Economic incentives drive the conversion of agriculture to aquaculture in the Indian Sundarbans: Livelihood and environmental implications of different aquaculture types.

Expansion of aquaculture in the Sundarbans Biosphere Reserve (SBR) is irreversibly replacing agricultural land and the drivers of this change are disputed. Based on in-depth interviews with 67 aquaculture farmers, this paper characterizes major aquaculture types in the SBR, their impacts, and identifies drivers of conversion from agricultural land. Aquaculture types included traditional, improved-traditional, modified-extensive, and semi-intensive systems. Extensive capture of wild shrimp larvae is environmentally harmful but constitutes an important livelihood. Semi-intensive aquaculture of exotic shrimp (Litopenaeus vannamei) has much higher unit-area profitability than other types but involves greater financial risk. Profitability is the main driver for the transition from agriculture, but environmental factors such as lowered crop yields and cyclone impacts also contributed. Many conversions from agriculture to aquaculture are illegal according to the stakeholders. Existing legislation, if enforced, could halt the loss of agriculture, while the promotion of improved-traditional aquaculture could reduce the demand for wild seed.

Improving mariculture insurance premium rate calculation using an information diffusion model.

Mariculture is a well-known high-risk industry. However, mariculture insurance, which is an important risk management tool, is facing serious market failure. An important reason for this market failure lies in the unsound premium rate and pricing method. Due to a lack of long-term yield data, empirical rates are often adopted, but this adoption can lead to a high loss ratio. This paper provides an improved method for premium computation of mariculture insurance using an information diffusion model (IDM). An example of oyster insurance in China shows that, compared with the traditional pricing approach, the IDM can greatly improve the accuracy and stability of premium rate calculations, especially in cases of small samples.

Analysis on the structure effect of marine fishery total factor productivity under high-quality development in China.

Improving total factor productivity (TFP) is the source of power for high-quality development. Industrial structure optimization is an important way to improve TFP. This paper constructed an econometric model of industry structure changes impacting on TFP in the marine fisheries and conducted an empirical test and analysis. The results showed that the industry rationalization, softening and processing coefficient of marine fishery had a significant "structural dividend" for improving its TFP; while the impact of industrial structure advancement and aquaculture-catching structure changes did not have "structural dividend", but it could be a combination of other factors to reduce these adverse effects.We believe that simply pursuing the advanced evolution of the industrial structure is not conducive to sustainable development of fishery. Under the pursuit of the rationalization of the marine fishery industry structure, by promoting the coordinated evolution of marine fisheries advancement, aquaculture-catching structure and other factors, the "structural dividend" effect can be enhanced and the fishery can achieve sustainable development. Finally, it proposed to promote the development of advancement and rationalization of marine fishery industry structure coordinately, adjust fishery science and technology transformation direction and key points, and accelerate the development of intensive processing industry by cross-border integration.

Phenotypic and Genetic Characterization of Flavobacterium psychrophilum Recovered from Diseased Salmonids in China.

