scholarly journals Composición y estructura de peces de la microcuenca del río Anchique, Tolima, Colombia

2017 ◽  
Vol 66 (1) ◽  
pp. 336
Author(s):  
Diana Carolina Montoya Ospina ◽  
Francisco Antonio Villa-Navarro ◽  
Edwin Orlando López-Delgado
Keyword(s):  
Environmental Variables ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
High Water ◽  
Structural Features ◽  
Fish Diversity ◽  
Substrate Composition ◽  
Significant Difference ◽  
Fish Samples ◽  
Magdalena River

The distribution and abundance of fish is influenced by multiple factors at temporal and spatial scales, and their community composition represent good river integrity indicators. The main objective of this study was to describe the composition and structure of fish assemblages along the Anchique river sub-basin (that drains to Magdalena river), and to test the hypothesis that these communities vary temporally and spatially. For this, four sites (E1, E2, E3 and E4) were sampled along the river (from river birthplace to Magdalena river), during the periods of high and low waters, in 2014. In each site, longitudinal transects (100 m long x 2 m wide, 60 min) were established and fishing was made with both electrofishing and trawl (10 m x 1 m, 0.05 m) nets. Fish samples were fixed and transported to the laboratory for posterior taxonomic identification with the use of keys; fish diversity and structure composition were calculated with the use of standard models. Besides, substrate composition and environmental variables were also considered. A total of 652 fish belonging to 36 species were recorded; high water showed higher values (325 fish with 32 species) than low water period (300 fish with 31 species). Siluriformes was dominant (51 %), followed by Characiformes (32 %), Gymnotiformes (5 %), Cyprinidontiformes and Cichliformes (6 %). Most abundant families were Characidae (28.3 %; 9 spp.), Loricariidae (23.4 %; 8 spp.) and Trichomycteridae (15.0 %; 2 spp.). Kruskal-Wallis test indicated that there is no significant difference among some environmental variables at the temporal level. The values of structural complexity and substrate composition indices showed that E4 had the highest values (0.8), followed by E1 (0.6), and E2 and E3 (0.4). Moreover, E4 had the highest richness and diversity, according to Hill’s number. The canonical correspondence analysis showed that the substrate, and the complexity and width of the river channel, had a significant influence on fish composition and distribution. The fish community richness and diversity did not change temporarily, but did spatially, which could be related to the different structural features of sampling sites.

scholarly journals Influence of environmental variables on stream fish fauna at multiple spatial scales

2016 ◽  
Vol 14 (3) ◽  
Author(s):  
Nara Tadini Junqueira ◽  
Diego Rodrigues Macedo ◽  
Rafael Couto Rosa de Souza ◽  
Robert Mason Hughes ◽  
Marcos Callisto ◽  
...  
Keyword(s):  
Land Use ◽  
River Basin ◽  
Fish Species ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Fish Fauna ◽  
Stream Fish ◽  
Fish Diversity ◽  
Physical Habitat

ABSTRACT Effects of environmental variables at different spatial scales on freshwater fish assemblages are relatively unexplored in Neotropical ecosystems. However, those influences are important for developing management strategies to conserve fish diversity and water resources. We evaluated the influences of site- (in-stream) and catchment-scale (land use and cover) environmental variables on the abundance and occurrence of fish species in streams of the Upper Araguari River basin through use of variance partitioning with partial CCA. We sampled 38 1st to 3rd order stream sites in September 2009. We quantified site variables to calculate 11 physical habitat metrics and mapped catchment land use/cover. Site and catchment variables explained > 50% of the total variation in fish species. Site variables (fish abundance: 25.31%; occurrence: 24.51%) explained slightly more variation in fish species than catchment land use/cover (abundance: 22.69%; occurrence: 18.90%), indicating that factors at both scales are important. Because anthropogenic pressures at site and catchment scales both affect stream fish in the Upper Araguari River basin, both must be considered jointly to apply conservation strategies in an efficient manner.

scholarly journals Short Communication: Fish diversity and its relationship with environmental variables in Kamala River, Nepal

2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Sumnima Ghimire ◽  
Narayan Koju
Keyword(s):  
Environmental Variables ◽  
Short Communication ◽  
Monsoon Season ◽  
Aquatic Organisms ◽  
Fish Diversity ◽  
Species Variation ◽  
Physiochemical Parameters ◽  
Fish Samples ◽  
Ordination Method ◽  
Baseline Information

