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Sept. 96 Aquarium Net An Aquaristic Tour Around the World

Alf Nilsen takes us on a tour of the reefs around the world. Sept. 1996 Aquarium Net, Aquarium Net has numerous articles written by the leading authors for the advanced aquarist

AN AQUARISTIC TOUR AROUND THE WORLD

Part 1

The Australian Queensland Coast and Near Shore Reefs

By Alf Jacob Nilsen, Norway Reprinted by permission of Das Aquarium

In the summer of 1991 four lucky guys got the opportunity to travel around the world, to study remote coral reefs, magnificent jungle and public aquaria. They got the opportunity to meet a lot of interesting aquarists and biologists, to see rare animals and to create memories for a life time. One of those guys was me; who could not have done it all if it was not for Erling, Thor Petter and Terje - my three good friends and travel mates. In this series I would like to share memorable aquaristic moments on this journey around the world with you.

The departure from Sola Airport outside Stavanger in Norway was set to 28. June -91, but the planning had been going on for more than 18 months. All the letters, the telephone calls and the use of the incredible telefax-machine that had taken hundreds of hours, all the struggle to make the money for the trip, all the "ifs" and "perhaps" were now history. This was the day, that the planes left for the Far East and further on to Cairns, Australia. We were on our way !

Ahead of us was a couple of days in Singapore to buy some photoequipment, a month in Australia to explore continental Islands, the exotic Queensland-towns of Townsville and Cairns, The Great Barrier Reef and the Coral Sea, explore the Great Barrier Reef Aquarium and a week in the bush to explore remote areas in Queensland's jungle and table-country. From Australia we would head for the exotic Fiji islands in the South Pacific and from there we would travel to Hawaii and meet with director Bruce Carlson at Waikiki Aquarium before taking a look at reefs and private reef-tanks in Florida. Many thoughts went to our brains as we tried to make time pass in what seemed to be endless hours in planes. Could it all work ?

Townsville - a city in the tropical sun on the Queenslandcoast build on the banks of Ross River and a portal to the Great Barrier Reef - were to be our home for the days before heading towards the Coral Sea. With its 120.000 inhabitants and absolutely glorious weather with as much as 300 sunny days a year, Townsville suited us perfectly and became a town "to fall in love with". Our accommodation was Central City Gardens Motel where we got our own flat, cooked our own meals and were free to do as we wanted. Located next to Mike Ball Dive Academy, Central City Gardens is the ideal place to stay for diving visitors in Townsville. From the impressive, 286 metres high granite mountain "Castle Hill", situated one gets a tremendous view of the town, and "Castle Hill" a landmark in the area.

Australian Coral Reefs

To marine aquarists Australia is mainly connected with "The Great Barrier Reef" stretching for more than 2000 km along the east coast of the country. The Great Barrier Reef is adiverse complex of reefs and very young as a reef system. The southernmost part of the reef-platform is not more than 2 million years old. Changing in sea level coursed by the melting of ice several times during this period, has formed platforms and reefs developing in different areas. For this reason we can find remains of ancient reefs on the Australian mainland, far from the present seashore as well as old reef in deeper waters. The reef-growth in Australia GBR to day is probably not more than 5-6000 years old. The reefs accessible from Australia can be divided into four major groups:

  • Fringing reefs that has developed along the coast, such as Alexandra Reef, or around continental islands, such as Magenetic Island outside Townsville.
  • Coral Cays which are coral island that have developed when the growth of corals has reached the surface. They are usually situated some distance from the shore, but a few can be found near the mainland such as Green Island outside Cairns.
  • The Barrier Reef situated far from the mainland (except in the far north) containing a complexity of reef systems such as the chain making up "The Ribbon Reefs"east of Cooktown.
  • Oceanic Reefs situated in the Coral Sea several hundreds kilometres from the mainland such as the huge Flinders Reef in the Coral Sea 250 km east of Townsville.

If one wants to travel the GBR one has to be aware of this grouping. The fringing reefs and some coral cays are relatively easy accessible, but also much visited by tourists. The quality of the reef is very variable and so is the visibility. The outer barrier reef can be reached by several organised boat operators of very variable quality, while the

Coral Sea is only accessible by a few expensive and high quality boats. We shall return to this in the following articles, but I must stress that a successful view of the Australia Coral reefs requires a lot of planning and is a rather expensive task if one wants to see high quality reefs. One should expect at least one year of planning prior to departure. For you information I have listed a series of useful addresses at the end of the article.

