Very high densities of urchins that graze through algal growth is the main challenge that prevents kelp forest growth in Greater Farallones National Marine Sanctuary. The primary strategy for kelp forest restoration is to remove urchins, or reduce their populations to give kelp space to grow. Credit: Steve Lonhart/NOAA

Bull kelp can grow 7–65 feet tall and grow up to a foot per day in ideal cool water conditions. Credit: Steve Lonhart/NOAA

In addition to providing habitat and food for numerous species and sequestering carbon, bull kelp forms underwater forests that historically supported coastal Indigenous communities, commercial and recreational fisheries, and local tourist economies. Credit: Keith Johnson

The goal of kelp restoration in Greater Farallones National Marine Sanctuary is a healthy, functional kelp forest ecosystem that is resilient to increased sea surface temperatures from marine heatwaves and intense weather patterns such as El Niño. Credit: Paul Chetirken

Permitted uncrewed aerial systems (drones) are used to map kelp canopy throughout Greater Farallones National Marine Sanctuary. These maps are crucial for identifying the extent of kelp growth annually. Credit: Abby Nickels

Commercial urchin divers will be part of the restoration by removing purple urchins at restoration sites that will be monitored. Credit: Grant Downey

Kelp restoration includes culturing kelp at UC Davis Bodega Marine Lab, where spores are cultivated to be used for outplanting in restoration locations in Greater Farallones National Marine Sanctuary. Credit: Jennifer Stock/NOAA