Spatial and interannual variability of seascape and micronekton assemblage associations in the California Current Ecosystem

Dynamic seascapes, which are classified using a combination of remotely sensed and in-situ data, represent both an innovation in ocean observation and a potential tool for dynamic ecosystem-based management in marine systems. Our study explores the utility of seascape classification in the context of micronekton species assemblages and identifies distinct seascape classes across a range of spatial and temporal scales. Seascapes represent distinct phytoplankton assemblages and physical heterogeneity. If micronekton assemblage patterns are structured by physical circulation and planktonic prey abundances, species and assemblage level associations with specific seascapes should emerge, which would be useful for ecosystem monitoring. Annual catch per unit effort data were collected using mid-water trawls off central California from 2004-2015, resulting in >1300 trawls that captured ~150 species. Multivariate statistics were used to identify spatio-temporal patterns and quantify significant relationships between seascapes, assemblage structure, and individual species abundances. Initial results suggest that relationships between seascape classes and forage fish abundance vary interannually and may depend on broad-scale changes of oceanographic conditions and species abundance. Increased seascape classification resolution and additional analyses on micronekton functional ecology and seascape boundary effects will improve our ability to understand and predict forage species/habitat associations. We anticipate that applying seascape methodology to ecosystem-scale studies of pelagic communities will provide valuable information to resource managers, recreational and commercial fisheries, policymakers, and other end-users.