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2. Four ways blue foods can help achieve food system ambitions across nations

Author

Crona, B.I., Wassénius, E., Jonell, M., Koehn, J.Z., Short, R., Tigchelaar, M., Daw, T.M., Golden, C.D., Gephart, J.A., Allison, E.H., Bush, S.R., Cao, L., Cheung, W.W.L., DeClerck, F., Fanzo, J., Gelcich, S., Kishore, A., Halpern, B.S., Hicks, C.C., Leape, J.P., Little, D.C., Micheli, F., Naylor, R.L., Phillips, M., Selig, E.R., Springmann, M., Sumaila, U.R., Troell, M., Thilsted, S.H., Wabnitz, C.C.C., Crona, B.I., Wassénius, E., Jonell, M., Koehn, J.Z., Short, R., Tigchelaar, M., Daw, T.M., Golden, C.D., Gephart, J.A., Allison, E.H., Bush, S.R., Cao, L., Cheung, W.W.L., DeClerck, F., Fanzo, J., Gelcich, S., Kishore, A., Halpern, B.S., Hicks, C.C., Leape, J.P., Little, D.C., Micheli, F., Naylor, R.L., Phillips, M., Selig, E.R., Springmann, M., Sumaila, U.R., Troell, M., Thilsted, S.H., and Wabnitz, C.C.C.

Abstract

Blue foods, sourced in aquatic environments, are important for the economies, livelihoods, nutritional security and cultures of people in many nations. They are often nutrient rich1, generate lower emissions and impacts on land and water than many terrestrial meats2, and contribute to the health3, wellbeing and livelihoods of many rural communities4. The Blue Food Assessment recently evaluated nutritional, environmental, economic and justice dimensions of blue foods globally. Here we integrate these findings and translate them into four policy objectives to help realize the contributions that blue foods can make to national food systems around the world: ensuring supplies of critical nutrients, providing healthy alternatives to terrestrial meat, reducing dietary environmental footprints and safeguarding blue food contributions to nutrition, just economies and livelihoods under a changing climate. To account for how context-specific environmental, socio-economic and cultural aspects affect this contribution, we assess the relevance of each policy objective for individual countries, and examine associated co-benefits and trade-offs at national and international scales. We find that in many African and South American nations, facilitating consumption of culturally relevant blue food, especially among nutritionally vulnerable population segments, could address vitamin B12 and omega-3 deficiencies. Meanwhile, in many global North nations, cardiovascular disease rates and large greenhouse gas footprints from ruminant meat intake could be lowered through moderate consumption of seafood with low environmental impact. The analytical framework we provide also identifies countries with high future risk, for whom climate adaptation of blue food systems will be particularly important. Overall the framework helps decision makers to assess the blue food policy objectives most relevant to their geographies, and to compare and contrast the benefits and trade-offs associated with pur

Published
2023

4. Operationalising dietary acceptability: A systematic review on how acceptability is applied in dietary optimisation models.

Author

Baungaard, C., Martins, M.A., Horgan, G.W., Little, D.C., Hillier, J., and de Roos, B.

