Local Fish Farm Research Articles

Market choice behavior of fish farmers in the haor regions of Bangladesh

The fish farming sector in haor regions of Bangladesh is integral to both local livelihoods and the national economy. This study examined the factors that influence fish farmers’ choice of market in this region, offering empirical insights into their decision-making processes. Using a random sampling technique, data were collected from 450 fish farmers across three upazilas in Netrokona, Kishoreganj, and Sunamganj districts. The multinomial logit model was employed to identify these influencing factors. The analysis revealed that factors such as age, education, access to extension services, and labor availability have negative effects on the selection of secondary markets. Total market loss also negatively impacts the choice of both secondary and tertiary markets. Furthermore, transportation facilities and distance to the market decrease the probability of selecting tertiary markets. In contrast, access to credit facilities positively influences the choice of secondary markets and negatively influences the choice of tertiary markets. Infrastructure facilities have a positive impact on the choice of secondary and tertiary markets but reduce the likelihood of selecting primary markets. This study underscores the importance of effective support systems, investments in education and infrastructure, risk management enhancements, and the promotion of sustainable practices in the local fish farming industry. Policymakers and stakeholders should consider these findings when developing strategies for the sustainable growth of the haor regions’ fish farming sector. Ann. Bangladesh Agric. (2023) 27 (2): 71-89

Isolation and identification of vapA-absent Aeromonas salmonicida in diseased snakehead Channa argus in China.

Aeromonas salmonicida is the typical pathogen causing furunculosis, reported widely in salmonids. Because of multiple serotypes, the control of A. salmonicida-caused disease has increasingly received much attention. Recently, A. salmonicida infection was reported in non-salmonid fish species. Here, a pathogenic A. salmonicida, named as As-s, was isolated from cultured snakehead (Channa argus) in a local fish farm in Shandong, China. As-s displayed clear hemolysis, amylase, and positive catalase activities, and grew at a wide range of temperatures (10-37 °C) and pH values (5.5-8.5). As-s was highly sensitive to cefuroxime sodium, ceftriaxone, ceftazidime, piperacillin, and cefoperazone and also apparently sensitive to chloramphenicol, erythromycin, and 25% cinnamaldehyde. The Virulence array protein gene cloning' results suggested that As-s has this gene compared with the other two vapA-containing strains, despite a close relationship of these strains via phylogenetic analysis. Severe ulcers on skin, muscle, and abnormal liver, and hemorrhage in pectoral/ventral fins and anal region were observed, and exophthalmos were also noticed in infected juvenile snakehead, as well as necrosis and infiltration of blood cells emerged in the internal organs using pathological section. In addition, As-s caused high mortality in snakehead, consistently with its immune gene response. This study reports the first isolation of vapA-absent A. salmonicida in snakehead.

ASSESSING FISHING ACTIVITY, FISH PRODUCTION AND DEMAND IN ILU ABBA BORA ZONE, SOUTHWEST ETHIOPIA

The study was aimed to assess fishing activity, fish production and demand outlook in Ilu Abba Bora Zone, Oromia Region, southwest Ethiopia, to generate baseline data that would help in the proper and sustainable utilization of fish resources. Previous reports, field assessment, structured and semi-structured questionnaires and direct observation were employed for data collection. Five districts (Mettu, Yayo, BiloNopa, Bure and Sale Nono) were selected using purposive sampling technique. From each district, fishermen and households along and near riverine water bodies were selected purposively. The fishing activities of the area are aimed for subsistence by part-time fishermen and for local market during the dry season. The fishing gear commonly used are hooks of different sizes, traps (fish basket) and rarely gillnet. Birbira (Milletia ferruginea) is also used by fishermen in Sale Nono district. Though the severity of the constraints varies from one district to the other, the main fish production constraints in the area are low demand for fish, lack of awareness, lack of facilities, low profit, and long distance to market place. The fish demand and supply in the study area is unbalanced. Fresh whole fish, gutted and dried fish are mostly preferred fish products. Labeobarbus intermedius, Labeobarbus nedgia, Bagrus docmak and Oreochromis niloticus are the species preferred by consumers in the study area. Awareness creation and promotion of local fish farming is important to integrate fish in the community’s diet and to scale up fish demand and supply in the area.

