SOME ECOLOGICAL ASPECTS OF MACROGNATHUSAMI (BLOCK AND SCHNEIDER, 1801) km MACROGNATHUS ZEERINVS (BLYTH, 1859) IN THE ENVIRONS OF HTANTABIN, VANGON REGION

PhD (DISSERTATION)

/'A'

TIN TIN MAW

DEPARTMENT OF ZOOIDGY UNIVERSITY OF YANGON MYANMAR

••> .1 % • 'ft, 'A- DECEMBER, 2012 ABSTRACT

Population abundance of Macrognathiis aval and Macrognathus zebrinus in West Yangon University campus, Deik kone village, Rakhine Yoe Gyi village, Yaidwingone village and Aye Myo village was studied during April 2010 to March 2012. Population of both studied species in Htantabin environs was abundant during June to December. The population abundance of M aral and M zebrinus among five study sites was significant throughout study period. Significant positive correlation between population abundance of two Macrognathus species and rainfall was observed in study site III during both study period. Significant negative correlation between population abundance of M. aral and temperature was observed in the study site II although that ofM. zebrinus was observed in all study sites in two study years. Comparatively, monthly and mean abundance of M. zebrinus was higher than those of M. aral Length of digestive tract of male and female M. aral and M. zebrinus was 1.5 times shorter than that of the standard length. The food of sources such as , shrimp and crabs, scales in male and female of two study species was more than other food sources such as mud, detritus and miscellaneous. Females of both species were dominant in 2010-2011 and male of M aral were dominant in 2011-2012 although mean sex ratio of M. aral and M. zebrinus were not significantly different from theoretical distribution. According to the GSl value, both species of fish spawn once a year during rainy season. Length-weight relationship ofboth study species was significant. Total length of both study fish species was not significantly different but significant in body weight. In accordance with the value of exponent b, the growth of M aral was negative allometric and that of M. zebrinus was positive allometric.

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