Acoustic seascape partitioning through functional data analysis

Aim Water column acoustic backscatter is regularly registered during oceanographic surveys, providing valuable information on the composition and distribution of pelagic life in ocean. We propose an objective approach based functional data analysis to classify these seascapes into biogeographical regions. Location Tropical South Atlantic Ocean off northeastern Brazil. Taxon Sound-scattering fauna detected with echosounders, principally small fish, crustaceans, squid diverse gelatinous life-forms. Methods use as a function depth, simultaneously at three frequencies, numerically describe vertical sound-scattering organisms water column. This used seascape through principal component analysis. The routine tested illustrated collected 38, 70 120 kHz waters affected by contrasting environmental conditions. Results Acoustic partitioning mirrored current systems, fronts taxonomically regionalization. study area was divided between slope-boundary open-ocean waters, spring fall hydrological regimes. Main Conclusions consistency spatiotemporal coherence regions classified show that method efficient identifying homogeneous cohesive communities. Comparisons against biological regionalization prove reliable delineating distinct ecosystems cost-efficient non-intrusive way.