In habitats impacted by bottom trawling that influences the resilience of few and widely distributed abundant species, it is relevant to analyze how populations are structured according to their niche and niche overlap, and hence contributing to the ecosystem-based management approach. We evaluated and compared the isotopic niche width and determined the isotopic niche overlap for target and bycatch species of crustaceans and demersal fish caught with bottom trawling on the continental shelf and upper slope of the central-southern zone of Chile. Stable isotope analysis relied on carbon and nitrogen isotopes (¹³C and ¹⁵N) and Bayesian statistics of niche size and community metrics. Crustaceans and fish species are structured in three clusters according to the stable isotope values and the Chilean hake Merluccius gayi, which was probably clustered isolated due to its pelagic stable isotope values due to diel vertical migrations associated with feeding on euphausiids in the water column. The first group was constituted by demersal fish, that showed higher δ¹⁵N (19‰) and narrower δ¹³C (−16‰). The two other groups constituted a mix of crustaceans and fish, with access to different carbon sources. There were degrees of specialization for most species within the groups and overlap in the isotopic niche between populations. The benthic and demersal macrofauna species are structured by sharing resources in the habitat, probably on available sources supported by the productive pelagic system.

在受底拖网捕捞影响的栖息地中，影响少数和广泛分布的丰富物种的恢复力，有必要根据生态位和生态位重叠来分析种群的结构，从而为基于生态系统的管理方法做出贡献。我们评估和比较了同位素生态位宽度，并确定了在智利中南部大陆架和上坡用底拖网捕捞的甲壳类和底栖鱼类的目标和副渔获物物种的同位素生态位重叠。稳定的同位素分析依赖于碳和氮同位素（¹³ C和¹⁵N）和利基规模和社区指标的贝叶斯统计。甲壳类和鱼类在三个簇根据稳定同位素值和智利鳕结构Merluccius gayi，这很可能是聚集分离由于其上层稳定同位素值由于与在水柱磷虾供给相关联的昼夜垂直迁移。第一组由底层鱼组成，显示较高的δ ¹⁵ N（19‰）和较窄的δ ¹³C (-16‰)。另外两组由甲壳类动物和鱼类组成，可以获取不同的碳源。各组中大多数物种都有专门化的程度，并且种群之间的同位素生态位重叠。底栖和底栖大型动物物种是通过共享栖息地中的资源而构成的，可能是在生产性中上层系统支持的可用资源上共享的。