A total of 28 species belonging to 7 orders, 10 families and 19 genera were recorded during the study. The analysis of similarity (ANOSIM) showed no significant difference among the stations and seasons. Based on cluster analysis, two major clusters were observed. The similarity percentage (SIMPER) analysis delineated that Cabdio morar (C14, 13.63%), Barilius bendelensis (C11, 10.32%), Gogangra viridescens (C22, 7.85%), Salmostoma phulo (C17, 7.74%), Labeo gonius (C5, 7.53%), Gagata cenia (C23, 6.45%), Garra gotyla (C6, 5.87%) and Labeo dyocelius (C2, 5.62%) were the most contributing species. The Canonical Correspondence Analysis (CCA) distinctly showed that the environmental variables dissolved oxygen, pH, carbon-dioxide, and water temperature play an essential role in shaping the fish assemblage structure of West Rapti River.

scholarly journals Correlations Between Fish Assemblage Structure and Environmental Variables of Taruwa Pond in Nawalparasi District, Province No. 4, Nepal

2021 ◽  
Vol 11 (1) ◽  
pp. 1-8
Author(s):  
JASH HANG LIMBU ◽  
KESHI CHAUDHARY
Keyword(s):  
Temporal Variation ◽  
Fish Assemblage ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Mesh Size ◽  
Assemblage Structure ◽  
Fish Assemblage Structure ◽  
Fish Community Structure ◽  
Water Parameters ◽  
Analysis Of Similarity

The correlations between fisheries diversity and environmental variables of Nepal’s Pond are poorly understood. This study aims to investigate temporal variation of fish assemblage at Taruwa Pond in Nawalparasi district, Province no. 4, Nepal from October 2018 to April 2019. For the fish agglomeration, cast net of 4 kg in weight and 3.80 m in length and 22.5 m breadth with 12 mm mesh size was used. In total, 579 individuals representing 16 fish species, 10 families, and 12 genera were recorded. According to similarity percentage analysis, the most contributory species were Puntius ticto (27.92%) followed by Danio devario (12.06%), Puntius terio (9.76%), Badis badis (7.31%), Lepidocephalichthys guntea (5.57%) and Puntius sophore (5.57%). Analysis of similarity suggested that fish community structure was significantly different in temporal variation (R = 0.321, p<0.01). Based on the cluster analysis, fish assemblages were isolated into two distinct groups at Bray-curtis similarity. The Canonical Correspondence Analysis distinctly indicated that the water parameters of dissolved oxygen, carbon-dioxide, depth, and water temperature play an important role in influencing the fish assemblage structure of Taruwa Pond.

scholarly journals Regional, watershed, and site-specific environmental influences on fish assemblage structure and function in western Lake Superior tributaries

2005 ◽  
Vol 62 (6) ◽  
pp. 1254-1270 ◽  
Author(s):  
John C Brazner ◽  
Danny K Tanner ◽  
Naomi E Detenbeck ◽  
Sharon L Batterman ◽  
Stacey L Stark ◽  
...  
Keyword(s):  
Fish Assemblage ◽  
Brook Trout ◽  
Fish Assemblages ◽  
Lake Superior ◽  
Structure And Function ◽  
Assemblage Structure ◽  
Fish Assemblage Structure ◽  
Site Specific ◽  
Western Lake ◽  
And Function

The relative importance of regional, watershed, and in-stream environmental factors on fish assemblage structure and function was investigated in western Lake Superior tributaries. We selected 48 second- and third-order watersheds from two hydrogeomorphic regions to examine fish assemblage response to differences in forest fragmentation, watershed storage, and a number of other watershed, riparian, and in-stream habitat conditions. Although a variety of regional, fragmentation, and storage-related factors had significant influences on the fish assemblages, water temperature appeared to be the single most important environmental factor. We found lower water temperatures and trout–sculpin assemblages at lower fragmentation sites and higher temperatures and minnow–sucker–darter assemblages as storage increased. Factors related to riparian shading and flow separated brook trout streams from brown trout (Salmo trutta) – rainbow trout (Oncorhynchus mykiss) streams. Functionally, fish assemblages at lower fragmentation sites were dominated by cold-water fishes that had low silt tolerance and preferred moderate current speeds, while fishes with higher silt tolerances, warmer temperature preferences, and weaker sustained swimming capabilities were most common at higher storage sites. Our results suggest that site-specific environmental conditions are highly dependent on regional- and watershed-scale characters and that a combination of these factors operates in concert to influence the structure and function of stream fish assemblages.

