Assessment of practical methods for re-establishment of northern California bull kelp populations at an ecologically relevant scale

Project Number
R/HCEOPC-13
Project Date Range
-
Funding Agency
National Oceanic and Atmospheric Administration (NOAA)
Focus Area(s)
Healthy Coastal Ecosystems

 

Sea urchin overgrowth is one factor inhibiting the recovery of kelp forests off the coasts of northern and central California. Bull kelp populations north of San Francisco Bay have been particularly hard hit, with little to no observable recovery outside of a few areas. Any efforts to restore the bull kelp (Nereocystis luetkeana) in these areas requires both a reestablishment of the kelp itself, as well as an end to the sea urchin overgrazing.

This study aims to support the development of cost-efficient methods for re-establishing northern California bull kelp populations at ecologically relevant spatial scales following sea urchin removals. The researchers plan to test various culture methods for growing bull kelp for restoration purposes; conduct controlled field experiments to determine the most successful method for outplanting bull kelp recruits to areas following sea urchin removal; and then monitor the bull kelp outplant growth, survival, and reproduction at field sites.

The researchers are working in partnership with governmental and non-governmental partners that are currently working on urchin removal, and Monterey Bay Seaweeds, a for-profit seaweed farm. The results of the project will directly inform efforts to restore kelp once urchins are removed.

 

Several “bonsai” bull kelp grown at Monterey Bay Seaweeds for bull kelp restoration. Photo credit: Bennett Bugbee
Several “bonsai” bull kelp grown at Monterey Bay Seaweeds for bull kelp restoration. Photo credit: Bennett Bugbee
Cultured bull kelp at various stages of development at Monterey Bay Seaweeds. The smallest blades are about 1 cm in length and the largest about 20 cm. Photo credit: Bennett Bugbee
Cultured bull kelp at various stages of development at Monterey Bay Seaweeds. The smallest blades are about 1 cm in length and the largest about 20 cm. Photo credit: Bennett Bugbee
“Green gravel” inoculated with microscopic bull kelp for restoration. Photo credit: Bennett Bugbee
“Green gravel” inoculated with microscopic bull kelp for restoration. Photo credit: Bennett Bugbee
Baby cultured bull kelp at 3–4 weeks old (100x magnification). Photo credit: Bennett Bugbee
Baby cultured bull kelp at 3–4 weeks old (100x magnification). Photo credit: Bennett Bugbee
A cultured “bonsai” kelp individual with reproductive structures visible as darker patches in the blades. Photo credit: Andrew Kim
A cultured “bonsai” kelp individual with reproductive structures visible as darker patches in the blades. Photo credit: Andrew Kim

 

Principal Investigators
Michael Graham
Moss Landing Marine Laboratories / San Jose State University
Co-principal Investigators
Scott Hamilton
Moss Landing Marine Laboratories / San Jose State University