Good Aquaculture Practices Research Articles

Adoption Level of Good Aquaculture Practices in Brackish Water Pond Aquaculture, Pinrang Regency, South Sulawesi Province

Pinrang Regency is a center of brackish water pond aquaculture production in South Sulawesi Province in which some of brackish water pond farmers in this regency have adopted Good Aquaculture Practices (GAqP). A study was conducted to determine GAqP adoption level, to identify GAqP aspects required to be improved, and to determine the category of GAqP adoption level as the first step to maximize the GAqP adoption level in the brackish water ponds. Primary data were obtained from 76 respondents consisted of pond farmers who already have adopted and or obtained GAqP certificates. On the basis of the adoption level, the adoption level classification is carried out into three categories, namely low adopters, medium adopters, and high adopters. The results showed that the highest GAqP adoption levels in brackish water ponds were in food security (89.41%) and technical aspects (78.57%). The lowest GAqP adoption levels were in management (8.71%) and environmental aspects (0%). It was also reported that the GAqP adoption level in brackish water ponds varied from 40.58 to 67.01% with an average of 42.86% and was categorized as moderate adopters. Based on this study, management and environmental aspects were found to be the aspects that need serious attention to increase the GAqP adoption level in the brackish water ponds.

Optimization of dietary protein level for good aquaculture practice based carp fattening in ponds under drought prone area of Bangladesh

Good aquaculture practice (GAP) based carp fattening is a potential technique to obtain higher and safe fish production within shorter period in ponds of drought prone area. Sustainability of this technique, however, is constrained by high feed cost and poor water quality. Therefore, as an overcoming effort, three diets (protein content of 20%, 25% and 30%) under three different treatments (T1, T2 and T3) were tested during January-June, 2020 in fattening ponds of carps (Catla, Gibelion catla; silver carp, Hypophthalmichthys molitrix; rohu, Labeo rohita; mrigal, Cirrhinus cirrhosis; and carpio, Cyprinus carpio var. specularis) under Rajshahi district, Bangladesh. Variation in protein level had no significant effect on environmental parameters of pond water. Combined fish yield was found to vary significantly (P<0.05) among the treatments, while feed conversion ratio did not vary significantly. Although second degree polynomial regression analysis identified 28.50% dietary protein for optimal growth of carps but no significant difference between T2 and T3 was found for the total fish yield. However, significantly (P<0.05) highest cost-benefit ratio obtained with the diet containing 25% protein suggested this protein level in diet was profitable for carp fattening in pond.

Culture practices and health management issues in selected aquafarms of Rajbari, Bangladesh: A preliminary study

The current study was conducted to determine the existing fish culture systems and health management practices in the selected aquafarms of Rajbari District, Bangladesh. Data were collected from 50 fish farmers from October 2019 to February 2020 using questionnaire interview, focus group discussion and crosscheck interview. It was found that most of the aqua farmers had 11 to 15 years’ experience of fish farming and more than 30% had their own ponds. The farmers used to prepare ponds for stocking by several steps like pond drying, bottom mud removal, dyke construction, liming, fertilizer application, and finally stocking. Only 20% fish farmers stocked single fish species like pangas and tilapia, whereas other used to stock two to eight types fish species. Most of the fish farmers sell the harvested fishes either in the local or in city markets. Major fish health problems in the study area were infectious and non-infectious diseases occurred due to bacteria, virus, fungus, parasites, unfavorable water quality and malnutrition. Majority (94%) of the farmers did not have water quality measurement tools. However, the major health problems of fish were ranked by the farmers on the basis of critical condition where fish disease, poor water quality, fish killing as a part of enmity, entrance of wild animal and hamper due to fish eating birds were ranked as 1st, 2nd, 3rd, 4th and 5th utmost constraints, respectively. Forty-four percent and 20% respondents received training on different aquaculture techniques from Government and nongovernment organizations, respectively. While during disease outbreak, most of them received technical assistance from the culture fellows. The fish farmers of the study area were not aware of good aquaculture practice maintainingbiosecurity. The present study revealed that there is a lack of scientific knowledge of the fish farmers in the studied areas which demands further improvements of the existing condition.