scholarly journals Fish Assemblage Structure Comparison between Freshwater and Estuarine Habitats in the Lower Nakdong River, South Korea

2020 ◽  
Vol 8 (7) ◽  
pp. 496
Author(s):  
Joo Myun Park ◽  
Ralf Riedel ◽  
Hyun Hee Ju ◽  
Hee Chan Choi
Keyword(s):  
Fish Assemblage ◽  
Fish Assemblages ◽  
Estuarine Fish ◽  
Freshwater Species ◽  
Fish Assemblage Structure ◽  
Nakdong River ◽  
Structure Comparison ◽  
Significant Difference ◽  
Freshwater Habitats ◽  
The Nakdong River

Variabilities of biological communities in lower reaches of urban river systems are highly influenced by artificial constructions, alterations of flow regimes and episodic weather events. Impacts of estuary weirs on fish assemblages are particularly distinct because the weirs are disturbed in linking between freshwater and estuarine fish communities, and migration successes for regional fish fauna. This study conducted fish sampling at the lower reaches of the Nakdong River to assess spatio-temporal variations in fish assemblages, and effects of estuary weir on structuring fish assemblage between freshwater and estuary habitats. In total, 20,386 specimens comprising 78 species and 41 families were collected. The numerical dominant fish species were Tachysurus nitidus (48.8% in total abundance), Hemibarbus labeo (10.7%) and Chanodichthys erythropterus (3.6%) in the freshwater region, and Engraulis japonicus (10.0%), Nuchequula nuchalis (7.7%) and Clupea pallasii (5.2%) in the estuarine site. The fish sampled were primarily small species or the juveniles of larger species at the estuary region, while all life stages of fishes were observed at the freshwater habitats. The diversity patterns of fish assemblages varied greatly according to study site and season, with higher trends at estuarine sites during the warm-rainy season. No significant difference in diversity between freshwater and estuarine sites during the cold-dry season were found. Multivariate analyses of fish assemblage showed spatial and seasonal differences of assemblage structures. Higher effects of between-site variability but not within seasonal variability at each site were observed. Variations in assemblage structures were due to different contributions of dominant species in each habitat. Common freshwater species characterized the fish assemblage in the freshwater region, while marine juveniles were significantly associated with the estuarine habitat. The results from the ecological guild analyses showed distinct ecological roles for freshwater and marine species, and overlapping roles for fish sampled at the fishways. The lower reaches of the Nakdong River are an important ecosystem for both freshwater and marine juveniles. Nakdong River estuarine residents and migrant fishes, however, have been negatively affected by the construction of the weir (gravity dam), due to the obstruction to migration from and to freshwater habitats. Conservation and management policies aimed at minimizing anthropogenic influences on estuary ecosystems should focus on evaluating ecological functions of estuary weirs.

Temporal variability in fish assemblage structure and recruitment in a freshwater-deprived estuary: The Coorong, Australia

2010 ◽  
Vol 61 (11) ◽  
pp. 1298 ◽  
Author(s):  
Brenton P. Zampatti ◽  
Christopher M. Bice ◽  
Paul R. Jennings
Keyword(s):  
Fish Assemblage ◽  
Fish Assemblages ◽  
Marine Species ◽  
River Regulation ◽  
Assemblage Structure ◽  
Estuarine Fish ◽  
Fish Assemblage Structure ◽  
Murray River ◽  
Eastern Australia ◽  
Freshwater Inflows

