Abstract
Kelp is an ecologically, economically, and culturally important species that is facing global declines. This pilot project investigated if declines in Bull Kelp in the Saturna Island Interim Sanctuary Zone could be attributed to increased herbivory by sea urchins, and/or thermal stress caused by increased ocean temperatures. In areas where sea urchins were excluded, bull kelp was more abundant and in areas where sea urchins were not excluded, heavy grazing was observed. Throughout the summer 2023 study period, sea surface temperature did not exceed bull kelp's adult or gametophyte thermal tolerance. Restoration of this site should include methods to reduce sea urchin herbivory, while carefully considering cultural and ecological implications.