During the American War of Independence, supplies from North America to the British Caribbean were cut off, and combined with a series of hurricanes, resulted in food shortages and famine in western Jamaica. More than a score of slaves at Mesopotamia died as a result, and Joseph's son, also named Joseph, had to purchase a dozen replacement slaves. Between 1774-83, the slave population of Mesopotamia shrank from 278 to 243, so Joseph purchased another 65 slaves to reinforce the workforce. With the slave population at over 300, Joseph now benefited from an income of over £9,000 per annum.Dunn, A Tale of Two Plantations, pp. 36-7.
