Search

Traditional farmers of milkfish and shrimp use 80% of Indonesia's shrimp production area, but produce only 10% of its shrimp. A coastal protection project funded a 16-day aquaculture field school (AFS) in order to train 277 farmers in Low External Input Sustainable Aquaculture (LEISA). Its cost was 1,060 USD per farmer. In 2017 and 2018, the project monitoring database completed records of yields and practices of 125 participants and monitored finances and water quality in a 10% sample. LEISA was adopted by 85% of the 125 participants. The two annual datasets of the sample were merged and trimmed from three outliers; this was done before statistical analysis. Compared to the baseline, LEISA adopters among the 125 tripled their shrimp' yields. Within the sample, the milkfish yields of adopters and non-adopters were about identical. Sampled adopters significantly increased their gross margin by 927 USD ha−1 year−1 due to three- and fivefold yield increases for milkfish and shrimp compared to that of the baseline. The rate of return was 1.3 for the 277 participants and 1.8 for the sample, indicating a payback time of <1 year. Enriching the farmers' skills with AFS can double Indonesian milkfish production and increase its shrimp production by 25–50%.

Purpose: Mekong Delta's shrimp farming contributes to socio-economic development but tends to reduce the mangrove area. On the one hand, NGOs advocate balancing ecology and economy, while on the other hand, the Vietnamese government supports intensifying shrimp production. The latter strategy increases shrimp diseases and marginalises smallholders. To influence the opinions, knowledge and behaviour of shrimp farmers, we developed and tested a serious board game. Approach: Through several iterations, we designed a realistic board game mimicking local shrimp farming. Then, after conducting three sessions of gameplay with farmers in three sites, we assessed how this gameplay influenced players. We used a semi-experimental set-up by collecting data on the day of the gameplay, and on two further time-points. Findings: After the gameplays, farmers reported to have learned about the risks of monoculture-intensive-shrimp system and the advantages of hybrid systems. Likert ratings showed that players adopted innovations faster and, in case of shrimp diseases, consulted commercial service-providers less, but with other farmers more. They confirmed to have learned that the best strategy for them would be to adopt hybrid systems, i.e. intensify part of the area of mixed-mangrove or improved-extensive shrimp farms. Theoretical implications: Realistic board games can create opportunities for social learning and training of groups which are not always easy to reach. Practical implications: Board games can support transfer of knowledge and skills to farmers, and can develop their critical thinking. Creation: The findings that board games are effective in the context of a top-down extension systems offer value opportunities.

Gender equality has been a political issue in view of human rights and welfare since several decades. Therefore, many countries have developed Gender Action Plans (GAPs) that support equal access of both sexes to education, employment and finance. Two workshops on GAPs in aquaculture and a literature review brought about the question: what's missing in Asian sectoral GAPs. Not all reviewed Asian countries have GAPs for fishery/ aquaculture, but all encountered constraints to achieve their goals regarding equal access for women. Women's contribution in aquaculture tends to go beyond the traditional gender divide. For example, women may lead in the area of production because they can combine aquaculture with their homebound tasks and own vertically integrated companies. However, skewed perceptions on the role, status and perception of women and men, more so in strong than weak patriarchies (the former accept the subservient role, while the latter exercise the dominant role) limit women's access to training opportunities on new aquaculture technologies. Women are also left out in policy- and decision-making processes; and in the value chain, women receive lower wages than men. Their role is underestimated by lack of disaggregated data, as reflected in post-disaster interventions and industrial development programs. To be effective sectoral GAPs, based on disaggregated data, should have budgets, plans and target indicators for which leaders could be held accountable. These GAPs, however, can't address the required radical change in attitude toward women; unless deliberately planned educational media campaigns are embedded into the national GAPs.

The use of serious games in the governance of natural resources and the environment is progressively increasing and includes games used for research and data collection, teaching and training, and fostering a change of practices. However, this diversity remains underexplored and underreported. In view of a growing interest in the use of serious games in natural resource and environmental governance, the absence of discussions about how differences in intended use and delivery influence the performance, assessment, and outcomes of games is problematic. Here we present an inventory, and a description, of such different uses then, by focusing on serious games used as interventions, we discuss when, and how, games could be used to generate learning and social learning. To that end we use a narrative review of selected literature, and insight from research on social learning, to develop an inventory of game use, and within that inventory we conceptualize the use of serious games as a social learning intervention. Also, by means of an illustrative case of a serious game (developed as part of the Assessing the Learning Effects of Games on Attitude of Stakeholders toward Sustainable Shrimp Farming – ALEGAMS research project) we reflect on a few key aspects of game use. We suggest that developing a serious game needs several iterations and, although the learning outcomes can be assessed, the impact of games aiming at changes in current practice and policy will likely fall beyond the timespan of usual project periods. This is something future research should consider as it has implications for the research design and methodology.

