Daily Log Report for
18 May 1997

Submitted by Richard Pyle

The weather was magnificent today; our last day of diving on this expedition. John left us early this morning for his return to Hawaii. The rest of us also started out relatively early this morning, cruising at high speeds over glassy water towards the south end of Palau. Shown in the photo at right are the "Seventy Islands" of Palau; a group of rock islands that are protected from human disturbance by strict conservation laws. We passed (at a distance) by these islands on our way from the marine lab facilities in Koror, to the island of Ngemelis, near the southern tip of Palau's main lagoon.

Our destination was a place known to divers as "Big Drop". This is a spectacular sheer vertical reef drop-off starting from the surface, and continuing down in places more than 1,000 feet. At the particular spot we chose to make our dive, the vertical wall bottoms-out at a depth of about 170 feet, then a sand and rubble slope continues down to well-past 300 feet. Ken was originally going to join us on this dive, but discovered a leak in his mouthpiece as he was getting in the water, so he decided not to go deep.

Pat and I descended together, then I saw some unusual fishes in a rubble patch at a depth of about 260-275 feet. I stopped and tried to collect some, while Pat continued further down the slope, along the face of a small rock "buttress" further down the slope. Among the fishes I collected was another female specimen of the angelfish, Genicanthus bellus. I also saw many individuals of the wrasse we are calling Cirrhilabrus sp. 1, but we have enough specimens of this new species already, so I didn't bother trying to collect any more of them.

During the ascent, I stopped to "decompress" the fish (as I have been doing on almost every dive this expedition). Unlike humans, who breathe compressed gas underwater, fishes (which breathe water) do not suffer from decompression sickness (the "bends") when brought directly to the surface from great depth. However, most reef fishes possess an organ called a "swimbladder", which is analogous to a scuba diver's buoyancy compensator device (BCD). Like the divers, these fishes expand or compress their swimbladders to maintain neutral buoyancy. However, if brought straight to the surface from great depth, the swimbladder will expand in response to the decreasing ambient pressure, in some cases crushing the other vital organs of the fish. To avoid this problem, I generally stop at some depth during my ascent and insert a hypodermic needle into the swimbladder, venting off the excess gas (see photo above). When performed properly by trained individuals, this procedure doesn't seem to harm the fish any more that a person is harmed when receiving a shot from a doctor. In most cases, the wound heals almost instantly, and if the fish is kept in clean water, does not develop any infections.

After venting the swimbladders of the fish I collected, I had an extremely enjoyable decompression along the spectacular "Big Drop" dive site. I was amazed by how closely I could approach the schools of fusiliers (fishes of the family Caesionidae - shown at right) with the rebreather. Bubble-producing scuba divers often have great difficulty getting close to these species underwater. I also saw an assortment of jacks (species of the family Carangidae) and a Napoleon wrasse (Cheilinus undulatus), among other reef fishes.

After a very pleasant lunch near Ngemelis island, we went to a spot called "German Channel" by the dive operators; a place just outside the "real" German Channel (a small boat channel dredged by the Germans) where manta rays often congregate. I was not terribly interested in manta rays, so I decided to sit the dive out, while Ken and Pat did a short dive with the rebreathers, and the others used what was left in the remaining scuba tanks.

Tomorrow we leave Palau early in the morning, which means we will be up late tonight packing gear. The expedition is now definitely coming to a close, and I feel confident at this point deeming it a complete success.

Dive Number 1 of 2
Divers: Richard Pyle, Pat Colin

Solid line indicates depth, dashes ("-") indicate
decompression ceilings, bar ("|") represents cleared to surface.
Max. Depth: 278 feet (85 meters) Time: 10:52 am Duration: 1 hr, 58 min
Location: Ngemelis Island; "Big Drop".
Marine Life: I saw an unusual Cirrhilabrus wrasse with a lanceolate tail, but was unable to collect it. I also saw, but did not collect, a species of basslet that appeared to be Pseudanthias hutomoi. I collected another female Genicanthus bellus (this one smaller than the previous one), as well as what we think is juvenile Cephalopholis sonnerati (but need to confirm). I also collected another specimen of the damselfish we have been calling Chromis sp. 2. I saw a group of what we are calling Cirrhilabrus sp. 1, but didn't bother to collect any more specimens.
Remarks: Ken was originally going to join us deep, but opted instead to stay shallow when his mouthpiece started leaking water at the beginning of the dive. The others (Lori, Lisa, Sara, and Jack) joined Pat and I on the decompression portion of the dive, as did Ken. It was a very pleasant decompression, swimming among the schools of fishes in shallow water.

Dive Number 2 of 2
Divers: Ken Corben, Pat Colin

Solid line indicates depth, dashes ("-") indicate
decompression ceilings, bar ("|") represents cleared to surface.
Max. Depth: 55 feet (17 meters) Time: 2:56 pm Duration: 52 min
Location: Ngemelis Island; just outside German Channel.
Marine Life: There were an assortment of surgeonfish of the genus Naso surrounding the boat, and nearby was a large school of Halfbeaks (Hemiramphidae). Although this area often has Manta rays, there were none seen by us.
Remarks: I decided not to dive this time, opting instead to stay in the boat. It was a very beautiful day, and I just wanted to relax a bit and enjoy my surroundings before departing tomorrow. The others reported a pleasant dive, except for a brisk current associated with the rising tide.

Disclaimer: Several aspects of the dive profile(s) illustrated above deviate from conventional wisdom regarding appropriate decompression procedures. The dives referred to on these web pages are of an experimental nature, and all persons involved with these dives are fully cognizant of the associated risks. The decompression practices followed on these dives are derived from published information, in conjunction with the many years of extensive experience of the divers involved. These practices have not been tested under controlled conditions, and may not work equally well for all divers. Kids, don't try this at home!!

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