The end of slavery marked the beginning of a long economic decline in the Virgin Islands [1]. The Danes and British did very little to support the newly freed slaves, and many of the planters pulled out. Left virtually alone, the former slaves turned to subsistence farming, fishing, and small-scale trade to survive. St. Croix was the only island that maintained a sugar industry significantly beyond the end of slavery; its last sugar mill closed in the 1960s.
Links:
[1] http://www.moon.com/destinations/virgin-islands/discover-the-virgin-islands