Abstract

The current environmental, climate and health challenges require critical transitions to diets and food production systems that are more sustainable, in turn providing diets that are adequate nutrition, affordable and environmentally friendly. Recent studies have identified cultural acceptability as an important dimension in sustainable diets(1). Mathematical optimization models have been developed to deal with the complexities of all the dimensions, yet diet acceptability has had limited successful integration into these models(2). This systematic review explored two research questions in the context of dietary optimisation studies; how is acceptability defined and operationalised?; how does including acceptability impact dietary optimisation solutions? A hybrid search strategy was implemented. The first used the PRISMA guidelines to conduct a systematic search on two electronic databases (PubMed, Embase) for articles published between January 2013 and April 2024. Search terms were developed through preliminary readings and included: diet OR diets OR dietary AND modelling OR modeling OR optimisation OR optimization OR optimize OR optimize OR linear programming AND acceptabl*. Articles in English optimising acceptable diets for adults (18+) were included. The second used the snowball method for identifying relevant articles from previous searches(3). Backward snowballing was conducted by identifying references from the initial set and forward snowballing was conducted through Web of Science in June 2023. Fifty-one studies fulfilled the inclusion criteria. European countries had the largest representation (n = 41; 20 from France, 7 from The Netherlands); 43 studies took a population-based modelling approach, 7 on individual-based modelling and 1 study used both approaches. The review identified 12 modelling approaches, where linear programming was most frequently used (n = 26), followed by non-linear programming (n = 7) and quadratic (n = 6). The majority of studies that optimised for acceptability used the minimal deviation from observed diet as the objective function (n = 32). Baseline dietary data for observed diets were primarily from National surveys (n = 36), followed by local surveys (n = 5), however, 25 studies used data that was 8 – 16 years older than the publication date. Majority of studies included at least one acceptability constraint (n = 45), ranging from setting boundaries on certain foods (n = 34), removal of certain foods/food groups (n = 12), limiting deviation (n = 15). The full analysis of the studies is ongoing; however the current results highlight the varying methods used to operationalising 'acceptable' diets in diet optimisation literature. A conceptual framework for integrating acceptability into diet optimisation studies is currently under development, aiming to highlight the various ways in which 'acceptability' is operationalised through the modelling process from data inputs, models chosen to validation of the solutions. It is anticipated that this work will highlight new opportunities for further modelling for acceptable diets. [ABSTRACT FROM AUTHOR]

Published
2024
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8. Harnessing the diversity of small-scale actors is key to the future of aquatic food systems

Author

Short, R.E., Gelcich, S., Little, D.C., Micheli, F., Allison, E.H., Basurto, X., Belton, B., Brugere, C., Bush, S.R., Cao, L., Crona, B., Cohen, P.J., Defeo, O., Edwards, P., Ferguson, C.E., Franz, N., Golden, C.D., Halpern, B.S., Hazen, L., Hicks, C., Johnson, D., Kaminski, A.M., Mangubhai, S., Naylor, R.L., Reantaso, M., Sumaila, U.R., Thilsted, S.H., Tigchelaar, M., Wabnitz, C.C.C., Zhang, W., Short, R.E., Gelcich, S., Little, D.C., Micheli, F., Allison, E.H., Basurto, X., Belton, B., Brugere, C., Bush, S.R., Cao, L., Crona, B., Cohen, P.J., Defeo, O., Edwards, P., Ferguson, C.E., Franz, N., Golden, C.D., Halpern, B.S., Hazen, L., Hicks, C., Johnson, D., Kaminski, A.M., Mangubhai, S., Naylor, R.L., Reantaso, M., Sumaila, U.R., Thilsted, S.H., Tigchelaar, M., Wabnitz, C.C.C., and Zhang, W.

Abstract

Small-scale fisheries and aquaculture (SSFA) provide livelihoods for over 100 million people and sustenance for ~1 billion people, particularly in the Global South. Aquatic foods are distributed through diverse supply chains, with the potential to be highly adaptable to stresses and shocks, but face a growing range of threats and adaptive challenges. Contemporary governance assumes homogeneity in SSFA despite the diverse nature of this sector. Here we use SSFA actor profiles to capture the key dimensions and dynamism of SSFA diversity, reviewing contemporary threats and exploring opportunities for the SSFA sector. The heuristic framework can inform adaptive governance actions supporting the diversity and vital roles of SSFA in food systems, and in the health and livelihoods of nutritionally vulnerable people—supporting their viability through appropriate policies whilst fostering equitable and sustainable food systems.

Published
2021

9. Scenarios for Global Aquaculture and Its Role in Human Nutrition

Author

Gephart, J.A., Golden, C.D., Asche, F., Belton, B., Brugere, C., Froehlich, H.E., Fry, J.P., Halpern, B.S., Hicks, C.C., Jones, R.C., Klinger, D.H., Little, D.C., McCauley, D.J., Thilsted, S.H., Troell, M., Allison, E.H., Gephart, J.A., Golden, C.D., Asche, F., Belton, B., Brugere, C., Froehlich, H.E., Fry, J.P., Halpern, B.S., Hicks, C.C., Jones, R.C., Klinger, D.H., Little, D.C., McCauley, D.J., Thilsted, S.H., Troell, M., and Allison, E.H.

