Madhav Shrestha - Academia.edu (original) (raw)

Papers by Madhav Shrestha

<title>Abstract</title> Pokhara valley is situated at the southwestern part ... more <title>Abstract</title> Pokhara valley is situated at the southwestern part of Kaski district in west Nepal. Although the valley is comprised of eight large and small lakes, cage culture is predominant in Begnas, Phewa and Rupa Lakes. A vulnerable fisher community known as <italic>pode</italic> or <italic>jalari</italic> living around the lakes of Pokhara Valley is among several ethnic groups whose livelihood is entirely dependent on fishing in these water bodies. A livelihood support programme for rehabilitation through creation of employment and income generation for this deprived community through subsistence cage aquaculture was initiated in 1972 in the lakes of the valley. Since then cage aquaculture has grown at a steady rate and at present 21,650 m3 of cages exist in these water bodies which produced an estimated 88.4 t of fish in 2004 to support the livelihoods of the 109 fisher families. Floating cages using four bamboo poles in a square as a float are popular in the fishers group. Mainly two species of carp are popular for culture in cages: bighead carp (<italic>Aristichthys nobilis</italic>) and silver carp (<italic>Hypophthalmichthys molitrix</italic>). Occasionally, other species are also stocked with bighead and silver carp such as rohu (<italic>Labeo rohita</italic>) as a biological cleaning agent to reduce fouling of the cage. The grass carp (<italic>Ctenopharyngodon idella</italic>) is also cultured in Lake Phewa on a small scale and is fed with grass. Average production of cages in Begnas, Phewa and Rupa Lakes is 3, 4.2 and 3.2 kg m-3 year-1, respectively.

CABI Compendium, Jan 7, 2022

This datasheet on Mixed-sex tilapia culture model for sub-tropical Nepal covers Identity, Overvie... more This datasheet on Mixed-sex tilapia culture model for sub-tropical Nepal covers Identity, Overview, Case Study, Environmental Requirements, Growout Systems, Related Content, Further Information.

Aquacultural Engineering, 1994

... Increasing attached microorganism biomass as a management strategy for Nile tilapia (Oreochro... more ... Increasing attached microorganism biomass as a management strategy for Nile tilapia (Oreochromis niloticus) production. ... Experiment 1 evaluated the effects of submerging plastic baffles in tanks on the production of attached microorganisms and Nile tilapia. ...

Aquacultural Engineering, Sep 1, 2001

An experiment was as conducted to evaluate the amount of wastes discharged from fish ponds during... more An experiment was as conducted to evaluate the amount of wastes discharged from fish ponds during harvest and to assess pond draining schemes and harvest techniques that may reduce waste loading in effluent water. Nile tilapia (Oreochromis niloticus) were cultured for 113-119 days in twelve 200 m 2 ponds with fertilization and supplementary pelleted feed. There were four treatments with three replicates each: (A) ponds were treated with teaseed cake at a rate of 10 ppm to partially anaesthetize tilapia 1.5 h prior to harvest by three seinings without draining ponds; (B) ponds were limed at a rate of 75 ppm calcium hydroxide 24 h prior to harvest and drained rained by sequential complete draining, and then tilapia were collected from a harvesting pit; (C) ponds were drained by sequential complete draining and tilapia were collected from a harvesting pit; and (D) ponds were drawn from 100 to 50 cm and tilapia were harvested by two seinings, followed by complete draining and collection of the remaining tilapia from a harvesting pit. Treatment D is the common practice in Thailand. The harvest efficiency was 97% in treatment A. Comparing the harvest efficiency for the he first two seinings, there were no significant differences between treatments A and D. Liming in treatment B resulted in significantly higher concentrations of 5 day ay biochemical oxygen demand, total settable matter, total solids and total phosphorus (TP) in the water discharged from the last 25 cm depth than those at both 100-50 and 50-25 cm depths, while there were no significant differences in effluent quality parameters among different depths in both treatments C and D. Concentrations of Management to Minimize the Environmental Impacts of Pond Effluent: Harvest Draining Techniques and Effluent Quality

