Monterey/Central California Coast

Giant kelp, the perennial, dominates to the south and bull kelp, the annual, to the north. The kelp bed in Carmel Bay, while ever changing, is most often an even mix of bull kelp and giant kelp.

A key feature of the kelp beds in Monterey, and south along the Big Sur Coast to Morro Bay, is the presence of the southern sea otter. With this urchin predator in the mix the marine events of 2013 to 2016 did not create quite the devastation here as farther north in Mendocino and Sonoma counties. But the die off of that alternate urchin predator—the sunflower sea star in 2013 with the onset of seastar wasting disease—combined with the warming ocean (the blob and ENSO 2014-2016) and the ensuing purple urchin population explosion did not leave the underwater area around Monterey unscathed. The past few years have left the kelp forest there intensely patchy: an area of dense kelp forest can be adjacent to an urchin barren, an area devoid of all but the spikey urchins. This mosaic of kelp beds is dynamic; kelp beds seem to come and go. A new bed of bull kelp just north of Point Pinos appeared in 2021, where none had been seen since 2013, and dense canopy reappeared in 2023 along the Cypress Coast to Pescadero, while the Tanker’s Reef giant kelp forest has been devastated by urchins and is the site of intense restoration efforts.

To the ecology of the Monterey Peninsula, the decades after the newly discovered, and protected sea otters were an enormous boon. Edna Fisher was their advocate. In 1938, within a month of their discovery, Edna Fisher, a UC Berkeley trained professor of zoology at San Francisco State College, was on the bluffs of Big Sur with binoculars observing and writing about sea otter behavior. Fisher published numerous papers from her observations and was the first biologist to describe the tool-using behavior of the sea otter, confirming what Indigenous observers had described. Her observations and papers describing the sea otter always surrounded by Nereocystis—the large “tubular kelp” clearly depicted as the otter’s nursery—confirm the intimate relationship of these two organisms, marine mammal and marine alga, an intimacy perhaps overshadowed by the dominance of Macrocystis in today’s kelp forests of Monterey. By keeping urchin and other herbivores in check, the sea otters that slowly reinhabited the near-shore waters around the Monterey Peninsula in the 1940s and 50s allowed kelp to reestablish and thrive. By 1957, 638 sea otters were counted between Cypress Point and Point Conception. Today there are 3,000.

Nereocystis’s intimate relationship with the southern, or California, sea otter (Enhydra lutris nereis) plays out, like so many ecological stories, in the supremely biodiverse waters surrounding the Monterey Peninsula. The tidepools here charmed Ed Ricketts who in turn charmed John Steinbeck. They created such seminal works as Between Pacific Tides and Cannery Row. The seaweeds here inspired the first comprehensive scientific flora of California seaweeds, titled Marine Algae of The Monterey Peninsula by Gilbert Smith published in 1944. Hopkins Marine Station of Stanford University is right next to the Monterey Bay Aquarium which is a neighbor to MBARI, their research arm. A remarkable amount of important marine science happens in these waters. 

The Monterey Peninsula has also been ground zero for countless commercial fishing enterprises, each collapsing “in the ashes of its own greed: first the sea otters (with the fur trade), then the whales, birds, abalone and sardines were exploited until they were largely gone.” (Palumbi and Sotka p. 5); its snug harbor supporting hundreds of vessels that have trolled and brawled with the ocean for everything from sardines to abalone to salmon and tuna. Monterey even had an active “kelpery” in the early 1930s, harvesting bull kelp to be pulverized and shipped to New York. There it was used to create dyes specifically for synthetic silks. 

The sheer abundance of this section of the ocean, especially in the first half of the twentieth century, seemed limitless in its ability to let us humans pull things out of it and sell them for profit. It was nearly limitless in its abundance…until it wasn’t. Until there was nothing left. Steve Palumbi, in his book The Death and Life of Monterey Bay, recounts this wholesale excavation of life from Monterey Bay. By 1944, he calls it “the dustbowl of the sea”—but then he recounts the remarkable recovery of the Bay with the marine richness we know today. This recovery started with the return of the southern sea otter, and some of the first marine protected areas in the country. The Monterey Bay Aquarium opened in 1984 with a mission to inspire conservation of the ocean. It brings countless visitors, year in and year out, to the edge of Monterey Bay to do just that.

“In 2017 this area was observed as an urchin barren, a carpet of purple urchins. With no more kelp in deeper water, the sea urchins moved towards shore to eat the red algae there. This dislocation of the urchins opened an opportune space for bull kelp to colonize and pioneer a new patch in the deeper waters the urchins had left. There was not any Macrocystis close by to shade the young Nereo, and enough red algae inshore as well as otters to keep the urchins from venturing back out again. While Nereocystis everywhere else along the California coast was getting eaten away, here was a new patch where bull kelp had not been seen in decades, exhibiting the opportunism that is a signature characteristic of bull kelp.”    

Observing and tabulating the specific behavior of sea otters as well as counting urchin and kelp stipes takes a tremendous amount of careful and methodical work, underwater, with scuba gear at that! The work of so many students and researchers in this heavily studied zone reminds us how much nuance and detail there is still to learn about ocean systems. Many of these studies highlight the dual ecological storylines that are often fought over in scientific circles: top-down versus bottom up forcing.