Farmed Fish Market in Svay Rieng Town, Svay Rieng Province

The fisheries sector in Cambodia plays an important role in the economic, security, food, and nutrition sectors, including freshwater, seawater, and aquaculture. This study aims to 1) understand the type and size of farmed fish in Svay Rieng town, 2) understand the farmed fish market chain in Svay Rieng town, and 3) analyze the economic efficiency of selling farmed fish in Svay Rieng town. As a method, a survey was conducted by selecting 40 samples (fish vendors) from Veal Yun Market and Rong Bonler Market in Svay Rieng town by face-to-face interviewing. The results found that the activities of selling and consumption of farmed fish in the market are very active. Fish vendors sold many types of farmed fish. The fish types that the vendors sell the most are channa striata, clarias macrocephalus, channa micropeltes, red tilapia, pantius gorionothus, puntioplites, and other types. The fish market chain in Svay Rieng town is traded and trafficked from brokers to traders and fish vendors in the market and resold to wholesalers, retailers, and consumers. For the economic efficiency analysis of farmed fish sales in Svay Rieng town, there is a majority of vendors who are prosperous. To encourage local fish farming, the government should step up its efforts to support farmers who raise fish as a family and those who depend on fishing for their livelihood by educating and training them to cut back on imports.

Effect of Chlorpyrifos on Histology of Liver, Gills, and Brain of Oreochromis Mossambicus (Peters)

Most of the river waters in Kerala are found to have several pollutants such as heavy metals, plasticizers, and pesticides. Chlorpyrifos, commonly known as Dursban is a broad-spectrum organophosphate insecticide widely used in Kerala to control insects in crops, termites and to control mosquito larvae. This pesticide is known to reach the aquatic ecosystem causing several damages to aquatic organisms. Fish being on top of the food chain bioaccumulation of these pesticide residues are of concern. This study was to find the histological changes in the liver, brain, and gills of Orechromis mossambicus, commonly called Tilapia, a common freshwater edible fish, on exposure to chlorpyrifos for 7, 14, and 21 days to evaluate the extent of toxicity. For this fish, Orechromis mossambicus of age one to three were procured from a local fish farm of Pathanamthitta district, Kerala, and were acclimatized in tanks in the laboratory and exposed to chlorpyrifos for 7, 14, and 21 days and histology of brain, liver, and gills were carried. The microphotographs of the sections show severe damage to these tissues as early as 14 days of exposure.

Tracking Microbial Diversity and Hygienic-Sanitary Status during Processing of Farmed Rainbow Trout (Oncorhynchus mykiss).

Aquaculture is becoming a strategic sector for many national economies to supply the increasing demand for fish from consumers. Fish culture conditions and processing operations can lead to an increase in microbial contamination of farmed fish that may shorten the shelf-life of fish products and byproducts, and ready-to-eat fishery products. The objective of this study was to evaluate the hygienic-sanitary status of water, environment, and processing of fresh-farmed rainbow trout (Oncorhynchus mykiss) fillets produced in a local fish farm in Andalusia, Spain. To achieve this, a longitudinal study was carried out by collecting environmental (air and food-contact surfaces), water from fish ponds, and rainbow trout samples. Thereby, seven sampling visits were performed between February 2021 and July 2022, where foodborne pathogens and spoilage microorganisms, together with physicochemical parameters, were analysed in the collected samples. Further, microbial identification of microbiota was achieved through a culture-dependent technique using blast analysis of 16S RNA gene sequencing. The results showed that Listeria monocytogenes and Salmonella were not detected in the analysed samples. Regarding the hygienic-sanitary status of the fish farm, the slaughtering bath, the eviscerating machine and the outlet water from fish ponds presented the highest counts of coliforms, Enterobacteriaceae, and Aerobic Mesophilic Bacteria. Staphylococcus aureus and sulphite-reducing Clostridium were identified in the conveyor belts, fish flesh, and viscera. The 16S RNA identification confirmed the presence of viable spoilage bacteria such as Citrobacter gillenii, Macrococcus caseolyticus, Hafnia paralvei, Lactococcus lactis, Lactococcus cremoris, Klebsiella, Escherichia coli, Morganella morganii, and Shewanella. Three of these genera (Citrobacter, Hafnia, and Pseudomonas) were present in all types of samples analysed. The results evidenced potential transmission of microbial contamination from contaminated packaging belts and boxes, evisceration and filleting machines to flesh and viscera samples, thus the establishment of control measures should be implemented in fish farm facilities to extend the shelf-life of farmed fishery products.

