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The history of the French shellfish industry is marked by a series of overfishing crises occurring in most of the open-access shellfish beds. When the concession system was introduced (1852), it was designed to cope with congestion and overfishing issues more than with the development of shellfish culture. After closing the production cycle in the late 19th century, the oyster industry kept suffering major crises such as massive disease outbreaks. Their occurrence can be analyzed in terms of overexploitation resulting from environmental externalities. We will show that this can create a backward-bending supply curve for oysters, using the Bay of Bourgneuf as a case study. In this bay, 400 firms, mostly family-sized, are being conceded 1,000 ha and sell 10,000 tons of Crassostrea gigas oysters a year. The paper presents a typology of farmers based on a survey that shows that farmer behavior can be aggregated into three main groups. [ABSTRACT FROM AUTHOR]

In Mexico, marine finfish cage culture is envisioned as an economic alternative for coastal fishermen. Because research and outreach have not yet proved that this is profitable, assessing the investment through financial risk assessment and setting reference points for expected outcomes is useful. For Lutjanus guttatus, this research reports on a 10-year investment analysis of a pilot-scale, ongrowing four-cage module tested in Mazatlán, Mexico that incorporated a) hatchery-reared fry, b) species-specific feed and c) a second-generation prototype cage, all of them results of almost a decade of research. Two production scenarios were examined: Scenario I, with a high survival rate (90%-95%) and a low feed conversion ratio (FCR) (1.4-1.7), and Scenario II, with a low survival rate (67%-75%) and a high FCR (1.8-2.0). The net present value results are positive for Scenario I (mean = US$134,709, and a 95% probability interval (PI) [US$91,621; US$176,436]) and negative for Scenario II (mean = US-$79,082, 95% PI [US-$116,140; US-$42,054]). To identify feasibility improvement, reference points (threshold values) for survival, FCR, fry and feed costs were determined. [ABSTRACT FROM AUTHOR]

This article presents an analysis of the profitability and intensity of cobia culture by small-scale farmers in Vietnam, especially focusing on current feeding practices and perceptions regarding adoption of manufactured diets. Bioeconomic modelling is used so the interactions between biological and economic processes can be analyzed. Overall, it is found that cobia farming is moderately to highly profitable when compared to other aquaculture species in Vietnam. Culture practices and the level of intensity of cobia farming differ significantly across Vietnam. Initial stocking density, total number of fish stocked, number and size of cages, and quantity of feed used are all higher in southern Vietnam than the north. The higher level of intensification in the south leads to significantly higher total costs, productivity and profitability. The dominant cost source is feed, which is predominantly low-value fish. To capture the environmental and potential economic benefits of adopting pelleted diets, then negative farmer perceptions regarding relatively slow growth rates, and lack of availability compared with low-value fish need to be overcome. [ABSTRACT FROM AUTHOR]

Bioeconomic modeling was used to evaluate traditional and extensive shrimp production in the Mahakam Delta and impacts of adopting Better Management Practices (BMP) for semi-intensive and integrated mangrove-shrimp culture. Modeling outcomes indicate that traditional production is not financially viable, failing to generate a positive 10-year Internal Rate of Return (IRR). Such practices persist in the Mahakam Delta as capital costs have been depreciated against past financial returns, input costs are negligible, risks are minimal, opportunity costs are low and options to intensify production have been retained by producers. Returns from BMP-guided semi-intensive culture (20% IRR) are marginally higher compared to extensive culture but entail a 10-fold increase in operating costs and greater risks. Integrated mangrove-shrimp production gives a reasonable IRR (53%) but costs remain high, management demanding and risks uncertain. Risk adverse operators with short-term leases may favor traditional and extensive practices. Sustainable intensification, allied to social capital development and rehabilitation of mangrove ecosystem services and environmental flows, is needed to reconcile multiple demands. [ABSTRACT FROM AUTHOR]

This study formulates and parameterizes a bioeconomic model of capture-based aquaculture (CBA) of cod (Gadus morhua). The model is solved for the optimal harvest pattern and calculates economic profit and net present value for a model farm. The biological sub-model incorporates knowledge from interviews with existing farmers, research trials and existing cod aquaculture literature. Economic components are obtained from interviews and sales statistics from exporters. A farm of the modeled scale is likely to influence market prices, hence sales prices were estimated assuming a supply response based on the price elasticity. Taking into account the opportunity cost of selling the fish directly, NPV is found to be marginally positive. Sensitivity analysis revealed that profitability is sensitive to changes in several parameters. Hence, further research is valuable and care should be taken when considering investments in cod CBA. [ABSTRACT FROM AUTHOR]

High dissolved CO2 levels in tank water are potentially detrimental to the production and welfare of Atlantic salmon smolts in Norwegian hatcheries. A potential welfare action for reducing CO2 levels is to deploy CO2 stripping technology. The economic consequences of using this approach were modelled using a bio-economic decision analysis tool. Results from the model showed that farmers can improve fish welfare and their profits by utilizing CO2 stripping technology, as costs of implementing the welfare action were less than the potential bio-economic benefits that can be achieved through improved productivity and any potential added value for improving the welfare of smolts. [ABSTRACT FROM AUTHOR]

The aim of this analysis is to conduct bioeconomic analysis of mud crab growout farming in Vietnam and to analyze the cost-effectiveness of potential manufactured feed diets for these farms. Profitability of these farming systems is found to be moderate compared with other seafood growout operations in the country, but return to investment is relatively high. Costs are dominated by seed and labor. Feed and other input costs are low indicating the low input, extensive nature of current mud crab farming systems. It is found that forthcoming pelleted diets are likely to increase a farmer's net revenue by up to 24%, depending on the region. As mud crab farming systems intensify, it is likely that farmers will be increasingly better off with the introduction of pelleted diets, especially if they have the benefit of reducing mortality (through the inclusion of vitamins and other additives). [ABSTRACT FROM AUTHOR]

A bioeconomic model of reservoir aquaculture in northern Vietnam is used to investigate the impacts of fish price and yield variability on the level and riskiness of expected net revenue. Net revenue is volatile compared with similar enterprises in other countries, mainly due to high yield variability. This reflects the nascent nature of the industry in Vietnam and the potential for efficiency and productivity improvements. Increasing production intensiveness, as well as reservoir size, was found to increase profits and decrease revenue risk. Among the management parameters studied, expected net revenue was found to be most sensitive to the length of the production cycle and to the harvest rate, while revenue risk was most sensitive to cycle length. Reservoir size was found to affect net revenue less than anticipated. Although common carp monoculture was found to maximize expected profit, the current species mix minimizes risk, thereby suggesting high risk aversion by northern Vietnam's poor farmers. [ABSTRACT FROM AUTHOR]

This research presents a bioeconomic framework for assessing the economic feasibility of an offshore bluefin tuna aquaculture operation by developing a dynamic stochastic adaptive bioeconomic model of such an offshore enterprise. The bioeconomic model incorporates the biological constraints of the species, the interaction of relevant economic parameters and constraints, and stochastic sources of risk to solve for the profit maximizing behavior of a farmed bluefin tuna producer. The model identifies the optimal harvest schedule for an offshore bluefin tuna farming facility that maximizes the net present value of the operation under a variety of economic, biological and regulatory conditions. Such a model is relevant given the growing prevalence of bluefin tuna farming worldwide, the present lack of studies formally examining the economics of this form of production, and the uncertainty surrounding the economic feasibility and sustainability of this form of production. [ABSTRACT FROM AUTHOR]