Aquaculture, Jun 1, 1996

Two experiments were conducted to determine effective P fertilization strategy in fish ponds in r... more Two experiments were conducted to determine effective P fertilization strategy in fish ponds in relation to sediment P saturation level. Experiment 1 was conducted in cement tanks with five levels of P saturation in the sediments (5, 24, 44, 60 and 79%) and with three P fertilization rates (0.2, 0.1 and 0.05 g m−3 day−1, N:P ratios of 2:1, 4:1 and 8:1, respectively). Nile tilapia (Oreochromis niloticus) were cultured in the tanks for 57 days. Results showed that the mean concentration of soluble reactive phosphorus (SRP) in the water column increased with increasing sediment P saturation and P fertilization rate. The maximum net fish yield (NFY), 4.2 ± 0.3 g m−3 day−1, was obtained at an SRP concentration of 0.3 mg 1−1; higher concentrations did not increase fish yield. These levels of SRP and NFY were attainable with P fertilization rates of 0.2 g m−3 day−1, 0.1 g m−3 day−1 and 0.05 g m−3 day−1 and N:P ratios of 2:1, 4:1 and 8:1 in ponds where the level of sediment P saturation was below 10%, above 45% and above 60%, respectively. Experiment 2 was conducted in earthen ponds to test and verify the P fertilization rate based on the cement tank results. Three new and three old ponds with 8 ± 1.7% and 88 ± 7.3% sediment P saturated in the top 5 cm of mud were fertilized at a rate of 0.2 g m−3 day−1 and 0.05 g m−3 day−1 and N:P ratio of 2:1 and 8:1, respectively. Nile tilapia were cultured at a density of two fish m−3 for 85 days. The mean NFY obtained in new and old ponds were 1.73 ± 0.08 g m−3 day−1 and 2.24 ± 0.32 g m−3 day−1, respectively, which were not significantly different (P > 0.05). We conclude that P fertilization rate should be based on P saturation level in mud to overcome the problem of under or over supply of P in fish ponds.

Journal of the Institute of Agriculture and Animal Science, Jan 4, 2007

A preliminary study on nursing, growth, and survival of fresh water prawn ( Macrobrachium rosenbe... more A preliminary study on nursing, growth, and survival of fresh water prawn ( Macrobrachium rosenbergii ) was carried out at the Institute of Agriculture and Animal Science (IAAS) and also in the farmer's pond at Kathar, Chitwan during March 2002 to April 2003. About 6% of first stage nursing of post larvae survived for 19 days in hapa installed in green water cement tanks compared to 60% for juvenile nursing in open cement tanks. Prawn stocked at 2/m 2 at IAAS cement tank grew from 1 to 17.7±2.6 g in 271 days with a range of 3 to 43 g sizes and the survival rate was 35±15% with a range of 17 to 65%. Similarly, prawn grew from 1 g to 42.7±13.6 g in 234 days with a range of 6 to 89 g in farmers' earthen ponds at Kathar. Survival rate in farmers' pond at harvest ranged from 20 to 28%. Low survival rate was due to prawn mortality during first week of January when water temperature dropped below 15 o C as pond water level was less than 0.5 m. Prawns at IAAS were observed at fully maturity with several berried females during March 2003. Growth of prawn was higher in farmer's earthen pond than in cement tank at IAAS in polyculture with carps/tilapia. Results clearly indicate that nursing techniques of post larvae need to be improved to increase its survival rate. Harvest size of prawn indicates its possibility to culture in subtropical conditions of Nepal. However, as low temperature hinders growth and survival of fresh water prawn, culture cycle and season have to be standardized to avoid winter cold temperature. Keywords: Fresh water prawn, post larvae, juvenile, polyculture J. Inst. Agric. Anim. Sci. 25:75-78 2004

