Lewis Nathaniel S, Young David R, Folger Christina L, DeWitt Theodore H
ORISE Research Fellow, Pacific Coastal Ecology Branch, Pacific Ecological Systems Division, U.S. Environmental Protection Agency, Newport, OR 97365, USA.
Pacific Coastal Ecology Branch, Pacific Ecological Systems Division, U.S. Environmental Protection Agency, Newport, OR 97365, USA.
Estuaries Coast. 2020 Aug 31;44(4):1062-1073. doi: 10.1007/s12237-020-00821-1.
Estuaries serve as important nurseries for many recreationally and commercially harvested fisheries species. Recent conceptual approaches (i.e., seascape) for assessing the value of estuaries to fisheries have advocated for complex habitat-scale assessments that integrate multiple life-history responses (e.g., abundance, growth, reproduction) and ecological processes across heterogeneous landscapes. Although ecologically compelling, implementing seascape approaches may not be feasible for resource-limited management agencies. In such cases, we propose that resource managers can enhance the identification of fishery-important estuarine habitats by integrating attainable aspects of the seascape approach into a more traditional single response (e.g., abundance) model. Using Dungeness crab () as a case study, we applied a spatially-explicit hybrid approach to assess the relative contribution of different estuarine habitats to that important fishery species within three Oregon estuaries (Tillamook, Yaquina, and Alsea bays). We measured the abundance of juvenile from low-tide trawls in estuarine channels and the mosaic of habitat characteristics within defined home-range distances for the crabs. After identifying and reducing strong intercorrelations among habitat variable data, we developed a best-fit model that associated crab abundance with the most influential habitat variables. We found that lower-estuary side channels supported the highest abundance of juvenile crabs; furthermore, crab abundance was positively associated with high salinity and burrowing shrimp () density on adjacent unvegetated tidal flats. This hybrid method produced a habitat-specific model that better predicted juvenile abundance than did a model based on generalized habitat categories.
河口是许多供休闲和商业捕捞的渔业物种的重要育苗场。最近用于评估河口对渔业价值的概念方法（即海景法）主张进行复杂的栖息地尺度评估，该评估整合了多种生活史响应（如丰度、生长、繁殖）以及跨异质景观的生态过程。尽管从生态学角度来看很有说服力，但对于资源有限的管理机构而言，实施海景法可能并不可行。在这种情况下，我们建议资源管理者可以通过将海景法中可实现的方面整合到更传统的单一响应（如丰度）模型中，来加强对渔业重要河口栖息地的识别。以邓杰内斯蟹（）为例，我们应用了一种空间明确的混合方法，来评估俄勒冈州三个河口（蒂拉穆克湾、亚奎纳湾和阿尔西湾）内不同河口栖息地对这种重要渔业物种的相对贡献。我们通过河口航道的低潮拖网测量了幼蟹的丰度，并测量了螃蟹在规定的活动范围内的栖息地特征镶嵌图。在识别并减少栖息地变量数据之间的强相互关系后，我们开发了一个最佳拟合模型，将蟹的丰度与最具影响力的栖息地变量相关联。我们发现河口下游的侧航道幼蟹丰度最高；此外，蟹的丰度与相邻无植被潮滩的高盐度和穴居虾（）密度呈正相关。这种混合方法产生了一个特定栖息地的模型，该模型比基于一般栖息地类别的模型能更好地预测幼蟹的丰度。
