Hawaiian Monk Seal (Neomonachus schauinslandi) Marine Debris Entanglement Risk Varies With Size Class and Sex Marine Mammal Science

Plastic pollution is a recognized threat to global oceans (National Academies of Sciences, Engineering, and Medicine 2022; United Nations Environment Programme 2021; United Nations Environment Programme 2023). Hawaiian monk seals (Neomonachus schauinslandi), listed as endangered under the US Endangered Species Act and currently numbering approximately 1600 individuals (Carretta et al. 2024), have been the subject of long-term demographic study and conservation action. Since the early 1980s, when regular monitoring of the species began, entanglement of monk seals in marine debris has been recognized as a serious threat, and efforts to disentangle seals and remove debris from their habitat have been major conservation activities (Donohue et al. 2001; Henderson 2001). Baker et al. (2024) showed that large-scale marine debris removal efforts have effectively reduced this threat to monk seals in some locations.