5R-BASED CHARACTER STRENGTHENING MODEL TO SUPPORT HALAL AQUACULTURE INDUSTRY PRACTITIONERS THROUGH GOOD WATER QUALITY MANAGEMENT AND SAFE MACHINERY OPERATION

This research aims to design 5R character-based halal industry players (Ringkas, Rapi, Resik, Rawat, Rajin) or 5S (Sort, Set in Order, Shine, Standardize, Sustain), as well as their debriefing for UNY and IIUM students in supporting the Halal industry related to Good Aquaculture Practices. This area has been selected, due to some factors. The first is the occurrence of several cases of aquaculture products that changed status from being permissible to become impermissible due to the external factors, for example, the fact that the water quality is bad and contaminated with harmful chemical substances. Water quality is the most important factor affecting fish health and performance in aquaculture production system. Secondly the fish nutrition and feeding are mixed with unclean and filthy ingredients. Thirdly, it is exposed to the risk of contamination from the equipment, which eventually affects halal integrity. Halal products cannot be prepared, processed, or manufactured using equipment that is contaminated with non-halal substances (unclean defined by Shariah). Contamination can be caused by equipment that is contaminated or used together with non-halal products. Therefore, equipment and machinery used in the halal aquaculture industry play a very important role to ensure halal integrity. This paper uses a library and literature review approach. It is expected that with the arrangement of 5R or 5S-based character strengthening design, the operators of Aquaculture Industry may preserve Halal Supply Chain.

5R-BASED CHARACTER STRENGTHENING MODEL TO SUPPORT HALAL AQUACULTURE INDUSTRY PRACTITIONERS THROUGH GOOD WATER QUALITY MANAGEMENT AND SAFE MACHINERY OPERATION

This research aims to design 5R character-based halal industry players (Ringkas, Rapi, Resik, Rawat, Rajin) or 5S (Sort, Set in Order, Shine, Standardize, Sustain), as well as their debriefing for UNY and IIUM students in supporting the Halal industry related to Good Aquaculture Practices. This area has been selected, due to some factors. The first is the occurrence of several cases of aquaculture products that changed status from being permissible to become impermissible due to the external factors, for example, the fact that the water quality is bad and contaminated with harmful chemical substances. Water quality is the most important factor affecting fish health and performance in aquaculture production system. Secondly the fish nutrition and feeding are mixed with unclean and filthy ingredients. Thirdly, it is exposed to the risk of contamination from the equipment, which eventually affects halal integrity. Halal products cannot be prepared, processed, or manufactured using equipment that is contaminated with non-halal substances (unclean defined by Shariah). Contamination can be caused by equipment that is contaminated or used together with non-halal products. Therefore, equipment and machinery used in the halal aquaculture industry play a very important role to ensure halal integrity. This paper uses a library and literature review approach. It is expected that with the arrangement of 5R or 5S-based character strengthening design, the operators of Aquaculture Industry may preserve Halal Supply Chain.

Status of Water Quality in Fishponds Surrounding Manila Bay

Fishponds around Manila Bay contributed an average of 41.19% of the total aquaculture production in the country. However, massive productions entail the intensification of ponds, which resulted in water quality deterioration. In 2016, Opinion et al. reported water quality in the aquaculture farms around the bay but does not include the other significant parameters required to be monitored, as stated in the DENR AO (2016). Thus, this study investigated the status of water quality in different pond systems surrounding Manila Bay. Extensive, semi-intensive, and intensive fishponds from adjoining provinces of Cavite, Pampanga, Bataan, and Bulacan were monitored throughout the rearing period. Results showed that levels of NH3-N (0.90 mg/L – 2.35 mg/L) and PO4-3 (1.02 mg/L – 2.42 mg/L) were not suitable for the culture of fish. Nevertheless, NO3-N, NO2-N BOD, TSS, DO, pH, and temperature were within the safe levels. Furthermore, results suggested that there should be a regular monitoring of water quality to regulate and manage fishponds surrounding the bay. Finally, strict compliance of the Code of Good Aquaculture Practices (GAqP) must be imposed to achieve water quality standards.

Correlation between socio-demographic characteristics and adoption rate of good aquaculture practices in traditional technology-based fishpond in Pinrang Regency

