Boland, R., Zgliczynski, B., Asher, J., Hall, A., Hogrefe, K., Timmers, M.

Dynamics of debris densities and removal at the Northwestern Hawaiian Islands coral reefs

2006

Smithsonian Institution, National Museum of Natural History

Atoll Research Bulletin

543

461-470

"Previous marine debris studies in the Northwestern Hawaiian Islands (NWHI) have focused on the density, type, and tonnage of debris in various reef and island habitats. Cleanup efforts have grown from a single ship working for a small amount of time to multiple vessels for extended periods. A key element to determining the effectiveness of these efforts is the decline of debris density relative to accumulation rate in these habitats. Study sites were monitored and cleaned for up to 5 years from 1999 to 2003. We measured densities, estimated accumulation rates and projected the number of days required to completely clean the atolls. Initial clean-up efforts (1999) at two atolls removed 28-63 debris items per km2 with a total cleanup of the atolls estimated to require 45 years. In subsequent years, improved techniques and greater effort has resulted in an overall pattern of decreasing debris densities, projected debris levels and projected workdays to completely clean the atolls. In the final year (2003), densities at the same two atolls ranged from 6-12 debris items per km2 with cleanup estimated to require 13 years. This pattern suggests the rates of debris removal within the study sites have surpassed the rate of debris accumulation and removal activities are effectively reducing debris levels. To effectively deplete the debris below current levels, an effort should be made to decrease accumulation rates by intercepting debris at sea and preventing loss and discarding of fishing gear."

FY2003 CRCP Project ID 1224; Project Title: Marine Debris Removal from NWHI; Principal Investigator: Rusty Brainard