This thesis is concerned with social and economic aspects of freshwater prawn (Macrobrachium rosenbergii) culture development in converted paddy field gher systems in SW Bangladesh, based on economic features of prawn production and social impacts within and around prawn farming communities. Based on a sample of 400 farmers from the four different zones in Bagerhat district in SW Bangladesh, 345 (86.25%) cultured prawn with fish and rice in their gher. The culture period is typically nine months, wild fry are stocked when available in May-June and harvested from November to January. A variety of feeds are used but the preferred material is the freshwater snail, Pila globosa. Productivity is variable, averaging 432 kg ha-!. The freshwater prawn is a highly valued product for international markets and is therefore almost all exported. All farmers in all zones and different gher size categories made a profit, with seed and feed dominating variable costs. Considerable variation in production costs and profitability was observed. The culture of prawn in gher systems is technically possible in a variety of conditions though expanding small scale of farming mainly depends on reducing production costs. Future targets could be to integrate with other agricultural activities especially dike cropping and rice production in the monsoon. The livelihoods of a large number of people are associated with prawn farming. Four different fry, snail and prawn markets were surveyed, including a sample of 60 fry catchers, 40 fry traders, 75 snail collectors, 40 snail traders and 40 prawn traders. A sample of 200 women, associated with gher farms was also surveyed. In spite of socio-economic constraints, most of the households of farmers (81 %) have improved their status through prawn farming where prawn have brought out clearly positive changes of economic activities and generated new employment. All appeared to have gained from their activities, women have enhanced their position in families and societies. However, concerns arise about the long-term sustainability of prawn farming due to high production costs, low supply of wild fry and snail meat, poor natural resources, poor institutional support and inadequate extension services, all of which have affected sustainable livelihoods of farmers and associated groups. It may necessary to establish local ingredients feed industries, prawn hatcheries and to provide low-interest credit with institutional and policy support for sustainable gher farming.

Thesis (Ph. D.)--University of Hong Kong, 1992.

Made available in DSpace on 2014-06-11T19:22:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-02-22Bitstream added on 2014-06-13T20:48:49Z : No. of bitstreams: 1 henares_mnp_me_jabo.pdf: 553873 bytes, checksum: 3b0cf11a9bc723ffcb29039f64e16c5f (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Esta dissertação de mestrado está organizada em três capítulos. O capítulo I apresenta uma introdução geral, onde são abordados os impactos ambientais provocados pela atividade da aqüicultura e o tratamento de efluente por wetlands construídas. O capítulo II e III são referentes à experimentos desenvolvidos no Setor de Carcinicultura do Centro de Aqüicultura da UNESP (CAUNESP), em Jaboticabal – SP. Os principais objetivos destes capítulos foram: (Capítulo II) determinar os possíveis impactos provocados pelo manejo utilizado para a manutenção de camarões reprodutores da espécie Macrobrachium rosenbergii na água utilizada no viveiro; (Capítulo III) avaliar a eficiência de uma wetland construída e povoada com duas espécies de macrófitas aquáticas flutuantes (Eichhornia crassipes e Salvinia molesta) com diferentes exigências nutricionais para otimizar o tratamento do efluente de viveiro de manutenção de reprodutores de M. rosenbergii. O resultado do Capítulo II permite concluir que o manejo realizado para a manutenção de camarões reprodutores da espécie Macrobrachium rosenbergii entre as biomassas de 403,18 e 547,90 g.m-2, durante o período de 50 dias, provoca o aumento dos valores de condutividade elétrica, pH, turbidez e MPS; das concentrações de NIT, NT, P-PO4, PD e PT e reduz a concentração de O2 dissolvido. No Capítulo III, concluiu-se que a wetland construída e povoada com S. molesta e com E. crassipes + S. molesta foram menos eficiente no tratamento do efluente de viveiro de manutenção de M. rosenbergii do que a wetland construída e povoada com E. crassipes. / The world production of Malaysia shrimp, Macrobrachium rosenbergii, presented considerable growth in the last decades. However, shrimp farming activity can provoke impacts in water used in the vivarium. The aim of this work was to determine the possible impacts provoked by the management accomplished for the maintenance of reproductive shrimp of the species M. rosenbergii in water used in the vivarium during the period 50 day. In the beginning of the experiment (03/14/2007) the vivarium, located in the CAUNESP, in Jaboticabal (SP-Brazil), with 193 m2 of surface and 1.1 m was full of 1.263 reproductive shrimp with medium weight of 61.61 ± 16.55 g.indivíduo-1. Weekly, it was determined value of temperature, pH, dissolved oxygen, electric conductivity, total alkalinity, turbidity, particulate material in suspension (PMS), total inorganic nitrogen (TIN), total nitrogen (TN), orthophosphate (P-PO4), dissolved phosphorus (DP) and total phosohorus (TP) of supply water and of the effluent of the vivarium. The values of electric conductivity and pH were significantly (p<0,05) higher in the effluent relation to the ones of the supply water. The 25 turbidity and PMS values were significantly higher in the effluent of the vivarium in seven weeks. Except for the dissolved oxygen and of TN, the TIN, P-PO4, DP and TP concentrations were significantly higher in the effluent when compared to the supplu water of vivarium in all the weeks evaluated. Among the forms of phosphorus, the biggest increases were observed for DP and and TP concentrations with 82.76 μg.L-1 and 174.75 μg.L-1, respectively. Among nitrogeneous forms, the biggest increase was observed for TIN with 81.32 μg.L-1. The management accomplished for the reproductive maintenance of M. rosenbergii during the period 50 days caused impact in water used in the vivarium... (Complete abstract, click electronic access below)

