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This study has examined consumers’ acceptance, preference, and willingness to pay (WTP) for five newly developed convenient (ready-to-cook) catfish products. The University of Arkansas at Pine Bluf...

The U.S. catfish aquaculture industry has undergone a continuous and alarming contraction over the last 15 years or so. The rapid increase in cheaper imports, which has coincided with the decline i...

Carp polyculture emerged as a promising practice for the development of aquaculture in Bangladesh in recent years. However, the economic potentiality of carp polyculture relied on the profitability and inputs use pattern. Therefore, this study investigated the economic viability of carp polyculture farming, particularly focused on profitability, profit sensitivity, economies of scale, and liquidity. A survey was conducted using a structured questionnaire to gather cross-sectional data, which included 183 randomly selected carp polyculture farmers from five districts in Bangladesh. Descriptive and econometric analysis was adopted to evaluate the economic performance of the carp polyculture system. The results showed that feed was the most important production input since it accounted for a major share of operating costs (57.3%). Freshwater carp polyculture farming was generally found profitable, although the profit was considerably sensitive with the alteration of feed price and fish price. Economies of scale were evident in this study, where the farm operated in economies of scale had lower productivity but greater cost efficiency. However, some inputs were inefficiently used by the diseconomies scale of farms, which led them to loss of return even though they had higher productivity. High cash flow coverage ratio due to higher yield strategies and low debt-servicing ratios were found, indicating lower liquidity risk for carp polyculture farming. Based on the present findings, it is suggested that farmers should pay more attention to the efficient use of inputs to facilitate a greater cost efficiency, continual cash flow, and sustainable increase in fish production.

Volatility in catfish pond bank and feed prices lead to profit uncertainty in the catfish industry. Analysis of the factors that affect those prices and development of a forecasting model would pro...

The stringency of the regulatory environment has been shown to negatively affect the growth of aquaculture. A technical efficiency analysis of baitfish/sportfish production in the United States was...

Increased understanding of trends in supermarket sales of seafood and fish has potential to assist the U.S. aquaculture industry to refine marketing strategies and target markets. This article focuses on understanding the marketing of seafood products in grocery retail stores with special emphasis on four major southern aquaculture products (catfish, shrimp, clams and crawfish). The study used store-based as well as household-based scanner data from the Nielsen Company. Results show that frozen/chilled finfish sales (in value) are increasing faster than total frozen seafood sales. Shrimp is the major type of frozen seafood sold in the United States. Among unbreaded finfish, tilapia, whiting, salmon, catfish and flounder occupied the top five ranks in terms of cumulative 5-year sales from 2005–06 to 2009–10. The share of tilapia in retail markets has risen consistently and steeply over the years. Sales performance of products in a market is correlated positively with the degree of promotional prici...

Context: Water productivity is considered as an important indicator of Agriculture productivity because of the scarcity of freshwater. More yield or output against same or less amount of water has become the global interest. Objectives: This study measures the productivity of water on the floodplain land in terms of Boro rice cultivation for two floodplain beels in Rajshahi Bangladesh. Materials & Methods: For this study, the production and market price data were collected by direct observation based on 30 samples in the year 2006-07. Results: This study found gross water productivity of rice yield as 0.47 kg m -3 in beel Mail and 0.43 kg m -3 in beel Chandpur. In monetary value, water productivity per cubic meter irrigation water were TK 5.65, TK 3.42 and TK 2.64 based on gross return, net return considering cash costs and net return considering full costs in beel Mail. In beel Chandpur these values were TK 5.19 m -3 , TK 2.87 m -3 and TK 2.14 m -3 , respectively. The usage of average irrigated water in the boro rice farms were estimated 10730.05 m -3 and 11236 m -3 with an average production of yield 4992.95 kg and 4783.20 kg in beel Mail and beel Chandpur. Statistical result shows that keeping irrigation water constant, a 1% increase of boro rice yield will increase water productivity at 0.916% in beel Mail and 0.972% in beel Chandpur. The water productivity in beel Mail was 4.65% higher than beel Chandpur due to the intervention of community based fish culture management. Conclusion: The findings of this study will help to govern and improve production by proper utilizing floodplain lands. DOI: http://dx.doi.org/10.3329/jbs.v21i0.22526 J. bio-sci. 21: 123-136, 2013

