Travel Stories

The Indonesian Throughflow

Published

11 years ago

November 17, 2013

As you head out from the shores of east Bali on your morning dive you are surrounded by a host of tiny outrigger fishing boats, their sails flashing in the sunlight as they dance over the waves. It is a unique, entrancing and inspiring sight, all the more so because this is a very special place.

These fishermen (and you in your dive boat) are scudding over waters that lie on the cusp of geological and biological change. In the past, at times of low sea levels, this coastline marked the very tip of a massive Eurasian Continent. During those periods you could have walked all the way from Bali to Paris without getting your feet wet. However, even when the world’s oceans were at their lowest ebb, you could never have gone any further east without harnessing wind or mechanical power, due to the depth of the chasm between Bali and Lombok, the next island in the chain.

A Fisherman contemplates the ocean

A juvenile lion fish finds sanctuary in the mouth of a bottle placed in the sand in Amed East Bali

Wallace’s Genius

In the 19^th century the great naturalist Alfred Russel Wallace spent time in the islands of what is now Indonesia and remarked on how different the species of bird and animal living in the west of the archipelago were from those that inhabited the east. His findings led him to draw a line on a chart that ran through the Makassar Straits between Borneo and Sulawesi, crossed the Banda Sea and continued down through the straits between Bali and Lombok. To the west of the line, in Bali, Borneo and beyond, animal and bird life was predominantly Asian. On the other side of the line, in Lombok, Sulawesi and further east, the animals and birds were strikingly different, mainly species that originated in or resembled those found in New Guinea or Australia. Brilliantly, he deduced that the reason was geological rather than biological: “I believe the western part to be a separated portion of continental Asia, the eastern the fragmentary prolongation of a former Pacific continent.” Of course, we now know that he was absolutely right!

During his trip Wallace also came up with the notion that natural selection was the driving force behind evolution. At the same time Charles Darwin was on the Beagle sailing the seas on the other side of the Pacific and drawing similar conclusions. But that is an entirely different story.

A Very, Very Big River

What Wallace could not know, in fact something that no-one noted until almost 100 years later, was that one of the factors preventing species crossing Wallace’s Line was an enormous moving body of water. The fossil and historical records show that elephants, orang-utans, bears, tigers and other Asian mammals never managed to bridge the gap. They got as far as Borneo and Bali but no further. Even those animals that tried to swim over or were caught on driftwood after a flood could never make the crossing as everything that enters the water on one side of the line is swept away far from land long before it can reach the other side.

In the Pacific Ocean to the northeast of the Indonesian archipelago, the sea level is about 20 centimetres above average. In the Indian Ocean south of Indonesia the sea level is 10 centimetres below average. This 30-centimetre drop between the oceans creates water movement on a massive scale, a phenomenon variously known as the Indonesian Throughflow or Pacific – Indian Throughflow. The most direct path between the oceans and the path taken by a large portion of the Throughflow, as you may have guessed, runs right along the Wallace Line between Borneo and Sulawesi then down through the straits between Bali and Lombok.

Visualise it as a very, very big river pouring through a canyon between continents. How big? Ocean current flows are measured in units called Sverdrups with one Sverdrup being 1 million cubic metres of water per second moving past a given point. The flow of the Amazon is about half a Sverdrup and the combined flow of all the rivers in the world is about one Sverdrup. The flow of the section of the Indonesian Throughflow that courses past the eastern tip of Bali is estimated to be 2.6 Sverdrups, that is, two and a half times the total of all the rivers of the world put together!

Mola-mola and Diver

Creatures Great and Small

Thus, a vast amount of water is drawn from the Pacific Ocean and sweeps through tropical seas, across the equator and past the islands of northern Indonesia. As it travels, it picks up and carries along with it an enormous quantity of marine larvae, eggs and juveniles and deposits them wherever it encounters land. It is no surprise that most of the legendary Indonesian scuba diving destinations lie along the route taken by the Throughflow. For example, the calm bays of black volcanic sand in northeast Bali are astonishingly rich in rare species. Enterprising dive operators need only sink a stripped motor bike frame or a dozen broken bottles set in a block of concrete and they soon become a collecting point for small fry seeking sanctuary. These tiny fish attract predators such as frogfish, lionfish, scorpion fish, eels and other rare and fascinating creatures and they in turn attract scuba divers and snorkelers.