River regulation can diminish freshwater flows to estuaries and compromise estuarine functionality. Understanding biotic responses to altered flow regimes is imperative to effectively manage aquatic ecosystems. The present study investigated temporal variation in fish assemblage structure and the recruitment of catadromous fish in the Coorong estuary at the terminus of the Murray River, in south-eastern Australia. Over the three-year study period, freshwater inflows to the estuary diminished and ultimately ceased, disconnecting freshwater and estuarine environments. It was hypothesised that these conditions would lead to (1) increases in estuarine salinities and concomitant changes in fish assemblage structure and abundance, and (2) decreased recruitment of catadromous fish. As freshwater inflow decreased, salinities immediately downstream of a series of tidal barrages increased from brackish to marine–hypersaline, species richness and diversity decreased, freshwater and diadromous species became less abundant and assemblages were increasingly characterised by marine species. Furthermore, the abundance of young-of-year catadromous fish decreased dramatically. Excessive regulation of freshwater inflows is resulting in the Coorong estuary resembling a marine embayment, leading to a loss in species diversity. We suggest, however, that even small volumes of freshwater may promote diversity in estuarine fish assemblages and some recruitment of catadromous species.

scholarly journals The influence of depth on the Mediterranean reef fish assemblage revealed by the new video on underwater scooter method

2020 ◽  
Vol 61 (2) ◽  
pp. 145-162
Author(s):  
Igor Glavičić ◽  
Marcelo Kovačić ◽  
Dejan Paliska ◽  
Dani Laslo
Keyword(s):  
Reef Fish ◽  
Fish Assemblage ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Average Density ◽  
Depth Range ◽  
Fish Assemblage Structure ◽  
Visual Census ◽  
Reef Fish Assemblage ◽  
Significant Difference

The new video on underwater scooter method in combination with rebreather diving techniques was introduced and applied for visual census of fish assemblages. The presently applied method facilitates deeper visual census studies below 40 m, where they have rarely been done before due to the increasing research challenges with depth. The video on underwater scooter method is also expected to be less disturbing and faster compared to swimming divers. The method was applied in visual census study of fish assemblages from 8 to 50 m depth conducted at two locations in the east Adriatic using 102 video transects. The environmental variables contributing to the variation of the reef fish community in the depth range of the infralittoral and upper circalittoral bottoms were also recorded. Thirty-one fish species were recorded on transects and 10.3% of all individuals were not identified to the species level. The average density on transects was 0.8 individuals/m², with C. chromis, C. julis and G. auratus being both the most abundant and the most frequent species. Three environmental variables, depth, bottom with zoocover and eastern orientation of the coast, were identified as highly significant for species occurrence. Abundance and species richness of fish assemblages showed no significant variation with depths, inclinations, orientations and sites. A significant difference in the fish assemblage structure was found among orientations, depths and inclinations with the gradient change of species composition with increasing depth and with increasing inclination.

scholarly journals Fish Assemblage Structure in Al-Huwaizah marsh southern of Iraq after inscribed on the World Heritage List

2019 ◽  
pp. 1430-1441
Author(s):  
Basim M. Hubain Al-Thahaibawi ◽  
Kadhim H. Younis ◽  
Ithar K.A. Al-Mayaly
Keyword(s):  
Fish Assemblage ◽  
Native Species ◽  
Similarity Index ◽  
Chemical Properties ◽  
Assemblage Structure ◽  
Total Weight ◽  
Fish Assemblage Structure ◽  
Dominance Index ◽  
Fish Samples ◽  
Index Value

The fish assemblage structure in Al-Huwaizah marsh, southern of Iraq was assessed. Fish samples collected monthly by different fishing means from period December 2017 to November 2018. A total of 28959 individual of fish belonging to 9 families and 19 species were collected, 11 of them of native species and 8 of alienspecies. The numerical dominance index value (D3) of the highest three abundant species comprised 74.26% of the total fish caught, included Planiliza abu (Al-Keshny) 38.2% ; Coptodon zilli (Tilapia red abdomen) 29.41% and Carassius auratus (Prussian carp) 6.65%. The total weight of fish caught 2,190,680 tan, highest weight 312,242kg achieved in July, while lowest weight 41,590 kg found in September. The weight dominance index value (D3) of the highest three species in weight recorded 1,409,973 tan of the total weight of fish caught included C. zilli(Tilapia red abdomen) 659,994 kg , S. triostegus (Jerry fresh water) 495,784 kg and O. aureus (Blue tilapia) 245,195kg.The annual rate value for diversity, richness and evenness indices amounted 1.88, 1.75 and 0.64, respectively. Some of physical and chemical properties were studied such as water temperature which ranged from 11.5°C in January to 31.02°C in August month, dissolved oxygen ranged from 2.24 mg/l in September to 9.9mg/l in February, salinity varied from 1.37‰ in November to 3.76‰ in September and pH which ranged from 7.4 in June to 8.15 in December.Jaccard Similarity Index (Ss%) was used to know the similarity degree between the monthly catch samples. Also associations between distribution of fish species and the environmental variables were quantified by using canonical correspondence analysis (CCA). 

