Distribution

The smallmouth bass is a freshwater fish originally found in lakes and rivers of eastern and central North America. As a result of widespread introductions, it now ranges from south and central Nova Scotia and New Brunswick, south to Georgia, west to Oklahoma, north to Minnesota, west to North Dakota, and east from southern Manitoba to Quebec. It also occurs in a few areas of western North America and has been introduced in Europe, Asia, and Africa.

Physical Characteristics

• A robust, slightly laterally compressed body.
• Its colour varies from brown, golden brown, olive to green on the back becoming lighter to golden on the sides and white on the belly.
• It has 8-15 narrow, vertical bars on the sides and dark bars on the head that radiate backwards from the eyes.
• Its head is relatively large, with a large red, orange, or brown eye, and its lower jaw protrudes.
• Its two dorsal fins are joined; the front one is spiny and the second one has one spine followed by soft rays.
• Its pelvic fins sit forward on the body below the pectoral fins; a single spine is found on each pelvic fin, and the front of the anal fin.
• Young fish have more distinct vertical bars or rows of spots on their sides and the caudal or tail fin is orange at the base followed by black and then white outer edges.
• Smallmouth bass can weigh over 4 kg (9 lb) in parts of central Canada, but usually do not exceed 1.1 kg (2.5 lb) in Nova Scotia.

Some male smallmouth bass return to the same nest year after year; over 85% of them build their nest within 138 m (150 yd) of where they nested in earlier years.
The world record smallmouth bass was caught in Kentucky, U.S.A. in 1955 and weighed 5.4 kg (11.9 lb). It measured 68.6 cm (27 in) long and 54.9 cm (21.7 in) in girth. The Canadian record was caught in Ontario in 1954 and weighed 9.84 lb.
They have been seen "sunning" in pools with water temperatures of 26.7ºC.

Natural History

Smallmouth bass prefer clear, quiet waters with gravel, rubble, or rocky bottoms. They live in mid-sized, gentle streams that have deep pools and abundant shade, or in fairly deep, clear lakes and reservoirs with rocky shoals. Smallmouth bass tend to seek cover and avoid the light. They hide in deep water, behind rocks and boulders, and around underwater debris and crevices. Smallmouth bass prefer temperatures of 21-27ºC. As temperatures fall, they become less active and seek cover in dark, rocky areas. In the winter they cease feeding, remain inactive on the bottom, and stay near warm springs when possible.

Spawning takes place from late May to early June in shallow (usually 0.3-0.9 m (1-3 ft) deep) protected areas of lakes and rivers, when the water temperature is 16-18ºC.

The male prepares a nest on a sandy, gravel or rocky bottom by cleaning an area 0.3 to 1.8 m (1-6 ft) in diameter. He defends the nest from other males and attracts a series of females into the nest to spawn. After spawning, the female leaves and the male remains to guard the nest and fan the eggs. Females usually produce 5,000-14,000 eggs, depending on their size. The eggs are 1.2-2.5 mm in diameter and stick to stones in the bottom of the nest.

The young are about 5.8 mm long when they hatch in 4 to 10 days depending on the temperature. Sudden changes in temperature or water level can cause the eggs to die from shock or cause the male to abandon the nest, leaving it open for predators. The male protects the young as they absorb their yolk sac and continues to guard them for 3 to 4 weeks until they begin to leave the nest.

Young fish tend to stay in quiet, shallow areas with rocks and vegetation. They begin feeding on plankton (tiny organisms suspended in the water) and switch to larger prey like water insects, amphibians, and other fish as they grow. Two-year old bass are about 12.7 cm (5 in) long.

Older bass prefer rocky, shallow areas of lakes and rivers and retreat to deeper water during high water temperature periods. Most bass do not travel great distances and those in streams spend all season in the same pool. Smallmouth bass mature at ages 3-6, when they are about 17-28 cm (6.7-11 in) long. They are known to live 15 years.

Some smallmouth bass predators are yellow perch, catfishes, white suckers, turtles, and chain pickerel.

For more information contact your local federal or provincial Department of Fisheries, or write to:

Published With Funding from the Canada-Nova Scotia Cooperation Agreement on Economic Diversification, Resource Competitiveness Program.