Factors affecting the adoption of carp polyculture in Bangladesh

A study was conducted to determine the factors affecting adoption of pond polyculture in six villages of three districts namely Mymensingh, Bogra and Narshingdi in Bangladesh. In Mymensingh, 75% pond owners adopted carp polyculture technology whereas in Bogra and Narshingdi only 16% and 25% pond owners, respectively adopted this technology for fish production. The production of fish per unit area was found to be 5 to 10 times higher in Mymensingh compared to that of Bogra and Narshingdi. Fish farmers identified three main problems affecting the adoption of pond polyculture viz. lack of input used in aquaculture, low fish yield and lack of credit facilities for pond polyculture. The technological awareness of the farmers directly contributed towards use of inputs in culture ponds. The positive impact of technological dissemination found on input use, fish yield and uplifted socioeconomic condition.

HACCP based management system for improving quality of freshwater giant prawn, Macrobrachium rosenbergii

The study was conducted on the present status of HACCP based quality management system of golda, Macrobrachium rosenbergii farms in Fulpur region of Mymensingh. Information was collected on general condition of farms, culture systems and post-harvest quality management. In almost all farms, there is no or inadequate infrastructure facilities such as, road access, electric supply, telecommunications, ice, feed storage facility, vehicle for golda transportation, washing and toilet facilities. The problems associated with sanitation and hygiene was: widespread use of cow dung, poultry manure and construction of open toilet within the vicinity of prawn culture pond. Different grades of commercially available and locally prepared feeds were used for golda culture in the pond. Golda post-larvae (PL) of 40-50 days old were stocked with carp species. The price of golda PL ranged from Tk. 1.00 to Tk. 1.25/piece. The pond size varied from 50 decimal (0.2 ha) to 2.5 acre (1.0 ha) with an average depth of 2-2.5 m. The culture period of golda varied from April-May to November-December and survival rate ranged between 75 and 80%. Production of golda varied from 250-500 kg/acre (625-1,250 kg/ha). Harvested golda were transported to city market within 4 h. Two size grading were generally followed during pricing, e.g. Tk. 500 to 550/kg for >100 g size and Tk. 300/kg for <100 g size. The cost-benefit ratio was found to remain around 1:1.25 depending on availability of PL. Water quality parameters such as, water temperature, pH, dissolved oxygen, total alkalinity and chlorophyll a in five golda farms in Fulpur region were monitored. Water temperature ranged from 29°C to 33°C, dissolved oxygen from 2.28 to 4.13 mg/l, pH between 6.65 and 7.94, alkalinity from 44 to 70 mg/l and chlorophyll a concentration from 61.88 to 102.34 µg/l in the five investigated ponds. The Aerobic Plate Count (APC) of the water sample was within the range of 2.0x10^6 - 2.96x10^7 CFU/ml and of soil samples within the range of 6.9x10^6 - 7.73x10^6 CFU/g. Streptococcus sp., Bacillus sp., Escherichia coli, Staphylococcus sp., Pseudomonas sp. and Salmonella sp. were isolated from pond water and sediment. Different feed samples used for golda was analyzed for proximate composition. Moisture content ranged around 14.14-21.22%, crude protein 20.55-44.1%, lipid 4.67-12.54% and ash 9.7-27.69%. The TVB-N values and peroxide values of feeds used as starter, grower and fish meal were found within the acceptable ranges and samples were free from pathogenic organisms. A training was organized for the golda farmers on HACCP, water quality and post-harvest quality management of prawn.

