No license is required in the Hudson itself, as rugman said, it is considered the Marine District.. The marine district used to include creeks and tribs that feed the river, up to the 1st barrier, however the law changed a few years ago, and now a license is required if you fish up in any of the creeks, so stick to the main river. Most of the Creek fishing is real early anyway, once the River gets into the low 50's no need to bother in the creeks.. I don't fish down that far, but up around Kingston I usually start seeing good numbers of schoolies the 1st-2nd week in April most years.. Larger fish are usually around by the 1st week of may, and most years the 2nd week in May is peak time.. By the 1st of June , the water usually has warmed to the point that most of the big schools start to get scarce.. Good Luck!