Abstract

Global demand for freshwater and marine foods (i.e., seafood) is rising and an increasing proportion is farmed. Aquaculture encompasses a range of species and cultivation methods, resulting in diverse social, economic, nutritional, and environmental outcomes. As a result, how aquaculture develops will influence human wellbeing and environmental health outcomes. Recognition of this has spurred a push for nutrition-sensitive aquaculture, which aims to benefit public health through the production of diverse, nutrient-rich seafood and enabling equitable access. This article explores plausible aquaculture futures and their role in nutrition security using a qualitative scenario approach. Two dimensions of economic development–the degree of globalization and the predominant economic development philosophy–bound four scenarios representing systems that are either localized or globalized, and orientated toward maximizing sectoral economic growth or to meeting environmental and equity dimensions of sustainability. The potential contribution of aquaculture in improving nutrition security is then evaluated within each scenario. While aquaculture could be “nutrition-sensitive” under any of the scenarios, its contribution to addressing health inequities is more likely in the economic and political context of a more globally harmonized trade environment and where economic policies are oriented toward social equity and environmental sustainability.

Published
2021

10. Emerging COVID-19 impacts, responses, and lessons for building resilience in the seafood system

Author

Love, D.C., Allison, E.H., Asche, F., Belton, B., Cottrell, R.S., Froehlich, H.E., Gephart, J.A., Hicks, C.C., Little, D.C., Nussbaumer, E.M., Pinto da Silva, P., Poulain, F., Rubio, A., Stoll, J.S., Tlusty, M.F., Thorne-Lyman, A.L., Troell, M., Zhang, W., Love, D.C., Allison, E.H., Asche, F., Belton, B., Cottrell, R.S., Froehlich, H.E., Gephart, J.A., Hicks, C.C., Little, D.C., Nussbaumer, E.M., Pinto da Silva, P., Poulain, F., Rubio, A., Stoll, J.S., Tlusty, M.F., Thorne-Lyman, A.L., Troell, M., and Zhang, W.

Abstract

The COVID-19 pandemic and subsequent lockdowns are creating health and economic crises that threaten food and nutrition security. The seafood sector provides important sources of nutrition and employment, especially in low-income countries, and is highly globalized allowing shocks to propagate. We studied COVID-19-related disruptions, impacts, and responses to the seafood sector from January through May 2020, using a food system resilience ‘action cycle’ framework as a guide. We find that some supply chains, market segments, companies, small-scale actors and civil society have shown initial signs of greater resilience than others. COVID-19 has also highlighted the vulnerability of certain groups working in- or dependent on the seafood sector. We discuss early coping and adaptive responses combined with lessons from past shocks that could be considered when building resilience in the sector. We end with strategic research needs to support learning from COVID-19 impacts and responses.

Published
2021

13. Sustaining ethical trade in farmed aquatic products between Asia and the EU

Author

Little, D.C., primary, Murray, F.J., additional, Telfer, T.C., additional, Young, J.A., additional, Ross, L.G., additional, Hill, B., additional, Dalsgard, A., additional, Van den Brink, P., additional, Guinée, J., additional, Kleijn, R., additional, Mungkung, R., additional, Yi, Y., additional, Min, J., additional, Liping, L., additional, Huanan, L., additional, Yuan, L., additional, Derun, Y., additional, Phuong, N.T., additional, Hai, T.N., additional, Liem, P.T., additional, Ut, V.N, additional, Tung, V.T., additional, Viet, T.V., additional, Satapornvanit, K., additional, Pongthanapanich, T., additional, Wahab, M.A., additional, Nowsad Alam, A.K.M., additional, Haque, M.M., additional, Salam, M.A., additional, Corsin, F., additional, Pemsl, D., additional, Allison, E., additional, Beveridge, M.C.M., additional, Karunasagar, I., additional, Subasinghe, R., additional, Kaiser, M., additional, Sveinson Haugen, A., additional, and Ponte, S., additional

Published
2009
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16. Emerging trends in aquaculture value chain research

Author

Bush, S.R., Belton, Ben, Little, D.C., Islam, Saidul, Bush, S.R., Belton, Ben, Little, D.C., and Islam, Saidul