Improved handling and preservation of freshwater giant prawn, Macrobrachium rosenbergii for producing safe and wholesome products

Studies were undertaken to evaluate the quality changes in freshwater giant prawn, Macrobrachium rosenbergii during various storage conditions of handling and preservation and producing safe and quality products. The samples kept in ice immediately after catch with head-on and head-less condition were found to be acceptable for 6 days and 7 days, respectively. Delaying of icing considerably shortened the shelf-life. The pH value increased from 6.36 to 8.0 after 10 days in ice. The initial average TVB-N value of sample increased from below 10 mg/100 g to 25 mg/100 g with the lapse of storage period. The Ca++ ATPase activity in presence of 0.1M KCl slightly decreased at the end of 10 days of ice storage. Immediately after harvest, initial aerobic plate count (APC) was 2.88x10^6 CFU/g which gradually increased to 1.12x10^8 CFU/g after 6 days in ice storage and showed early signs of spoilage. Initial bacterial genera in the prawn iced at 0 hours were comprised of Coryneform (22.21 %), Bacillus (7.40%), Micrococcus (11.11 %), Achromobacter (48.14%), Flavobacterium/Cytophaga (7.40%), Pseudomonas (3.70%) and Aeromonas (3.70%). During ice storage Coryneforms and Bacillus were always dominating along with less prominent ones - Micrococcus, Achromobacter and Flavobacterium. Studies were conducted on the stability of myofibrillar protein of M. rosenbergii under different storage and pH conditions. The influence of a wide range of pH on the remaining Ca++ ATPase activity of M. rosenbergii muscle myofibrils after storage at -20°C for 2 days, at 0°C for 2 days and at 35°C for 30 minutes demonstrated that ATPase activities were lower in acidic and alkaline pH regions and the activity remained relatively high. Mg++ ATPase activities both in presence and absence of Ca++ remained high at neutral pH compared to those of acidic and alkaline region. The solubility of myofibrillar protein decreased gradually both in acidic and alkaline pH regions. The study also examined the bacteriological quality of freshly harvested M. rosenbergii, pond sediment and pond water from four commercial freshwater prawn farms at Fulpur and Tarakanda upazilas in the district of Mymensingh. The study included aerobic plate count (APC), total coliform count, detection, isolation and identification of suspected public health hazard bacteria and their seasonal variation, salt tolerance test, antibiotic sensitivity test of the isolates and washing effect of chlorinated water on the bacterial load in the prawn samples. APC in sediment soil and water of the farm and gill and hepatopancreas of freshly harvested prawns varied considerably among the farms and between summer and winter season. The range of coliform count in water, gill and hepatopancreas ranged between 6 - 2.8x10^2 CFU/ml, 1.2x10^2 - 3.32x10^2 CFU/g and 1.43x10^2 - 3.89 x10^3 CFU/g, respectively. No coliform was detected in pond sediment sample. Suspected health hazard bacteria isolated and identified from pond sediment, water, gill and hepatopancreas included Streptococcus, Bacillus, Escherichia coli, Klebsialla, Salmonella, Staphylococcus, Pseudomonas and Aeromonas. Bacillus, Salmonella and Staphyloccus [sic], and were found to be highly salt tolerant and capable of growing at 10% NaCl. The antibiotic discs with different concentration of antibiotics were used for the sensitivity test. The organisms were found to be most sensitive against Tetracyclin and Gentamycin.

Seed production and culture techniques of climbing perch, Anabas testudineus

Six treatments each with 12 replications designed to optimize the dose of inducing agent PG to achieve fertilization and hatching success of climbing perch, Anabas testudineus were tested. The females were given single injection of 7-12 mg PG/kg body weight and the males were given 4 mg PG/kg body weight. Fertilization and hatching rate varied from 67±4.55% to 66±3.0% and 59±4.88% to 57±6.21% for the doses of 10, 11 and 12 mg PG/kg of body weight, respectively. The hormone dose had significant (P<0.05) effect on fertilization and hatching. Six mini shallow cisterns (570 cm x 105 cm) were used to investigate the efficacy of zooplankton and Artemia nauplii as feed for spawn rearing. Three-day old spawns were stocked in six mini shallow cisterns at a stocking density of 100 individuals/L of water. Two treatments each with three replications were used to develop culture technique of the climbing perch. In case of treatment-1, the spawns were fed with Artemia nauplii three times daily, while in treatment-2, zooplankton were used as feed in the same manner as in treatment-1. After 14 days of rearing, mean final weight of the fry of treatments-1 and 2 were 95.55±6.71 and 57.69±5.40 mg, respectively. In treatment-1, spawn fed with Artemia nauplii showed significantly (P<0.05) higher mean weight than the spawn fed with zooplankton (treatment 2).