Flavobacterium psychrophilum, the etiological agent of bacterial coldwater disease (BCWD) and rainbow trout fry syndrome, causes great economic losses in salmonid aquaculture worldwide. Recent molecular studies have uncovered important epidemiological and ecological aspects of this pathogen; however, such data are lacking for F. psychrophilum populations affecting aquaculture in China. Herein, F. psychrophilum phenotype, genotype, and virulence were characterized for isolates recovered from epizootics in multiple salmonid aquaculture facilities across China. Thirty-one F. psychrophilum isolates, originating from four provinces and three host fish species, were predominantly homogeneous biochemically but represented 5 sequence types (STs) according to multilocus sequence typing (MLST) that belonged to clonal complex CC-ST10 or 3 newly recognized singleton STs. PCR-based serotyping classified 19 and 12 F. psychrophilum isolates into molecular serotypes 1 and 0, respectively, showing an obvious relationship with host species. Antimicrobial susceptibility analysis via broth microdilution revealed reduced susceptibility to enrofloxacin, flumequine, and oxolinic acid, moderate susceptibility to gentamicin, erythromycin, and florfenicol, and variable susceptibility to ampicillin and oxytetracycline. In vivo challenge experiments confirmed the ability of two representative Chinese F. psychrophilum isolates to induce typical signs of BCWD and mortality in 1-year-old rainbow trout (Oncorhynchus mykiss). Findings collectively demonstrate (i) that BCWD outbreaks in China studied thus far are caused by F. psychrophilum lineages that are common on other continents (e.g., CC-ST10) and others that have not been reported elsewhere (e.g., ST355, ST356, ST357), (ii) that F. psychrophilum molecular serotypes distinguish isolates from different host fish species, even within STs, and (iii) reduced F. psychrophilum antimicrobial susceptibility against compounds used for BCWD control in China. IMPORTANCE Flavobacterium psychrophilum causes substantial economic losses in salmonid aquaculture worldwide. Although this bacterium is also believed to be a disease source in China, published reports of its presence do not yet exist. Herein, F. psychrophilum was linked to multiple disease outbreaks in several salmonid aquaculture facilities within four Chinese provinces, and polyphasic characterization revealed that most isolates were genetically distinct from strains recovered on other continents. Analyses further revealed the predominating molecular serotypes, antimicrobial susceptibility profiles, and pathogenic potential of two representative recovered isolates. Collectively, the results presented here provide important data on the epidemiology and disease ecology of F. psychrophilum in China and pave the way for targeted prevention and control methods to be pursued in the future.

Growth performance, hematological responses and economic indexes of Colossoma macropomum (Cuvier, 1818) fed graded levels of glycerol.

The aim of this study was to evaluate the performance, hematological responses and economic indicators of juvenile tambaqui Colossoma macropomum fed different levels of partial replacement of corn by glycerol (0%, 25%, 50%, 75%, and 100%). The experiment was conducted for 90 days in the production of aquatic organisms lab at the Nilton Lins University, Manaus, Brazil, in a completely randomized design, and consisted of four treatments, four repetitions and two sampling times. In total, 240 juveniles were used with initial average weight and standard length of 15.32 ± 1,61 g and 8.03 ± 0.22 cm, respectively. The fish were maintained in twenty 310 L water tanks that had a closed system with no reuse, continuous aeration, siphoning and replacement of water every 48 h. Feeding was twice a day with the experimental diets, which contained 28% crude protein. The following parameters were considered: zootechnical checks (weight gain + survival %), welfare (health) (hepatosomatic index + condition factor + viscerosomatic index), economic (Economic efficiency rate + economic profitability index) and hematology (hematology + metabolites + ions). The results of the study show that diets for juvenile tambaqui can contain up to 50% replacement of corn by glycerol without compromising the fishes' development under the conditions studied.

Replacing fish meal with rapeseed meal: potential impact on the growth performance, profitability measures, serum biomarkers, antioxidant status, intestinal morphometric analysis, and water quality of Oreochromis niloticus and Sarotherodon galilaeus fingerlings.

The aim of this study was to assess the impact of using rapeseed meal as a partial replacement for fish meal in the diet of farmed tilapia. We evaluated the effect of this replacement on growth performance, profitability, serum biomarkers, antioxidant status, gut morphology, and water quality. A total of 960 apparently healthy Oreochromis niloticus (O. niloticus) and Sarotherodon galilaeus (S. galilaeus) fingerlings were randomly distributed into four dietary treatment groups for each tilapia species (triplicate design, 120 fish/group, and 40 fish/replicate). The diets consumed by these groups were formulated to replace fish meal (FM) with rapeseed meal (RM) at 0%, 10%, 20%, and 30%, respectively, for 12 consecutive weeks. Results indicated that replacing RM in the diet of S. galilaeus (up to 20%) and O. niloticus (up to 10%) resulted in increased growth performance parameters, including final weight, weight gain, length, length gain, weight gain rate, and specific growth rate (SGR), and return parameters such as a total return and relative return compared to the control group. Moreover, an increase in RM up to 30% improved net profit and increased the mucosal length, intestinal villi length, and the number of goblet cells compared with results in its relative control groups. Additionally, we observed a significant increase in serum and liver AST and ALT with increased RM replacement. With respect to water parameters, we observed a significant difference in the ammonia levels, turbidity, and conductivity with the changes to the percentage of RM in the diets. As for the effect on each species, O. niloticus showed a more significant increase in all examined parameters compared to results in S. galilaeus. In summary, up to 10% RM can be used to replace FM without any adverse effects on the growth performance, profitability measures, intestinal morphometric analysis, or water quality.

