scholarly journals Seasonal variation and community structure of fishes in the Mahananda River with special reference to conservation issues

2016 ◽  
Vol 4 (1) ◽  
pp. 325 ◽  
Author(s):  
Shams Muhammad Galib ◽  
Md Abdur Rashid ◽  
Nipa Chaki ◽  
ABM Mohsin ◽  
Md Abdur Razzaq Joadder
Keyword(s):  
Community Structure ◽  
Seasonal Variation ◽  
Fish Species ◽  
Legal Protection ◽  
Hypophthalmichthys Molitrix ◽  
Exotic Fish ◽  
Meristic Characters ◽  
Analysis Of Similarity ◽  
Fishing Gears ◽  
Traditional Fishing

This study was carried out in the Mahananda River from January to December 2013 with a view to determining the seasonal variation and community structure of fishes along with some conservation issues. Monthly sampling was carried out using traditional fishing gears and fishes were identified based on morphometric and meristic characters. A total of 4082 individuals of native fish species were captured, analyzed and classified into 62 species belonging to 46 genera, 25 families and 9 orders. Cypriniformes and Siluriformes were the dominant fish orders represented by 19 species each and the most abundant family was Cyprinidae (14 species). In addition to indigenous individuals, 9 individuals of 2 exotic fish species (Hypophthalmichthys molitrix and Pangasius hypophthalmus) were also recorded. Among three sampling sites, S-1 was the most diversified in terms of not only the number of individual fish but also the number of species present represented by mean (±SE) individuals of 151.50±25.22 and species of 25.58±3.91. Three distinct fish groups of fish families were revealed from the cluster analysis of similarity. To improve the situation, control of illegal fishing gears, establishment of sanctuaries and legal protection for threatened species are recommended.

scholarly journals Effect of the Human Utilization of Northern Snakehead (Channa argus Cantor, 1842) on the Settlement of Exotic Fish and Cladoceran Community Structure

2021 ◽  
Vol 13 (5) ◽  
pp. 2486
Author(s):  
Jong-Yun Choi ◽  
Seong-Ki Kim
Keyword(s):  
Community Structure ◽  
Fish Species ◽  
Micropterus Salmoides ◽  
Lepomis Macrochirus ◽  
Nakdong River ◽  
Exotic Fish ◽  
Carnivorous Fish ◽  
Channa Argus ◽  
The Nakdong River ◽  
Exotic Fish Species

Empirical studies suggest that changes in the density of top predators, such as carnivorous fish, in freshwater food webs, strongly affect not only fish communities but also various primary and secondary consumers. Based on these findings, we explored how differences in the utilization of carnivorous fish (i.e., Northern Snakehead, Channa argus) by humans affected the fish and cladoceran community structure as well as the settlement of exotic fish species (i.e., Lepomis macrochirus and Micropterus salmoides) in 30 wetlands located in the upper and lower reaches of the Nakdong River. Our results show that in the mid–lower reaches of the Nakdong River, the density of C. argus was low, while high densities of L. macrochirus and M. salmoides were observed. Exotic fish species are frequently consumed by C. argus, leading to a low density of L. macrochirus and M. salmoides in the upper reaches, which supported a high density of C. argus. However, in the mid–lower reaches, the density of L. macrochirus was high because of the frequent collection of C. argus by fishing activities. The dominance of L. macrochirus significantly changed the structure of cladoceran communities. L. macrochirus mainly feeds on pelagic species, increasing the density of epiphytic species in the mid–lower reaches. The continued utilization of C. argus by humans induced a stable settlement of exotic fish species and strongly affected the community structures of primary consumers in the 30 wetlands. The frequency of C. argus collection has to be reduced to secure biodiversity in the mid–lower reaches of the Nakdong River, which will reduce the proportion of exotic fish species and increase the conservation of native fish.

scholarly journals Diet and niche breadth and overlap in fish communities within the area affected by an Amazonian reservoir (Amapá, Brazil)

