Fish Diversity and Water Quality Parameters of Mechi River, Jhapa, Province No. 1, Nepal

Abstract

Species diversity is widely recognised as an important trait of functioning and resilient ecosystem. Spatio-temporal patterns of fish community structure in the Mechi River was studied based on stratified random survey, conducted between September 2018 and April 2019. The survey was conducted at three different sampling stations in three different seasons. For the fish sampling, two cast nets of different sizes were used, one having large mesh size of 0.5 cm, 3 m diameter and 2 kg weight and another having mesh size of 2 cm, 6 m diameter and 6 kg weight. In addition, drag net and gill net were also used to collect the fish samples. A total of 1,772 fishes belonging to 4 orders, 8 families, 16 genera and 33 species were documented. The results from the similarity percentage analysis indicated that, the species Schistura devdevi, Brachydanio rerio, Puntius sophore, Barilius barila, Schistura beveani and Puntius terio were the most copious fish species recorded from the Mechi River. One-way analysis of similarity testing for space and time variations in fish community indicated that there was a significant difference in space (R = 0.66, p<0.01) but no significant difference in time (R = -0.0123, p>0.433). The Canonical Correspondence Analysis hinted that dissolved oxygen, water velocity and pH have shown to influence the fish assemblage structure in Mechi River.

Evaluating the influence of environmental variables on fish abundance and distribution in the Singhiya River of Morang District, eastern Nepal

“…This suggests that the Singhiya River provides a significant source of livelihood and food to local fisherman and communities. The representation of Cypriniformes, Siluriformes, and Anabantiformes orders found in this study is consistent with the information reported in the other river systems of Nepal such as the Mechi River (Adhikari et al 2021), Ratuwa River (Rajbanshi et al 2021), and Phewa Khola (Limbu et al 2021b).…”

“…In the current study, water velocity, water temperature, total alkalinity, pH, and total hardness are the major influencing factors (P <0.05) to determine the fish diversity, abundance, and distribution of the Singhiya River. Water velocity (Yu & Lee 2002;Yan et al 2010;Adhikari et al 2021), water temperature (Kadye et al 2008;Temesgen et al 2021), total alkalinity (Edds 1993;Pokharel et al 2018), pH (Pokharel et al 2018;Limbu et al 2021b;Rajbanshi et al 2021), and total hardness (Rajbanshi et al 2021;Shrestha et al 2021) have also been found to be influencing factors to shape the fish assemblage structure.…”

“…The factors influencing fish assemblages involve the environmental variables which are spatially heterogeneous and temporally variable and biotic interactions such as competition and predation (Harvey & Stewart 1991;Grossman et al 1998). The environmental variables such as water velocity (Li et al 2012;Adhikari et al 2021;Limbu et al 2021b), water depth (Kadye et al 2008;Li et al 2012;Mia et al 2019;Chaudhary & Limbu 2021), substrate (Vlach et al 2005;Yan et al 2010), water temperature (Hossain et al 2012;Nsor & Obodai 2016), and dissolved oxygen (Guo et al 2018) all have been found to affect fish abundance and distribution in the rivers and streams.…”

Fecundity and Gonadosomatic Index of Sucker Throat Catfish, Pseudecheneis sulcata (McClelland, 1842) from the Snow-fed Tamor River in Eastern Nepal

“…The human-induced activities like electrofishing, poisoning of river, mass fishing, detonation in the name of economics and fun had become serious threat to the population of P. sulcata and whole fish diversity of Tamor River. Moreover, ongoing road development, microhydropower generation, the use of poisonous herbicides, illegal electro-fishing, deforestation and water diversion are all found to be major threats to the present fish species of Nepal's rivers, stream, ponds, lakes and reservoir (Limbu et al, 2020;2021). Therefore, for the better monitor, management and conservation of Nepal's indigenous fish species, habitat rehabilitation, and construction of fish ladders/passage are needed.…”

“…Human activities, fishing pressure, climate change, ongoing road building, micro-hydropower generation, the use of herbicides, electro-fishing, deforestation, and water diversion have all contributed to the decline of several Nepalese fisheries populations (Adhikari et al, 2021;Limbu et al, 2021a). Moreover, mostly in the hill side of Nepal, ongoing road evelopment is found to be major threat to the present fish species such as Pseudecheneis spp., Garra spp., Schizothorax spp., Shistura spp.…”