Comparative analysis of profitability and resource use efficiency between Penaeus monodon and Litopenaeus vannamei in India.

The study aimed to highlight the profitability and production function analysis of Penaeus monodon and Litopenaeus vannamei in intensified shrimp farms in Gujarat (India). Two hundred and twenty (220) shrimp farm households were used to identify (principal component and cluster analyses) 8 clusters of management practices that reflected various scales of production intensity ranging from 0-2999 kg/ha/crop to 9000kg/ha/crop and above for both the species. The Cobb-Douglas production function, which relates production output to several independent input variables, was used to determine productivity. The budgeting analysis for both the species showed that more intensively managed farms performed more than the less intensive farm. Empirical results show feed as most significant input for Penaeus monodon and Litopenaeus vannamei seed and labor that affected production. Average net returns/ha/year for Penaeus monodon was $16313.13 and for Litopenaeus vannamei $41640.99. Aquaculture exhibited decreasing returns to scale for both the species and estimates on resource use efficiency revealed that in Penaeus monodon the resources were economically utilized and in case of Litopenaeus vannamei the output was likely to increase if more of seed and less of labor would have been used. The major constraint for the shrimp farmers was diseases which can be mitigated by optimum stocking densities and proper feed management.

The economics of shrimp disease.

Shrimp is not only one of the world's most valuable aquaculture species, but also a species that encounter high economic losses due to diseases. Diseases are sufficiently important to influence global supply and prices for longer periods. Profitability is the driving force behind shrimp farming and high profits associated with the absence of disease largely determines where shrimp production does take place; i.e. prevalence of disease leads to geographic relocation. In this paper, a basic economic model for the impact of the disease on a shrimp farm is provided and a Monte Carlo simulation is provided to illustrate the impact of disease on economic risk. Improved technologies, knowledge, and governance are important elements utilized in the mitigation of diseases in various shrimp producing countries. Economic aspects such as profitability in the absence and presence of diseases and cost of treatment determines the global production of shrimp along with shaping technologies and production systems.

The transboundary nature of the world's exploited marine species.

Regulatory boundaries and species distributions often do not align. This is especially the case for marine species crossing multiple Exclusive Economic Zones (EEZs). Such movements represent a challenge for fisheries management, as policies tend to focus at the national level, yet international collaborations are needed to maximize long-term ecological, social and economic benefits of shared marine species. Here, we combined species distributions and the spatial delineation of EEZs at the global level to identify the number of commercially exploited marine species that are shared between neighboring nations. We found that 67% of the species analyzed are transboundary (n = 633). Between 2005 and 2014, fisheries targeting these species within global-EEZs caught on average 48 million tonnes per year, equivalent to an average of USD 77 billion in annual fishing revenue. For select countries, over 90% of their catch and economic benefits were attributable to a few shared resources. Our analysis suggests that catches from transboundary species are declining more than those from non-transboundary species. Our study has direct implications for managing fisheries targeting transboundary species, highlighting the need for strengthened effective and equitable international cooperation.

Diet type influences the gut microbiome and nutrient assimilation of Genetically Improved Farmed Tilapia (Oreochromis niloticus).

