178 Bethwell A. Ogotby the 1850s and 1860s, more slaves than ever were still being exported to
Arabia and the Persian Gulf. Moreover, slaves in large quantities were now
needed by the expanding agricultural economy of East Africa.
Most of the successful Arab traders had decided to invest their profit in a
new cash crop—cloves—which had been imported into Zanzibar from Réunion
by about 1820. Between 1835 and 1845, most of the successful Omani traders
became large estate owners, possessing 200-300 slaves per plantation. The large
profits from the clove industry stimulated migration from Oman. According
to estimates, the population of the Omanis in Zanzibar rose from 300 in 1776
to about 5,000 in 1872. In 1877 alone about 1,000 Arabs emigrated from Oman
to Zanzibar. In the 1840s, clove cultivation spread to Pemba, where both Arabs
and the Wapemba themselves took to it.
The clove trade was not limited to the Indian Ocean market. Ameri-
can and European traders took their share of cloves. For example, in 1841,
American traders bought 110,200 pounds of cloves and, in 1859,840,000 pounds.
The French bought cloves worth $47,983 in 1856 and $60,000 in 1859. The
British and the Germans also joined in the trade. Nevertheless, India and Arabia
remained the most important consumers of Zanzibar and Pemba cloves.
The clove planters invested heavily in slaves. By 1849, Zanzibar alone was
estimated to have 100,000 slaves. True, it is difficult to have any accurate popu-
lation censuses at this time. Nevertheless, all estimates by contemporary
observers agree that the slave population in Zanzibar had increased to over
200,000 by 1860 out of a total population of about 300,000. Most of these
slaves were owned by the Omani Arabs and numbered less than 5,000.
Seyyid Said who had acquired forty-five plantations had 6,000 to
7,000 slaves on one plantation alone. Indeed, the period of large and steady
clove harvests coincided with the time when the export of slaves from the inte-
rior of East Africa was greater than ever. According to Cooper, between
15,000 and 20,000 passed through Zanzibar each year. Including slaves that
were sent direct to the Persian Gulf and Arabia, the slave trade of the northern
section of the East African coast was in the neighbourhood of 20,000 to
25,000 slaves a year. According to Curtin, the Atlantic slave trade did not
exceed this magnitude until the eighteenth century.^17
Throughout the nineteenth century, Kilwa was the major supplier of
Zanzibar slaves, drawing them from a wide area, especially from the Lake
Nyasa region and northern Mozambique. The neighbouring peoples such as
the Wahadimu of Zanzibar or the Mijikenda of Kenya, did not provide slaves.
Perhaps the slave traders did not wish to antagonize them because of their
proximity.
What kind of a plantation society emerged in East Africa? By 1860,
many observers were referring to the Arabs as a landed aristocracy. But not
all Arabs were planters, nor were all planters wealthy aristocracy. At the top