鲫耳石年轮的观察及其确证

Observation and Validation of Annuli in Otoliths of Carassius auratus

对耳石边缘年轮形成周期进行了分析。结果表明 ,鲫耳石上 1a形成 1个年轮 ,年轮形成时期洪湖种群主要在 4～ 6月 ,洞庭湖种群主要在 3～ 5月。星耳石和微耳石一样 ,可用于鲫年龄鉴定 ,而且不经磨片即可直接读取年轮 ,完整星耳石和微耳石与微耳石磨片上的年轮读数的吻合率均在 80 %以上 ,误差不超过 1龄。但相对而言 ,微耳石上年轮更易观察。

Carassius auratus from Honghu Lake and Dongting Lake were sampled monthly or bimonthly and otoliths were used for age determination. Based on marginal increment analysis, it was demonstrated that the annulus in otoliths was formed once in a year, and the formation periods were from April to June and March to May in Honghu Lake and Dongting Lake, respectively. It was observed that both lapillus and asteriscus could be used to determine the age of Carassius auratus , but the annulus on whole lapillus was relatively easier to detect. The whole otoliths were suitable for direct determination of age, on which readings were 80% above identical with those on the sectioned otoliths and the deviation were within one year. The shapes of both otoliths and the characteristics of annulus are described.