Spatial-temporal occurrence of microplastics in Sebastes melanops off the coast of Oregon

Katherine S Lasdin, Oregon State University, Fisheries and Wildlife, Corvallis, OR, United States, Anika Agrawal, Texas A& M Galveston, Marine Biology, Galveston, TX, United States, Jordan G Laundry, Oregon State University, Corvallis, United States and Susanne M Brander, Oregon State University, Corvallis, OR, United States
Increased plastic production and mismanagement of waste is widely documented to impact marine ecosystems. Microplastics are the most common plastic debris type and pose a hazard to organisms that ingest them. Opportunistic feeders, such as rockfish (Sebastes spp.), are susceptible to microplastic ingestion and are found along populated coastlines. Two life stages are being compared across several locations off the Oregon coast, either near / inside marine reserves or closer to populated areas. This is beneficial as the marine reserves are less than 10 years old in Oregon and will be assessed in 2023 to see if they are aiding in the protection of fish. Our work will determine whether plastic is being consumed at comparable amounts in both stages and if it could be bioaccumulating. The juvenile samples have been collected across 3 years and doing a temporal comparison can aid in determining if plastic pollution is increasing or changing across time. Digestive tracts were examined to determine whether they contained suspected microplastics, and undigested prey items from the stomach were analyzed separately. Data thus far show that the percent of adult fish obtained near populated areas and associated with marine reserves that contained suspected synthetics or microplastics was 10.3% and 26.7%, respectively. Fish caught near marine reserves contained more suspected microplastics than those sampled near a medium-sized coastal town (p-value = 0.016). Suspected microplastics will be confirmed by micro-Fourier transform infrared spectroscopy. These data show that nearshore species may be impacted by waste management shortfalls, or that plastics are being delivered via ocean currents from elsewhere. Continued research is needed to determine how much plastic is found in surrounding waters, the amount ingested or accumulated by other organisms in this food web, and how it impacts vital species in protected and more impacted areas to better understand the health of marine ecosystems.