Dive guides who work in the area often report larger sightings too, such as dugongs and a host of cetaceans, including killer whales. There are sightings of bizarre and highly unusual marine life. Last year an amateur diver captured video of a long entirely transparent eel; the film became a Youtube sensation.

A Plan of the Throughflow

Diving the Throughflow

Beyond the calm water in the bays, the Throughflow provides dramatic drift diving along unusual seascapes. Towering barrel sponges lean at 45 degrees as if in the presence of a powerful wind and, in places, pinnacles and walls are scoured of their usual natural coating. But in the valleys and other places where the topography provides a little shelter from the onslaught of the current, the enormous profusion of corals and fish life can take your breath away. In one bay, for example, just a few metres off shore from the lines of colourful fishing boats that decorate the beach, you can find hectares upon hectares of multi-coloured staghorn coral, as glorious a sight as any of Bali’s rice field terraces. Drifting over these fields of pointed sculpture in pastel shades, populated by clouds of damselfish which rise and fall as you pass is a true magic carpet ride.

Mola-mola in sun

Cool Animals in Cool Water

The Throughflow passes by the southeast coast of Bali too and close to the village of Candidasa a series of small islands, some not much more than jagged shards, are home to some of Bali’s fishiest diving. Schools of jacks, rainbow runners and barracuda use the dramatic rock formations for shelter from the current and reef sharks circle around watching for weakness and waiting to strike.

Further south, attempting to block the southern end of the Lombok Straits like an ill-fitting plug is Nusa Penida, the exposed part of an undersea ridge that connects Bali with Lombok. The Throughflow races by on both sides of this island, offering healthy coral, lots of big animal sightings and exhilarating drifts. Sometimes, however, the ride can be a little too wild and conditions can change rapidly and vary dramatically. One day you will drop in on a site and be entertained by a dozen manta rays, which sweep in from the deep to feed on plankton in calm, bottle green water. On another day, the same site will be empty of fish and the ocean will merely throw you around in a soup of spume and spit you out into the southern ocean on a fast train ride to the horizon.

Current pools created by the Throughflow off the coast of the village of Aas on the very tip of Asia

Seasons have an effect on the speed of the Throughflow, with August usually the strongest month when the southeast monsoon is at its zenith. This also coincides with mola-mola season around Nusa Penida. The arrival of these bizarre creatures may be linked to the increased strength of the current but this time of year also sees an upwelling of colder water in the south of the Lombok Straits and that may be significant too. The reliability of mola-mola sightings during this period has created a small boom in the local diving industry. Be warned if you are thinking of joining the crowds: water temperatures can drop to the high teens centigrade but when you are face to face with an oceanic sunfish measuring four metres from tip to tail you will probably not even notice!

Blogs

Gozo: An Underwater Treasure Trove in the Heart of the Mediterranean

Published

3 weeks ago

August 13, 2024

Team Scubaverse

The Maltese island of Gozo lies at the heart of the Mediterranean and, despite its diminutive size, it punches well above its weight as a world-class diving destination. So, what is it that’s so magical about Gozo and the surrounding sea that, like the bioluminescent light of an angler fish, draws in divers from far and wide?

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

Standing on the bastions of the UNESCO-rated medieval citadel at the centre of this tiny tranquil idyll, you can see nearly 50km of enticing curvaceous coastline circumscribing this golden island. Crystal-clear waters lap at Gozo’s shore which boasts a wealth of dive sites in every direction – the colours shift smoothly from a transparent jade over white sand to a rich sapphire blue over the deeps beyond, and all promise spectacular visibility. Raise your eyes from the warm azure water, and you’ll spot Gozo’s sister Comino, a short boat ride away, with yet more underwater wonders.

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

It’s no wonder that the ancient Greek myths tell of how, when Odysseus came here, he stayed for seven years. You might hear tell that he was captivated by the sea-nymph Calypso but we know better: surely it was the lure of the sea and the beauty beneath the surface that kept him entranced!

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

Zoom in to Xlendi, the island’s most picturesque fishing village, acclaimed for its scenic bay: it’s a charming cove nestled between dramatic cliffs. Here, just steps away from the water’s edge, you’ll find Gozo Dive (formerly St Andrews), a dynamic, professional dive centre which caters comprehensively for every level of diver, from the exuberant 8-year old or the nervous beginner to the avid advanced open water diver and established experts with bulging log-books under their weight-belts.