Abstract

This paper introduces a special issue of Aquaculture that brings together the largest collection of research on aquaculture value chains compiled to date, comprising 19 individual papers and this introductory review. The introduction identifies five themes emerging from research on aquaculture value chains in the special issue, namely: multi-polarity, diversity and scale, dynamics of transformation, performance and equity, and technical and institutional innovation. Contrary to much research to date, the papers addressing these themes show how the expansion of aquaculture has resulted highly diverse configurations of production for consumption in the global South. Collectively, the papers highlight the need for greater attention to neglected value chain segments and categories of actor, modes of production, regulation, and innovation, and patterns of access to benefits. The papers synthesized also affirm the need for more rigorous and diverse future value chain research to illuminate the aquaculture sector's ongoing development, and contribute to the sustainable expansion as an increasingly important component of the global food system.

Published
2019

19. Let Them Eat Carp: Fish Farms Are Helping to Fight Hunger

Author

Belton, Ben, Bush, S.R., and Little, D.C.

Subjects
Milieubeleid, WIMEK, WASS, Environmental Policy
Abstract

The importance of global trade in farmed seafood has been vastly overstated. The vast majority of farmed fish is consumed in the same developing countries where it is produced and is widely accessible to poorer consumers in these markets. Most of it comes from a dynamic new class of small- and medium-scale commercial farms,the existence of which is rarely recognized.

Published
2018

23. Introducing: Aquaculture Reports

Author

van Dam, A.A., Valenti, W.C., Zhang, W., Austin, B., Benzie, J.A.H., Costa-Pierce, B.A., Farrell, A.P., Gatlin, D.M., Hulata, G., and Little, D.C.

Subjects
lcsh:SH1-691, Animal Science and Zoology, Aquatic Science, lcsh:Aquaculture. Fisheries. Angling
Published
2015

24. A comparison of Asian aquaculture products using statistically supported LCA

Author

Henriksson, P.J.G., Rico, A., Zhang, W., Al-Nahid, A., Newton, R., Phan, L.T., Zhang, Z., Jaithiang, J., Dao, H.M., Phu, T.M., Little, D.C., Murray, F.J., Satapornvanit, K., Liu, L., Liu, Q., Haque, M.M., Kruijssen, F., de Snoo, G.R., Heijungs, R., van Bodegom, P., and Econometrics and Operations Research

Subjects
SDG 14 - Life Below Water
Abstract

We investigated aquaculture production of Asian tiger shrimp, whiteleg shrimp, giant river prawn, tilapia, and pangasius catfish in Bangladesh, China, Thailand, and Vietnam by using life cycle assessments (LCAs), with the purpose of evaluating the comparative eco-efficiency of producing different aquatic food products. Our starting hypothesis was that different production systems are associated with significantly different environmental impacts, as the production of these aquatic species differs in intensity and management practices. In order to test this hypothesis, we estimated each system's global warming, eutrophication, and freshwater ecotoxicity impacts. The contribution to these impacts and the overall dispersions relative to results were propagated by Monte Carlo simulations and dependent sampling. Paired testing showed significant (p < 0.05) differences between the median impacts of most production systems in the intraspecies comparisons, even after a Bonferroni correction. For the full distributions instead of only the median, only for Asian tiger shrimp did more than 95% of the propagated Monte Carlo results favor certain farming systems. The major environmental hot-spots driving the differences in environmental performance among systems were fishmeal from mixed fisheries for global warming, pond runoff and sediment discards for eutrophication, and agricultural pesticides, metals, benzalkonium chloride, and other chlorine-releasing compounds for freshwater ecotoxicity. The Asian aquaculture industry should therefore strive toward farming systems relying upon pelleted species-specific feeds, where the fishmeal inclusion is limited and sourced sustainably. Also, excessive nutrients should be recycled in integrated organic agriculture together with efficient aeration solutions powered by renewable energy sources.

Published
2015
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26. Commercial production and marketing of Nile tilapia (Oreochromis niloticus) fry in Chonburi and Chachoengsao provinces, Thailand

Author

Little, D.C., Sikawa, D., and Juntana, J.

