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

Australasia. This sector includes endemic species only occurring in Australia and New Zealand together with their islands. There are 14 species (Table 6). To fish for abalones in Australian waters, the animal must be of a minimum size, and although some specimens of H. elegans (LC) and H. scalaris (LC) are large enough for human consumption, they fail to conform to these regulations and cannot be legally fished. Many spe- cies suffer from increasingly frequent MHWs, including H. brazieri (NT), a small, scarce spe- cies with a fragmented population [81], and H. melculus (VU), an extremely rare species that occurs along the Sunshine Coast of southern Queensland [82], an area zoned for shoreline development, including artificial reef construction. The resultant sediment transport is an ongoing threat to this species’ shallow water habitats throughout its range [83]. H. laevigata (VU), known as greenlip abalone, although subject of a well-managed commercial fishery, has seen a decline in biomass as a result historic fishing pressure, MHWs in the west of its range, together with poaching [84]. Of eight fishery zones across four jurisdictions, none is currently classified as sustainable [85]. H. roei (NT), is the smallest of the three commercially fished Aus- tralian abalone and is just 2% of the total take. The majority occurs in Western Australia where a MHW in 2011 decimated stocks inflicting 99% mortality in its most northerly, i.e., warmer reaches, the effects of which are still reflected in its overall abundance [86]. There is a robust

management plan for its recovery but the increasing incidence of MHWs point to a problem- atic future. H. rubra (VU) has two subspecies: H. rubra rubra, known as blacklip abalone and H. rubra conicopora known as brownlip abalone with the latter restricted to the southwest of Western Australia. Blacklip abalone comprises 80% of the total Australian abalone catch. Of 14 fishery zones across four states, eight are classified as sustainable, two are depleting, two are depleted and two are undefined through lack of data [87]. Although this is now a well-regu- lated and managed fishery, this species is also exposed to the effect of MHWs and has also been subject to viral infection. Abalone viral ganglioneuritis (AVG), introduced into the marine environment from an aquaculture facility located in Western Victoria, resulted in up to 90% mortality in down-current waters, and although the threat is now considered low, it is an ongoing concern [88]. H. rubiginosa (CR) (Fig 7) is endemic to Lord Howe Island in the Table 6. Abalone species of Australasia. Species Size C Distribution Cat mm Australasia H. brazieri 50 Mooloolaba, S. Queensland to Jervis Bay, NSW, poss. to Wilson’s Promontory, Vic. NT H. coccoradiata 80 S. of Brisbane, S. Queensland to Cape Conran, Victoria, poss. to SE of Melbourne LC H. cyclobates 97 Esperance, WA to Wilson’s Promontory, Victoria LC H. elegans 120 Esperance, north to the S. passage of Shark Bay, WA LC H. laevigata 230 C Geographe Bay S. of Perth, WA to Victoria/NSW border; N. coast of Tasmania VU

H. melculus 56 Keppel Island, Queensland to the border with NSW VU H. roei 139 C Port Fairy, Victoria to Shark Bay, WA NT H. rubiginosa 56 Lord Howe Island, NSW CR H. rubra 248 C NSW, Victoria, Tasmania, South Australia and SW Western Australia VU H. scalaris 125 Kalbarri, WA to Victoria-NSW border and Tasmania LC H. semiplicata 75 Esperance north to Geraldton, Western Australia LC H. australis 110 C New Zealand incl. Campbell Is, Stewart Is, Auckland Is and the Chatham Islands LC H. iris 198 C North and South Is, Stewart Is, Chatham Is, The Snares Is and Three Kings Is. LC H. virginea 75 All of New Zealand and outlying islands LC ‘C’ denotes commercially fished. https://doi.org/10.1371/journal.pone.0309384.t006 PLOS ONE Abalones at risk: A global Red List assessment of Haliotis PLOS ONE | https://doi.org/10.1371/journal.pone.0309384 December 23, 2024 15 / 25