High Seas GhostNet Detection Project
Pacific Region; 2005
Large fishing vessels can lose fishing nets that are several miles long in the ocean. When these nets are lost, they continue to fish, catching anything that is in its path and cannot escape through the mesh. Because they are made of monofilament, a type of synthetic, they do not biodegrade. As they are moved by ocean currents, many of these nets, called “ghostnets,” eventually wash up on shore or become entangled in coral reef or other habitats.
Removing a floating net from the ocean is much easier than removing that same net from the coral reefs of the Northwestern Hawaiian Islands; the problem is to locate concentrations of debris in the ocean that justify sending a ship for removal.
Removal of lost and abandoned high-seas ghostnets from the open ocean would reduce the rate of species entanglement (including threatened and endangered) at sea and reduce the amount of these materials on coral reefs and beaches.
For the last several years, the NOAA Environmental Technology Laboratory (now part of the Physical Sciences Division of the Earth System Research Laboratory), the NOAA Oceanic Research and Applications Division, the NOAA Pacific Fisheries Environmental Laboratory, and Airborne Technologies, Inc. have been developing a technique to efficiently locate ghostnets in the open ocean, focusing on the Pacific. Convergence zones are identified using data from satellites, and aircraft are directed to these zones to search for debris using remote sensors (high-speed cameras and video) on the aircraft and with spotters (people), also on the aircraft. Field tests of this technique, using satellite data to direct instrumented aircraft searches, have demonstrated that debris could be successfully located in convergence regions along the coast of Alaska and in the large subtropical convergence zone north of Hawaii.
The High Seas GhostNet Detection Project is developing a method to efficiently locate ghostnets in the open ocean for at-sea removal.
The field tests were made in March and April, 2005. About 2,000 individual pieces of debris were detected in three overflights of specific areas. These pieces included over 100 nets or pieces of net. Analysis of this information is currently being done to see if the satellite data alone are sufficient to locate concentrations of debris. This would allow ships to be directed to areas of high marine debris concentrations, without the need for aircraft to conduct overflights to verify the presence of debris.
This project is housed within NOAA's Office of Oceanic and Atmospheric Research, Earth System Research Laboratory, Physical Sciences Division; NOAA's Satellite Service, Oceanic Research and Applications Division; NOAA's National Marine Fisheries Service, Pacific Fisheries Environmental Laboratory.