Temperature, size, and harvest method drive recovery in an Indigenous kelp fishery

Identifying how to harvest populations in a way that maintains ecological resilience is a fundamental issue in applied ecology. Fortunately, resources users around the world have gathered knowledge of these strategies over millennia. Today, within the context of new market opportunities and changing environmental conditions, communities are being faced with the conservation and management challenge of adapting traditional harvest systems within shifting social-ecological conditions. Egregia menziesii, an ecologically and culturally important intertidal kelp, has been harvested on the coast of British Columbia by the Haíɫzaqv (Heiltsuk) First Nation for generations. In light of an emerging commercial opportunity for a small-scale harvest, we worked in collaboration with Heiltsuk managers to examine effects of a traditional Egregia harvest. Using Indigenous knowledge interviews and a harvest experiment, we found no detectable effect of harvest treatment (25% frond removal) on Egregia recovery, and that pre-harvest size, site-level seawater temperature and wave exposure were the most important drivers of kelp recovery from harvest. Additionally, we found parallel understandings of these drivers within Heiltsuk Indigenous knowledge. Overall, we found that traditional Egregia harvest practices reflect the ecological conditions that confer resilience, and specifically that harvest practices rooted in Indigenous knowledge promote recovery. Lastly, we provide an example of how successful co-produced research can produce locally legitimate and relevant research outcomes to inform resource management problems in a changing world.