No description available.

No description available.

To prevent disease outbreaks and increase competitiveness of U.S. shrimp products, U.S. aquaculture researchers have developed super-intensive, bio-secure, recirculating shrimp production systems since the early 1990s. The general objective of this research is to determine an optimal production strategy to maximize the net revenue for the system. An inventory optimization model was built to determine the optimal harvesting week, shrimp size, and number of crops per year for experimental trials conducted at the Gulf Coast Research Laboratory (Ocean Springs, MS), the Waddell Maricultural Center (Bluffton, SC), and the Oceanic Institute (Oahu, HI). Survival rate and selling price sensitivity analyses were conducted to see their impact on the system¡¯s net revenue. The optimal harvesting week solved by this model is determined by shrimp growth and feed functions. Producer selling price and survival rate can affect the value of net revenue, but do not impact the optimal harvesting week. Shrimp producers can use the developed inventory optimization model and results to efficiently manage their operations.

No description available.

This dissertation examines the shrimp industry in the Gulf of California from a political ecology perspective. The interaction between fishermen and their marine environment is explored, as well as the historical factors that led to vastly different types of fishermen in the communities of Guaymas and Empalme. Some have specialized in the harvesting of shrimp; others are diversified, multiple species fishermen. Some are highly industrialized offshore shrimpers; others are small-scale fishermen, more modest in their technology but more resilient when facing the current crisis in the shrimp industry. The underlaying causes of this crisis are explored by looking at state development policies, the assumptions behind fisheries management, and the configuration of markets. These have all emphasized specialization in the production of shrimp while ignoring the high interannual variability characteristic of shrimp populations. The end result: an overcapitalized, overexpanded industry and a possible overexploitation of shrimp stocks. Rather than addressing the root causes of the crisis, recent policies have instead transferred rights to the offshore fishery from cooperatives to private investors. At the same time there has been a concerted attack against small-scale producers. It is believed that by getting rid of this sector, catch per boat in the offshore sector will increase and overall "efficiency" will be improved. I compare industrialized trawlers and the small-scale sector and argue that the latter is currently producing high quality shrimp at lower monetary and ecological costs. But small-scale fishing is not equated with sustainability. Instead, differences among small-scale fishermen are analyzed. I contend that those who belong to traditional fishing families and have access to collective knowledge about the marine environment that has accumulated through generations, are better able to deal with a highly unpredictable environment and minimize risk. Those who do not have access to this knowledge have specialized in the harvesting of shrimp. I argue that a strategy of diversification is both more profitable in the short-term and sustainable in the long-run. Avoidance strategies among small-scale fishermen in response to externally imposed regulations are also examined. Fishermen are analyzed as individual profit maximizers and as community members who break the rules to serve collective interests. Just as individuals act collectively to deal with an unpredictable environment, they also act collectively to effectively challenge the institutions of rule-making.

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°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°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.

by Siu-ming Chan. / Bibliography: leaves 247-259 / Thesis (M.Ph.)-- Chinese University of Hong Kong, 1984

by Wo-wing Cheng. / Thesis (M. Phil.)--Chinese University of Hong Kong, 1981. / Bibliography: l. 265-272.

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.

The effects of unilateral eyestalk ablation, diets and sex ratios were evaluated on two wild populations of Farfantepenaeus aztecus in a closed recirculating maturation system. Ovarian development and spawning frequencies of ablated females in both studies were higher than the non-ablated females. Replacement of bloodworms in maturation diet with enriched adult Artemia sp. had no negative effect on the number of eggs spawned and resulted in increased hatch and survival rates from Nauplius I to Zoea I. Life span of ablated females fed enriched Artemia sp. was longer than ablated females fed bloodworms. Replacement of the expensive bloodworm diet component with adult enriched Artemia sp. is possible without negative impact on female reproductive performance. Reducing male to female ratio from 2:1 to 1:1 resulted in a 1.25% decrease in spawning activities of ablated females. The life cycle of pond-raised F1 generation F. aztecus also was completed in the closed recirculating system using unilateral eyestalk ablation as previously described. This study found diets that contained an enriched adult Artemia sp. component performed superior (i.e. hatch rate, nauplii and zoea production) to a diet containing bloodworms. Six consecutive larval rearing trials evaluated changes in select water quality indicators and their effect on growth, survival, and stress tolerance of F. aztecus postlarvae cultured in artificial seawater under closed recirculating and flow-through conditions. The closed recirculating larval rearing system successfully produced five-day-old postlarvae (PL) from Zoea I (Z1) with similar dry weights, lengths and stress resistance to PL produced under standard water exchange practices. The trickling biofilters were found to be a limiting component of this system. A submerged coral biofilter was added to the system and effectively processed culture water for re-use. Addition of the submerged biofilter resulted in improved survival rates in Trials 4, 5 and 6. These studies demonstrate maturation and larval rearing of F. aztecus is feasible in closed recirculating systems. Implementation of these systems in hatcheries bolsters biosecurity while reducing the environmental impact of hatchery effluent. Recirculating and re-use systems are therefore essential in the further development of sustainable hatchery programs for endemic species.