Ghimire S, Koju NP. 2021. Short Communication: Fish diversity and its relationship with environmental variables in Kamala River, Nepal. Biodiversitas 22: 4865-4871. Kamala River originates from the lower part of the Mahabharat range and flows through inner to outer Terai, providing a broad range of ecosystem services; provisioning, regulating, supporting, and cultural. However, the information regarding the environmental factors and species diversity in the river is not available enough. Hence the study aimed to explore baseline information on the diversity and abundance of fish and their relation to environmental variables. The fish diversity was assessed in five sections of Kamala River and correlated with different environmental variables. The study was carried out during September- October 2019, marking the post-monsoon season of Nepal. Fish samples were collected using cast nets, and physiochemical parameters were analysed onsite and in the laboratory. Altogether 19 freshwater fish species belonging to 5 orders, 8 families, and 15 genera were recorded. Cyprinids were the most dominant in the river, while Channids, Mastacembelids, Botiids, Sisorids, Gobiids were represented less. The Redundancy Analysis (RDA) ordination method revealed that species variation was correlated with temperature, Electrical Conductivity (EC), Total Dissolved Solids (TDS), and nitrate. Nonetheless, different river sections were disturbed due to mining, deforestation, and construction activities, which could pose a real threat to fish diversity and population, and other aquatic organisms.

Landscape Influences on Stream Habitats and Biological Assemblages

2006 ◽  
Keyword(s):  
Land Cover ◽  
Ictalurus Punctatus ◽  
Environmental Variables ◽  
Agricultural Land ◽  
Fish Assemblages ◽  
Spatial Scales ◽  
Species Abundance ◽  
Ecological Condition ◽  
Basin Scale ◽  
Assemblage Metrics

<em>Abstract.</em>—We analyzed data from 38 sites on 31 large rivers in Wisconsin to characterize the influence of environmental variables at the basin, reach, and site scales on fish assemblages. Electrofishing and site habitat data were collected for a distance of 1.6 km per site. Environmental variables included conductivity, substrate, and fish cover at the site scale; distance to impoundments, dams, and length of riverine habitat at the reach scale; and land cover, climate, and geology at the basin scale. Of the 77 fish species found, 39 occurred in more than 10% of the sites and were retained for analyses of fish abundance and biomass. Redundancy analysis (RDA) was used to relate species abundance, biomass, and 16 assemblage metrics to environmental variables at the three spatial scales. The site and basin scales defined fishes along a gradient from high conductivity, fine substrate, and agricultural land cover to low conductivity, rocky substrate, and forested land cover. For abundance and biomass, the strongest assemblage pattern contrasted northern hog sucker <em>Hypentelium nigricans</em>, blackside darter <em>Percina maculata</em>, and logperch <em>P. caprodes </em>with common carp <em>Cyprinus carpio</em>, channel catfish <em>Ictalurus punctatus</em>, and sauger <em>Sander canadensis</em>. The <em>H. nigricans </em>group, along with high values of index of biotic integrity and some assemblage metrics (percent lithophilic spawners, percent round-bodied suckers), corresponded with the forested end of the ecological gradient, whereas the <em>C. carpio </em>group and percent anomalies corresponded with the agricultural end. Natural environmental conditions, including bedrock geology type, bedrock depth, surficial geology texture, basin area, and precipitation, also influenced the fish assemblage. Partial RDA procedures partitioned the explained variation among spatial scales and their interactions. We found that widespread land cover alterations at the basin scale were most strongly related to fish assemblages across our study area. Understanding the influence of environmental variables among multiple spatial scales on fish assemblages can improve our ability to assess the ecological condition of large river systems and subsequently target the appropriate scale for management or restoration efforts.

