First record of microplastics found in shark mermaid’s purses: a hidden threat to ocean apex predators during embryonic stage

The pervasive presence of microplastics in marine ecosystems poses a significant threat to apex predators such as sharks, already vulnerable due to anthropogenic pressures. This study presents the first documented evidence of microplastics within mermaid’s purses, the protective structures nurturing embryonic sharks. Microplastic concentrations were quantified in egg cases from two oviparous shark species, Hasselt’s bamboo shark, Chiloscyllium hasseltii and coral catshark, Atelomycterus marmoratus. The results reveal that all examined egg cases contained microplastics, with significantly higher levels observed in A. marmoratus egg cases (21.42 ± 0.86 particles per egg case) compared to C. hasseltii (16.35 ± 1.82 particles per egg case). Additionally, a positive correlation between microplastic abundance and yolk mass suggests potential implications for embryonic development. Physico-chemical characterization identifies predominance of fibre morphology, dark-coloured microplastics, and rayon polymer type. These findings highlight the urgent need for targeted conservation strategies to mitigate the impacts of microplastic pollution on vulnerable shark populations and marine ecosystems. This study supports informed policies and concerted efforts to safeguard ocean health and preserve the integrity of apex predator populations, emphasizing the interconnectedness of marine ecosystems and the imperative of sustainable stewardship.