Comparative feature on design, construction and installation of three different model of low cost solar tunnel dryers

The study was conducted in collaboration with the ECFC project of the FAO (BGD/97/017) in Cox's Bazar to develop a low cost solar tunnel dryer for the production of high quality marine dried fish. The study areas were Kutubdiapara, Maheshkhali and Shahparirdip under Cox's Bazar district. Three different models of low cost solar dryer were constructed with locally available materials such as bamboo, wood, bamboo mat, hemp, canvas, wire, nails, rope, tin, polythene and net. Size of the dryers were: 20x4x3 ft ; 30x3x3 ft and 65x3x3 ft with the costs of Tk. 3060, 3530, 9600 for dryer 1, 2 and 3, respectively having different models. The drying capacities were 50, 150, 500 kg for dryer 1, 2 and 3 respectively. The average temperature range inside the dryers were 29-43°C, 34-51°C and 37-57°C for dryer 1, 2 and 3 respectively as recorded at 8:30h to 16:30h. The relative humidity were in the ranges of 22-42%, 27-39% and 24-41 % in dryer 1, 2 and 3 respectively. The fish samples used were Bombay duck, Silver Jew fish and Ribbon fish. The total drying time was in the range of 30-42, 28-38 and 24-34 hours to reach the moisture content of 12.3-14.5, 11.8-14.3, and 11.6-14.1% in dryer 1, 2 and 3 respectively. Among these three fish samples the drying was faster in Silver Jew fish followed by Bombay duck and Ribbon fish in all the three dryer.

Quality assessment of traditional and solar tunnel dried SIS (Small Indigenous Fish Species) products

Studies were conducted to assessment the quality of traditional and solar tunnel dried SIS products. The moisture content of the solar products ranged from 14.38 to 18.48% with the lowest in batashi and the highest value in tengra. The moisture content of the traditional products was in the range of 23.26 to 26.42%. The range of protein contents on moisture free basis was from 67.57 to 71.90% in solar dried fishes with highest value obtained in dhela and lowest value in batashi. These values were more or less similar to those of traditional dried SIS products which were in the range of 68.02 to 73.54% on dry weight basis. Lipid contents of solar dried SIS varied from 14.10 to 16.26% and on moisture free basis the in the range of 11.73 to 21.98 with highest value found in tengra and lowest in puti. These values were more or less similar to those found for traditional dried products on dry weight basis and ranged from were 12.37 to 22.43%. Maximum reconstitution of solar dried products was obtained at 80°C in all samples and was in the range of 65.26 to 70.51% where the percentage of reconstitution increases with the increase of socking time and reach maximum at the end of up to 60 min. The TVB-N content of solar dried fish is low compared with traditional one ranging from 20.30 to 28.40mg/100g and peroxide value in the range of 12. 54 to 19.20meq./kg oil. The TVB-N of traditionally dried products were in the range of 32.50 to 45.45mg/100g and PO values of the traditionally dried products were in the range of 30.00 to 36.00meq./kg oil. The bacterial load of the solar dried products was in the range of 4.0x10 super(3)/g to 3.6x10 super(5)CFU/g and of the traditionally dried products ranged from 1.45x10 super(5) to 2.52x10 super(6) CFU/g.

