滇池鲤4种年龄鉴定材料的比较

为确定鉴定滇池鲤（Cyprinus carpio）年龄的适宜材料，对4种年龄鉴定材料（耳石、鳞片、胸鳍条和鳃盖骨）的形态和年轮标志进行了描述，并对这4种钙化组织鉴定鲤年龄的一致性进行了探讨。2013年5、6、8-11月以及2014年3-7月，使用拖网采集云南滇池鲤584尾，体长范围7.5~50.5 cm，体重范围17.2~3 211.3 g。其中耳石采集于584尾样本，鳃盖骨和鳞片分别采集于276尾样本，胸鳍条采集于274尾样本。微耳石磨片轮纹清晰，在反射光下呈明暗相间的条纹，年龄标志明显。同一鉴定者2次年龄读数的吻合率，微耳石磨片轮最高（88.0%)，鳞片次之(84.1%)，胸鳍条和鳃盖骨则分别为73.7%和72.1%。2次读龄的平均误差百分比，微耳石磨片和鳞片较小，分别为2.6%和2.9%；胸鳍条和鳃盖骨较高，分别为4.7%和5.9%。以微耳石磨片年龄读数为基准，鳞片年龄读数与其吻合率最高(77.5%)，平均变异系数最低(6.14%)；鳃盖骨和胸鳍条与其吻合率分别为61.9%和56.2%，平均变异系数均超过12%。综合分析认为，耳石是滇池鲤年龄鉴定的最佳材料，鉴定4龄以下个体年龄时可使用鳞片，鳃盖骨和胸鳍条则不适于滇池鲤的年龄鉴定。

A Comparative Study of Four Age Validation Structures for Common Carp (Cyprinus carpio) in Dianchi Lake in Yunnan, China

Validation of fish age is the foundation for fish growth and age structure analysis as well as estimating the death rate of a fish population. Calcified structures of fish produce periodic growth increments useful for age determination at the annual scale. Determining proper structures for age validation increases the accuracy and precision of fish aging. The international community of researchers has not reached a consensus on which of the four calcified structures (lapillus, scale, pectoral fin and operculum) is best for determining the age of Cyprinus carpio and all have been used. In China, only scales have been used for Cyprinus carpio aging and some researchers have suggested that pectoral fin and operculum are not suitable for aging Cyprinus carpio. Furthermore, fish growth is influenced by environmental factors which could cause variation in the incremental deposition to the different calcified structures and this should be considered when selecting the most suitable age validation structure. In this paper, we describe the morphology and annuli characteristics of four aging materials (lapillus, scale, pectoral fin and operculum) for common carp in Dianchi Lake of Yunnan province, China. The agreement among the four calcified structures for determining the age of common carp in Dianchi Lake was also analyzed. 584 common carp with body length 7.5-50.5 cm and body weight 17.2-3211.3 g were collected by trawling in Dianchi Lake during May and June and from August to November of 2013, and from March to July of 2014. A total of 584 lapilli specimens, 276 scale specimens, 276 operculum specimens and 274 pectoral fin specimens were prepared and all specimens were observed and photographed under a dissecting microscope. The results show that the incremental deposition on the lapillus of common carp was distinct, demonstrating an obvious alternate opaque zone and translucent zone under reflected light. Among the four structures, the sectioned lapilli showed the highest percentage agreement (88.0%) between duplicate age readings by the same observer, followed by scales (84.1%), pectoral fins (73.7%) and opercula (72.1%). The average percentage error for the duplicate age readings on sectioned lapilli, scales, pectoral fins and opercula were 2.6% and 2.9%, 4.7% and 5.9%, respectively. Furthermore, compared with the age validation by sectioned lapilli, scales showed the highest percentage agreement (77.5%) and the lowest coefficient of variations (6.14%), while opercula and pectoral fin gave only 61.9% and 56.2% percentage agreement with sectioned lapilli. The first annuli of the opercula and pectoral fins were both difficult to confirm and the coefficient of variation for the two materials were both over 12%. To summarize, sectioned lapillus is the best age determination material for common carp in Dianchi Lake. Scales can be used for age determination of individuals less than 4 years old, while opercula and pectoral fins are not suitable for determining the age of common carp.