TN00013 ROCK BASS AMBLOPLITES RUPESTRIS
Physical description: This is a large-mouthed centrarchid usually with 5 anal spines and a dark margined anal fin. Te adults are usually from 110-200 mm TL. The body is moderately compressed, stocky, and the lateral profile of the head dorsum is convex. The mouth is large and terminal and the eye is large. The pectoral fin is rounded and the caudal is emarginate. The latertal line scales number (35)39-43(45) with (6)7-8(9) scales above the lateral line and (11)12-14(15) scales below the lateral line. There are (10)11(12) dorsal spines, (10)11-12 dorsal rays, 5-6 anal spines, 10-11 anal rays and (12)14-15 pectoral rays. The head dorsum and nape are pale olive to olive-brown and the pale lateral areas are silvery to brassy. The dark lateral stripes are olive-black, and the venter is silvery to brassy with olive-black peppering. The median fins are olive- black to black with pale olive to yellow olive membrane spots. The soft dorsal and caudal have a hint of a black margin and the anal margin in the juvenile and adult are black, boldly contrasted or at least distinctly darker than the remainder of the fin. The pelvic fin occasionally has a dark leading ray, otherwise the pelvic and always the pectoral are uniform pale yellow to olive. The spawning male becomes moderately to very dark over the entire body and the female may be quite blotched *4205*. Reproduction: This is a solitary nester *1187*, and the males construct the nest. The nests are usually constructed on sandy or gravelly bars *2176,1187*. They are also constructed in soil, swampy places, or marl *2176*. Thet may spawn in the nests of other species *1641*. The nest is usually placed beside a rock or stick, but away from any overhanging objects which may block the sun *2176*. This species spawns earlier than most centrarchids, some nesting as early as May 15 *2176*. Spawning is initiated when water temperatures reach 20.5-21 degrees C and may continue until 26 degrees C *788,1200,4205*. Adult females congregate in pools and she approaches a nest only when ready to deposit the eggs *1200*. The female reclines to one side for spawning and the two fish lie side to side in the nest. Only a few eggs are extruded at a time, and at each period milt is extruded by the male. After an hour or more the female leaves the nest *2176*. More than one female may spawn in a nest, and a female may spawn in more than one nest *842*. The male cares for the eggs and fans them. After a few days the eggs are hatched, and the fry grad- ually rise out of the nest and the male leaves *2176*. The eggs are attached to aquatic vegetation and roots in nest. The fertilized eggs are adhesive, and about the size of small shot. Incubation at 20.5-21 degrees C will last 3-4 days *1641*. Females who have not spawned by the end of the breeding season reabsorb their eggs *2176*. The average female lays about 5000 eggs and there is an average of 800 fry per nest *4205*. Behavior: This is a schooling species *1641,788*. They hibernate in summer haunts under leaves and debris or among roots and water willows. They are non-migratory, and unlikely to range through more than a mile of stream in the course of a two year period *1641,1306,1200*. Juveniles, when one month old stay in shallow water over algae covered with stones along the shore, in dense aquatic vegetation, and in the lower course of streams. In lakes they move from the littoral to limnetic zone as development proceeds *1641*. They feed mostly on the bottom, but may feed on the surface. They are both nocturnal and diurnal *788*, and forage mostly at dusk *788,1187*, and at night *1187*. Origin: This species is native, and widely transplanted in Virginia *4205*. Limiting factors: Flooding, predation and fouling of nests by algae were the major causes of brood mortality *4205*. Population parameters: Fecundity ranges from 2,000-11,000 *4205*. The average female lays about 5,000 eggs *1200,4205*. The annual mortality rates were estimateed at 55% from age II and III and at 72% from age IV to V in the Ohio streams, and 66 to 79% for individuals over age V in Nebish Lake with no fishing mortality *788*. Few live more than 5 or 6 years, but occasionally individuals attain an age of 10 years or more *1187*. Aquatic/terrestrial associations: Some fish that they are associated with include Micropterus dolomieui, Pimephales notatus, Hybopsis biguttatus, Notropis rubellus, Hypentelium nigricans, Etheostoma nigrum, E. caeruleum, and E. flabellare. Insects include Coleoptera, Hemiptera, Diptera, Odonata, Mollusca, Crustacea, and Arachnida *1641*. This species competes with the smallmouth bass for food, and probably occurs naturally wherever the smallmouth bass does *1579,842*.
| Life History |
References for Life History Codes
816, 2176, 789, 1641, 788, 1306, 1187, 1200, 842, 4205
Comments on Life History Codes