Alterações na motilidade espermática do peixe amazônico Tambaqui Colossoma macropomum (Cuvier 1816) (Characiformes: Serrasalmidae) exposto a dois pesticidas

Abstract The great biodiversity of neotropical fish species that have external fertilization as a reproductive strategy, like the tambaqui, requires more careful analyzes in toxicological tests of the various pesticides implemented in Brazilian agriculture over the last few years. In this context, the objective of the present work was to evaluate possible sperm alterations in tambaqui (Colossoma macropomum) semen exposed to two different pesticide residues. Seminal samples of sexually mature tambaqui males from a local fish farm were used. Semen was collected eight hours after hormone induction into graduated glass tubes. After initial assessment of the lack of prior activation, the experiment was carried out in a factorial scheme, testing two pesticides widely used in agricultural systems (glyphosate and fenitrothion). For each pesticide, five concentrations were tested (6, 12, 24, 120 and 240 mg/L), with motility analysis at times 0, 30 and 60 seconds after activation. As a control, activation with 0.9% NaCl solution and motility analysis at the same times described for pesticides were used. Results indicate that in natura samples exhibited initial motility of 89.2 ± 4.9% and mean duration of 100 seconds (up to 10% sperm motility). The reduction in sperm motility occurred significantly (p < 0.05) after 30 seconds in all concentrations tested, except for the concentration of 240 mg/L because no activation was observed. The tests described here demonstrate that tambaqui semen was sensitive to the process of exposure to pesticide residues, and can be used in biomonitoring analyzes of the aforementioned agricultural pesticides.

Establishment of Local Fish Farm “La’ Prestige Agro” LLC in Nigeria

This project aims to create a unique and most efficient large-scale farming of freshwater fish for daily consumption in Nigeria. According to the CGIAR African Fish Research Program 2019. Nigeria has one of the highest levels of fish consumption in Africa. In Nigeria, Africa's most populous country, fish is an important part of the household diet. Fish makes up about 40% of the protein consumed in the country, with fish consumption at 13.3 kg per person per year [17]. According 2021 Fish Information and Services report, Nigeria spends 250 billion naira approximately (US$560 million) annually on fish importation [6, 7]. The mainly import fish from Japan, Norway, Russia, United States and Netherlands. Nigerian’s population fish demand is approximately 3.3 million metric tons but the country is only able to produce 1.1 million metric tons locally. With a report on this study and as a Nigerian citizen who has lived in Nigeria and has a family living there, with current updates on the Nigerian fish market and its economic status. It is estimated that Nigeria lacks 60 percent of the fish production capacity equivalent to the country's fish consumption needs. Thus, investing in fish production in Nigeria is profitable and comes with the least investment risk of bankruptcy as consumers are always available to buy once you have a successful production [8, 9]. Thus, our company has enough market space and high demand for fish to succeed in the Nigerian fish market. This will allow our company to earn enough profit to repay the investment loan and interest on it within the agreed time frame agreed with our investors.

Antibacterial effects of peracetic acid disinfection assessed by culturability, enzyme activity and flow cytometry

Aquaculture water disinfection with around 1 mg/L peracetic acid (PAA) was proved in various studies to effectively impair microbial proliferation and reduce pathogen-caused fish mortality. In the present study, we monitored the antibacterial effect of biweekly water disinfection with 1 mg/L PAA at a local flow-through fish farm for 8 weeks. Results from replicate water samples showed inconsistency of antibacterial efficacy assessed with colony forming units (CFU) of total culturable bacteria and a commercial enzyme activity assay. Single PAA disinfection caused up to 90% reduction of CFU in water. In contrast, the microbial hydrolase activity was hardly affected or even enhanced. Both methods have limitations and can't truly represent viable bacteria. We further monitored the temporal response of two Yersinia ruckeri isolates in suspensions to single PAA disinfection via high-throughput flow cytometry. We found out that the bacterial cell membrane damage appeared not instantly but with a lag phase of at least 2 h post disinfection at 4 °C. The abundance of cell membrane damage, considered as cumulative bacterial mortality, kept rising and maximized at 48 h post disinfection. The survived cells were more likely to enter the viable but non-culturable (VBNC) state at higher PAA concentrations. One isolate was more prone to enter the VBNC state than the other. Neither Y. ruckeri isolate showed measurable reaction with the enzyme substrate of the commercial microbial hydrolase activity assay. Our findings refresh knowledge about the dynamics of bacterial cell mortality post PAA disinfection (probably also similar non-thermal disinfection methods). Aquaculture practice should be aware of the delayed disinfection outcomes and pay attention to the dominance of VBNC state.

