The government and non-government organizations must come forward to raise public awareness and the provision of safe drinking water to the coastal communities.An alternative measure of living standards and profitability of the shrimp farming practices was comparing the farming communities household construction materials in coastal areas.The results divulged that before shrimp farming, about 82 % of the households’ wall construction material was mud that dropped to 58 % after shrimp farming.The floor construction was predominately made by mud before shrimp farming that dropped to 78 % after shrimp farming, while the use of bricks in floor construction increased from 8% to 22 %.The use of tin for roof construction increased from 26 % to 66 % before and after shrimp farming, respectively.Instead of capture fisheries, shrimp farming brought significant improvements in the housing construction quality.Over 80 % of hut-like households were reported by Islam et al., which indicated a declining tendency after shrimp farming.The study made it feasible to conclude that shrimp farming has resulted in a substantial uplift of the residents living and housing pattern.Based on previous reports, higher salinity levels in the study area changed the soil quality that turned it unfit to build the house with a simultaneous decline in rice cultivation, causing an immense lack of straw for roof construction.Formerly a rice agriculture hub, this study’s coastal areas displayed a substantial shift from rice culture to shrimp farming.We intended to reveal the hidden reasons for this blue revolution, and the data showed that over a half of the farmers citing the prevailing salinity as the leading reason for this shift from agriculture to shrimp farming.Apart from this, we also looked for other reasons compounding the impact of increasing salinity,flood and drain table and the results showed that salinity and poor rice production , salinity and more income while only 10 % of farmers established the reason for poor rice production.
Akber et al.have reported similar findings in previous studies targeting the same locality.The substantial economic benefit is the primary reason for the increased commercial saline-water Bagda shrimp farming.The saltwater ascension worked as a double-edged sword.It resulted in a decline in rice production while acting as a more profitable farming source for the coastal communities.The saline water intrusion was the prime cause that forced the study area people to shrimp farming instead of rice cultivation.With declining land for grazing and fodder cultivation, shrimp farming has brought overwhelming changes in the patterns of livestock and poultry rearing as well as in the tree production in the coastal areas in Bangladesh.After shrimp farming, the number of people having no cows and goats increased from 14 % to 68 % and 10%– 40%, respectively.It indicated a tremendous decline in cows and goats rearing practices in the study area.On the other hand, where small or livestock raising for personal usage declined, the commercial level farming of cows and goats increased before shrimp farming times.This massive revolution in livestock rearing practices alluded to the potential economic solvency.The number of trees is also considered as wealth that can be utilized in times of emergency.The presence and rearing of trees and poultry birds displayed substantial decline after shrimp farming, and the reason is apparent.The trees provide home and roosting sites to predatory birds, while poultry farming could not have been profitable due to changing climatic conditions and saltwater intrusion.Further, increasing salinity levels could have compromised the suitability of soils to grow trees and seedlings.Previous studies have reported that shrimp farming decreases tree production , especially for more profitable management, i.e., expanding shrimp farms.
Sustainable income brings satisfaction among the farming communities.The percentage of farmers with lower income was higher, having income ranges lower than USD 51–100.It was noticed that the rate of shrimp farmers having an income range of USD 101–150 jumped from 16 % to 36 % after shrimp farming practices.The farmers having more than 150 USD income were only 2%, which soared to 26 % after shrimp farming.It alluded to the sustainable increase in the income levels of the coastal shrimp farming communities.With our findings, we are correct to say that shrimp farming has become a new lucrative business for the southwest coastal inhabitants rather than rice cultivation.The rice and shrimp culture’s annual comparative cost and income are shown in supplementary material Table 4.We also collected the cultivable land prices in the rice and shrimp culture, and findings are presented in supplementary material also.Shrimp farming has brought a significant change in the stakeholders income level.Approximately 72 % have shown absolute satisfaction after shrimp farming, while 4% expressed as very satisfied.However, a 16 % remained neutral with neither satisfied nor dissatisfied, while only 8% showed dissatisfaction after shrimp farming.Previously, all the respondents have expressed their satisfaction status regarding shrimp farming comparing with rice cultivation as previous research.The farmers expressed their opinion based on their present social-economic status and life patterns that may lead to environmental consequences.Those show exhibited satisfaction indicated said that the infrastructure quality of locality is more developed than before.They were able to maintain a family at a medium level and send their children to school.They expressed shrimp farming aided in an increased purchasing power.Some others opined though shrimp farming has benefitted them economically, it leads them to buy all of the commodities they had to cultivate before.Therefore, we can conclude that shrimp farming has become beneficial to the study area as many respondents are satisfied.
