Abstract

Biotelemetry of Atlantic sturgeon Acipenser oxyrinchus oxyrinchus has exposed spawning behaviors in ever-smaller estuaries, surprising for the NW Atlantic’s largest anadromous species. Small estuary — the Nanticoke River and Marshyhope Creek (Chesapeake Bay) — spawning-run adults and their habitat affinities are described based upon direct sampling and biotelemetry for the period 2014–2018. High rates of recapture over this period indicate a very small adult population size. Genetics revealed a very small effective population size (N_e = 12.2, 95% CI = 6.7–21.9). Most returns occurred during September at 20–27 °C. All fish departed as fall temperatures declined below 20 °C. Multi-beam sonar identified small-dispersed areas of sand-cobble and cobble, which could support adhesive embryo attachment. Movements of adults were higher during nighttime than daytime, with habitat preference for hard bottom habitats. Genetic evidence indicates that the sudden discovery of this population was unrelated to a hatchery release of several thousand juvenile sturgeon (Hudson River progeny) in 1997. The newly discovered population in the Nanticoke River exhibits a degree of resilience including multiple spawning regions and suitable spawning habitat. Still, critical vulnerabilities persist including curtailed habitat, continued agricultural and maritime development, invasive blue catfish, and a very small apparent population size.

Supplemental data for this article is available online at https://doi.org/10.1080/23308249.2021.1924617

摘要

大西洋鲟鱼Acipenser oxyrinchus oxyrinchus的生物遥测揭示了在越来越小的河口的产卵行为，这对于西北大西洋最大的溯河物种来说是令人惊讶的。基于 2014-2018 年期间的直接采样和生物遥测，描述了小型河口——南蒂科克河和 Marshyhope 溪（切萨皮克湾）——产卵的成虫及其栖息地亲缘关系。这一时期的高重新捕获率表明成年人口规模非常小。遗传学揭示了一个非常小的有效种群规模（N _e= 12.2, 95% CI = 6.7–21.9)。大多数回归发生在 9 月，温度为 20-27°C。随着秋季气温降至 20 °C 以下，所有鱼都离开了。多波束声纳识别了沙砾和鹅卵石的小分散区域，这可以支持粘附胚胎附着。成虫在夜间的活动高于白天，栖息地偏爱硬底栖息地。遗传证据表明，这一种群的突然发现与 1997 年数千只幼年鲟鱼（哈德逊河后代）的孵化场释放无关。南蒂科克河中新发现的种群表现出一定程度的复原力，包括多个产卵区和合适的产卵栖息地. 尽管如此，严重的脆弱性仍然存在，包括栖息地减少、农业和海洋发展持续、蓝鲶入侵、

本文的补充数据可在线获取 https://doi.org/10.1080/23308249.2021.1924617