An analysis of global tracking data for 77 petrel species has revealed a concerning fact: a quarter of all plastic encountered by these seabirds during their search for food is found in remote international waters. This highlights the need for international collaboration to address the issue. The study, which combined tracking data for numerous seabird species with global maps of plastic distribution, demonstrates that plastic pollution poses a threat to marine life that extends beyond national boundaries. The main risk comes from gyres—large rotating ocean currents—where massive amounts of plastic accumulate from various countries and boats. Seabirds, including petrels, often mistake plastic fragments for food or ingest it indirectly through their prey, leading to injuries, poisoning, and even starvation. Petrels are particularly vulnerable because they struggle to regurgitate the plastic and often unknowingly feed it to their chicks. Moreover, the presence of toxic chemicals in plastics further endangers seabirds. Given their significance in oceanic food webs and their widespread distribution, petrels are crucial “sentinel species” for assessing plastic pollution risks in the marine environment.
Climate change, bycatch, competition with fisheries, and invasive species already threaten petrels and other species with extinction. The exposure to plastics may further reduce their resilience to these threats. The study highlights that even species with low exposure risk have been found to consume plastic, indicating a global problem for seabirds. The researchers emphasize the necessity for international cooperation to combat plastic pollution in the world’s oceans, as plastic debris often ends up far away from its original source due to ocean currents. The Mediterranean Sea and the Black Sea account for over half of petrels’ global plastic exposure risk, although only four petrel species forage in these busy enclosed areas.
The study, led by a partnership between the University of Cambridge, BirdLife International, and the British Antarctic Survey, involved collaboration with Fauna & Flora International, the 5 Gyres Institute, and over 200 seabird researchers in 27 countries. By overlaying global location data from tracking devices onto existing maps of marine plastic distribution, the researchers determined the areas where the birds are most likely to encounter plastics during their migrations and foraging journeys.
Various threatened species, such as the Critically Endangered Balearic Shearwater, the Hawaiian Petrel, and several Vulnerable species, scored high for plastic exposure risk. While the population-level effects of plastic exposure are not fully understood for most species, the study emphasizes the precarious situation of many petrels and other marine species. The findings will contribute to conservation efforts aimed at addressing the threats faced by seabirds at sea. The study was published in the journal Nature Communications.
Source: University of Cambridge