Advancing quality and health management practices in extensive shrimp (Penaeus monodon) farming in Bangladesh

This study used a random selection of 150 extensive shrimp farms in three areas in Bangladesh (Paikgacha, Dacope, and Chokoria) and questionnaires to examine the quality, hygiene, and sanitation practices that farmers used to satisfy national and international concerns. The majority (95.67%) of farmers in all three sites did not examine the quality of the hatchery-bred post larvae (PL) and felt that the hatchery used chemicals or antibiotics in producing PL and supplied under-aged PL (below PL15), resulting in significant mortality when released onto the farms. The majority of farmers (83.3%) performed a visual inspection, examining shrimp size, weight, and disease symptoms before harvesting. Farmers in Chokoria were better aware of the need of inspecting quality features (growth, disease, weight, and shell) before harvesting than farmers in Dacope and Paikgacha. Farmers frequently neglected the icing of caught shrimp at the request of the buyer. To reduce losses, they took action when collected shrimp exhibited indicators of low quality, such as the presence of spots (43.3%), fragile shells (37.3%), and accidental debris (88.7%). Shrimp producers also enhanced their quality standards by using 100% plastic crates to transport shrimp and by improving working surfaces (92%) to wash, sort, and sell the collected shrimp, and building sanitary restrooms (100%) at a safe distance from the farms. Farmers believed that new laws had forced them to enhance safety, hygiene, and sanitation standards in order to decrease the poor quality image of Bangladesh shrimp held by international buyers, despite higher operating expenses and lower profitability. • Black tiger shrimp (Penaeus monodon) is the majority farmed species, which is cultivated extensively across the coastal regions of Bangladesh. • This study assessed how shrimp farmers evaluated the quality of input supplies during the production and post-harvest stages. • Data from 150 shrimp farms in three different locations were collected using a questionnaire and analysed in Microsoft Excel and Statistical Package for Social Science software. • Pesticides or growth hormones were not used by farmers. Shrimp producers improved their quality standards by transporting shrimp in plastic crates, upgrading working surfaces for washing, sorting, and selling harvested shrimp. • Farmers were dissatisfied with the quality of hatchery PL. Farmers also lacked scientific knowledge on evaluating PL and shrimp quality on their farms, placing stock at risk of disease. • After harvesting, shrimp were exposed to ambient temperatures, and farmers frequently refrained from icing them at the request of the next purchasers such as forias or depots. The latter saw icing as increasing shrimp weight and hence purchase prices.


Introduction
Shrimp cultivation in brackish water is a long-established practice in coastal districts in Bangladesh. The black tiger shrimp (Penaeus monodon) is the most commonly farmed species, and it is cultivated extensively across the country's coastal regions. This system employs comparable production practices, such as low stocking densities, little or no external nutritional inputs, tidal water exchange, and poorer yields. Around 80% of the shrimp culture area is in the Khulna region of southwest Bangladesh, with the remaining 20% in the Cox's Bazar region in southeast Bangladesh (DOF 2019). Coastal shrimp farms have production variations due to factors such as farm age, poor water exchange, shallow water, salinity variations, fluctuating stocking densities, a lack of excellent quality PL, the presence of non-target species in farms, and diseases (Alam 2007;2004). There were 186,275 ha of shrimp cultivated land, with an average farm size of 1-4.5 ha and a 347 kg/ha annual output (DOF 2021).
Following the events of 1997, the European Union (EU) prohibited shrimp imports from Bangladesh. Following further inspections and actions by the Bangladesh government, it was discovered that shrimp farmers had taken a number of steps to preserve cleanliness and sanitation in order to comply with national and international standards, including EU directives (Alam 2010). These included keeping the temperature under control after harvesting, storing the shrimp in plastic containers, and removing unsanitary hanging toilets from the agricultural sites. Many farms were not registered with the Department of Fisheries (DOF), and so were not subject to any regulatory oversight. As a result, many farmers failed to maintain appropriate aquaculture practices.
This study looks at shrimp farm operators and shrimp farm organisations in the two areas, as well as how shrimp farmers rated the quality of input supply during the production and post-harvest phases.

