As a result of climate change, aquaculturists are seeking adaptive culture techniques for sustainable aquaculture. In this case, cage culture is a suitable technique that can mitigate the challenge of climate change, but due to the lack of knowledge of proper stocking density, often productions are not satisfactory. Therefore, the experiment was conducted to evaluate the influence of stocking density on growth and production of an endangered minor carp bata (Labeo bata) in cages for a period of 120 days in Padma River, Rajshahi, Bangladesh. On an average initial weight of bata fingerling of 5 g was stoked in cages under three treatments each with containing three replications using three different stocking densities (106, 71 and 35 fingerling/m3 for T1, T2 and T3, respectively). Supplementary feed (3% per body weight) was given to the cultured species twice in a day. The mean values of water temperature, transparency, pH and dissolved oxygen were in suitable range throughout the experimental period. Significantly (p<0.05) highest mean gross weight (85.82±0.70 g), specific growth rate (2.37± 0.02%), survival rate (83± 3.00%) and food conversion ratio (2.27± 0.03) was found in T3 rather than T2 and T1. The net production in terms of biomass (18.23±2.43 kg/cage) was significantly (p<0.05) higher in T2.The study suggests that, treatment T2 (71 fingerling /m3) as the optimum stocking density to produce maximum production by cage culture of Labeo bata.

The striped dwarf catfish Mystus cavasius being a least concern small indigenous fish it is necessary to protect the species from extinction in the near future. An experiment on production and economic feasibility of Mystus cavasius in cage was conducted for a period of six months from March to August 2020 in beel hilla at Naogaon district of Bangladesh. The study was carried out in nine cages (rectangular 8x5x2 feet size) under three treatments namely T1, T2 and T3 performed with the stocking densities of 46 fry m-2, 92 fry m-2 and 137 fry m-2 and designed each with three replications. The fish was fed with commercial pellet feed (containing 30% crude protein) twice daily at the rate of 5-7% of fish body weight. The total production was found to be significantly (p<0.05) highest in T3 among the three treatments. The net profit was better in T3 than T1 and T2 in terms of better production and money. So, stocking density of Mystus cavasius at the rate of 137 fry m-2 in cage could be an economically feasible aquaculture technique for fish farmers.

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The present study evaluated the potentiality of cage culture of stinging catfish (Heteropneustes fossilis) under different feeding regimes. Fish experiments were consists of three treatments (T1, T2 and T3), each with three replicates, and lasted for 90 days. The stocking density was 300 fry (~1.5 g) per cage. Fish were given commercial floating feed (28% crude protein) twice daily (in the morning and evening) at 5% (T1), 7% (T2) and 9% (T3) of body weight. Water quality parameters were monitored fortnightly. Mean values of water quality showed no significant difference among the treatments. Survival of stinging catfish was comparatively higher with T2 (83.1%) compared to T1 (81.6%) and T3 (79.3%). The specific growth rate was significantly higher in fish reared underT2 treatment than T1 and T3, corresponding to 1.91, 1.85 and 1.87% bwd-1, respectively. The net yield was also highest with T2 (1.74 kg) than those with T1 (1.57 kg) and T3 (1.60 kg). These data together with cost-benefit analysis among three treatments suggests that 7% feeding rate positively influence growth and production offish. Therefore, a daily feeding at 7% of body weight can be suitable for culturing stinging catfish in cages. J Bio-Sci. 30(1): 01-09, 2022 (June)

Naznin Nahar (2020). Co-designing Integrated Pest and Disease Management strategies in eggplant production in Bangladesh. PhD thesis, Wageningen University, Wageningen, The Netherlands, with summary in English, 164 pp. Integrated Pest Management (IPM) was developed in response to the crisis caused by unrestricted use of pesticides. The IPM concept matured over time and today, it stands on a solid conceptual basis and millions of farmers across the globe, especially in developing countries, have been trained in it through the Farmers' Field School approach. Nevertheless, adoption rate remains frustratingly low. This thesis tries to understand why IPM is so difficult to implement for smallholder farmers in developing countries and what is needed to make IPM work for them. Eggplant production in Bangladesh was taken as a case and it involved various Table of contents Chapter 1 General Introduction Chapter 2 Reducing damping-off problems in eggplant (Solanum melongena L.): a participatory testing of nursery management in Bangladesh Chapter 3 Disease management in eggplant (Solanum melongena L.) nurseries also reduces wilt and fruit rot in subsequent plantings: A participatory testing in Bangladesh Chapter 4 Technical efficacy and practicability of mass trapping for insect control in Bangladesh Chapter 5 Smallholders and pheromone traps: when does an opportunity become a risk?