01.09.2008 Shore snorkel & night snorkel

Day Schedule: 7:00 Breakfast
8:30 – 10:30 Shore snorkel at the lighthouse
11:00 – 11:30 Debriefing of morning snorkel
11:30 – 12:00 Presentation of the individual projects
12:00 – 13:00 Lunch
13:00 – 18:00 Time for individual activities
18:00 – 19:00 Dinner
19:00 – 20:00 Discussion of individual projects
20:00 – 21:00 Night snorkel

Weather: fine, 22°C
Tides: High tide – 9:24; Low tide – 15:29

Details:
The task during the mornig snorkel was to utilise the knowledge aquired during the last two days to identify corals, fishes and invertebrates along the low energy reef flat and the reef slope. A second focus was on the reef topology, zonation and its geology and compare with the high energy side of the reef. We started snorkeling at the lighthouse in the southwest of Lady Elliot Island and worked in groups of two or three students. After the snorkel we discussed the impressions and identified the species encountered in the lecture room. Prof. Wörheide drew a cross section of Lady Elliot Island and its reef on the white board and explained the geology of the reef and its different zones in detail.
This sketch of the topography of Lady Elliot Island showed the difference between the high and the low energy reef. Todays shore snorkel was at the low energy reef. The different energy levels control the topography of the reef. In the low energy reef we find a high living coral cover and only little vacant space. The coral community here is dominated by table corals (Acropora sp.). At the reef crest we found a lot of coraline red algae. The reef flat is compressed in comparison to the exposed side of the reef. There we found more massive coral growth forms and many incrusting corals. During cyclones or heavy storms, the fragile corals will break off and are being washed on the reef crest, or transported to the lower end of the reef slope in deeper water. Frequently, we observed broken-off and upside-down lying table corals on the windward side of the reef. At this side of the reef there was a lot of uncovered space in between the corals. At the windward exposed side of the reef we could observe typical spur-and-groove systems, radially running channels that break up the fore-reef and transport debris and backflushing water. In these channels, large coral-rock fragments, covered by algae, were found. Such spur-and-goove systems were not observed at the sheltered side of the reef. The coral reef actively grows and expends at the reef crest.
At the high energy reef slope we found more nocturnal fishes. In contrast to that we find more schools and shools at the low energy reef. Identified species included:
Bennett's butterflyfish - Chaetodon bennetti, Bennett's Puffer - Canthiguster bennetti, Bigeye Trevally –Caranx sexfasciatus, Bird wrasse - Compnosus varius, Black-banded snapper – Lutjanus semichinches, Black-beach - Anampses neoguinaicus, Black-tailed Dascyllus – Dascyllus melanosus, Blackspot Tuskfish – Chaerodon schoenleinii, Blue blanquillo - Malacanthus lathorittanes, Blue devil fish – Assessor macneilli, Blue spotted rockcod – Cephalopholis cyanostigma, Blue tilefish – Hoplolatilus starcki, Blue-green chromis – Chromis viridis, Bluestripe seaperch – Lutjanus kasmira, Checkboard wrasse – Habichoeres hortulatus, Cleaner wrasse - Labroides dimiditus, Clown coris - Coris aggula, Clown triggerfish – Balistoides conspicillum, Common cleaner wresse – Labroides chimidotus, Cook’s cardinal fish – Apogon cookii, Double seddle butterflyfish – Chartodon ubietretus, Dusky butterflyfish – Chaetodon flavirostris, Fiveband flagtail – Kuhlid mugil, Giant grouper – Epinephelus lanceolatus, Giant sweetlips – Plectorhinchus alboviltatus, Goldstriped sweetlips – Plectorhinchus chrysotaenia, Green moon wresse – Thalassoma lutescens, Hawaiian Triggerfish - Rhinecanthus aculeates, Lined surgeon - Acanthunes lineanes, Longfin Batfish - Platax teira, Manta ray - Manta birostris, Manybar goatfish - Parnpeneus multifasciatus, Mashed bannerfish - Heniochus meneceras, Midnight dottyback – Pseudochromis paranox, Neon demsel – Pomocentrus coelestris, Orange-banded coralfish – Coradion chrysozomus, Oval spot butterflyfish – Chaetodon speculum, Peacock grouper – Cephalopholus argus, Reef lizardfish - Synodus varieganes, Reef needlefish – Strongylura holidayensis, Riversnapper – Lutjanus argentimaculatus, Roundface – Platax tiere, Royal dottyback – Pseudochromis paccuguellae, Scissortail sergant – Abudefduf sexfascitus, Six-spine leatherjacket – Meuschenia freycineti, Slender suckerfish – Echeneis naucrates, Spot-tail butterflyfish – Chaetodon anellicandus, Spotted unicornfish – Naso brevirostres, Sunset wrasse - Thalassoma lutescens, Teardrop butterflyfish - Chaetodon unimachlanus, Threatfin butterflyfish – Chaetodon auriga, Trumpet fish – Aulostomus chinensis, Waite’s splitfin – Luzonichthys waitei, Yellow-lined coris - Coris aurilineata
In the evening we went night snorkeling. We met at 20:00 at the resort and snorkeled on the reef flat. We saw nocturnal animals like the blue spotted stingray and the Epaulette Shark – Hemiscyllium ocellatum.