The first slavery in the US occurred in Puerto Rico - then ruled by the Spanish. They had enslaved the local indigenous population by 1500. The NYT notes the first delivery of African slaves to the Colonies in 1619, over 100 years later.
I am pretty sure the indigenous people enslaved one another long before Europeans came.
Before Columbus discovered Puerto Rico, who lived there?
The Caribbean had the Arawak, Taino and Carib Indians.
The fate of losing in war to the Carib was worse than slavery...