Studying the potential impacts of bottomfishing in the Northwest Hawaiian Islands Coral Reef Ecosystem Reserve

by Christopher D. Kelley and Rachel Shackelford

The Northwest Hawaiian Islands Coral Reef Ecosystem Reserve was created by an executive order from President Clinton in 1998. This reserve was designed to protect the unique natural resources of a chain of islets, atolls, submerged banks, and seamounts in the Hawaiian Archipelago extending over 1,000 miles northwest of the island of Niihau (Fig. 1). While it has the distinction of being the largest marine reserve in the United States, it is also the most poorly known, particularly below the depths accessible by SCUBA. That, however, is changing as various agencies are joining forces to use deep submergence vehicles for exploring and studying its strange and magnificent realms below 200 ft.

Until last year, only nine submersible dives had ever been conducted in this region. In September 2001 that number was more than doubled during a two and a half week cruise aboard the R/V Kaimikai-o-Kanaloa (KOK). A team of researchers led by NOAA's Hawaii Undersea Research Laboratory (HURL) and the National Marine Fisheries Service Honolulu Laboratory (NMFS-HL) made ten 8-hr daylight dives in the Pisces V submersible (Fig.2) on East French Frigate Shoals, Brookes Bank, West St. Rogatien Bank, Raita Bank, and a deep pinnacle north of French Frigate Shoals. The project involved 24-hour operations, so each evening, after the sub was recovered, the RCV-150 ROV (Fig. 3) was deployed for another 8 hours to obtain noctural observations. Finally, from 3 to 7 a.m., the KOK's Sea Beam multibeam sonar system was used to map tracks across and around the banks in an effort to determine their true geographic positions.

Over half of this work was conducted around West St. Rogatien and Raita Banks. In Clinton's executive order, special conditions were attached to these banks regarding their use by commercial bottomfishers. Specifically, fishing will be allowed to continue until 2003 while a study is conducted to assess its impacts on the ecosystem. HURL biologists, along with a team of researchers from NMFS-HL and the State of Hawaii's Department of Land and Natural Resources (DLNR), initiated the study with funding from the National Ocean Service (NOS). Submersible and ROV dives were used to survey known fishing sites on the banks. Identification and counts were made of all fish and invertebrates species, lost anchors and anchor lines, fishing gear, and trash that may have been left by the fishers. At specific locations, bait was put out near the sub to attract and document bottomfish species (Fig. 4). Fish around the bait stations were videotaped without any artificial light using a new CCD camera installed on the Pisces V (Fig. 5).