Marine Debris Monitoring and Cleanup Underway on Coral Reefs of the Papahānaumokuākea Marine National Monument

September 1, 2009
Removal of derelict fishing gear is a demanding task but essential for reducing risks to marine life in the NWHI coral reef ecosystem.
Removal of derelict fishing gear is a demanding task but essential for reducing risks to marine life in the NWHI coral reef ecosystem.

The NOAA Ship Oscar Elton Sette embarked September 1, 2009, on a 30-day mission to the Northwestern Hawaiian Islands (NWHI) to monitor and remove derelict fishing gear from remote coral reef habitats of the Papahānaumokuākea Marine National Monument. Derelict fishing gear and other marine debris is harmful to marine life, particularly in coral reef ecosystems of the NWHI. This is the first of two expeditions this calendar year directed towards derelict fishing gear removal by the NOAA Pacific Islands Fisheries Science Center’s (PIFSC) Coral Reef Ecosystem Division (CRED).

The Monument's diverse coral reef ecosystems are home to over 7,000 unique marine species. Besides supporting a rich assemblage of corals, fish, invertebrates, algae, and other reef inhabitants, the shallow-water reef environment provides critical habitat for protected species such as the threatened green sea turtle, the endangered Hawaiian monk seal, and various seabirds.

The derelict fishing gear consists of fishing nets or net fragments (from gill nets, trawl nets, etc.), fishing lines, rope, and other components of fishing gear discarded, lost or abandoned at sea by the multi-national fishing fleets of the Pacific. Swept along in the ocean currents, the debris accumulates on sensitive reefs and nearshore habitats of the NWHI. Derelict fishing gear can smother, abrade, and destroy coral reefs and their inhabitants and fatally entangle monk seals, turtles and other marine life. It is also a potential vector for the introduction of non-endemic species and is hazardous to boat navigation.

Under the leadership of expedition Chief Scientist Kyle Koyanagi, a crew of 17 CRED scientists with specialized training in scuba diving will conduct in-water surveys of marine debris at Maro Reef, Pearl and Hermes Atoll, and Kure Atoll and remove the debris they find. They will focus on areas known to have high densities of derelict fishing gear. Debris removal operations will also be conducted along the beaches and shores of Laysan Island, Lisianski Island, Pearl and Hermes Atoll, and Kure Atoll to reduce the risk of entanglement for protected marine mammals and other wildlife that utilize these shoreline locations.

Derelict fishing gear, such as lines and rope, can entangle sea turtles, leading to fatal injuries.
Derelict fishing gear, such as lines and rope, can entangle sea turtles, leading to fatal injuries.

In addition to the marine debris surveys and removal operations, the scientists will conduct oceanographic observations in the region. Oceanographic instruments, including Subsurface Temperature Recorders (STRs) and Ecological Acoustic Recorders (EARs) will be inspected, deployed and/or replaced at Maro Reef, Pearl and Hermes Atoll and Kure Atoll. While the Sette is in transit along the NWHI, the scientific crew will deploy a CTD instrument to measure conductivity and temperature variation from the sea surface to the ocean depths at designated permanent sampling stations. The CTD data will be added to a NOAA database of ocean measurements important for improved understanding of local and regional ocean dynamics and the impacts of climate change.