Temperature and depth distribution of Japanese eel eggs estimated using otolith oxygen stable isotopes
Temperature and depth distribution of Japanese eel eggs estimated using otolith oxygen stable isotopes
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使用耳石氧稳定同位素估算日本鳗鱼卵的温度和深度分布
DOI：
10.1016/j.gca.2018.03.006
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发表时间：
2018
影响因子：
5
通讯作者：
Valley John W.
中科院分区：
文献类型：
--
作者：
Shirai Kotaro;Otake Tsuguo;Amano Yosuke;Kuroki Mari;Ushikubo Takayuki;Kita Noriko T.;Murayama Masafumi;Tsukamoto Katsumi;Valley John W.
通过对采自日本两条河流的日本鳗鲡（Anguilla japonicglass eel）耳石核心区氧同位素比值的测定，验证了日本鳗鲡产卵期可能经历的温度和深度。为探讨耳石δ18O值与水温的关系，对4种不同温度（15、20、25和30 °C）下养殖的玻璃鳗耳石进行了分析。耳石δ18O值与环境水温呈负相关。海水δ18O的耳石氧同位素比值与水温之间的线性回归得到了一个精确的关系：δ18Ootolith，PDB− δ 18O海水，SMOW= −0.153 ×T（°C）+ 1.418。两个地点的玻璃鳗耳石核心区的δ18Ocore，PDB值分别为−2.53 ± 0.12和−2.59 ± 0.07，利用该公式并假设海水δ 18Owhatesale，SMOW= 0.06‰，可分别换算为26.3 ± 0.8 °C和26.7 ± 0.4 °C。在日本鳗鱼产卵区的水柱中，对应于这些温度的水深为150米，这对应于垂直水文剖面中温跃层和叶绿素最大值的最上部。这些结果与现场研究一致，卵发育开始后的耳石形成和孵化发生在温跃层的最上部，这表明稳定同位素微量分析是一个强大的方法来推断未知的鱼类产卵生态。
Oxygen isotope ratios of the core region of otoliths were examined inAnguilla japonicaglass eels collected from two rivers in Japan to verify the possible temperature and depth layer experienced by these eels when they were at the egg stage in their spawning area. To determine the relationship between otolith δ18O values and water temperature, the otoliths of glass eels reared under four different temperatures (15, 20, 25 and 30 °C) were analyzed. The otolith δ18O values showed an inverse relationship to ambient water temperature. Linear regression of the fractionation between otolith oxygen isotopic ratio from the δ18O of seawater and water temperature produced a precisely determined relationship from 15 to 30 °C: δ18Ootolith,PDB− δ18Oseawater,SMOW= −0.153 ×T(°C) + 1.418. The δ18Ocore,PDBvalues of the otolith core region of the glass eels from the two locations were −2.53 ± 0.12 and −2.59 ± 0.07 respectively, and could be converted to water temperatures of 26.3 ± 0.8 °C and 26.7 ± 0.4 °C, respectively, using the equation and assuming a seawater δ18Oseawater,SMOW= 0.06‰. The water depth corresponding to these temperatures is ∼150 m in the water column in the spawning area of Japanese eels, which corresponds to the upper-most part of the thermocline and chlorophyll maximum in the vertical hydrographic profile. These results were consistent with the field studies that egg development after the beginning of otolith formation and hatching occurs around the upper-most part of thermocline, suggesting that stable isotope micro-analysis is a powerful method to extrapolate unknown spawning ecology of fishes.