The fishes grouped in this chapter are typically bass or perchlike in their morphology and appearance. Grunters have bodies that are oblong and compressed slightly, a sloping head with an operculum bearing two spines, and conical or flattened teeth on the jaws. Some species have enlarged "blubber lips" as adults. The dorsal fin is notched with 11-13 spines and 9-11 soft rays. There are 3 spines on the anal fin and 7-10 soft rays. The pelvic fins have 1 spine and 5 soft rays, and are positioned just behind the base of the pectoral fins. The caudal fin may be emarginate, truncate, or rounded. Grunters derive their common name from their ability to contract muscles adjacent to the swim bladder (which acts as an amplifier) to produce gruntlike sounds when alarmed, stressed, or removed from the water. They may reach at least 31.5 in (80 cm) in total length. The temperate basses and austral perches include some of the largest of freshwater fishes, and certainly among the largest perciform fishes. Many have elongate bodies and large mouths, although some have a pronounced hump or steeply sloping head. The dorsal fin is single and notched, and the anterior pelvic fin rays are elongate. Their lateral line is continuous and complete, and their scales are small, primarily ctenoid, but cycloid to a lesser extent.
Percichthyids may reach up to 71 in (180 cm) total length. Blackfishes have slender, elongate bodies; a somewhat blunt snout; a long single dorsal fin; and a somewhat long anal fin. The pelvic fins are jugular xand consist of just a single branched ray. The caudal fin is rounded. The lateral line is reasonably well developed and the scales are minute. Black-
fishes may grow up to 23.6 in (60 cm) total length. Pygmy perches have small, slender bodies; small mouths; interrupted lateral lines that are poorly developed or even absent; and a notched dorsal fin. These fishes are all less than 3.9 in (10 cm) total length, and usually much shorter. Chilean perches are also small, usually less than 3.9 in (10 cm) total length, and have slender, perchlike bodies with truncate or slightly emarginate caudal fins.
Kuhlias are usually oval shaped and compressed, have large eyes relative to the size of their heads, and have a silver or grayish color. The caudal fin is forked or nearly so and often distinctly marked. The dorsal fin has 10 spines, 9-12 soft rays, and is deeply notched. The anal fin has 3 spines and 9-12 soft rays. The opercle has 2 spines, and the pelvic fins lack an axillary process. The lateral line is well developed.
Snooks and giant perches have large, elongate, perchlike bodies. The snout may be concave. Most species are silvery in color. The lateral line is continuous and extends from just behind the gill well onto the caudal fin. The caudal fin may be forked, truncate, or rounded. The dorsal fin is either deeply notched or has a pronounced gap between the first part (7-8 spines) and second part (1 spine and 8-11 soft rays). The anal fin has 3 spines and 6-9 soft rays, and the pelvic fin has 1 spine and 5 soft rays. Males and females are sexually dimorphic for body size, with females being larger. Adults range in size from 7.9 in to over 78.7 in (20-200 cm) total length. The Nile perch is the largest and grows to at least 441 lb (200 kg).
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