Mayumi Arimitsu

Mayumi (“Yumi”) Arimitsu (BA, MSc, PhD) is a Juneau-based fish ecologist whose research focuses on the energetic “bottleneck” of North Pacific food-webs: the forage fish and zooplankton that sustain seabirds, marine mammals, and commercially important fishes. Dr. Arimitsu spent more than two decades with the U.S. Geological Survey’s Alaska Science Center, developing her food-web expertise in glacial-marine ecosystems, and progressing to pelagic food-webs on the continental shelf and Aleutian Islands. During this  period she served as USGS Seabird and Forage Fish Program Leader and was invited to lead the multi-agency pelagic ecosystems food web coordinator for Gulf Watch Alaska, overseeing long-term, interdisciplinary studies that linked seabird and marine mammal foraging success to ocean conditions and prey fields. Her seabird research is especially notable for “predator-based sampling”—using seabirds as precise, repeatable collectors of forage fish information through time. One flagship synthesis used decades of diet records from multiple colonies to track climate–prey relationships for horned and tufted puffins and rhinoceros auklets across the North Pacific. At Middleton Island in the Gulf of Alaska, she collaborated with the Institute for Seabird Research and Conservation to help maintain and publish detailed diet datasets for rhinoceros auklets and tufted puffins (among other species), work that supports both seabird ecology and fisheries-relevant indicators (for example, prey size/condition and recruitment signals). More recently, her collaborations have illuminated how extreme marine heatwaves can synchronize crashes in key forage fish portfolios—disrupting energy flow to top predators and reshaping food webs at basin scales. Currently, she is a marine research scientist at Ocean Bight LLC, and focuses on applied, quantitative ecosystem science in Alaska.  She has recently been recognized with a Climate Science Bridge Fellowship (2026), extending her leadership from long-term monitoring to science translation and communication.