2014 ◽  
Vol 86 (1) ◽  
pp. 383-406 ◽  
Author(s):  
JÚLIO C. SÁ-OLIVEIRA ◽  
RONALDO ANGELINI ◽  
VICTORIA J. ISAAC-NAHUM
Keyword(s):  
Community Structure ◽  
Seasonal Variation ◽  
Fish Species ◽  
Niche Breadth ◽  
Null Model ◽  
Stomach Contents ◽  
Physical Conditions ◽  
River Damming ◽  
Standard Configuration ◽  
Feeding Resources

We investigated the niche breadth and overlap of the fish species occurring in four environments affected by the Coaracy Nunes reservoir, in the Amapá Brazilian State. Seasonal samples of fishes were taken using a standard configuration of gillnets, as well as dragnets, lines, and castnets. Five hundred and forty stomach contents, representing 47 fish species were analyzed and quantified. Niche breadth and overlap were estimated using indexes of Levins and Pianka, respectively, while interspecific competition was evaluated using a null model (RA3). ANOVA and the KruskalWallis test were used, respectively, to evaluate differences in niche breadth and overlap between areas. The data indicate that the majority of the fish species belong to the piscivore, omnivore, and detritivore guilds. These species have likely colonized the environments due to the availability of suitable feeding resources, and the favorable physical conditions created by the river damming. Overall, few species have ample niches, but most of them are highly specialized. Resources seasonal variation had little effect on the feeding behavior of most species in the study areas. The null models indicated that competition was not a factor determining on community structure.

scholarly journals Biometric relationships of the Fat sleeper Dormitator maculatus (Blotch, 1792) (Teleostei: Eleotridae) from Alvarado lagoon, Veracruz, Mexico

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Jonathan Franco-López ◽  
Luis Gerardo Abarca-Arenas ◽  
Edgar Peláez-Rodríguez ◽  
José Luis Viveros-Legorreta ◽  
Adrian Felipe González-Acosta
Keyword(s):  
Fish Species ◽  
Fishery Management ◽  
Study Report ◽  
Fishing Gears ◽  
Sustainable Fishery ◽  
Traditional Fishing ◽  
First Time

L-W and eight biometric relationships for D. maculatus in the Alvarado lagoon, were performed on 500 specimens (252 females and 248 males), 23.7 - 143.9 cm TL and 0.95 – 59.1 g weight, sampled during May 2015 to May 2017, using traditional fishing gears. The b coefficient indicated isometric growth (b = 3.0195; r2 >0.9763; P < 0.05) for overall sample, females (b = 3.0507; r2 >0.989; P < 0.05) and males (b = 2.9953; r2 >0.9783 P < 0.05). Biometric relationships showed high correlations (r2 >0.9193 – 0.9992; P < 0.05) for the overall sample. females (r2 >0.9188 – 0.9981; P < 0.05) and males (r2 >0.9079 – 0.9995; P < 0.05). This study report for the first time L-W and biometric relationships for the Fat sleeper. These results will be useful to delineate a baseline for regulations and the sustainable fishery management of this fish species

scholarly journals Fish Diversity and Its Threatened Status of the Dharla River in Bangladesh

2021 ◽  
Vol 79 (4) ◽  
pp. 163-172
Author(s):  
Md. Ashraful Alam ◽  
Yeasmin Ara ◽  
Imran Parvez ◽  
Jayanto Kumar Roy ◽  
Macksood Alam Khan
Keyword(s):  
Fish Species ◽  
Diversity Indices ◽  
Fish Diversity ◽  
Indigenous Species ◽  
Local Data ◽  
Exotic Fish ◽  
Fish Biodiversity ◽  
Fishing Gears ◽  
Threatened Status ◽  
Destructive Fishing

Abstract Fish diversity of a riverine ecosystem became reduced due to different manmade and natural calamities. This study investigated the present fish biodiversity status of the Dharla River located (25.8103° N, 89.6487° E) in the northern part of Bangladesh from January to December 2018. In this study, the existing fish biodiversity status of the Dharla River was estimated in terms of diversity indices and threatened status (both global and local). Data was collected from the three sampling sites of the river using different fishing gears and three selected fish markets located in the Kurigram district of Bangladesh. A total of 76 fish species were identified belonging to 8 orders, 26 families and 57 genera. The Cyprinidae was the most dominant family represented by 14 species followed by the Danionidae (13 species), Bagridae (8 species) and few minor families. Apart from the indigenous species, nine exotic fish species were also recorded. The Shannon-Weaver diversity (H), Pielous evenness (e) and Margalef richness (D) indices ranged from 3.00 to 3.71, 0.62 to 0.94 and 3.94 to 7.95, respectively. Out of 76 indigenous species, 28 species (37%) were identified as threatened in Bangladesh, which included critically endangered (4), vulnerable (9) and endangered (15) species. Indiscriminate fishing through poisoning and destructive fishing gears were identified as the major threats to fish biodiversity of the Dharla River. Thus, the river serves as considerable support for threatened indigenous fishes. Therefore, necessary steps are needed to stop destructive fishing, establish permanent fish sanctuaries and proper monitoring for maintaining sustainable biodiversity in the Dharla River.