Subjects
Fry, Marketing, Chachoengsao, Tilapia culture, Fry, Marketing, Chonburi, Chachoengsao, Thailand, Oreochromis niloticus, jel:Q00, Tilapia culture, Oreochromis niloticus, Chonburi, Aquaculture, Thailand
Abstract

Nile tilapia (Oreochromis niloticus) fry production and marketing in the provinces of Chonburi and Chachoengsao, Thailand are discussed, covering historical background, production methodology, transfer of technology to other region, and future trends.

Published
1994

27. Livelihood impacts of ponds in Asia-opportunities and constraints

Author

Little, D.C., Karim, M., Turongrouang, Danai, Morales, E.J., Murray, F.J., Barman, B.K., Hague, M.M., Kundu, N., Belton, B., Faruque, A.S.G., Azim, M.E., Islam, F.U., Pollock, L., Verdegem, M.C.J., Young, J.A., Leschen, W., and Wahab, M.A.

Subjects
Livelihood, Aquaculture and Fisheries, Aquacultuur en Visserij, WIAS, Vulnerability, Multiple-use, Seasonality, Fishpond, PE&RC
Published
2007

28. EFFICIENCY OF THE AGROCHEMICAL INPUT USAGE IN THE PADDY FARMING SYSTEMS IN THE DRY ZONE OF SRI LANKA

Author

Udayanganie, A.D.D., Prasada, Dickwella Vidanage Pahan, Kodithuwakku, K.A.S.S., Weerahewa, Jeevika, and Little, D.C.

Subjects
Crop Production/Industries
Abstract

This paper assesses the technical efficiency of paddy production in one of the major irrigation schemes in Sri Lanka with special emphasis on the usage of agrochemical inputs and determinants of technical efficiency. The presence of technical inefficiency and its causality is investigated using a stochastic production frontier model. Data for the estimation was gathered from a farm household survey covering 225 households across five administrative units from 3 irrigation blocks for the cultivation season 2003/2004. The results of the production function show negative relationships between yield and the cost of pesticides indicating an over use of pesticides. The average technical efficiency was estimated to be 0.37. Among the determinants of inefficiency estimates considered, the importance of credit and extension services on improving efficiency of farmer stand out while the farmers come from neighbouring villages appear efficient than the farmers settled in the villages.

Published
2006
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29. The role of ponds in livelihoods

Author

Wahab, M.A., Little, D.C., Azim, M.E., and Verdegem, M.C.J.

Subjects
Aquaculture and Fisheries, Aquacultuur en Visserij, WIAS, Life Science
Published
2005

31. Effect of phosphorous supplementation in the formulated fish feed on carcass quality of Nile tilapia Oreochromis niloticus L

Author

Sarkar, M.R.U., Yakupitiyage, A., Lin, C.K., and Little, D.C.

Subjects
Carcass quality, Di-calcium phosphate, Fisheries, Bone phosphorus, virus diseases, Phosphorus, Aquaculture, human activities, Triple super phosphate
Abstract

A study was conducted to evaluate the effect of phosphorus supplementation in the formulated fish diet on carcass quality of Nile tilapia in net-cages suspended in fertilized earthen ponds. In the experiment 3% di-calcium phosphate (DCP), 3% triple supper phosphate (TSP) and 7% 16:20 inorganic fertilizer were added as phosphorous sources to three diets containing fish meal as main protein ingredient. Feeding tilapia in net-cages with these diets significantly (p

Published
2004

32. Risks of pesticide use in aquatic ecosystems adjacent to mixed vegetable and monocrop fruit growing areas in Thailand

Author

Satapornvanit, K., Baird, D.J., Little, D.C., Milwain, G.K., van den Brink, P.J., Beltman, W.H.J., Nogueira, A.J.A., Daam, M.A., Domingues, I., Kodithuwakku, S.S., Perera, M.W.P., Yakupitiyage, A., Sureshkumar, S.N., and Taylor, G.J.

