Abalones at risk: A global Red List assessment of Haliotis in a changing climate

RESEARCH ARTICLE Abalones at risk: A global Red List assessment of Haliotis in a changing climate Howard PetersID1*, Gina M. Ralph2¤, Laura Rogers-Bennett3 1 Department of Environment and Geography, University of York, Heslington, York, United Kingdom, 2 IUCN Marine Biodiversity Unit, Department of Biological Sciences, Old Dominion University, Norfolk, Virginia, United States of America, 3 Bodega Marine Laboratory, California Department of Fish and Wildlife and University of California Davis, Bodega Bay, California, United States of America ¤ Current address: Virginia Institute of Marine Science, William & Mary, Gloucester Point, Virginia, United States of America * howard.peters@york.ac.uk Abstract There is increasing awareness that marine invertebrates such as abalones are at risk from the combined stressors of fishing and climate change. Abalones are an important marine fishery resource and of cultural importance to Indigenous and non-Indigenous people. A highly priced marine delicacy, they are inherently vulnerable: individuals are slow-growing and long-lived and successful reproduction requires dense assemblages. However, their global conservation status is poorly understood. Using IUCN Red List methodology, we assessed the extinction risk to all 54 species of abalone (genus Haliotis). Of the 21 fished commercially for human consumption either now and/or in the past, 15 (71.43%) are classi- fied as threatened, i.e., those identified as Critically Endangered, Endangered or Vulnera-

ble. Of the 33 unexploited species, only five (15.15%) are so classified, making exploited species over four times more likely to face extinction, underscoring the impact of fishing on abalones already confronting a changing climate. The highest concentration of threatened species occurs along the North American Pacific coast. Here six of the seven species have been exploited, yet despite years of fishery closures with exemptions only in Alaska and Mexico, all are categorised as threatened. Climate driven stressors have led to mass mortal- ities, with competition from sea urchins and disease, aggravated by harmful algal blooms. In Australia the picture is mixed despite robust stock management, with some regions experiencing mass mortalities from marine heatwaves and viral spread. Poaching has reached its apogee in South Africa, where organised criminal gangs have reduced the legal fishery of Haliotis midae, ‘perlemoen’ almost to a footnote, accompanied by widespread recruitment failure. In response, the authorities have focused on abalone ranching and stock enhancement. In Japan, with a long history of abalone fishing, wild stocks are routinely supplemented with hatchery-bred juveniles. Collaboration between restoration aquaculture and fisheries, including sea urchin control and kelp restoration, offers hope for rebuilding stocks against a backdrop of escalating environmental stressors. PLOS ONE PLOS ONE | https://doi.org/10.1371/journal.pone.0309384 December 23, 2024 1 / 25 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS

Citation: Peters H, Ralph GM, Rogers-Bennett L (2024) Abalones at risk: A global Red List assessment of Haliotis in a changing climate. PLoS ONE 19(12): e0309384. https://doi.org/10.1371/ journal.pone.0309384 Editor: Carrie A. Holt, Fisheries and Oceans Canada, CANADA Received: August 31, 2023 Accepted: August 9, 2024 Published: December 23, 2024 Copyright: © 2024 Peters et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: The data underlying the results presented in the study are freely available from IUCN Red List of Threatened Species website on https://www.iucnredlist.org/ 1. Go to www.iucnredlist.org 2. Enter species’ taxonomic name, e.g. Haliotis iris 3. Click on species returned by system 4. Select download 5. Select appropriate option, e. assessment, range data, or map data Funding: The authors received no specific funding for this work.