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Rossel Island Lagoon, Dive Log, PNG

April 2006



Date: April 15th TI: 1330 TO: 1415 Max Depth: 37m
Divers: Paul, Michel, Katie, Rebecca, Sharman
Date: April 15th TI: 1500 TO: 1550 Max Depth: 35m
Divers: Eibes, Becky, Orla, Sylvie, Heather

The perimeter of this platform reef is an extremely steep wall around which turtles, sharks and other pelagic fish roam. Acropora and Porites were the dominant coral genera, although hard coral diversity was quite high in some places. Overall the corals appeared healthy but a few notable conditions were observed. The divers noticed fish predation on the corals such as bite marks and scratches. Bleaching was observed on Pachyseris at about 10-13 meters depth, and white band disease was observed on a small table Acropora at about 15 meters depth.

On the second dive, a 15 foot-tall pillar was encountered. It is assumed that it was part of a post for a reef marker. It was almost square but the edges had eroded and now had soft coral overgrowth. 

The fish life on this reef was incredible. Large schools of rainbow runner (~50), trevally (~150), big-eye tuna (~30), and bumphead parrotfish (~25) swam by the divers. Napoleon wrasses were observed on this reef. Apart from the many small reef fish, a huge potato cod was sighted. White-tip, black-tip and grey reef sharks were all present on this reef as well.

A hawksbill sea turtle was observed on each of the dives. The turtle sighted on the first dive was about 50 cm carapace length.

Eight giant clams reside on this reef. One of them was a meter long while the others were between 20-50 cm. Only one sea cucumber was sighted on this reef, while no green snails, trochus snails, or crown of thorns were observed. Other invert observations include many diadem sea urchins, a few nudibranchs, and a high diversity of soft corals, barrel sponges, tunicates, hydroids and crinoids.

The visibility was quite good, about 30 m, and there was an outgoing tide of about 1.5 knots.

 

B)S 11°20.73' E 153°39.35' Reef east of Bommies
Date: April 16th TI: 0940 TO: 1030 Max Depth: 30m
Divers: Eibes, Sharman, Becky, Kitty, Carol
Date: April 16th TI: 1245 TO: 1320 Max Depth: 25m
Divers: Michel, Sharman, Katie, Rebecca, Sylvie

This reef is also a platform reef surrounded by a steep wall. There was not a high live hard coral coverage on this site. Less than 5% of the wall contained live hard coral, which seemed to grow in patches rather than evenly across the wall. On the shallow portion of the wall Porites was the dominant coral genus, while Montipora was the most abundant genus on the deeper section of the wall. There were also many small Tubastrea colonies on the wall between 20-30 meters depth. Bleaching was observed on Pachyseris at about 12 meters depth, and white band disease was observed on an Acropora colony. Sea fans and a diverse array of soft corals covered the wall, along with a high concentration of Halimeda algae.

Many sharks were seen at this site. On the first dive 10-15 sharks were sighted, while on the second two small white-tip reef sharks and one small grey reef shark were seen. Large schools of fish were also present including a school of about 20 huge dog tooth tuna, and 30 large bump head parrotfish. Throughout one dive about eight Napoleon wrasse were sighted. Other interesting fish encounters included a manta ray and two large moray eels. Additionally, two hawksbill turtles were seen on this reef.

  Between the two dives, 12 sea cucumbers were observed, most of which were low-value species. Three giant clams were sighted; one was about 20 cm in length while the other two were about 30 cm in length. Oysters were abundant, attached to the steep coral wall.

The visibility was good, and there was a slight current running out of the lagoon.  

 

C) S 11°20.30' E 153°38.80' Outer Bommie                     
Date: April 16th TI: 1100 TO: 1200 Max Depth: 34m
Divers: Paul, Michel, Orla, Rebecca, Heather

This dive took place on the second bommie west of dive site B. The weather was rough which enabled us only one dive on this site. The live hard coral coverage was low and occurred in patches, but soft corals and oysters covered the wall. Many small reef fish were present along with a school of about 20 small barracuda on the sandy bottom adjacent to the reef. Two turtles were also sighted, one green and one hawksbill. Only two low value sea cucumbers and three giant clams were observed on this reef.  The divers enjoyed this reef.  


 

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