以耳石微化學解析台灣海峽烏魚的洄游環境史
Date Issued
2004-07-31
Date
2004-07-31
Author(s)
曾萬年
DOI
922611M002019
Abstract
To understand the life history, estuarine recruitment dynamics, and migratory
environmental history of the grey mullet Mugil cephalus in the coastal waters of
Taiwan, I examined the relationship between Sr/Ca ratios and ambient salinity, and
analysed otolith microstructures and Sr/Ca ratios in juveniles sampled in estuaries and
in adults from various habitats.
A validation experiment indicated that the relationship between Sr/Ca ratios in
otoliths of juvenile mullet and ambient salinity was non-linearly related. Ca and Sr
contents in the rearing water increased linearly with salinities from 0-35‰. Sr/Ca
ratios in the rearing water was non-linearly related to salinity; ratios increased
approximately 2 fold from 7.9±0.4×10-3 in 0‰ freshwater to 15.1±0.6×10-3 in 5‰
seawater and remained constant of 14.0±0.8×10-3 in salinities from 5-35‰. In contrast,
Ca content in the new increment of otoliths deposited during the 30 day rearing period
did not change with salinities ranging from 0 to 35‰, averaging 38.6±0.4%. Sr
content and Sr/Ca ratios in the otoliths increased approximately 2-fold from
0.1±0.01% (Sr) and 3.2±0.4×10-3 (Sr/Ca) in 0‰ freshwater to 0.2±0.03% (Sr) and 6.4±0.7×10-3 (Sr/Ca) in 5-35‰ seawater, which was consistent with the change in
Sr/Ca ratios of the rearing water. In addition, Sr/Ca ratios in otoliths of fish reared in
5-35‰ seawater were negatively correlated with the otolith growth rate. These results
indicate that Sr/Ca ratios in the otoliths were interactively affected by salinity and fish
growth rate, which can be used to reconstruct environmental history of the mullet by
differentiating fish migration between freshwater and seawater.
Subjects
Grey mullet
Mugil cephalus
Otolith
Strontium
Calcium ratio
Recruitment dynamic
Migratory environmental history
Publisher
臺北市：國立臺灣大學漁業科學研究所
Type
journal article
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