TN00352 LONGNOSE DACE RHINICHTHYS CATARACTAE CATARACTAE CATARACTAE
Physical description: This is a medium-size minnow with a robust body, tiny scales a moderately posterior dorsal fin placement and a ventral mouth with a barbel at each corner. The adults are usually 60-85 mm SL. The body is streamlined, anteriorly robust, and the caudal peduncle is moderately deep. The head is moderate with a small eye and a markedly downsloping snout. The mouth is U-shaped with fleshy lips. The nuptial male has small densey spaced tubercles on the head and snout, with tiny tubercles on the body except for the breast. The pectoral has a thickened leading ray and moderate size recurved tubercles. The other fins have tiny tubercles. The female lacks tubercles and the pectoral, dorsal, and pelvic fins have gustatory papillia. The genital papilla of the male is reletively small and triangular, with that of the female reletively large and fleshy. They have 2,4-4,2 pharyngeal teeth and the lateral line is complete with 61-75 scales. There are 25-30 circumpeduncle scales, 8 dorsal rays, 7 anal rays, (7)8 pelvic rays and (12)13-17 pectoral rays. The nuptial male has a dark olive or black-olive dorsum and upper side with the side light olive, sometimes with a bronze iridescence. The side is mottled with scattered black scales and the lower side is straw-olive. The caudal peduncle will sometimes have a pale red cast and the breast and belly are whitish. The remaining venter is dusky with olive-black pigment. The head dorsum, snout, and cheek are olive-black, the cheek sometimes with flecks of green iridescence. The lower lip and gular are white. The dorsal fin is dull to bright dark red in the membrranes. The rays are dark too light olive. The caudal spot is black and the caudal fin is the same as the dorsal. The annal and pelvic fins have a pale red cast and the pectoral is dark red in the membranes with the rays dusky black-olive *4205*. Reproduction: The breeding season is in April and May in Virginia with the majority of June adults spent. They spawned in May and June in a Manitoba river, and in Lake Michigan spawning began in late May and peaked in late June and early July. They are known to spawn in May in Maryland *2256,2259,1389*. The eggs hatch in 3-4 days after fertilization *2251*. Lake Michigan populations produced 870-9953 eggs/female *2259*. The age at maturity is 2 years *2257,2259*. In lakes most males move to onshore waters less than 3 feet deep, and the females may wait in deeper offshore waters until ripe. In streams and rivers the males move to small rock riffles while the females stay in larger rock riffles except to spawn. Spawning may occur in daylight or at night. Males are ter- ritorial and will court a female by nudging her abdomen from below with his nose. The male will display body trembling when a female is within 12 cm of his territory, and he will also probe the substrate with his nose especially when a female is in his territory. A receptive female will push her nose in the substrate where the male has, and as the female does this the male quivers in a position parallel to the female. Spawning occurs over the depression they have made from probing and at this time the male and female both display trembling *2256,2257,2259,2258,4205*. Aggressive behavior consists of chasing and biting. In Virginia, the females may deposit from 200-1200 eggs with a total ova range of 1400 to 2800 *4205*. Behavior: This species has a non-random dispersion *1114,1475,842*. They are territorial in the breeding season, males only, prior, during, and after spawning with eggs *2257,2258*. This species mainly feeds on benthos but is known to jump a few inches into air to catch insects *2257,2256,2266,1473,1476*. They will occationally take worms mites and algae *4205*. This species spawns in lakes in the littoral zone over rock or gravel-rock substrate. In streams and rivers they spawn over large stones or small rocks in fast riffles. They may use river chub (Nocomis micropogon) sites if spawning habitat is scarce *2256,2257,2259, 2258,2251,4205*. Fry are from 4.5-5.9 mm TL long at birth, and the yolk sac is absorbed 6-8 days after hatching. Larvae remain in slow water along the margin in rivers and move into faster currents and riffles as they pro- ceed into the juvenile stage *2266,2251,4205*. Origin: This species is native in Virginia and introduced into the Roanoke drainage *4205*. Population parameters: Sources give varied reports of sex the ratio: (male:female) age II=77:47, 12:49; age III=22:73, 9:51, 1:1; age IV=0.47:1; age V=0:1 *2256,2259,1476*. A few studies on physiology relating to bouyancy and the swimbladder are in the literature *2272,2254,2255*. One study was done on the use of an isozyme to determine hybridization between the longnose and blacknose dace (R. atratulus). One study was done relating behavior and circadian rhythm *2253*. This species forms natural hybrids with the common shiner (Notropis cornutus) and the river chub (Nocomis micropogon). One source describes genetic variability within the species *2251,2269,2270*. TN00352PHYSICAL DESCRIPTION: ORBITAL DIAMETER ABOUT EQUAL TO DISTANCE FROM TIP OF SNOUT TO ANTERIOR TIP OF LOWER JAW IN R. ATRATULUS THE DIAMETER IS MUCH GREATER *TN5057*
| Life History |
References for Life History Codes
1114, 1115, 1475, 842, 835, 2258, 2251, 2259, 2269, 1389, 2257, 2266, 1476, 1473, 2270, 2272, 2254, 2255, 2273, 2253, 4205
Comments on Life History Codes