Fishpond farmers in Pinrang Regency, South Sulawesi Province, have adopted Good Aquaculture Practices - GAqP (CBIB in Indonesian), yet the adoption rate of CBIB by traditional fish farmers still fell under the moderate adoption criteria. Therefore, a study aimed at analyzing the correlation between socio-demographic factors and adoption rate in hopes that the adoption of CbBIB can be increased that will have implication for the sustainability of aquaculture besides improving the quantity and quality of products, including food safety. The research method applied was a survey method to obtain primary data collected by structurally distributing questionnaires to respondents. Primary data in the form of socio-demographic characteristics of CBIB adopters and other data, namely the adoption rate of CBIB, were sourced from data reported by Mustafa et al. (2019). To measure the closeness of the relationship between socio-demographic characteristics and adoption rate, a statistical test of Spearman’s Rank correlation coefficient was used. The CBIB adoption rate by fish farmers in Lanrisang and Mattiro Sompe Subdistricts of Pinrang Regency was found to be in the moderate adoption category (adoption rate of 33.34-66.66%). CBIB adopters were all-male, 48.68% aged between 40 and 49 years, 56.58% graduated from high school, 36.84% adopted CBIB less than two years, and 53.95% managed ponds in an area of 1.0-1.9 ha. Moreover, results also showed that five socio-demographic characteristics of CBIB adopters, namely gender, age, education level, length of adoption, and pond area, did not have a significant correlation with the CBIB adoption rate in the ponds of Pinrang Regency. It is recommended to conduct further research by examining other variables of socio-demographic characteristics in addition to the economic aspects of traditional fish farmers to determine their effects on the adoption rate of CBIB.

Shrimp/prawn farming status in south-west region of Bangladesh in context of quality control and food safety issues

To determine hazardous antibiotics/chemicals and pesticides residues in Good Aquaculture Practice(GAP) and non-GAP farms and exploring the post-harvest management techniques of shrimp/ prawn forensuring its food safety issues, a study was conducted from July 2016 to June 2019 in three upazilas viz.Bagerhat Sadar, Rampal and Kachua of Bagerhat district. A total of 550 shrimp/prawn farms were randomlysurveyed considering GAP criteria. The farms were categorized as Category A- the farms which comply 90-100% GAP criteria; Category B- farms which comply 70-< 90% GAP criteria and Category C- farms whichcomply 50-<70% GAP criteria. From the study it was found that only 1.67±0.58 % farms were underCategory-A, 37.67±6.81 % farms were under Category-B and 53±6.08 % farms were under Category-C. Atotal of 108 shrimp/prawn samples were collected in which 30% samples were from GAP farms and 70%samples were from non-GAP farms. Collected samples were analyzed for hazardous antibiotics/chemicals andpesticides residues (Heptachlor, Endrin, Dieldrin and DDT) using LC-MS and GC-MS machine. Nohazardous Nitrofuran and Chloramphenicol metabolites were found from the collected samples and noresidual concentrations of Heptachlor, Endrin, Dieldrin and DDT were found from GAP samples. In non-GAP samples, 14.8% samples contained some residues of Heptachlor, Endrin and Dieldrin in which 10.2%samples residues were lower than the Maximum Residual Limit (MRL) which is not harmful for humanhealth. Only 4.6% samples had residues which were slightly higher than the MRL. Exploration of postharvestmanagement techniques of shrimp and prawn were done by observing the icing system quality andtransportation system from farms to market/depot. It was found that 5.67±2.08% farmer used proper icingand transportation system as well, 16.33±3.21% farmers used moderate icing and transportation system and78±2% farmers used poor icing and transportation system. It was also observed that pathogenic bacterialload was higher in poor icing and transportation system as well than the proper icing and transportationsystem. From the study it can be concluded that, if farmers follow at least 50% of the GAP criteria then thefoods (shrimp/prawn) will be safer for human consumption.

Determination of suitable species combination for good aquaculture practice based carp fattening in ponds under drought prone barind area of Bangladesh

Increased temperature, decreased water level and reduced culture period of the ponds with lack of guidelines in selecting appropriate stocking size, density and combination of species are major constraints for safe production of fattening based carps in drought prone barind area of Bangladesh. In order to address these problems, an experiment was conducted during July-December, 2018 to determine the suitable species combination for fattening ponds of overwintered carps in Tanore upazila (sub district) of Rajshahi district, Bangladesh. Three different combinations of surface (G. catla and H. molitrix), column (L. rohita) and bottom (C. cirrhosus and C. carpio var. specularis) feeding carp species were tested under 3 treatments (T1, T2 and T3), each with 3 replications: T1 (Surface-30%, column-40%, and bottom-30%), T2 (Surface-40%, column-30%, and bottom-30%) and T3 (Surface-35%, column-35%, and bottom-30%). Application of good aquaculture practices in the studied ponds was found to improve the environmental conditions of pond. Significantly (P< 0.05) highest fish yield was obtained from treatment T2 which was 21.47% and 11.89% higher than T1 and T3, respectively. Significantly (P<0.05) highest cost benefit ratio was recorded with treatment T2 (0.42±0.02) followed by T3 (0.31±0.01) and T1 (0.21±0.01), respectively. Inclusion of appropriate number of fishes at different water layers of pond favoured the yield and economics of carp fattening. The study also suggests focusing on optimal stocking density together with the formulation of low cost feed for carp fattening in ponds under barind area of Bangladesh.

