Micropterus is a genus of freshwater fish in the sunfish family (Centrarchidae) of new-formed order Centrarchiformes (the family used to be in order Perciformes). The species of this genus are known as the black bass. The black bass are distributed throughout a large area east of the Rocky Mountains in North America, from the Hudson Bay basin in Canada to northeastern Mexico. Several species, notably the largemouth and smallmouth basses, have been very widely introduced throughout the world, and are now considered cosmopolitan. All Micropterus species have a dull-green base coloring with dark patterns on the sides. Most reach a maximum overall length of 40–60 cm (16–24 in), but some strains of the largemouth bass have been reported to grow to almost a full meter (just over three feet) in length and weight up to 10 kilos. The male builds a nest in which a female is induced to deposit her eggs, then he fertilizes them. The male continues to guard the eggs and fry until they disperse from the nest. Various species have been introduced into freshwater bodies in Japan, where they have been declared nuisance fish, and subjected to numerous attempts at eradicating them from local ecosystems.
