Canadian Journal of Fisheries and Aquatic Sciences, Ahead of Print.
Accurate age data are essential for reliable fish stock assessment. Yet many stocks suffer from inconsistencies in age interpretation. A new approach to obtain age makes use of the chemical composition of otoliths. This study validates the periodicity of recurrent patterns in 25Mg, 31P, 34K, 55Mn, 63Cu, 64Zn, 66Zn, 85Rb, 88Sr, 138Ba, and 208Pb in Baltic cod (Gadus morhua) otoliths from tag–recapture and known-age samples. Otolith P concentrations showed the highest consistency in seasonality over the years, with minima co-occurring with otolith winter zones in the known-age otoliths and in late winter – early spring when water temperatures are coldest in tagged cod . The timing of minima differs between stocks, occurring around February in western Baltic cod and 1 month later in eastern Baltic cod; seasonal maxima are also stock-specific, occurring in August and October, respectively. The amplitude in P is larger in faster-growing western compared with eastern Baltic cod. Seasonal patterns with minima in winter – late spring were also evident in Mg and Mn, but less consistent over time and fish size than P. Chronological patterns in P, and to a lesser extent Mg and Mn, may have the potential to supplement traditional age estimation or to guide the visual identification of translucent and opaque otolith patterns used in traditional age estimation.

中文翻译：

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亲爱的沃森，这很基本：验证耳石化学年表中的季节性模式

《加拿大渔业和水生科学杂志》，印刷前。
准确的年龄数据对于可靠的鱼类种群评估至关重要。然而，许多股票的年龄解释存在矛盾。一种获得年龄的新方法是利用耳石的化学成分。这项研究验证了从标签捕获和已知年龄样品中的波罗的海鳕鱼（加德斯·摩尔瓦）耳石中25Mg，31P，34K，55Mn，63Cu，64Zn，66Zn，65Zn，85Rb，88Sr，138Ba和208Pb的重复模式的周期性。耳石中P的浓度多年来表现出最高的一致性，在已知年龄的耳石中与耳石冬季区域最低共存，而在冬季后期–带标签的鳕鱼中水温最低的初春。不同种群之间的最低值发生时间有所不同，波罗的海鳕鱼的西部地区在2月左右，波罗的海鳕鱼的东部地区在1个月之后。季节性最大值也取决于股票，分别发生在八月和十月。与东部波罗的海鳕鱼相比，生长较快的西部P的振幅更大。冬季-春季后期的季节性模式在Mg和Mn中也很明显，但随时间和鱼类大小的变化不如P。P中的年代学模式以及Mg和Mn的程度较小，可能具有补充传统年龄的潜力估计或指导视觉识别传统年龄估计中使用的半透明和不透明的耳石图案。