Merten, VéroniqueGuilpin, MarieParker, JuliaOudejans, MachielDolan, ShannonBaumann-Pickering, SimoneHazen, ElliottBarcelos, LuísGuerreiro, Miguel FernandesPorteiro, FilipeFranzenburg, SörenBayer, TillHoving, Henk-JanVisser, Fleur2026-05-132026-05-132026-05-11Merten, V., Guilpin, M., Parker, J. M., Oudejans, M., Dolan, S. M., Baumann-Pickering, S., Hazen, E. L., Barcelos, L. M. D., Guerreiro, M. F., Porteiro, F. M., Franzenburg, S., Bayer, T., Hoving, H. & Visser, F. (2026). The Deep-Sea Preyscapes of Mammalian Top Predators. Environmental DNA, 8(3), e70296.2637-4943http://hdl.handle.net/10400.3/8956Prey richness, accessibility, and density shape predator foraging strategies. Deep-sea preyscapes, however, remain largely unknown, limiting our understanding of how prey presence and distribution shape predator movement, energy budget, and ecological role. Using combined eDNA metabarcoding and hydroacoustics, we investigated the deep-sea cephalopod and fish preyscapes of three co-occurring cetacean predators (Risso's dolphins (Grampus griseus), Sowerby's beaked whales (Mesoplodon bidens), and goose-beaked whales (Ziphius cavirostris)) across an inshore-offshore gradient. We tested whether (i) prey acoustic backscatter (a metric for density) and taxonomic richness decreased with distance from shore; (ii) predators exploit localized peaks in prey density and richness; and (iii) prey composition and density varied across adjacent foraging habitats along the inshore-offshore gradient. Across 117 samples, we detected 37 cephalopod and 66 fish taxa, including other top predators (sharks). Acoustic backscatter was concentrated within the deep scattering layer (DSL). Yet, peak taxonomic richness occurred above and below it, suggesting that the local DSL holds relatively limited fish and cephalopod richness. The offshore DSLs were vertically shallower and more stable, while the inshore DSL was deeper and bifurcated, possibly due to predator avoidance. Contrary to expectation, acoustic backscatter offshore was up to fivefold higher than inshore, and taxonomic richness did not decrease with distance from shore. Fish communities varied primarily with depth, whereas cephalopod communities varied along the inshore-offshore gradient. Bathypelagic offshore foraging zones of goose-beaked whales contained overall low acoustic backscatter but high taxonomic richness. This suggests that goose-beaked whales may target large, energy-rich cephalopods and prioritize prey quality over density. Our results reveal vertical and horizontal habitat complexity in an oceanic ecosystem that may shape predator–prey interactions and habitat partitioning among cetacean species.engcephalopodscetaceansdeep-sea acoustic backscatterdeep-sea preyscapedeep-sea richnesseDNAfishresearch article10.1002/edn3.70296