Microfibers in Mytilus species(Mollusca, Bivalvia)from Southern California Harbors, Beaches, and Supermarkets

Plastic microfibers are an emerging threat to terrestrial and aquatic habitats worldwide. They are equivalent in size to planktonic organisms, making them available to a range of invertebrates. Bivalve mollusks can ingest and accumulate plastics via digestion and adherence to soft tissue. We determined the frequency and characteristics of microfiber pollution from wild Mytilus californianus and farmed Mytilus edulis populations that were collected from southern California harbors, beaches, and supermarkets (n=4 per site). Mussel organic matter was dissected using 30% H2O2. After adding a saline solution to separate the fibers, the liquid was filtered by vacuum filtration. The remaining fibers were examined with a magnification of 1~8x. In this short-term survey, the abundance of microfibers by sample and by shell length showed a significant difference between the harbor and beach sites. However, there was not a significant difference between the wild and farmed mussels examined. This study revealed widespread microfiber pollution and uptake by mussels in these locations and reinforces how bivalves can be used as a bioindicator of microfiber pollution.KEYWORDS: Microplastic; Microfiber; Mytilus; Biomonitoring; Bivalvia; Seafood; Human Health