Adult rock-bass usually weigh between 1/2 and 3/4 pounds, occasionally reaching 1 pound, and they have been recorded to weigh 3 pounds. The young grow slowly, averaging 2 inches in length during the first six months. Their dorsal fin is much larger than the anal, with 11 spines and 10 rays; the anal fin has 6 spines and 10 rays. Adults are olive-green on the top, greenish-silvery on the sides and white on the belly. Young are often blotched with black, while adults have a dark spot at the base of each scale, forming stripes. (Bowers, 1903).
Range mass: 0 to 1300 g.
Average mass: 0 g.
Other Physical Features: bilateral symmetry
Average lifespan
Status: captivity: 7.0 years.
Average lifespan
Status: captivity: 12.0 years.
Average lifespan
Status: wild: 18.0 years.
Rock bass occupy large lakes, reservoirs, and ponds in the midwest and Mississippi Valley, and they are also found in streams east of the Alleghany Mountains. Rock bass, in the winter months, can be found under ice, yet they can stand a summer temperature as high as 88 degrees F. Though sometimes found in muddy bayous and in waters with decaying vegetation, rock bass thrive best in clear, pure waters well stocked with aquatic plants and small crustacea. (Bowers, 1903).
Aquatic Biomes: lakes and ponds; rivers and streams
Rock bass are native to the Great Lakes region, the Mississippi Valley, and certain streams on the east side of the Alleghany Mountains. They were imported into Germany and other European countries in 1883.
Biogeographic Regions: nearctic (Native )
The main source of food of this species is aquatic plants. They also feed on small crayfish, minnows, tadpoles, worms, and insects. The food of the young consists of minute animals, mainly crustacea and insects, and also vegetation. Some rock bass become cannibalistic in early life, with the larger eating the smaller. (Bergman, 1942).
All bass are fine game fishes, with tournaments being held regularly. Because there are so many bass fisherman their abundance is vital. The indirect value of bass fishing in rural districts, in the expenses of visiting sportsman is immense. Bass fisherman spend billions of dollars each year on guides, accommodations, gas, outdoor clothing, meals, tackle, bait, boats, motors, and permits. Their contribution to the economy is more than sportsmen spend on football and baseball combined. It is estimated that 85 percent of licensed anglers fish for bass. (Bauer, 1955)
There are 9 genera and 30 species in the bass and sunfish family. Rock bass are one of the most abundant fish in the United States. Their adaptability to extreme temperatures has made their introduction to new areas easier than most other fishes. They have been successfully introduced into the western states of California, Washington and Utah. They have also been transplanted into England, France, Germany, and Finland. The artificial breeding of rock bass, by taking and impregnating the eggs, has not been successful. The eggs can only be stripped with great difficulty, and it is necessary to kill the male to obtain the milt. Also, obtaining the eggs and milt at the same time is difficult. Interruption or handling, even during spawning, prevents the discharge of eggs or milt. Artificial ponds for bass are very common in the midwest and southern states. The water must be at least 6-10 feet deep. (Bowers, 1903).
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
Perception Channels: tactile ; chemical
Spawning occurs in spring and early summer, requiring a temperature above 10 degrees celsius. Males make nests in the sand or gravel at a depth of about 1.8 meters. The male cleans the gravel with his caudal fin and tail until every particle is bright. The nest is usually 30 cm in diameter. In the act of spawning, the male and female cross the nest, their stomachs close together, the male a little behind the female, and simultaneously void the eggs and eject the milt. The real act of spawning takes a minute or less. After the female lays the eggs, the male guards the nest. The female may lay 2000 to 10,000 eggs depending on her size. The hatching period takes from one to three weeks. Upon emerging, the young rise in a school and hover over the nest for several days before scattering. The male continues to guard the young during this period. They become sexually mature between 3 and 5 years of age. (Bowers, 1903; Bergman, 1942).
