The genus name Micropterus is Greek, meaning "little fin". The species name "dolomieu" recognizes Comte Déodat de Dolomieu.
Micropterus dolomieu was originally described by Lacepède, who named the species in 1802.
Although large adults are often the top predatory fish in their habitats, young adults and juveniles are often preyed upon by other fish (including other smallmouth bass) and turtles (Scott and Crossman, 1973). Osprey and kingfishers are known avian predators on adult and juvenile largemouth (Cooke et al., 2003b). These and similar birds are also known to eat smallmouth bass.
Known Predators:
Like all other species of the genus Micropterus, the smallmouth bass has a moderately compressed, elongate body. There are 3 spines in the anal fin, and 9-11 spines in the dorsal fin. Body is olive green above, yellow-white below, typically with 8-16 dark brown vertical bars on the side. The mouth is large, with the posterior edge of the maxilla extending to beneath the eye. Similar species include M. salmoides, M. punculatus, and M. coosae (Page and Burr, 1998). Average adult length ranges from 30-50 cm (15-20 in) (Mettee et al., 1996). Some populations have small tooth patches on the tongue (Etnier and Starnes, 1993).
Range length: 30 to 50 cm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike
Average mass: 2975.5 g.
Average life span is between 6 and 14 years (Carlander, 1977).
Range lifespan
Status: wild: 26 (high) years.
Typical lifespan
Status: wild: 6 to 14 years.
Although its native distribution overlaps much of the northern range of Micropterus salmoides, M. dolomieu typically is found in cooler rivers and lakes, with rocky or sandy substrates (Berra, 2001). As visual predators, smallmouth bass actively seek out clear waters (Sweka and Hartman, 2002). Increases in turbidity can cause displacement of many fish species, M. dolomieu included (Larimore, 1975). In lakes, smallmouth seek out structures, such as logs, rocky outcroppings, or pier posts (Etnier and Starnes, 1993). When present in stream ecosystems, they are typically found in areas with a relatively swift current (Probst et al., 1984).
Habitat Regions: temperate ; tropical ; freshwater
Aquatic Biomes: lakes and ponds; rivers and streams
The native range of Micropterus dolomieu encompasses the Great Lakes and the St. Lawrence seaway drainages from southern Quebec and New Hampshire to North Dakota, and the Mississippi River drainage as far south as Alabama (Page and Burr, 1998). It shares most of its range with the largemouth bass, Micropterus salmoides (Near et al., 2003). Beginning in 1873 with introduction to Belgium, the smallmouth bass has been introduced to South Africa, Scandinavia, the British Isles, France, Germany, The Czech Republic, Mexico, Belize, Austria, Slovakia, Vietnam, Guam, Fiji, and Hawaii (Welcomme, 1988). It has also been introduced to parts of the United States and Canada outside its natural range.
Biogeographic Regions: nearctic (Introduced , Native ); palearctic (Introduced ); ethiopian (Introduced ); neotropical (Introduced ); oceanic islands (Introduced )
Fry and juvenile diets consist primarily of zooplankton and insect larvae. Adults have a more diverse palate, subsisting on such varied foods as crayfish, amphibians, insects, and other fish (Scott and Crossman, 1973; Etnier and Starnes, 1993). Adults also cannibalize young of other parents (Scott and Crossman, 1973).
Animal Foods: amphibians; fish; insects; aquatic crustaceans; zooplankton
Plant Foods: phytoplankton
Primary Diet: carnivore (Piscivore , Insectivore , Eats non-insect arthropods); planktivore
Micropterus dolomieu often acts as a top predator in the systems it inhabits, primarily as a piscivore, but also taking a large proportion of macroinvertebrates. Young smallmouth are a major source of larval fish mortality (Etnier and Starnes, 1993). Smallmouth have been shown to reduce abundance of many small-bodied cospecifics, sometimes to the point of local extirpations (MacRae and Jackson, 2001).
An important sport fish throughout its range, the smallmouth is almost as popular as the largemouth bass. It is also a popular food fish (Scott and Crossman 1973). In many states, taxes on the sales of fishing rods and tackle, as well as proceeds from the sale of licenses contribute a large part of the budget for natural resource management organizations.
Positive Impacts: food ; ecotourism
Larvae are typically 2.2-2.5 mm long at hatching. The notochord flexion occurs at a length of 6-9 mm. Dorsal and anal fins are typically completely formed by the time the fish has reached 7-13 mm. Fins form in the following sequence: soft-rayed dorsal, anal, spinous dorsal, pelvic, pectoral. Rays first appear in the approximate middle of the area the complete ray will encompass, and expand proximally and distally until reaching full size. The caudal fin is typically complete by the time the dorsal and anal fins have their full complement of soft rays. First scales appear towards the end of the larval period, when the fish is approximately 14-18 mm in length (Johnson 1983).