Aquaculture Research, Nov 22, 2012

ABSTRACT Cage-pond integration system is a new model for enhancing productivity of pond aquacultu... more ABSTRACT Cage-pond integration system is a new model for enhancing productivity of pond aquaculture system. A field trial was conducted using African catfish (Clarias gariepinus) and Nile tilapia (Oreochromis niloticus) in cages and carps in earthen ponds. There were four treatments replicated five times: (1) carps in ponds without cage, (2) tilapia at 30 fish m−3 in cage and carps in open pond, (3) catfish at 100 fish m−3 in cage and carps in open pond, (4) tilapia and catfish at 30 and 100 fish m−3, respectively, in separate cages and carps in open pond. The carps were stocked at 1 fish m−2. The cage occupied about 3% of the pond area. The caged tilapia and catfish were fed and the control ponds were fertilized. Results showed that the combined extrapolated net yield was significantly higher (P < 0.05) in the catfish, tilapia and carps integration system (9.4 ± 1.6 t ha−1 year−1) than in the carp polyculture (3.3 ± 0.7 t ha−1 year−1). The net return from the tilapia and carps (6860 US$ ha−1 year−1) and catfish, tilapia and carps integration systems (6668 US$ ha−1 year−1) was significantly higher than in the carp polyculture (1709 US$ ha−1 year−1) (P < 0.05). This experiment demonstrated that the cage-pond integration of African catfish and Nile tilapia with carps is the best technology to increase production; whereas integration of tilapia and carp for profitability.

Aquatic Ecosystem Health & Management, 2023

Nepal is endowed with vast water resources in form of glaciers, lakes, streams and rivers. All th... more Nepal is endowed with vast water resources in form of glaciers, lakes, streams and rivers. All the rivers in Nepal are connected to the Ganges River system of India. The major rivers are reliable sources of water and provide habitats for aquatic animals, opportunities for hydropower, and irrigation development in downstream regions. The major rivers of Nepal include the Koshi, Gandaki (Narayani), Karnali, and Mahakali which all drain from north to south. These rivers support abundant wildlife species as well as a number of fishes, amphibians and reptiles. Most relevant to this paper is the Ganges River Dolphin (Platanista gangetica gangetica Roxburgh, 1801). The Ganges River Dolphin preys on fish, mollusks and other aquatic animals. Being a migratory species, the dolphins move from larger rivers to their tributaries, seasonally. This paper is intended to review work on the status of Ganges River Dolphin in Nepalese rivers based on secondary data obtained from different published surveys targeting the dolphin populations. The records show the Karnali River has the largest population, followed by the Koshi and Narayani rivers, with no record of dolphins occupying the Mahakali River in recent years. Recent surveys estimate about 100 dolphins living in Nepal, with 80 estimated in the Karnali River. Different anthropogenic activities including construction work, intensive fishing, pollution and the lack of conservation planning for dolphins have resulted in a decline in number from historic levels. The presence of this aquatic mammal is considered as an indicator of the overall health of the river system. The COVID-19 pandemic and lock down might have caused increased dolphin sightings. Additionally, high pre-monsoon precipitation in recent years have caused higher water levels in smaller rivers, possibly causing the dolphins to return earlier than usual to the major river systems. They were recorded to be present in the Mohana and other small tributaries of the Karnali River as early as first week of June.

Fisheries and aquaculture policy for education, research and extension is derivatives of the main... more Fisheries and aquaculture policy for education, research and extension is derivatives of the main national agriculture policy. Fisheries and aquaculture is a dynamic sub-sector of agriculture sector having high growth potential but with low organizational stature in Nepal. The modern aquaculture along with fisheries practices contributes nearly 1% of Gross Domestic Production (GDP) and 2.68% of Agriculture Gross Domestic Production (AGDP). This positive achievement of the sub-sector, contrary to others whose contribution in GDP has declined over the years, suggests its popularity among farmers. Similarly, Government of Nepal has recognized the importance of fisheries and aquaculture for nutritional supply and poverty reduction. The primary objective of the national fisheries and aquaculture policy is to contribute to economic growth and poverty reduction through inclusive, equity-based and Ecosystem Approach of Aquaculture (EAA). Specific laws and legislation on aquaculture development have to be formulated or enforced for building capacity and facilitating entrepreneurship, especially in the context of the World Trade Organization (WTO). Besides, Best Management Practices (BMPs) also need to be identified and adopted to achieve sustainable growth of the sub-sector.