Complete Genome and Molecular Characterization of a New Cyprinid Herpesvirus 2 (CyHV-2) SH-01 Strain Isolated from Cultured Crucian Carp.

Cyprinid herpesvirus 2 (CyHV-2) is a causative factor of herpesviral hematopoietic necrosis (HVHN) in farmed crucian carp (Carassius carassius) and goldfish (Carassius auratus). In this study, we analyzed the genomic characteristics of a new strain, CyHV-2 SH-01, isolated during outbreaks in crucian carp at a local fish farm near Shanghai, China. CyHV-2 SH-01 exhibited a high sensitivity to goldfish and crucian carp in our previous research. The complete genome of SH-01 is 290,428 bp with 154 potential open reading frames (ORFs) and terminal repeat (TR) regions at both ends. Compared to the sequenced genomes of other CyHVs, Carassius auratus herpesvirus (CaHV) and Anguillid herpesvirus 1 (AngHV-1), several variations were found in SH-01, including nucleotide mutations, deletions, and insertions, as well as gene duplications, rearrangements, and horizontal transfers. Overall, the genome of SH-01 shares 99.60% of its identity with that of ST-J1. Genomic collinearity analysis showed that SH-01 has a high degree of collinearity with another three CyHV-2 isolates, and it is generally closely related to CaHV, CyHV-1, and CyHV-3, although it contains many differences in locally collinear blocks (LCBs). The lowest degree of collinearity was found with AngHV-1, despite some homologous LCBs, indicating that they are evolutionarily the most distantly related. The results provide new clues to better understand the CyHV-2 genome through sequencing and sequence mining.

ISOLATION AND IDENTIFICATION OF POTENTIAL PATHOGENIC BACTERIA IN CARP (Cyprinus carpio LINNAEUS, 1758) CULTURED IN FISH FARMS, KASHMIR

The purpose of this research was to find out if there were any possibly disease-causing bacteria in carp cultured in Central and South Kashmir, as well as to find what species they were. Fish samples were taken from different local fish farms of the Srinagar and Anantnag districts. Once a week, three fish samples were collected from each farm and repeated three times. Bacteria were found in the fish's mucous membranes, gills, liver, and kidneys, among other places. To determine the bacteria's species, the results of each target organ's isolation were biochemically evaluated. Potential pathogenic bacteria found in carp from this research are (21.02%) Aeromonas sp., (7.64 %), Staphylococcus sp., (3.28%) Shigella sp., (14.65%) Bacillus sp., (3.82%) Proteus sp., (1.91%) Salmonella sp., (9.55%) E. coli, (6.37%) Enterobacter sp., (8.92%) Klebsiella sp., (10.83%) Pseudomonas sp., (5.73%) Acinetobacter sp., (3.82%), Flavobacterium sp. and ,(1.91% ) Serratia sp. Based on the results of research that has been done, we observed that bacterial infections are the most prominent microbiological agents impacting cultured fish, Aeromonas sp. and Bacillus sp. were most prevalent in fish microbiota. Contamination of fish's natural environment may have an impact not only on the health of fish stocks but also on public health, as fish and fish products can be a source of human pathogens. This study offers some inputs on likely bacterial infestation of fish and fish products which can compromise public health.

Some Biological Aspects of Pond Reared Mystus cavasius (Hamilton, 1822) Collected from a Local Fish Farm in Mymensingh, Bangladesh

An investigation was conducted to observe some biological aspects including growth, sex ratio, gonadal maturity, artificial insemination, fecundity, fertilization, hatching and larval development of Mystus cavasius in a private hatchery. With the specific growth rate (SGR) of 1.80±0.53 and average daily gain (ADG) of 0.18±1.0, the total weight of the sampled fish ranged from 1.59±0.44 to 28.30±14.77 g, and the length ranged from 3.39±0.77 to 13.62±3.16 cm. There has been a strong association between fish length and weight (r2=0.95). The ratio of males to females was 1:1.58. The female and male lengths at first maturity were 9.2 and 9.6 cm, respectively. The gonadosomatic index (GSI) of females found in the present study were ranged from 4.35 to 7.44 with the mean of 6.71±0.69 during the study period. The fish is highly fecund and fecundity ranged from 5600 to 25860 with the mean of 17083±6055 for the corresponding length 15.49±1.69 cm, body weight 37.53±7.24 g and gonad weight 2.55±0.63 g. During the experiment, the fertilization, hatching rates, and larval development were observed. The scatter plot developed for the association between length and body weight, fecundity-body length, fecundity-body weight and fecundity- gonad weight implies a significant correlation both arithmetically and logarithmically.