Micropterus dolomieu is not a conservation concern. Like M. salmoides, M. dolomieu is an important game fish. Each year, millions of dollars are spent by anglers in search of bass. Renowned for its fighting ability and tasty flesh, the smallmouth is fished for sport throughout its range (Etnier and Starnes, 1993).
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Smallmouth bass are highly visual predators; they require clear waters to be truly effective. Increasing turbidity decreases reactive distance significantly, ultimately reducing overall prey consumption. However, once a prey item has been reacted to, turbidity does not have an impact on capture success (Sweka and Hartman, 2003).
Communication Channels: tactile ; chemical
Perception Channels: visual ; tactile ; chemical
Like other centrarchids, the male will excavate and guard a small, round nest. Suitability for nest-building is maximized between 1-2.5 m in depth, with particle size of substrate near 30 mm (Clark et al., 1998). Several females may spawn in the nest of one male (Etnier and Starnes, 1993). Individual females may also spawn in the nests of several males.
Mating System: polygynandrous (promiscuous)
When a female enters the male's territory, a complex dance occurs, with the pair rubbing and biting each other. The actual act of spawning occurs in about 5 seconds, and is repeated for up to 2 hours. Females lay upwards of 2,000 eggs at each spawning (Smith, 1979). After spawning is complete, the female is chased off, and will occasionally mate again with another male. The eggs hatch in 4-6 days, and the fry remain in the nest for approximately two weeks before dispersing (Neves, 1975; Scott and Crossman, 1998).
Breeding season: Spawning typically occurs between March and May. Onset is based mainly on degree-days, when temperatures exceed 10°C (Shuter et al., 1980). In the extreme northern tail of its distribution, spawning may be delayed a month, and begin in April and run through June.
Range gestation period: 2 to 3 days.
Average time to independence: 2 weeks.
Range age at sexual or reproductive maturity (female): 3 to 4 years.
Range age at sexual or reproductive maturity (male): 3 to 4 years.
Key Reproductive Features: seasonal breeding ; sexual ; fertilization (External ); broadcast (group) spawning; oviparous
Parental care in M. dolomieu is the sole responsibility of the male, who guards the eggs and fry for an extended length of time (Cooke et al., 2003a). Temperature variation of as little as 2°C can result in abandonment of the nest, especially when water temperature drops below 15°C (Rawson, 1945; Latta, 1963).
Parental Investment: pre-fertilization (Provisioning); pre-hatching/birth (Protecting: Male); pre-independence (Protecting: Male)
The smallmouth bass (Micropterus dolomieu) is a species of freshwater fish in the sunfish family (Centrarchidae) of the order Perciformes.[3] It is the type species of its genus Micropterus (black basses), and is a popular game fish sought by anglers throughout the temperate zones of North America, and has been spread by stocking—as well as illegal introductions—to many cool-water tributaries and lakes in Canada and more so introduced in the United States.[4] The maximum recorded size is approximately 27 inches (69 cm) and 12 pounds (5.4 kg).
The smallmouth bass is native to the upper and middle Mississippi River basin, the Saint Lawrence River–Great Lakes system, and the Hudson Bay basin.[5] Its common names include smallmouth, bronzeback, brown bass, brownie, smallie, bronze bass, and bareback bass.
Smallmouth have a slender but muscular fusiform body shape making them powerful swimmers.[6] The coloration of the smallmouth bass' ctenoid scales range from golden-olive to dark brown dorsally which fades to a yellowish white ventrally with dark brown vertical bars or blotches along the body and dark brown horizontal bars on the head.[7] The combination of the muscular fusiform body shape and camouflage like coloring make these fish highly effective ambush predators. The coloration can vary greatly depending on the fishes age, habitat, water quality, diet, and the spawning cycle.