Capture fisheries and aquaculture sectors have played major roles in the national economy and food security of Fiji. But climate change may place substantial stress on these sectors within this archipelago. This paper assesses the potential economic impact of two important climate change adaptation strategies in Fiji, natural resource management (NRM) and aquaculture, using a market fish supply–demand model. The model undertakes a comparative analysis of alternative fisheries development scenarios for 2035 and 2050, while taking account of the impact of climate change on the fisheries sector. The modeling and scenario analyses show that promoting aquaculture can help raise aggregate fish production, consumption, and trade. However, the required increases in aquaculture could be massive. While aquaculture development alone is unlikely to meet the growing excess demand for fish in Fiji, it will be an important component in adapting to the negative effects of climate change on capture fisheries. Various NRM strategies, such as marine protected areas (MPAs) and locally managed marine areas (LMMAs), are projected to have positive impacts in Fiji, expanding the stock and catch of fish. But current efforts on various NRM strategies are too small to have any meaningful impact to reverse the declining trends of coastal fisheries catch. Efforts would need to be greatly scaled-up to achieve significant production gains.

The fisheries sectors in Vanuatu and Timor-Leste are important sources of food and income. Similar to other developing countries and those in the Pacific, they are vulnerable to the impacts of climate change more so because of their geographic location, socioeconomic conditions and political instability. Nonetheless, there are approaches to alleviate the damaging effects of climate change in the region's fisheries sector. Using economic modeling, this paper estimates the economic costs of potential climate change adaptation strategies for the fisheries sector in Vanuatu and Timor-Leste through assessment of alternative future scenarios. Strategies include aquaculture development, natural resource management through establishment and/or expansion of marine protected areas, and deployment of low-cost inshore fish aggregating devices. Modeling results demonstrate that the above innovations will enable the two countries to significantly improve coastal and freshwater fish production in the medium-term (2035) and long-term (2050). Fish consumption is projected to grow due to population and income improvements; yet considerable increases in production will augment demand. Furthermore, national-level gains are projected from these adaptation strategies through fish exports. Improved production under climate change will require significant investments from the national governments of Vanuatu and Timor-Leste and/or private sectors.

Pacific Island countries face food insecurity, limited availability of productive agricultural land, and deteriorating coastal and marine biodiversity where communities rely on these resources for food and economic sustainability. Climate change further impends these Pacific Island countries, jeopardizing land and aquatic ecosystems in addition to threatening the livelihoods and socioeconomic conditions of coastal communities. The national governments of Pacific Island countries have created a number of development policies and plans to enhance the economic conditions, safety assurance, environmental conservation and preservation and other critical requirements of the national populace. This first paper in this Special Section aims to present the economic contributions, types of fisheries and common fishing practices/gears, and the institutional set-up and the national development plans and policies related to the fisheries sector in four Pacific countries namely, Fiji, Solomon Islands, Vanuatu, and Timor-Leste. The paper discusses the common issues and the collective action surrounding the fisheries sector in these Pacific countries. The final section of the paper provides conclusions based on the findings of the four subsequent papers of this Special Section.

This paper presents a supply-and-demand model for the fisheries sector developed to assess the effect of climate change and related adaptation strategies in four Pacific coral triangle (CT) countries—Fiji, Solomon Islands, Timor-Leste, and Vanuatu. The modeling approach used in this paper represents climate change in terms of supply shocks, and works out its economic consequences using the microeconomic tools of supply and demand. The analysis has considered three time periods: current (represented by the average data of the three most recent available years 2006–2009), medium term (2035), and long term (2050). The study covers all fisheries and aquaculture species, grouped into six key subsectors: tuna, other oceanic finfish, coastal finfish, coastal invertebrates, freshwater finfish, and freshwater invertebrates. Results of the baseline model indicate that with rising per capita income and population, fish demand is expected to increase substantially up to 2050. In contrast to significant growth in fish demand, growth in domestic fish production is projected to be slow due to climate change and other constraints. There is a strong likelihood that many Pacific countries will become large net importers of fish under the baseline scenario (i.e., without implementing climate change adaptation strategies). Likewise, per capita consumption of domestically produced fish is projected to decline under the baseline scenario.