Shrimp farming in Demak, Indonesia is often practiced in silvo-aquaculture systems in which mangrove trees are planted on pond bunds. As such, mangrove leaves and its substrates may have impact on penaeid shrimp production. In this area, mangrove re-growth proceeded with Avicennia marina while planting is mostly done with Rhizophora apiculata. We compared the effects of decomposing fresh leaves of A. marina and R. apiculata on water quality and on the performance of Penaeus monodon postlarvae (PL). A hundred of PL21 (postlarvae aged 21 days with weight of 0.28 g) were stocked in each of 30 aerated tanks containing 800 liters of brackish water (salinity of 21 ppt) for 37 days. Five treatments with three replicates for each mangrove species were assigned by adding into the tanks of 0.125, 0.25, and 0.5 g L-1 of air-dried leave, 0.125 of g L-1 minced leave and 0.125 g L-1 of leachate of minced leaves. The PLs were fed 3 times daily with pellets at 10 % of initial total body weight. Water quality parameters were recorded daily. Tannin, H2S and NH3-N concentrations were measured every ten days. Prawn’s body weight (BW) was measured and specific growth rate (SGR, % day-1) and survival rate (SR, %) were calculated after the end of experiment. Results were analyzed with ANOVA and Pearson’s correlation. The results showed that tannin in decomposing mangrove leaf litter up to a concentration of 0.5 mg g-1 did not have a significant effect on water quality and on the growth and survival of P. monodon PL. However, increasing leaf litter concentrations showed an increase in NH3-N concentration due to organic matter degradation. The accumulation of NH3-N may have caused the slow growth of shrimp PL in A. marina treatment. Shrimp PL in leaf litter leachates treatment has a higher growth rate than those PL in regular leaf litter in relation to nutritional value. Survival and growth varied from 62 ±14 to 70 ± 8% and 3.1±2.1 to 5.5±1.2% day-1, respectively. Although decomposing mangr

The technical efficiency of randomly sampled pangasius farms in the Mekong Delta of Vietnam was estimated using data envelopment analysis, and factors affecting technical and scale efficiency were examined with bootstrap truncated regression. The mean technical efficiency score assuming variable returns to scale was 0.84. The technical efficiency of downstream farmers was higher due to lower energy costs and stocking once a year. Most of the up‐ and midstream farms needed to pump water and stocked at least three times in 2 yr. Regression analysis showed a positive effect on technical efficiency of the farmers' education level and having experienced climate change impact through flooding or salinity intrusion in the past. Farms affected by salinity intrusion had a lower scale efficiency as they reduce stocking frequency and rate. In general, reducing fish mortality and the cost of inputs, increasing scale of operation, and being trained, using appropriate methods, in management strategies may improve technical efficiency.

Vietnamese pangasius farming needs to produce efficiently to compete in world markets. This study investigates the input- and output-specific technical inefficiency of Vietnamese pangasius farmers. First, we used a Russell-type (input–output) directional distance function to estimate the input- and output-specific technical inefficiency. Second, we applied a bootstrap truncated regression to analyze the factors influencing these technical inefficiencies. Results show that the main challenges for enhancing the performance of Vietnamese pangasius production are inadequate use of capital assets (inefficiency of 42%) and improper methods to achieve higher fish yield (inefficiency of 30%). Input-specific technical inefficiency (pond area and feed) is negatively associated with the experience and education level of pangasius farmers. Location of the farm in a saltwater intrusion area is positively associated with the inefficiency of producing fish. Outcomes of this study are useful to identify successful strategies to minimize the use of inputs while simultaneously maximizing fish production.

