Net Analysis

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Marine debris divers with net collected from Kure Atoll, NWHI

Net analysis is a data collection technique used to measure various parameters of the nets collected. These data will be used to determine the source fisheries from which the derelict fishing gear is accumulating on the Hawaiian Archipelago. The identification of the fishery sources of the removed net is a critical step in attempting to prevent future anthropogenic damage to the NWHI. Clean-up efforts are a successful short-term mitigation activity but will not continue indefinitely due to time, cost, and logistical difficulty. If sources are identified, we hope that through outreach and education, intentional dumping of fishing gear into the oceans will come to an end.

Data Collected

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Marine debris

Every tenth boatload of debris is analyzed in detail. The nets are brought back to the ship where they are untangled, sometimes a long and arduous task! Then the nets are separated into piles based on net type and each pile is then weighed. A small sample, about 6 in by 6 in is taken from each net type, and detailed data are collected including: net type, mesh size, twine diameter, net color, material, construction type, number of strands, and twist direction. Each sample and all data collected are catalogued and saved for future analysis.

Current Status

Project efforts are now focusing on developing and implementing the following four primary actions in an effort to identify source fisheries responsible for the derelict fishing gear that is damaging coral reef ecosystems of the NWHI. We are seeking solutions to this problem through international, multiagency and community engagement.

  1. Examine archived marine debris samples collected in the NWHI to determine fishery, country of manufacture and, if possible, country of use.
  2. Develop a comprehensive user-friendly marine database using computer software integrating debris characteristics such as eye size, twine diameter, knotting type, etc. with fishery information.
  3. Create a debris reference key with data and digital images for widespread distribution among net manufacturers and user groups.
  4. Assist the Asia-Pacific Economic Cooperation Fisheries Working Group in the planning and implementation of a derelict fishing gear workshop bringing fishermen, industry leaders, policy-makers, and managers from Pacific states and representatives of the International Coastal Cleanup together to identify priorities and solutions to remove marine debris from Pacific waters.