B. P. Bishop Museum
Exploration and Discovery

The Coral-Reef Twilight Zone

Palau 'Twilight Zone' Expedition, 4-19 May 1997

Daily Log Reports

Click on any of the
dates shown below
for a report on that
day's diving activities,
including dive profiles
and photographs of
new discoveries.

4 May 1997
5 May 1997
6 May 1997
7 May 1997
8 May 1997
9 May 1997
10 May 1997
11 May 1997
12 May 1997
13 May 1997
14 May 1997
15 May 1997
16 May 1997
17 May 1997
18 May 1997
19 May 1997

Rebreather Totals
Discoveries: ~38


Expedition Abstract:
The purpose of this expedition is to search for new species of organisms which dwell on deep coral reefs. Due primarily to constraints of existing technology, coral reef habitat at depths between about 200 and 500 feet (60-120 meters) remains almost entirely unexplored. This zone, which has come to be known as the coral-reef 'Twilight Zone', spans the biologically important gap between the highly complex and diverse shallow coral reef environment, and the comparatively sparse abyssal environment. The use of advanced, mixed-gas diving equipment called 'Rebreathers' will enable us to descend to depths of 500 feet or more, allowing us to explore habitats not easily accessible to undersea researchers.

This web site contains additional information about this expedition and related topics. During the course of the expedition, log reports and photographs of new discoveries will be added to this page on a daily basis. At left is a list of all expedition dates. Click on them to see that day's log report. Also at left are totals of number of rebreather dives conducted, numbers of hours spent underwater by rebreather divers, and number of new biological discoveries.

This expedition and other aspects of coral-reef Twilight Zone exploration were on display in the Ocean Planet exhibit, hosted by Bishop Museum from May 24 through October 5, 1997. This exhibit, developed by Smithsonian Institution's National Museum of Natural History, was expanded with additional displays featuring ocean-related issues concerning Hawai‘i.

Expedition Sponsors
  The following companies and organizations provided assistance and/or support during this expedition:
Discovery Channel   The majority of funding for this expedition was provided by The Discovery Channel, in conjunction with Canal+ Network in France. An award-winning documentary film featuring this expedition, entitled Mysteries of the Twilight Zone, was first broadcast in April of 1998.
Toshiba America, Inc.   Tecra-740Several important objectives of this expedition (including the daily log reports) were made possible through the generous support of Toshiba America, Inc., who provided a Tecra-740 notebook computer.
Cis-Lunar Development Laboratories   This expedition would not have been possible without the Herculean efforts of Richard Nordstrom, Bill Stone, Nigel Jones, and Michael Stevens, of Cis-Lunar Development Laboratories, Inc. Thanks guys! Awesome machine.
DiveComm   Special thanks are owed to DiveComm, makers of electronic underwater wireless communication systems, who loaned an assortment of valuable equipment for use on this project.
Coral Reef Research Foundation   Dr. Patrick Colin and Lori Colin, Directors of the Coral Reef Research Foundation in Palau, were instrumental in assisting the organization of this expedition and in providing logistical support. Without their help and support, this expedition would have been impossible.
Body Glove   Many thanks to Body Glove, who provided custom wetsuits to expedition participants. Even in the warm tropics, the water temperature is cold down deep, and with dive durations exceeding 4 hours, thermal protection is important. The Body Glove wetsuits are ideal.
LavaVideo Productions   LavaVideo Productions loaned this project a digital video (DV) camera and underwater housing for, enabling both underwater videography at depths to 330 feet, and the capturing of digital images of fishes collected so that those images could be included on this web page.
NiteRider   NiteRider supplied underwater lighting systems at cost for use during this expedition. The head-mounted dual bulb lights enable us to keep both hands free to collect specimens, while illuminating even the darkest corners of the reef with up to 70 watts of power.
Copyright 1997, by Bishop
Museum. All rights reserved.
All media are for the personal
use of students, scholars and
the public. Any commercial use
or publication of them is strictly
  If you have any comments/suggestions about the documents on this Palau 'Twilight Zone' Expedition web site, send e-mail to Richard Pyle at deepreef@bishopmuseum.org

The State Museum of Natural and Cultural History
For Museum Information, call (808) 847-3511
Bishop Museum 1525 Bernice Street Honolulu Hawai`i 96817 USA

Revised on 12 July 2000