Material and methods
The research approach was descriptive and analytical in examining the current situation of quality management in the Bangladesh shrimp supply chain in response to changing EU regulations. According to Caritas (1997), the following were the key categories of shrimp farm ownership in Bangladesh.
• Individual farm owner: The farm is owned and run by a single person.
• Group farm owner: The farm's land is owned by a group of people who actively manage the farm and share the revenue. • Outside lessee: The farm's land is leased by the owners to a person or people who live outside the polder area.
The study was conducted between February and May 2020 on 150 shrimp farms in three different locations with 50 farms from Paikgacha and 50 from Dacope in the southwest and 50 from Chokoria in the southeast of Bangladesh. Farmers from those shrimp farm ownerships were chosen randomly. The rationale for selecting those areas was that these areas have been producing shrimp for export for over five decades. Shrimp farmers in the southwest had gained knowledge and skill from government-run shrimp projects during different periods where farmers experienced in the areas related to shrimp production, food safety, and hygiene aspects, while farmers in the southeast lacked such experience as there had been no remarkable government fisheries project. The locations of the study areas are displayed on the Bangladesh map (Fig. 1).
The research used face to face interview approach with a questionnaire. The questionnaire contained close-ended and open-ended questions divided into a few sections. The questionnaire contained 84 questions divided into ten sections with 310 variables. The first two sections consisted of a profile of the interviewees and the farms. The third and fourth sections focused on production management with questions related to the use of fertilisers and chemical products during the grow-out phase and harvest control (use of ice, sanitising harvest, and storage equipment). The fifth and sixth sections were concerned with transportation and marketing and how the quality of the harvested shrimp was controlled. Sections seven and eight concerned the evaluation of the product and inspection procedures. Section nine was related to aspects of food safety, hygiene, and training while section ten sought to assess the impact of regulatory measures on the shrimp farms.
All the information collected was accumulated, grouped, and interpreted according to the objectives of the research. The data were analysed using Microsoft Excel and SPSS (Statistical Package for Social Science) 16.0 edition software. The formal process of qualitative data analysis and open-ended questions in respective questionnaires (specifically impact assessment) involved assigning codes according to the answers and the descriptors and then grouping them according to the themes generated. Descriptive statistics such as mean, frequency distribution, cross-tabulation, and charts were used for quantitative data analysis and presentation.

Farm ownership structures
The respondents who participated in this questionnaire and the interviews were mostly shrimp farm owners (61.39%), managers (28.32%), and cashiers (10.29%). The investigated shrimp farms belonged to two different ownership arrangements, i.e. individual Paikgacha Dacope Chokoria Fig. 1 Locations of the study area in Bangladesh map farms (70%) and group farms (30%). All of them had a long-term engagement in their respective shrimp farming practices.
About 59% of the individual farmers with smaller farm sizes (0.30-2.48 ha) had 6-10 years of experience in shrimp farming, while 33% had 1-5 years of experience and only 8% had 16-20 years of experience. In group farming with moderate farm size (1.35-12.56 ha), 27 (60%) of the groups had 6-10 years of experience, while 11 (24%) groups were found with 11-16 years of experience. Only seven (16%) groups had 16-20 years of experience. All of the respondents reported that shrimp farming was their major profession, with agricultural and shrimp-related businesses listed as supplementary jobs.

