March 15, 2017 - For nearly 20 years, Channel Islands National Park biologists recorded the same number of black abalone (Haliotis cracherodii) at Cuyler Harbor: zero. Modern abalone monitoring began at Cuyler Harbor, located on San Miguel Island, in 1992. At that time, biologists counted 165 of the dark, smooth-shelled sea snails. After 1997, they found none. The black abalone had fallen victim to withering syndrome, a disease that may have been exacerbated by the warm-water El Niño events of the 1990s. Black abalone throughout the region suffered a similar fate. By 1998 less than one percent of southern California's historic black abalone population remained.
Fortunately, at Otter Harbor, just a few miles away on San Miguel Island, a depleted population of survivors persisted. In parts of the rocky intertidal zone that were once covered in layers of abalone five individuals deep, fewer than a hundred individuals remained. Small remnant populations hung on in other places as well, but mostly at sites on San Miguel. The survivors were typically older, larger abalone, and for several years, that was almost all biologists could find. There was little evidence of a successful younger generation, which didn’t bode well for the future.