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

Xlendi Bay itself is a marvel – whether for a shake-out dive on its gently sloping sands, or for something more dramatic. Underwater, it’s spectacular, with inner and outer reefs, a towering pinnacle, a secret tunnel into an open water cave, and the criss-crossed ropes of the boats on one side of the bay that add a ‘Pirates of the Caribbean’ flavour for those with a whimsical leaning.

Xlendi’s deeper waters are also home to the world’s first deepwater archaeological park where a Phoenician shipwreck dating back to the 7th century BC lies 110 metres below the surface. Although some intrepid divers head down to see this for real, most people view this wreck and its ancient amphora on screen inside the historic watchtower that stands on guard at the entrance to the bay. (Standing above Roman salt pans, traditionally used to harvest sea salt, this tower dates back to the Knights of Malta for whom it provided protection against pirates, deterring smugglers and quarantine evaders. It was also used as an observation deck during World War II, when the entire Maltese Islands were awarded The George Cross for bravery by King George VI.)

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

With a 30-year history of excellence, and a friendly international team of professional instructors, Gozo Dive offers guided diving for everyone, all year round, whatever your ambition whether that’s simply a 1 day try dive you’re after, Advanced Open Water Diver, Rescue Diver or specialty courses. Training packages available include PADI, SSI, RAID & SDI/TDI for adults and children, and technical, CCR & instructor courses too, all personalised as you wish. Fancy developing your underwater photography or learning Trimix techniques to explore deeper dive sites with the use of helium-based breathing mixtures? Rebreather courses or looking to build up 30 or more rebreather hours before your MOD2? No problem. With a dedicated Tech Room, Gozo Dive have it all covered.

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

Gozo Dive will welcome you – in English, French, Italian, German, Spanish or Maltese – as a solo diver, a family or a large group, and with the brand-new deluxe Gozo Dive Residence on the hillside just above Gozo Dive, they’ll can make life easy for you with a fully organized dive & stay package (complete with airport transfers). Designed for divers, these brand-new self-catering apartments have stunning bay-view balconies, a breathtaking roof-top plunge pool, air conditioning and powerful WiFi.

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

Beyond Xlendi, North, South, East and West, Gozo is a playground of caves, tunnels, reefs, and wrecks whatever the direction of the waves and wind. Most dives are accessible from the shore; others, Gozo Dive reaches with its own purpose-built spacious boat. Stay in the shade, as you whip across the waves!

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

The Blue Hole is the most famous dive site on Gozo, an extraordinary rock chimney with a giant window to the ocean sixteen metres below the surface, from which you can venture out into Gozo’s Coral Gardens and Coral Cave or over a seabed scattered with giant boulders and geological intrigue. Just 100 metres away, The Inland Sea is another extraordinary spot, a green-blue lake surrounded by rock, from which you can follow a shallow tunnel to the cerulean blue beyond. For Game of Thrones fans, this rocky outcrop, ‘Dwejra’, is the location at which the wedding between the Dothraki warlord Khal Drogo and Khaleesi Daenerys Targaryen, was filmed. (You could also, on your final afternoon before you fly home, visit Malta’s ancient city of Medina, to see the Entrance Gate and streets, and squares of King’s Landing.)

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

Perhaps lesser known, but equally striking, on Gozo’s Northern coast, Cathedral Cave is reached by following an ‘underwater stairway’ of momentous boulders that leads into a large cave, to enjoy both above and below the water. Into this vast dome of rock, light floods from below whilst fresh air reaches you through a crack in the rock and the water’s a vivid blue. Surfacing here is a fantastical experience and an amazing photo opportunity.

There’s nothing like a wreck emerging from the seabed to trigger the imagination: at the MV Karwela, a 1950s passenger ferry from Valletta’s Grand Harbour sitting upright on the sand to the south of the island, the light dapples through the windows and wooded slats. Its classic split stairway evokes thoughts of the Titanic!

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

Then over on the remote island of Comino, the P31 is a decommissioned military patrol boat, scuttled at 21m for divers of all levels. It’s home to many fish and other marine life; and Gozo Dive guides will lead you through the interconnecting Santa Marija Caves with its slashed-rock Z-for-Zorro swim through. And that’s just for starters.

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

If you’re dreaming of a trip to Gozo but some of the family prefer to stay on the surface, snorkelling is an option at many of the dive sites. Alternatively, in Xlendi, there’s a small sandy beach and two swimming areas with lifeguards for splashing and diving. You can hire pedalos and stand-up paddle boards, and it’s a great starting point for coastal walks. Even the smallest legs can follow the secret path to Karolina’s Cave, a hidden sea cave used by nuns to access the sea in privacy. Oh, and Xlendi has the best ice-cream in Malta!