Characteristics of shrimp farming in two regions
Seasonal weather and ecological variations in the two locations determined the shrimp farming production calendar. Water salinity differences in the southwest and southeast regions of Bangladesh affected cultural practices and production times in both locations. In Khulna, shrimp farming has been practised during the dry months (February to mid-July), with multiple stocking and harvesting, followed by a crop of a local type of transplanted Aman paddy in the wet months (July/August to November/December) on the same area (Alam and Phillips 2004). Shrimp cultivation has been practised in Chittagong from May to November, followed by salt extraction (Fig. 2).
All farmers practised shrimp monoculture and used the same pond preparation procedures. The black tiger (Penaeus monodon) is locally known as Bagda, was the most often farmed species, although other shrimp species such as P. indicus, P. marguencis, Metapenaeus monoceros, and M. brevicornis were also cultured. Some finfish species also entered naturally as a result of water intake. The presence of non-target shrimp and finfish exposed one of the major challenges in ensuring shrimp monoculture under the extensive production method, affecting gross target species output per hectare. Farmers attempted to prevent exotic species of shrimp and fish from entering ponds in the early days of shrimp farming. However, when diseases affect the primary target species, farmers have shifted their focus to non-target species as a risk-aversion approach. Non-target species were sold by some, while others have used them for sustenance.
Farm size, fertiliser application rate, post larvae stocking densities, and water exchange rates differed amongst farms. Shrimp farming began with field preparation, which included constructing or repairing dykes encircling the farm and installing or repairing sluice gates  (2004) for water exchange. Farmers often stocked five to eight times every new and full moon. At the fifth or sixth stocking, they began harvesting the shrimp, and after each harvesting, they replenished the stock. As a result, they are harvested in stages sixteen to eighteen times every season.

Grow-out farm's inputs and management
Shrimp are raised under extensive conditions, mostly on natural food present on the farms. Farmers, on the other hand, employed liming and fertilisers to boost the growth of this natural food. The liming materials (agricultural lime-CaCO 3 ) were the first biological inputs used during the preparation of shrimp farms and throughout the farm management system. The lime was applied in varied dosages after drying and filling the farm with water. Farmers in Chokoria used the most lime (64.75 kg/ha), followed by farmers in Paikgacha (55.76 kg/ha) and Dacope (42.95 kg/ha). Sometimes farmers used lime as a water treatment agent against viral diseases.
Shrimp farmers used two categories of fertilisers-organic and inorganic. Nitrogen and phosphorus compounds were the most often used inorganic fertilisers, which were applied as a single component or as a combined fertiliser of the two compounds. Urea and triple super phosphate (TSP) were used in varying amounts in all sites, with urea being employed in greater quantities than TSP (Table 1). In Paikgacha, the average application of urea was nearly double (14.84 kg/ha) that of TSP (7.53 kg/ha). Cow dung was the most widely used organic fertiliser, despite having a considerably lower nutritional content than inorganic fertilisers and being applied in greater quantities. Paikgacha farmers used a massive amount of cow dung (987.19 kg/ha) in comparison to farmers in the other regions. The usage of varying amounts of fertiliser was not considered to have an effect on the grade of shrimp produced. Following the preparation, shrimp farms under various ownerships were found to stock a varied number of PL. It was discovered that smaller farms stocked more than larger ones. Individual shrimp farmers preferred 19,500 PL per hectare over group shrimp producers' 17,000 PL per hectare. On average, the farmers stocked 2 PL/m. Farmers in all categories practised shrimp fry stocking in their ponds more than five times and harvested multiple times throughout their farming calendar.

Quality evaluation in grow-out farms
All farms were situated on agricultural land and drew water from nearby rivers. Seven farms were discovered using water from a nearby shrimp farm. Shrimp farms take in water from and discharge their effluent into the same water source without treatment.
Because of the unplanned development of inlet and outlet canals, effluent water released from one shrimp farm was often frequently transported to the next farm. Farmers in the surveyed areas stocked 85-90% PL from hatchery sources, with the remaining 10 to 15% PL obtained from natural sources, despite a government prohibition on wild shrimp PL collecting.
While 13 (8.6%) of the farms in the study had a refractometer and 32 (21.33%) had pH metres, the majority (97%) did not assess the quality of water in the grow-out pond, and just 3% evaluate water quality at 3-month intervals. Secchi disks were used by 16 (10.66%) farmers, primarily in Dacope. When confronted with severe diseases in their farmed shrimp, just two (1.33%) of the farmers sent farm water to a private laboratory.
During the culture stage, farmers monitored a few quality attributes of shrimp development. The vast majority (97.5%) examined for size, colour, and disease (spot on the shell and soft shell). However, 125 (83.3%) farmers performed a visual inspection before harvesting. Farmers in Chokoria were more aware of the importance of inspecting quality attributes before harvesting than farmers in Dacope and Paikgacha (Fig. 3). In general, the majority of the farmers checked diseases and growth (size and weight relative to age) characteristics.

