Researchers say vital marine plant is improving

By KRISSY WAITE | kwaite@marinij.com

PUBLISHED: November 28, 2023 at 6:22 p.m. | UPDATED: November 28, 2023 at 6:27 p.m.

Eelgrass health in Richardson Bay might be taking a turn toward recovery — news that was met with cautious optimism this month by the bay’s managers.

The most recent findings on the health of the eelgrass were presented to the Richardson’s Bay Regional Agency board at a special meeting on Nov. 16.

Overall, researchers found that damage to the eelgrass bed has plateaued, said Rebecca Schwartz Lesberg, president and founder of Coastal Policy Solutions, the agency’s consultant.

The health of the eelgrass, an assessment that includes all threats to it, remains questionable, but the acreage is no longer decreasing, according to Schwartz Lesberg. While it is also not growing, she said this is a sign that restoration and conservation efforts are working.

“That’s very reassuring,” Schwartz Lesberg said. “Now is the time to really focus on healing and repairing the damage that’s been done.”

Decades of vessels anchoring, often illegally, amid the eelgrass have resulted in extreme damage. Efforts in recent years from environmental groups and the bay agency — at the behest of the state — have reduced the boats anchored on the bay from more than 200 in 2016 to around 50, giving the powerhouse plant a chance to recover.

Eelgrass beds reduce coastal erosion and ocean acidification, sequester carbon and provide habitat for commercially, recreationally and ecologically important marine life, according to experts.

The bay agency enforces a 72-hour anchoring limit and plans to remove all vessels from the eelgrass protection zone, a designated area for environmental conservation, by October 2024. A settlement with the San Francisco Bay Conservation and Development Commission requires that all illegally anchored vessels be removed by Oct. 15, 2026.Brad Gross, executive director of the Richardson Bay agency, said the report is evidence that the approach is working.

“Eelgrass is the foundation of a healthy, thriving Richardson Bay,” Gross said. “The latest report shows clear signs that our efforts to relocate vessels off the protected areas of the anchorage are having lasting positive impacts.

“By taking a compassionate approach to relocating these vessels and being deliberate in our decisions, we are protecting and restoring our environment in a way that allows everyone to enjoy Richardson Bay,” he said.

Jack Ryan, vice chair of the agency’s board, praised the presentation but asked whether the data set could be more robust. The sonar images and surveys used only went back a few years. The consultant began working on the issue around 2020, according to Schwartz Lesberg.

“I thought the picture it portrayed was very optimistic,” said Ryan, who is the mayor of Tiburon. “It will be interesting going forward to see how it plays out, especially with climate change and other stressors, but it’s better to have an optimistic picture than not.”

Belvedere Mayor Jim Lynch, chair of the agency board, asked if the study compared the Richardson Bay eelgrass bed with other beds in the area. Schwartz Lesberg said no, but agreed it would be a good idea in the future. She noted that the bed is the second largest in San Francisco Bay — the largest is off of Pinole — with only about five other beds in estuaries off the state’s coast.

Supervisor Stephanie Moulton-Peters, also a member of the agency’s board, inquired about eelgrass within the Richardson Bay Audubon sanctuary, which lies to the north of the zone. Schwartz Lesberg said that while there is eelgrass in the area, it is less dense. She credited this to shallower and warmer waters, which stresses the eelgrass.

Other stressors — such as warming waters, eelgrass wasting disease and competition from algae — will continue to worsen over the next few years because of climate change, according to Schwartz Lesberg.

However, the damage patterns caused by these factors look different than damage attributed to the anchor-out community. Keeping the stress of vessels low will give the eelgrass the best odds at surviving climate change-related threats, the consultant said.

“Anchoring and eelgrass are simply mutually exclusive activities and we cannot become complacent about efforts to protect the eelgrass bed just because we’ve seen this plateau in damage,” Schwartz Lesberg said. “This plateau is telling us that what we are doing is working. We need to keep doing it and we need to actively restore eelgrass.”

Robbie Powelson, an advocate for the anchor-out community, said he was not convinced by the data in the presentation. He said if the agency was truly concerned with the environment, it would also be looking at sewage runoff and dredging.

“They only care about removing a group of people who they’ve deemed are undesirable,” said Powelson, who lives in Marin. “They are just blaming a community that’s been there for over a hundred years.”

He said considering how many boats have been removed by the agency in recent years, he would expect a much larger increase in eelgrass acreage, not a plateau.

“The number of boats has dropped a ton, but you don’t see the same level of improvement in eelgrass,” Powelson said. “They’re not even seeing an increase, even though they’ve crushed over a 100 boats now. You’d expect something substantial if anchor-outs were truly the main culprit.”