Recent research suggests that calcified eyestalks and gastric mill ossicles (stomach teeth) can be used to estimate the age of some crustacean species. Along with annual growth of the endocuticle, bipartite bands in the hard tissue are believed to reflect annual growth patterns (similar to fish scales or otoliths) that are retained through repeated molt cycles. Similar bands are observed in the zygocardiac ossicles of the gastric mill from the snow crab (Chionoecetes opilioFabricius 1788). If these bands reflect annual growth, they may be used to estimate age, which could enhance understanding growth, mortality, recruitment, and age composition and improve fishery management. While some studies show that the number of bands correlates to other estimates of age for C. opilio, little evidence suggests that bands accumulate annually as growth increments independent of molting. Male C. opilio terminally molt at maturity, after which they can survive for seven years or more. Shell condition, i.e., degree of wear and epibionts on their exoskeleton, is used here and by other carcinologists as a proxy for age subsequent to the terminal molt. We estimated band counts and endocuticle thickness from thin sections of the zygocardiac ossicle of terminally molted male C. opilio across a range of shell conditions from a wild, fished stock. We found no differences in band counts (P = 0.41) or endocuticle thickness (P = 0.13) across varying shell conditions and size. These results do not support the hypothesis that band counts can be used to estimate the age of this species after the terminal molt.

中文翻译：

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最终蜕皮雄性雪蟹Chionoecetes opilio（Fabricius 1788）的直接年龄估算方法的评估（十足目：Brachyura：Oregoniidae）

最近的研究表明，钙化的眼柄和胃小骨（胃齿）可用于估计某些甲壳类动物的年龄。随着内膜的年生长，硬组织中的二分带被认为反映了通过反复蜕皮循环而保留的年生长模式（类似于鱼鳞或耳石）。从雪蟹（Chionoecetes opilio）在胃磨的合心小骨中观察到相似的条带Fabricius 1788）。如果这些波段反映了年度增长，则可以用来估计年龄，这可以增进对增长，死亡率，征聘和年龄构成的了解，并改善渔业管理。尽管一些研究表明，条带数量与其他对C. opilio的年龄估计相关，但很少有证据表明，条带每年随着积累而增长，与蜕皮无关。男性C. opilio到成熟时最终蜕皮，之后它们可以存活七年或更长时间。在这里以及其他致癌专家使用壳状况，即其外骨骼的磨损程度和表皮生物，作为末蜕之后年龄的替代物。我们估计了野生鱼种在各种壳条件下最终蜕皮的雄性C. opilio合子心小骨的合子心小骨的薄片的带数和表皮厚度。我们发现在不同的壳条件和尺寸下，条带数（P = 0.41）或表皮内膜厚度（P = 0.13）没有差异。这些结果不支持这样的假设，即带状计数可用于估计最终蜕皮后该物种的年龄。