Portfolio theory as a management tool to guide conservation and restoration of multi-stock fish populations
Portfolio theory as a management tool to guide conservation and restoration of multi-stock fish populations
复制标题
DOI：
10.1890/es15-00237.1
复制
发表时间：
2015-12-01
期刊：
影响因子：
2.7
通讯作者：
Mayer, Christine M.
中科院分区：
文献类型：
--
作者：
DuFour, Mark R.;May, Cassandra J.;Mayer, Christine M.
生境退化和捕捞减少了产卵种群多样性，打乱了许多大型多种群渔业的自然缓冲机制(即组合效应)，而产卵种群多样性对种群稳定和复原力至关重要。投资组合理论的应用提供了一种指导管理活动的手段，通过量化多股票动态的重要性，并建议保护和恢复战略，以改善自然发生的投资组合效果。我们将投资组合理论应用于Erie Sander vitreus(Walleye)，这是一个以河流和开阔湖礁产卵种群为生的大型种群，它表明，与潜在的缓冲能力相比，年度种群间仔鱼产量产生的投资组合效应目前是次优的。河流种群产量的减少导致单一的开阔湖礁种群主导了幼体的生产，进而在最近几年出现了较高的年际补充变异性。我们的分析表明：(1)河流和珊瑚礁的年幼体产量(Rho)在BAR=0.24以上的平均相关性很弱，这表明种群中存在一种天然的缓冲能力；(2)从河流种群中扩大幼体(潜在新兵)的年产量可以通过抑制年际补充变化来稳定渔业。最终，我们的结果表明，如何使用投资组合理论来量化产卵种群多样性的重要性，并在生态相关的规模(即产卵种群)上指导管理，从而提高多种群种群和渔业的稳定性和弹性。
Habitat degradation and harvest have upset the natural buffering mechanism (i.e., portfolio effects) of many large-scale multi-stock fisheries by reducing spawning stock diversity that is vital for generating population stability and resilience. The application of portfolio theory offers a means to guide management activities by quantifying the importance of multi-stock dynamics and suggesting conservation and restoration strategies to improve naturally occurring portfolio effects. Our application of portfolio theory to Lake Erie Sander vitreus (walleye), a large population that is supported by riverine and open-lake reef spawning stocks, has shown that portfolio effects generated by annual inter-stock larval fish production are currently suboptimal when compared to potential buffering capacity. Reduced production from riverine stocks has resulted in a single open-lake reef stock dominating larval production, and in turn, high inter-annual recruitment variability during recent years. Our analyses have shown (1) a weak average correlation between annual river and reef larval production ((rho) over bar = 0.24), suggesting that a natural buffering capacity exists in the population, and (2) expanded annual production of larvae (potential recruits) from riverine stocks could stabilize the fishery by dampening inter-annual recruitment variation. Ultimately, our results demonstrate how portfolio theory can be used to quantify the importance of spawning stock diversity and guide management on ecologically relevant scales (i.e., spawning stocks) leading to greater stability and resilience of multi-stock populations and fisheries.