In Bangladesh, aquaculture is critically important in terms of providing food and nutrition, sustainable livelihoods, income, and export earnings. Nevertheless, aquaculture in Bangladesh has faced recent concerns due to climate change. Aquaculture is vulnerable to a combination of climatic factors, such as global warming, rainfall variation, flood, drought, temperature fluctuation, and salinity change. Considering the vulnerability of fish production to the impacts of climate change, tilapia farming is one of the possible strategies for adaptation to climate change. The positive culture attributes of tilapia are their tolerance to low water levels and poor water quality with rainfall variation, temperature fluctuation, and salinity change. In fact, tilapia farming is possible in a wide range of water environments, including freshwater, brackish water, and saltwater conditions. We suggest that appropriate tilapia culture strategies with institutional support and collaboration with key stakeholders are needed for adaptation to environmental change.

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This study aimed to isolate and identify probiotic bacteria from the gut of Barbonymus gonionotus and evaluate their effects on growth, hematological parameters, and breeding performances of the host. Five probiotic bacteria viz. Enterococcus xiangfangensis (GFB-1), Pseudomonas stutzeri (GFB-2), Bacillus subtilis (GFB-3), Citrobacter freundii (GFB-4), and P. aeruginosa (GFB-5) were isolated and identified using 16S rRNA gene sequencing. Application of a consortium of probiotic strains (1–3 × 1.35 × 109 CFU kg−1) or individual strain such as GFB-1 (1.62 × 109 CFU kg−1), GFB-2 (1.43 × 109 CFU kg−1), GFB-3 (1.06 × 109 CFU kg−1), GFB-4 (1.5 × 109 CFU kg−1) or GFB-5 (1.43 × 109 CFU kg−1feed) through feed significantly improved growth, histological and hematological parameters and reproductive performances of B. gonionotus compared to untreated control. Moreover, the application of these probiotics significantly increased gut lactic acid bacteria and activities of digestive enzymes but did not show any antibiotic resistance nor any cytotoxicity in vitro. The highest beneficial effects on treated fishes were recorded by the application of GFB-1, GFB-2, GFB-3, and a consortium of these bacteria (T2). This is the first report of the improvement of growth and health of B. gonionotus fishes by its gut bacteria.

Glossogobius giuris were collected during March to September 2013 from the Payra river to estimate the length-weight relationship with relative condition factor (Kn), fecundity, gonadosomatic index (GSI) and relation between fecundity and other parameters. The length-weight relationship was found to be Log W= 2.667 Log TL – 1.805 in male and Log W = 2.931 Log TL – 2.040 in female. The mean Kn were found to be 1.02±0.155 for male and 0.97±0.276 for female which indicates satisfactory condition of the fish population. The mean relative fecundity was ranged from 88495 to 264104 with a mean value of 171581±17855, having a average total length of 21.21±0.44 cm, body weight 70.22±4.62 g and gonad weight 2.74±0.31 g. The relationships among the fecundity, the total length, body weight, gonad weight were found to be linear and positively correlated. The mean GSI value was 3.42±0.33 and the highest GSI value was recorded 9.34±0.71 in the month of September. This study will help to introduce this species in sustainable aquaculture through proper management and for the development of induced breeding technique.