It only has about one acre of the stuff — compared to the roughly 12,000-15,000 acres found in California statewide — but Crescent City Harbor’s efforts to transplant eelgrass following the March 2011 tsunami “is something the district should be proud of,” consultants say.

The Crescent City Harbor District is the first entity in Northern California to successfully undergo an eelgrass mitigation project under a new policy adopted in California in 2014, said Whelan Gilkerson, senior biologist with Arcata-based Merkel & Associates Inc.

Dubbing the project a test pilot for the new California Eelgrass Mitigation Policy, Gilkerson said while most efforts to transplant eelgrass have been largely unsuccessful in other parts of the North Coast, the eelgrass at the Crescent City Harbor is thriving.

“Most projects have failed or have not been tracked very well,” Gilkerson said. “And so, the district in a really good faith effort, while the policy is still in draft format, followed the guidelines. The idea was to see if we follow the new policy are we likely to generate better success with eelgrass mitigation, and they absolutely did.”

Found from Baja, California to Alaska, eelgrass provides a place for herring to spawn, Gilkerson said. It serves as nursery habitat for Dungeness crab and a place of refuge for baby rockfish trying to avoid predators, he said.

According to Deputy Harbormaster Lane Tavasci, the herring run that occurs in roughly March and April draws a lot of anglers to the harbor.

But, though its range is broad, eelgrass requires clean protected waters, so there’s “not necessarily large amounts of it,” Gilkerson said. Eelgrass is imperiled by water pollution and development, he said.

Despite the state’s size, Gilkerson estimated that there are only 12,000 to 15,000 acres of eelgrass in California.

Due to impacts from dredging, rock slope protection and dock replacement work following the March 2011 tsunami, the Crescent City Harbor was required to transplant an eelgrass bed near its public boat launch, Gilkerson said.

The harbor contracted Pacific Watershed Associates to transplant the eelgrass in 2013, according to the Year 5 Post-Mitigation Eelgrass Monitoring Report, which Gilkerson prepared in June 2018. Pacific Watershed Associates retained Merkel & Associates in 2016 to assist with monitoring the project. According to Gilkerson, the project was monitored for five years to ensure that transplant efforts were successful.

Though the new California Eelgrass Mitigation Policy required high planting ratios, the harbor surpassed that requirement by a huge factor, according to Gilkerson.

“We harvested the bed next to the boat launch right before dredging began,” he said. “One of the cool things about the project, the bed we completely harvested, it’s coming back in the same location. And above and beyond that, the mitigation (area) has grown like gangbusters. The harbor has more eelgrass than it’s probably ever had before.”

According to Gilkerson, the report he prepared in May 2018 was the last monitoring report needed for the Crescent City Harbor eelgrass mitigation project.

“It’s a nice thing for the district to have under their belt, to be the first ones to go through a new policy,” he said. “It’s the first project north of San Francisco Bay to be conducted and to follow through with a full five years of monitoring.”

Reach Jessica Cejnar at jcejnar@triplicate.com .

21436772