Quality assessment of traditional, rotary and solar tunnel dried small indigenous fish species products

Studies on the quality assessments of three traditional, rotary and solar tunnel dried SIS products were conducted. Organoleptic quality of traditional dried SIS products available in the markets was poor compared to those produced in rotary and solar tunnel dryer. Reconstitution of samples were in the range of 54.26% to 75.24%, 69.37% to 83.73% and 55.08% to 80.24% when soaked at 80°C for traditional, rotary and solar tunnel dried products, respectively. The percentage of reconstitution increased with the increase of soaking time and the uptake of water was maximum after 60 min of soaking. The moisture contents of traditional, rotary and solar tunnel dried products were in the range of 26.02% to 27.33%, 16.23% to 22.84% and 13.71% to 19.30%, respectively. The protein contents were in the range of 60.78% to 72.59%, 62.17% to 76.27% and 61.11% to 76.00%, respectively; lipid contents were in the range of 12.26% to 22.60%, 14.00% to 24.71% and 13.92% to 22.39%, respectively and ash contents in the range of 15.11% to 16.59%, 8.32% to 13.51% and 8.71% to 16.45%, respectively on dry matter basis. The TVB-N content of rotary and solar tunnel dried products was low compared to traditional one ranging from 10.64 to 17.52 mg/100g and 14.34 to 15.68 mg/100g, respectively whereas the TVB-N content of traditional samples was in the range of 15.46 to 20.36 mg/100g. The bacterial load of traditional, rotary and solar tunnel dried products were in the range of 1.43x10 super(8) CFU/g to 2.89 x10 super(80 CFU/g, 1.91x10 super(8) CFU/g to 2.84x10 super(8) CFU/g and 1.95x10 super(8) CFU/g to 2.59x10 super(8) CFU/g, respectively. The results of the study indicated that dried fish products from rotary dryer and solar tunnel dryer were found to be of better quality in nutritional and food quality aspects than those of traditional dried products.

Spawning behaviour and induced breeding of an estuarine catfish, Mystus gulio (Ham.)

Spawning behaviour of hormone induced estuarine catfish, Mystus gulio was observed in captive condition. Spawning activities that include pairing, chasing and resting, nudging, and twisting, started about 5 hours post injection and ended with release of eggs within 1-2 hours of courtship. Three different dosages of "ovaprim" (1 ml/kg, 1.5 ml/kg, and 2 ml/kg in a single dose) were used in induced breeding of M gulio. The latency period was less (6-7 hours) with the dose of 1.5 and 2 ml/kg, while it was more (7-8 hours) with that of 1 ml/kg. However, all females spawned successfully with each of three different dosages, without any significant differences in the rate of fertilization and hatching. Eggs under all hormone dosages hatched between 18-20 hours after spawning. The hatching rate with 1, 1.5, and 2 ml/kg varied from 71.3-72.7%, corresponding to the fertilization rate of 80.7-84.7%.

Shelf-life of rotary and solar tunnel dried SIS products under different packaging and storage conditions

A study was conducted on the shelf-life of rotary and solar tunnel dried SIS products under different packaging and storage conditions. Organoleptically dried products were found in good condition after a storage period of 60 days in ambient and chilled conditions. The moisture content, TVB-N value and bacterial load slightly increased during 60 days of storage in ambient and chilled conditions. The changes in moisture content and bacterial load were faster in ambient temperature than in chilled storage condition whereas changes in TVB-N value was higher in chilled condition than in ambient temperature. The initial moisture content was in the range of 13.71% to 22.84%. After 60 days of storage in ambient and chilled condition the moisture content of dried products was in the range of 15.09% to 25.11% and 14.49% to 25.01%, respectively. The initial TVB-N value was in the range of 10.64 to 17.52 mg/100g and after 60 days of storage in ambient and chilled condition, TVB-N value was in the range of 29.00 to 34.82 mg/100g and 31.41 to 39.11 mg/100g, respectively. The initial bacterial load was in the range of 1.91x10 super(8) to 2.84x10 super(8) and after 60 days of storage in ambient and chilled condition, the bacterial load was in the range of 6.2x10 super(8) to 1.8x10 super(9) and 5.75x10 super(7) to 5.05x10 super(8) CFU/g, respectively. The results of the present study indicated that it is necessary to store high quality dried products in sealed packed in chilled condition to ensure good quality up to a certain period of time.

