耳石锶标记在识别鳙(Aristichthys nobilis)放流个体的可行性

Feasibility analysis of releasing individuals of Aristichthys nobilis identification based on otolith Sr markers

为探讨耳石微化学分析的相关方法和技术在鳙(Aristichthys nobilis)放流群体识别中的应用,以鳙的1龄幼鱼为研究对象,设置1、2、4、8、16 mg/L 5个浓度梯度的Sr Cl2溶液标记,利用元素电子显微探针技术(EPMA)检测获得了良好的标记图谱.面分布分析结果显示,暂养28 d后外源Sr在耳石的边缘形成明显的标记环,与对照组的蓝色边缘相比,高锶环带从黄绿色过渡到橘红色,随着标记浓度增大有加深的趋势.定量线分析表明对照组的Sr/Ca比值处于稳定的2.14±0.39,而不同浓度Sr的实验组Sr/Ca比值均出现一个较为明显的峰值范围(5.04~32.32),且外源Sr浓度与耳石边缘的Sr/Ca比值之间存在明显的线性关系,标记过程中对照组和标记浓度间的死亡率并没有显著差异.结果表明锶标记原理和方法在鳙的大规模放流群体标记是可靠和安全的,验证了耳石锶标记在识别鳙放流个体上的可行性.建议选择鳙放流前仔稚鱼和幼鱼,以4 mg/L设为外源Sr的最适标记浓度,标记持续时间为28 d以上为宜.

To explore the method of microchemistiy marking on the otolith of Aristichthys nobilis, the 1- year-old juveniles were reared at five different concentrations（ 1, 2, 4, 8, 16 mg/L） for 28 days, and the exogenous Sr sedimentation in otoliths were de-tected with electron probe microanalyzer （EPMA）. The mapping analysis showed that obvious strontium signatures in the edge of o-toliths of juveniles were produced at different concentrations of Sr. The yellow-green strontium bandappeared in low level, the deep red zone shown as the concentration gradually increased. Line analysis indicated that the Sr/Ca ratio of control group was stable at 2.14±0.39, but which in the experimental groups of the different concentrations all appeared quite dramatically peak strontium val- ue（ 5.04-32.32）. Significant linear relationship was found between exogenous Sr and the Sr/Ca ratio in the edge of otoliths. There was also no significant difference in death rate between control and experimental groups. All of these suggested that the method of Sr marking confirmed the feasibility in recognizing the releasing individuals of A. nobilis. We suggest that stock discrimination of A. no-bilis were marked in larval and juvenile and the concentration of exogenous Sr should be 4 mg/L, lasting for more than 28 days.