富锶水体处理对大黄鱼耳石和肌体中锶含量的影响

Effects of strontium-enriched water on strontium content in the otolith and body of hatchery-reared Larimichthys crocea

利用富锶水体处理的大黄鱼(Larimichthy scrocea)耳石元素标记是小规格鱼体规模化标记的一种技术手段,而标记完成后鱼体中的锶残留量是否符合食品食用安全是增殖放流评估中重要一环。通过开展富锶水体对大黄鱼鱼苗的浸泡标记实验,探究受试鱼苗耳石Sr/Ca值对富锶水体标记过程的响应方式,研究耳石元素指纹标记稳定性,分析标记过程对受试鱼苗肌体和主要脏器中锶含量的影响。结果表明:经为期7d、锶浓度含量3倍于天然海水的富锶水体的浸泡标记,受试鱼苗在特定耳石区段的Sr/Ca值显著增大,形成了与对照组个体在该耳石区段Sr/Ca值上的极显著差异(P<0.01);该差异不随时间的推移而减弱,可视做上述处理过程所产生的耳石元素指纹标识。浸泡标记处理后,受试鱼苗肌肉、鳃、肝脏和肾中的锶含量均显著高于对照组(P<0.05)。但随着时间的推移,锶含量逐渐下降;在天然海水中暂养59d后受试鱼苗肌肉和上述脏器中的锶含量均可衰减至对照组的水平。

Through the experiment of immersing juvenile Larimichthys crocea to strontium- enriched water, this research tried to explore the response mode by Sr/Cr values in otoliths of the experimented juvenile Larimichthy scrocea to the process of immersion marker experiment carried out in the strontium-enriched water, to study the stability of the maker of elemental fingerprint in otolith and analyze the changes of strontium content among the organisms and main organs of the tested juveniles.The experiment selected six groups of hatchery-reared juvenile Larimichthys crocea , each group had five thousand juveniles of Larimichthys crocea . Three groups were immersed in strontium-enriched water, and others were used as control groups. Before the experiment, we respectively randomly selected thirty juveniles in six groups. After the experiment, we randomly selected thirty juveniles each time in six groups with totally thirteen times. We used laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) to analyze the strontium-calcium ratio of otolith and the strontium content of organism.The results showed that after seven days’ immersion in the water with strontium concentration 3 times that of the natural ocean water, Sr/Ca value in the otoliths of the tested juveniles increased significantly, leading to an obvious difference from Sr/Ca values in otoliths of Larimichthys crocea in the control group. And this difference did not weaken as time went by, which could be regarded as the otolith fingerprint marker generated by the above mentioned experiment process. After being processed by immersion and marking, the strontium content in the muscles, gills, livers and kidneys in the tested juveniles were all higher than those in the control groups. But as time went by,strontium content decreased gradually and it could drop to the level of the control group after these tested juveniles being fed in the natural ocean water for 59 days.