Current knowledge of age at legal size in Newfoundland & Labrador (NL) and other snow-crab stocks is incomplete due to historic estimations not accounting for skip-molting growth delays. Previous work has shown skip-molting incidence to occasionally be very high in males, both in NL and some other major snow-crab stocks. This warrants research to better understand impacts of skip-molting on snow-crab age and growth dynamics, which are central to population assessment and resource management. We simulated the impact of skip-molting on growth dynamics of snow crabs from three regions around NL by coupling a nineteen year time series of molt-type probabilities derived from field trawl surveys to historical data on age-at-instar based on cohort analysis of wild populations that do not consider skip-molting in making age estimations. Trawl surveys and simulations showed that skip-molting is a prominent feature in NL snow crabs, with up to four skip-molts being a reasonable maximum possible estimate for males in portions of the NL snow-crab stock. A complementary analysis examining the ability to age snow crabs using gastric mill band counts showed overall strong agreement with published growth trajectories that were modified to include skip-molting as well as reasonable average age approximations for most crabs, but unexpectedly high variability in age estimates for individuals of a same instar stage and unexpectedly low age estimates for younger crabs. Our study leads to a refinement of age at legal size for NL snow crab from the current nine-year estimate to a range of 9–13 years. Although this range is deemed to capture virtually every crab reaching legal size in NL snow-crab populations, ages higher than 11 years to fishery recruitment (2 skip-molts) are relatively infrequent.

中文翻译：

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纽芬兰和拉布拉多雪蟹 Chionoecetes opilio (Fabricius, 1788)（十足目：Brachyura：Oregoniidae）的合法大小估计精炼年龄

由于历史估计没有考虑到跳跃蜕皮生长延迟，目前对纽芬兰和拉布拉多（NL）和其他雪蟹种群法定大小年龄的了解并不完整。之前的研究表明，在荷兰和其他一些主要雪蟹种群中，雄性的跳蜕发生率有时非常高。这需要研究来更好地了解跳蜕对雪蟹年龄和生长动态的影响，这对于种群评估和资源管理至关重要。我们通过将田间拖网调查得出的十九年时间序列的蜕皮类型概率与基于队列分析的龄龄历史数据相结合，模拟了跳跃蜕皮对荷兰周围三个地区雪蟹生长动态的影响。在年龄估计时不考虑跳跃蜕皮的野生种群。拖网调查和模拟表明，跳跃蜕皮是荷兰雪蟹的一个显着特征，对于部分荷兰雪蟹种群中的雄性来说，最多四次跳跃蜕皮是合理的最大可能估计。使用胃磨带计数检查雪蟹老化能力的补充分析显示，与已发表的生长轨迹总体上非常一致，该生长轨迹经过修改，包括跳跃蜕皮以及大多数螃蟹的合理平均年龄近似值，但出乎意料的是，同一龄期的个体和年轻螃蟹的年龄估计出乎意料地低。我们的研究将荷兰雪蟹合法大小的年龄从目前的 9 年估计细化为 9-13 年。尽管这个范围被认为捕获了荷兰雪蟹种群中几乎所有达到法定尺寸的螃蟹，但渔业招募年龄超过 11 岁（2 次脱毛）的情况相对较少。