The Northeast Pacific Ocean is experiencing its fourth-largest marine heat wave on record, referred to as NEP25A, which began in May 2025. This heat wave has expanded to cover approximately 8 million square kilometers, significantly impacting marine ecosystems. Experts attribute the increase in marine heat waves to climate change, with five of the six largest events occurring in the last six years. The previous heat wave from 2013 to 2016 caused severe ecological damage, including the collapse of kelp forests and mass deaths of marine wildlife. NEP25A has already led to sightings of warmer-water species in northern areas and signs of harmful algal blooms along the Oregon Coast. While NOAA forecasts suggest that conditions may ease near the West Coast as winter approaches, the long-term implications for marine life and fisheries remain concerning.