Fisheries resources play a major role in the national economy and to food security in Solomon Islands. Climate change is likely to have a substantial impact on fish production that can lead to a fragile food security condition in the country. This paper assesses the potential economic impact of three important climate change adaptation strategies – natural resource management (NRM), fish aggregating devices (FAD) and aquaculture – in Solomon Islands. The study used a country-specific partial equilibrium economic model with six fish sub-sectors and analyzed potential impact of alternate climate change adaptation strategies for 2035 and 2050. The modeling and scenario analyses show that total fish demand is likely to surpass domestic fish production in 2050. Without appropriate climate adaptation strategy, per capita consumption of domestically produced fish will decline, which has serious negative food security implications for the country. The economic (welfare) analysis conducted based on modeling results show that the national level net economic gains due to climate change adaptation strategies are substantial. If cost and topographic conditions permit, low-cost inshore FADs are expected to be a good mechanism for augmenting domestic supplies of tuna and similar species in Solomon Islands.

Market size requirements for catfish change periodically, and catfish farmers must adjust quickly. Data from catfish pond studies at the University of Arkansas at Pine Bluff (UAPB) were used to develop mathematical models of catfish foodfish in multiple-batch culture across a variety of management alternatives. Two different functional forms (Cobb–Douglas and a modified translog) were each developed into average and stochastic frontier models. Inefficiency terms were found to be non-significant in the frontier models, thus making the average and frontier models equivalent. In the average regression models, the modified translog form demonstrated superior statistical values as compared to the Cobb–Douglas form, but the latter resulted in lower prediction error and was validated with the Chow test when used to predict observations from commercial catfish farms. This approach appears to have merit from the perspective of its statistical properties, and represents a step towards development of a model that co...

Seafood sector can contribute to the global food supply in an important way, and provide an important source of animal protein. Based on observed regional trends in seafood production and consumption and using a global, partial-equilibrium, multi-market model, this study investigates what the global seafood market may look like in 2030. The model projects that the total fish supply will increase from 154 million tons in 2011 to 186 million tons in 2030, with aquaculture entirely responsible for the increase. The fastest aquaculture growth is expected for tilapia and shrimp, while the largest expansion is expected in India, Latin America and Caribbean and Southeast Asia. Fast-growing seafood demand in China and elsewhere represents a critical opportunity for global fisheries and aquaculture to improve their management and achieve sustainable seafood economy.

Asian ethnic fish markets in the Northeastern region of the United States of America (USA) are popular for selling live fish and seafood. A consumer survey was conducted in selected supermarkets of New York, New Jersey, and Pennsylvania during the summer of 2009 to assess consumer preferences for live seafood species. A binary logit model was developed to study the factors influencing preferences for live and fresh fish products. Results indicated that consumer preferences for live fish species vary by ethnic group. Live fish customers visited supermarkets at least two to three times a week and spent $16 to $20 a week to purchase medium size fish (0 to .91 kg live fish, on average). Freshness and appearance (bright, free of bruises, healthy fish) were the most important attributes. Findings indicate that promotion of live fish sales should be targeted to those stores dominated by East Asian (Chinese, Korean, and Japanese) customers.

We have examined the presence of price transmission asymmetry along the value chain, and the price transmission across four main aquaculture species in Thai fish market using monthly data from January 2001 to October 2010. This is an attempt to contribute to the literature on horizontal and vertical price transmission in the seafood markets including the price transmission asymmetry in the developing countries. We did not find any evidence of asymmetric price transmission in walking catfish (except in long-run), vannamei shrimp and tilapia; however, it is evident in Thai Asian sea bass market; wholesalers exercising some market power. In general, price of one species is not found to significantly affect price of the other species at the same level of value chain.

This special issue of Aquaculture Economics and Management (UAQM) features seven articles based on the findings of a recently completed project of the Food and Agricultural Organization of the Unit...