scholarly journals Fish Assemblage Structure in the Northwestern Hawaiian Islands Is Associated with the Architectural Complexity of Coral-Reef Habitats

Diversity ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 430
Author(s):  
Atsuko Fukunaga ◽  
Randall K. Kosaki ◽  
Kailey H. Pascoe ◽  
John H. R. Burns
Keyword(s):  
Coral Reef ◽  
Fish Assemblage ◽  
Fish Assemblages ◽  
Hawaiian Islands ◽  
Three Dimensional ◽  
Assemblage Structure ◽  
Fish Assemblage Structure ◽  
Northwestern Hawaiian Islands ◽  
Total Fish ◽  
Curtis Dissimilarity

The architectural complexity of coral-reef habitat plays an important role in determining the assemblage structure of reef fish. We investigated associations between the reef habitats and fish assemblages in the Northwestern Hawaiian Islands (NWHI) using in situ fish counts and data on habitat metrics and benthic community composition that were obtained from three-dimensional (3D) photogrammetric reconstructions of the surveyed sites. The structure of fish assemblage as a whole on the basis of Bray–Curtis dissimilarity, species richness and the abundances of herbivores and piscivores were associated with habitat metrics, with higher levels of architectural complexity generally supporting greater numbers of fish species and individuals. Benthic cover did not explain additional variation in these variables after the effects of habitat metrics were taken into account. Corallivorous fish was the only group that showed positive associations with both habitat metrics and benthic cover (Acropora and Pocillopora corals). The total fish abundance and the abundances of planktivores and invertivores did not show associations with either habitat metrics or benthic cover. This study suggests that an appropriate combination of habitat metrics can be used to account sufficiently for the effects of habitat architecture on fish assemblages in reef monitoring efforts in the NWHI.

Fish assemblage structure and relations with environmental conditions in a Rocky Mountain watershed

2004 ◽  
Vol 82 (10) ◽  
pp. 1554-1565 ◽  
Author(s):  
Michael C Quist ◽  
Wayne A Hubert ◽  
Daniel J Isaak
Keyword(s):  
Fish Assemblage ◽  
Brook Trout ◽  
Fish Assemblages ◽  
Cutthroat Trout ◽  
Rocky Mountain ◽  
Assemblage Structure ◽  
Fish Assemblage Structure ◽  
Mountain Watershed ◽  
Stream Geomorphology ◽  
Local Habitat

Fish and habitat were sampled from 110 reaches in the Salt River basin (Idaho and Wyoming) during 1996 and 1997 to assess patterns in fish assemblage structure across a Rocky Mountain watershed. We identified four distinct fish assemblages using cluster analysis: (1) allopatric cutthroat trout (Oncorhynchus clarki (Richardson, 1836)); (2) cutthroat trout – brook trout (Salvelinus fontinalis (Mitchell, 1814)) – Paiute sculpin (Cottus beldingi Eigenmann and Eigenmann, 1891); (3) cutthroat trout – brown trout (Salmo trutta L., 1758) – mottled sculpin (Cottus bairdi Girard, 1850); and (4) Cyprinidae–Catostomidae. The distribution of fish assemblages was explained by thermal characteristics, stream geomorphology, and local habitat features. Reaches with allopatric cutthroat trout and the cutthroat trout – brook trout – Paiute sculpin assemblage were located in high-elevation, high-gradient streams. The other two fish assemblages were generally located in low-elevation streams. Associations between habitat gradients, locations of reaches in the watershed, and occurrence of species were further examined using canonical correspondence analysis. The results suggest that stream geomorphology, thermal conditions, and local habitat characteristics influence fish assemblage structure across a Rocky Mountain watershed, and they provide information on the ecology of individual species that can guide conservation activities.

