The Longnosed Dace, Rhinichthys cataractae, in Wisconsin and Wyoming WatersBy Dr. F.A. Copes
reprinted from American Currents, Spring 1982
The longnose dace ranges from British Columbia in the west to Newfoundland in the east, south to Pennsylvania and Oregon, and down the Appalachian Mountains to South Carolina and the Rockies to New Mexico and west Texas (Trautman, 1957). The longnose dace is present on both sides of the Continental Divide in Wyoming and is one of the most widely distributed of the western fishes (Simon, 1951). The longnose dace is confined to the streams in the northern half of Wisconsin (Green, 1935).
The longnose dace was the third most abundant cyprinid collected in this study. It is considered an excellent forage fish in waters which contain game fish. Life history studies of this species have been conducted by Becker (1962) in Wisconsin, Kuehn (1949) in Minnesota, and Reed (1959) in Pennsylvania. Gee and Northcote (1963) and Gerald (1966) investigated the feeding habits of the longnose dace.
Area of Study
Habitat and Behavior
The longnose dace is primarily a schooling species and the schools were generally found in sheltered areas, but were observed in all types of habitats. The school had no apparent leader, but larger fish were usually observed at the head and in the middle of the schools and smaller fish in the edges and near the rear of the school. Schools of longnose dace were observed to be very active when the stream flow or turbidity was increasing, on dark cloudy days, and at dusk. Larger longnose dace tended to avoid direct sunlight. The schools of longnose dace generally contained from 5 to over 100 fish. Spacing of individual fish in schools varied greatly.
In Sand Creek, age-class 0 longnose dace were observed in open areas of shallow riffles and runs, and they avoided deeper areas where larger fish were found. Schools of age-class 0 fish were found with schools of young creek chubs and they often formed mixed schools. In Marengo River, schools of age-class 0 longnose dace were found in areas of reduced current and shallow runs.
Schools of adult longnose dace were observed in open areas of runs and riffles at night. They appeared to be active during the early hours of darkness. Longnose dace were not found in any abundance in fast runs and riffles in November. They wintered in large schools and pods under shelter in heavily shaded slow runs and pools. Several hundred longnose dace were found in November among the beaver cuttings in the face of an old beaver dam. When alarmed, schools of longnose dace-swam quickly to shelter or undercut banks and attempted to hide.
Feeding Habits and Food
Schools of age-class 0 longnose dace appeared to feed continually throughout the day. Age-class 0 fish were seen searching in gravel and on rocks for food organisms. Age-class 0 longnose dace were seen feeding on drift. On several occasions they appeared to be searching for invertebrates in the vegetation of runs.
The contents of stomachs from 100 age-class 1 and older longnose dace and from 20 age-class 0 longnose dace were examined. Immature aquatic insects made up 70.5% and insects remains 11.1% of the total volume of food consumed. Vegetation was found in 8% of the stomachs and made up only 2.5% of the total food volume of food. Fish eggs were found in only 2 specimens which were collected in early July. Twenty per cent of the stomachs examined were empty. The stomach contents of age-class 0 fish averaged 2 items per stomach.
Age-class 1 and older fish averaged 3.2 food items per stomach in Sand Creek, and 2.4 in Plarengo River. The composition of the stomach contents was not the same for fish collected in Sand Creek and Marengo River. The difference in the composition of stomach contents of fish collected in Sand Creek and Marengo R. was believed due to the differences in abundance of various aquatic organisms in the two waters. Forage ratios and feeding selectivity were not determined because drift food items in the stomachs could not be distinguished from benthic food items.
The food items consumed by age-class 0 longnose dace were very similar to those consumed by older longnose dace. The main difference was age-class 0 fish consumed the smaller organisms (earlier instars) and older fish the larger organisms. On the basis of observations and stomach samples the longnose dace was considered an insectivorous drift and benthic feeder.
The contribution each food item made to the diet of the longnose dace varied throughout the year. The changes in diet composition, the frequency of occurrence, and per cent contributed by each food item can be seen in Table I. Changes in the composition of the diet were believed to have represented changes in the abundance and availability of food items.
