Microplastics Are Prevalent in Striped Bass and Shiner Surfperch Tissues across San Francisco Bay, California

The ingestion of microplastics by fish is widely documented, but the drivers of contamination and the movement of particles within organisms are still not well understood. We investigated microplastic contamination in sport fish caught from San Francisco Bay in California, USA. We compared microplastic contamination in striped bass (Morone saxatilis) and shiner surfperch (Cymatogaster aggregata). We observed an average of 5.9 ± 5.6 (Std Dev) microplastics per fish, with significantly higher overall contamination in striped bass but higher concentrations (microplastics/gram of tissue) in shiner surfperch. For each, we considered contamination relevant to their consumption by recreational anglers. For striped bass, where only the fillet is typically ingested, we found that contamination among tissues differed significantly (on average 3.8 ± 3.1 microplastics/fish fillets). Shiner surfperch, which are typically consumed whole, had an average body burden of 9.1 ± 1.2 microplastics/fish. Contamination varied significantly (p-value < 0.0001) among sampling locations for shiner surfperch, with the highest amounts observed near urban centers (no significant spatial pattern was observed for striped bass). Our findings show microplastics in tissues beyond the gastrointestinal tract, posing concerns for fish health and suggesting that fish caught from San Francisco Bay are a pathway for human consumption of microplastics.