Quality Management Practices of Intensive Whiteleg Shrimp (Litopenaeus vannamei) Farming: A Study of the Mekong Delta, Vietnam

Continuous warnings on quality and food safety of shrimp products from importers have led to increases in port rejections. This has increased awareness amongst Vietnamese farmers for conducting shrimp farming according to specific certification guidelines. The purpose of this paper is to clarify the situation of quality control and effectiveness of Good Aquaculture Practices (GAP) in Vietnam (VietGAP) for intensive shrimp systems by making a comparison between VietGAP and non-GAP applied farms. The farmers in the GAP system performed well on seven control points related to quality management, especially regarding reservoir construction, water monitoring, and chemical use. Of the farms, 49% reported disease, and the ratio of safety rejections was low. The farmers in non-GAP farms appeared to have weak practices in quality control with high usage of antibiotics, leading to 64% of farmers reporting disease and 20% of tested shipments being rejected. The VietGAP applied system has the potential to deal with disease and quality problems to increase export opportunity for Vannamei shrimp. However, VietGAP does not generate a high price premium in itself because it is not a recognized certificate in the global markets. The results reinforce previous findings regarding eco-certification and how it can be a useful tool to reduce small-scale producers’ risk, even though it does not necessarily generate a price premium.

Analysis of biosecurity-related policies governing the seaweed industry of the Philippines

The seaweed industry in the Philippines is a significant contributor to aquaculture production, both nationally and internationally. It out-produces the capture fisheries sector and most global producers, with the exception of China and Indonesia. Seaweed species, particularly Kappaphycus and Eucheuma spp., have been farmed throughout the country since the early 1970s. In 2017, the Philippines produced 1.4 million tonnes (fwt) and exported 35,490 tonnes of seaweed and carrageenan with a value of US$174 million. However, a decreasing trend in seaweed production has been observed since the mid-2000s as a result of pest and disease outbreaks, among other factors, which have been exacerbated by climate change. This paper is the first to analyze biosecurity-related national policies and legislation (a.k.a. ‘frameworks’ collectively), which are relevant to the seaweed industry in the Philippines. A total of 12 frameworks were identified, of which a sub-set of seven were compared using defined biosecurity themes, risks, and management measures to evaluate how seaweed biosecurity is incorporated into national policy. The inclusion of biosecurity-related activities in national frameworks was found to be limited to aquatic animal commodities or agricultural crops. Only the Code of Good Aquaculture Practices (GAqP) for seaweed specifically included seaweed cultivation, however, it did not include any biosecurity measures. The results indicated a clear gap in current biosecurity legislation and policy in the Philippines, which if addressed have the potential to reduce the impact of endemic and emergent diseases and pests and support the sustainable growth of this important industry.

Nature’s Sustainable Aqua Gift — Pearl in Unani medicine

Unani medical system is a holistic approach of science and human body. It is a natural and simple method of extracting from nature and based on the way body responses. Although several researches are working to find solutions for many diseases, this system still have not gained the popularity in the modern world for the developers in this field and beneficial for the patients. This paper explains the importance of sustaining the Unani system and drugs made from component (Pearl- Marwareed) obtained from marine animal, providing insight on good aquaculture practice in India. Hence, exploring the Islamic perspective of Unani medicine, the safety contour of the drugs and the usage of pearl in its preparation. The data were collected from personal interview with Hakeem (Physician with wisdom) across India and extensive literature as well as recommendation to promote Unani medical system in India. Significant sustainable strategies are suggested for further improvement in Aquaculture industry. We suggest policy makers and researchers focus more on implementation of best techniques and technology to develop Indian Aquaculture products and they usage in traditional medicinal system ‘Unani’

MyGAP: Malaysia’s gift to seafood world

Globalization, consumer expectations, sustainability of food production and sanitary and phytosanitary control measures from importing countries have been identified as a major challenge for the development of the aquaculture industry in the world. Currently, international trade trend has focusing to the production of safe for human consumption aquaculture products and produce which avoids the deterioration of the quality and sustainability of the environment. The United Nations Food and Agriculture Organization has published Aquaculture Certification Technical Guidelines in 2011 as a general global guidance for Good Aquaculture Practice certification. Malaysia has implemented the Certification of Good Aquaculture Practices in 2004 and has national standards since 2007 when Malaysia’s Standard (MS 1998: 2007) General Guidelines for Good Aquaculture Practices was officially publish for certification reference. Certification in Good Aquaculture Practices Malaysia requires farm owner to compulsorily participate in the National Aquaculture Residue Monitoring Program to verify aquaculture products from certified premises to be safe for human consumption and free from harmful contaminants. In 2017, the standards were revised to comply with ASEAN Good Aquaculture Practices (ASEAN GAqP) requirements.

