Trends and drivers of debris accumulation on Maui shorelines: Implications for local mitigation strategies

• Evaluated debris accumulation trends at three geographically distinct Maui sites
• Wind and tide were the main driving forces for debris accumulation.
• Temporal variations in survey frequency show differences in accumulation rates.
• Plastic debris from both ocean- and land-based sources dominated at all sites.
• Local policy to mitigate debris depends on enforcement and consumer responsibility.

Marine debris, particularly plastic, is an identified concern for coastal areas and is known to accumulate in large quantities in the North Pacific. Here we present results from the first study to quantify and compare the types and amounts of marine debris on Maui shorelines. Surveys were conducted monthly between May 2013 and December 2014, with additional daily surveys conducted on Maui's north shore during January 2015. Debris accumulation rates, loads, and sources varied between sites, with plastics being the most prevalent type of debris at all sites. Large debris loads on windward shores were attributed to the influence of the North Pacific Subtropical Gyre and northerly trade winds. Daily surveys resulted in a significantly higher rate of debris deposition than monthly surveys. The efficacy of local policy in debris mitigation showed promise, but was dependent upon the level of enforcement and consumer responsibility.