Our Nature https://www.nepjol.info/index.php/ON <p><em>Our Nature</em> is the journal brought out by the Nature Conservation and Health Care Council. <em>Our Nature</em> places a special emphasis on research papers, miscellaneous notes, and book review in all fields of biological sciences. It also includes papers in the general fields of theoretical, experimental and descriptive ecology and environmental science.</p> Nature Conservation and Health Care Council en-US Our Nature 1991-2951 Roles of Cooperatives in Fish Farming Development in Chitwan and Nawalparasi Susta East Districts https://www.nepjol.info/index.php/ON/article/view/34236 <p>A study was conducted to assess the role of cooperatives in improving fish farming through a comparison of fish farmers engaged and not engaged in cooperatives. Altogether, 140 fish farmers were selected from Chitwan and Nawalparasi Susta East district, 70 from each district. Annual income from fish production and annual total income was found significantly higher (p&lt;0.05) in non-cooperative fish farmers than cooperative fish farmers in Nawalparasi Susta East. The latter district has more fish farmers that have large-scale commercial operations. Fish farmers in cooperatives are mostly small-holders, whose production is consumed domestically. Non-cooperative fish farmers faced more (P&gt;0.05) challenges than cooperative farmers especially in terms of seed quality and quantity.&nbsp; Cooperatives were attractive for their support in saving and micro-finance schemes. The study advocates for increased support to establishment of cooperatives as they have great potential to develop fish farming sustainably and to empower their members socially and economically.</p> Sabina Rajthala Sunila Rai Dilip K. Jha Jay Dev Bista Roseanna Avento Copyright (c) 2021 Sabina Rajthala, Sunila Rai, Dilip K. Jha, Jay Dev Bista, Roseanna Avento 2020-12-30 2020-12-30 18 1 1 9 10.3126/on.v18i1.34236 The morphohistology and fine anatomy of the olfactory organ in pabda catfish, Ompok bimaculatus (Bloch, 1794) https://www.nepjol.info/index.php/ON/article/view/34237 <p>The organization of the olfactory system in <em>Ompok bimaculatus</em> (Siluriformes: Siluridae) were investigated by histological and ultrastructural analysis. The nasal chamber was totally engrossed by a boat shaped elongated olfactory rosette with numerous lamella. Histomicroscopically, each lamella was comprised of central core bounded on both sides by the cellular elements of olfactory epithelium. The central core was composed of thick connective tissue, nerve fibres and blood capillaries. The cellular components of the olfactory epithelium were identified based on their staining vigour, architecture, structural characteristics and surface features. The sensory epithelium contained morphologically recognizable ciliated, microvillous and rod receptor neurons. Labyrinth cells, scattered lymphatic cells, secretory mucous cells, stratified epithelial cells bearing microfolds and condensed ciliated supporting cells were observed in the indifferent epithelia. The basal cells were submerged in the deeper zone of mucosa above the basal lamina. &nbsp;Different sensory and nonsensory cells of the olfactory lining were associated with chemical stimulation of the fish studied. This species acquires a well developed olfactory sense for exploring the aquatic environment and able to determine the chemical changes in the surroundings.</p> Saroj Kumar Ghosh Copyright (c) 2021 Saroj Kumar Ghosh 2020-12-30 2020-12-30 18 1 10 15 10.3126/on.v18i1.34237 Singing patterns of the Oriental Magpie Robin Copsychus saularis Linn. https://www.nepjol.info/index.php/ON/article/view/34238 <p>Oriental Magpie Robin is a song bird that resides in some tropical regions of Asia. The present work was attempted to provide a detailed study of the territorial singing of this species in the area of Biratnagar (Nepal). Songs of Oriental Magpie Robin was recorded by using a digital voice recorder (Olympus VN-8700PC) for one hour without break at seven selected sites in Biratnagar. Recorded songs were converted in the form of spectrogram by using avisoft. Seven Oriental Magpie Robins, belonging to seven different study sites of Biratnagar were taken as subjects and have been abbreviated as Bird A, B, C, D, E, F and G respectively. It was very surprising that there was not even a single motif which was matching among any of the birds. Out of 1782 song samples recorded from seven individuals, 328 types of songs were identified. These songs were composed of 3 to 18 types of elements.</p> J. Karna B. R. Subba H. Bhattacharya D. T. Chhetry Copyright (c) 2021 J. Karna, B. R. Subba, H. Bhattacharya, D. T. Chhetry 2020-12-30 2020-12-30 18 1 16 27 10.3126/on.v18i1.34238 Fish Assemblage Structure and Environmental Correlates in Nepal’s West Rapti River, Banke https://www.nepjol.info/index.php/ON/article/view/34239 <p>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<strong>. </strong>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 <em>Cabdio morar </em>(C14, 13.63%), <em>Barilius bendelensis </em>(C11, 10.32%), <em>Gogangra viridescens </em>(C22, 7.85%), <em>Salmostoma phulo </em>(C17, 7.74%), <em>Labeo gonius </em>(C5, 7.53%), <em>Gagata cenia </em>(C23, 6.45%), <em>Garra gotyla </em>(C6, 5.87%) and <em>Labeo dyocelius </em>(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.</p> Sujata Chaudhary Jash Hang Limbu Suren Subba Jeevan Kumar Gurung Naresh Pandey K. Deepak Singh Copyright (c) 2021 Sujata Chaudhary, Jash Hang Limbu, Suren Subba, Jeevan Kumar Gurung, Naresh Pandeya, K. Deepak Singh 2020-12-30 2020-12-30 18 1 28 37 10.3126/on.v18i1.34239 Effect of Bamboo Substrate on Growth and Production of Carp and Small Indigenous Fish https://www.nepjol.info/index.php/ON/article/view/34240 <p>A field trial was conducted to examine effects of substrates on yield of carp and SIS at Sukranagar Village, Chitwan district for 210 days in farmer’s pond. The experiment was designed with four treatments: T<sub>1 </sub>(carp only), T<sub>2 </sub>(carp+SIS), T<sub>3 </sub>(carp+substrate) and T<sub>4 </sub>(carp+SIS+substrate) with four replicates. Ponds were stocked with fingerlings of six carp species at a rate of 20,000 fish/ha<em> and two Small indigenous fish species at a rate</em> of 50,000 fish/ha in 1:1 ratio. Prior to stocking of fish, split bamboo mats were fixed in substrate ponds covering 2% of pond surface area to enhance periphyton growth. Carp were fed with dough of rice bran and mustard oil cake (1:1) at the rate of 3% BW daily while Grass carp was fed with grass and banana leaves at 50% BW. Growth and yield of Rohu and Common carp, combined net fish yield and gross margin were found higher (p&lt;0.05) in carp ponds with substrate.</p> Rajan Poudel Sunila Rai Dilip K Jha Ram Bhajan Mandal Copyright (c) 2021 Rajan Poudel, Sunila Rai, Dilip K Jha, Ram Bhajan Mandal 2020-12-30 2020-12-30 18 1 38 48 10.3126/on.v18i1.34240