Aquatic connectivity and fish metacommunities in wetlands of the lower Great Lakes

2009 ◽  
Vol 66 (6) ◽  
pp. 933-948 ◽  
Author(s):  
Lynn D. Bouvier ◽  
Karl Cottenie ◽  
Susan E. Doka
Keyword(s):  
Species Richness ◽  
Great Lakes ◽  
Time Scales ◽  
Fish Assemblage ◽  
Fish Assemblages ◽  
Assemblage Structure ◽  
Analysis Of Covariance ◽  
Fish Assemblage Structure ◽  
Short Term ◽  
Aquatic Connectivity

Although many local and regional variables structure fish assemblage composition, few studies have assessed the effects of aquatic connectivity on fish assemblages in wetlands. Fish and habitat surveys were conducted in 12 wetlands across the lower Great Lakes basin in the spring and fall of 2003 and 2004. Spatial and temporal connectivity were classified into four connectivity classes to evaluate the interaction between aquatic connectivity and fish assemblage structure. Sequential, nested analysis of covariance was used to model the effect of habitat area and connectivity at long- and short-term time scales on aggregate descriptors of assemblage structure (i.e., species richness, piscivore richness, abundance, and diversity). Although no species–area relationship was detected, increases in connectivity were shown to positively affect species richness and piscivore richness. A variation decomposition method indicated that a combination of aquatic connectivity, followed by environmental and area variables, was most influential in structuring fish assemblages at short-term time scales. Connectivity thus influences both the local species pool present, as well as the abundance of these species within a wetland. Future fundamental and applied studies (e.g., climate change predictions, impact of humans on water budget, wetland management) on wetland fish assemblages should include connectivity as an important structuring process.

scholarly journals Assemblage structure and spatial diversity patterns of kelp forest-associated fishes in Southern Patagonia

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257662
Author(s):  
Mathias Hüne ◽  
Alan M. Friedlander ◽  
Enric Ballesteros ◽  
Jennifer E. Caselle ◽  
Enric Sala
Keyword(s):  
Fish Assemblage ◽  
Fish Assemblages ◽  
Anthropogenic Impacts ◽  
Fish Fauna ◽  
Spatial Diversity ◽  
Assemblage Structure ◽  
Kelp Forests ◽  
Fish Assemblage Structure ◽  
Important Species ◽  
Southern Patagonia

Knowledge of the ecology of the fish fauna associated with kelp (primarily Macrocystis pyrifera) forests in Southern Patagonia is scarce, especially in how abiotic and biotic variables influence their structure, diversity, and distribution. This information is important for the management and conservation of this unique ecosystem, which has minimal anthropogenic impacts at present. We analyzed data from 122 quantitative underwater transects conducted within kelp forests at 61 stations from Chile’s southern Patagonian fjords to the Cape Horn and Diego Ramirez archipelagos and the southern tip of Argentina, including the Mitre Peninsula and Isla de los Estados. In total, 25 fish species belonging to 13 families were observed. Multivariate analysis indicated that there are significant differences in fish assemblage structure among locations and wave exposures, which was driven primarily by Patagonotothen sima and Paranotothenia magellanica, which occurred on exposed and semi-exposed stations. P. cornucola was mainly distributed across sheltered stations of the Kawésqar National Park. Temperature, salinity, depth, and kelp density influenced fish assemblage structure, with the highest diversity in areas with the lowest temperature and greater depth at Isla de los Estados. In contrast, species richness, diversity, abundance, and biomass were all lower in areas with high density of the understory kelp Lessonia spp., which might be driven by the absence of P. tessellata, P. squamiceps and P. cornucola, the most important species in terms of occurrence, abundance, and biomass. Our study provides the first broad-scale description of the fish assemblages associated with kelp forests along the southern cone of South America based on non-invasive visual transects, improving our knowledge of the distribution of fish assemblages across several environmental conditions in this vast and little-studied area.

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