The neonicotinoid insecticide imidacloprid is used in Bangladesh for a variety of crop protection purposes. Imidacloprid may contaminate aquatic ecosystems via spray drift, surface runoff and ground water leaching. The present study aimed at assessing the fate and effects of imidacloprid on structural (phytoplankton, zooplankton, macroinvertebrates and periphyton) and functional (organic matter decomposition) endpoints of freshwater, sub-tropical ecosystems in Bangladesh. Imidacloprid was applied weekly to 16 freshwater microcosms (PVC tanks containing 400 L de-chlorinated tap water) at nominal concentrations of 0, 30, 300, 3000 ng/L over a period of 4 weeks. Results indicated that imidacloprid concentrations from the microcosm water column declined rapidly. Univariate and multivariate analysis showed significant effects of imidacloprid on the zooplankton and macroinvertebrate community, some individual phytoplankton taxa, and water quality variables (i.e. DO, alkalinity, ammonia and nitrate), with Cloeon sp., Diaptomus sp. and Keratella sp. being the most affected species, i.e. showing lower abundance values in all treatments compared to the control. The observed high sensitivity of Cloeon sp. and Diaptomus sp. was confirmed by the results of single species tests. No significant effects were observed on the species composition of the phytoplankton, periphyton biomass and organic matter decomposition for any of the sampling days. Our study indicates that (sub-)tropical aquatic ecosystems can be much more sensitive to imidacloprid compared to temperate ones.

Gracilaria verrucosa is one of the Rhodophyta, it has an economic value and major aquaculture commodity in Indonesia which the production had increased between 2010 and 2014. Agar is one of the hydrocolloid extracts from Gracilaria, which the quality depends on the strain, cultivation methods and the water quality. This research compares three cultivation methods (broadcast, off-bottom and long-line) and two seedling types (local versus tissue cultured). After 60 days of cultivation, the Specific Growth Rates (SGRs), the agar content and gel strength were determined. The SGR (%d-1) of the local seedlings was higher than that of the tissue-cultured for all three culture methods: 1.2-1.3 and 0.5-1.1, respectively, probably due to adaptation problems. Overall, broadcasting resulted in a significantly higher agar content (9.6%) compared to off-bottom (6%) and long-line (3.2%), because of the low amount of light compared to photosynthesis, translating to less cell walls and more accumulation of carrageenan farther from the water surface. The gel strength of tissue-cultured seedlings in broadcast and off-bottom was significantly higher than that from long-line (505 compared to 201 g cm-2). The choice of seedlings and culture method may depend on the market price criteria and final use of the seaweed.

Pangasius production in Vietnam is widely known as a success story in aquaculture, the fastest growing global food system because of its tremendous expansion by volume, value and the number of international markets to which Pangasius has been exported in recent years. While certification schemes are becoming significant features of international fish trade and marketing, an increasing number of Pangasius producers have followed at least one of the certification schemes recognised by international markets to incorporate environmental and social sustainability practices in aquaculture, typically the Pangasius Aquaculture Dialogue (PAD) scheme certified by the Aquaculture Stewardship Council (ASC). An assessment of the environmental benefit of applying certification schemes on Pangasius production, however, is still needed. This article compared the environmental impact of ASC-certified versus non-ASC certified intensive Pangasius aquaculture, using a statistically supported LCA. We focused on both resource-related (water, land and total resources) and emissions-related (global warming, acidification, freshwater and marine eutrophication) categories. The ASC certification scheme was shown to be a good approach for determining adequate environmental sustainability, especially concerning emissions related categories, in Pangasius production. However, the non-ASC certified farms, due to the large spread, the impact (e.g., water resources and freshwater eutrophication) was possibly lower for a certain farm. However, this result was not generally prominent. Further improvements in intensive Pangasius production to inspire certification schemes are proposed, e.g., making the implementation of certification schemes more affordable, well-oriented and facilitated; reducing consumed feed amounts and of the incorporated share in fishmeal, especially domestic fishmeal, etc. However, their implementation should be vetted with key stakeholders to assess their feasibility.

