基于投喂法的牙鲆耳石锶标记

Use of Strontium Chloride in Otolith Marking of Japanese Flounder

中文关键词: 锶标记  耳石  牙鲆

英文关键词: Strontium marking  Otolith  Japanese flounder

中文摘要:

      本研究首次采用投喂标记饲料的方法，对牙鲆(Paralichthys olivaceus)耳石锶(Sr)标记进行研究。实验组设置1、8、64 g/kg (SrCl2ˑ6H2O/饲料) 3个梯度，无SrCl2ˑ6H2O添加饲料为对照组，投喂标记饲料10 d，再养殖30 d后采样。利用EPMA对样本的矢耳石进行线性定量和面分析，检测耳石Sr标记效果。结果显示，8、64 g/kg实验组耳石均出现Sr标记。8 g/kg组耳石Sr标记峰值为对照组的2倍，64 g/kg组耳石Sr标记峰值较对照组分别高6倍和18倍，Sr标记峰值随着标记饲料浓度增加而增大。对各梯度组生长研究发现，1、8 g/kg梯度组全长分别为(11.11±1.32) cm和(10.88±1.07) cm，差异不显著(P>0.05)，1、8 g/kg梯度组与0、64 g/kg梯度组全长差异显著(P<0.05)，说明摄食适量Sr元素，可促进鱼体生长。标记期间，各梯度组均未出现实验鱼死亡，表明Sr元素对牙鲆安全无毒。本研究为海水鱼类耳石元素指纹标记探索了新的标记途径，为科学进行牙鲆增殖放流效果评估积累了参考资料。

英文摘要:

      In the management of stock enhanced Japanese flounder, it is often necessary to distinguish those that are hatchery-reared, from wild stocks. This study examines the feasibility of marking Japanese flounder by feeding them a diet enriched with strontium. To achieve nominally different concentrations of strontium in the fish food, 1, 8, and 64 g of strontium chloride crystals (SrCl2∙6H2O) were each dissolved in 1 L of distilled water and sprayed onto 1 kg of pelleted feed. The treatments groups of fish were fed the pellets for 10 d, then farmed for 30 days, and then sampled. Our data shows that both the 8 g SrCl2/kg feed and 64 g SrCl2/kg feed resulted in a mark on the otoliths of the Japanese flounder. The peak concentration of strontium (8 g SrCl2/kg), often resulted in otoliths with concentrations two orders of magnitude higher than those found in the control fish. The concentration of strontium in the 64 g SrCl2/ kg feed, resulted in a 6-fold or 18-fold increases in the otoliths. The strontium value increased with the increased concentration of strontium in the pellet feed. The results also showed that strontium was safe for the fish and did not negatively affect their mortality. The total body length of the treatment groups with 1 and 8 g SrCl2/kg, were (11.11±1.32) cm and (10.88±1.07) cm, respectively, in which the length growth rate was faster than that of the control group and the treatment group with 64 g SrCl2/kg feed (P≤0.05). With appropriate strontium concentrations, the growth of the Japanese flounder youth was enhanced. Our results suggest that feeding a diet enriched in strontium could be an effective means of marking hatchery-reared Japanese flounder for stock enhancement.