Nile tilapia, Oreochromis niloticus is the third most commonly farmed finfish species in the world, accounting for nearly 5% of global aquaculture production. In the past few decades much of the success of this species has been attributed to the development and distribution of Genetically Improved Farmed Tilapia (GIFT). Despite the increasing availability of GIFT, the productivity of small-scale farming remains highly variable, particularly in developing nations. Commercial fish-feed pellets can increase fish farm productivity; however, many small-scale farmers rely on other means of feeding fish due to the high cost and limited availability of commercial fish feed pellets. Therefore, understanding how locally-sourced feeds affect the production of GIFT is an important step towards improving feeding practices, particularly for farmers with low financial capital. This study used stable isotope analysis (SIA) and 16S rRNA gene sequencing to compare the effects of a locally-sourced vegetable-based diet and commercial pellet-based diets on the relative condition, nutrient assimilation patterns and gastrointestinal microbiota of GIFT. GIFT fed a locally-sourced diet were smaller, and in a significantly poorer condition than those fed with commercial fish feeds. SIA showed no differences in dietary carbon between the two diets; however, δ13C, poor fish condition and the abundance of specific bacterial taxa (of such as Fusobacteria) were correlated. SIA revealed that GIFT fed locally-sourced diets that predominantly consisted of vegetables were significantly enriched in δ15N despite a perceived lack of dietary protein. This enrichment suggests that GIFT fed a locally-sourced diet may be supplementing their diet via cannibalism, a behaviour representative of poor farming practice. Overall this study highlights the need to increase the availability of suitable GIFT feeds in developing nations. The development a low-cost feed alternative could improve the success of small-scale GIFT farmers in PNG, increasing both food and income security within the region.

Understanding fish production and marketing systems in North-western Nigeria and identification of potential food safety risks using value chain framework.

Fish production systems in North-western Nigeria have a significant role in food, nutrition and income generations to families, yet an important setup for zoonotic disease transmission. The aim of this study was to provide a broad knowledge of the structure, activities and food safety risks of the fish value chains operating in North-western Nigeria using the value chain framework. A total of 16 focus groups and 8 key informant interviews were conducted to gather data from fish producers, fish sellers and fish processors in selected peri-urban and rural settlements in Kaduna State. In addition, 129 semi-structured questionnaires and observation checklists were used in this study to gather evidence-based data, such as demography of value chain actors, product characterization, and food safety risks. The fish value-chain in North-western Nigeria is characterised by four main stakeholders, namely, fish producers, transporters, as well as raw- and processed-fish-sellers (wholesalers, retailers). Two major sources were identified supplying farmed fish to North-western Nigeria: the distributors from the central and southern part of the country and the fish farmers within the North-western and North-eastern regions of Nigeria. Raw-fish-wholesalers within the two major markets sold most of their high-value products to raw-fish-retailers, while low-value products were routed to raw-fish-retailers in the rural communities, processed-fish-retailers and household consumers in rural settlements. There were no large companies operating and no differentiation of chains between aquaculture and wild fishery. Raw fishes not sold and began to rot were sold to street vendors at a cheaper price and household consumers. Fish production and supply chains were characterised by poor structural and sanitary support for food safety and hygiene measures. Food safety risks identified were related to lack of biosecurity measures in fish farms, lack of cold chain and access to running water, poor hygiene practices by all handlers, lack of fish inspection at all levels, lack of use of protective clothing and limited health inspection of handlers. In overall, government control of activities in fish value chains was relatively poor leading to the absence of food safety regulatory enforcement characterised by lack of institutional goals on improving food safety measures in a chain-wide distribution. Hence, this study points the significant structural, sanitary and hygiene limitations along the fish value chain components. It provides a baseline for microbial food safety risk assessments, and information required for policy-making regarding implementation of disease control programmes, as the sector is fast-evolving in Sub-Saharan Africa.

Legal regulations and consumer attitudes regarding the use of products obtained from aquaculture.

