Scientific research topics 2000

1.) GROWTH OF HERMATYPIC CORALS IV: A LONG-TERM SURVEY
Ruth Zöhrer, Bettina Riedel, Niels Heindl

Abstract
This project presents the results of the annual growth of reef-building corals at the Royal Diving Centre (RDC) in the Gulf of Aqaba, Red Sea, Jordan. The survey was initiated in November 1997 and first results were obtained in November 1998. In 1999 and 2000 the most conspicuous growth was recorded in branching colonies such as Acropora sp., Stylophora pistillata, and Millepora dichotoma, like the growth of 74.1% in height of one S. pistillata. The investigation of growth and colonisation of corals on artificial substrates was extended in 1999 and yielded further results, such as the striking growth of 894% in height, 305% and 219% in two measured diameters of one Acropora sp. on a metal barrel, and 133% in diameter of one S. pistillata on a concrete block.

2.) ASSESSMENT OF CORAL REEF DAMAGE IN AQABA, JORDAN (2000)
Ines Lemberger, Pierre Madl, Bernhard Majer, Nicole Mandl, Andreas Rötzer

Abstract
This years course focused on three main topics. At first it was tried to evaluatethe Diver Carrying Capacity at the dives sites in front of the Royal Diving Center (RDC) according to an index based key (Coral Damage Index). This index revealed that divers in the first 10m and snorkelers in the first 4m do contribute to a certain degree to the deterioration of that contour reef, thus greatly reducing the yearly allowance of dives per year. The second topic aimed at a continuation of last years survey, where we revisited marked diseased corals sites and tried to document the spread of Coral Diseases by adding new sites for future monitoring. The third focus of our survey involved the application of an abbreviated version of the Revised Rapid Assessment Protocol. It confirmed the poor state of health of this reef section as the low coral coverage seem to indicate a fragile balance between calcium-carbonate substrate build-up and destruction.

3.) SHRIMP ASSOCIATED GOBIES IN THE NORTHERN RED SEA (AQABA, JORDAN)
Altmann Dominik, Unger Christoph, Traxler Elisabeth, Schober Eva, Herler Jürgen

Abstract
During the reef field course in Aqaba, Jordan, in 2000, the mutualism between gobiids and their associated shrimps was observed. The investigation area was located off the Royal Diving Centre in Aqaba. 7 different species of gobiids were found (Ctenogobiops maculosus, Ctenogobiops feroculus, Cryptocentrus sp., Amblyeleotris steinitzi, Amblyeleotris sungami, Lotilia graciliosa and Vanderhorstia delagoae). The observations were focused only on the latter 4 species. 5 gobiids and 1 alpheid shrimp (Alpheus djeddensis) were caugth for identification, especially to differentiate A. sungami from A. steinitzi, which look very similar in the field. Additionally, sediment grain sizes, fish abundance and distribution as well as the displacement of the burrow entrances during the night were recorded.

4.) SAND BOTTOM FAUNA IN THE GULF OF AQABA (RED SEA, JORDAN)
Grill Nadja, Jegel Elisabeth, Minarz Edith, Waitzbauer Wolfgang

Introduction
The infauna generally consists of: macrofauna (> 0.5mm), meiofauna (0.5 - 0.062mm) and microfauna (< 0.062mm). For technical reasons, we only worked with the macrofauna, which consisted of detritus feeders (Mollusca, Echinoidea) and predators (Gastropoda, Ophiuroidea, Crustacea and Polychaeta). The ashore habitat is characterized by unstable parameters like turbulence, salinity, temperature and the quality of the substrate, requiring special adaptations by the fauna.
For the first time, additionally to the front-mentioned investigations, the life tracks of different members of the infauna on the surface of the substratum have been registered and presented graphically.