Subjects
Aquatic Ecology and Water Quality Management, WIMEK, Alterra - Centre for Water and Climate, Life Science, Wageningen Environmental Research, Aquatische Ecologie en Waterkwaliteitsbeheer, Alterra - Centrum Water en Klimaat
Published
2004

35. Certify Sustainable Aquaculture?

Author

Bush, S.R., Belton, B., Hall, D., Vandergeest, P., Murray, F.J., Ponte, S., Oosterveer, P.J.M., Islam, M.S., Mol, A.P.J., Hatanaka, M., Kruijssen, F., Ha, T.T.T., Little, D.C., Kusumawati, R., Bush, S.R., Belton, B., Hall, D., Vandergeest, P., Murray, F.J., Ponte, S., Oosterveer, P.J.M., Islam, M.S., Mol, A.P.J., Hatanaka, M., Kruijssen, F., Ha, T.T.T., Little, D.C., and Kusumawati, R.

Abstract

Aquaculture, the farming of aquatic organisms, provides close to 50% of the world's supply of seafood, with a value of U.S. $125 billion. It makes up 13% of the world's animal-source protein (excluding eggs and dairy) and employs an estimated 24 million people (1). With capture (i.e., wild) fisheries production stagnating, aquaculture may help close the forecast global deficit in fish protein by 2020 (2). This so-called “blue revolution” requires addressing a range of environmental and social problems, including water pollution, degradation of ecosystems, and violation of labor standards.

Published
2013

36. Alternative phosphorus sources for formulated fish feed

Author

Sarkar, M.R.U., Yakupitiyage, A., Lin, C.K., and Little, D.C.

Subjects
Di-calcium phosphate, Fisheries, Duck-manure, virus diseases, Phosphorus, Aquaculture, Triple super phosphate
Abstract

An experiment was conducted to evaluate the possibility of using inorganic fertilizer triple super phosphate (TSP), inorganic fertilizer 16:20 (a 16:20 grade fertilizer contains 16 percent N and 20 percent P20 5), rice-bran and duck-manure as phosphorus sources in formulated fish feed for Nile tilapia ( Oreochromis niloticus). Experiment was conducted for a period of 2 months in net-cages suspended in fertilized earthen ponds and all male sex-reversed Nile tilapia (9.39- 10.37 g) were used in the experiment. Seven treatments including one non-feed treatment were used in this experiment. Treatment 1 (non-feed), treatment 2 (-P) where fish fed with phosphorus non-supplemented diet acted as control 1 and treatment 3, 4, 5, 6 and 7 where fish fed with 3% di-calcium phosphate (DCP), 3% triple supper phosphate (TSP), 7% 16:20 inorganic fertilizer, 30% rice-bran and 30% duck-manure supplemented diet, respectively. Results showed that the TSP and 16:20 grade inorganic fertilizer supplementation in diets as phosphorus sources were equivalent to DCP (Di-calcium phosphate) supplementation in terms of growth performance, feed utilization efficiency and final body composition of Nile tilapia. Ricebran and duck-manure were not found as good phosphorus sources.

Published
2002

37. Small-Scale farmer-managed aquaculture in engineered water systems: Critical design and management approaches. Project R7064

Author

Jayakody, B.V.P.L., Murray, F.J., Little, D.C., and Mowjood, M.I.M.

