大麻哈鱼放流群体耳石温控标记研究

Temperature Regulation Marking on Otolith in Release Populations of Chum Salmon

在大麻哈鱼(Oncorhynchus keta Walbaum)胚胎发育的发眼卵阶段,有规律地改变环境水温,使大麻哈鱼群体耳石日轮出现明暗度、宽窄度等不同的规律性的变化,以标记放流大麻哈鱼群体。试验用发眼后5 d受精卵系吉林省图们江流域大麻哈鱼生殖洄游群体经人工催产所得。按照摩斯密码规则设计CHN和JL两组标记图谱:1组为恒温对照组;2组为CHN标记组;3组为JL标记组;4组为48 h变温组,水温由(11.0±0.5)℃调至起始标记的(8.0±0.5)℃,24 h后调温至(11.0±0.5)℃。高低温转换需在1~2 h内温和过渡。每天记录受精卵死亡数。各组标记结束后均转换至(8.0±0.5)℃,持续24 h,各组抽样20尾观察标记轮。结果显示,除恒温对照组外,CHN组、JL组和48 h变温对照组均出现清晰可辩的标记轮,且与设计图谱一致;标记率100%,死亡率与对照组差异不显著(P>0.05)。本方法标记率高,可辨识度高,成本低和标记死亡率低,适用于大麻哈鱼放流标记。

Otolith thermal marking was conducted in chum salmon(Oncorhynchus keta Walbaum)eyed eggs stage,by regularly changing water temperature,to make the salmon populations otolith different extent of the contrast and width of regular change.The 5-day-old eyed fertilized eggs collected from the reproductive migratory population of the chum salmon in the Tumen River Basin in Jilin Province were divided into two groups CHN and JL labeling maps according to the international general rules of Morse code design:group 1 with a constant temperature control group;group 2 with CHN labeling;group 3 with JL labeling;group 4 with 48h variable temperature,and the water temperature was changed from starting mark(8.0±0.5)℃to(11.0±0.5)℃after 24 h,with a gentle transition temperature conversion within 1~2 h.The marking wheels were observed in 20 individuals sampled from each marking group as water temperature was changed to(8.0±0.5)℃for 24 h,with recording of the death number of eyed eggs.The results showed that with the exception of constant temperature control group,clearly identifiable marking wheels were found in the CHN group,the JL group and the 48 h variable temperature control group,consistent with the design map.It was found that the marking rate was 100%,without significant difference in the mortality rate from the control group.The findings indicated that the method was featured by the advantages of high labeling rate,high identification,low cost and low labeling mortality,and suitable for the reproductive migratory type release populations marking of chum salmon.