Organoleptic, biochemical and bacteriological aspects of the low cost tunnel dried fish products

Studies were conducted on the organoleptic, biochemical and bacteriological aspects of three dried fish products produced from two different model of low cost solar tunnel dryer. The overall quality of the products obtained from both dryers was excellent. Sixty minutes soaking showed the maximum water reconstitution of the products with values between 66.82 to 75.28% and 71.98 to 78.09% in dryer 1 & 2 respectively. The highest reconstitution was obtained from Silver Jew fish (75.28-78.09%) and lowest from Bombay duck (66.86-71.98%) from both dryers. The average moisture, protein, lipid and ash content of the dried products were 11.8-15.0%, 57.32-68.49%, 6.08-8.62% and 12.25-14.88% respectively in fish in dryer 1 and dryer 2. The TVB-N values were in the range of 24.3 to 30.9 in dryer 1 and 22.1 to 28.2 mg/100 g samples in dryer 2. The highest values were obtained from Bombay duck and lowest value in Silver Jew fish in both dryers. The peroxide values varied from 14.1 to 16.9% in dryer 1 and 13.3 to 16.4% in dryer 2. The highest peroxide value was obtained from Ribbon fish and lowest from Silver Jew fish. Total bacterial load varied in the range of 6.6x10⁴— 8.6x10⁴ CFU/g in dryer 1 and 2.54x10⁴ to 4.9x10⁴ CFU/g in dryer 2. The highest value was obtained from Ribbon fish and lowest from Silver Jew fish.

Smoking of shrimp and fish from coastal village of north-west Bangladesh

Traditional smoking of mixed shrimp species is a method of preservation in coastal region of Bangladesh. Besides traditional smoked shrimp, attempt had been made to produce smoked shrimp from brown shrimp, Metapenaeus monoceros and fish from mugil, Liza parsia and the quality of smoked product was found good very on the basis of physical properties, proximate composition and mineral contents of the products.

Distribution, prevalence and intensity of protozoan and monogenean parasites of carp fingerlings in selected nursery ponds

An experiment was carried out on the distribution, prevalence and intensity of infestation of protozoan and monogenean parasites of carp fingerlings in two selected areas of Bangladesh. Six hundred and forty fingerlings of seven species viz. Catla calla, Hypophthalmicthys molitrix, Labeo rohita, Ctenophalyngodon idella, Cyprinus carpio, Barbodes gonionotus and Cirrhinus cirrhosus from different nursery ponds of Shambhuganj, Mymensingh, and Santaher, Bogra were examined during this investigation. This study revealed that carp fingerlings carried a large number of protozoan and monogenean parasites. Different protozoan parasites viz Trichodina domerguei, Trichodina reticulata, Myxobolus koi, Chilodonella cyprini and monogenean parasites such as Dactylogyrus extensus, Dactylogyrus catlarius and Dactylogyroides tripathi were identified in the experimental fishes throughout the study period. It has been observed that distribution, prevalence and intensity of parasite in carp fingerlings are species and zone specific. In case of C. cirrhosus, the highest prevalence of protozoan parasite viz Trichodina domerguei were 93.75% and 75.92% in Santhahar and Shambhuganj area respectively. Irrespective of host, the most prevalent ectoparasite was Dactylogyrus extensus, followed by Myxobolus koi, Chilodonella cyprini and Dactylogyroides tripathi. Relatively higher mortality of carp fingerlings was found at younger stage. The highest prevalent parasitic species was identified as Trichodina domerguei followed by Trichodina reticulata and Dactylogyrus catlarius were found 93.75% in Cirrhinus cirrhosus, 68.75% in Cyprinus carpio and 39.44% in Hypophthalmicthys molitrix respectively.