Occurrence and management of diseases
Until 1994, shrimp culture enjoyed a period of high production and export. Because of severe disease outbreaks that affected both semi-intensive and extensive production Fig. 3 Quality attributes evaluated before harvesting by locations systems, the sector's excellent profits eventually decreased. Shrimp diseases have been occurring on a regular basis since 1994 and are currently endemic to the areas surveyed. According to the farmers surveyed, they have been dealing with shrimp diseases since 2003, with varied circumstances differing by location. As a result, the majority of farmers in Chokoria reported the white spot syndrome virus (WSSV) disease, whereas farmers in Dacope reported red-headed colour and softshell. A few farmers in Paikgacha said that tail rot disease affects 15-20 gm shrimp the most, whereas finfish are unaffected.
Farmers claimed that they did not use pesticides or antibiotics, although anecdotal evidence showed that they did, either intentionally or unintentionally during disease outbreaks. When disease struck their farms or those of their neighbours, the farmers harvested early as well. During tidal fluctuation, lime was used and water was exchanged.

Procedures for harvesting and post-harvesting and quality management
Harvesting was carried out after 90 to 120 days of growth in general and in all of the surveyed locations, and it generally happened during the full and new moons of a lunar cycle. A cycle lasted between 5 and 7 days and drained farm water into adjacent canals. The farm was then supplied with fresh tidal water from the canal. Shrimp were attracted to the tidal water because they preferred swimming against the current, and shrimp were collected using traps and nets in a catchment area. Harvesting tools such as bamboo traps, cast nets, and seine nets were cleaned with untreated rivers or other water. Post-harvest operations included washing shrimp, checking for disease, weighing, and holding shrimp in containers ready for sale. Harvesting was accomplished by either gravity or pumping the enclosure, hand-picking, and trapping. This process took 10 to 12 h, and there was a risk of shrimp deterioration during that period. Harvested shrimp were stored in bamboo or plastic crates or coops before being cleaned and put in heaps ready for sale at the farm entrance.

Icing on harvested shrimp
The majority of Paikgacha (96%) and Dacope (90%) farmers did not use ice for the harvested shrimp, but 98% of Chokoria farmers used some ice. Shrimp in Paikgacha and Dacope were especially exposed to the ambient temperature, and they were sold in unsanitary and sanitary circumstances. In Chokoria, 48 (82%) of farmers used ice for 1 to 5 h, while 2 (16%) farmers kept shrimp on ice for 6 to 10 h (Fig. 4). Ice was obtained in all three locations, and farmers did no quality checks to guarantee the ice was not tainted.
Shrimp were sold either through negotiation with individual buyers or by auction. As a show of goodwill, some winning buyers occasionally shared their purchases with other bidders. Purchased shrimp were then transported to the nearest small or big depots by forias on bicycles, vans, trawlers, and motorbikes. The forias, for the most part, did not supply their own ice because they believed that adding ice would give them a weight advantage. Farmers and forias in Paikgacha and Dacope did not keep the shrimp on ice until they were delivered to the depots. Following the sale, the head-on shrimp were transported to the local depot, where they were chilled and delivered to the processing facility.
In addition to the failure in Paikgacha and Dacope to use ice after harvesting and onward transportation by the buyer, the quality and quantity of ice used in all three locations were frequently insufficient.