Foi desenvolvido um método de recuperação de proteína de cefalotórax de camarão-rosa (Penaeus brasiliensis e Penaeus paulensis), tendo como base a separação física e a insolubilização por precipitação isoelétrica (pH 4,5) e aquecimento (70-75&#176;C/5min), caracterizando-se posteriormente o produto obtido e o resíduo sólido resultante. O método empregado propiciou um rendimento de cerca de 2% e a proteína recuperada mostrou-se acompanhada de reduzida quantidade de cálcio (0,03%) e quitina (0,5%) e de níveis de metais tóxicos (Hg, Cd, Pb, Cu e Zn) muito abaixo de limites permitidos em alimentos. Com base no cômputo químico dos amino ácidos essenciais, a proteína obtida apresentou uma qualidade nutricional de 54% e de 90%, em relação à caseína e à proteína da F.A.O/O.M.S, respectivamente, limitada primariamente pelo triptofano. A eficiência desta proteína em promover o crescimento dos animais foi de 81%, comparada à caseína, prejudicada parcialmente por sua digestibilidade (78%). A solubilidade da proteína estudada foi baixa a pH 7 (8,70%) e pôde ser melhorada (20 a 97,5%) através de tratamento alcalino e/ou eliminação do aquecimento na recuperação da mesma. Sua capacidade de emulsificação foi de 31% a 125% comparada à da proteína de soja comercial (Proteimax 90 HG), quando adotou-se também o tratamento alcalino e/ou a eliminação do aquecimento na sua recuperação. Com base no cômputo químico dos amino ácidos essenciais, a qualidade nutricional da proteína do residuo foi de 21% e de 35%, respectivamente em relação à caseína e à proteína da F.A.O/0.M.S., com limitação primária em triptofano. O rendimento em quitina e em quitosana atingiu 2,7g e 2,5g a partir do resíduo equivalente a 100g de cefalotórax ou 29g e 26g para cada 100g do mesmo, respectivamente. / A method for the protein recuperation from pink shrimp (Penaeus brasilensis and Penaeus palensis) cephalotorax was developed and the recuperated product and generated solid waste were characterized. The physical separation and protein insolubilization by isoelectric precipitation (pH4,5) and heating (70-75&#176;C/5min) were the base of this method. The method promoted a yie1d of 2% and the protein product showed low quantities of calcium (0,03%) and chitin (0,5%) and very low quantities of toxic metals (Hg, Cd, Pb, Cu and Zn) in relation to limits permited in foods. Based on the essential amino acids chemical score the recuperated protein showed a nutritional quality of 54% and 90%, compared to casein and F.A.O/O.M.S reference protein, respectively, primarily limited in triptophan. The eficiency of this protein in animal growth promotion was of 81% in relation to casein, limited partially by its digestibility (78%). The solubilty of the protein was low at pH 7 (8,70%) and was improved (20 to 97,5%) through the alkaline treatment and/or heating elimination in its recuperation. The emulsification capacity of this protein was from 31% to 125% campared to commercial say protein (Proteimax 90 HG) when the a1ka1ine treatment and/or heating elimination was also used. Accarding to the essential amino acids chemical score the protein nutritional quality of the solid waste was of 21% and 35% respectively, in relation to casein and F.A.O/O.M.S. reference proteint with primary limitation in triptophan. The yield in chitin and chitosan was 2,7g and 2,5g/100g cephalotorax or 29g and 26g/100g solid waste, respectively.