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 Effects of nutrients increase on the copepod community of a reservoir using cages

2015 ◽  
Vol 27 (3) ◽  
pp. 265-274 ◽  
Author(s):  
Vanessa Graciele Tibúrcio ◽  
Rodrigo Leite Arrieira ◽  
Leilane Talita Fatoreto Schwind ◽  
Claudia Costa Bonecker ◽  
Fábio Amodêo Lansac-Tôha
Keyword(s):  
Final Stage ◽  
Environmental Variables ◽  
Initial Conditions ◽  
Spatial Scales ◽  
Principal Component ◽  
Fish Farming ◽  
Nutrient Concentrations ◽  
System Productivity ◽  
Copepod Abundance ◽  
Significant Difference

Abstract Aim: This study investigated changes in copepod abundance and the influence of environmental variables in a reservoir with fish farming using cages, on temporal and spatial scales. We hypothesised that the copepod abundance will increase when influenced by changes in environmental variables due the increase of nutrients originating from fish farming. Methods A 120-day sampling of copepods and environmental variables was carried out in a subtropical reservoir of the Paraná River basin (Rosana reservoir), upstream and downstream of three sets of cages with different fish stocking densities. A Principal Component Analysis was conducted to characterise sampling periods and points through environmental variables. The differences between copepod abundance according to sampling periods and points were tested by ANOVA. Results We observed higher maximum values for most nutrient concentrations and dissolved oxygen in the final stage of the experiment and in the location of cages installation. The copepod abundance increased sharply during the first days of the experiment and then decreased during the following periods with a tendency towards returning to the initial conditions at the final stage of the experiment. A significant difference in copepod abundance between the location of cages installation and downstream was showed. In addition, turbidity, chlorophyll-a, and nitrate significantly predicted copepod abundance. Conclusion The results suggested that the changes in copepod abundance over time are influenced by environmental variables, evidenced by the increase in nutrient concentration after the cage installation, related to the increase in the practice of fish farming. The environmental variables related to system productivity were linked to the availability of food resources. Thus, our hypothesis that copepod abundance is increased due the alterations in environmental variables caused by the increase in the practice of fish farming using cages was corroborated.

Fish assemblages in floodplain lakes in a Neotropical river during the wet season (Magdalena River, Colombia)

2012 ◽  
Vol 28 (3) ◽  
pp. 271-279 ◽  
Author(s):  
Carlos Granado-Lorencio ◽  
Alejandra Gulfo ◽  
Frank Alvarez ◽  
Luz Fernanda Jiménez-Segura ◽  
Juan David Carvajal-Quintero ◽  
...  
Keyword(s):  
Species Richness ◽  
Fish Assemblages ◽  
Abiotic Factors ◽  
Environmental Parameters ◽  
Floodplain Lakes ◽  
Fish Diversity ◽  
Wet Season ◽  
River Floodplain ◽  
Lake Morphology ◽  
Magdalena River

Abstract:A number of studies have pointed out that abiotic factors and recolonization dynamics appear to be more important than biotic interactions in structuring river–fish assemblages. In this paper, we studied the fish assemblages in 27 floodplain lakes, with perennial connection to the river, in the middle section of the Magdalena River (Colombia), to examine spatial pattern in freshwater fish diversity in relation to some environmental parameters. Our objective was to examine relationships between floodplain-lake fish communities and environmental variables associated with lake morphology, water chemistry and river–floodplain connectivity in a large river–floodplain ecosystem. During the study, a total of 18 237 fish were caught from 50 species (regional richness; 17 were migrants and 33 residents). In the present study, the most diverse order was Characiformes with 20 species, followed by Siluriformes, with 19 species. Characidae and Loricaridae were the richest families. The range of species richness (local richness) varied between five and 39 species. Similarity of local assemblages (using the presence–absence data) depends on the distance between lakes. A positive relationship was observed between the Ln of the total abundance of each species and the number of lakes where they were found. Out of all the environmental parameters taken in the lakes, only the size (Log Area) and relative perimeter length are significantly related to local assemblage species richness. It has not been possible to demonstrate that the connectivity (distance) from lakes to the main river can be considered a predictor of the local richness.

scholarly journals Environmental Variables and Fisheries Diversity of the Nuwa River, Panchthar, Nepal

2020 ◽  
Vol 13 (13) ◽  
pp. 69-74
Author(s):  
Jash Hang Limbu ◽  
Archana Prasad
Keyword(s):  
Dissolved Oxygen ◽  
Fish Species ◽  
Environmental Variables ◽  
Diversity Index ◽  
Environmental Parameters ◽  
Influential Factors ◽  
Water Volume ◽  
Fish Diversity ◽  
Fish Assemblage Structure ◽  
Fish Samples

