PROGRAMME

Marine litter monitoring and assessment is required under the EU Marine Strategy Framework Directive to prevent any harm on marine ecosystems and their biota. Sampling to evaluate effects of marine litter, including microdebris, in top predators is difficult. Usually, microdebris is examined in the gastro-intestinal tract of stranded dead animals. However, the population of the endangered Mediterranean monk seal is too small for obtaining sufficient samples. The present study implemented for the first time a non-invasive technique for collecting monk seal samples to assess the microdebris ingestion in a systematic manner. A total of 12 samples of monk seal faeces were collected from marine caves in Zakynthos Island, Greece (INTERREG MED project “Plastic Busters MPAs”). A total of 166 particles were identified; 77% of the particles were smaller than 3 mm but a piece of net larger than 5 cm was also found. The majority of particles were filaments (84%), and only one sphere was found. Faeces contained on average 14 particles per sample, half of the average in previous studies using the whole digestive tract. The use of faeces represents an effective non-invasive tool to assess the incidence of microdebris and the trophic transfer of these pollutants.