Quality concerns of the harvested shrimp
Damage to harvested shrimp included spots, damaged portions, illness, fragile shells, and accidental debris. Farmers adopted a variety of precautions to reduce such losses. 43.3% dumped them on open ground when they noticed a black spot. Soft-shelled shrimp were cooked on the farm or carried home by the farmworkers. If dirt or other foreign material was discovered, 88.7% of farmers cleaned and sold the afflicted shrimp. Table 2 outlines the steps taken by the majority of shrimp farmers to reduce quality and quantity losses.

Discussion
In the current study, the survival rate of shrimp PL differed by category, resulting in a loss of 70-90% of post-stock shrimp due to disease-related mortality. With an average yield of 100-200 kg/ha, extensive culture systems dominated brackish water shrimp farming in the investigated region (Alam and Phillips 2004). Old farms, insufficient water exchange, shallow water, utilising poor quality water, salinity variations, unstable soils and water parameters, lack of quality post larvae, and competition by non-target species in shrimp farms  were amongst the other variables impacting shrimp output (Alam 2007;2004). Using good quality PL and external usage of pond preparation reagents and feeding regime, water management, and harvesting techniques affected the survival and quality of shrimp during grow-out phase. The quality of the harvested products was also impacted by post-harvest practices such as processing, placing, and icing. Shrimp growers have been progressively using hatchery PL since the prohibition on wild PL collecting in 2000. Hatchery PL, on the other hand, is portrayed as a disease risk from unscreened and untested hatchery stock that could not be traced back to the hatchery of origin. Post larvae were the single most expensive item, accounting for more than 40% of overall expenditures. Farmers bought PL from fry dealers. The quality of PL has a major influence on a shrimp farm's productivity and revenue. Farmers chose high-quality PL between the ages of PL 15 and PL 25 to ensure a fruitful harvest (Alam 2010). Stocking more matured PL may increase survival because they acquire better disease resistance, display more robust benthic feeding behaviour, and are less vulnerable to predators. In practise, farmers continued to harvest wild PL because they believed it was stronger, more easily accessible, and more suited to local water conditions than hatchery PL.
Farmers raised serious concerns regarding the quality of hatchery PL, claiming that hatchery PL was more susceptible to disease than wild PL. First, they believed that hatcheries used chemicals or antibiotics to produce PL, leading to increased mortality rates when the fry were released into the farms. Second, they were concerned that fry agents were selling them underage PL (below PL 15 ), which resulted in greater mortality rates. Finally, they claimed that hatcheries failed to follow correct procedures for ensuring sufficient salinity acclimatisation during PL packing. Farmers also said that PL agents had misled them in the past by claiming to deliver quality PL that had been tested by a PCR machine. Farmers did not examine whether the PL they were given originated from a hatchery that used PCR equipment. Farmers were given PL packets that were unlabelled, leaving them without complete information on PL age, salinity, the amount of PL in each pack, and other stocking requirements.
It has been demonstrated that shrimp farmers used a variety of substances such as lime, fertilisers, and chemicals to improve soil and water quality and control biological problems such as phytoplankton blooms, aquatic plant infestations, disease vectors, wild fish proliferation, and the influence of production efficiency (Boyd and Tucker 1998). Shrimp growers were typically aware of the risks of working with pesticides. Nonetheless, they were less concerned about the possible influence of pond management chemicals on the surrounding ecosystem and the quality of aquatic food supplies (Boyd and Massaut 1999).
Shrimp producers in the studied locations usually followed the criteria outlined in national regulations. Thus, the preparation of the farms began with ploughing the enclosed land and drying it in the sun for approximately a week. Afterward, organic and inorganic fertilisers were applied, followed by lime (CaCO3). After 1 week of fertilising, water was introduced into the ponds. Chemicals or antibiotics were not used on any of the farms surveyed. In most cases, the observed differences (lime, organic and inorganic fertiliser application rates) in the studied areas were lower than Alam's (2007) findings from a study of other shrimp areas in the southwest region of Bangladesh. Only frequent liming of the ponds as a disease control strategy was used in the other forms of post stocking management.
When pond effluents are discharged into bodies of water, fertilisers enhance nutrient concentrations in the water and produce nutrient enrichment. According to Boyd and Massaut (1999), if a few days pass between fertiliser application and water discharge, the majority of fertiliser nutrients are absorbed by pond organisms or sediments or are lost to the atmosphere via denitrification or ammonia volatilisation. According to Schwartz and Boyd (1994), ponds are highly effective in assimilating nutrients in a few weeks. All shrimp producers in the study area were observed to maintain a few-day gap between input applications, permitting the discharge of used water into the ecosystem. Other studies of the Bangladesh shrimp farm sector (Alam et al. 2005a, b;Wahab et al. 2003) found that waste generation and contamination were insufficient as a result of the use of inputs in extensive shrimp farming and that culture practices worked as a sink for sediments and nutrients in the water. According to Boyd and Massaut (1999), none of the liming agents and fertilisers employed in the extensive shrimp production system poses a food safety risk.
Several sanitary issues were discovered in the shrimp icing processes. Thus, following washing, collected shrimp were placed in baskets or on the floor under the sun with little or no ice in the majority of the farms examined. While farmers expressed a desire to use ice to prevent deterioration, depot owners and their representatives advised them not to do so since it may increase shrimp weight. This practice resulted in shrimp producers failing to satisfy internationally approved icing requirements. Freezing fish and crustaceans is one of the easiest and most effective techniques to prevent spoiling and increase shelf life (Huss 1995). The longer the duration before ice and the higher the exposure to ambient temperatures resulted in increased bacterial activity in shrimp muscles (Alam et al. 2005a, b;Ganesan et al. 2005), whereas delayed icing after harvest resulted in a loss in fish and shrimp shelf life (Huss 1995).