This article centers on an FAO project that focused on price transmission in fishery and aquaculture value chains, and the research conducted via case studies in 14 developed and developing countries. A brief overview of the project with the methodology of analysis and findings for each country is summarized in this work. In addition, general policy recommendations that emerged as key themes across all value chains are discussed. Across all case studies, it was found that relative to other players in the value chain, small-scale fishers and fish farmers are receiving the smallest economic benefits for their products. Processors and retail markets were found to be receiving more of the distributional benefits of the value chain owing to their stronger bargaining power. With this finding, policy recommendations aim to safeguard the interests of small-scale fishers and fish farmers by improving their prices and margins while allowing the resource to achieve long-term sustainability from an economic, social a...

There is a general concern among policy makers that seafood prices may not be proportional along the value chains in Bangladesh. This article investigates causal and price transmission relationships between wholesale and retail prices for five fish species in Bangladesh that include: hilsa (Tenualosa ilisha), rohu (Labeo rohita), catla (Catla catla), pangas (Pangasius hypophthalmus), and tilapia (Oreochromis mossambicus/O. niloticus). Causal relationships between wholesale and retail prices were tested using the Granger causality test while asymmetries in price transmission were examined using the Houck and Ward approach as well as the error-correction approach. The results show that the direction of causality in prices was from retail to wholesale in many of the value chains analyzed, indicating influence of retail price on wholesale price in the Bangladesh fish sector. In general, the price transmission was found to be symmetric in the short-run while a mix of symmetric and asymmetric in the long-run. T...

Aquaculture now supplies half of the fish consumed directly by humans. We evaluate whether aquaculture, given current patterns of production and distribution, supports the needs of poor and food-insecure populations throughout the world. We begin by identifying 41 seafood-reliant nutritionally vulnerable nations (NVNs), and ask whether aquaculture meets human nutritional demand directly via domestic production or trade, or indirectly via purchase of nutritionally rich dietary substitutes. We find that a limited number of NVNs have domestically farmed seafood, and of those, only specific aquaculture approaches (e.g., freshwater) in some locations have the potential to benefit nutritionally vulnerable populations. While assessment of aquaculture's direct contribution via trade is constrained by data limitations, we find that it is unlikely to contribute substantially to human nutrition in vulnerable groups, as most exported aquaculture consists of high-value species for international markets. We also determine that subpopulations who benefit from aquaculture profits are likely not the same subpopulations who are nutritionally vulnerable, and more research is needed to understand the impacts of aquaculture income gains. Finally, we discuss the relationship of aquaculture to existing trends in capture fisheries in NVNs, and suggest strategies to create lasting solutions to nutritional security, without exacerbating existing challenges in access to food and land resources.

As a result of the concern and debate about the impacts of intensive aquaculture development on biodiversity, semi-intensive aquaculture is being considered as an alternative. Although the biophysical impacts of aquaculture on biodiversity have been examined, there is only limited understanding of the social and economic impacts of aquaculture on biodiversity, and especially the impacts of the shift from intensive to semi-intensive systems. The purposes of this article are twofold: (1) to identify and discuss the social and economic impacts of aquaculture on biodiversity, and (2) to examine the impacts while moving from intensive to semi-intensive systems. After discussing the findings of our study, we provide some recommendations as to how to minimize social and economic impacts of aquaculture on biodiversity by moving to a lower intensity aquaculture system. The integrated agriculture-aquaculture farming systems, stakeholder involvement in management, and well defined basic rights are aquaculture system...

Catfish market research is important in terms of the viability and sustainability of the catfish aquaculture industry in the U.S. Analysis of market trends, retail level price and sales volume have particular importance in the context of the industry's efforts to promote and market their products. Using retail level scanner data, this study examined the market trends of different catfish product forms. The study also investigated the factors affecting prices and sales for frozen catfish products. The present study is a pioneer in using market/city level retail scanner data to study marketing behavior of catfish products under different product categories (i.e., breaded, unbreaded and entrees). The results of the study highlight a need for a non-price competition strategy for catfish retail market. This includes several activities that attempt to provide added value or incentives to consumers, wholesalers, retailers, or other organizational customers to stimulate immediate sales.

