Fish parasitological investigation and research performed in Bangladesh has

A study was conducted on culture practices of shrimp at farmers' level in Bagerhat District. Investigation was based on a sample of 123 shrimp farmers from the seven Thanas (Fakirhat, Mollahat, Sadar, Rampal, Mongla, Chitalmari and Kachua) of the District, 73.17% farmers produced shrimp with white fishes. Farmers (54.47%) started to culture during 2000-2004 in this area. The culture period was typically four months for bagda and six to seven months for golda. Hatchery PL are stocked mainly in May to June for prawn and from late March for bagda. The average stocking density of shrimp PL golda and bagda was 24.16 and 12.16 thousand/ha in the farms. Varieties of feeds such as cooked rice, fishmeal, oilcake and snail muscle were used for shrimp culture. Mainly virus disease was responsible for the great loss of shrimp in this area. About 46.34% of the surveyed farms faced a huge damage due to WSBV. The average bagda and golda production was 350.37 kg and 428.08 kg/ha/year. Long term sustainability of shrimp farming facing problems due to lack of money, poor supply of good quality PL, lack of technical knowledge, higher production costs and poor institutional support. It might be however, necessary to establish shrimp hatcheries and provide training facilities, extension service, institutional and policy support to the farmers with the help of DoF and NGOs.

An investigation was conducted on infestation and reviewed biodiversity of metazoan parasites in Channa punctatus of Mymensingh region from July 2013 to June 2014. A total of 235 fish were examined and 9 species of four groups of parasites were recorded. They were (i) Euclinostomum multicaecum Tubangui and Masilungan, 1935 (ii) Euclinostomum heterostomum (Rudolphi, 1809) (iii) Genarchopsis goppo Ozaki, 1925 (iv) Allocreadium handiai  Pandey, 1937 (v) Senga ophiocephalina (Tseng, 1933) (vi) Porrocaecum sp. (vii) Ascaridia sp. (viii) Contracaecum sp. (ix) Pallisentis ophiocephali (Thapar, 1930).The maximum (86.67%) prevalence was found in  (86.67%) October and minimum (35.00%) in December whereas the maximum mean intensity (10) was observed in June and the minimum (1.42) was recorded from December. The prevalence was observed higher (68.85%) in smaller size of fish and in case of larger fish the prevalence was lower and the value was (53.62%). On the other hand, the mean intensity (5.45) was higher in smaller fish and lower (3.39) in medium sized fish. Both prevalence and mean intensity was found maximum in female fish than male fish. Among the four groups of parasites, infestation of Digenetic trematode is much higher than Nematoda, Cestoda and Acanthocephala. During the study, a list of parasites reported from Channa punctatus of Indian sub-continent was prepared. It was found that 38 species of Digenea, 4 species of Cestoda, 26 species of Nematoda and 5 species Acanthocephala were recorded. The Biodiversity of parasites seemed to be declined day by day. The responsible factors for this declination may be environmental degradation, entry of exotic fish and modernization of aquaculture etc. J Bangladesh Agril Univ 17(3): 409–416, 2019

An investigation was made on prevalence of the parasite Genarchopsis dasus in the fish Channa punctatus of Mymensingh, Bangladesh to determine the infestation and seasonal variation. The experiment was carried out from December 2009 to November 2010. A total of 379 parasites were collected from 235 host fish. The prevalence of G. dasus was higher in July and lower in September and October. The highest prevalence (83.3%) was in rainy season and the lowest (45.5%) in autumn. The highest intensity of G. dasus was in July and the lowest in December, and the highest and lowest intensity was in rainy and winter seasons, respectively. The prevalence was highest in intermediate length fish (67.0%), where the lowest (54.9%) was in small fish. Intensity was highest in intermediate length fish. The higher prevalence (90%) and intensity (4.3) was in female during rainy season. The lower prevalence (32%) and mean intensity (1.1) was in male during autumn. The highest ratio of mature: immature was in summer (30 : 37), the highest percentage of mature worms was in summer and the highest proportion of immature worms in autumn. The stomach contained most worms (72.8%) and the lowest proportion (6.6%) was in anterior portion of intestine. (Bangl. vet.

An economic anylysis was made to determine the cost of fish production in the floodplains at Daudkandi Upazilla in Comilla district during the period form January to April, 2007. Survey method was followed to collect data from 20 floodplain aquaculture projects. The projects record books and personal interviews of the NGOs and Fisheries officers were the main instruments of data collection. Statistical tools such as: range, mean, standard deviation and percentage were employed for analysis of data. The Cobb-Douglas production function model was used to estimate the values of co-efficients and related statistics of production function of fish culture in floodplains. Out of eleven explanatory variables, seven co-efficients had positive sign while only four co-efficients showed negative sign. The co-efficients bearing positive sign i.e., embankment construction, nursery and land lease, fertilizer and lime, fingerlings, feed, labor and staff wages and miscellaneous cost made positive impact on the farm income, while the co-efficients having negative sign i.e., area of floodplain, Office management, compensation and harvesting and marketing cost decreased the farm income. Summation of the production co-efficients i.e., return to scale (∑bi) was found 1.023 which implies that per one taka investment in floodplain fish culture will give rise to a profit of Tk. 1.02. The value of R 2 was found 0.892, which means that the variations in farm income could be explained to the extent of 89.2% by the included variables. The remaining 10.8% variations could not be accounted for by the multiple regression analysis. Average fish production in the selected floodplains was 2920.43 kg/ha of which production of cultured fish and indigenous fish was 2697.35 and 223.08 kg/ha respectively. The cost of fish production, total return and net income were estimated Tk. 1,153,08.55, 1,76,385.49 and 61,076.94 /ha. respectively. Benefit cost ratio was found 1.53.