Captive dolphins face higher levels of microplastic pollution than wild individuals

Traditional research on microplastics in cetaceans has largely overlooked the extraction methods and their occurrence in multi-tissues. Here we present a reliable framework for extracting microplastics from multi-tissues of cetaceans, achieved through methodological comparisons and stringent quality control measures. Furthermore, a case study assesses microplastics in wild and captive pantropical spotted dolphins (Stenella attenuata). The high microplastic detection rates (80% − 100%) across various tissues underscore the contribution of microplastics from atmospheric, aquatic, and dietary sources to cetacean exposure. The microplastic abundance and detection rate in S. attenuata show a logistic relationship, indicating extensive pollution. Wild individuals exhibited more diverse microplastics (0.67 ± 0.12) than their captive counterparts (0.59 ± 0.09). Conversely, captive individuals highlighted higher pollution levels (0.67 ± 0.47 items g−1) than wild individuals (0.19 ± 0.08 items g−1). These findings provide valuable baseline data and perspectives for studying microplastic pollution and informing management strategies for marine mammals. Dolphins in captivity are exposed to higher levels of microplastics with lower diversity than wild dolphins, according to analyses based on a framework for sampling microplastics from cetacean tissues.