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Illegally anchored boats are ruining Richardson Bay

But they may have nowhere else to go

Boats parked at the marina in Richardson Bay, with kayaks on the beach in the foreground.
These boats are anchored legally at the pier, but illegal “anchor outs” in the middle of the bay are an environmental hazard.

[Update: Beth A. Pollard, executive director of the Richardson’s Bay Regional Agency told Curbed SF that the agency “shares the concern about maintaining the vitality of eelgrass in Richardson’s Bay” and that “[we;ve] hired a prominent environmental firm, to advise us about the safest places to moor in the bay to preserve eelgrass” and “identify the best mooring equipment and techniques” to protect bay ecology.]

We are working collaboratively with a number of stakeholders – including Audubon California and the Richardson Bay Special Anchorage Association – to reduce vessel impacts on eelgrass.

According to research conducted by Audobon California, the number of boats parked illegally in Sausalito’s Richardson Bay threatens to sink the local ecosystem and invite environmental disaster in the North Bay.

In a paper published in the peer-reviewed journal Environmental Management, Julia J. Kelly et al say that too much boat traffic in the bay has wreaked havoc on the local eelgrass population.

A sprawling network of creatures in the area rely on the grasses to survive, and boat anchors are quite literally punching holes in their populations.

“Using aerial imagery and GIS analyses, we determined the amount of direct damage to eelgrass caused by anchor outs,” the researchers write in Environmental Management. According to the analyses, as much as 41 percent of the bay’s eelgrass beds—84 acres—are damaged by “anchor out” boats that, more often than not, are illegally anchored there.

Among the conclusions:

  • Seriously, eelgrass is way more important than you think: “[Seagrasses] are a foundation species for ecosystem services including food for marine herbivores; nursery sites for commercially and ecologically important fish and invertebrate species; high diversity of fish, epifauna, and bird species; nutrient cycling; sediment stabilization; and protection of shoreline infrastructure through wave-action reduction.”
  • It’s a staple of the bay’s food supply: “Grazers such as amphipods, snails, dabbling ducks, and geese obtain food from eelgrass beds directly through consumption of eelgrass blades. Other consumers obtain food indirectly by eating invertebrates and diatoms living in the eelgrass. Tens of thousands of migratory birds take fish and associated epifauna from eelgrass beds in Richardson Bay.”
  • Illegal boat anchoring is quite common in the bay: “[The Richardson Bay Regional Agency] stipulated that boats may not anchor for longer than 72 hours; however, many boats anchored in the beds are present throughout the year and serve as homes, known locally as anchor-outs. The number of anchor-outs increased from an average of 90 boats in the early 2000s to a high of 240 boats in 2016.”
  • Ousting unauthorized boats is sensitive because many marines have nowhere else to go: Although situated in one of the wealthiest counties in California, the Richardson Bay anchor-out demographic includes artists, anglers, disabled individuals, and many who are unable to afford Bay Area rental prices.”
  • But letting them stay wreaks havoc on the bay’s ecosystem: “We identified areas of the eelgrass beds that were damaged by anchored vessels through manual interpretation of photographs. [...] 25 percent of the eelgrass bed was apparently damaged by anchor-outs The high damage estimate indicated [...] 41 percent was damaged by anchor-outs.”

Again, despite the potential for cynical reactions to the news, eelgrass really are a critical resource.

The National Oceanic and Atmospheric Association says that “eelgrass forms the base of a highly productive marine food web” that “produces food and oxygen, improves water quality by filtering polluted runoff, absorbs excess nutrients, stores greenhouse gases like carbon dioxide, and protects the shoreline from erosion.”

According to the Richardson Bay Audubon Center, “There is concern that the long-term decline in bird numbers and herring in Richardson Bay and other parts of San Francisco Bay is linked to the decline in native eelgrass beds.”