The smallmouth bass (Micropterus dolomieu) is a species of freshwater fish in the sunfish family (Centrarchidae) of the order Perciformes. It is the type species of its genus. One of the black basses, it is a popular game fish sought by anglers throughout the temperate zones of North America, and has been spread by stock to many cool-water tributaries and lakes in Canada and more so introduced in the United States.
Males are generally smaller than females. The males tend to range around two pounds, while females can range from three to six pounds. Their average sizes can differ, depending on where they are found; those found in American waters tend to be larger due to the longer summers, which allow them to eat and grow for a longer period of time. The female can lay up to 21,100 eggs, which are guarded by the male in his nest.
In the United States, smallmouth bass were first introduced outside of their native range with the construction of the Erie Canal in 1825, extending the fish's range into central New York state. During the mid-to-late 19th century, smallmouth were transplanted via the nation's rail system to lakes and rivers throughout the northern and western United States, as far as California. Shippers found that smallmouth bass were a hardy species that could be transported in buckets or barrels by rail, sometimes using the spigots from the railroad water tanks to aerate the fingerlings. They were introduced east of the Appalachians just before the Civil War, and afterwards transplanted to the states of New England.
With increased industrialization and development, many of the nation's eastern trout rivers were nasty, polluted, or allowed to silt up, raising water temperatures and killing off the native brook trout. Smallmouth bass were often introduced to northern rivers now too warm for native trout, and slowly became a popular gamefish with many anglers. Equally adaptable to large, cool-water impoundments and reservoirs, the smallmouth also spread far beyond its original native range. Later, smallmouth populations also began to decline after years of damage caused by overdevelopment and pollution, as well as a loss of river habitat caused by damming many formerly wild rivers to form lakes or reservoirs. In recent years, a renewed emphasis on preserving water quality and riparian habitat in the nation's rivers and lakes, together with stricter management practices, eventually benefited smallmouth populations and has caused a resurgence in their popularity with anglers.
Today, smallmouth bass are very popular game fish, frequently sought by anglers using conventional spinning and bait casting gear, as well as fly fishing tackle. The smallmouth bass is one of the toughest fighting freshwater fish in North America. In addition to wild populations, the smallmouth bass is stocked in cool rivers and lakes throughout Canada and the United States. In shallow streams, it is a wary fish, though usually not to the extent of most trout. The smallmouth is highly regarded for its topwater fighting ability when hooked – old fishing journals referred to the smallmouth bass as "ounce for ounce and pound for pound the gamest fish that swims". Smallmouth bass are taken for the table, with filets of white, firm flesh when cooked. Today, many fishermen practice catch-and-release fishing to improve fish populations.