Near Shore Reefs

Fringing Reefs are best developed around continental Island especially in the area north of Macay. Very well known are "The Whitsunday Island". Fringing Reefs are very limited, developed in association with the Australian mainland because of the many rivers that bring huge amounts of fresh water to the shore. An exception is Alexandra Reef in Cape Tribulation National Park just south of Cooktown where the reef meet the rainforest. The Fringing Reefs can be as narrow as 20 metres where the rocky shore steep into the water, while they can be more than 500 metres wide in bays - also depending on the wind and runoff of fresh water. The reef flats of a fringing reefs are usually a bit disappointing compared to the luxury growth of corals we can find further out of the barrier reef. However, the mixture of algae and coral are to us aquarists very interesting and show that not all corals require clear waters and very nutrient poor environment, but can tolerate a shifting in the conditions. To tolerate an occasional adverse condition is a must both for animals and plants of the fringing reefs. Nevertheless can the fauna of a fringing Australian reef be diverse. Of 81 species in the five most common families of stony corals 79 has been found on fringing reefs. The most important difference is, however, the number of algae found on the near shore reefs, a number much higher both in species and biomass than on reefs further out.

Magnetic Island

Magnetic Island is a typical inshore continental island situated not more than 20 minutes ferry ride from Townsville Harbour. The name "Magnetic" is a good one. This island is so beautiful that it is almost magic and has a magnetic pull to visitors. 2/3 of the island is a National Park while the other third a used for residential and commercial development.

There is only one road on the island going from "Picnic Bay" in the southwest to "Horseshoe Bay" in the northeast. The best way to see the island is to rent a "moke" which is a small fourwheel car that carries two persons and luggage. The road passes a series of absolutely beautiful bays with shallow, peaceful beaches surrounded by interesting vegetation. It is strange to find mangrove vegetation next to pine forest, but this is only one of the many interesting things that make the Australian flora and fauna so unique. The rocks that surround the beautiful bays at Magnetic Island reminds us of our own coast. They are not calcareous rocks at all, but of volcanic origin.

We chose "Arthur Bay" as a base for the day, but soon got very disappointed when we found that the visibility in the water was less than one meter ! The beautiful reefs that we knew surrounded "Arthur Bay" were impossible to find. However, this is a risk with the continental islands that are situated close to mainland. The visibility varies a lot highly depending on the wind. In the European summer a relatively strong south-east wind is normal and coursed by a high pressure that build up south of Australia, and is in fact not at all the most ideal weather for diving on the inshore reefs.

As snorkelling was less interesting in the muddy waters we did search the shoreline and discovered a lot of algae-eating snails clinging to the rocks. The "rock oyster" Crassostera amasa (fig K1271) was very common and lived in hard layers on the shoreline rocks. The sun was strong and burned our northern bodies and we did measure the light intensity to app. 65.000 lux on the beach on midday. But no visible corals at "Arthur Bay".

So we moved to Horshoe Bay further east on the island. Herethe waveaction was much less as the bay lied sheltered for thestrong southeast winds. But the visibility was still less than 1 metre. Nevertheless, we found our first Australian corals on the beach among algae and, mud and detritus on about 2 metres of waters. Trachyphyllia geofferoyi, Goniastrea spp., Goniopora sp., Acropora spp., Fungia sp., Lobophyllia sp., Porites spp . and Euphyllia fimbriata were stony corals that grew together with algae from the genra Lobophora and Codium. Huge stands of soft-corals was also common. But what can you conclude when the visibility is less than 20 cm ! ?

So, if you want to study the Australia Inshore fringing reefs you must visit the area when the visibility is good which meant in the Australian summer, normally best from September to December.

Green Island

"Green Island" is situated northeast of Cairns, a town 4 hours drive north of Townsville. The island is a coral cay which means that it is built from the growth of corals and from sand and debris that have gathered on spots of the reef by winds and wave action. A young cay is nothing more than a sandbank on the reef (fig K1258). On the GBR there are around 200 such sandbanks. Birds settle on the sandbanks and leave guano which in turn builds up to a thin layer of humus. Halophytic plants (= plants that can tolerate salt) can utilize this tiny layer of humus and fastened on the sandbank. Their tiny roots are strong enough to increase the build up of humus and makes the soil's content of freshwater to increase. The speed of which a cay develop and the diversity of plant life is both highly depending on the amount of rain that falls. Eventually the sandbanks grow, the plant life develop and an older cay contains a lot of vegetation, animal life, seabirds and in our days sometimes many tourists. There are no huge mountains and rocks like on the continental islands, and the "Green Island" is indeed very different from Magnetic Island.

