Why did the Spanish and Portuguese decide they needed slaves?

The decision by the Spanish and Portuguese to rely on enslaved individuals was primarily driven by the need for labor in their sugar plantations, especially after the Native population faced drastic declines due to diseases introduced by European colonizers. The sugar industry was labor-intensive and required a significant workforce to cultivate, harvest, and process the sugarcane. As the Native populations could not fulfill this labor demand due to their reduced numbers, the Spanish and Portuguese turned to Africa for enslaved labor, which became the backbone of their sugar economy and other agricultural endeavors in the Americas. This choice played a critical role in establishing the transatlantic slave trade and had profound implications on demographics, economics, and social structures in the colonies.