California Eelgrass Mitigation Policy Overview

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Eelgrass habitat is one of the most valuable and productive habitats in the marine environment. It provides many important ecosystem functions: foraging areas and shelter to young fish and invertebrates, food for migratory waterfowl and sea turtles, and spawning surfaces for species such as the Pacific herring. Not only does eelgrass form the base of a highly productive marine food web, but it is also unique in producing food and oxygen, improving water quality by filtering polluted runoff, absorbing excess nutrients, and storing greenhouse gasses such as carbon dioxide. By trapping sediment, stabilizing the ocean floor, and minimizing the force of wave energy, eelgrass beds also reduce coastal erosion. Eelgrass is found along the coast, and in bay and estuarine environments in California.

Because of its critical contribution to a functioning and thriving ecosystem, eelgrass habitat is a high-priority area for conservation, management, and research. NOAA Fisheries has identified eelgrass as a Habitat Area of Particular Concern (HAPC) for species managed under the Pacific Salmon and Pacific Groundfish Fishery Management Plans.

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Working Towards No Net Loss of Eelgrass

NOAA Fisheries published the California Eelgrass Mitigation Policy and Implementing Guidelines (CEMP) in October 2014. This policy states our goal of no net loss of eelgrass habitat function in California and provides guidance for conducting surveys, impact assessment, and compensatory mitigation. Eelgrass surveys are recommended by staff when a project may impact eelgrass. If impacts occur, a compensatory mitigation project may be initiated, and monitoring reports are submitted to document the mitigation project progress.

NOAA Fisheries 2014-2021 Survey Review Summary

NOAA Fisheries conducted a review of survey and monitoring reports submitted by project applicants between 2014 and 2021. We reviewed 120 survey and monitoring reports. Fourteen compensatory mitigation projects were initiated during this time, one additional compensatory project was planned, and four others were anticipated. The majority (93%) of these projects occurred in Southern California. The eelgrass surveys were conducted by a variety of different environmental consultants to determine the effects of coastal development projects on eelgrass habitat.

Survey Compliance

Very few surveys (1.7% of those reviewed) completely followed all the CEMP survey recommendations. Of the surveys reviewed, 53.7% were considered to be partially compliant, meaning they addressed the most critical survey parameters in a way that managers could make a reasonably well-informed decision regarding eelgrass impacts. Approximately 44.6% of the surveys didn’t follow the guidelines, making it difficult to meaningfully determine eelgrass impacts as described in CEMP. In particular, there was limited compliance in spatial distribution and percent cover survey parameters, and spatial data (e.g. geographic information system (GIS) files) was rarely provided.

Mitigation Actions & Milestones

The review found that coastal development projects impacted approximately 43.5 acres of eelgrass habitat, which triggered mitigation actions. Out of the 13 projects reviewed, five of these projects utilized the U.S. Navy’s San Diego Bay Eelgrass Mitigation Bank. Two projects, the Lower Santa Ana River Sand Management Project and the City of Newport Beach Regional General Permit 54 Maintenance Dredging Project utilized Comprehensive Management Plans for flood control, dock replacement, and maintenance dredging. The Sunset/Huntington Harbour Maintenance Dredging Project was the only in-kind compensatory mitigation project to have gone through the typical 5-year performance monitoring period, and it did not fully achieve the performance standards.

Overall, approximately 77% of the compensatory mitigation projects were meeting their milestones.

Although we were unable to quantify the area conserved during the review process, we believe the CEMP has contributed to the protection of more eelgrass habitat area than the observed impacts (~ 43.5 acres). Mitigation performance has been mixed, but any current mitigation shortfalls appear to be less than 1 acre.

View Table 1. Summary of Mitigation Projects for more information. The table includes the year, type of mitigation, region of California, approximate location, impact area in square meters, and if the most recent milestones were met during the 2021 CEMP review.

Recommendations

The CEMP has effectively provided NOAA Fisheries staff with a consistent basis for providing recommendations for the conservation of eelgrass resources in California. Several of our agency partners have adopted the CEMP as part of their permitting process and consider the recommendations as a uniform strategy for conservation.

While the current consultation database and tracking system is not able to quantify the total area of protected eelgrass habitat, NOAA Fisheries believes implementing the CEMP has effectively avoided and/or minimized more impacts to eelgrass habitat areas than observed impacts. However, the uncertainty associated with reporting and survey compliance suggests the potential for additional impacts that are not being explicitly and/or accurately accounted for.

As with any policy, correct implementation and commensurate compliance are key to realizing the maximum benefits that the policy could provide. External community collaborators have recommended that we update the CEMP to strengthen its protections and address multiple ecological services beyond habitat provision for fishery species. NOAA Fisheries proposes to focus on the following recommendations to improve implementation:

1. Develop an internal tracking system for eelgrass surveys and mitigation monitoring reports to help capture more data, streamline quality assurance, and provide more efficient feedback on compliance.
2. Collaborate with partner agencies to develop permit language consistent with the CEMP guidelines.
3. Develop additional guidance to improve reporting compliance (e.g., eelgrass habitat characterization and survey approach, mitigation ratios, mitigation ratio calculator assumptions, etc.).
4. Maintain the CEMP goal and evaluate future refinement through technical assistance and interagency coordination for improved implementation.

For more information, contact Sara Azat and/or Bryant Chesney.