Subjects
Earth Sciences, Aquaculture, Sri Lanka
Abstract

Village tanks are put to a wide range of uses by the rural communities that depend on them for their survival. As the primacy of irrigation has decreased under these tanks due to a variety of climatic and economic reasons there is a need to reevaluate their use for other productive functions. The research presented in this paper is part of a programme investigating the potential to improve the management of living aquatic resources in order to bring benefits to the most marginal groups identified in upper watershed areas. Based on an improved typology of seasonal tanks, the seasonal changes and dynamics of various water quality parameters indicative of nutrient status andfisheries carrying capacity are compared over a period of one year. Indicators of Net (Primary) Productivity (NP): Rates of Dissolved Oxygen (DO) change, Total Suspended Solids (TSS): Total Suspended Volatile solids (TVSS) ratios are the parameters of principle interest. Based on these results a comparative analysis is made on two classes of ‘seasonal’ and ‘semi-seasonal’ tanks. Results indicate a broad correlation in each of these parameters with seasonaltrends in tank hydrology. Highest productivity levels are associated with periods of declining water storage, whilst the lowest levels are associated with the periods of maximum water storage shortly after the NW monsoon. This variation is primarily attributed to dilution effects associated with depth and storage area. During the yalaperiod, encroachment of the surface layer by several species of aquatic macrophyte also has progressively negative impacts on productivity. The most seasonal tanks show wider extremes in seasonal nutrient dynamics, overall, with less favourable conditions than the ‘semi-seasonal’ tanks. Never the less all the tanks can be considered as being highly productive with NP levels comparable to fertilised pond systems for much of the year. This indicates that nutrient status is not likely to be amongst the most important constraints to enhancing fish production.Other potential management improvements based on these results are discussed. [PDF contains 19 pages] Department for International Development, U.K. DFID Aquaculture and Fish Genetics Programme (AFGRP) nstitute of Aquaculture, University of Stirling; University of Peradeniya, Sri Lanka

Published
2002

38. Small-Scale farmer-managed aquaculture in engineered water systems: Critical design and management approaches. Project R7064: Working Paper SL1.1

Author

Murray, F.J. and Little, D.C.

Subjects
Sociology, Aquaculture, Sri Lanka
Abstract

The aims of this paper are twofold. Firstly to characterise rural poverty and to give a broad overview of the agro-ecological, climatic and socio-economic conditions in Sri Lanka which shape poverty. Secondly to present the methodology employed to screen suitable field research areas and the techniques subsequently used to carry out Rapid Rural Appraisal in two upper-watersheds villages. Also presented are details of a concurrent stakeholder analysis that aimed to investigate the capacity of secondary stakeholders to promote sustainable aquaticresource development and to invite their participation in the formulation of a participatory research agenda.[PDF contains 58 pages] Department for International Development, U.K. DFID Aquaculture and Fish Genetics Programme (AFGRP) Institute of Aquaculture, University of Stirling; University of Peradeniya, Sri Lanka; CARE International Sri Lanka

Published
2000

40. The commercial use of chicken processing wastes to raise hybrid catfish (Clarias gariepinus) x Clarias macrocephalus) in Thailand

Author

Little, D.C., Kaewpaiton, K., and Haitook, T.

Subjects
Manure, Catfish culture, Waste utilization, Manure, Catfish culture, Hybrid culture, Thailand, Clarias gariepinus, Clarias macrocephalus, Hybrid culture, jel:Q00, Clarias gariepinus, Clarias macrocephalus, Aquaculture, Thailand, Waste utilization
Abstract

The article highlights the commercial use of chicken processing wastes on nursery and growout operations of hybrid catfish (Clarias gariepinus x Clarias macrocephalus) farm in Thailand.

Published
1994

43. P245

Author

St. Peter, S.D., primary, Valusek, P.A., additional, Little, D.C., additional, Snyder, C.L., additional, Holcomb, G.W., additional, and Ostlie, D.J., additional

Published
2007
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44. Population control in farmed tilapias

Author

Mair, G.C. and Little, D.C.

Subjects
Population control, jel:Q00, Oreochromis, Tilapia culture, Aquaculture, Population control, Tilapia culture, Sex reversal Oreochromis, human activities, Sex reversal
Abstract

Under the majority of culture practices, the reduction or elimination of reproduction in culture ponds results in significantly improved yields of marketable fish. An examination is made of existing methods for the control of reproduction in tilapias (Oreochromis spp.). The generation of all-male tilapia by hormonal sex reversal and genetic manipulation is discussed in detail, indicating the various advantages and disadvantages of both techniques.

Published
1991

47. Development and evaluation of a stress challenge testing methodology for assessment of Nile tilapia (Oreochromis niloticus, Linn.) fry quality.

Author

MacNiven, A.M. and Little, D.C.

