Rock Bass

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. 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 (150 and 250 mm), 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 (3.1 lb). It can live as long as 10 years.

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. A population introduced to the Loire River in France between 1904 and 1910 is successfully self-sustaining, but not invasively expanding, more than 100 years later.

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.

Rock bass are sexually mature at about two to three 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 12–15 °C (54–59 °F), with females laying from 2,000 to 11,000 eggs.

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.