Age and growth estimates of bowhead whales (Balaena mysticetus) via aspartic acid racemization
Age and growth estimates of bowhead whales (Balaena mysticetus) via aspartic acid racemization
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DOI：
10.1139/cjz-77-4-571
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发表时间：
1999-04-01
影响因子：
1.4
通讯作者：
Suydam, R
中科院分区：
文献类型：
--
作者：
George, JC;Bada, J;Suydam, R
共收集和分析了48个眼球，以估计年龄的弓头鲸使用天冬氨酸消旋技术。在这项技术中，年龄估计的基础上的内在变化的D和L对映异构体形式的天冬氨酸在眼睛透镜核。42只动物的年龄估计成功。天冬氨酸的外消旋速率（k（Asp））是基于早期对人类和长须鲸的研究数据;使用的估计值为1.18 x 10（-3）/年。使用小于或等于2岁的动物（n = 8）估计出生时D/L比（（D/L）（0）），因为D/L测量值的变异性足够大，无法测量该范围内年龄间的差异。（D/L）（0）估计值为0.0285。年龄估计值的方差采用delta方法获得。根据这些数据，女性的生长似乎比男性快，性成熟年龄（男性身长12-13米，女性身长13-13.5米）出现在25岁左右。这两个6岁的人在大约40-50岁时生长速度明显放缓。4人（均为男性）超过100岁。标准误差随着估计年龄的增加而增加，但年龄估计值对老年动物的变异系数较低。从最近捕获的五头鲸鱼身上发现的传统捕鲸工具也表明，在某些情况下，鲸鱼的寿命超过100岁。
A total of 48 eye globes were collected and analyzed to estimate ages of bowhead whales using the aspartic acid racemization technique. In this technique, age is estimated based on intrinsic changes in the D and L enantiomeric isomeric forms of aspartic acid in the eye lens nucleus. Age estimates were successful for 42 animals. Racemization rate (k(Asp)) for aspartic acid was based on data from earlier studies of humans and fin whales; the estimate used was 1.18 x 10(-3)/year. The D/L ratio at birth ((D/L)(0)) Was estimated using animals less than or equal to 2 years of age (n = 8), since variability in the D/L measurements is large enough that differences among ages in this range are unmeasurable. The (D/L)(0) estimate was 0.0285. Variance of the age estimates was obtained using the delta method. Based on these data, growth appears faster for females than males, and age at sexual maturity (age at length 12-13 m for males and 13-13.5 m for females) occurs at around 25 years of age. Growth slows markedly for both sixes at roughly 40-50 years of age. Four individuals (all males) exceed 100 years of age. Standard error increased with estimated age, but the age estimates had lower coefficients of variation for older animals. Recoveries of traditional whale-hunting tools from five recently harvested whales also suggest life-spans in excess of 100 years of age in some cases.