Determining overwintering performance and economic viability of monosex tilapia fingerling production in hapa cum cage aquaculture system for Bangladesh's haor fishers

Ensuring a consistent supply of uniformly sized fingerlings for tilapia cage aquaculture in Bangladesh's poses a significant challenge. This study assessed overwintering growth performance and economic viability of monosex tilapia fingerling production in haor waters. Nine hapas, each inside a designated treatment cage, were stocked with T1 (200), T2 (250) and T3 (300) tilapia fry, averaging 1.25±0.25 g, per m³ for 90 days. The most successful treatment continued for two subsequent crops over two years for economic viability assessment. Average final body weight gain was the highest at the lowest stocking density (T1, 58.86±7.23 g), but the most desirable biomass gain (222 kg cage⁻¹) occurred at medium stocking density (T2). Beyond biomass gain, T2 exhibited superior profitability, with 26% and 30% profitability in the second and third crops respectively, over total costs. In conclusion, overwintering tilapia fingerling production in the hapa-cum-cage system at a stocking density of 250 m⁻³ proved more profitable and sustainable than other treatments, offering a viable income-generating option for resource-poor haor fishers

Study on freshness quality and post-harvest loss of Hilsa (Tenualosa Ilisha) during marketing in Mymensingh town, Bangladesh

An investigation was conducted to know the freshness quality and associated post-harvest loss of hilsa, if any, transported to Mymensingh from the major landing centers through Cox’s Bazar-Chittagong (route A) and Barguna-Chandpur (route B) routes for a period of July to October 2012. The average environmental temperature of the wholesale and retail markets was 30.7 °C and 30.6 °C where the body temperature of hilsa was 4.5 °C (route A) and 4.7 °C (route B), respectively. The Freshness quality of hilsa was assessed using sensory defects points (DPs) that eventually gave rise to numerical values ‘1’ being the freshest and ‘5’ being the worst quality. The DPs of hilsa were found 2.0, which reveal that the fishes were in excellent conditions, i.e., there was no significant post-harvest loss even during retail sale. DPs on arrival and at wholesale in July, September and October were significantly different after auction and during retail sale (p<0.05), and in August differed significantly only during retail sale (p<0.05). It was observed that hilsa transported to Mymensingh from Barguna-Chandpur were better in quality than those transported from Cox’s Bazar-Chittagong. The reason behind this finding was not studied and this needs to be elucidated through further research

Efficiency of organic pesticides, turmeric (Curcuma longa) and neem (Azadirachta indica) against dry fish beetle (Dermestes sp.) during storage condition

Efficacy of turmeric (Curcuma longa) and neem (Azadirachta indica) or repelling dry fish insects (Dermestes sp. adult and larva) was investigated on the basis of their repellency rate, storage quality, sensory attributes of turmeric and neem treated dry fish and their cooked products. Pesticides prepared from turmeric and neem, were used in the form of extract and powder. The extracts were tested at the concentrations of 2%, 3%, 5% for turmeric and 3%, 5%, 7% for neem. Turmeric and neem powder were used for treatment at the rate of 2.0%, 3%, 4.0% upon 100 g dry fish. Repellency rate of Dermestes sp., adults was highest, where larvae showed mere resistance against herbal pesticides. Pesticides prepared from turmeric were more repellent than neem pesticides. Control and treated dry fish had almost similar sensory attributes after the 2nd month. However, odor, texture, general appearance and insect occurrence of control dry fish decreased significantly after 4th month of storage but all those parameter of treated dry fish were nearly unchanged. However, sensory quality of dry fish treated with turmeric and neem were remain unchanged after the 4th month. The results suggested that 3% extract and powder of turmeric or neem at the rate of 5% extract and 3% powder can be used as suitable field doses for direct application in dry fish to prevent insect infestation during storage of dry fish products

Factors Affecting Fishers’ Attitude and Willingness to use Cage Aquaculture as an Alternative Livelihood for Reducing Fishing Pressure in Haor Areas, Bangladesh

Inland capture fisheries are providing cost of livings of about 1.2 million BDT in Bangladesh. However, overexploitation causing the declination of the abundance of native fish species which adversely affects the livelihoods of haor dwellers. The present study was conducted in two haor villages (Sutarpara and Changnoagaon) of Kishoreganj, Bangladesh to explore the factors (economic and non-economic) affecting fishers’ attitude and willingness about cage aquaculture considered as livelihood alternative for reducing fishing pressure. The methodologies applied to do this study were semi-structured face-to-face interview, key informants and questionnaire survey using Likert scale (LS), focus group discussions (FGD). The result revealed that willingness to switch from traditional way of fishing to cage aquaculture activities was significantly (P<0.05) higher in those fishers’ groups that had more inclination in fishing activities. Simultaneously, non-economic factors like powerful traders and fishers, traditional belief, taking risk, launching period of cage aquaculture venture and investment duration played vital role in decisions on whether to fish or not. The economic factors were fewer in number than non-economic factors. This comparative research is significantly important for future social aquaculture researchers as well as the country policy makers for giving emphasis to gather data based on the prevailing economic and non-economic factors to innovate alternative livelihood activity concurrently