International Journal of Fisheries and Aquatic Studies

Conventional multispecies polyculture with compatible native species intercrop augments optimum u... more Conventional multispecies polyculture with compatible native species intercrop augments optimum utilization of the ecological niches in the pond ecosystem, diversity conservation, food value, and poverty alleviation potential through the direct involvement of rural people. Given the conservational value and the aquaculture potential of several indigenous species, Gardi Bangana dero and Sahar Tor putitora have been identified as important food fish. Rohu Labeo rohita and Naini Cirrhinus mrigala are two other native fishes that fetch a very high market price and are of high cultural value. A polyculture experiment was carried out on the Rohu, Naini, Gardi, and Sahar with the objectives to evaluate the optimum stocking density in terms of average body weight, specific growth rate, and total fish production of these fishes for nine months. Results showed that the final body weight of Rohu, Naini, Gardi were high in respective major polyculture systems, but Sahar was high in Naini major polyculture system. Also, net fish yield of Rohu was observed significantly higher in Rohu major polyculture system than in Naini major and Gardi major polyculture systems but not with control polyculture systems. Whereas, parameters of Naini, Gardi and Sahar observed similar in all polyculture systems. Apparent Feed Conversion Ratio was found higher in Gardi major polyculture system than others. In case of survival, all fish species had high survival rate in Naini major polyculture system. Thus, the Naini major polyculture system is concluded to be the optimum combination for these particular species.

Asian Fisheries Science

An experiment was conducted in outdoor cement ponds for three months to evaluate the growth and p... more An experiment was conducted in outdoor cement ponds for three months to evaluate the growth and production of grass carp (Cte11oplwryngodon idella) and other polycultured species fed with napier grass (Pennisetu.m pul'pttreum). Chopped fresh napier grass was fed every day at ad libitw11 to grass carp stocked in three combinations in triplicates: (1) monoculture of grass carp; (2) polyculture of grass carp, silver carp (llypophthalmichth_ys molitrix) and bighead carp (Aristichthys nobilis); and (3) polyculture of grass carp, silver carp, bighead carp and common carp (Cyprinus carpio). Mean net fish yield (NFY) of grass carp obtained was: 1.22, 1.25±0.05 and 1.04±0.01 g•m• 2 •day-1 with total NFY of 1.22, 1.62±0.04 and 1.44±0.01 g•m• 2 •day-1 in treatments 1, 2 and 3, respectively. Mean food conversion ratio (FCR) of fresh napier grass to grass carp production was 17.3, 17.9±0.6 and 21.9±0.4, whereas, to total fish production, this was 17.3, 13.5±0.3 and 15.0±0.3 in treatment.'-! 1, 2 and 3, respectively. Results clearly indicated that waste of grass carp cultivation fed on grass can irnpport the production of other fish species and that, as shown by NFY and FCR, grass carp and common carp compete on grasses. Water quality was less a problem in polyculture than that in monoculture despite the higher stocking density in polyculture. Mass mortality of grass carps occurred in two replications of monoculture treatment due to the low level of dissolved oxygen in the ninth week of the experiment.

Asian Fisheries Science

Mixed-sex Nile tilapia (Oreochromis niloticus) and common carp (Cyprinus carpio) were cultured in... more Mixed-sex Nile tilapia (Oreochromis niloticus) and common carp (Cyprinus carpio) were cultured in four cement ponds of 72 m2 at 1:1 ratio with a stocking density of 1 fish· m·2 during summer in subtropical Nepal. Fish were fed with locally collected duckweed (Spirodela sp.) during 108 days of experimental period. Nile tilapia grew from 39.6±3.7 g at stocking to 145±5.2 g at harvesting with a survival rate of 90±4 %. Common carp grew from an initial 2.8±0.G g to final 63.2±2.4 g with 97±1 % survival rate. The extrapolated annual yield of stocked fish ranger.! from 2.3 - 2.9 t•ha·1 with a mean of 2.5 ±0.1 t·ha·1. Tilapia offsprings produced during the experimental period was 1690:±261 fish per pond with an average size of 7.2±1.6 g. Weight of tilapia recruits obtained was two times more than that of the net yield of originally stocked fish. The common carp did not control tilapia recruitments.