Ongoing climate change and anthropogenic activities are introducing stressors that affect the structure and function of coastal ecosystems. This paper focuses on the fluvial fluxes and estuarine transport of nutrients from a tropical river (Mahanadi River) in Northeastern India and compares select nutrient and water quality parameters between 1983 and 2008. This estuary acts as a perennial source of CO2 with a net annual flux to the atmosphere of about 135 tons. The non-conservative fluxes showed a net annual removal of 650 and 140 tons of phosphorus and nitrogen from the water column, respectively. Negative biogeochemical feedbacks that decreased the availability of N and P in 2008 relative to 1983 levels indicate major changes in biogeochemical responses towards fluvial fluxes of nutrient.

Using ‘Constant Market Share’ analysis, we have decomposed the growth of catfish exports of major catfish exporting countries to the United States (U.S.) into structural, competitive and second-order effects and their sub-components. We have also studied competitiveness of the U.S. farm-raised catfish in the domestic market. The U.S. farm-raised catfish industry could not harvest the benefits of the supply-demand gap created in the U.S. due the shift of Vietnam's catfish exports away from the U.S. after 2003; however, China and Thailand and also some other catfish exporting countries derived the greatest extent of the benefits. Decline in the competitiveness of Vietnam's catfish exports to the United States has made China and Thailand catfish more competitive in the U.S. market. The benefits of increased demand for total fisheries products at the world level to the U.S. catfish industry have been marginalized by decline in competitiveness of the U.S. farm-raised catfish in domestic market.

Catfish farmers in the United States (U.S.) are facing reduced market share, falling prices and reduced profitability for their farm-raised catfish, and these problems have been compounded by dramatic increases in global supply of catfish, basa and tra. The objective of this article is to study the growth and determinants of catfish, basa and tra imports to the United States from Vietnam, China and Thailand. The study has applied an augmented gravity model of international trade for this purpose. The results reveal that U.S. imports from Vietnam are significantly affected by variables like: price of the U.S. farm-raised catfish, population of Vietnam, population of the U.S., per-capita gross domestic product (GDP) of Vietnam, freight index, tariff, generic advertisement expenditure of the Catfish Institute (TCI), and country of origin and catfish labeling. Catfish, basa and tra imports from China are affected by population of the United States, per-capita GDP of China, and country of origin and catfish la...

In spite of the long history of tilapia, introduced to Bangladesh in 1954, its culture has yet to become well established because of socioeconomic, technological, institutional, and marketing constraints. Nevertheless, a considerable number of farmers are involved in tilapia farming in the Mymensingh area of north-central Bangladesh. Almost all the tilapias produced are marketed internally for domestic consumption. The marketing chain from farmers to consumers encompasses primary, wholesale, and retail markets. Although the tilapia marketing system is traditional, it plays a vital role in connecting producers with consumers and thus contributes significantly in the value-adding process. Evidence from this study suggests that tilapia marketing could play a greater role in increasing food supply. However, sustainable development of tilapia marketing is essential, if tilapia is to become a more important component of food supplies in the country.

The WorldFish Center and its research partners have recently made efforts to develop genetically improved carp strains. This paper analyses the comparative performance of the genetically improved carp strains on both average and efficient farms in four carp-dominating Asian countries (Bangladesh, India, Thailand and Vietnam). The results show superior performance of improved strains in terms of body weight and survival rate on both average and efficient farms. On an average farm, the improved carp strain gives 15% higher body weight at harvest in India to 36% higher in Bangladesh. On an efficient farm also, the improved carp strain gives similar higher body weight at harvest. The improved carp strain has a higher survival rate on average farms, ranging from 7% in Thailand to about 27% in India. A higher carp yield is predicted for improved strains as compared to local strains under average as well as efficient farms. Genetically improved carp strains are generally neutral to feed use, and can be reared wi...

This paper describes the application of the methodology called Rapid Appraisal of Fisheries Management System (RAFMS) to assess quickly the situation in tsunami-affected coastal fisheries in Aceh Province, Indonesia. As a diagnostic tool, the RAFMS is introduced in terms of its conceptual framework and procedures. The RAFMS was used to appraise the status of the fisheries sector in selected 15 villages. Information generated concerning level of fishing effort, marketing patterns and community perspectives on livelihood options are used as three illustrative examples. The paper also provides some insights in applying the RAFMS methodology in the context of disasters and in the broader context of tropical fisheries management.