Aquaculture is an industrial activity that not only aims to be a source of quality food, but also is a way to restock fish populations and to conserve the biodiversity of our oceans. On the other hand, the production system can influence the consumer perceptions about what is purchased and consumed, as well as the subsequent environmental and social effects. Fish feeding production is affected by the growth of aquaculture and the increasing demand that have let to deficit, high prices, and low ecological safety of fish meal and oil. In this regard, the use of microbial biomass obtained from a variety of microorganisms has been reported as a potential substitute for plant- and animal-derived ingredients, satisfying the requirements in protein and energy and even adding functional properties. In addition, microalgae can increase the nutritional value of animal feed, play a key role in the physiological growth and external appearance of aquatic animals. Finally, politicians, industry and society in general should be careful with the numerous uncertainties still present in the sector that can weaken its sustainability from environmental, social and economic perspectives.

Addressing distribution equity in spatial conservation prioritization for small-scale fisheries.

Spatial conservation prioritization is used worldwide for designing marine protected areas (MPA) that achieve set conservation objectives with minimal impacts to marine users. People involved in small-scale fisheries (SSF) may incur negative and disproportionate impacts from implementing MPAs, yet limited available data often restricts their representation in MPA planning. Using a Philippines case study, we focus here on the systematic design of a MPA network that aims to minimize and distribute costs equitably for SSF whilst achieving representation targets for biodiversity conservation. The objectives of the study are to: (1) document a participatory mapping approach for collecting SSF data for prioritization using the local knowledge of fishers; and (2) examine how the completeness and resolution of SSF data may affect prioritization outputs in terms of biodiversity representation, spatial efficiency, and distribution equity. In the data-poor region, we conducted participatory mapping workshops with fishers in 79 communities to collect data on the spatial distribution patterns of different SSF fisheries and communities, and employed remote sensing techniques to define coastal habitats, which were targeted for inclusion in MPAs. The datasets were integrated within the decision-support tool Marxan with Zones to develop three scenarios. The SSF data incorporated in each scenario varied based on their completeness (considered all fishing methods or only dominant methods) and resolution (fishing methods itemized by community or municipality). All scenarios derived MPA plans that met representation targets with similar area coverage. The outputs, however, varied in terms of distribution equity, measured by the distribution of opportunity costs (loss of fishing grounds) across different fisheries and communities. Scenarios that did not include minority fisheries or variations between communities, led to inequitable costs. These results highlight the need to incorporate detailed data on SSF at appropriate resolutions, and how this can be achieved through participatory approaches.

Perceived socio-economic impacts of the marbled crayfish invasion in Madagascar.

The negative environmental and economic impacts of many invasive species are well known. However, given the increased homogenization of global biota, and the difficulty of eradicating species once established, a balanced approach to considering the impacts of invasive species is needed. The marbled crayfish (Procambarus virginalis) is a parthenogenetic freshwater crayfish that was first observed in Madagascar around 2005 and has spread rapidly. We present the results of a socio-economic survey (n = 385) in three regions of Madagascar that vary in terms of when the marbled crayfish first arrived. Respondents generally considered marbled crayfish to have a negative impact on rice agriculture and fishing, however the animals were seen as making a positive contribution to household economy and food security. Regression modeling showed that respondents in regions with longer experience of marbled crayfish have more positive perceptions. Unsurprisingly, considering the perception that crayfish negatively impact rice agriculture, those not involved in crayfish harvesting and trading had more negative views towards the crayfish than those involved in crayfish-related activities. Food preference ranking and market surveys revealed the acceptance of marbled crayfish as a cheap source of animal protein; a clear positive in a country with widespread malnutrition. While data on biodiversity impacts of the marbled crayfish invasion in Madagascar are still completely lacking, this study provides insight into the socio-economic impacts of the dramatic spread of this unique invasive species. "Biby kely tsy fantam-piaviana, mahavelona fianakaviana" (a small animal coming from who knows where which supports the needs of the family). Government worker Analamanga, Madagascar.

The genetic correlation between feed conversion ratio and growth rate affects the design of a breeding program for more sustainable fish production.