Barramundi take the average to cope with high temperatures

Despite the guarded optimism of some politicians following the COP26 summit in November 2021, the planet continues to warm, leaving so-called cold-blooded animals (ectotherms) with an uncertain future. No one really knows how fishes will cope as their waters warm. ‘Lifetime fitness, such as growth and number of offspring produced, in ectothermic animals such as fish is thought to be maximised at some optimal temperature and to decrease either side of that optimum’, says Hanna Scheuffele from Deakin University, Australia – which would place animals at risk at temperatures that they are not prepared for. But Scheuffele and Timothy Clark, also from Deakin University, were curious to find out just how hard-wired fish physiology is – whether they can adjust their physiological performance window to cope with higher temperatures and whether the varying temperatures experienced by an animal over the course of the day could leave them less well prepared as the mercury rises? To answer these questions, the duo monitored the metabolism of a tropical fish, barramundi (Lates calcarifer), to find out how they fare over a range of temperatures.Receiving ∼450 young barramundi from a local fish farm, Scheuffele, Clark and Francesc Rubio-Gracia – visiting from the University of Girona, Spain – divided the fish into four groups held at different water temperatures: one each at 23, 29 and 35°C and the fourth on a daily temperature cycle between 23 and 35°C. ‘Juvenile barramundi are often found in highly fluctuating environments such as estuaries and coastal swamps throughout northern Australia and therefore can experience drastic daily temperature changes of ±10°C’, says Scheuffele. After allowing the fish to adjust to their new homes for 2 weeks, Scheuffele, Clark and Rubio-Gracia began the monumental task of recording the fish's resting metabolic rate, measuring how much oxygen each individual consumed while resting overnight at the temperature of their home tank, before recording their maximum metabolic rate when recovering from a chase around a pool. Then, the team altered the temperature to one of the two remaining temperatures and repeated the experiments, before selecting the third temperature and measuring the fish's resting and maximum metabolic rate again.‘We had four very busy months of measuring oxygen consumption, all the while attending to the daily needs of nearly 500 fish’, says Scheuffele, who recorded that – as expected – the fish's metabolic rates rose when they were transferred to warmer water. However, when the team checked the performance of the fish that had lived in a variable environment, cycling between 23 and 35°C each day, the fish did not struggle as they had predicted. Instead, their lifestyles were most efficient at 29°C, which was the average temperature that they had experienced each day. ‘The average daily temperature seems to be more important than the range in daily temperature when it comes to regulating aerobic performance’, says Scheuffele.In addition, instead of seeing a dip in the fish's ability to keep going at 35°C, the team recorded all of the fish rising to the challenge of increasing their maximum metabolic rate in warmer conditions, even when they were used to living at 23°C. Also, varying the temperature experienced by the fish over the course of the day did not leave them better prepared for a heatwave than the fish that had lived at constant temperature.So, when setting their metabolism, the average daily temperature that tropical barramundi experience is more important than the daily extremes they encounter, and Scheuffele is keen to find out whether the fish's responses to constant versus variable temperatures differ at the level of the tissues in their bodies.

Susceptibility of Goldfish to Cyprinid Herpesvirus 2 (CyHV-2) SH01 Isolated from Cultured Crucian Carp.

