Marine Pollution Bulletin
Nineteen sites along the Caribbean coast of Panama were examined for stranded debris. Beach transects, collections, and experiments were used to examine debris abundance, composition, type, possible sources, and dynamics (longevity, net changes on cleared and undisturbed beaches). Most debris was polystyrene foam (styrofoam) and other plastics (82%) related to consumer or household use. Medical waste was present, but rare. The most frequent country of origin was Panama (43%), with other countries of the Caribbean region contributing 31%, the US 16%, and the remaining 10% from more distant sources. Beach debris was more abundant at sites near Colon than at sites 30 km or more downcoast. Mark/recapture experiments showed an average residence time on beaches of less than 1 year. Significantly more marked items disappeared from transects during dry than wet season. Repeated monitoring of uncleared beaches showed that debris generally accumulated slowly over time, but occasionally showed sharp increases or decreases. Experimentally cleared beaches regained about 50% of their original debris load after 3 months. Site location, weather and occasional large inputs (dumping, washouts, etc.) appeared to be the most important factors controlling debris on Panama's Caribbean beaches.