BACKGROUND: Most fish breeding programs aim at improving growth rate and include feed conversion ratio (FCR) neither in the breeding goal nor in the selection index, although decreasing FCR is known to increase farm profit and decrease environmental impacts. This is because FCR is difficult to measure in fish that live in groups and FCR is assumed to have a favourable (negative) genetic correlation with growth, although the magnitude of this correlation is unknown. We investigated the effect of the genetic correlation between growth and FCR on the economic and environmental responses of a two-trait breeding goal (growth and FCR), compared to a single-trait breeding goal (growth only). Next, we evaluated the weights to assign to growth and FCR in a two-trait breeding goal to maximize sustainability of fish production. METHODS: We used pseudo-best linear unbiased prediction (BLUP) index calculations to simulate a breeding program for sea bass. For the single-trait breeding goal, the trait in the breeding goal and in the index was thermal growth coefficient (TGC) and for the two-trait breeding goal, the traits in the breeding goal were TGC and FCR and the traits in the index were TGC and percentage of fat in the dorsal muscle (an indirect measure of FCR). We simulated responses to selection for genetic and phenotypic correlations between TGC and FCR ranging from 0 to - 0.8. Then, in the two-trait breeding goal, we calculated the economic return and the change in eutrophication when using economic values (EV) or environmental values (ENV). RESULTS: When the genetic correlation between TGC and FCR was lower than - 0.45, we found major differences in economic returns and in eutrophication between single and two-trait breeding programs. At a correlation of - 0.25, the two-trait breeding goal based on EV increased economic return by 25% compared to the single-trait breeding goal, while using ENV decreased eutrophication by 1.34% per ton of fish produced after one generation of selection. CONCLUSIONS: The genetic correlation between TGC and FCR affects the magnitude of economic losses due to omitting FCR in the breeding program. In addition, the genetic correlation affects the importance of choosing EV or ENV to reduce eutrophication and increase profit.

A capability approach to assess aquaculture sustainability standard compliance.

Sustainability standards are used to assure improved environmental performance in the aquaculture sector. But standard setters face limitations in including a broad range of producers with different capabilities, which in turn reduces their scope and impact. Drawing on Sen's capability approach, we introduce a novel way to assess the extent to which sustainability standards can support the capability of farmers to make prescribed improvements to their production practices. In doing so, we compare four shrimp aquaculture standards (Aquaculture Stewardship Council, Global Aquaculture Alliance, Southeast Asian Shrimp Aquaculture Improvement Protocol and the Thai Agricultural Standard) based on an analysis of what we label the 'prescribed capitals' and 'bundle of capitals' that underpin the compliance capability of producers. The results show that standards narrowly prescribe standards requiring human capital, while there is potential for prescribing a wider bundle of social, financial and physical capitals that can allow more flexible standard compliance. The findings raise the prospect of redesigning sustainability standards to support a broader diversity of producer capabilities and, in turn, increase their overall impact.

Marine seafood production via intense exploitation and cultivation in China: Costs, benefits, and risks.

Identifying strategies to maintain seafood supply is central to global food supply. China is the world's largest producer of seafood and has used a variety of production methods in the ocean including domestic capture fisheries, aquaculture (both freshwater and marine), stock enhancement, artificial reef building, and distant water fisheries. Here we survey the outcomes of China's marine seafood production strategies, with particular attention paid to the associated costs, benefits, and risks. Benefits identified include high production, low management costs, and high employment, but significant costs and risks were also identified. For example, a majority of fish in China's catches are one year-old, ecosystem and catch composition has changed relative to the past, wild and farmed stocks can interact both negatively and positively, distant water fisheries are a potential source of conflict, and disease has caused crashes in mariculture farms. Reforming China's wild capture fisheries management toward strategies used by developed nations would continue to shift the burden of production to aquaculture and could have negative social impacts due to differences in fishing fleet size and behavior, ecosystem structure, and markets. Consequently, China may need to develop novel management methods in reform efforts, rather than rely on examples from other large seafood producing countries. Improved accounting of production from fisheries and aquaculture, harmonization and centralization of historical data sets and systematic scientific surveys would improve the knowledge base for planning and evaluating future reform.

Measuring the impacts of aquatic animal diseases: the role of economic analysis.

