The Salinas River receives inputs from extensive farmlands before flowing into the Salinas River National Wildlife Refuge and the Monterey Bay National Marine Sanctuary (CA, USA). Previous monitoring using laboratory toxicity tests and chemical analyses identified toxic agricultural drain-water inputs in this system. Using caged daphnids (Ceriodaphnia dubia) and amphipods (Hyalella azteca), we investigated in situ toxicity at stations downstream from an agricultural drain relative to a reference station. A flow sensor indicated highly variable inputs from irrigation, and daily synoptic chemical analyses using enzyme-linked immunosorbent assay techniques demonstrated fluctuating concentrations of organophosphate pesticides. Test organism mortality in the field coincided with contaminant concentrations that exceeded chemical effect thresholds for the test species. Laboratory toxicity tests using C. dubia were comparable to results from field exposures, but tests with H. azteca were not. Laboratory exposures can be reasonable surrogates for field evaluations in this system, but they were less effective for assessing short-term temporal variability. Results from the field toxicity studies corroborated results of bioassessment surveys conducted as part of a concurrent study. Toxicity identification evaluations indicated that organophosphate pesticides caused toxicity to daphnids and that effects of suspended solids were negligible.

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.