Abstract:The research was carried out to assess the trace metal concentration in sediments of ship breaking area in Bangladesh. The study areas were separated into Ship Breaking Zone and Reference Site for comparative analysis. Metals like iron (Fe)

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: An investigation was conducted to study the abundance and diversity of Small Indigenous Species (SIS) of fish in the Chalan Beel. Sampling was carried out frequently over a year in selected landing centres, fish markets and catch points. A total of 82 SIS fish belonging to 10 orders, 22 families and 46 genera were recorded. The order Cypriniformes (42.68%) was the most dominant order comprising 35 species. The most dominant family of the order Cypiniformes was Cyprinidae (77.14%) comprising 27 species, and Puntius was the largest genus including 7 species. The most abundant SIS fishes observed during the study period were Tengra (Mystus vittatus, M. tengara), Punti (Puntius sophore and P. ticto), Taki (Channa punctatus), Guchi Baim (Mastacembelus pancalus), and the least abundant SIS fish were Aplocheilus panchax, Badis badis, Danio sp. and Chaca chaca. Availability of the species were ranked as Few (39%), followed by Common (23%), Very Common (15%), Rare (16%) and Very Rare (7%). At Mohisluti fish landing centre (under Tarash, Sirajganj) the highest number of species (79, 96.34%) of small fishes were found. Abundance of different SIS fishes were found to vary with the season.

The larvae of Tribolium castaneum (Herbst) of different ages were exposed to various concentrations viz., 0.0001, 0.001 and 0.01 ppm of triflumuron up to pupation. The adults were allowed to feed on untreated diet. The preoviposition period, fecundity, egg viability and incubation period of the eggs laid were studied. Triflumuron significantly lengthened the preoviposition and incubation periods (P < 0.001). Fecundity and egg viability were also reduced (P < 0.001) due to the treatment. Both the strains were affected by the treatment.

Eggs of the lesser mealworm, Alphitobius diaperinus (Panzer) were exposed to UV-rays of 254nm wavelength for different durations viz. 1, 2, 4 and 8 minutes. After seven days of hatching, larvae of each exposure were reared separately on triflumuron (1 x 10-3 mg/kg) treated food and observed the population of various developmental stages e.g., egg, larval, pupal and adult at storage periods of 3-, 6-and 9-months. UVrays and triflumuron treatments deleteriously reduced the populations of all the developmental stages of A. diaperinus. Egg and pupal populations of the beetle were adversely influenced by the storage periods also. Complete reduction of A. diaperinus populations was achieved from 6-9 months storage periods, when eggs were exposed to UV-rays for 8 minutes.