Diet-based annual biomass indices can potentially use predator stomach contents to provide information about prey biomass and may be particularly useful for species that are otherwise poorly sampled, including ecologically important forage fishes. However, diet-based biomass indices may be sensitive to underlying ecological dynamics between predators and prey, such as predator functional responses and changes in overlap in space and time. To evaluate these factors, we fit spatio-temporal models to stomach contents of five Atlantic herring (Clupea harengus) predators and survey catch data for predators and Atlantic herring. We identified drivers of variation in stomach contents, evaluated spatial patterns in stomach content data, and produced predator-specific indices of seasonal Atlantic herring biomass. After controlling for spatio-temporal processes and predator length, diet-based indices of biomass shared similar decadal trends but varied substantially between predators and seasons on shorter time scales. Diet-based indices reflected prey biomass more than prey availability, but weak correlations indicated that not all biological processes were controlled for. Results provide potential guidance for developing diet-based biomass indices and contribute to a body of evidence demonstrating the utility of predator diet data to provide information about relative prey biomass.

中文翻译：

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捕食者胃内容物可以提供准确的猎物生物量指标

基于饮食的年度生物量指数可以潜在地使用捕食者胃内容物来提供有关猎物生物量的信息，并且可能对否则采样不良的物种特别有用，包​​括具有重要生态意义的饲料鱼。然而，基于饮食的生物量指数可能对捕食者和猎物之间的潜在生态动态敏感，例如捕食者功能反应和空间和时间重叠的变化。为了评估这些因素，我们将时空模型拟合到五种大西洋鲱鱼 (Clupea harengus) 捕食者的胃内容物，并调查捕食者和大西洋鲱鱼的捕获数据。我们确定了胃内容物变化的驱动因素，评估了胃内容物数据的空间模式，并产生了季节性大西洋鲱鱼生物量的捕食者特定指数。在控制时空过程和捕食者长度后，基于饮食的生物量指数具有相似的十年趋势，但在较短的时间尺度上在捕食者和季节之间存在很大差异。基于饮食的指数更多地反映了猎物的生物量而不是猎物的可用性，但相关性较弱表明并非所有的生物过程都受到控制。结果为开发基于饮食的生物量指数提供了潜在的指导，并有助于提供大量证据，证明捕食者饮食数据可用于提供有关相对猎物生物量的信息。但弱相关性表明并非所有生物过程都受到控制。结果为开发基于饮食的生物量指数提供了潜在的指导，并有助于提供大量证据，证明捕食者饮食数据可用于提供有关相对猎物生物量的信息。但弱相关性表明并非所有生物过程都受到控制。结果为开发基于饮食的生物量指数提供了潜在的指导，并有助于提供大量证据，证明捕食者饮食数据可用于提供有关相对猎物生物量的信息。