sturgeon and dwarf wedgemussels. Additionally, the United States Fish and Wildlife Service has repopulated the river with another species of migratory fish, the Atlantic salmon, which for more than 200 years had been extinct from the river due to damming. Several fish ladders and fish elevators have been built to allow fish to resume their natural migration upriver each spring. Fresh and brackish water residents of the main branch and tributaries include common carp, white catfish, brown bullhead, fallfish, yellow perch, smallmouth bass, largemouth bass, northern pike, chain pickerel, bluegill, pumpkinseed sunfish, golden shiner, and rock bass. Much of the beginning of the river's course in the town of Pittsburg is occupied by the Connecticut Lakes, which contain lake trout and landlocked salmon. Landlocked salmon make their way into the river during spring spawning runs of bait fish and during their fall spawn. The river has fly-fishing-only regulations on of river. Most of the river from Lake Francis south is open to lure and bait as well. Two tail-water dams provide cold river water for miles downstream, making for bountiful summer fishing on the Connecticut. After the first major dam was built near Turners Falls, Massachusetts, thirteen additional dams have ended the Connecticut River's great anadromous fish runs. Salmon restoration efforts began in 1967, and fish ladders at a fish elevator at Hadley Falls have since enabled migrating fish to return to some of their former spawning grounds. In addition to dams, warm water discharges between 1978 and 1992 from Vermont Yankee Nuclear Power Plant in Vernon, Vermont released water up to degrees, with the thermal plume reaching downstream as far as Holyoke. This thermal pollution appears to be associated with an 80% decline in American shad fish numbers from 1992 to 2005 at Holyoke Dam. This decline may have been exacerbated by over-fishing in the mid-Atlantic and predation from resurging striped bass populations. The nuclear plant was closed at the end of 2014, after which the shad population has increased. Economy Boating The mouth of the river up to Essex is thought to be one of the busiest stretches of waterway in Connecticut. Some local police departments and the state Environmental Conservation Police patrol the area a few times a week. Some towns keep boats available if needed. In Massachusetts, the most active stretch of the Connecticut River is centered on the Oxbow, north of Springfield in the college