Ivonne Ortiz1,2, and Kerim Aydin2
1UW School of Aquatic & Fishery Sciences
2Alaska Fisheries Science Center
April 19, 2011
The Bering Sea Integrated Research Program (BSIERP) is a 5 year program designed to test hypotheses regarding the ecosystem’s response to climate change. Both historical and BSIERP field data are used to put together a vertically integrated model that includes 5 modules: i) Climate (specific to the Bering Sea), ii) ROMS (Regional Ocean Modeling System) , iii) NPZ-benthos (Nutrient-Phytoplankton-Zooplankton-benthos), iv) FEAST (Forage/Euphausiid Abundance in Space and Time), and v) Economics (fleet movement model). The vertically integrated model in turn, will be used as the “real world” model in a Management Strategy Evaluation for the Bering Sea pollock, and Pacific cod fisheries. We will start with a presentation of the vertically integrated model structure and feedbacks, summarizing some of the challenges of working across multiple scales, units and objectives. We will then discuss the development, ongoing tuning and validation of the fish module FEAST, highlighting transitions from original to current formulations of bioenergetics, movement and reproduction through several rounds of meetings with field biologists. Finally, we’ll detail what processes in the model are expected to respond to climate change, where we expect them to be buffered, and where they are non-sensitive. FEAST runs on a grid of ~10 km resolution and models size-based, two way interactions between 13 fish species (walleye pollock, Pacific cod, arrowtooth flounder, salmon, capelin, herring, eulachon, sandlance, myctophids, squids, shrimp, crabs and other), and the 7 zooplankton groups in the NPZ model (small/large microzooplankton, small/large copepods, euphausiids, jellyfish, and benthic infauna). Both temperature and advection from ROMS are used in the bioenergetics and movement components. The operating hypothesis in FEAST is that forage fish and macrozooplankton are tightly coupled in a two-way interaction, and the dynamics of this interaction under different climate scenarios is a strong structuring element for the ecosystem as a whole.