Human impacts (e.g., fishing, pollution, and shipping) on pelagic ecosystems are increasing, causing concerns about stresses on marine food webs. Maintaining predator-prey relationships through protection of pelagic hotspots is crucial for conservation and management of living marine resources. Biotic components of pelagic, plankton-based, ecosystems exhibit high variability in abundance in time and space (i.e., extreme patchiness), requiring investigation of persistence of abundance across trophic levels to resolve trophic hotspots. Using a 26-yr record of indicators for primary production, secondary (zooplankton and larval fish), and tertiary (seabirds) consumers, we show distributions of trophic hotspots in the southern California Current Ecosystem result from interactions between a strong upwelling center and a productive retention zone with enhanced nutrients, which concentrate prey and predators across multiple trophic levels. Trophic hotspots also overlap with human impacts, including fisheries extraction of coastal pelagic and groundfish species, as well as intense commercial shipping traffic. Spatial overlap of trophic hotspots with fisheries and shipping increases vulnerability of the ecosystem to localized depletion of forage fish, ship strikes on marine mammals, and pollution. This study represents a critical step toward resolving pelagic areas of high conservation interest for planktonic ecosystems and may serve as a model for other ocean regions where ecosystem-based management and marine spatial planning of pelagic ecosystems is warranted.

Quantifying spatiotemporal dynamics of ecosystem services is an emerging approach for informing and managing trade-offs among cumulative or competing activities in marine environments. As one proxy for ecosystem services and benefits, we quantified and mapped catch and economic value of California commercial fisheries removals using a 75-year spatially explicit time series. From 1931 to 2005, approximately 88% of the catch was attributed to finfish. However, there has been an increasing reliance of proportional value from invertebrates over the last 25 years. The spatial organization of historical catches suggests species composition varies substantially by depth and latitude, and an evaluation of changes in the spatial distribution of catches in three different time periods suggests that spatial shifts in catch locations have occurred for some taxonomic groups over time. A spatial assessment of historical catches and value benefits marine spatial planning, informs stock assessments, provides a quantification of ecosystem services, and facilitates ecosystem-based approaches to marine fisheries management.