This study investigated the perceptions on and adaptations to climate change impacts of 235 pangasius farmers in the Mekong Delta, Vietnam. Data were collected using semi-structured household surveys in six provinces, from three regions along the Mekong river branches. A Chi-Square test was used to determine the association between variables, and a logit regression model was employed to identify factors correlated with farmer’s perception and adaptation. Less than half of respondents were concerned about climate change and sought suitable adaptation measures to alleviate its impacts. Improving information on climate change and introducing early warning systems could improve the adaptive capacity of pangasius farmers, in particularly for those farmers, who were not concerned yet. Farmers relied strongly on technical support from government agencies, but farmers in the coastal provinces did not express the need for training by these institutions. This contrasting result requires further assessment of the effectiveness of adaptation measures such as breeding salinity tolerant pangasius.

Balancing options for shrimp farming A landscape approach to investigate the future of shrimp farming in the Mekong Delta Olivier Joffre While providing an option for development in coastal areas, shrimp farming is usually associated with high environmental cost due to the loss of mangrove forest and high social cost as farmers suffer heavy financial losses due to disease outbreaks. Planning shrimp farming requires to integrate risk as well as social and environmental cost. This thesis, using the Mekong Delta as a case, presents an approach to investigate, with local stakeholders, options to plan a resilient and sustainable shrimp farming sector. First, Olivier Joffre analyzed the different shrimp production systems from economic point of view before analyzing farmer’s strategies and providing insights on drivers that will push or, at the opposite, constraint farmers to choose integrated mangrove shrimp systems. This knowledge was integrated in an Agent Based Model (ABM) that was calibrated using Role Playing Games (RPG). The effect of future scenarios and different policies on the farmers’ decisions was tested using a combination of RPG and ABM. For one coastal district of the Mekong Delta, the results showed that promotion of intensification of shrimp production has a high social cost and decreases the total production in the study area after 10 years. Policies for supporting the spread of integrated mangrove-shrimp systems, such as Payment for Ecosystem Services, or access to an organic value chain, are not strong enough to influence farmers’ decision toward adopting these systems. Without any adaptation to climate change a sharp decrease of the production is expected. The approach brought local farmers’ knowledge to the attention of decision makers.

Whitespot syndrome virus (WSSV) has caused severe production drops in the shrimp industry. Numerous scientific manuscripts deal with WSSV epidemiology, but reports on minimizing disease outbreaks through ecological means are rare. Industry stakeholders resorted to various innovative techniques to recover from heavy economic losses. Some shrimp farmers in the Philippines claimed that ‘greenwater’ (GW) technology could prevent disease outbreaks due to WSSV. The efficiency of the GW technology was evaluated by comparing three ponds using the GW culture technique with three ponds not using it. WSSV was detected only in one of the GW ponds and not in the non-GW ponds. No WSSV disease outbreak occurred, and no conclusion could be reached. In GW ponds, available soil sulphur content was lower; and in water, the observed counts of luminous bacteria were lower and counts of Chlorophyceae were higher. Chlorophyceae, i.e. algae, enhanced nutrient uptake in effluent streams resulting in improved water quality in Penaeus monodon Fabricius culture ponds. This suggests that the use of the GW technique to culture P. monodon improved water quality.

Vietnam is among the top five countries that will be most affected by sea level rise. This study aimed to assess the subsequent impacts of flooding and salinity intrusion on, and to evaluate suitable adaptation strategies for the Mekong Delta's pangasius farming sector. Water level rise and salt water intrusion for three sea level rise (SLR) scenarios (i.e. +30cm, +50cm and +75cm) were simulated by using the MIKE11 model. The results showed that at SLR+50, the 3m flood level would spread downstream and threaten farms located in upstream and midstream regions. Rising salinity for SLR+75 would reduce the appropriate time-window for the culture in coastal areas. A Chi-Square test and a logit regression model were employed to examine factors which influence pangasius farmers’ perception of and adaptation to climate change impacts. Less than half of the respondents were concerned about climate change and actively sought suitable adaptation measures to alleviate its impacts. The adaptive capacity of pangasius farmers can be improved by increasing the information on climate change and introducing early warning systems. The technical efficiency (TE) of randomly sampled pangasius farms was estimated using Data Envelopment Analysis, and factors affecting technical and scale efficiency were examined with bootstrap truncated regression. The mean TE score assuming constant return to scale was 0.66, and under variable return to scale it was 0.84. TE of downstream farms was higher compared to the upstream and midstream farms due to lower energy costs and stocking once a year at a lower density, but these reduced the scale efficiency of farms affected by salinity intrusion. Upstream and midstream farms needed to pump water and stocked at least three times in two years. Regression analysis showed a positive effect on TE of the farmer’s education level, and of having experienced climate change impact through flooding or salinity intrusion in the past. Using a decision tree f

