Predator stomach contents can provide accurate indices of prey biomass

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