Native Fish Investigations Project, Oregon Department of Fish and Wildlife, Corvallis, Oregon, United States of America.
PLoS One. 2012;7(5):e37257. doi: 10.1371/journal.pone.0037257. Epub 2012 May 24.
From 1997 to 2004, we used radio telemetry to investigate movement and distribution patterns of 206 adult fluvial bull trout (mean, 449 mm FL) from watersheds representing a wide range of habitat conditions in northeastern Oregon and southwestern Washington, a region for which there was little previous information about this species. Migrations between spawning and wintering locations were longest for fish from the Imnaha River (median, 89 km) and three Grande Ronde River tributaries, the Wenaha (56 km) and Lostine (41 km) rivers and Lookingglass Creek (47 km). Shorter migrations were observed in the John Day (8 km), Walla Walla (20 km) and Umatilla river (22 km) systems, where relatively extensive human alterations of the riverscape have been reported. From November through May, fish displayed station-keeping behavior within a narrow range (basin medians, 0.5-6.2 km). Prespawning migrations began after snowmelt-driven peak discharge and coincided with declining flows. Most postspawning migrations began by late September. Migration rates of individuals ranged from 0.1 to 10.7 km/day. Adults migrated to spawning grounds in consecutive years and displayed strong fidelity to previous spawning areas and winter locations. In the Grande Ronde River basin, most fish displayed an unusual fluvial pattern: After exiting the spawning tributary and entering a main stem river, individuals moved upstream to wintering habitat, often a substantial distance (maximum, 49 km). Our work provides additional evidence of a strong migratory capacity in fluvial bull trout, but the short migrations we observed suggest adult fluvial migration may be restricted in basins with substantial anthropogenic habitat alteration. More research into bull trout ecology in large river habitats is needed to improve our understanding of how adults establish migration patterns, what factors influence adult spatial distribution in winter, and how managers can protect and enhance fluvial populations.
从 1997 年到 2004 年，我们使用无线电遥测技术调查了来自俄勒冈州东北部和华盛顿州西南部的 206 条成年河鳟（平均 449 毫米 FL）的运动和分布模式，这些流域代表了该物种以前很少有信息的广泛栖息地条件。来自因马哈河（中位数为 89 公里）和格兰德朗德河三条支流——韦纳哈河（56 公里）、洛斯丁河（41 公里）和利克格斯克里克（47 公里）的鱼类洄游到产卵地和越冬地的距离最长。在约翰迪河（8 公里）、瓦拉瓦拉河（20 公里）和乌马蒂拉河（22 公里）系统中，观察到的迁徙距离较短，这些河流的景观已经受到了广泛的人为改变。从 11 月到 5 月，鱼类在一个狭窄的范围内保持在一个固定的位置（流域中位数为 0.5-6.2 公里）。产卵洄游在融雪驱动的峰值流量后开始，并与流量下降相吻合。大多数产卵后洄游在 9 月下旬开始。个体的迁徙速度从 0.1 到 10.7 公里/天不等。成年鱼连续几年洄游到产卵地，并对以前的产卵区和越冬地表现出强烈的忠诚度。在格兰德朗德河流域，大多数鱼类表现出一种不寻常的河流模式：离开产卵支流并进入干流后，个体向上游迁徙到越冬栖息地，通常距离很远（最大距离为 49 公里）。我们的工作为河鳟具有很强的洄游能力提供了额外的证据，但我们观察到的短距离迁徙表明，在有大量人为栖息地改变的流域，成年河鳟的洄游可能受到限制。需要对大河流域的虹鳟生态学进行更多研究，以提高我们对成年鱼如何建立洄游模式、影响冬季成年鱼空间分布的因素以及管理者如何保护和增强河流种群的理解。
