Anthropogenic Particle Ingestion in the Starry Round Ray Urotrygon asterias : High Occurrence Independent of Biological and Spatial Predictors

The ingestion of anthropogenic particles by marine organisms is now widely reported, yet rays and skates remain poorly studied, especially in tropical regions. Particle ingestion was examined in the starry round ray ( Urotrygon asterias ), a common bycatch species found in the Gulf of California shrimp fishery. We analyzed the digestive tracts of 114 individuals collected in July and August 2019 to determine how frequently particles were present, how many were ingested, and what materials they were made of using µFTIR–ATR spectroscopy. We also tested whether sex, body size, diet, or capture zone influenced ingestion patterns. Anthropogenic particles were found in 82% of the rays, with a mean of 2.35 ± 2.21 particles per individual examined ( n  = 114). Almost all particles were fibers (98.9%). Natural fibers dominated, with cellulose and cotton together accounting for 84% of all particles, followed by synthetic polymers (13.4%, mainly polyester) and semisynthetic rayon (2.2%). Particle abundance and particle composition did not differ between males and females across size classes and among capture zones, and no clear association with diet composition was observed. Although diet varied among regions, particle ingestion patterns did not differ significantly by region. These results suggest that particle ingestion in this species may be consistent across the biological and spatial groups evaluated, although unbalanced sample sizes or unmeasured environmental factors may have limited the ability to detect real differences. The dominance of textile‐related fibers points to everyday human activities as a possible source of exposure in this coastal system, though their specific origin would require confirmation through direct source‐tracking analysis. This study provides the first record of anthropogenic particle ingestion in the genus Urotrygon and offers baseline information for the Gulf of California.