Cyprinid herpesvirus 2 (CyHV-2), a member of the Alloherpesviridae family belonging to the genus Cyprinivirus, is a fatal contagious aquatic pathogen that affects goldfish (Carassius auratus) and crucian carp (Carassius carassius). Although crucian carp and goldfish belong to the genus Carassius, it is unclear whether they are susceptible to the same CyHV-2 isolate. In addition, the origin of the crucian carp-derived CyHV-2 virus isolate remains unclear. CyHV-2 SH01 was isolated during herpesviral hematopoietic necrosis disease (HVHN) outbreaks in crucian carp at a local fish farm near Shanghai. CyHV-2 SH01 was confirmed by PCR and Western blot analysis of kidney, spleen, muscle, and blood tissue from the diseased crucian carp. Moreover, histopathological and ultra-pathological analyses revealed pathological changes characteristic of CyHV-2 SH01 infection in the tissues of the diseased crucian carp. In the present study, goldfish and crucian carp were challenged with CyHV-2 SH01 to elucidate viral virulence. We found that CyHV-2 SH01 could cause rapid and fatal disease progression in goldfish and crucian carp 24 h post-injection at 28 °C. Experimental infection of goldfish by injection indicated that the average virus titer in the kidney of the goldfish was 103.47 to 103.59 copies/mg. In addition, tissues exhibited the most prominent histopathological changes (cellular wrinkling and shrinkage, cytoplasmic vacuolation, fusion of the gill lamellae, and hepatic congestion) in CyHV-2 SH01-infected goldfish and crucian carp. Thus, crucian carp and goldfish showed a high sensitivity, with typical symptoms, to HVHN disease caused by CyHV-2 SH01.

Genetic characterisation of cercarial stages of Choanocotyle Jue Sue and Platt, 1998 (Digenea: Choanocotylidae) in a native Australian freshwater snail, Isidorella hainesii (Tryon).

Isidorella hainesii (Tryon, 1866) is a native freshwater snail, belonging to the family Planorbidae, commonly found on aquatic vegetation in south eastern parts of Australia. In the present study, we report natural infection with a species of Choanocotyle Jue Sue and Platt, 1998 (Digenea: Choanocotylidae) parasite in inland Australia for the first time, followed by characterisation of the parasite using both morphological and molecular approaches. Snails (n = 150) were collected from recently drained, natural ponds at a local fish farm located in the Riverina region, New South Wales, Australia. Parasites were subjected to preliminary morphological examination followed by DNA extraction to obtain their ITS-2, 18S and 28S sequences. Based on their sequence data and phylogenetic analyses they were identified as Choanocotyle hobbsi Platt and Tkach, 2003, which has only previously been described from Chelodina oblonga Gray, 1841 (snake-necked turtle) in Western Australia. Previous researchers suggested that in Australia, C. oblonga and its parasite fauna are separated from their eastern counterparts due to formation of impenetrable waterless desert in the country during the late Cretaceous. Our study extends the distribution of Choanocotyle hobbsi from Western Australia to the Murray Darling Basin in New South Wales, however, the definitive host remains unknown in New South Wales.

Some Biological Aspects of Cultured Ompok Pabda (Hamilton, 1822) Collected from A Local Fish Farm in Mymensingh, Bangladesh

An experiment was conducted to observe some biological aspects including growth, sex ratio, gonadal maturity, artificial insemination, fecundity, fertilization, hatching and larval development of O. pabda in a private hatchery. Total weight of the sampled fish varied from 1.60±0.43 to 111.12±6.83 g and length varied from 3.57±0.65 to 21.22±1.84 cm with the SGR 2.85±0.18 and ADG 0.73±0.05. The length and weight of the fish had a strong correlation (r²=0.966). Female dominance over male has been observed in the species. The male to female ratio was 1:1.48. Females were 16.8 cm in length at first maturity, while males were 16.6 cm in length. The GSI of female were ranged from 2.93 to 4.77 with the mean of 3.77±0.60 during the study period. The fecundity of O. pabda was ranged from 5675 to 19626 with the mean of 12503±4192 for the corresponding length 21.23±1.71, body weight 111.12±7.6 and gonad weight 4.19±0.87. Fertilization rate, hatching rate and larval development observed during the experiment. Scattered diagram for length-weight, fecundity-length, fecunditybody weight and fecundity-gonad weight relationship shows a perfect correlation both arithmetically and logarithmically.

Empowering Indigenous Farmers with Fish Farming on South Sumatra Peatlands

Forest and land fire is mentioned as a main problem of peatlands occurring every year and has provided huge losses for all parties. The research aimed how to empower indigenous farmers with fish farming on South Sumatra peatlands. This research was conducted on peatlands in Ogan Komering Ilir (OKI) District. The sampling method was using cluster technique, questionnaire and through Focus Discussion Group (FDG). All collected data were analyzed with the SPSS version 21 program and the comparisons or analyzes the relationship between the variables were also analyzed. The research results concluded that the prospect of fish farming on peatlands is very prospecful. Empowering indigenous farmers can be done through local fish farming (e.g. fishes of gabus; tebakang; sepat siam; betok; gurami and toman), and introduced fish farming (i.e. fishes of patin siam; catfish, and nila). Fish farming technology for empowering farmers can be focused on drainage and irrigation systems to maintain groundwater levels; and applying soil ameliorant (e.g. dolomite for fish ponds, lime, manure, urea and NPK fertilizer).