Characterization of Fish Farming Practices and Performance: Baseline Study and Implications for Accelerating Aquaculture Development in Ghana

Over the past decade, the aquaculture sector in Ghana has experienced tremendous growth—driven mainly by large-scale cage farms—but it has been unclear how the rural poor have shared in this growth. A research project has been initiated to help diagnose, design, and test interventions for better inclusion of the rural poor, women, and youth in the tilapia value chain. This report describes the baseline data on 603 small-scale tilapia farmers in Ghana. The data collected during two-hour face-to-face interviews during May–July 2019 are disaggregated by socioeconomic indicators, gender, and age group. Baseline data show that 9 percent of farm managers and owners were women, and an additional 9 percent of farms engaged women in some decision-making. Moreover, women contributed 16 percent of family labor and 5 percent of hired labor on farms. Youth represented 14 and 24 percent of owners and managers, respectively, but contributed 68 percent of the total family and hired labor on farms. A large majority of managers and owners had at least high school education, with a third of owners and a quarter of managers attaining at least a college degree. In Brong Ahafo and Ashanti regions especially, most farmers engaged mainly in crop farming and non-farm businesses as their main livelihood, with fish farming as a small contributor to overall household income and livelihood. Farmers in all regions had poor record-keeping and management practices and low compliance with sanitation, fish health, and food safety standards. A wide variety of input usage, management practices, and performance was observed among fish farms. As a result, the profitability of fish farms was also wide-ranging, between –12.00 and 46.00 cedi per m2, with an average of 8.82 cedi per m2. Despite wide variability in production and profits, the majority of farmers experienced positive profits. On average, a farmer received a profit of 2.4 cedi per kilogram of tilapia produced or a 27 percent profit margin. These encouraging figures indicate that farmers who adopt good aquaculture practices can achieve respectable profits.

A value chain analysis of Malaysia\u2019s seaweed industry

A global shortfall in protein supply from capture fisheries has motivated the Malaysian government to revise its aquaculture strategy, focusing on three commodities: seaweed, fish and marine shrimp. However, the performance of the Malaysian aquaculture sector, particularly seaweed production, is poorly documented. This is the first empirical study to undertake a value chain analysis (VCA) of the Malaysian seaweed sector using stakeholder perceptions and secondary data that encompass members of seaweed farming cooperatives (the Semporna Area Farmers’ Association and the governments’ flagship Seaweed Cluster Project). Fieldwork was conducted between April and June 2015 among seaweed stakeholders involved in the value chain using a mixed methods approach—in-depth interviews with key informants, focus group discussions, household surveys, personal observation and secondary data. Qualitative and quantitative data were collected from both upstream (seaweed farming, marketing structure and the Malaysian Good Aquaculture Practices [MyGAP] certification programme) and downstream (seaweed processing) activities involving farmers, intermediaries/middlemen (buyers), processors and officials. Kappaphycus spp. was sold in two forms: (1) dried seaweed to be used as raw materials in carrageenan processing (approximately 90% of total harvest) and (2) fresh seaweed to be used as a source of seedlings (approximately 10% of total harvest). The value chain ended with the carrageenan form, which is exported to international markets. The price of dried seaweed varied according to a combination of seaweed quality, the strength of farmer’s relationships with intermediaries and processors and in response to demand from the carrageenan industry. The prices obtained by Malaysian farmers for dried seaweed and carrageenan remained low, US$ 0.60 and US$ 4.43 per kg, respectively, despite efforts by the government to enhance the value chain by imposing seaweed standards (via MyGAP) for farm management, dried seaweed and semi-refined carrageenan. The VCA was a useful tool to identify and map the market, with the results providing a better understanding of the seaweed sector, which could be helpful in supporting further aquaculture development in Malaysia.

