Seabirds as indicators of distribution, trends and population level effects of plastics in the Arctic marine environment. Workshop Report

Plastic pollution is a global and increasing threat to ecosystems. Plastics in the oceans are unevenly distributed, are transported by currents and can now be found in the most remote environments, including Arctic sea ice. The entanglement of wildlife by large plastic debris such as ropes is an obvious and well documented threat. However, the risks associated with the ingestion of smaller plastic particles, including microplastics ( 1mm found in the stomachs of dead (beached or bycaught) birds are quantified. With the origin of these birds being unknown, it is, however, impossible to assess how plastics affect populations even of this one monitored species, let alone for other seabird species that differ in their foraging behaviour and risk to ingest plastics.

This report sums up the results of a workshop which aimed to identify possibilities for long-term monitoring of (micro-) plastic ingestion by seabirds in the framework of SEAPOP, the basal programme monitoring the performance of Norwegian seabird populations (www.seapop.no). The key conclusions were: 1) There is a need for baseline information on plastic ingestion across all seabird species to identify which species and populations are most suitable for monitoring. To obtain this information, the best approach is to investigate the stomach contents of dead birds (i.e. comparable methodology across all species). For long-term monitoring, not only species with high plastic ingestion are of interest, but also those with low plastic prevalence. 2) In the absence of information from (1), eight species that are complementary in their foraging behaviour and have a wide distribution range were selected as preliminary species of interest to monitor plastic ingestion. 3) For minimally invasive monitoring, regurgitates, fresh prey items and faeces are most suitable; 4) More information on prevalence of plastic ingestion is needed to identify optimal sample sizes for long-term monitoring. We therefore highlight the need for several pilot studies before establishing a plastic monitoring protocol within SEAPOP.