Microplastic data from surface waters and in stream-rearing steelhead trout (Oncorhynchus mykiss) in a rural coastal California stream

This dataset supports the study of microplastic pollution in Scott Creek, a small coastal watershed in California, USA. It includes measurements of suspended microplastic in surface waters and the gastrointestinal (GI) tracts of juvenile Steelhead Trout (Oncorhynchus mykiss). Data include microplastic particle counts, types (fibers, fragments, shards, foams), colors, and sizes (<5 mm), collected across multiple sites and months. The dataset provides baseline information on microplastic occurrence in a minimally urbanized, salmon-bearing stream, offering critical context for evaluating ecological risks to native fish populations.