Email: info@gozodive.com / Tel: +35621551301 / Web: www.gozodive.com

(And should you – however unlikely it seems – decide to put your fins to one side for an afternoon, reliable regular buses deliver you to Victoria, the island’s main town, in less than ten minutes. Or because this gemstone of an island is only pocket-sized, Uber and the local equivalents, can transport you wherever you want to go in mere moments!)

Take the plunge and book your Gozo adventure, for this year or next, today!

Contact Gozo Dive Now:

Email: info@gozodive.com

Tel: +35621551301

Web: www.gozodive.com

Blogs

Alonissos: The complete diving destination (Part 1)

Published

1 month ago

July 22, 2024

CJ and Mike

In June we were incredibly fortunate to be invited to dive in Alonissos, a small Greek Island in the Sporades island chain located in the North Aegean Sea. While I have long been a big fan of the Greek Islands as a great holiday destination, I had not had the opportunity to do any diving on previous visits and Mike and I were extremely excited to see what Alonissos had to offer both above and below the surface!

The Sporades are easily accessible via the airport in Skiathos (the first island in the chain), which is served by Jet2 flights from all major UK airports from May through October. Numerous ferries and charter boats make island hopping from Skiathos Town a breeze. After an hour boat ride, the picturesque port of Patitiri was a wonderful introduction to Alonissos, where we were met by our gracious hosts Kostas of Albedo Travel and Dias of Alonissos Triton Dive Center. Mike and I were delighted to be staying at the Paradise Hotel, aptly named for its stunning views over the sea and great location for walking to the waterfront.

Alonissos is beautifully situated in the National Marine Park of Alonissos and the Northern Sporades, the largest marine protected area in Europe. The surrounding seas offer fabulous marine life, including incredibly rare species such as the Mediterranean monk seal. They boast deep walls covered in gorgonians and sponges, stunning topography with caverns, swimthroughs and pinnacles, and the first accessible ancient shipwreck from 500BC!

In locations where historical sites have been reported, the waters are largely restricted, but with collaboration between government, underwater archeologists and dive centres, incredible underwater museums are being created for a truly unique diving experience. Alonissos is home to the first of these, the Ancient Shipwreck of Peristera Accessible Underwater Archeological Site. The chance to dive into history (along with reports of healthy reef life and amazing underwater topography) meant Mike and I were keen to get in the water.

Our introduction to the diving around Alonissos was at the Agios Georgios Pinnacles, in the channel between Alonissos and Skopelos. This fantastic site was named “The Chimney,’ and proved to have a huge amount to see. We got to a decent depth here (over 25m), and marvelled at a colourful reef wall with a wonderful swim through whose rocky walls were absolutely covered with life. As well as brilliant topography there was no shortage of macro life here. We saw numerous nudibranchs, five different species in total. The second dive at Mourtias reef nearby was a shallower dive along a nice wall with lots of crevices. Several moray eels and grouper called this site home. We enjoyed looking in the crevices for lobster and smaller benthic life, such as cup corals and tunicates.

Our itinerary allowed us two dives a day with afternoons left to explore the island with our hire car and evenings to enjoy the famous Greek hospitality. This proved to be a lovely mix of in-water and land based diversions.

The next days diving to the Gorgonian Gardens and Triton’s Cave was to be even better! These two stunning sites are nothing short of fabulous. The Gorgonian Gardens was a deep wall near to the Agios Georgios islands. The ever-present currents in this deep channel meant that the sea life was amazing … the namesake Gorgonian sea fans dotted the wall at a depth of 30 to 50 meters, getting ever larger the deeper we went. Above 30m was by no means less beautiful, with sponges, corals, scorpionfish, moray eels and some rare and colourful nudibranchs.

The second shallower dive of the day was to Triton’s Cave or the Cavern of Skopelos, on the east side of that island. The spectacular rock formations had wild striations both above and below the water making a truly epic topography. The cavern entrance was at 14m, and big enough for a buddy pair, winding up to 6m and passing two beautiful windows out into the blue. Emerging from the cavern, the light at the shallower depths and the incredible rock formations made for a fantastic gentle swimming safety stop and we all surfaced by the boat with massive grins.