To reduce disease impact, Philippine farmers developed the green-water (GW) system, which has been spreading rapidly since 2008. In the most applied GW-system, the shrimp pond receives water from a reservoir stocked with tilapia. We collected financial data on GW and non-GW systems from farms having similar management and environmental context. All farms had more than one pond; the average pond area was < 1 ha, and total pond areas per farm ranged from 1.4 to 139 ha. The total variable and fixed costs per ha of shrimp pond were not different for GW and non-GW farms, but on GW farms the cost per kg of shrimp produced was lower. The latter was higher than the 2009 market price of 30 g shrimp for non-GW farms mainly. In GW farms the cost of seed was lower, and survival rates and individual shrimp weights at harvest were higher for an equally long culture period.

The white spot syndrome virus (WSSV) affecting shrimp aquaculture in most producing countries has caused huge economic losses resulting in bankruptcy to both large and small farmers. Studies done on WSSV epidemiology were mostly tank-based and on species other than Penaeus monodon. There is a need to investigate WSSV epidemiology in P. monodon in on-farm situations, thus including both risk and protective factors. This thesis aimed to generate knowledge that can improve prevention against WSSV in shrimp culture through better farm husbandry by studying the epidemiology of WSSV in on-farm situations. To achieve this goal data from cross-sectional and case studies were analysed to identify on-farm WSSV risk and protective factors, and longitudinal studies were done to assess factors affecting water quality and causing WSSV infection to result in an outbreak. The thesis identified the following WSSV risk factors related to the physico-chemical parameters of the water: low and fluctuating temperature, low and fluctuating salinity, and pH fluctuation. The risk of high temperature and high salinity for an outbreak of WSV disease may be related to fluctuations in these two parameters. Risk factors related to farm husbandry techniques were feeding with molluscs, sludge removal and its deposition on the dike, sharing water source with other farms and having the same receiving and intake water. Identified WSSV protective factors were high mangrove to pond area ratio, feeding with natural food or phytoplankton, and higher percentage of beneficial bacteria like the yellow colonies that grow on thiosulphate citrate bilesalt sucrose agar, a Vibrio selective medium. Results of the longitudinal studies demonstrated that WSSV infection may not result in outbreaks in greenwater pond and in ponds with mangroves in the receiving environment. Our results did not provide explanations why the WSSV infection did not result in an outbreak in farms with mangroves in the receiving environment

White spot syndrome virus is the most important among the shrimp diseases. It has been devastating the shrimp industry for more than 3 decades. Previous studies reported that greater percentage of yellow colonies on thiosulfate citrate bile salt sucrose agar (yellow vibrios) in the rearing water, abundant supply of natural food such as Chlorella, and the use of the greenwater technology (GW) are some ecological ways of preventing WSSV outbreak. The aim of this study was to investigate the efficiency of the 3 systems against WSSV. Shrimp, experimentally infected with WSSV by feeding with WSSV positive shrimp carcass, was cultured in tanks using three treatments: with tilapia to simulate the GW, seeded with Chlorella, and with molasses added to enhance growth of yellow vibrios. Shrimp cultured in seawater served as the control. Survival was recorded and shrimp were analyzed for WSSV quantification using qPCR upon termination. Analysis showed no significant differences in shrimp survival at 120 h post infection in all treatments and the control. However, from the original viral load of 1.40 × 101 WSSV/mg sample, WSSV decreased and was significantly lowest in shrimp cultured using GW (7.0 × 100), compared to the control (4.82 × 105) and the other treatments (3.66 × 105 for molasses added and 4.64 × 105 for Chlorella seeded) in which viral load increased 4–5 times. Shrimp survival was highest in Chlorella seeded treatment and lowest in GW. Nitrogenous waste concentrations were lowest in molasses added water and highest in GW. Results suggest that the GW culture technology provides protection against WSSV while addition of molasses lowers nitrogenous waste concentration. The use of GW in combination with the addition of molasses for shrimp culture is suggested.

