Fecundity, histomorphology of the ovary and size at first maturity of Neolissochilus hexagonolepis (McClelland) in Tamor River, Nepal

Neolissochilus hexagonolepis (McClelland, 1839) is one among the notable species in snow-fed torrential rivers of Nepal. The present study attempts to investigate some reproductive traits of N. hexagonolepis, including the length at first maturity, fecundity and its relationships with biometric variables like lengths (TL, SL, and FL) and weights (TW and OW) of the fish in the mid-reaches of Tamor River, Nepal. A total of 109 fish samples were collected from the river. For each individual, total length (TL), standard length (SL) and fork length (FL) were measured in a fully stretched condition to the nearest 1mm using a measuring tape and graduated ruler, while total weight (TW) and ovary weight (OW) was measured using a digital balance with the precision of 0.01 g. The mean absolute fecundity (F) was 8356.44 ± 4612.59 and ranged from 2398.6 to 20160. SL was more significantly correlated with absolute fecundity (R2=0.59; p<0.001) than other body metrics. The results showed that female individuals of N. hexagonolepis attained the first sexual maturity at TL 32.9 cm. N. hexagonolepis exhibited a protracted breeding period with its ovaries passing through six different stages of maturation. The finding of the present study may serve as a protocol for fishery biologists and managers to promulgate adequate regulations for continual fishery management in the River Tamor, Nepal

Diversity of Mammalian Fauna and Conservation Issues of Dhankuta Municipality of Dhankuta District, Nepal

Dhankuta municipality is a mid-hill town in Dhankuta district, Province 1, Nepal. The municipality consists of 10 wards scattered across 111.6 square kilometers of geographical area and is situated between 26°59’59’’ and 27°02’55’’ north latitude and 87°17’52’’ and 87°23’09’’ east longitudes. Mammalian diversity in the municipality has not been so far recorded. The present study was conducted from August 2021 to July 2022 with a view to bridging this knowledge deficit and presenting an up-to-date account of the mammalian species in the agricultural fields and forests of the municipality based on questionnaire survey, direct sightings and indirect evidence. A total of 19 mammal species belonging to 7 orders and 13 families were registered. Among 19 species, 6 species belonged to Carnivora, 2 species to Cetartiodactyla, 3 species of Primate, 5 species to Rodentia and 1 each to Chiroptera, Eulipotypha, Lagomorpha. The major threats to mammalian fauna of the municipality include habitat loss and degradation, persecution, human-wildlife conflict and poaching. For long-term conservation of wild mammals more research is needed on their population genetics, habitat ecology, food web and climate change vulnerability. The information contained in the present study is expected to form the baseline for further development and research in the field of mammalian conservation in the municipality.</jats:p

Fecundity, histomorphology of the ovary and size at first maturity of Neolissochilus hexagonolepis (McClelland) in Tamor River, Nepal

Neolissochilus hexagonolepis (McClelland, 1839) is one among the notable species in snow-fed torrential rivers of Nepal. The present study attempts to investigate some reproductive traits of N. hexagonolepis, including the length at first maturity, fecundity and its relationships with biometric variables like lengths (TL, SL, and FL) and weights (TW and OW) of the fish in the mid-reaches of Tamor River, Nepal. A total of 109 fish samples were collected from the river. For each individual, total length (TL), standard length (SL) and fork length (FL) were measured in a fully stretched condition to the nearest 1mm using a measuring tape and graduated ruler, while total weight (TW) and ovary weight (OW) was measured using a digital balance with the precision of 0.01 g. The mean absolute fecundity (F) was 8356.44 ± 4612.59 and ranged from 2398.6 to 20160. SL was more significantly correlated with absolute fecundity (R2=0.59; p&lt;0.001) than other body metrics. The results showed that female individuals of N. hexagonolepis attained the first sexual maturity at TL 32.9 cm. N. hexagonolepis exhibited a protracted breeding period with its ovaries passing through six different stages of maturation. The finding of the present study may serve as a protocol for fishery biologists and managers to promulgate adequate regulations for continual fishery management in the River Tamor, Nepal.</jats:p

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

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.</jats:p