| Summary: | 碩士 === 國立中山大學 === 海洋資源學系 === 87 === The principal objectives of this research are to investigate temporal and spatial variability of the Hyperiidea in relation to environmental factors in the adjacent waters of Kaohsiung and Liu-chiu Yu island, southwestern Taiwan during the period from March 1997 to February 1998. In this study, I dealt with the species composition and numerical abundance of seasonal variation, diel vertical migration and vertical distribution of the Hyperiidea.
A total of 104 samples (56 of 1-m net and 48 of multiple opening/closing net) were examined. Eighty-seven species of the Hyperiidea belonging to 37 genera were identified and the mean numerical abundance of the hyperiids was 88.7±121.3 ind./100m3. The most dominant and frequent species was Lestrigonus bengalensis (average >50% of the total catch). The four most dominant and frequent species, namely, L. bengalensis、Hyperioides sibaginis、Eupronoe maculata and Amphithyrus sculpturus, comprised over 70% of the total catch of hyperiids. The hyperiid fauna exhibited seasonal variations in numerical abundance and species number, with higher abundance and species numbers in summer and fall than those in winter.
The species composition and numerical abundance of the Hyperiidea were different between the inshore and offshore stations, and varied seasonally. The inshore stations were likely affected by river effluent, particularly in the raining season. Though the numerical abundance of the total hyperiid fauna was not correlated with temperature and salinity (p>0.05), but the occurrence and distribution of individual species might be influenced by these environmental factors.
The numerical abundance of hyperiids in surface water was higher at night than during the day. The weighted mean depth of most hyperiid species were above 100m depth and the ranges of their migration were mostly within 100m. The diel vertical migration of the Hyperiidea in our study area can be roughly classified into three categories: nocturnal (Lestrigonus bengalensis、Hyperioides sibaginis、Primno brevidens, and Amphithyrus muratus), reverse (Eupronoe minuta、E. maculata, and Themistella fusca), and non-migratory (Phronimopsis spinifera and Phrosina semilunata).
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