Depending on which story you believe, the wild rhesus monkeys were brought to Silver Springs in 1933 for the filming of a Tarzan movie, or arrived in 1936 to enhance a jungle cruise tourist attraction. Who ever introduced them to the area thought they could be contained on an island, but found out the monkeys could swim. A 1984 observation counted around 400 monkeys in the colony.
Pretty much what Noe said. I use to do that at least once every summer just to run the boat and cool off during scallop season(can't fish Steinhatchee much then). Fun day to swim and picnic...usually run off by a thunderstorm. In the 8-10 times I have done it I saw the monkeys once. That day I thought the Alpha Male was gonna take our little dog off the bow as he came right to the boat to let us know to keep our distance.