Short-tailed shearwater (Ardenna tenuirostris) plastic loads and particle dimensions exhibit spatiotemporal similarity in the Pacific Ocean

Abstract

Short-tailed shearwater (Ardenna tenuirostris) stomach contents provide some of the earliest documentation of oceanic plastic pollution, one of the longer data series of seabird stomach samples, and the species' wide range in the North and South Pacific provides comparative data for the Pacific Ocean. A mortality event in the North Pacific in 2019 provided additional data for spatiotemporal comparisons. In the North Pacific the percent occurrence, mass, and number of pieces were similar since the first records in the 1970s. Particle size increased slightly reflecting a transition from uniform pre-manufactured pellets in initial reports to irregular user fragments in recent reports. Contemporary North and South Pacific plastic loads and particle dimensions were similar. A lack of temporal or spatial difference affirms previous conclusions that plastic retained in short-tailed shearwaters and other Procellariiformes is related to body size, gastrointestinal structure, and species' preferences rather than the availability of oceanic plastic.

Keywords: Ardenna tenuirostris; Pacific Ocean; Plastic; Seabird.