Conclusions
Shrimp growers benefitted from certain unique natural features, such as extensive areas of low-lying tidal land that allow for water circulation via natural tidal variations. Production was proven to be extensively modified, giving Bangladesh a competitive advantage through shrimp marketing that was as natural and tastier than shrimp produced under more intensive production methods. However, because of the extensive production system, they were unable to raise their revenue through increased output unless they acquired more land for shrimp farming. Farmers, for the most part, did not use pesticides or synthetic feed. Shrimp producers increased their quality standards by using plastic crates to carry shrimp, improving working surfaces for washing, sorting, and selling harvested shrimp, and building more hygienic restrooms a safe distance from farms.
It was also shown that farmers were unsatisfied with the quality of hatchery PL. They had a greater mortality rate and were marketed in packets without the necessary information on salinity, number, and size. Farmers also lacked scientific information about assessing PL and shrimp quality on their farms, putting the stock at risk of disease. It was discovered that shrimp were exposed to ambient temperatures of the sun after harvesting, and farmers frequently abstained from icing them at the request of the next buyers (forias or depots). The latter viewed icing as boosting shrimp weight and hence purchasing costs.
Funding Open Access funding enabled and organized by CAUL and its Member Institutions Commonwealth of Australia through the Endeavour International Postgraduate Research Scholarship and a Curtin University Postgraduate Scholarship.

Data availability
The researcher agreed to secure storage of research related records and data for a period of five years and that access to these records and data were to be restricted to the researcher.
Code availability Not applicable.

Declarations
Ethics approval and consent to participate Approval for the research was granted by the Ethical Committee of the Graduate Studies Office of Curtin University, Australia. The research dealt with data and information related to the activities of shrimp farms. Thereby issues of informed consent, confidentiality, anonymity, and voluntarism were engaged throughout the research. Informed consent remained a priority throughout the research. Participants were assured that the information they provided would be used for academic purposes and that the results of the research would be used in writing a PhD thesis and later published in scholarly and peer-reviewed international journals. When interviewing illiterate respondents, extra efforts were made to explain the purpose of the study and that any information provided would be anonymous.

Conflict of interest The author declares no competing interests.
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