| Summary: | 碩士 === 國立中山大學 === 海洋資源學系 === 84 === This study investigated some aspects pf feeding ecology of grey
mullet, Chelon macrolepis, in Kaohsiung harbor and its nearby
co -astal waters, southern Taiwan. Monthly sampling were
conducted from July 1994 to August 1995. The sampling area
included the Kaohsiung River, its harbor area and the nearby
offshore area. Adult fishes were caught by gill net and the
juveniles were collected by pond net at one site by the harbor
from April to June 1995. The fishes were measured total length
and body weight and then dissected out stomach. Stomach content
weight index, pre- centage of empty stomach, sand content index
and organic content index were calculated. The composition of
feeding was examined with microscopy. Moreover, the
microstructures of the gill raker were examined througt the
scanning electromicroscopic technique. Among the 1415 fish
samples in three locations no significant di -fference of SCWI
was found between male and female fishes. How- ever, the SCWI
in the harbor area was significantly higher than that of off
shore in any month. The ES% values in two area were in contract
to the SCWI. The monthly variation of the SCWI re- vealed that
the highest and lowest feeding intensity were found in May and
December, respectively. The major food composition of C.
macrolepis was different between sites. The results also rec-
ealed a dietary shift from omnivorous to herbivorous between
the juvenile and adult. The food composition of the grey mullet
also varied seasonally which was correlated to the natural
environ- ment. the dietary shift between the juvenile and adult
was eluci -dated by the increase of the length and loop number
of aliment- ary cannel. The distance between the gill raker,
secondary pro- cesses, tertiary expansions did not show any
decrease correspon- dent to the increase of fish size. However,
the finest distance at the tertiary expansions of the third and
fift gill rakers were finest enough to filter the food
particles for any size of grey mullet.
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