Subjects
*NILE tilapia, *FISH physiology
Abstract

Abstract A decline in the quality of the freshwater fish seed available to small-scale farmers in Asia has been identified as an important constraint on the development of aquaculture in the region. There is a need for simple and reliable methods of determining the quality of seed at the farm gate or hatchery. The present study was carried out, in the field, to develop and evaluate a stress challenge test for Nile tilapia (Oreochromis niloticus, Linn.) fry as the effects of stress on fish performance have been well documented and similar tests are used elsewhere in the sector. Formalin and iodized salt were used as reference toxicants. LC[sub 50] values were estimated using mortality figures resulting from exposure of marketable-sized fry to saline and formalin solutions. The two test concentrations, 24 ppt for saline and 500 p.p.m. for formalin, were used as reference toxicants in acute, static bioassays to challenge fry reared under different conditions during the post sex-reversal, nursery period. Using existing farm practice as controls the conditions were: 50% increased stocking density, formalin treatment, 40% reduction in feed rate and no supplementary feed. Fry length proved to be a very significant co-variable; adjusted means showed no significant difference between treatments. The importance of only marketing tilapia fry weighing over 0.2 g was emphasized. It was recommended that the challenge testing approach could be modified, but that it was vulnerable to unquantifiable and uncontrollable factors arising from management and the environment, which may have altered responses to the stressor. [ABSTRACT FROM AUTHOR]

Published
2001
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48. Statistical aspects of aquaculture research: optimum block size in pond experiments.

Author

Smart, T.S., Riley, J., and Little, D.C.

Subjects
POND ecology, AQUACULTURE
Abstract

Abstract The sensitivity of any treatment comparisons in pond experiments is often limited by large variability among ponds. Standard techniques of increasing the number of replicate ponds to account for the large variability may be inappropriate as only a limited number of ponds may be available for any one experiment. This paper considers various ‘balanced incomplete block’ designs and compares their use with ‘completely randomized designs’ and ‘randomized complete block’ designs. With simulated data, it is shown that ‘balanced incomplete block’ designs can reduce the standard error of a treatment estimate by as much as 50%, and reduce confidence intervals by 25%, although increases of similar sizes may be experienced. The pattern of allocation of blocks to ponds by neighbour or by pond number shows no clear distinction in estimation improvement. Where missing ponds occur a large increase in imprecision may be experienced. These results are supported by data from non-uniformity experiments. Further work is needed to explore block structures for specific types of treatment that may influence the patterns of variability to different extents. [ABSTRACT FROM AUTHOR]

Published
2001
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49. Overwintering performance of Nile tilapia Oreochromis niloticus (L.) broodfish and seed at ambient temperatures in northern Vietnam.

Author

Dan, N.C. and Little, D.C.

Subjects
*NILE tilapia, *OVERWINTERING in fishes
Abstract

Abstract Two experiments (E1 and E2) to assess the performance of tilapia broodstock and tilapia sex-reversed fry in overwintering were conducted at the Research Institute for Aquaculture No.1 (RIA-1) in the cold seasons of 1995–96 and 1996–97. Nile tilapia Oreochromis niloticus (L.) broodstock of the Thai, GIFT, Egypt and Viet strains were overwintered in deep and shallow ponds, as well as in deep and shallow hapas suspended in a single deep pond for evaluation of the influence of overwintering systems on the survival and growth of fish. Large (> 1 g) and small (< 1 g) tilapia seed were overwintered in deep hapas-in-ponds for comparison of their performance. In 1995–96, the coldest pond water temperature was 10–11 °C, and survival of tilapia broodfish overwintered in deep and shallow hapas-in-ponds was 99.6–100%. This was significantly (P < 0.05) higher than fish stocked in deep and shallow ponds (74.4–90%). The survival rate of larger monosex tilapia fry was 54%, which was significantly (P < 0.05) higher than that of smaller fry (33.4%). In 1996–97, the lowest pond water temperature was 15.8 °C, and fry showed similarly high survival rates in all treatments (97–100%). There was no significant difference between fry in the two size classes. The results of this study clearly indicate that hapas-in-ponds are useful for reducing the risk and improving the survival of tilapia broodstock and fry in the cold season. Differences in the decline in ambient temperatures year on year mean that the need for special overwintering conditions varies. Hapas-in-ponds are a low-cost overwintering method that can be one of the appropriate strategies for tilapia seed production under the variable, cool temperature regimes in northern Vietnam. [ABSTRACT FROM AUTHOR]

Published
2000
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