Giant predators, tiny pollutants: Exploring anthropogenic microparticles in the feces of white sharks (Carcharodon...

The presence of anthropogenic microparticles (particles <5 mm in any dimension) is being increasingly reported, yet little is known about their abundance, distribution, and bioavailability in marine environments. Microplastics (plastic polymers <5 mm) are persistent anthropogenic microparticles that contaminate marine environments and often enter food webs through ingestion. Sharks are sentinel species in the ocean, yet studies characterizing microparticle, or more specifically microplastic, ingestion in sharks are scarce. The objectives of this study were to describe and quantify microparticles in the feces of white sharks (Carcharodon carcharias). Samples were obtained from a total of 35 white sharks, including seven young-of-the-year, 17 juveniles, six subadults, and five adults inhabiting the Western North Atlantic Ocean. Microparticles were isolated, analyzed with a stereomicroscope to determine size, shape, and color, and characterized by polymer type using Fourier transform infrared (FTIR) spectroscopy. Anthropogenic microparticles were detected in all fecal samples. The mean ± standard deviation of microparticles per sample was 7.5 ± 4.2, and of those, 1.4 ± 1.3 were microplastics. No significant differences in the abundance of microplastics were detected by age class, sex, or collection location, year, or seasonal residency; however, differences in microparticle composition were observed across collection locations. Rayon and cellulose were the most abundant microparticle polymers, and polyester, polypropylene, and nylon were the most abundant microplastic polymers. White, black, and blue were the most common colors of microparticles and microplastics. This research contributes much-needed data from a top-level predator in marine ecosystems. Assessing microplastic content in white shark feces can serve as a non-lethal indicator of environmental contamination.