The overarching aim of this research was to improve understanding of the synergies and trade-offs between economic and domestic food security benefits associated export-oriented shrimp and prawn aquaculture in a fragile developing country environmental context. The research scope covers the entire ‘seafood system’ incorporating production, distribution, trading and consumption in the south-west coastal region under greater Khulna District, Bangladesh. The primary research objective was to understand causal factors in variation of seafood nutritional quality and health outcomes, exploring correlations with seafood consumption across a range of agro-ecological, aquatic farming systems and socio-economic conditions. The study also focused on differences in intra-household allocation with a special focus on adolescent girls, being amongst the most vulnerable members of society. These objectives necessitated a highly inter-disciplinary approach to understand complex interactions between biophysical aspects (e.g. where and which species are most effective in supplying essential nutrients) and the social norms of food allocation. Fieldwork was conducted in Satkhira, Khulna, and Bagerhat Districts of Khulna Province over 17 months during 2012 to 2015. Four villages across a peak-annual surface water salinity gradient; high saline (>10 ppt), medium saline (>5<10 ppt), low saline (<5 ppt) and freshwater (<0.5 ppt) were selected for case-studies. The thesis begins with a literature review of the evolution of shrimp and prawn farming in Bangladesh and the wider region and identification of knowledge gaps. Research resolved from district to community to household level. Key informant (KI) interviews were used to establish well-being criteria (based on a range of 5 social and economic assets) at community level. In each community a census of households (n=1082 households) were derived from the same interviews and KIs asked to ranked households on the established well-being criteria. Results were validated through a short interview of all the identified households (HH). This sample-frame provided the based for two concurrent survey efforts. Stratified-random selection of 160 HH on two well-being categories (better-off and worse-off) for ‘farm level’ analysis using a semi-structured questionnaire. Key topics included inputs/outputs characteristics, economic benefits and the fate of farmed products were evaluated. Another 240 households with single adolescent girls were selected from the same frame, again with randomized-stratified sampling based on well-being categories for ‘intra-household’ analysis. This resulted in selection of 60 HH per community consisting of 30 ‘better-off’ and 30 worse-off households (further analysis was conducted on a range of secondary sampling outcomes based on livelihood options, intra-household food distribution and aquatic farming assets). A 24-hour food recall method, food frequency questionnaire, food photography and measuring cup sets were used to estimate individual members’ food consumption at the household level. Anthropometric measures (stunting, wasting, BMI, MUAC) and biomarkers (omega-3 index in RBC and LC n-3 PUFA/LC PUFA in whole blood cell) were used to assess food security outcomes of adolescent girls (n=200 subject). In an entirely separate effort, samples of shrimp/prawn and fish polyculture species (57 species and 9 by-products, 1 live feed; n=672) were collected from the major agro-ecologies (four saline gradients; HS, MS, LS and FW) and culture systems (extensive, semi-intensive, intensive, organic and pocket gher). At least 3 sites from each saline gradient (3×4=12 sites) were selected for sampling and pooled samples to represent all the culture system in the region. The major macro and micronutrients of the collected species were analysed and these datasets were used to know the nutritional distribution among the family members in household level study. Two aggregate indices of wealth (or well-being) and aquaculture were developed based on a range of quantitative (ordinal and interval) measures. Principle Component Analysis (PCA) was used to understand how aquaculture influences on wealth gain. Wealth index of the same social well-being did not differ among the agro-ecologies. However, the aquaculture index was varied in agro-ecologies. Most of the