Socio-Economic Assessment of Grouper Fishermen and Their Perceptions on Mariculture Development in Buleleng District, Bali, Indonesia

Various activities in the coastal area of Buleleng-Bali for many years affected to the sustainability of mariculture activities. This research aimed to 1) identify the problems of groupers farming in fish cages, 2) analyze the cost-benefit of grouper farming and 3) analyze fish farmer perceptions on mariculture development. Primary and secondary data were collected and analyzed by using descriptive, financial and Likert-type analyzes. The results show that the average production of grouper farming was 450 – 7500 kg per harvest. The main problems in groupers farming are related to uncertainty market demand in recent years, financial capital limitation, high price of fish feeding, and low productivity. Benefit-cost analysis revealed that the benefit-cost ratio is 1.92 (B/C ratio > 1) and the payback period (PP) is 2.3 years (project life assumption: 10 years) and the internal rate return (IRR) is 12%. It means that grouper farming is economically visible to develop in Buleleng District. Fish farmers as well as local stakeholders have positive perception and active participation in grouper farming using floating-fish cages. Fish farmers also needs special trainings related to disease management, seed selection, marketing, and good aquaculture practices. The main obstacles of price and capacity faced by farmers for using various sensors to reduce the risk of mass fish death and other climate change effects should be of special concern to local and central government to install a set of equipment to control and reduce the impact of environmental changes on all grouper floating cages.

Good Aquaculture Practices Adoption and Certification of Shrimp Aquaculture Farms in Bulacan, Philippines: Status, Issues and Prospects

Good Aquaculture Practices Adoption and Certification of Shrimp Aquaculture Farms in Bulacan, Philippines: Status, Issues and Prospects

Food safety impacts of finfish and crustacean aquaculture on food security in Asia.

Asia is the world's largest aquaculture producer. The aquaculture industry faces a multitude of threats ranging from microbiological and chemical to parasitic. These threats could potentially affect aquatic animal health and food safety and alter the consumer's perception of aquacultural produce. The development of antimicrobial resistance is also of increasing concern. These actual or perceived food safety threats could result in reductions in the food supply that adversely affect the food security of a country or region. Harmonised regional regulatory requirements, increased consumer awareness and the adoption of good aquaculture practices are ways in which the aquaculture industry can mitigate these risks. Together with the increased use of smart technology in production and encouragement to adopt certification and accreditation schemes, these tools can help the aquaculture industry in Asia to become more resilient in the face of such challenges. In this paper, the authors present an insight into the hazards faced by the aquaculture industry, which could potentially adversely affect food supply and hence food security, in an Asian context. The authors make several recommendations to mitigate these risks and thus safeguard against disruptions to regional food security.

Extrinsic Factors and Marine Bivalve Mass Mortalities: An Overview

Bivalve aquaculture accounts for 14%–16% of the average per capita animal protein of 1.5 billion people, supporting more than 200,000 livelihoods, mostly in developing countries. Massive mortality outbreaks of various cultured bivalves have been reported worldwide. Repeated episodes of mass mortality not only reduce the production and cause high economic losses but also have a negative impact on natural bivalve populations. The present article reviews the scientific evidence of mass mortality outbreaks of marine bivalve molluscs affected by extrinsic factors. It attempts to summarize the pertinent data published on specific research issues to improve understanding of the diverse factors. This helps to clarify the present state of research and to identify topics for future studies on bivalve mass mortality. It can be seen from the published data that bivalve mass mortality episodes are rarely caused by single factors but are more likely to be triggered by synergistic effects of two or more factors. Understanding these factors could aid in the development of good aquaculture practices and effective fishery management plans for bivalves.

Effect of network-based targeting on the diffusion of good aquaculture practices among shrimp producers in Vietnam

Abstract In developing countries, social networks play a critical role in the transmission of information about new technologies and influence an individual’s decision to adopt the technology. Thus, this study considered a case of shrimp farmers in Vietnam to identify whether the farmers’ networks have positive effects on diffusing accurate agricultural information to the treated farmers and their neighbors. To explore the effects, we invited farmers selected using network-based targeting to a workshop held in December 2017 and estimated it using data obtained before and after the treatment. We found that: 1) the targeting has a positive effect on the treated farmers’ knowledge level about a good aquaculture practice; 2) The treated farmers selected using the network-based targeting share information with more neighbors when they get new information; and 3) The targeting has a positive spillover effect on untreated farmers' knowledge level, but its effect is lower than other randomly selected. These findings can conclude that network-based targeting appears to be a method to disseminate information to many people. Nevertheless, the methods are less likely to deliver accurate information to a wider group of farmers than random sampling.