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

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 11.5Â°C in January to 31.02Â°C in August month, dissolved oxygen ranged from 2.24 mg/l in September to 9.9mg/l in February, salinity varied from 1.37â€° in November to 3.76â€° 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).

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The role of emergent physical and chemical properties of Florida springs in predicting fish assemblage structure

Freshwater Science ◽

10.1086/716102 ◽

2021 ◽

Author(s):

Kirsten Work

Keyword(s):

Fish Assemblage ◽

Chemical Properties ◽

Assemblage Structure ◽

Fish Assemblage Structure ◽

Physical And Chemical Properties ◽

Physical And Chemical ◽

Florida Springs ◽

And Chemical Properties

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Longitudinal patterns in distribution of native and non-native fish species in a regulated temperate Neotropical river

Acta Limnologica Brasiliensia ◽

10.1590/s2179-975x11519 ◽

2021 ◽

Vol 33 ◽

Author(s):

Andrea Bertora ◽

Fabián Grosman ◽

Pablo Sanzano ◽

Juan José Rosso

Keyword(s):

Dissolved Oxygen ◽

Fish Species ◽

Environmental Conditions ◽

Fish Assemblage ◽

Native Species ◽

Assemblage Structure ◽

Native Fish ◽

Fish Assemblage Structure ◽

Longitudinal Patterns ◽

Tolerant Species

Abstract: Aim We evaluated the longitudinal patterns in distribution of native and non-native fish species in a hydrologically fragmented and environmentally variable lowland temperate river. Methods Four sites representing contrasting habitat and environmental conditions were sampled: a clear water reservoir, a turbid water lagoon and two river reaches with clear and turbid waters each. Environmental variables were measured in situ and in the laboratory. Fishes were sampled using trammel and beach seine nets. Results Two main environmental scenarios were identified: the upstream reaches, with colder, clearer and nutrient-oxygen poor waters (reservoir and its downstream river) and the downstream reaches, where turbidity, dissolved oxygen, water temperature, conductivity and nutrients largely increased (lagoon and its downstream river). Fourteen species with a high non-native/native (4:10) ratio were collected. Non-native species (NNS) were confined to lentic conditions, where the silverside Odontesthes bonariensis dominated. Native species (NS) better thrive in lotic conditions where the turbid scenario further favored tolerant species. Environmental conditions also seemed to influence the distribution of NNS. Fish assemblage structure considering either, all species, NNS or NS significantly differed among sampled reaches and habitat (lentic-lotic) conditions. Total fish abundance was higher in lentic reaches. Species richness and diversity were favored by the turbid scenario. Beta diversity was mostly explained by the replacement component revealing the substitution of species as the main pattern of variation. Water conductivity, nitrates and dissolved oxygen were the most important predictor variables in the best and most frequent explanatory models of fish assemblage structures. Conclusions Our results revealed that a low diversified Neotropical fish fauna is disrupted by habitat fragmentation due to the creation of artificial impoundments and the introduction of NNS. Environmental conditions further modulate the fish assemblage structure by affecting the distribution of species where tolerant species were favored by turbid, nutrient-rich waters with higher conductivity and pH.

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Conservation biogeography of lotic fishes in the Missouri and Colorado River basins

10.32469/10355/69974 ◽

2019 ◽

Author(s):

◽

Landon Lee Pierce

Keyword(s):

Species Distribution ◽

Fish Assemblage ◽

Native Species ◽

Species Distribution Models ◽

Colorado River ◽

River Basins ◽

Assemblage Structure ◽

Native Fish ◽

Fish Assemblage Structure ◽

Distribution Models

To improve our understanding of lotic fish ecology and improve conservation efforts, I 1) identified potentially ecologically important tributaries (PEITs) and evaluated their effects on fish assemble structure, 2) evaluated factors affecting spatial transferability of species distribution models (SDMs), and 3) evaluated the drivers of non-native fish establishment in the Missouri and Colorado River basins (MRB and CRB). The effects of PEIT likely vary among rivers as all Missouri River PEITs affected fish assemblage structure, but only half of upper Colorado River basin PEITs affected fish assemblage structure. Species distribution models transferred from the MRB to the CRB for 15 of 25 species, but transferability was not predictable based on species characteristics, re-enforcing the hypothesis that transferability is species-and contextspecific. Support for Human Activity, Biotic Resistance and Biotic Acceptance hypotheses as the drivers of non-native fish establishment varied by family, but these hypotheses rarely explained significant variability in the probability of non-native Salmonidae, Catostomidae, and Cyprinidae occurrence. These results may suggest that other factors (e.g., natural factors) drive non-native species distributions at the spatial (i.e., grain-stream segment; extents-physiographic divisions, and MRB and CRB combined) and taxonomic (i.e., family) scales considered in this study. This study aids conservations efforts by providing an efficient approach for identifying ecologically important tributaries and improving predictions of non-native species establishment.

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

Our Nature ◽

10.3126/on.v18i1.34239 ◽

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.

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