Temporal and spatial variability of beach litter in Mangaluru, India.

Monthly litter samples were collected from three major beaches in Mangaluru from 2011-2016. Fishing litter persisted at the beaches, resulting in higher abundances by number (59%) and weight (33.4%) relative to all litter in 2016. In addition to plastics, foam comprised 7.14-11.0% of total litter. Significant positive correlations were observed between the amount of plastic on the beaches and rainy days, rainfall, and river discharge. The maximum river discharge coincided with an increase in plastic items on the beach. Yearly quantities of plastic items (p < 0.01), plastic bags (p < 0.001), and plastic footwear (p < 0.05), on the beaches were significantly different indicating clean-up activities reduced the litter quantity. Changes in total beach litter revealed that Panambur Beach, a fishing boat landing centre was the least changed, and thus appropriate incentive-based management options for the resident fishermen could result in collection and elimination of litter.