scholarly journals Status of threaten fish species in Narsunda river

2018 ◽  
Vol 5 (2) ◽  
pp. 259-268
Author(s):  
Fahimul Arefin ◽  
Md Moniruzzaman ◽  
Saymuna Tarin Lupa ◽  
Md Ashikur Rahman ◽  
Ariful Islam ◽  
...  
Keyword(s):  
Endangered Species ◽  
Fish Species ◽  
Threatened Fish ◽  
Exotic Fish ◽  
Critically Endangered Species ◽  
Time Period ◽  
Fishing Gears ◽  
Management And Conservation ◽  
Day By Day ◽  
Exotic Fish Species

To identify the threatened fish species and focus on fish biodiversity conservation in the Narsunda River Kishoreganj Sadar, Kishoreganj district, the present study was conducted for a time period of 6 months (April-November, 2012). A total of 23 threatened fish species were identified in the river among them, 9 vulnerable, 11 endangered and 3 critically endangered species as well as 8 exotic fish species were also found in the River. The fishing gears used by the fishermen in Narsunda River includes 4 types of nets, 3 types of traps, 3 hooks and lines and 2 types of wounding gears whereas major fishing craft and gears were mainly wooden boat and seine net (locally called ‘ber jal’) respectively. Due to environmental degradation and manmade causes the biodiversity of this river decreasing day by day and it could be minimized by proper management and conservation techniques.Res. Agric., Livest. Fish.5(2): 259-268, August 2018

scholarly journals Seasonal feeding plasticity can facilitate coexistence of dominant omnivores in Neotropical streams

2021 ◽  
Author(s):  
Mayara P. Neves ◽  
Pavel Kratina ◽  
Rosilene L. Delariva ◽  
J. Iwan Jones ◽  
Clarice B. Fialho
Keyword(s):  
Seasonal Variation ◽  
Fish Species ◽  
Resource Availability ◽  
Seasonal Changes ◽  
Dry Season ◽  
Diet Overlap ◽  
Isotopic Niche ◽  
Neotropical Streams ◽  
Feeding Plasticity ◽  
The Impact

AbstractCoexistence of ecomorphologically similar species in diverse Neotropical ecosystems has been a focus of long-term debate among ecologists and evolutionary biologists. Such coexistence can be promoted by trophic plasticity and seasonal changes in omnivorous feeding. We combined stomach content and stable isotope analyses to determine how seasonal variation in resource availability influences the consumption and assimilation of resources by two syntopic fish species, Psalidodon aff. gymnodontus and P. bifasciatus, in the Lower Iguaçu basin. We also tested the impact of seasonality on trophic niche breadth and diet overlap of these two dominant omnivores. Seasonal changes in resource availability strongly influenced the consumption and assimilation of resources by the two fish species. Both species exhibited high levels of omnivory, characterized by high diversity of allochthonous resources in the wet season. Terrestrial invertebrates were the main component of diet during this season. However, in the dry season, both species reduced their isotopic niches, indicating diet specialization. High diet overlap was observed in both seasons, but the isotopic niche overlap was smaller in the dry season. Substantial reduction in the isotopic niche of P. bifascistus and a shift toward aquatic invertebrates can facilitate coexistence during this season of resource shortage. Feeding plasticity allows omnivorous fish to adjust their trophic niches according to seasonality, promoting the exploitation of different resources during periods of greater resource diversity. This seasonal variation could be an important mechanism that contributes to the resource partitioning and coexistence of dominant omnivores in Neotropical streams.

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