In spite of this variability, we contend that bathymetric associations of upper trophic-level predators can help delineate sites of elevated trophic transfer.
This paper presents a thorough description of the model itself, as well as an ensemble-based parameterization process that allows the model to incorporate the high level of uncertainty associated with many upper trophic level predator-prey processes.
We also excluded any information on species presence based on gut content analysis of upper trophic level predators sampled within our census area.
We excluded certain taxonomic groups, namely pelagic zooplankton and upper trophic level predators, such as marine mammals (whales, dolphins, seals) and large predatory or highly migratory species (swordfish, tunas, turtles, jellyfish and siphonophores), due to their transient, anecdotal, or unconfirmed presence within our sub-regions.
Given their status as upper trophic-level predators foraging over vast areas of the subantarctic and Antarctic oceanic zone, variation in abundance and life history parameters in this species may be indicative of larger changes occurring throughout the Antarctic ecosystem [ 21].
It biomagnifies in aquatic food chains where "nearly 100% of the mercury that bioaccumulates in upper-trophic-level fish (predator) tissue is methylmercury" [ 13].
Upper trophic-level marine predators such as seabirds and seals are particularly amenable to the examination of such mechanistic hypotheses because they are easily monitored during their obligatory onshore breeding phase [ 21].
Fishing impacts on biodiversity include severe reductions in upper-trophic-level predators and cascading responses through lower parts of the food web [53], [54], [55].
Upper-level trophic predators, including seabirds, are commonly used as indicators for ecosystem monitoring [e.g. 101], [102], [103] and fish stock assessment [e.g. 104].
Predators occupy the upper levels of food chains.
