Riverkeeper John Cronin, 1983. Photo, Don Nice. Courtesy of Riverkeeper. Beginning in 1972, the Hudson River Fishermen’s Association began a “Riverkeeper” program to patrol the river. Ten years later, Riverkeeper John Cronin and his boat were monitoring the river full-time. On Cronin’s first day, he confronted an Exxon tanker discharging polluted ballast water into the river. In 1986, the Hudson River Fishermen’s Association merged with its Riverkeeper program to form one group to protect the river. Images courtesy  New-York Historical Society Museum & Library.