households (60-80%) were involved directly in aquaculture however, a majority portion of the households was worse-off (48-64%). Both HS and LS area had more livelihood options due to their proximity to mangrove forest Sundarbans and city amenities, respectively compared to MS and FW area. Ownership of the land did not influence any involvement in aquaculture and yields but he willingness and risk-absorbing capacity of the farmers were the main factor to get involve in aqauculture. In aquatic farming system the importance of export-oriented shellfish yield gradually decreased from HS to FW area (55-20% by volume). The intentional stocking of finfish and PLs were common across the saline areas however the wild caught juveniles and hatchery originated fingerlings were usual in higher and lower saline areas, respectively. The low priced tilapia took the place of wild recruited mangrove fishes in MS area. Diseases, especially the devastating white spot virus (WSSV), frequency were higher in higher saline areas. The indicators like wild recruitment, salinity, water productivity and water management also a vital factor to gain yield. The integration of aquatic and terrestrial crops (rice and dyke crop) in the lower saline areas provide higher yield compared to higher saline areas. However, the net economic returns were largely determined by the aquatic products. The income of ghers in FW and MS area was sensitive to the lower prices of freshwater finfish and tilapia. The protein content in shellfish was higher than the other finfish, however, lower in other essential nutrients. Species living in the higher saline areas contained higher total n-3 PUFA (in weight) and LC n-3 PUFA/LC-PUFA compared to the same species living in lower saline areas. Small Indigenous Species (SIS) and Self-Recruiting Species (SRS) were proven to provide higher micronutrients and total n-3 PUFA than larger fish. Seafood that destined for the international markets contained less n-3 PUFA and micronutrients in comparison to the domestically consumed fish. Customary intra-household food distribution disparity (mainly fish) still exists at household levels where females, especially adolescent girls, were deprived. Fish consumption (>77 g /capita/day) and fish originated protein supply (>25% of total protein intake) was higher than the other part of Bangladesh. The protein consumption of adolescents was 2-3 times higher than the Recommended Nutritional Intake (RNI). However, the energy intake was lower than the required level. High protein, low energy consumption was not reflected in body mass. Micronutrients (zinc) consumption was above the RNI level. However, iron and calcium consumption was less than the RNI. The n-3 PUFA in RBC of adolescent girls accurately reflected their access to, and availability of, oily fish. In the omega-3 index (n-3 PUFA in red blood cell) both HS and MS areas, adolescent females were in the intermediate stage (4-8%), and rest of the two areas were in the undesirable stage (<4%). The n-3 LC-PUFA was around 20-30% of total LC-PUFA content in whole blood and gradually decreased from higher saline to lower saline areas. The thesis concludes that the gher based aquatic animal farming in S-W Bangladesh is a dynamic system operated by both rich and poor. The salinity level and the presence of mangrove forest make the farming system dynamic. The holistic scenario suggested aquaculture in ghers is a family driven small scale polyculture where varieties of aquatic foods are produced both for global and local value chain. Higher amounts of valued products (both in terms of nutrition and price), less disease susceptibility, more alternative livelihood options both in HS and LS were found in better position than the other two sites, however the nutritional content of fish and its manifestation in adolescents strongly mirrors agro-ecologies irrespective of social position of households. The thesis provides an important, grounded importance of the system and the linkage of the community people for livelihoods, food production and food security. The dynamic systems were understood and effective messages formulated for the policy makers. In doing so, the thesis contributes to an understanding of how small-scale polyculture equally benefited local food security and macroeconomic growth of a developing country.

