| Summary: | 碩士 === 國立臺灣海洋大學 === 環境生物與漁業科學學系 === 94 === Abstract
Grey mullet (Mugil cephalus) exposed to different salinity (0, 17 and 34 psu) and lead concentrations. The fishes exposed at 17 psu are the most tolerant to lead. The 96-h LC50s were 1.65, 6.25 and 4.39 Pb2+ mg/l following exposed to 0, 17 and 34 psu. Examined the LT10, LT50 and LT100 lethal time is also the same trend with concentrations by 17 psu > 34 psu > 0 psu.
Oxygen consumption (O2 mg/g/h) and ammonia excretion (N mg/g/h) of M. cephalus were measured for individual fish exposed to different salinity (0, 17 and 34 psu) and 20 ppm lead concentration. The oxygen consumption increased directly with increased ambient salinity. The oxygen consumption was 0.73, 0.80 and 0.89 mg/g/h in control, while the fishes exposed to 0, 17 and 34 psu, respectively. The fishes exposed to 20 ppm lead and different salinity (0, 17 and 34 psu) after 20 days, the oxygen consumption decreased to 0.58, 0.64 and 0.67 mg/g/h, respectively.
Ammonia excretion decreased directly with increased ambient salinity in control. After 20 days exposure, nitrogenous excretion rate all is 0 μg/g/hr
Mugil cephalus exposed to 0, 1, 5, 10 and 20 ppm Pb2+ in 0, 17 and 34 psu were examined for Pb2+ in gill, the liver, gut, muscle and eyes after 1, 5, 10 and 20 days, respectively. Concentration of Pb2+ in the tissues increased directly with ambient Pb2+ concentration and exposure time. Following 10 days exposure to 20 ppm Pb2+ and 0 psu, Pb2+ concentrations were measured in gill (513.83 ug/g), liver (14.99 ug/g), gut (21.14 ug/g), muscle (6.36 ug/g) and eyes(6.82 ug/g), respectively. Following 10 days exposure to 20 ppm Pb2+ and 17 psu, Pb2+ concentrations were measured in gill (333.03 ug/g), liver (33.57 ug/g), gut (33.45 ug/g), muscle (7.33 ug/g) and eyes(6.68 ug/g), respectively. Following 10 days exposure to 20 ppm Pb2+ and 34 psu, Pb2+ concentrations were measured in gill (239.90 ug/g), liver (17.13 ug/g), gut (80.03 ug/g), muscle (13.51 ug/g) and eyes(11.77 ug/g), respectively.
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