By Kevin O’Brien
Staff members of the marine debris team of the PIFSC Coral Reef Ecosystem Division (CRED) are near the end of a 21-day mission to survey and remove marine debris at Midway Atoll in the Northwestern Hawaiian Islands. As of April 12, after 13 days of operations, a 9-person team had removed nearly 9 metric tons (8991 kg) of derelict fishing gear, plastics, and other debris items, including a fishing boat, from the reefs and shorelines of Midway Atoll, one of several atolls and islands of the Papahānaumokuākea Marine National Monument and World Heritage Site.
The team is well on its way to completion of the required towed-diver surveys, despite some challenging wind and swell conditions. During in-water operations, towed divers visually surveyed reefs for derelict fishing gear. When derelict fishing gear was spotted on a reef, the divers carefully cut the debris free of the reef bottom and hauled it up over the side of one of the 17-ft Avon inflatable boats used to tow divers and transport debris. Over the course of the last few weeks, the team has conducted towed-diver surveys on the northern, northeastern, and southwestern fringing reefs of Midway Atoll. A pilot study of debris accumulation rates is also part of the operations this year: preselected regions of this atoll’s fringing reef are being surveyed for derelict fishing gear.
In addition to in-water activities, shoreline survey and removal operations have been conducted on all 3 of Midway’s islands: Sand Island, Spit Island, and Eastern Island. All debris items >10 cm in size were cleaned from the shoreline areas of these islands and transported back to the team’s headquarters on Sand Island. There, the debris was weighed, sorted, and tallied by debris type. For a side project, one marine debris standing-stock survey was conducted on each of the 3 islands of Midway Atoll. During these surveys, researchers recorded all debris items ≥2.5 cm in size observed within randomly selected transects on a beach. These data will be added to the national marine debris database maintained by the NOAA Marine Debris Program.
On April 7, the team successfully removed a 23.5-ft fishing boat from an area above the shoreline on the remote southeastern corner of Eastern Island. According to U.S. Fish and Wildlife Service personnel, this fishing boat was first noticed stranded on the beach in November 2012. At that time, the boat was cleared of any biofouling organisms and moved up into the vegetation above the high tide line. The writing on the bow of this fishing boat was relayed by the NOAA Marine Debris Program to the Consulate-General of Japan in Honolulu, and staff members there, working with their colleagues in the Government of Japan, confirmed the boat as lost during the March 2011 tsunami event in Japan. This boat is the third marine debris item found in Hawai`i that has been confirmed from the tsunami in Japan.
Together, the 9 members of the CRED team were able to muscle the 770-kg boat from the vegetation line down to the water’s edge, using logs and old pipes as rollers under the hull. Next, a tow line was connected to the bow, and one of the team’s Avon boats towed the fishing vessel off the shoreline into deeper water and then the nearly 5 km across the channel to Sand Island. The vessel was brought alongside the seawall in the inner harbor of Sand Island and lifted from the water onto the concrete of the old seaplane tarmac at the eastern end of this island. This boat now is staged on the tarmac with the rest of the collected marine debris and awaits shipment to Honolulu.
The team found another notable item potentially related to the Japan tsunami on the southwestern corner of Sand Island on April 6during shoreline surveys. The item was a large pallet tub made of blue plastic similar to bins used in seafood shipping. Tomoko Acoba, a member of the marine debris team, was able to translate the writing on this tub. It read “Yamanaga Suisan,” the name of a fisheries company located in Ishinomaki City, Japan, a town hard-hit by the 2011 tsunami. This information was sent to the regional coordinator of the NOAA Marine Debris Program, who is working with the Consulate-General of Japan in Honolulu and waiting for confirmation on whether or not this item is indeed related to the tsunami.
With only a few more days left that are slated for marine debris operations before they return to Honolulu, the team members are working harder than ever to ensure they leave Midway Atoll a cleaner place than it was when they arrived!