Bottom trawling is a widespread source of seafloor disturbance inside the exclusive economic zones of coastal nations

This $233,305 Cooperative Agreement award from the National Oceanic and Atmospheric Administration (NOAA) under the Sea Grant Support program (CFDA 11.417) will fund research at Oregon State University (OSU) to evaluate the ecosystem impacts of bottom trawling in the California Current Ecosystem.

The key objectives are to refine the California Current Atlantis Model (CCAM) by developing a detailed benthic sub-model that parameterizes the physical impacts of bottom trawling on benthic processes. OSU will build this benthic biogeochemical sub-model using C++ and data from a recently reopened trawl rockfish conservation area. The sub-model will be integrated into CCAM to assess the sensitivity of the broader ecosystem to benthic processes and changes in bottom trawling levels, including the impacts of reopening trawl areas off the Oregon coast. This research is expected to provide critical insights to inform management decisions regarding bottom trawling in the California Current Ecosystem.

However, few research studies of trawling impacts have assessed whole-ecosystem effects or have examined impacts on multiple spatial and temporal scales. The proposed project will focus on population and ecosystem dynamics. More specifically, I will evaluate how bottom trawling impacts local and regional ecosystem processes in the california current ecosystem by refining the end-to-end ecosystem model known as the california current atlantis model (CCAM) through the addition of a detailed benthic sub-model that parameterizes the direct physical impacts of bottom trawling on benthic processes. To accomplish this, I will build a benthic biogeochemical model that will serve as the sub-model using the C++ coding language. The sub-model will be parameterized using previously collected samples and associated data from a recently reopened trawl rockfish conservation area (RCA). This dataset will also be used to test, fine tune, and ground truth the benthic sub-model before IT is integrated with CCAM. Using video footage showing trawled sediment from surveys in the recently reopened trawl RCA, I will use photogrammetry to estimate the depth penetration and physical impacts of region-specific bottom trawling along with radiotracer data. I will then run simulations using CCAM with the new benthic sub-model and compare outputs with prior simulations to assess the sensitivity of CCAM to the benthic sub-model and the importance of benthic processes to the local and broader regional ecosystem. After this initial assessment, I will run simulations that include bottom trawling to assess how changes in bottom trawling may impact local and regional ecosystems using different management scenarios, including the effects of reopening of the trawl RCA off the oregon coast, coast-wide reopening of the trawl RCA on the california current ecosystem, and, using historical data from records and log books, assess how increased bottom trawling prior to the establishment of the trawl RCA may have altered the ecosystems at different spatial scales.