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Nutritional composition of wild earthworm (Perionyx excavatus) and fishmeal used by local fish-feed industry in Bangladesh was determined to evaluate the nutritionally replacement potentiality of this earthworm species for fishmeal mostly used in feed for aquaculture and other animal production. Except for moisture content, the proximate chemical values in P. excavatus did not differ significantly (P≥0.05) from that in fishmeal. On an average, the earthworm had lower protein content (46.57 ± 0.97%) than fishmeal had (54.97 ± 7.49 %). On the other hand, the mean lipid content (8.03 ± 0.44 %) in this earthworm was found to be higher compared to fishmeal (7.97 ± 1.60 %). The average ash content in the earthworm and fishmeal were 24.26 ± 0.68 % and 24.13 ± 8.44 %, respectively. The results of the present study indicate that this earthworm species had almost similar nutritional values to the fishmeal, and thus would be a potential source of animal protein in supplementing fishmeal. In an implication, year-round production of this earthworm species through standard mass culture system, and its radical use could play a pivotal role in sustainable fisheries and aquaculture production.

This paper evaluates the production pattern and economics of freshwater prawn (Macrobrachium rosenbergii) farming in seasonally saline rice fields in Bangladesh. The reconnaissance survey was conducted on 30 rice-prawn ghers (RPG) in south-west region of Bangladesh. The farmers were found to use their rice fields for farming prawn and rice (aman) concurrently from April/May to January, and for only rice (boro) from January to April. In the RPG farming system, farmers use rain water during wet season, and underground water with salinity of 1-5 ‰ during dry season. The average production of prawn, aman, and boro was recorded as 439.79±90.46, 3155.48±397.33, 4778.54±389.37 kg/ha/yr, respectively. The economic analysis show potentially good return, and the net return and benefit-cost ratio were US$ 1078.35 and 1.25, respectively. The payback period was determined as 9.37 years. The study implies that the culture of prawn in seasonally saline paddy field is economically viable.