Inter-annual variations of phytoplankton abundance and community organization were observed over a two-decade period along with the ancillary parameters at the land–ocean boundary associated with the Sundarban mangrove forest (21°32′ and 22°40′ N and 88°05′ and 89° E), along the NE Coast of the Bay of Bengal. The number of definable Bacillariophyceae species exceeded Dinophyceae taxa, and the total number of bloom-forming species declined from a maximum of ten in 2000 and a minimum of two in 2007. Blooms of the diatom Coscinodiscus radiatus were common in 2000 and 2007. Tide cycles and the onset of the monsoon season played important roles in diurnal and seasonal variability of phytoplankton. Phytoplankton biovolume showed seasonality, with the highest levels during post-monsoon periods and lowest levels during the monsoon period. Phytoplankton abundance was correlated to rainfall patterns, which may be altered by long-term changes in climate.

Applications of a rapid appraisal approach to identify locally available feed ingredients in feed formulation, production, and socio-economics of Nile tilapia aquaculture in Bangladesh are discussed. Three diets of 35%, 30%, and 25% crude protein were formulated using locally available ingredients, and their essential amino acid profiles were assessed for Nile tilapia. Six production scenarios were constructed using these diets and two culture periods of 100 and 150 days were considered. The production scenarios with 35% protein yielded the highest productivity and profitability over the 150-day culture period followed by the 30% protein scenario. Identification of locally available ingredients and their application in small-scale Nile tilapia aquaculture may lead to: (1) increased availability of inexpensive sources of fish production for poor people; (2) increased fish consumption; (3) increased self employment and involvement of women in productive activities; and (4) increased household income to redu...

During the rainy season in extensive river floodplains and deltaic lowlands, floods lasting several months render the land unavailable for crop production for several months each year. These waters...

The research documented in this article estimates the levels and determinants of farm-level technical efficiencies (TE) in freshwater pond polyculture systems in China, India, Thailand, and Vietnam. The levels of country-specific TE were estimated for different production intensity levels by estimating stochastic production frontier functions involving the model for technical inefficiency effects. The results were compared with estimates from past studies of aquaculture TE. It was found that yield, input levels, and TE increases in line with intensity levels. TE estimates ranged from 42% among extensive farms in Vietnam to 93% among intensive farms in China. For low intensity farms, increased technical efficiency, and the resulting increased productivity, could be achieved by increasing human capital (through effective and efficient training and extension), provision of basic infrastructure (such as roads), easier access to seed supplies, and security of tenure or a well-defined system of land us...

Quantitative modeling of fish supply, demand and trade is a useful tool for analyzing recent structural changes, such as the rapid development of aquaculture. Existing models are, however, limited by their use of highly aggregated fish categories and assumed (rather than estimated) elasticities. This paper outlines an estimation strategy and a multiproduct equilibrium model for disaggregated analysis of fish supply, demand, and trade. The model is composed of a producer, consumer and trade core, and is specified to accommodate special features of the fish sector. The estimation and modeling strategy also address common data problems, such as heterogeneity of fish types, diversity of production categories, and so forth. The model has been applied to nine major fish producers in developing Asia.

Tolerance of three strains (GIFT, Sudan 78, Egypt 88) of Nile tilapia, Oreochromis niloticus , to naturally decreasing temperature was evaluated and determined in the Shanghai area. GIFT had been selected for increased body weight. Nile tilapia began to die when the water temperature dropped to 11 °C, and 100% mortality had occurred by 7.4 °C. Low lethal temperature ranged from 11 to 8.4 °C for the GIFT strain, from 9.8 to 7.4 °C for the Sudan 78 strain and from 11 to 7.4 °C for the Egypt 88 strain. The LD 50 for low temperature among the three strains suggested that the GIFT line was less tolerant to low temperature than the other two strains and that there was no difference with respect to temperature tolerance between the Sudan 78 and the Egypt 88 strains. This has important implications for the application of genetically enhanced tilapia in cold climates when developed in warmer regions.