The fish samples were collected from October 2017 to June 2018 in Nuwa River from four sampling stations by using cast net, bamboo fish trap and mosquito nets. Environmental parameters: water temperature, dissolved Oxygen (DO), CO2, pH, hardness and water velocity were analyzed during each field visit. Eight fish species were collected in present study. The most copious species were Schizothorax plagiostomus, and Schistura multifaciatus. Shannon-Weiner fish diversity index and species richness recorded were highest at station I and lowest at station III, similarly, evenness index was highest at station I and lowest at station III. The water volume, water depth, and the availability of substrates were found to be major influential factors for the weight and length of the fishes. The redundancy analysis (RDA) portrayed that environmental variables like dissolved oxygen, free- carbon dioxide, and pH were found to be pivotal variables to shape the fish assemblage structure of Nuwa River. The cluster analysis delineated that similarity between fish species subsided as the distance of sites turgid.

scholarly journals Factors determining the structure of fish assemblages in Tarumã River, Jaru Biological Reserve, Machado River drainage, northern Brazil

2021 ◽  
Vol 19 (4) ◽  
Author(s):  
Igor D. Costa ◽  
Natalia N. Santos Nunes ◽  
Carlos E. C. Freitas
Keyword(s):  
Species Composition ◽  
Environmental Variables ◽  
Fish Assemblages ◽  
Hydrological Cycle ◽  
Principal Component ◽  
High Water ◽  
Environmental Data ◽  
Partial Redundancy Analysis ◽  
The Individual ◽  
Biological Reserve

ABSTRACT Few studies on fish assemblages and relations with environmental factors in aquatic systems in southeastern Amazonia have been carried out when compared to other areas in the Amazon. Therefore, which are the main environmental variables and processes responsible for structuring them remains unknown. We hypothesized that fish assemblages respond the variation in the physical-chemistry variables between seasons of the hydrological cycle in a pristine river in the Amazon. The study was performed on fish assemblages of the Tarumã River, Jaru Biological Reserve, Rondônia. Samplings were carried out in five sites along the river in March and September, 2015, which included fish collection and environmental data measurements. Principal component analysis was performed to ordinate the sites in high water and low water seasons, according to environmental variables. We used a similarity analysis in order to identify the individual contribution of species in hydrological period and a partial redundancy analysis for quantify the relative importance of environmental variables in the species composition. As predicted by our hypothesis, the species composition was influenced by dissolved oxygen and temperature. Myloplus rubripinnis, Serrasalmus compressus, and S. rhombeus were the most abundant during high water, while S. rhombeus, Myloplus lobatus, Prochilodus nigricans, and Hydrolycus armatus were the dominant species during the low water.

scholarly journals Abundance and composition of Rotifera in an abandoned meander lake (Lago Amapá) in Rio Branco, Acre, Brazil

2004 ◽  
Vol 21 (2) ◽  
pp. 233-241 ◽  
Author(s):  
Erlei Cassiano Keppeler ◽  
Elsa Rodrigues Hardy
Keyword(s):  
Electrical Conductivity ◽  
Seasonal Changes ◽  
Environmental Variables ◽  
High Water ◽  
Water Levels ◽  
Water Phase ◽  
Seasonal Differences ◽  
Animal Group ◽  
Rotifer Community ◽  
Significant Difference

The rotifer community in Lago Amapá (abandoned meander lake of the Rio Acre floodplain) was investigated with respect to seasonal changes. Sampling was performed at three collection stations, generally weekly, during the dry season between May 8, 1997 and October 31, 1997, and during the rainy season between January 2, 1998 and February 24, 1998. The density and composition of rotifer species (48 taxons of rotifers) were determined, and their diversity and abundance were observed to be greater, respectively, at high-water and low-water. Anova was performed, by means of the F test, to test for seasonal differences in environmental variables and rotifers, showing that there was a highly statistically significant difference for pH and transparency (p < 0.01). Pearson's correlation was used to show that rotifer numbers during the low-water phase correlated negatively with electrical conductivity (r = -0.8824, p < 0.05) and during the high-water phase correlated negatively with depth (r = -0.7513, p < 0.05). Seasonal changes, caused by an increase in water levels and the low diversification of niches, influenced the composition and abundance of the animal group studied.

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