Journal of Agriculture and Forestry University

Algal red bloom in carp ponds has been a serious concern to farmers due its scum covering the ent... more Algal red bloom in carp ponds has been a serious concern to farmers due its scum covering the entire pond surface area during the day and disappearing in the evening. Thus it is important to examine the effects of sunlight on dynamics of red bloom algae in ponds. An experiment was done with the use of three treatments, i) non-red bloom pond with sunlight, ii), red bloom pond with sunlight, and iii) red bloom pond without sunlight; each treatment was replicated thrice. Density of Euglenophyceae was assessed from two different water depths (10 cm and 50 cm) at three different times: morning, afternoon, and evening. Results showed that Euglena sanguinea Ehrenberg, 1832 was dominant among euglenophytes and it showed vertical and temporal migration with sunlight intensity. Density of E. sanguinea was significantly higher (p<0.05) at 10 cm and lower (p<0.05) at 50 cm in the afternoon. Preventing sunlight to the red bloom pond decreased density of Euglenophyceae and E. sanguinea by 6...

Content in this publication is licensed under a Creative Commons Attribution-NonCommercial-NoDeri... more Content in this publication is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way.

Our Nature, 2015

17 α-Methyltestosterone (MT) is a commonly used synthetic androgen for the all male tilapia fry p... more 17 α-Methyltestosterone (MT) is a commonly used synthetic androgen for the all male tilapia fry production. The probable residual effect of MT on human health and environment has been a concern. Two trials for two seasons were conducted to evaluate the effectiveness of carp testis (CT), as a source of natural androgen, on sex reversal of Nile tilapia (Oreochromis niloticus) and compare it with MT at Department of Aquaculture, Agriculture and Forestry University, Nepal,using completely randomised block deign (RCBD). Altogether 8 treatments with 4 for methyltestosterone (40 mg MT kg-1 of diet) and 4 for 75% rohu (Labeo rohita) testis. Both source of androgen were fed for 15, 18, 21 or 24 days. Treatments were replicated thrice. The result of methyltestosterone feeding for 24 days showed significantly (p<0.05) higher percentage of male (98.5±1.5) than 15 days (87.1±3.5) but was statistically similar with 18 (91.8±2.6) and 21(94.3±3.0) days feeding. Similarly percentage of male obtai...

Journal of Agriculture and Forestry University

Red blooms caused by Euglena sanguinea (Ehrenberg, 1832) might cause severe depletion of dissolve... more Red blooms caused by Euglena sanguinea (Ehrenberg, 1832) might cause severe depletion of dissolved oxygen significantly in the pond. An experiment was conducted to assess the effects of measures for controlling E. sanguinea on water quality, growth and yield of carp polyculture. The experiment included four treatments: without mitigation measure (T1), skimming using net skimmer (T2), fertilization with urea and diammonium phosphate (T3) and liming using agriculture lime (T4) with three replications. The experiment was carried out for 120 days. The results showed that abundance of E. sanguinea was significantly lower (p < 0.05) in urea and diammonium phosphate treated ponds (270 ± 10 cells L-1) than control ponds (1650 ± 90 cells L-1). Water quality parameter such as nitrite, total nitrogen and total phosphorus were significantly (p < 0.05) higher in control ponds (T1) than in treatment ponds. The net fish yield of rohu was significantly higher (0.19 ± 0.0 t ha-1) in T3 ponds t...

Asian Fisheries Science, Dec 15, 2014

International Journal of Fisheries and Aquatic Studies

CABI Compendium, Jan 7, 2022

Aquacultural Engineering, 1994

Aquacultural Engineering, Sep 1, 2001

Aquaculture, Jun 1, 1996

Journal of the Institute of Agriculture and Animal Science, Jan 4, 2007

Aquaculture Research, Nov 22, 2012

Aquatic Ecosystem Health & Management, 2023

International Journal of Fisheries and Aquatic Studies

Asian Fisheries Science

Journal of Agriculture and Forestry University

Our Nature, 2015

Journal of Agriculture and Forestry University

Asian Fisheries Science, Dec 15, 2014

International Journal of Fisheries and Aquatic Studies