Research
Population Dynamics Study of Ribbonfish, Lepturacanthus savala from the North-Eastern Tip of Bay of Bengal
Land-based survey data were collected from two major fish landing centers of south-east Bangladesh. A total of 1,770 Lepturacanthus savala individuals were collected for length- frequency and length-weight analysis. The asymptotic length (L∞), growth coefficient (k), theoretical age with length at zero (t 0 ) and growth performance index (Ø') were estimated to be 111 cm, 0.34 year -1 , -0.34 year and 3.622 respectively. Based on the growth parameters total mortality (Z), natural mortality (M) and fishing mortality (F) was found 1.09 year -1 , 0.611 year -1 , and 0.479 year -1 respectively. The exploitation rate (E) using the length converted catch curve was found as 0.43 year -1 which denotes that the studied population is not in over-exploited condition. Recruitment pattern revealed the peak in July. Length-weight relationship of L. savala was established as W = 0.0381 TL 2.1194 where R 2 = 0.8697.
Propensity of using Harmful Gas Controller and Oxygen Supplier on the Basis of Fish Farmers Age, Educational Status and Landownership of Six Upazilas in Noakhali District, Bangladesh
The intensity of aquaculture is increasing day by day in Bangladesh. To meet the increasing demand new technologies are being used to enhance production. Recently the use of fish medicines in aquaculture is also seen among the farmers of our country. In the present study, the propensity of using harmful gas controller and oxygen supplier on the basis of farmers’ age, educational status and land ownership were studied. The study was conducted in six upazilas of Noakhali district, Bangladesh. Data were collected through questionnaire survey of 77 fishermen by interviewing with them and discussing with the upazila fisheries officer, retailers of fish medicines and representatives of pharmaceutical companies and market survey. The propensity of using harmful gas controller was higher than any other medicines used by farmers of all upazilas surveyed. In the case 36% farmers showed their tendency to use, because most of the farmers had problems with harmful gases in their ponds. In case of oxygen supplier 22% farmers used oxygen in their ponds. Most of the farmers’ age ranged between 26-35 and 36-45 years who showed more tendencies to apply both medicines in their ponds. It was also found that the farmers whose education level was above higher secondary school certificate (HSC) showed more tendency to apply medicines. Farmers who were rich having 6 and above acres of land showed more tendencies than poor and moderately rich farmer to apply medicines in their ponds. The study clearly showed that, there was a relationship between farmers’ age, educational status and land ownership with the adoption of harmful gas controller and oxygen supplier.
