This study used Ecopath model of the Jiaozhou Bay as an example to evaluate the effect of stomach sample size of three fish species on the projection of this model. The derived ecosystem indices were classified into three categories: (1) direct indices, like the trophic level of species, influenced by stomach sample size directly; (2) indirect indices, like ecology efficiency (EE) of invertebrates, influenced by the multiple prey-predator relationships; and (3) systemic indices, like total system throughout (TST), describing the status of the whole ecosystem. The influences of different stomach sample sizes on these indices were evaluated. The results suggest that systemic indices of the ecosystem model were robust to stomach sample sizes, whereas specific indices related to species were indicated to be with low accuracy and precision when stomach samples were insufficient. The indices became more uncertain when the stomach sample sizes varied for more species. This study enhances the understanding of how the quality of diet composition data influences ecosystem modeling outputs. The results can also guide the design of stomach content analysis for developing ecosystem models.

中文翻译：

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胃内容物分析的样本量对生态系统指数估算的影响

本研究以胶州湾的生态路径模型为例，评估了三种鱼类的胃样大小对该模型投影的影响。得出的生态系统指数分为三类：（1）直接指数，如物种的营养水平，直接受胃样本量的影响；（2）间接指数，例如无脊椎动物的生态效率（EE），受多种食肉动物与食肉动物之间关系的影响；（3）系统指标，例如整个系统（TST），描述了整个生态系统的状况。评估了不同胃样本量对这些指标的影响。结果表明，生态系统模型的系统指标对胃样本量具有鲁棒性，当胃样本不足时，与物种相关的特定指标显示出较低的准确度和精确度。当更多种类的胃样本大小变化时，指数变得更加不确定。这项研究增强了对饮食组成数据质量如何影响生态系统建模输出的理解。结果还可以指导胃内容物分析的设计，以开发生态系统模型。