A Team Approach

Project Overview

In under a decade, 96% of bull kelp habitat has been lost along 350 km of coastline on the north coast of California. One of the most rapid and extensive losses of underwater forests to date was the result of an unprecedented combination of multiple stressors, including the loss of top predators (sea otters and sea stars) and an increase in frequency of warm water events. Across this region, kelp forest habitat largely transitioned to urchin barrens leaving a wake of ramifications including the continued peril of red abalone, multiple federal fishery disasters (e.g. salmon, red sea urchin) and loss of culture and identity for a community deeply rooted in the health of these invaluable underwater forests. 

Part of the 4% remaining kelp refugia on the North Coast was, for many years, at the mouth of the Big River estuary (Portuguese Beach) in Mendocino Bay, right off the Headland cliffs at the town of Mendocino. While this location withstood the great losses of kelp from 2014-2019, it began to show signs of deforestation in 2022. One year later, 91% of bull kelp refugia habitat was lost across the ~15 acre area within the cove. The decline of health in this iconic forest was detected by local divers, beachgoers, scientists, fishers and stewards who have a deep connection to this place and catalyzed a call to action. We know from the global community of practice that protecting a kelp forest before it disappears should always be the first priority when considering restoration interventions. In Summer 2023, the state of California launched the second round of the Accelerating Kelp Research Program (AKRP) funding, providing an interdisciplinary team led by The Nature Conservancy and the local community an opportunity to protect and expand this threatened kelp forest, using novel and innovative approaches. 

The Accelerating North Coast Kelp Recovery Interim Report describes our first year (Year 1, 2024) to recover a recently degraded bull kelp forest at Big River, Mendocino County under the AKRP (McHugh et al 2025). Here we report on our first year results of testing and deploying a strategic combination of kelp recovery solutions and providing community participation opportunities to build stewardship connections that exceeds the lifespan of this award. This project additionally includes a one-acre kelp restoration study at nearby Albion Cove led by the same Objective 1 project team (The Nature Conservancy, Moss Landing Marine Laboratories, Sonoma State University, Reef Check, California Sea Urchin Commission, and California Department of Fish and Wildlife) proposed as match to the funding award. 

This project has three objectives that each intentionally address ecological, economic and social considerations that are paramount to understanding the potential for scaled and accelerated kelp recovery. The approach is a multidimensional collaboration that builds on years of kelp restoration activities, while also incorporating the ideas, experiences and musings of those who live on and with the ocean. 

Objective 1 aims to recover five acres of degraded kelp forest habitat. Knowledge gained from grazer suppression and kelp enhancement activities will directly inform the scalability of kelp recovery, document the drivers of restoration success, and engage the local sea urchin fishery. This work will directly contribute to California’s Kelp Restoration and Management Plan (KRMP). Additionally, kelp restoration outcomes will support the 30 x 30 initiatives both domestically and globally through the Kelp Forest Challenge which aims to protect and restore 4 million ha of forest by 2040. Objective 2 addresses information gaps by developing predictive models to optimize restoration, quantify the effects of urchin harvest and impacts to the fishery, and provide guidance for climate readiness and the blue economy.  Furthermore, we aim to develop an understanding of urchin demographics at restoration sites, to eliminate any waste, and secure both food and non-food uses. Objective 3 will provide socio-economic value by creating a local trained workforce in restoration, an emerging and relevant field. The objective also seeks to engage the community and include broader perspectives through experience and art, ensuring California’s coastal communities are represented in coastal ecosystem recovery, policy, and management discussions. 

Implementation & Key Findings

(McHugh et al 2025) 

Objective 1 

• 15 commercial urchin divers spent > 600 hours underwater and strategically harvested 54,870 lbs (27.4 tons) of purple urchin from two locations: Albion (1 acre, 4 tons) and Big River ( 5 acre, 23 tons)
• For the first time in a kelp restoration scenario, a scalable pathway to market was developed with the California Department of Fish and Wildlife and allowed us to utilize and market urchin harvested for the project for food and non-food purposes 
• Grazer suppression at ‘kelp edges’ likely contributed to protected and expanded remnant refugia at Big River; there was a 172% increase in canopy coverage since Fall 2023 and emergent kelp became reproductive 
• We closed the life cycle of bull kelp in lab allowing us to reliably culture various life stages for kelp enhancement activities, year-round 
• Novel ARKEV (Array to Recover Kelp Ecosystem Vegetation) units at two field sites created invaluable young-of -the-year rockfish habitat. Within two months of outplanting, bull kelp on ARKEVs became reproductive and released trillions of spores 

Objective 2 

• Echino engineered marble stone has shown promise that an urchin-based marble engineered stone product could be supplied to architects and designers as a building material for the eco-friendly furniture and green building materials market in the construction industry 
• Prototypes have been advanced to demonstrate the marketability of urchin-derived biomaterials, specifically for the luxury design market. At the same time, Primitives Biodesign calculated the volume of urchin that could be absorbed by their product production, their target market capture, and the resulting impact on the urchin population 

Objective 3 

• Local opportunities were created to build local knowledge and bolster workforce development 
• KelpFest! reached over 1,500 people and elevated other ways of knowing kelp ecosystems. This work was shared in real time, with over 30 presentations and multiple media appearances reaching over 144,000 viewers, to accelerate the pace of learning and make work visible 
• 19 students were supported through this project via this program and matching infrastructure 
• The Mysterious World of Bull Kelp website (this website you are on!) was endorsed by the UN Decade of Change and continued to expand webstory content and reach to new audiences 

Please read the full Accelerating North Coast Kelp Recovery Interim Report HERE.