茜素络合物对半滑舌鳎(Cynoglossus semilaevis)苗种耳石的染色标记效果

采用茜素络合物(Alizarin Complexone,ALC)分别浸泡标记70 d和170 d半滑舌鳎(Cynoglossus semilaevis)苗种耳石,设置了5个浓度组和3个时间梯度组.结果显示,ALC对半滑舌鳎70-170 d苗种的耳石染色效果明显.综合考虑存活率和标记效果,ALC浸泡标记半滑舌鳎苗种耳石的适宜浓度为100 mg/L (36 h浸泡处理)和150 mg/L(24 h浸泡处理).相同浸泡时间下,随着ALC浓度的增加,耳石上标记信号强度增加,但实验鱼死亡率升高;相同浸泡浓度下,随着时间的增加,耳石上标记信号强度增加,实验鱼死亡率也会升高.对标记的170d苗种进行养殖实验,每30 d取样矢耳石进行观察,发现4个月后实验鱼生长良好,且耳石荧光信号仍可清晰检测到,表明ALC在半滑舌鳎矢耳石上形成的荧光标记可长期存续,标记效果好.研究结果可为半滑舌鳎大规模标志放流及早期生活史研究提供群体身份识别技术支持.

Alizarin Complexone Marking of Otoliths of Juvenile Cynoglossus semilaevis

As a result of the scaled stock enhancement of tongue sole, Cynoglossus semilaevis, since 2006 in China, millions of juveniles were released into the Bohai Sea and the Yellow Sea annually. However, it is difficult to evaluate the effectiveness of this operation because of a lack in efficient marking techniques. Here we tested the potential of alizarin complexone (ALC) as a marking material on tongue sole otolith. ALC solutions with 5 concentrations ranging from 0 to 200 mg/L in undiluted seawater were prepared. One hundred tongue sole juveniles of two sizes (70 d and 170 d post hatching) were randomly assigned into the 5 groups of ALC solutions and in each group the subjects were immersed into the solution for 12 hours, 24 hours, and 36 hours. Duplication was performed for each group. The results showed strong markings with ALC on otoliths of tongue soles. The optimal concentrations of ALC were 100 mg/L for 36-h marking and 150 mg/L for 24-h marking, which ensured both sound survival rate and strong marking signals. The marking quality (MQ) was assessed with scores from 0 to 3, and a score > 2 was regarded acceptable for adequate mark identification. The marking signals on the otolith were enhanced as the solution concentration increased, which however also increased the mortality rate. The marked juveniles (170 d) were cultured in indoor tanks for 4 months to determine how long the ALC marking could last. The marking signals were still clear at the end of the culture, and there was no difference in the growth between marked and unmarked subjects with the same size. These results indicated that ALC could form lasting signals on otoliths of tongue soles, and thus may be a useful tool in the evaluation of stock enhancement and the identification of tongue sole populations.