Seventy years of diminishing biocomplexity of California Central Valley hatchery steelhead, Oncorhynchus mykiss
Seventy years of diminishing biocomplexity of California Central Valley hatchery steelhead, Oncorhynchus mykiss
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DOI：
10.1139/cjfas-2023-0077
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发表时间：
2024-02-02
影响因子：
2.4
通讯作者：
Carlson，Stephanie M.
中科院分区：
文献类型：
--
作者：
Huber，Eric R.;Ryan，Rachael E.;Carlson，Stephanie M.
自欧美殖民以来，加州中央谷钢头鱼（Oncorhynchus mykiss）数量急剧下降，自1998年以来已被美国濒危物种法案列为受威胁物种。孵化场来源的鱼现在占主导地位，孵化场管理是一个关键的因素。然而，缺乏可用的发布度量信息。我们编制了o的时间序列。所有四个中央谷地孵化场的数据。1948年至2017年间的接吻。自20世纪80年代初以来，放生鱼类的生物复杂性一直在下降。随着时间的推移，个体以越来越相似的数量、生物量、体型、时间和地点被释放。此外，自20世纪90年代末和21世纪初以来，一岁的幼鱼已经以更大的尺寸被释放，导致几乎只在2月和3月释放1岁的幼鱼。在环太平洋地区的其他孵化场支持的太平洋鲑鱼种群中，释放组合的普遍减少可能已经发生。在一个日益变化的环境中，种内多样性的减少可能会显著影响种群的稳定性和恢复力。
The California Central Valley steelhead (Oncorhynchus mykiss) has declined precipitously since Euro-American colonization and has been listed as threatened under the United States Endangered Species Act since 1998. Hatchery-origin fish now dominate the population, and hatchery management is a key listing factor. However, scant release metric information is available. We compiled a time series ofO. mykisshatchery release data for all four Central Valley hatcheries releasingO. mykissbetween 1948 and 2017. The biocomplexity of released fish has declined since the early 1980s. Individuals have been released at increasingly similar numbers, biomass, body sizes, times, and locations over time. Moreover, yearling fish have been released at larger sizes, leading to the near-exclusive release of age-1 smolts in February and March since the late 1990s and early 2000s. Pervasive reductions in release portfolios have likely occurred for other hatchery-supported Pacific salmonid stocks throughout the Pacific Rim region. In an increasingly variable environment, such reductions in intraspecific diversity could significantly affect population stability and resilience.