In the wake of shrimp farming, an enormous increase has come in the respondents income level compared to rice cultivation.In some cases, it has shown manifolds increase.Nevertheless, the respondents also mentioned that when their gherinfected by viral diseases, it critically affected their earning in huge investments.So, this can be concluded as that shrimp farming’s income could be unpredictable, which is similar to previous studies.This also provides a reasonable explanation for the dissatisfaction among some of the shrimp farmers.We studied the change in income status of the shrimp farming communities after shrimp farming, and the results showed that shrimp farming brought conspicuous changes in the income status.The primary occupations included agriculture shop keeping, labor , fishing, salaried individuals, and private business.The total percentages showed that income levels disclosed a marked increase in the range of 101–150 USD.The income ranges of 51–100 USD and >150 USD obtained a 26 % increase, which can be described as a marvelous improvement in the shrimp farming communities economic status in the coastal areas of Bangladesh.These findings indicated that shrimp farming increased the people’s income in a reasonable way that could be projected to the elevated social-economic status of the coastal communities.We studied the positive and negative impacts of shrimp farming on a scale of 1− 10.The results displayed that the most positive impact was the high profitable business compared to the rice cultivation.In contrast, the highest negative impact was the lack of fodder for livestock.The respondents firmly supported that shrimp farming is more profitable than rice cultivation.Many others believed that due to increasing shrimp farming, there was higher daily demand for fish, increased land value, and increased daily income.However, some mentioned that daily income from the gher is somewhat dependent on other factors as well.The last one among the positive impacts is that shrimp farming required less labour than rice cultivation.Many believed that shrimp farming takes more time than rice cultivation; there is no strenuous effort.All types of impacts are countable and help identify the fundamental problems of shrimp farming.After the lack of fodder availability, 7.44 out of 10 were mindful of destroying vegetation and its effect on bathing or drinking water.Some respondents poorly ranked the lack of employment opportunities due to shrimp farming.
Rearing livestock and cultivation of the homestead garden is an integrated part for the rural households.Nevertheless, saline water intrusion has supplanted the grazing land, which hampered the cattle rearing.We also investigated the overall impacts of shrimp farming perceived by the shrimp farming communities in Bangladesh’s coastal communities.The survey was based on four preordained factors used to assess the respondents overall perception of shrimp farming.The elements used for comparing were rice cultivation, fish culture, salinity, and shrimp fry collection.The participants were asked to express their opinion in five categories: strongly agreed, agree, neither agree nor disagree, disagree, strongly disagree, and these were weighted by 5, 4, 3, 2, 1, respectively.The 78 % of participants strongly agreed that shrimp farming is more profitable than rice culture, while 60 % agreed on its higher profitability than freshwater fish culture.However, 46.9 % agreed that it was easy to enter the saline waters for shrimp farming, while 44 % agreed that it was easy to collect the shrimp fry.Using the weighted index method, the total scores were 237, 214, 188, and 162, respectively, rolling bench for the stated four factors.The highest total score was 237 for more profitable than rice culture, followed by 214 for more profitable than freshwater aquaculture.These findings indicated shrimp farming as a more profitable practice than rice cultivation with other supporting factors.Aquaculture, a vital economic activity, contributes significantly to global nutrition and food security, whose production peaked at 82.1 million tons and sale value was estimated at USD 250 billion in 2018.China is the country with the largest aquaculture producer in the world, accounting for around 58 % of total global aquaculture production, far exceeding the total output of the second- and third-ranked countries combined, of which Pacific white shrimp occupies an economically important position in aquaculture.However, several emerging pathogens, including covert mortality nodavirus , Vibrio causing acute hepatopancreatic necrosis disease , and shrimp hemocyte iridescent virus , etc.have posed many great challenges on the global shrimp farming industry.In the second half of 2020, unusual mortality events of cultured P.vannamei occurred in local farms in Dongying City and Weifang City, China, some diseased shrimp showed symptoms of hepatopancreatic atrophy, midgut empty and shell softening.In this report, we analyzed and detected the pathogens that could be infected by the diseased shrimp and its feed organisms, verified through histology and molecular biology methods, and finally determined the cause of outbreak death of farming shrimp.
At the end of 2020, continual mortality of cultured P.vannamei generally occurred in local farms in Dongying and Weifang City, China.Over 80 % of local shrimp farms have been impacted.In Dec 2020, the author’s laboratory was asked to perform a local investigation into some shrimp farms breeding white leg shrimp.Four indoor semi-intensive aquaculture farms were visited.It is understood that greenhouse aquaculture is one of the important local aquaculture modes, and underground brine is an important source of water for aquaculture due to the northern part of the city is located in the coastal area.The aquaculture water was aerated with air stone, the water temperature was 28–30 ◦C, and the salinity was 18–25 ‰.During the breeding period, the shrimps were fed with mixed bait and frozen bait.The morbidity of shrimp was characterized by continual death.The onset time mainly occurred in the two stages of shrimp larvae population separating and shrimp juvenile population separating.The final density was 500–1000 individuals/m2 after the shrimp larvae population separated.Mortality would be observed to start 3–7 days post-transfer.At the beginning of the disease , the number of shrimp deaths was small, but the number of shrimp death reached 100–150 individuals/pond after 7 days.Shrimp death continued, with the high number of dead shrimps exceeded 150 kg/pond 3 days after the onset of illness in some adult shrimp farms.The diseased individual of the P.vannamei showed obvious clinical symptoms, including hepatopancreatic atrophy with color fading, empty stomach and guts, shell softening.Mild muscle whitening and necrosis occurred in most P.vannamei individuals in the VCMD case, and a few diseased individuals that being at the acute stage showed obvious large proportion whiteness of abdominal segment muscle.Meanwhile, the diseased shrimp was weak in vitality and usually sunk to the bottom of the pond without moving.What’s more, shrimp grew slowly on some farms.All samples were amplified and prepared for sequencing using a two step, reverse transcription nested polymerase chain reaction protocol with two pairs of primers.The procedures and primers used were identical to those described as reported previously.Following amplifications, products were separated in an agarose gel electrophoresis and bands were sequence verified at Sangon Biotech Co., Ltd.The sequence was identified through BLAST searches, and the deduced amino acid sequences of CMNV target RdRp gene fragments from positive samples and RdRp amino acid sequences from other nodavirus were selected for phylogenetic analysis by using MEGA X software.