Histamine Level in Freshwater and Marine Fish Sold in Bulgarian Markets

Background: Histamine is an essential biogenic amine produced as a result of microbial decomposition of histidine during seafood processing and storage. The objective of this study was to evaluate histamine concentration in freshwater and marine fish marketed in Stara Zagora region, Bulgaria. Methods: Forty fish samples were purchased from local fish farms and retail stores in Stara Zagora, Bulgaria. Enzyme-Linked Immunosorbent Assay was used to determine histamine levels. The data were processed using GraphPad Software InStat 3. Results: Histamine was detected in 26 out of 40 (65%) samples, and none of them exceeded the regulatory limit of 200 mg/kg. The average histamine content in marine fish (6.965±3.187 mg/kg) was insignificantly (p>0.05) higher than that in freshwater fish (4.503±1.133 mg/kg). Conclusion: The results reveal low levels of histamine in freshwater and marine fish indicating their good quality. However, its presence in seafoods remains a major food safety problem that requires permanent regulation of histamine concentration in fish.

Genome based quantification of VHSV in multiple organs of infected olive flounder (Paralichthys olivaceus) using real-time PCR.

Viral hemorrhagic septicemia (VHS) is a serious viral disease that infects the olive flounder in South Korea. The Korean aquaculture industry experienced an economic loss caused by the high infectivity and mortality. This study aimed to evaluate the infection density of VHSV in various organs of the olive flounder including spleen, liver, kidney, stomach, esophagus, intestine, gill, muscle, heart, and brain. Olive flounders were collected from a local fish farm and injected subcutaneously with 106PFU/fish. Each 15 fish were sampled at 0, 3, and 7days post challenge (dpc), respectively, to perform quantitative analysis of VHSV using SYBR-green based real-time PCR in various tissues including spleen, liver, head-kidney, body-kidney, muscle, esophagus, stomach, intestine, gill, and brain. Organs infected with VHSV were obtained after 3 and 7days. Each organs were examined for viral infection using real-time PCR. The data obtained from this experiment revealed copy numbers higher than 10 copies per 100ng cDNA in the spleen (15.26 ± 3.11copies/100ng of cDNA), muscle (11.24 ± 2.25copies), and gill (14.23 ± 6.26copies), but lower in liver, head-kidney, body-kidney, esophagus, brain and stomach. The present study, together with previous data, demonstrated that the gill, spleen, and muscle are the major target organs of VHSV in olive flounder. Therefore, central monitoring of spleen, gill and muscle should be considered and might be necessary if anti-VHSV treatment is to be successful in infected olive flounder.

Generation of a white-albino phenotype from cobalt blue and yellow-albino rainbow trout (Oncorhynchus mykiss): Inheritance pattern and chromatophores analysis.

Albinism is the most common color variation described in fish and is characterized by a white or yellow phenotype according to the species. In rainbow trout Oncorhynchus mykiss, aside from yellow-albino phenotypes, cobalt blue variants with autosomal, recessive inheritance have also been reported. In this study, we investigated the inheritance pattern and chromatophores distribution/abundance of cobalt blue trouts obtained from a local fish farm. Based on crosses with wild-type and dominant yellow-albino lines, we could infer that cobalt blue are dominant over wild-type and co-dominant in relation to yellow-albino phenotype, resulting in a fourth phenotype: the white-albino. Analysis of chromatophores revealed that cobalt blue trouts present melanophores, as the wild-type, and a reduced number of xanthophores. As regards to the white-albino phenotype, they were not only devoid of melanophores but also presented a reduced number of xanthophores. Cobalt blue and white-albino trouts also presented reduced body weight and a smaller pituitary gland compared to wild-type and yellow-albino phenotypes. The transcription levels of tshb and trh were up regulated in cobalt blue compared to wild type, suggesting the involvement of thyroid hormone in the expression of blue color. These phenotypes represent useful models for research on body pigmentation in salmonids and on the mechanisms behind endocrine control of color patterning.