2018 Volume 41 Issue 4 Pages 107-113
Microplastics pollution has recently drawn worldwide attention, and may have negative effects on ecosystems. Microplastics are plastic smaller than 5 mm. This study documents microplastics larger than 100 μm in seven fish species from five Japanese bays and Lake Biwa. 197 fish individuals were examined. A total of 140 microplastics particles were found in the digestive tracts of 37.6% of all fish. All species except Sardinella zunasi had ingested microplastics in all areas. The mean number of microplastics particles was 1.89±1.41 per individual fish. Most microplastics were polypropylene (40.7%) and polyethylene (35.0%) as identified by Fourier Transform Infrared Spectrometer (FT-IR) . The median of the mean sizes of microplastics was 543 μm as measured using a microscope and digital camera. The fish species were divided into filter feeders and the others on the basis of modes of ingestion. 54.6% of 97 individuals of filter feeders had ingested microplastics, and the total number of particles was 112. The mean number of microplastics particles in filter feeders was 2.11±1.54 per individual fish. 21.0% of 100 individuals of the others group had ingested microplastics, and the total number of particles was 28. The mean number of microplastics particles in the others group was 1.33±0.80 per individual fish. These results indicated that modes of ingestion influence the fish’s ingestion of microplastics.