"Green Island" is reached by a fast going boat from the harbour of Cairns. As one approach the island itself is merely visible. Only a tiny bit of vegetation raises above the horizon. "Green Island" is a very typical tourist resort which is operated and owned by Japan ! The famous underwater observatory lies on the pier where the boat trip ends. To spend an hour in the observatory is worth time and money. Although the observatory itself is very small and rather old, it gives an idea, especially to those who do not dive, of what a coral reef looks like from below.

A visit on "Green island" requires a full day indeed. There are plenty of activities to take part in. One can relax on the beach and take a sunbathe here, but more exciting for aquarists are to join a "reef-walk" at low tide. You join a group of tourist guided by one of the island's staff and walks out on the reef-flat. As a biologist and aquarist I soon found the information from the guide a bit dull (although it was all very pleasant and correct), and soon took off of my own. And the reef-flat of "Green Island" is very interesting! The life here can stand as a textbook example of the general life of a shallow water reef flat. Near the shore beds of seagrass ( Thalassia spp .) grows and among it one find several species of sea-cucumbers and snails. A bit further out the diversity of algae increases and the first corals appear. The dominant species of coral is Porites cylindrica (fig. K1249) which was completely dried out during low tide. Many species in the family Faviidae ( Goniastrea spp., Favia spp., Favites spp . and others) were found and well and huge microatolls build from the various Porites sp. Radioactive measurements has shown that some of these microatolls are several thousand years old ! Among the corals and in very shallow water (less than 20 cm) were hundreds of blue starfish, Linkia laevigata and numbers of the beautiful Tridacniid mussle Hippopus hippopus . For an aquarist a full day can be spend on reef walk and hundreds of slides can be shot ! Do remember that it strictly forbidden to touch any animal and to remove anything from any reef in Australia !

It is also possible to dive on "Green Island". A diveboat bring you out to the housereef which lies only a couple of hundred yards from the beach. From my point of view the reef is also well seen by snorkelling. In an hour of skindiving I saw turtles, giant clams (Tridacna gigas), huge stands of the typical Australian soft-coral Sinularia flexuosus , huge growth of table-shaped Acropora hyacinthus and a wide variety of fish including the big lipfish Cheilinus undulatus. If one want to see the reef without getting wet a trip in the glass-bottom boat enabled you to watch the reef in this way. All in all, a day at "Green Island" can be an exciting and diverse aquaristic experience.

Low Island and Alexandra Reef

Low Island is another coral cay situated just outside Port Douglas north of Cairns. Unlike Green Island Low Island is not a tourist island. It contains, like many cays along the Great Barrier Reef, a lighthouse which acts as a landmark in the area. A famous mangrove swamp with the mangrove trees Rhizophora stylosa lies next to the cay and a huge, but not so diverse reef-flat surrounds the island. As one moves further up north the Queensland coast, the mangrove forest become numerous and occasionally we find untouched parts of the 60 million year old rainforest that is a relict from the forest of South-America way back when the continents were attached in the huge Pangea-continent. To visit this area one needs a four-wheel-drive jeep and a guide. To move into this area on you own is very foolish. The area is also only accessible in the Australian winter when the dry season is there. During the wet season everything is water and inaccessible.

Alexandra Bay is reached through a very small pathway through dense rainforest, and a walk from the "highway" through this pathway which after only a few minutes opens up on Alexandra Bay, is indeed a unforgettable event. This is where the rainforest meets the reef and must be one of the most beautiful places in the world. You stand with you back towards the rainforest and in front of you is a huge muddy beach sparsely covered with mangrove trees and which stretches until the very horizon. On the end of the beach is the reef, a typical muddy reef-flat covered with brown algae and a few corals. The area must be visited during low tide when it is possible to walk to the entire reef edge. On the way out in the open we discover worm-like castings (fig K1266) which are created by the holothurian Paracaudina chilensis which burrows 10-20 cm in the mud and which can be mistaken for a worm.

Millions of small sand-balls made by small crabs do also cover the whole beach. On the mangrove trees a lot of snails gathers and mangrove crabs runs all over the place. Further out "live rocks" are covered with brown algae and water glides in and out of small channels. If the rocks are turned a variety of organisms are found and the structure of live rocks are seen. The water is very muddy, but in this muddy environment we did find several stony corals both from the family Acroporidae and Faviidae. To stand on the edge of Alexandra Reef with the open ocean and the Great Barrier Reef in front and the Daintree Rainforest in the back is an eventthat must be experienced to be believed.

Next Month ... "The Great Barrier reef Aquarium in Townsville".

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Last modified 2006-11-19 01:38
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