Microplastics in Cetaceans Stranded on the Portuguese Coast

Area of Science:

• Marine Biology
• Environmental Toxicology
• Ecotoxicology

Background:

• Microplastic pollution is a growing global concern, particularly in marine ecosystems.
• Small cetaceans are valuable bioindicators of ocean health.
• Understanding microplastic loads in marine fauna is crucial for assessing ecological risks.

Purpose of the Study:

• To characterize microplastics in stranded cetaceans along the Portuguese coast.
• To investigate the relationship between biological variables and microplastic abundance.
• To assess potential health implications of microplastic ingestion in cetaceans.

Main Methods:

• Laboratory analysis of microplastics in the intestines of 38 stranded cetaceans.
• Digestion methods were adapted based on sample organic matter content.
• Statistical analysis to test the influence of species, sex, and body condition on microplastic loads.

Main Results:

• Microplastics were detected in 92.11% of the analysed cetaceans.
• Harbour porpoises exhibited significantly higher median microplastic counts than common dolphins.
• No significant influence of sex or body condition on microplastic abundance was observed.

Conclusions:

• Diet and habitat likely explain microplastic load differences between cetacean species.
• Current microplastic levels are unlikely to cause acute sublethal effects.
• Standardized protocols are needed for future comparative microplastic analysis in marine biota.