An Integrated Approach to Assessing the Potential of Plastic Fishing Gear to Release Microplastics

Abandoned, lost, or discarded fishing gear (ALDFG) poses significant environmental threats, namely contributing to microplastic (MP) pollution. However, the release of MPs from ALDFG remains poorly studied, despite its crucial role in understanding plastic pollution in marine ecosystems. This study is, to the best of our knowledge, the first to assess the environmental impact of ALDFG as a source of MPs, using an integrated approach combining laboratory experiments, in situ field trials, and environmental surveys. Laboratory tests showed that in the presence of light and sediment, braided polyethylene net released 1 fibre after incubation, demonstrating that the studied plastic fishing nets had the potential to release MPs. In situ experiments in a semi-enclosed marine environment did not show a clear influence of submerged fishing nets on water MPs, due to the high MP contamination in the selected location (5322 ± 4936 MP m⁻³). Nonetheless, at ALDFG hotspots off northwest Portugal, an increased presence of MPs in water samples compared to locations without ALDFG suggested potential MP release. These findings demonstrate the potential of ALDFG to act as a source of MPs and showcase the need for further studies, in order to comprehensively investigate the degradation of different plastic fishing nets in the field. Reducing ALDFG pollution is critical to mitigating its environmental impact and preserving marine ecosystems.