Estimating the Effects of Climate Change within the Context of Other Simultaneous Stressors Using the Chesapeake Atlantis Model

Thomas F. Ihde , NOAA Chesapeake Bay Office, ERT, Inc., for NMFS, Annapolis, MD
Howard M. Townsend , Cooperative Oxford Lab, NOAA/NMFS Chesapeake Bay Office, Oxford, MD
Rebecca L. Scott , EcoAnalytics LLC, Cambridge, MD
The Chesapeake Bay and its habitats are important for a variety of managed populations, for spawning, nursery-waters, and for forage. Ultimately, the status of habitats in coastal waters impacts productivity of managed stocks; however, quantifying the connection between these can be difficult. Adding consideration of the multiple effects of climate change is a daunting task, but one that the Atlantis modeling approach is well-suited for. 

Atlantis is a full-system simulation model that integrates available data from multiple disciplines, at multiple scales, and does so within the context of changing system stressors that decision-makers must manage for, like climate change effects, changing fishery harvests, and nutrient management. 

Estimating the effect of any particular system change on production is seldom sufficient in a complex and dynamic system like the Chesapeake, because multiple stressors acting simultaneously on a system can produce non-linear, non-intuitive, cumulative changes, and management actions can produce unforeseen and unintended consequences. 

Current stock assessment focuses on estimating population abundance compared to accepted thresholds, but such efforts may not incorporate cumulative effects of multiple system changes along with changing harvest.  This work begins to fill that gap, providing predictions of productivity in the context of differing assumptions of multiple system stressors.