Applying a Macro Lens to Microplastics: Modeling Microplastic Ingestion Risk to Humpback Whales in the Chesapeake Bay

Plastic waste is an increasing threat to marine environments, with an estimated 1.2-2.4 million metric tones of waste entering marine systems through rivers yearly. Plastic debris can fragment into smaller particles, classified as microplastics (particles < 5mm), due to weathering, oxidation, and other processes. When consumed by an organism, MPs can be retained in the stomach, resulting in false satiation, and may lead to translocation that creates damage at the cellular level. Filter feeding megafauna such as humpback whales are at risk of directly ingesting MPs suspended in the water column and may accumulate particles indirectly by consuming contaminated prey. Based on previous MP ingestion risk assessments, fish-feeding humpback whales in the California Current consume approximately 200,000 pieces of MP per day. While MP ingestion risk has been documented for humpback whales in the California Current, less is known about the risk in the Mid-Atlantic, specifically within the Chesapeake Bay. Determining exposure route and the extent of bioaccumulation are important first steps to assessing risk for individuals and populations. I will model microplastic ingestion risk to humpback whales in the Chesapeake Bay by incorporating CATS (Customized Animal Tracking Solutions) tag data, feeding rates, prey density, and empirical values of MP contamination in collected prey and water column samples. I will use heat assisted chemical digestion and filtration methods to extract the MPs in these samples. I will photograph and record size, color, and type (e.g. fragments, foams, and fibers) of the isolated MPs and perform Fourier-Transform Infrared Spectroscopy (FTIR) analysis to identify their source. Studying MPs across trophic levels is important for highlighting potential entry pathways for marine debris, critical for protecting natural resources, and guiding informed management implementation.