Its name – Spanish for “Big Mouth” – comes from the mouth of the waterway, called Boca Grande Pass, at the southern tip of the island. The pass was used as a busy shipping point for many years as the waters in the pass are naturally deep. Processed phosphate from the Bone Valley region would be loaded onto waiting cargo vessels via. the Seaboard Air Line Railway at the dock located on the southern tip of the island. Shipping business to the island declined when the Port of Tampa was later dredged and phosphate shipping operations moved north to locations along Tampa Bay. Evidence of the island’s industrial past can still be seen.