Throughout this thesis I have laid out several factors that have contributed to the sustainability of shrimp farming in Thailand, and if sustainability whilst maintaining production can ever be achieved. To find out the current situation of shrimp farming in Thailand, the history of global and Thai shrimp farming is described. The social and environmental problems of the unsustainable history of shrimp farming in Thailand is then considered. Solutions to these effects conclude that it is up to the consumer to demand for better regulations from the government and the shrimp companies to ensure a sustainable future for shrimp farming both globally and in Thailand.

Limited water exchange shrimp culture technology is commonly used today in many shrimp farms in Vietnam to reduce water usage, input of diseases and discharge of nutrient-rich effluents into environment as well as to increase the production per unit area. However, a remaining problem in this technology is that the water quality in shrimp ponds will be reduced due to limitation of water exchange for a long period. The accumulation of inorganic components such as waste feed, bacterial deposits or other biological debris at the pond bottom will lead to low dissolved oxygen, high ammonia-nitrogen level, high fecal coliform bacteria and high turbidity which cause a severe degradation of water quality and detriment to shrimp growth and survival. To solve this remaining problem, an autonomous water-cleaning machine for shrimp ponds was designed to control the waste accumulation in the pond. This is an effective solution to replace manual cleaning methods for water quality management in shrimp farming in the coastal area of the Mekong delta of Vietnam. Especially, this technique can be used for biosecure shrimp production systems according to GMP standards to meet the objectives for sustainable development of shrimp aquaculture in Vietnam. / Kỹ thuật nuôi tôm không thay nước đang được sử dụng rộng rãi ở các trại nuôi tôm Việt Nam vì giúp giảm lượng nước sử dụng, hạn chế thải nước vào môi trường và giúp tăng diện tích nuôi trồng tôm. Tuy nhiên, bản thân kỹ thuật này cũng tạo nên một sản phẩm chất thải là phân tôm, thức ăn và chế phẩm sinh học xử lý nước dư thừa. Chất thải này dần dần tích tụ dưới đáy ao tạo thành lớp bùn độc, rất thiếu ôxy và chứa nhiều chất gây hại như ammonia, nitrite, hydrogen sulfide. Để tránh làm giảm diện tích ao nuôi do chất thải tích tụ làm tôm lảng tránh và tăng mật độ tôm nuôi trồng, thiết bị tự hành thu gom chất thải làm sạch nước trong vuông nuôi tôm đã được nghiên cứu, thiết kế và chế tạo thành công. Thiết bị đã thay thế các hoạt động làm sạch chất thải thủ công của con người, không sử dụng các nguồn năng lượng gây ô nhiễm, giảm nhu cầu về điện góp phần phát triển sản xuất tôm sạch đạt chuẩn GMP và phát triển bền vững ở các tỉnh ven biển miền Tây Việt Nam.

No description available.

Litopenaeus vannamei or Pacific white shrimp is the most widely farmed crustacean in the world. Shrimp are commonly fed feed containing 30-40% soybean meal or other plant-based feeds that are more economically and environmentally sustainable than animal-based feed. However, plant-based pellets are less palatable and less chemically attractive compared to animal material. Based on that, current research and practice includes the addition of specific marine animal meals in order to enhance palatability and attractability of plant-based shrimp feed. Yet, it is not sustainable or economically achievable to continue relying on marine animal meal. In the herein study, the effect of proprietary chemical mixtures designed by our research group as feed additives was examined based on their attractability and palatability in comparison to krill meal, a highly attractive and palatable supplement for shrimp feed. In palatability assays, total amount of pellets was measured before and after one-hour and three-hour periods of feeding in group-housed animals. In attractability assays, responses of shrimp were measured based on the number of probes and grabs on the source (airstone) of the stimulus being released. Each diet-set used contained different concentrations of krill meal and synthetic chemical mixtures. Results demonstrated these chemical mixtures enhance attractability and palatability of soybean based feed in L. vannamei when compared to krill meal. Furthermore, the addition of a proprietary mixture (= “premix”) improved responses in the attractability assays when compared to stimuli that did not contain the premix. Overall, results support the hypothesis that synthetic chemical mixtures can improve palatability and attractability of soybean meal based shrimp feed. This work could provide a reference for the development of synthetic chemoattractants and chemopallatants for the aquaculture of shrimp.

No description available.