Generally, the protruding jaw of the smallmouth does not extend past the eyes which are red or brown. They have two dorsal fins which are separated by a shallow interdorsal notch. The front dorsal has 9-11 spiney rays and the back dorsal has 13–15 soft rays.[8]
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 and coloration can differ, depending on if they are found in lacustrine or riverine habitats. Smallmouth found in riverine habitats are generally long and slender which allows greater agility in moving water, while those found in lacustrine habitats and shorter and deeper bodied.[9] Riverine smallmouth that live in dark water tend to be rather torpedo-shaped and very dark brown to be more efficient for feeding.[10] Lacustrine smallmouth bass, however, that live in sandy areas, tend to be a light yellow-brown and are more oval-shaped.[11]
There are two recognized subspecies, the Northern smallmouth bass (M. dolomieui dolomieui) and the Neosho smallmouth bass (M. dolomieui velox).[12] The Northern smallmouth bass is much more widespread than the much smaller subgroup called the Neosho smallmouth bass. The Neosho are native to an ecologically isolated region of the lower Midwest known as the Central Interior Highlands, which weave through southwestern Missouri, northern Arkansas and northeastern Oklahoma.[13]
They eat tadpoles, fish, aquatic insects, and crayfish.[14][15]
The world record size was 11.94 pounds (5.42 kg) caught in the reservoir Dale Hollow, on the Kentucky—Tennessee border.[16]
The smallmouth bass is found in clearer water than the largemouth, especially streams, rivers, and the rocky areas and stumps and also sandy bottoms of lakes and reservoirs. It can also survive in a stronger current than other black bass. The smallmouth prefers cooler water temperatures than its cousin the largemouth bass, and as a result will often seek out deeper, faster moving water during the hot summer months. Because it is intolerant of pollution, the smallmouth bass is a good natural indicator of a healthy environment, though they are still much more resilient than most trout species. Carnivorous, its diet comprises crayfish, amphibians,[17] insects, and smaller fish, while the larvae feed on various zooplankton[18] and insect larvae.[19] Adults also cannibalize young of other parents.[20]
The female can lay up to 21,100 eggs, which are guarded by the male in his nest.
When the weather gets colder, and the water temperature drops below 15 C (60 F), smallmouth will often migrate in search of deeper pools in which they enter a semi-hibernation state,[21] moving sluggishly and feeding very little until the warm season returns.[21] The migration patterns of smallmouth have been tracked and it is not unusual for a smallmouth to travel 12 miles in a single day[21] in a stream, creek or river.[21] The overall migration can exceed 60 miles.[21]
Smallmouth generally begin spawning patterns in spring or early summer when water temperatures are between 15–18 °C (59.0–64.4 °F), which is heavily dependent on latitudinal location.[22] Smallmouth require clean stone, rock, or gravel substrate for a successful spawn.[23]
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.[24][25]
With increased industrialization and land use changes, many of the nation's eastern trout rivers were polluted or experienced elevated water temperatures, reducing the range of native brook trout. Smallmouth bass were often introduced to northern rivers with increased water temperatures 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.[24][26]
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.[27][28] The smallmouth bass is potentially the toughest fighting freshwater fish in North America, and is commonly the targeted species in many fresh water fishing tournaments.[29] 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".[30] Smallmouth bass are not usually taken for the table, but rather are caught and released by most anglers. However, smaller specimens in cooler water often have higher quality filets of white, firm flesh when cooked.[31]
The current all-tackle world record for a smallmouth bass is 11 lb 15 oz, caught by David Hayes[32] in the Dale Hollow Reservoir, on the Kentucky/Tennessee border, in 1955.[33]
In conventional fishing, smallmouth may be successfully caught on a wide range of natural and artificial baits or lures, including crankbaits, hair jigs, plastic jerkbaits, artificial worms, spinnerbaits, and all types of soft plastic lures, including curly tail grubs or tubes with lead head jigs. Spinning reels or baitcasting reels may be used, with line strengths of 6 to 15 pounds typically utilized. According to many, smallmouth typically put up a better, more exciting fight than any other black bass. Rods are usually of ultralight to medium-heavy action. They may also be caught with a fly rod using a dry or wet artificial fly, nymphs, streamers, or imitations of larger aquatic creatures, such as hellgrammites, crawfish, or leeches. Floating topwater popper fly patterns and buzz baits are also popular for smallmouth fishing.[27][28]
For river fishing, spinning tackle or fly tackle has been the most popular angling tools for smallmouth in North America for many years. When fishing in colder water, it is believed to be more effective to fish with smaller lures like hair jigs or small spinners. During the rest of the year, smallmouth are usually taken using soft plastic tubes or spinnerbaits. The best spots in rivers to fish for smallmouth are behind rocks or in eddies, where water swirls around. Smallmouth can also be taken in cool lakes like Lake Erie or any of the northern lakes.
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 Micropterus (black basses), and is a popular game fish sought by anglers throughout the temperate zones of North America, and has been spread by stocking—as well as illegal introductions—to many cool-water tributaries and lakes in Canada and more so introduced in the United States. The maximum recorded size is approximately 27 inches (69 cm) and 12 pounds (5.4 kg).
The smallmouth bass is native to the upper and middle Mississippi River basin, the Saint Lawrence River–Great Lakes system, and the Hudson Bay basin. Its common names include smallmouth, bronzeback, brown bass, brownie, smallie, bronze bass, and bareback bass.
Smallmouth Bass Range Map
