Thorson James T, Rindorf Anna, Gao Jin, Hanselman Dana H, Winker Henning
Fisheries Resource Assessment and Monitoring Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA, USA
DTU Aqua National Institute of Aquatic Resources, Technical University of Denmark (DTU), Jægersborg Alle 1, Charlottenlund Castle, 2920 Charlottenlund, Denmark.
Proc Biol Sci. 2016 Oct 12;283(1840). doi: 10.1098/rspb.2016.1853.
The spatial distribution of marine fishes can change for many reasons, including density-dependent distributional shifts. Previous studies show mixed support for either the proportional-density model (PDM; no relationship between abundance and area occupied, supported by ideal-free distribution theory) or the basin model (BM; positive abundance-area relationship, supported by density-dependent habitat selection theory). The BM implies that fishes move towards preferred habitat as the population declines. We estimate the average relationship using bottom trawl data for 92 fish species from six marine regions, to determine whether the BM or PDM provides a better description for sea-bottom-associated fishes. We fit a spatio-temporal model and estimate changes in effective area occupied and abundance, and combine results to estimate the average abundance-area relationship as well as variability among taxa and regions. The average relationship is weak but significant (0.6% increase in area for a 10% increase in abundance), whereas only a small proportion of species-region combinations show a negative relationship (i.e. shrinking area when abundance increases). Approximately one-third of combinations (34.6%) are predicted to increase in area more than 1% for every 10% increase in abundance. We therefore infer that population density generally changes faster than effective area occupied during abundance changes. Gadiformes have the strongest estimated relationship (average 1.0% area increase for every 10% abundance increase) followed by Pleuronectiformes and Scorpaeniformes, and the Eastern Bering Sea shows a strong relationship between abundance and area occupied relative to other regions. We conclude that the BM explains a small but important portion of spatial dynamics for sea-bottom-associated fishes, and that many individual populations merit cautious management during population declines, because a compressed range may increase the efficiency of harvest.
海洋鱼类的空间分布会因多种原因而改变，包括密度依赖型分布转移。先前的研究对比例密度模型（PDM；丰度与占据面积之间无关系，由理想自由分布理论支持）或流域模型（BM；丰度与面积呈正相关关系，由密度依赖型栖息地选择理论支持）的支持情况不一。BM意味着随着种群数量下降，鱼类会向偏好的栖息地移动。我们利用来自六个海洋区域的92种鱼类的底拖网数据估计平均关系，以确定BM还是PDM能更好地描述与海底相关的鱼类。我们拟合了一个时空模型，估计有效占据面积和丰度的变化，并结合结果来估计平均丰度 - 面积关系以及分类群和区域之间的变异性。平均关系较弱但显著（丰度增加10%时面积增加0.6%），而只有一小部分物种 - 区域组合呈现负相关关系（即丰度增加时面积缩小）。大约三分之一的组合（34.6%）预计丰度每增加10%，面积增加超过1%。因此，我们推断在丰度变化期间，种群密度的变化通常比有效占据面积的变化更快。鳕形目鱼类的估计关系最强（丰度每增加10%，平均面积增加1.0%），其次是鲽形目和鲉形目，与其他区域相比，白令海东部的丰度与占据面积之间呈现出很强的关系。我们得出结论，BM解释了与海底相关鱼类空间动态中虽小但重要的一部分，并且在种群数量下降期间，许多个体种群值得谨慎管理，因为分布范围压缩可能会提高捕捞效率。
