There are two reasons the Bass Anglers Sportsmen's Society (B.A.S.S.) tournament trail returns to the Upper Hudson River on a regular basis: plentiful smallmouth and largemouth bass. A prime stretch of bass water flows between Poughkeepsie and Hudson. Focus on the mouths of Catskill Creek, Rondout Creek and Esopus Creek. Also fish along the railroad trestles on the east shoreline. Search along here for "suck holes"-the narrow corridors to back bays. Bass hunt these openings, preying on baitfish caught in the bottleneck. As the tides change, the water flows through these smaller openings, pushing baitfish in and out of the main river. When the water is moving, concentrate on smallies; when the tide is slack, switch to largemouths. Probe chestnut beds in back bays with gold-bladed spinnerbaits or white rats or flip plastics and jig-and-pigs for largemouths. Smallmouths prefer minnows but can be caught on tube jigs and deep-diving shad and crayfish-colored crankbaits. Fish slow and tight to the bottom in the 15- to 20-foot range, focusing your fishing during tide changes. Other good locations are the water-treatment plant south of Port Ewen and the north side of "The Tramway" in Cementon. Contact: Department of Environmental Conservation, Region 3 (845-256-3161; www.dec.state.ny.us).