Marine heatwaves (MHWs) are increasing globally, causing significant disruptions to marine ecosystems. This study examines the effects of MHWs on the structure and function of the Northern California Current ecosystem. Using data from 361 taxa grouped into 86 functional groups, along with diet information and previous modeling efforts, two food web networks were constructed: one before and one after the onset of MHWs. The results show that MHWs have led to significant changes in ecosystem structure and function, particularly in gelatinous taxa, with a notable increase in pyrosomes. These changes have altered trophic relationships and energy flux, potentially having profound consequences for ecosystem structure and function. The study highlights the need for further research to understand the long-term impacts of MHWs on marine ecosystems and to develop strategies for climate-resilient fisheries. The findings suggest that MHWs may lead to shifts in species distribution and abundance, affecting commercially important fish species and the overall health of marine ecosystems. The study also emphasizes the importance of ecosystem modeling in predicting future changes and managing fisheries in the face of climate change.Marine heatwaves (MHWs) are increasing globally, causing significant disruptions to marine ecosystems. This study examines the effects of MHWs on the structure and function of the Northern California Current ecosystem. Using data from 361 taxa grouped into 86 functional groups, along with diet information and previous modeling efforts, two food web networks were constructed: one before and one after the onset of MHWs. The results show that MHWs have led to significant changes in ecosystem structure and function, particularly in gelatinous taxa, with a notable increase in pyrosomes. These changes have altered trophic relationships and energy flux, potentially having profound consequences for ecosystem structure and function. The study highlights the need for further research to understand the long-term impacts of MHWs on marine ecosystems and to develop strategies for climate-resilient fisheries. The findings suggest that MHWs may lead to shifts in species distribution and abundance, affecting commercially important fish species and the overall health of marine ecosystems. The study also emphasizes the importance of ecosystem modeling in predicting future changes and managing fisheries in the face of climate change.