White spot syndrome virus (WSSV) has been affecting the shrimp industry worldwide for two decades now. It continues to bring economic losses to affected farms. Despite the many studies on its epidemiology, there is no proven treatment or control measure. Diseases, like the WSSV, results from the interaction of three factors: host, pathogen and environment. The environment plays an important role in disease development and determines the health or the immune capacity of the shrimp. High mangrove-to-pond area ratio (MPR) is reported as a protective factor against WSSV. This study investigates if mangroves affect the physicochemical properties of the water and soil as well as the prevalence of infectious agents like the WSSV by monitoring farms with different MPR (0:1, 1:1, 4:1). Results showed that quality of influent water was not significantly better in farms with high MPR. Significantly higher available sulfur was observed in MPR-4; significantly higher percentage green vibrios in the soil in MPR-0. WSSV was detected in farms with MPR-1 and MPR-4 but did not result in an outbreak, suggesting that the presence of mangroves could prevent WSSV outbreak.

This paper presents a post-hoc assessment of the introduction of intensive shrimp farming strategies, with and without green-water (GW) technology, in the Mahakam Delta where extensive systems (ES) dominate. The study also assesses the potential of integrated mangrove GW shrimp production (MGW). The method section describes the systems considered, the cost-benefit analysis applied and the assumptions for different scenarios. The data for the GW and non-GW systems were based on a survey in the Philippines. Assessing cultured shrimp yields from the total farm area showed that production from non-GW was 10% higher than from GW farms. Compared to these two systems, the MGW system produces about 20% of the total shrimp, but provides complementary livelihood options and ecosystem services. Per unit area covered, MGW system produces 20 times more shrimp than ES, while income for farmers doubles and opportunities for livelihoods enhancement associated with the mangrove area increase. Low operating costs make the ES interesting for resource poor farmers, but risks to producers and societal cost are underrated. Transferring from ES to MGW system will increase the contribution to the national economy whilst maintaining ecosystem services, that would otherwise be lost, were intensive culture systems to predominate.

White spot sydrome virus (WSSV) is one of the most important viral disease of shrimp. Several studies to control the disease have been done. Tank experiments identified WSSV risk factors related to the physico chemical properties of the water. A few studies reported pond level WSSV risk factors. This study identifies the risk factors associated with essentially two different farming systems: polyculture and semi-intensive monoculture of Penaeus monodon. Data were gathered from a total of 174 shrimp farmers in eight provinces of the Philippines using a structured questionnaire. Forty-seven variables related to pond history and site description, period of culture, pond preparation techniques, water management, culture methods, feed and other inputs, and biosecurity measures were investigated. In the analysis for combined monoculture and polyculture farms, feeding live molluscs was identified as important WSSV risk factors. In addition to feeding live molluscs, sharing of water source with other farms, having the same receiving and water source, larger pond size, and higher stocking density were identified as important WSSV risk factors in monoculture farms. Climate, i.e. stocking during the cold months and sludge removal and its deposition on the dikes were identified as WSSV risk factors in polyculture farms. Protective factors, listed in decreasing significance, were feeding with planktons and high mangrove to pond area ratio, both observed in the dataset with both monoculture and polyculture farms, while only the latter was observed in the dataset for monoculture farms only. No protective factor was observed in the dataset for polyculture farms. This study confirmed the negative effect of sharing water source with other farms and identified several new factors influencing WSSV infection such as feeding live molluscs increases the risk, while feeding with planktons and high mangrove to pond area ratio reduce the risk.

Whitespot syndrome virus, WSSV, is the most important among the shrimp diseases. One of the suggested WSSV risk factors is the occurrence of stress since stressors could compromise the shrimp defence system thus increasing the risk of WSSV infection. Stressors are usually related to the physico-chemical properties of both water and pond bottom. This paper investigates the effect of some biotic and abiotic components of the pond ecosystem on WSSV infection and outbreak. Water physico-chemical properties and microflora of 91 production cycles of 8 semi-intensive shrimp farms were analyzed to determine WSSV risk factors, using factor analysis and logistic regression. Fluctuations of temperature and pH are important risk factors that will result to an infection but not necessarily to an outbreak. Exposure to high salinity and high temperature are important factors for an infection to result to an outbreak. The risk of an infection is reduced when the water temperature is high, salinity fluctuations are small, and percentage of yellow Vibrio colonies is greater than the green ones. Further studies are needed to clarify the effects of water depth, water transparency, and various bacterial counts; these factors could be individual or interactive.