Latin name

Ambloplites rupestris

Other names

Black perch, goggle-eye, red eye, rock sunfish, goggle-eye perch; French: crapet de roche.

Identification

Although in appearance it resembles something between a bluegill and a black bass, the rock bass is actually a large and robust sunfish with a deep body, less compressed than most sunfish, and shaped more like a black bass. The back is elevated, and the large head is narrow, rounded, and deep. The mouth of the rock bass is large compared to other sunfish. The upper jaw extends beyond the beginning of the eye, but does not reach the back of the eye. It has two connected dorsal fins, five to six anal fin spines, and large eyes. On the back and sides, it is olive-brown or bronze, with faint lines of small dark spots. The centers of the scales below the lateral line also have dark markings that form 11 or more rows and give the fish a striped appearance. Some rock bass, have lighter but uniform coloration underneath, while others have a silvery, gray or white belly. The pelvic fins have pale round spots, and all fins are usually darker around the edges, although the edges of the anal spines are white, the tips of the pectoral fins are transparent, and the pelvic fins sometimes have a white edge. A distinctive feature is the bluish-black blotch on the tips of the gill lids. The rock bass is often confused with Lepomis gulosus. Lepomis gulosus has teeth on its tongue, while the rock bass does not. In addition, the rock bass has six spines in front of its anal fin, unlike the three spines of Lepomis gulosus. Rock bass can also resemble Sunfish, Mud. The rock bass has a forked tail and coarse scales, whereas the Sunfish, Mud, has a rounded tail and smooth scales.

Distribution

Native to the northeastern United States and southeastern Canada, the rock bass is found from southern Manitoba eastward to Ontario and Quebec, and southward through the Great Lakes region and the Mississippi Valley to the Gulf of Mexico and into northern Alabama and northern Georgia. They have been introduced into other states as well, including some in the western United States.

Habitat

Rock bass prefers small and temperate streams with cool and clear water, plenty of cover, and strong currents. It is abundant in small, weedy lakes and on the outer edges of large lakes, as well as in thousands of small lakes and ponds. It almost always stays on rocky bottoms (hence the name) where there is no silt. Juveniles are often found in vegetation. The fish tend to frequent the same habitats as the smallmouth bass.

Size

The most common size is about 8 ounces, although it has been known to reach 3 pounds. Often, rock bass weigh about a pound, and some fish exceed 2 pounds. However, as with most sunfish, size is highly variable, and brook fish are often undersized. The record holder of all tackle is the 3-pound Canadian fish. Rock bass can reach a length of 12 to 14 inches, but are usually less than 8 inches long. Although aquarium fish live up to 18 years, they live an average of 10 to 12 years in the wild.

Life history and Behavior

Rock bass are capable of breeding when they are 2 years old or have reached a length of 3 to 5 inches. Spawning occurs from mid-spring to early summer, when water temperatures range from 60° to 70 °F. The males enter shallow water 3 to 4 days before the females emerge to establish their territory. They begin building round nests in gravel or sandy areas near thickets of weeds or other protective structures such as submerged tree trunks, using their pectoral, anal, and caudal fins to rake the gravel for nests. Spawning occurs during the day, usually in the morning. Females spawn at least twice, going from nest to nest and laying a total of 3,000 to 11,000 eggs. The males guard the nests until the eggs hatch and the young swim away, and many males nest a second or even third time. This fish is mischievous and often congregates with other sunfish and smallmouth bass.

Food and feeding habits

Young rock bass feed on small aquatic life during infancy and, as they grow, on insects and crustaceans. Adults feed mainly on crustaceans, but also on insects, mollusks and small fish. This diet varies depending on the season and habitat. Due to their large mouths, they can consume relatively large specimens. The fish usually feed at the bottom, but may occasionally feed near the surface.

Reproduction

No information