Researchers find ancient cultures in Mombasa sea


The coastal city of Mombasa is a major Kenyan tourist centre, famed for its Swahili stone town and its past role in the spice, ivory and slave trades. New details of its history are emerging following a pilot study last January of its port and tidal margins involving specialists from the University of Ulster.

The university's Centre for Maritime Archaeology (CMA) is working in Mombasa with scientists from the British Institute in Eastern Africa and the National Museums of Kenya (NMK). The work applied a new research approach, integrating coastal edge, foreshore and seabed archaeology, explained Dr Colin Breen, of the CMA. The seabed and coastal survey involved 16 researchers from the CMA, he said. More than a tonne of equipment was shipped to Mombasa.

Mombasa is of ancient origin. The Periplus of the Erithrean Sea, a second century Greek trade handbook, refers to well-established relationships between merchants from the Gulf of Aden and the inhabitants of a number of east African ports. The accepted scientific view is that contact between Arab traders and the earliest African inhabitants of these ports, probably descended from the ancient Tana tradition, dating from the latter half of the first millennium, in turn led to the prosperous Swahili culture. This flourished along the east African coast from about the eighth or ninth century and survived the Portuguese conquests of the 16th century.

The British Institute and other organisations have sponsored major terrestrial excavations along the Swahili coast, but little was known about archaeological secrets hidden by the sea, explained Dr Athman Lali Omar, head of coastal archaeology at the NMK. "We have very little information about what is in the sea. This kind of investigation is expensive, and Kenya has neither the trained manpower nor the equipment required."

The team from Ulster's CMA has helped to bridge this gap by spearheading a two-week blitz of Mombasa Island, with its complement of divers, geophysical equipment and techniques tested in the much colder waters off the Irish coast. Its aim was to quickly produce as much information as possible about archaelogical remains along the tidal margins.

CMA divers, with assistance from Kenyan navy personnel, used a side-scan sonar towfish, echo-sounder and video cameras to explore the Indian Ocean and mouth of Tudor Creek, where the remnants of Mombasa's early settlements are known to exist. Other team members walked the inter-tidal zone between the high-and low-water marks, surveying this unexplored region.

Not everything went according to plan. The magnetometer, so useful for detecting submerged iron back in Irish waters, proved useless given the weaker equatorial magnetic field. A wealth of material was nonetheless revealed and global positioning system technology helped the team pinpoint the finds and begin to develop a comprehensive map of Mombasa's archaeological landscape.

The resulting picture now includes 49 underwater sites or "anomalies" where materials lie hidden. Among them are two previously unrecorded shipwrecks, one of which most likely dates to the era of Portuguese contact.

The foreshore surveys also yielded five extensive "ceramic scatters", including finds attributable to the Tana tradition. This was the first time that Tana pottery had been recovered in Mombasa, according to the Dr Paul Lane, of the British Institute.

New information about the natural landscape has shed light on one of the early inhabitants' most basic choices - a safe harbour around which to centre their activities, explained Dr Rory Quinn of the CMA. "The old port was located adjacent to a localised deep-water basin, with an average depth of 40 metres - ideal for mooring vessels whilst loading and off-loading goods and allowing for great manoeuvrability," he said.

"Directly to the north is an area of shallower water, which would have served as an anchorage for vessels as they waited for cargo or sheltered from storms."

The integrated landscape approach used by the team promises to unlock many of Mombasa's archaeological secrets, but it also uncovered troubling evidence that much of the city's submerged cultural heritage is at risk of damage or complete loss. The inter-tidal zone is a target for rubbish dumping and raw sewage is pumped into the sea.

The area's most famous wreck, the Portuguese Santo Antonio de Tanna, which sank off Fort Jesus in 1697, is endangered by nutrient-rich sewage effluent which speeds up decomposition of organic materials. Damage is also being done by fishermen who pursue the fish attracted to the ship's remains. The CMA researchers will be working against the clock when they return to Mombasa. Trips are planned for this September and next January.