Aquaculture is an important industry both economically and socially. The majority of this industry is focused on the production of aquatic animals, which may be substantially adversely affected by disease. Economic analyses may be used to inform decision-makers on the aquatic animal disease control choices that are economically optimal. Examples of such analyses are presented in this paper, ranging from basic cost estimates of disease impact to complex, spatial- temporal, bio-economic models. Regardless of the complexity of the analysis, there is a consistent need to collect and analyse good quality data measuring both the production and health of aquatic animals. This would require a variety of individuals and groups, including farmers, scientists and the government, to collaboratively contribute to this end. Given the necessary data, more sophisticated models may be better used to inform decision-making from the farm to the national level. Finally, economic analyses should not be limited to simple aggregated cost and benefit results but rather should include the social and gender impacts of financial decisions, as well as the potential externalities both within and among the various impacted sectors in order to optimise investment at both the farm and national levels.

Le secteur de l'aquaculture joue un rôle important aux plans tant économique que social. La majorité des filières du secteur sont axées sur la production d'animaux aquatiques, espèces susceptibles à des maladies à l'impact souvent considérable. Les décideurs ont la possibilité de recourir à des analyses économiques afin de sélectionner les stratégies de lutte contre les maladies des animaux aquatiques optimales au plan économique. L'auteur présente quelques exemples de ce type d'analyses, qui vont de l'estimation basique des coûts liés à l'impact d'une maladie à des modèles analytiques complexes, spatiotemporels et bioéconomiques. Indépendamment de la complexité de l'analyse, il est à chaque fois indispensable de collecter et d'analyser des données de bonne qualité concernant la production et la santé des animaux aquatiques. La réussite d'une telle entreprise nécessite la contribution d'un large éventail d'acteurs individuels et collectifs travaillant en collaboration, dont les éleveurs, les chercheurs et les instances gouvernementales. Dès lors que l'on dispose des données nécessaires, des modèles plus sophistiqués pourront être utilisés afin d'étayer les prises de décision depuis les élevages jusqu'au niveau national. Enfin, les analyses économiques ne devraient pas se limiter à de simples résultats agrégés des coûts et des bénéfices mais devraient prendre en compte les impacts sociaux des décisions financières et leurs répercussions sexospécifiques, ainsi que les effets externes potentiels sur et parmi les divers secteurs affectés, dans le but d'optimiser les investissements réalisés aussi bien au niveau des élevages qu'à l'échelle nationale.

La acuicultura es una actividad industrial importante, a la vez económica y socialmente. El grueso del sector está dedicado a la producción de animales acuáticos, en los que pueden hacer estragos las enfermedades. Los análisis económicos pueden ser utilizados por las instancias decisorias para decidir con conocimiento de causa acerca de las líneas de actuación económicamente idóneas para combatir las enfermedades de dichos animales. El autor presenta ejemplos de este tipo de análisis, que van desde estimaciones básicas del costo de las consecuencias de una enfermedad hasta complejos modelos bioeconómicos que integran la dimensión espaciotemporal. Ahora bien, sea cual sea el nivel de complejidad del análisis, siempre es necesario reunir y analizar datos de buena calidad que midan tanto la producción como el estado de salud de los animales acuáticos. Para hacer posible tal objetivo sería menester que diversas personas y colectividades, entre ellas productores, científicos y administraciones públicas, trabajaran de consuno con este fin. Habida cuenta de los datos necesarios, es posible dar un mejor uso a modelos más sofisticados para fundamentar los procesos decisorios a todos los niveles, desde la explotación hasta el ámbito nacional. Los resultados de los análisis económicos, por último, lejos de ofrecer meras sumas de costos y beneficios, deberían también dar cuenta de los efectos sociales o ligados al género de las decisiones de índole económica, así como de eventuales influencias externas que se dejen sentir en los diversos sectores afectados, o que se ejerzan de uno a otro de esos sectores, con el fin de optimizar las inversiones tanto en cada explotación como a escala nacional.