鲤稚鱼耳石锶标记效果

Effectiveness of otolith strontium marking for juvenile Cyprinus carpio

对鲤稚鱼开展了不同浸泡浓度和不同标记时间梯度的SrCl2·6H2O暴露标记试验,以确认其耳石Sr标记的可行性及基本条件.首先,基于4个浓度(0、4、8、12 mg·L-1)水平的SrCl2·6H2O溶液,浸泡标记2 d来筛选基本浸泡标记浓度.然后,在SrCl2·6H2O为8 mg·L-1浓度下,基于5个浸泡时间(1、2、3、4、5 d)来筛选基本浸泡标记时间.电子探针分布分析结果显示:对照组(0 mg·L-1)耳石Sr/Ca比值低且稳定,标记组均出现了高Sr/Ca比值区.对照组耳石剖面为均一的低Sr蓝色图谱,而标记组耳石上均有高Sr红色标记环带,且标记成功率为100%.试验期间,标记组和对照组的死亡率、平均全长和平均体质量无显著差异,表明Sr标记对供试鱼无不良影响.由于耳石上清晰、完整的高Sr红色标记环带出现在标记浓度为8 mg·L-1及以上,标记时间为2 d及以上,故建议分别选择8 mg·L-1和2 d为基本浸泡标记浓度和基本浸泡标记时间.本研究证实耳石Sr标记技术对鲤稚鱼具有很好的可行性.

In this study,we evaluated the effectiveness of SrCl2·6 H2O to mark otoliths of juvenile common carp(Cyprinus carpio).The carp fish were immersed with four concentrations of the Sr compound(i.e.,0,4,8,12 mg·L-1)for 2 d to determine the essential concentration for immersing.Then,the carp fish were immersed in 8 mg·L-1 of the Sr compound for five different immersing times(i.e.,1,2,3,4,5 d)to establish the essential immersing time.Results from electron microprobe analysis(EPMA)showed that otolith Sr marks were very obvious in all C.carpio fish of the aforementioned Sr immersed group with high ratio of Sr/Ca concentration and red color(high Sr level)ring map,compared to the control group with low ratio of Sr/Ca concentration and basic blue color(low Sr level)map.We obtained a 100%mark-success rate of otolith Sr marking in juvenile C.carpio.No significant difference were observed on the average body length,mass and mortality between the immersed group and the control group,suggesting that Sr marking had no negative impact on fish.As clear and complete otolith Sr marked rings occurred at concentration of 8 mg·L-1 or more,and immersing timeof 2 d or more for the Sr compound,8 mg·L-1 and 2 d were suggested as the essential immersing Sr concentration and immersing time,respectively.Our results demonstrated the strong feasibility of otolith Sr marking for juvenile C.carpio.