The rock bass (Ambloplites rupestris), also known as the rock perch, goggle-eye, red eye, and black perch, is a freshwater fish native to east-central North America. This red-eyed creature is a species of freshwater fish in the sunfish family (Centrarchidae) of order Perciformes and can be distinguished from other similar species by the six spines in the anal fin (other sunfish have only three anal fin spines).[3]
Rock bass are native to the St Lawrence River and Great Lakes system, the upper and middle Mississippi River basin in North America from Québec to Saskatchewan in the north down to Missouri and Arkansas, south to the Savannah River, and throughout the eastern U.S. from New York through Kentucky and Tennessee to the northern portions of Alabama and Georgia and Florida in the south. The rock bass has also been found in the Nueces River system in Texas.[4]
They are similar in appearance to smallmouth bass, but are usually quite a bit smaller. Identifying characteristics of rock bass are their two dorsal fins that have spinous and soft-rayed united portions, a large mouth, six anal spines, red eyes; rows of dark dots on their sides.[3] The mouth of a rock bass is located in the terminal position, below the snout, with small conical teeth to eat prey. The average rock bass is between 6 and 10 in, and they rarely weigh over a pound. Few rock bass live beyond 10 to 12 years. A. rupestris, the largest and most common of the Ambloplites species, has reached a maximum recorded length of 43 cm (17 in), and a maximum recorded weight of 1.4 kg (3.0 lb).[5] It can live as long as 10 years. These fish have body coloring from golden brown to olive with a white to silver colored belly and have the ability to rapidly change their color to match their surroundings. This chameleon-like trait allows them to thrive throughout their wide range.[6]
Rock bass prefer clear, rocky, and vegetated stream pools and lake margins. Rocky banks of northeastern lakes and reservoirs are a common habitat for rock bass. Their favorite habitat contains some vegetation with rocky bottoms and cool to warm waters.[6] Rock bass species are usually found near rocky shorelines. They can be surprisingly unflustered by the presence of human activity, living under lakeside docks and near swimming areas. Rock bass are frequently seen in groups, particularly near other sunfish.
Large bass, northern pike, muskie, and walleye prey on young rock bass. Rock bass compete with smallmouth bass for food. It is carnivorous, and its diet consists of smaller fish, including their own young at times, yellow perch, and minnows, as well as insects, and crustaceans. Rock bass are occasionally known to take food from the surface. Adult Rock bass may eat heavily, particularly in the evening and early in the morning.[6]
Rock bass are successfully surviving in their environments and are listed as a species of "least concern" on the IUCN Red List. Based on their population stability, rock bass do not require any special monitoring or conservation management plans. As a sport fish, rock bass are managed to some extent by regulations. There are slot limits for rock bass on some bodies of water. Artificial nesting habitat or ponds can be employed to improve rock bass populations.[7]
Rock bass are sexually mature at about 2 to 3 years of age. Rock bass are polygynandrous, in which both females and males have multiple mates during the breeding season. Spawning occurs from April to early June in warm waters ranging from 12 to 15 degrees Celsius, with females laying from 2,000 to 11,000 eggs.[6] Like other members of the sunfish family, the male will dig a nest near the lake shallows, and will aggressively guard it. A spawning area may be heavily used, with several other rock bass nests very close together.[8] As a result, males can become quite aggressive as they attempt to defend territory and attract and hold females. Rock bass lack courtship displays, so the female enters the nest and joins the male in his circular behavior. Both the female and male simultaneously release their sperm and eggs into the nest.[7] The male guards and fans the eggs, and later raises the young for a short time.[3] Rock bass are known to grow quickly.
Rock bass are considered game fish throughout much of their range, the IGFA all-tackle world record for the species is a tie between 1.36kg (3lb) fish caught in York River, Ontario, Canada and Lake Erie, Pennsylvania, USA in 1974 and 1998 respectively.[9]
Ambloplites constellatus (Ozark bass), a species of rock bass from the Ozark upland of Arkansas, and Ambloplites ariommus (shadow bass) are true rock bass, but regarded as separate species. Ambloplites rupestris is sometimes called the redeye or redeye bass in Canada, but this name refers more properly to Micropterus coosae, a distinct species of centrarchid native to parts of the American South. Rafinesque originally assigned the rock bass to Bodianus, a genus of marine wrasses (family Labridae).
Rock bass distribution in the United States 
Ambloplites rupestris 
Ambloplites rupestris in a Quebec aquarium The rock bass (Ambloplites rupestris), also known as the rock perch, goggle-eye, red eye, and black perch, is a freshwater fish native to east-central North America. This red-eyed creature is a species of freshwater fish in the sunfish family (Centrarchidae) of order Perciformes and can be distinguished from other similar species by the six spines in the anal fin (other sunfish have only three anal fin spines).
