The survivors who disembarked were, if not all contracted for by a single employer, lined up in slave-market style and offered for sale (i.e., nominally, sale of the contract to be paid in installments) to labor agents at dockside. Agents would then dispose of the migrants to the ultimate employers. Most (probably 80 percent) were destined for plantations of cotton or sugar, where formerly African slaves had labored, but some particularly unfortunate ones were destined to mine and pack guano: aged bird manure, a natural fertilizer collected on islands along the coast. The sufferings of the guano workers drove many to suicide.