This paper reports stock improvement of silver barb (Barbodes gonionotus Bleeker) using selective breeding techniques and presents the results of three generations of growth performance between selected and nonselected control groups. The breeding program was initiated using two wild caught populations from Thailand and Indonesia and an existing local stock from Bangladesh. To produce the parental base population in 1996, the three unrelated founder stocks were mated through a complete 3×3 diallele crossing experiment to produce nine heterogeneous, outbred genetic groups. In 1997, the first generation (F1) trials were made. For each of the six reciprocal crosses, five to eight pairs were mated separately and the best three progeny groups were selected on the basis of egg fertilization rate, lack of deformities, healthy movement, and survival to make 18 full sib progeny lines. These were then communally stocked by mixing equal numbers of larvae from each family and grown until maturity in ponds. During the spawning season of 1998, the heaviest 20% of mature females and males were mass selected from the F1 communal crossbred group and mated to produce the F2 generation. In 1999, mass selection was again performed, selecting 15% of the best mature breeders from the F2 generation to produce the third generation (F3) for trials. In each generation, evaluation of growth performance was carried out through comparative trials between selected and nonselected control (existing stock of Bangladesh, B×B) groups. A 7.5% genetic gain in growth performance was attained by the F1 crossbred group over the nonselected control group. The F2 and F3 selected groups attained 2.3% and 12.1% cumulative weight gain, respectively, over two generations. The average gain per generation across two generations of selection for growth performance in weight was estimated as 7.2%. The weight gain values of the third generation of the selected group showed 21.9% superiority over the nonselected control. Present findings suggest that the method for improvement of silver barb through several generations of genetic selection might be a useful technique for other carp species in Bangladesh and elsewhere in Asia.

An assessment of the status of production and consumption of tilapia in five Asian countries was made to provide a baseline for the analysis of the potential benefits of the introduction of a new, improved strain of Nile tilapia. This paper provides a comparative analysis of the profile of tilapia fanners and their farming systems, costs, returns and productivity of tilapia production, and fish consumption patterns in Bangladesh, China, the Philippines, Thailand and Vietnam, using data from household surveys conducted by ICLARM and its partners in 1995–96. Farmers grow tilapia in varied farming environments depending on the nature of their farmland and on their investment capacity. Tilapia is cultured mainly in semi‐intensive systems on small and medium farms. The average farm size (pond area) of the surveyed pond operators varies from 0.60 ha (0.05 ha) in Bangladesh to 4.91 ha (1.56 ha) in the Philippines. In Asia, tilapia farming is very profitable. The productivity, costs of production and pro...

An analysis of fish consumption patterns, and how they are likely to change as income and relative price changes, is required to assess the welfare impact of technological and policy changes in the fisheries and aquaculture sectors. This analysis is based on a matrix of price and income elasticities of demand for fish by type, as fish is a heterogeneous product and consumption patterns may differ by type of product. This paper presents estimates of fish demand elasticities by fish type for Bangladesh, using individual household expenditure data (5,667 households) collected by the Bangladesh Bureau of Statistics in 1988/89. It uses a multistage budgeting framework that estimates a demand function for food in the first stage, a demand function for fish (as a group) in the second stage and a set of demand functions for fish by type in the third stage. Estimated demand elasticities vary across fish type and across income class. Among the various types of fish, carp have the highest (in absolute terms...

The determination of efficient production levels for tilapia growout operations, given the existing technology, is necessary to examine alternative options to increase productivity. If fanners are not making efficient use of existing technologies, improving their efficiency is usually more cost‐effective than introducing new technology. This paper examines the technical efficiency of tilapia growout operations in ponds in the Philippines. A stochastic production frontier with technical inefficiency effects model is specified and estimated. The estimated mean technical efficiency of the 78 farmers in the sample is 83%. Total farm area, education and age of the farmers are some of the factors affecting technical efficiency. Those with a larger farm area, higher age and a higher educational level attain higher technical efficiency. As growers in the Philippines have attained a high level of technical efficiency under existing technology, the introduction of new technology is a key to raising the pro...

