Climate Change Threatens the Survival and Recovery of Black Abalone

Black abalone are sensitive to climate change impacts, such as increasing water temperatures and increasing sedimentation events from intense fire and storm activity. These challenges make them more vulnerable to lethal disease and burial.

Black abalone, which are plant-eating marine snails, once thrived along the California and Baja coasts but are now endangered. They are one of seven abalone species that live along North America’s west coast, inhabiting rocky shores where they eat drifting fragments of kelp. Their proximity to land makes them particularly vulnerable to climate-related events that impact the intertidal ecosystem.

The species is historically significant to the Chumash people. Throughout history, they harvested black abalone for food, trade, jewelry, ceremonies, and more. European settlement increased the species’ popularity, leading to active commercial and recreational harvests and species declines. In the mid-1980s, withering syndrome devastated populations of black abalone throughout the southern part of their range. In response, the State of California prohibited harvest of black abalone in 1993. Today, harvest remains prohibited for this once-abundant and culturally significant resource.

The main threats to black abalone—withering syndrome and overfishing—led to the species’ listing under the Endangered Species Act in 2009. Ongoing and emerging threats include disease, illegal harvest, sedimentation, contaminant spills, and ocean acidification. Climate change impacts exacerbate threats to the species, further challenging their recovery.

Climate-Related Impacts

Increasing Water Temperatures

The black abalone’s primary threat is withering syndrome, which fatally attacks its digestive organs. This disease led to mass mortalities within the species. Increased water temperatures can accelerate the disease’s transmission and mortality rates for the species. The disease is likely present in all wild black abalone, which can carry the pathogen without manifesting symptoms. Disease-related die offs are most prevalent in the southern portion of the species’ range, where water temperatures are relatively warmer.

read more at fisheries.noaa.gov.