August 28, 2018

Commercial and Recreational Urchin Removal Efforts Tested along California’s North Coast In Hopes of Kelp Forest Restoration

By Tristin McHugh, Reef Check California North Coast Manager
As we have previously reported, California's North Coast has been hit by massive changes to its rocky reef ecosystem over the last five years that consequently led to the closure of the recreational red abalone fishery last year. Although oceanographic conditions have been more favorable along the North Coast this year and kelp is doing better in some places, we are still observing persistent urchin barrens.

Specifically, kelp densities at most of our sites are at or near zero, urchin densities continue to increase, and sunflower stars, an important urchin predator, continue to have low densities following the onset of the sea star wasting disease. Often these barrens persist for long time periods until some event such as a disease, large storm or a change in oceanic conditions leads to a die-off of the dense urchin populations.

Because of the rapid formation of urchin barrens, their pervasive presence in most North Coast sites, and the subsequent decline in abalone populations, scientists and stakeholders came together and formed the Kelp Ecosystem and Landscape Partnership for Research on Resilience (KELPRR) to take action in hopes that the kelp will have a chance to recover. KELPRR is currently enlisting the help of commercial urchin divers and recreational divers to remove purple urchins from reefs in the hope that kelp will return in the areas cleared of urchins. Commercial urchin divers have been consistently removing urchins from three targeted locations in the North Coast: Noyo Harbor, Caspar Cove, and Albion. Further, the California Department of Fish and Wildlife recently increased the limit for recreational take of purple sea urchins from 35 individuals to 20 gallons of urchins per diver per day. With this increased ability to harvest, recreational urchin removal efforts took place in Ocean Cove (early May) and Albion (mid-July).

Reef Check California’s involvement in the KELPRR partnership is to monitor the sites where our partners – commercial and recreational divers – are removing urchins before and following the removals. Reef Check is not involved in the removal of urchins in the North Coast. The data we collect will assist in the evaluation of these restorative efforts and their effectiveness in changing these reefs from urchin barrens back into kelp forests. Reef Check’s monitoring efforts will also identify any unintended consequences of these removals such as the appearance of invasive or unusual species should they occur in response to the urchin removals. This season, we have surveyed all five sites where commercial and recreational urchin removal efforts have been targeted, and plan to follow up with more surveys as these efforts continue.