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TWILIGHT EXPEDITION: COELACANTH

Herpolitha_limax_anomaly_Twilight_Expedition

It is not every day that you come face to face with a dinosaur dating back 400 million years, but for the fishermen in Kigombe on Tanzania’s northern coast it has become almost routine. In the middle of Kigombe, a village of simple huts on this breathtaking edge of the Indian Ocean, a young fisherman stood proudly before a large green plastic container. Ceremoniously he reached inside and hauled out a monster of a fish, slapping its 60kg (132lb) of flesh on a table, where three children gawped at its almost human-like ‘feet’. This is a living fossil, a fish with limbs, a creature once believed extinct: a coelacanth. Now it seems that man may have discovered the fish just to eradicate it, as ever deeper trawling throws up serious fears for the already dwindling populations of the fish, which lives at depths of between 100 and 300 metres (328ft to 984ft).

The appearance of these creatures off the Tanzanian coast is a dramatic and as yet unfinished chapter in the extraordinary story of the coelacanth, an ancient fish that was ‘rediscovered’. The coelacanth evolved 400 million years ago – by contrast Homo sapiens has been around for less than 200,000 years – and was believed to have gone the way of the dinosaurs until one was caught off the coast of South Africa in 1938.

The fish has a remarkable physiology – it has no backbone, but an oil-filled ‘notochord’ and four limb-like appendages, with stubby fins. It has a double tail and gives birth to as many as 26 young at one time. It is believed to gestate for 14 months and may live for more than 80 years. The young develop inside the mother, attached to the outside of a huge yolk-filled egg of about 100mm (3.9in) in diameter. 

The world waited another 14 years before the second coelacanth was ‘discovered’ in the Comoros, off the East African coast. Then several more were found and it was photographed for the first time in its natural habitat. But it is the appearance of the coelacanth off Tanzania that has raised real worries about its future.

It was in August 2004 that the local fisheries authority first received a phone call saying fishermen in Kigombe had caught a ‘strange’ fish. Officials went to check and to their amazement found two specimens of Latimira chalumnae – the coelacanth. Over the next five months 19 more were netted – weighing between 25kg and 80kg. Another appeared last January, then there was a gap until the fish again turned up as The Observer visited.

The numbers are perplexing officials of the Tanga Coastal Zone Conservation and Development Programme, which has a long-term strategy for protecting the species, with the help of Irish aid. They see a connection with trawling – especially by big Japanese vessels – near the coelacanth’s habitat, as within a couple of days of trawlers casting their nets coelacanths have turned up in shallow-water nets intended for sharks.

Hassan Kolombo, a programme co-ordinator, said. ‘Once we do not have trawlers, we don’t get the coelacanths, it’s as simple as that.’ His colleague, Solomon Makoloweka, said they had been pressuring the Tanzanian government to limit trawlers’ activities. He said: ‘I suppose we should be grateful to these trawlers, because they have revealed this amazing and unique fish population. but we are concerned they could destroy these precious things. We want the government to limit their activity and to help fund a proper research programme so that we can learn more about the coelacanths and protect them.’

Such is the paucity of resources for the programme that when The Observer visited its offices, we were shown an incredible specimen weighing 110kg – stuffed inside the office freezer. We had been asked to collect it.

As the locals helped to haul the monster into the back of a taxi, the village leaders wondered if the fish could help them attract tourists to their impoverished community. Yet one of the challenges may be to persuade the wider Tanzanian population that this is a species worth preserving.

Making our way to Tanga, with the coelacanth in the boot, Simon, The Observer’s driver from Dar es Salaam, was deeply unimpressed with his unexpected passenger. He produced a pink bottle of rose poppy perfume and sprayed it liberally around the car to mask the odour seeping in.

‘Why should they save this fish?’ he demanded. ‘This is not a good fish. It’s oily and you cannot eat this, and it’s a smelly fish.’ Fixing me with a puzzled look, he concluded: ‘It’s a bad fish.’

The ANDI Twilight Zone Expedition 2004

In May 2004 a team of ANDI’s top (American Nitrox Divers International, Ltd.) divers traveled to Indonesia to explore the depths between 125 and 150 meters on the slope of Manado Tua Island (North Sulawesi).

The team was hosted by Murex Dive Resort & Liveaboard who provided accommodations, boats and support staff for the expedition. In addition, Murex offered the best-equipped gas blending station in the area which is a necessary part of an expedition such as this

The expedition was led by Bart De Gols, Director of ANDI Benelux and completed 14 team dives to depths of 100 – 150 metres using Closed Circuit Rebreather systems and housed underwater video cameras. This team included one of the pioneers of mixed gas technical diving, Ed Betts, Founder and Executive Director of ANDI International.

These dives took place on the fringing walls on the south side of Manado Tua Island. This is where several local fishermen have caught Coelacanth fish (Latimeria menadoensis).

Bart de Gols & Ed Betts

Dr. Mark Erdmann, the project’s marine biology advisor had previously conducted one survey of the site from a manned submersible and believes that this twilight zone habitat is very suitable for coelacanths.

The ANDI team explored a large range of sites within Bunaken Marine National Park and recorded extensive video footage of the most interesting and unusual fishes and invertebrates encountered. The ANDI team also mapped those areas of the twilight zone in BMNP that are most amenable to further exploration and development as deep technical dive sites.

These dives where the first dives ever to explore the twilight region below 75 metres in Bunaken Marine National Park. Several divers have dived below 75 metres breathing air and upon resurfacing, remembered little or nothing of what they saw. Also Ed Baktis, Deep Support Diver on this expedition made the first rebreather dive in the National Park. The ANDI team used their own proprietary software to plan, calculate and log these dives in the 500 fsw range. This cutting-edge software is now commercially available under the trade name ANDI-GAP DivePlanner. This impressive dive planning tool is of benefit to recreational as well as technical divers. A trial version of this tool is available at …

ANDI-GAP DivePlanner

Until recently, the twilight zone has only been accessible to submersibles and commercial divers. Even then, submersibles have generally concentrated on the deep oceans, while commercial divers have rarely, if ever, found themselves diving in the vicinity of rich tropical coral reefs. There has thus been very little exploration and documentation of this unique habitat to date. In recent years, partly due to ANDI’s pioneering efforts, advances in SCUBA diving equipment, knowledge and techniques have greatly reduced the cost and risk of mixed-gas technical diving. This trend is certain to continue into the future.

Most technical diving at depths greater than 50 metres has been on deep wrecks, in cave systems, or simply aimed at pushing the depth envelope. Often deep dives are performed to test the limits of human physiology. There has been very little, if any technical diving performed whose primary aim is to explore and document the marine environment in the twilight zone. No exploration diving has ever been recorded in the golden triangle of marine bio-diversity centred on the Sulu-Sulawesi Seas (referred to as the Golden Twilight Zone) except the 2004 ANDI Expedition. This international “Twilight Zone” expedition led by ANDI Benelux is the first deep technical diving expedition in the world to explore and document this marine environment. It is thanks to this expedition that we now know a lot more about the biodiversity centered on the Sulu-Sulawesi Seas.