Shipwreck Shines Light on Slave Trade

A longer route from Africa to South America brought cheaper captives and less competition, but greater risks. The sunken remains of one of the first ships to use that route have been discovered.

By Greta Weber
Adapted from "Shipwreck Shines Light on Historic Shift in Slave Trade," by Greta Weber, news.nationalgeographic.com, June 5, 2015


In December 1794, Portuguese slave traders on the east coast of Africa outfitted their vessel for a dangerous voyage. The 7,000-mile, months-long journey from Mozambique round South Africa and across the Atlantic to Brazil was risky. However, there was money to be made. More than 400 men, women, and children lay chained in the ship's hold. Their fates were bound to the merciless law of supply and demand.

The ship, the Sao Jose Paquete, would never make it to Brazil. Its sunken remains have sparked global media coverage of the 18th-century slave trade. A team of investigators from the United States and some African countries announced the ship's identity in 2015 after quietly researching the site since 2010. Treasure hunters discovered the site in the 1980s but thought it was a Dutch merchant ship. The Iziko Museums of South Africa revealed telltale artifacts. Among the finds were iron ballast bars, a wooden pulley, and copper nails.

The Sao Jose Paquete is the only ship found to date that sank with human cargo trapped inside. It is a valuable find for nautical archaeologists and slave trade scholars. It is also one of the first known ships to attempt the long-distance passage linking Portugal to Mozambique to Brazil.

Indeed, the ship's global journey represents European slave traders' increasingly desperate attempts to find slaves to trade. More than two centuries of cruel commerce along Africa's west coast had exhausted the populations that had supplied them. Rising competition pushed Portugal thousands of miles further east to one of the farthest, cheapest sources of slaves.

About 25 million people lived in the 4,000 miles of coastline between Senegambia and Angola, the major vein of the West African slave trade supply. Europeans started to take slaves from these areas in the early 16th century. The Portuguese made the first slave voyage from Africa to the Americas in 1526. By 1600, almost all of the slave ships from the whole of sub-Saharan Africa came from the west-central region.

Most of the slaves at this period were going to the Spanish Caribbean or Brazil. There, over two thirds of all enslaved Africans landed to produce crops such as sugar, tobacco, rice and cotton. Brazil would supply nearly all of the sugar consumed in Europe. By the 1640s, the northeastern state of Pernambuco alone exported more than 24,000 tons of sugar annually to Amsterdam.

"There's an old saying by the abolitionists that sugar was made with blood," says Marcus Rediker, a history professor at the University of Pittsburgh. He has written extensively about the slave trade. "People were worked so hard on the sugar plantations that many of them were worked to death." This required a constant stream of replacements.

European slave-trading strategies were ruthless. Traders supplied their African allies with guns and gunpowder to intensify tribal warfare. African middlemen would then attack enemy kingdoms, capture slaves, and march them to the coast to sell to European traders. But this system could not go on forever.

As the slave trade bore on into the 18th century, demand for goods produced in the Americas was on the rise. Sugar production was an extremely successful and profitable business that demanded more and more African slave labor.

African middlemen struggled to meet the heightened demand. They traveled deeper inland to find and capture bodies with what Europeans considered prime working hands. "Over the course of the 18th century, which really is the peak period of the slave trade, the availability of those prime working hands is diminishing in traditional outlets," Rediker says.

Faced with a smaller supply of captives along Africa's west coast, Portugal searched elsewhere. East Africa offered cheaper, less competitive sources. "Slavers had a hard time paying the prices necessary to get slaves from ports that were somewhat closer," says Walter Hawthorne, professor of African History at Michigan State University.

This is probably why the Sao Jose risked the dangerous journey with a higher casualty rate. One Portuguese vessel, ironically named The Protector, lost 339 slaves of the 807 aboard during a journey from Mozambique to Brazil.

Of the 12 to 13 million slaves loaded onto ships during the trans-Atlantic trade, only about 400,000 of them came from Eastern Africa. Rediker estimates that a few hundred voyages out of 60,000 came from Mozambique during that period.

When the Sao Jose started to go down, its crew could save only half of its precious human cargo. More than 200 African men and women died still chained to the doomed ship. No human remains have been found so far, but Rediker considers the wreck, "a graveyard of the vessel and the people trapped aboard it."