Eelgrass Restoration Off Santa Barbara

In addition to underwater reforestation, a pilot project in meadow restoration is currently enjoying great success in the waters of southern California. The place is Frenchy’s Cove, the easternmost end of West Anacapa Island, one of the Channel Islands, where until the early 1990s thick eelgrass beds thrived at depths of 15 to 30 feet. The threats to eelgrass include pollution, anchor use, storms, and sediment movement. The Anacapa beds, however, fell victim to another menace: white sea urchins, which established themselves during the 1982–84 El Niño. Although these urchins typically live at greater depth and at very low densities, the influx of warm water spurred a population boom, creating densities as high as 63 urchins per square meter. And they were hungry, so they went where the food was: upslope, into the eelgrass beds. By 1991, all eelgrass (as well as kelp) in Frenchy’s Cove was gone. The urchins then died off from starvation and disease, and although the kelp forest is beginning to reestablish itself at Frenchy’s, not a blade of eelgrass returned.

• PRINT THIS ARTICLE

• EMAIL A LINK TO THIS ARTICLE

• TELL US WHAT
YOU THINK

This was a job for Santa Barbara ChannelKeeper. Working with the Channel Islands Research Program and NOAA Fisheries’ Community-based Restoration Program, ChannelKeeper launched an 18-month pilot program in 2001 to resurvey Frenchy’s Cove, determine where to harvest plants and seeds for replanting, collect and culture seeds in portable aquaria as junior high classroom projects, and plant eelgrass at two different depths and at two different densities. In June and July 2002, divers moved several hundred plants from a healthy eelgrass bed off Santa Cruz Island to the devastated Anacapa bed, at two depths. Brittle stars proved a problem lower down, where they climbed the young transplants, weighting them and making them more accessible to grazers. At shallower depths, in contrast, the eelgrass thrived and was even self-propagating by spring 2003. (The plants reseed, but spreading also occurs by means of rhizomes, tough roots that sprout genetically identical plantlets as they extend beneath the sand.) As of October 2003, there were more shoots than had been transplanted the preceding year.

When I visited the ChannelKeeper offices in March, head biologist Jessie Altstatt didn’t even try to contain her delight as she showed me videos of the flourishing eelgrass bed at 20 feet. ChannelKeeper had recently organized a census with the help of volunteer divers and hundreds of plastic spoons. Wherever there was an eelgrass plant, they stuck a spoon in the sand. When the entire patch had been surveyed, the spoons were collected and counted (a low-tech but pretty accurate approach). The results buoyed everyone’s spirits: the bed was dense and healthy, with new plants sprouting and no sign of stress. The eelgrass bed of Anacapa—and with it many of the 150 or so animal species that rely on these beds for food and refuge, including pipefish, sarcastic fringehead, kelpfish, and miniature snails that clean the grass blades of encrusting bryozoans—is making a comeback.

—Anne Canright

To return to the Eelgrass story, click here.