Very little difference between food items utilized and the degree to which they were taken was found in comparison with the findings of Becker (1962), Kuehn (1949). Reed (1959), and Simpson (1941) and the present study. The findings of this study do not support the statement of Simon (1951) and Beckman (1952) that the longnose dace feed to a considerable extent on plant material, algae, and slime.
No surface feeding was observed in Sand Creek., but specimens living in an aquarium fed
at the surface on mosquito larvae. Aquarium specimens also fed on sucker fry. Organisms
which were too large for the longnose dace to swallow were taken into the mouth and then
ejected. Insects in the stomachs were intact and generally not mutilated.
When larger male and female longnose dace approach sexual maturity, both sexes undergo a color change. Their upper and lower lip, breast, and bases of the fins turn red or orange. The females' colors were not as intense as those of the males. Becker (1962) reported finding similar coloration in males and females. Trautman (1957), Sigler and Miller (1963), Simon (1951), and Beckman (1952), mentioned that the males exhibit a color change prior to the spawning period. Sexually mature males were collected from May 17 to July 10. The sexually mature males collected on May 17 and July 10 were only 64 to 67 mm in length. Most of the larger sexually mature males (70-96 mm) were collected from June 10 to July 7. The smaller sexually mature males did not have the red and orange spawning coloration.
No age-class 1 females or males were found to have been sexually mature, but 15 age-class 2 specimens all slowed gonad development in May. Kuehn (1949). Reed (1959), and Becker (1962) reported that longnose dace did not breed until they were two years old. The eggs flowed from ripe females when they were being handled. Ripe females were collected from May 21 through July 11. Spent females were first collected on June 11.
Mixed schools of sexually immature and mature males and females were collected and observed over gravel- bottom runs and in sand-bottom runs during the last week of June and the first week of July when water temperatures were 55 to 63 degrees F. They were believed to be spawning schools., but the actual spawning act was not observed.
Kuehn (1949) reported that the longnose dace spawned from June to August and Becker (1962) reported that they spawned in April and May. Longnose dace were reported as early spawners by Hubbs and Cooper (1936), and spring and early summer spawners by Simon (1951) and Beckman (1962).
The only available description of the breeding behavior of the longnose dace came from Greeley and Bishop (1933), who observed spawning in a small cold stream (55 degrees F) in New York state. They stated that observations were being made on July 16, 1932 when several schools of breeding longnose dace were seen:
Age and Growth
Scales were laid down by the time the longnose dace had grown to 25 mm in length. The scales of specimens 30 mm in length, had 4 circuli.
No scales from longnose dace examined for age in September, 1968 and 1969, and 1978, and October or November, 1968 had more than three annuli, and the fish were ranked in age-classes 0, 1, 2, and 3. Apparently few, if any, longnose dace live longer than through five summers in the study areas.
There was a large amount of overlap in the ranges of lengths of the different age-classes. Reed (1959) reported that the lengths of age-class 1 longnose dace collected in Pennsylvania were 48 to 68 mm, age-class 2 were 64 to 84 mm, age-class 3 were 79 to 92mm, and age-class 4 were 82 to 100 mm. Data obtained from longnose dace collected in October, 1968 and April and May, 1969 indicated that little or no growth occurred after the first of September. Kuehn (1949) reported calculated annual increments in length of 46, 15, 13, and 10 mm for age 1, 2, 3, and 4 longnose dace respectively collected in Minnesota.
None of the scales of longnose dace collected in May showed the new annulus. The new
annulus showed on the scales of 10 specimens collected on July 1. (Copes, 1970)
A general weight-length relationship was calculated for a combined sample of 200 fish collected for Sand Creek on September 4 and 5, 1969. The longnose dace ranged in size from 23 to 116 mm in length and from .2l to 13.3 grams in weight. The weight-length equation was Log W = -19.642 + 2.94 Log L. The correlation coefficient between the weight and length was .99. (Copes, 1970)
Coefficient of Condition
Predation and Disease
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