Food and feeding habits of Gonialosa manmina were done by the analysis of 197 guts of the fish using both occurrence and point methods and also by the Index of preponderance. As per Index of preponderance, the preferred food items were graded as cladocerans (65.34%-1 st ), copepods (20.96%-2 nd ), miscellaneous (8.89%-3 rd ), rotifers (2.81% 4 th ) and bacillariophyceae (0.77% 5 th ). High feeding intensity was observed during pre and post spawning months. Significant (P<0.01) positive relationships were observed between the total length (TL) and total gut length (TGL) (TGL=2.09799TL 0.89677 , r=0.963, t=10.22), total length (TL) and stomach length (StL)(StL=0.18447TL 0.7599 , r=0.997, t= 39.92), and total length (TL) and intestine length (IL) (IL=0.99105TL1.0256 , r=0.9854, t=16.37). Total fish length was slightly shorter than the gut length (1:1.31) and more than 91% animal nature gut contents confirmed that the fish was mainly a surface feeder zooplanktivore in Kaptai lake.

Length frequency based population dynamics of the small indigenous cyprinid fish, Amblypharyngodon mola from the Kaptai lake (an artificial water reservoir), Bangladesh were studied using the computer based FiSAT program. Growth parameters La and K were found to be 104.65 mm and 0.95 year-1 respectively. The annual rate of natural mortality (M), fishing mortality (F) and total mortality (Z) were found to be 1.22, 2.04 and 3.26 respectively. Exploitation rate (E) was 0.63, while maximum yield per-recruit (Emax) was estimated as 0.678. The suitable selection pattern (L50) was found to be 51.09 mm. The yield per recruit and biomass per recruit determined as a function of Lc/La and M/K were estimated as 0.49 and 1.28 respectively. The Wetherall plot provided estimates of La and Z/K were 103.38 mm and 3.31 respectively. Growth performance index (?? = 4.017) was found to be suitable. Virtual population analysis (VPA) showed that the maximum number of A. mola was caught between the total length of 75 to 93 mm with values of F exceeding to 2.04 year-1. The estimated mean biomass was found to be 2.81 metric tons. The fish was recruited in the fishery during March to October with maximum in July. DOI: http://dx.doi.org/10.3329/cujbs.v4i1.13398 The Chittagong Univ. J. B. Sci.,Vol. 4(1&2):141-151, 2009

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Larvicidal effects of distilled water, 50% ethyl alcohol, acetone and methanol extracts on seed of four plants viz. Sinapis alba (Linn.), Carica papaya (Linn.), Momordica charantia (Linn.) and Capsicum annuum (Linn.) were studied upon the mosquito larvae of Anopheles annularis Vander Wulp and Culex quinquefasciatus Say under normal laboratory conditions with average temperature and relative humidity of 31.1oC and 57.6%, respectively. Percentage mortality, probit mortality, chi-square and ANOVA values for the larvae, extracts and concentrations were calculated for 24 hours exposure period. Mortality was dose dependent. The values of LC50 of the seeds of S. alba on An. annularis at the application doses for the distilled water, 50% ethyl alcohol, acetone and methanol extracts were 3431.791, 1038.363, 1254.810 and 2269.975 ppm, respectively; for C. papaya were 804.008, 403.294, 597.165 and 573.241 ppm, respectively; for M. charantia were 10593.241, 5017.710, 5650.191 and 6075.204 ppm, respectively; and for C. annuum were 1274.968, 4637.201, 1604.852 and 1905.692 ppm, respectively. The values of LC50 of S. alba seeds on Cx. quinquefasciatus at the application doses for the distilled water, 50% ethyl alcohol, acetone and methanol extracts were 1415.311, 432.996, 569.701 and 770.250 ppm, respectively; for C. papaya were 705.599, 385.688, 341.003 and 481.067 ppm, respectively; for M. charantia were 7764.154, 4496.464, 5353.759 and 5825.031 ppm, respectively; and for C. annuum were 2173.631, 1311.538, 78.748 and 182.869 ppm, respectively. Of the four plant seed extracts, C. papaya seed extracts were the most toxic for both the mosquito species. J. Biodivers. Conserv. Bioresour. Manag. 2019, 5(2): 41-52