Year-round and rotational freshwater prawn, Macrobrachium rosenbergii and paddy farming: soil quality, production and economics

A study was carried out at five upazillas (Dumuria, Fakirhat, Pirojpur sadar, Gopalgonj sadar and Kalia) of five southern districts of Khulna, Bagerhat, Pirojpur, Gopalgonj and Narail to understand the comparative production performance and any effect on soil quality in case of year-round golda (Macrobrachium rosenbergii), alternate prawn-paddy and year-round paddy farming. A direct interview of 55 farmers was taken, using pretested questionnaire, and soil samples were taken from selected farms before and after each crop. Among the five upazillas, farmers in Gopalgonj sadar and Kalia are not practicing year-round golda. Rotational golda-paddy farming has been recorded to result in maximum profit, with the highest of Tk. 310,912/ha/year in 2003 at Dumuria. Only paddy farming is less profitable than other two cropping patterns, irrespective of study sites. The nutrient status of soil in rotational golda and paddy farming has been found improved, compared to that of only golda or paddy farming.

Production of quality dried small indigenous fish species products using low cost solar tunnel drier

A low cost solar drier was constructed using locally available materials. The size of the drier was 20x3.6x3 having drying capacity of 80 kg of SIS (w/w). Optimization of moisture content was observed for mola, dhela, chapila, chanda and puti at temperature ranges between 40-45°C and 50-55°C in solar tunnel drier. There was little or no change in moisture content at temperature below 40°C during the first 3 hours. Then the moisture content declined gradually with the increase of drying period. On the other hand, at temperature between 50-55°C, moisture content started to decline after 2 hours of drying. The moisture content of the sample reached at about 16% after 26 hours of sun drying at 40-45°C and 20 hours at 50-55°C. The optimum temperature for producing high quality dried products was 45-50°C in solar tunnel drier. The temperature and relative humidity outside and inside the dryers (with fish) at various locations were recorded from 8.00am to 4.00pm. The normal atmospheric ambient temperature was recorded in the range of 25-37°C from at 8:00am to 4:00pm. During the same period the atmospheric relative humidity recorded was in the range of 30-58%. On the other hand, the maximum temperature inside the dryers was recorded in the range of 28-65°C. The lowest temperature recorded was 28°C in the morning and at 13.00pm the highest temperature 65°C was recorded. The maximum relative humidity 58% found in the afternoon and minimum of 28% at noon. There was inverse relationship between temperature intensity of sunshine and humidity which decreased as sunshine increased. In total, it took around 26 hours of drying to reduce the moisture level to about 16%.

Growth performance evaluation of genetically improved silver barb (Barbonymus gonionotus Bleeker) in different agro-ecological zones in Bangladesh

On farm trials of silver barb with other carps were carried out in 40 ponds during May to October 2005 in four agro-ecological zones viz., Trishal, Muktagacha, Parbotipur and Paikgacha in Bangladesh. In Trishal and Muktagacha zones, ponds were stocked with silver barb, silver carp and common carp at the stocking density of 11,500 fish/ha, whereas in Parbotipur and Paikgacha zones, ponds were stocked with silver barb, rohu, catla and mrigal at the stocking density of 10,000/ha. Among the ponds, 50% (20 ponds) were stocked with BFRI improved stock of silver barb (Treatment-1) and rest of the 20 ponds stocked with local silver barb stock (Treatment-2). The harvest weight of BFRI improved silver barb were 149±16.01, 168±18.06, 198±14 and 230±9.25g in Trishal, Muktagacha, Paikgacha and Parbotipur, whereas the data obtained at 113±15.52, 136±20.66, 170±17.0 and 205±12.10g for local stock of silver barb, respectively. In all trials, the harvest weight of BFRI improved stock showed significantly higher growth performance (P<0.05) over the local stocks.