Assessment of the Importance of Coastal Pelagic Species in the Ecosystem Variability of the California Current

Current Status of Accomplishment or Milestone: Completed.

Background: NMFS is currently in the early stages of moving to ecosystem-based analyses and management. The California Current (CC) is known to have extensive regime-scale environmental variability that will heavily impact ecosystem management. Modeling of CC species has largely been dominated by traditional fishery models, which have no geographical resolution, no environmental forcing and no quantification of relationships to other trophic levels. A dramatic decline in the biological production of the CC ecosystem has occurred over the past several decades; however, several important migratory species, including the system’s dominant forage fish (sardine) have exhibited increased productivity. The PFEL fishery and environmental programs are now starting to provide the information necessary to predict/explain the productivity of information-rich species under differing environmental conditions.

Purpose of Activity/Goal of Project: Develop an ecosystem model describing the productivity of the sardine and its geographical importance as forage for higher trophic levels in differing environmental regimes.

Description of Accomplishment and Significant Results: This analysis has produced an ecosystem model describing the regional distribution, forage contribution and productivity of the sardine in differing environmental conditions. The model provides an explanation of the observed increase in sardine productivity during a multi-decadal period of reduced zooplankton levels. This increased sardine productivity is shown to be due to the sardine’s migratory behavior and temperature preferences, which allow the population to be centered at higher, more productive latitudes during periods with warm sea surface temperature. The model’s forage component shows that a 1 MMT sardine population produces more than 0.7 MMT of forage.

Significance of Accomplishment (e.g., to the Center, to Management, and to NMFS Strategic plan Goals): This analysis has produced a geographically distinct ecosystem model of the dominant coastal pelagic fish in the California Current Ecosystem. The model provides estimates of the productivity of sardine in different environmental conditions and it uses observed environmental conditions to predict the seasonal geographical distribution of sardine.

Finally, the model is designed to use Global Climate Change model output to assess the productivity and geographical distribution of sardine under predicted Climate Change Scenarios.

Problems: None.

Key Contact: Richard Parrish (831-648-9033, Richard.Parrish@noaa.gov)