The International Center for Living Aquatic Resources Management (ICLARM), in collaboration with its partner organizations, has developed an improved strain of Nile tilapia (known as the GIFT strain) which shows superior performance in terms of growth and survival in on‐station conditions. The on‐station performance of the GIFT strain may, however, not be replicated in actual farm conditions. Before disseminating the GIFT strain, its performance and nature were evaluated in on‐farm conditions relative to the strains already being cultivated. This paper analyses the comparative performance of the GIFT strain on an average as well as on an efficient farm and assesses its nature in five Asian countries (i.e., Bangladesh, China, the Philippines, Thailand and Vietnam). Ordinary least squares regression and tobit models are estimated on the average weight at harvest and on the survival rate, respectively, to assess the comparative performance of the GIFT strain on an average farm. Stochastic frontier f...

The International Center for Living Aquatic Resources Management (ICLARM) and its research partners have recently developed a genetically improved Nile tilapia strain. This paper analyzes the potential impact of culturing the improved tilapia strain in five Asian countries (Bangladesh, China, the Philippines, Thailand and Vietnam), using a three‐step procedure. The steps are (1) to develop a model of the fish sector for each country using data from baseline surveys of producers and consumers and from secondary sources, (2) to construct ex ante impact indicators using data collected in on‐farm production trials, and (3) to analyze the impact of the use of the genetically improved Nile tilapia by incorporating the results of on‐farm trials into the fish sector model. The analysis indicates that the use of the genetically improved strain will benefit both producers and consumers offish.

With the recent availability of genetically improved Nile tilapia strain in the Philippines, it is important to look at the existing profile of tilapia hatchery operations in the country to help examine the potential strategies in the dissemination of the improved strain among hatchery operators. This paper attempts to analyze the socioeconomics and production efficiency status of tilapia hatcheries in the Philippines prior to the adoption of genetically improved Nile tilapia strain. A stochastic frontier production function is specified and estimated to examine the levels of farm‐specific technical efficiencies of tilapia hatchery operation. Tilapia hatchery operators in the Philippines have the necessary education, tenure security, and adequate years of experience and are willing to adopt new technologies and better strains if these are made available to them. Tilapia hatchery is a highly profitable operation. The cost of production per unit of fingerling produced will be higher for the genetic...

Seinability of four strains of Nile tilapia, Oreochromis niloticus, was studied in earthen ponds in Huzhou, Zhejiang Province in China during 1995 and 1996. The accumulated seinability of the GIFT, Egypt 88, Sudan 78 and Egypt 92 strains was compared based on three trawls. Seinability of the GIFT strain was higher (P

[1] Biosphere-atmosphere exchange of NOx at the Sundarban mangrove forest along the northeast coast of the Bay of Bengal, India, showed uptake rates of −0.84 to −1.63 ng N m−2 s−1 during the day and both uptake and emission rates of −0.36 to 5.19 ng N m−2 s−1 during the night from September to February. However, during the period from March to August, NOx emission ranged between 0.34 and 2.13 ng N m−2 s−1 and 0.88 and 3.26 ng N m−2 s−1 in daytime and nighttime, respectively. During the postmonsoon period, NOx uptake could be attributed to mangrove stomatal activity during the day. Mangroves absorbed nitrogen from both the soil and the atmosphere. Seasonal and diurnal variability of NOx and O3 is partly due to plant growth in the postmonsoon period. In addition to the NOx-O3 photochemical cycle, stomatal uptake of NOx could also be an important process for keeping a low-ozone state at the land-ocean boundary of the northeast coast of the Bay of Bengal.

This study aims to investigate the control of arsenic distribution by biogeochemical processes in the Indian Sundarban mangrove ecosystem and the importance of this ecosystem as an arsenic source for surrounding coastal water. The As(V)/As(III) ratio was found to be significantly lower in both surface and pore waters compared to sea water, which could be attributed to biogeochemical interconversion of these arsenic forms. The biological uptake of arsenic due to primary and benthic production occurs during the post-monsoon season, and is followed by the release of arsenic during the biochemical degradation and dissolution of plankton in the pre-monsoon season. These results suggest that arsenic is immobilized during incorporation into the arsenic-bearing initial phase, and unlikely to be released into pore water until the complete microbial degradation of arsenic-bearing organic compounds.