Abstract Many marine organisms have a biphasic life beginning with a planktonic larva that undergoes development on the continental shelf. These larvae ultimately need to return to the nearshore environment to settle. One proposed mechanism of transport to the nearshore is the internal tide. The Dungeness crab, Metacarcinus (Cancer) magister, is one species that is hypothesized to be transported by the internal tide. In addition to daily cycles in catch of megalopae being correlated with the internal tide, the annual catch of megalopae is correlated with the Pacific Decadal Oscillation. However, intial studies occurred during a positive phase Pacific Decadal Oscillation. In this study, we analyze an additional 12 years of data (16 years total) to determine if the internal tide continues to be correlated with the transport of Dungeness crab megalopae. We used wavelet analyses and cross-Fourier analysis to relate the catch of megalopae to the daily maximum tidal range, wind speed, and sea surface temperature. We found that over 16 years, the correlation with the daily maximum tidal range continues to be the strongest correlate with the daily catch of megalopae. These results continue to suggest megalopae are transported across the continental shelf by the internal tide. Our use of wavelets allowed us to examine the annual trends in periodicity of returning megalopae. We found that the periodicities at tidal frequencies did not persist throughout the settlement season. We hypothesize this indicates cross-shelf transport is primarily regulated by the internal tide but additional, unknown factors, interact with the internal tide affecting the number of returning larvae. We conclude by discussing why high-frequency sampling is an important component of ecological time series.

中文翻译：

---

使用 16 年的每日丰度数据重新审视大闸蟹 (Metacarcinus magister) 通过内部潮汐的跨货架运输

摘要 许多海洋生物从在大陆架上发育的浮游幼虫开始就具有双相生命。这些幼虫最终需要返回近岸环境定居。一种提议的运输到近岸的机制是内部潮汐。Dungeness 蟹，Metacarcinus (Cancer) magister，是一种被假设由内部潮汐运输的物种。除了与内部潮汐相关的巨目动物捕获量的每日周期外，每年的巨目动物捕获量与太平洋年代际振荡相关。然而，最初的研究发生在太平洋年代际振荡的积极阶段。在这项研究中，我们分析了另外 12 年的数据（总共 16 年），以确定内部潮汐是否继续与巨蟹蟹的运输相关。我们使用小波分析和交叉傅立叶分析将巨目动物的捕获量与每日最大潮差、风速和海面温度联系起来。我们发现，16 年来，与每日最大潮汐范围的相关性仍然是与每日捕捞巨目动物的最强相关性。这些结果继续表明巨蜥是通过内部潮汐穿越大陆架的。我们对小波的使用使我们能够检查返回巨藻的周期性的年度趋势。我们发现潮汐频率的周期性并没有在整个定居季节持续存在。我们假设这表明跨货架运输主要受内部潮汐调节，但其他未知因素与影响返回幼虫数量的内部潮汐相互作用。我们最后讨论了为什么高频采样是生态时间序列的重要组成部分。