In 1998 the Hawaii Undersea Research Laboratory conducted research in the NW Hawaiian Islands, using its submersible Pisces V and ROV RCV-150 from their mother-ship R/V "Ka'imikai 0 Kanaloa" in support of the NURP project "Evaluating deep-water benthic and demersal communities in relation to foraging activities of the endangered Hawaiian monk seal" conducted by Frank Parrish (NMFS HI), Richard Grigg (Oceanography, UH), & James Parrish (USGS).

Plans to harvest precious coral beds commercially in the Northwestern Hawaiian Islands raised concern of impacts to resident monk seal populations. French Frigate Shoals (FFS), Hawaii is the largest island population of monk seals, comprising 34% of the total population of this endangered species and has been studied extensively. A decade of poor survivorship and observed emaciation in young and mature seals has prompted theories of reduced forage availability at the atoll. Diving patterns of foraging FFS seals indicate a percentage of effort is invested at sub-photic depths (>300 m) where precious corals could occur. Movement patterns of 30 seals fitted with satellite tags identified only two locations where seals frequented deep depths. The HURL submersibles Pisces V and the RCV-150 were used to survey these locations, and precious coral beds were found at both. The success at locating coral beds at the center of the seals forage activity contrasts 11 earlier submarine surveys done by HURL in 1984 around FFS atoll which found no coral beds. The probability of finding deepwater coral beds at the seal forage sites by chance alone is very low. Seals were specifically visiting the coral beds.

The occurrence of precious coral beds is patchy and the distribution of the beds is poorly known. Fish are attracted to and shelter within the beds including some species of eels that commonly associate with the largest deepwater corals. Seals may be seeking out coral beds to feed on resident fish thus improving their feeding success and justifying the energetic investment of deep foraging. With ages of corals ranging to as much as 75 years, harvest of large coral colonies could alter habitat for decades and perhaps make prey less accessible to foraging seals. Managers and industry have worked together to amend harvest regulations to protect the seals forage habitat. A ban on the use of nonselective harvest gear and preservation of some identified coral stands were some of the regulations proposed to maintain the seal's access to its forage base.

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Last update on 11 April 1999