The relationship between foraging and shoal position in a mixed shoal of roach (Rutilus rutilus) and chub (Leuciscus cephalus): a field study

Dactylogyrid species (Monogenea) communities were studied in roach, Rutilus rutilus, collected from two localities in the basin of Morava river, Czech Republic, during the period from April to November 1997 and March to September 1998 to determine the effect of water temperature on parasite abundance, species richness and diversity. Dactylogyrid species were found to co-occur on the gills of roach with up to six species found on the same host individual. Nine dactylogyrid species were identified with the abundance of each reaching a very low level. Niche size was considered to increase with species abundance even when water temperature was high. There was a strong effect of water temperature on abundance of the common dactylogyrid species (D. crucifer, D. nanus, D. rutili and D. suecicus) as well as of the rare species D. rarissimus. The temporary occurrence of the rare species was found without any temperature effect. Water temperature did not affect the relationship between abundance and niche size. Niche size increased with abundance, even when the water temperature was high, which suggests that negative interspecific interactions are not important within dactylogyrid communities.

Download Full-text

Fecundity of Two Cyprinid Fishes in the River Thames, Reading, England

Journal of the Fisheries Research Board of Canada ◽

10.1139/f69-276 ◽

1969 ◽

Vol 26 (11) ◽

pp. 2795-2805 ◽

Cited By ~ 42

Author(s):

I. Mackay ◽

K. H. Mann

Keyword(s):

Population Density ◽

Egg Production ◽

Rutilus Rutilus ◽

Confidence Limits ◽

Roach Rutilus Rutilus ◽

Spawning Period ◽

Cyprinid Fishes ◽

River Thames ◽

The Relationship ◽

Bleak Alburnus Alburnus

Egg production by two cyprinids in the River Thames at Reading, England, was studied quantitatively from January to June 1966. Roach (Rutilus rutilus) had a short spawning period, shedding all their eggs in one batch, whereas bleak (Alburnus alburnus) had a protracted spawning period and produced two or three batches of eggs. The relationship between egg numbers (Y) and age (X) for roach was given by log Y = 0.0840X + 3.2085; the estimated fecundity of a 6-year-old fish was 5157 with 95% confidence limits at 4725 and 5631. For bleak the relationship was log Y = 0.0564X + 3.5221, and the estimated fecundity of a 5-year-old fish was 6356 with 95% confidence limits at 5987 and 6776. Combining previously obtained data on population density with new data on sex ratio and percentage breeding in each age class, the population fecundity for roach was about 600 eggs/m2 and for bleak about 3000 eggs/m2.The roach population had lower fecundity than roach populations in other studies and there was some evidence that a proportion of females ceased egg production during the period of the study. The possibility that low fecundity was a response to food shortage is discussed.

Download Full-text

The fine structure of muscle fibres of roach, Rutilus rutilus (L.), and chub, Leuciscus cephalus (L.), Cyprinidae, Teleostei: interspecific differences and effects of habitat and season

Journal of Fish Biology ◽

10.1111/j.1095-8649.1990.tb05596.x ◽

1990 ◽

Vol 36 (2) ◽

pp. 205-213 ◽

Cited By ~ 21

Author(s):

A. M. Sanger ◽

Z. S. Kim ◽

H. Adam

Keyword(s):

Fine Structure ◽

Rutilus Rutilus ◽

Muscle Fibres ◽

Roach Rutilus Rutilus ◽

Interspecific Differences ◽

Leuciscus Cephalus

Download Full-text

Genetic structure and differentiation among populations of two cyprinids, Leuciscus cephalus and Rutilus rutilus, in a large European river

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f99-100 ◽

1999 ◽

Vol 56 (9) ◽

pp. 1659-1667 ◽

Cited By ~ 10

Author(s):

J Laroche ◽

J D Durand ◽

Y Bouvet ◽

B Guinand ◽

B Brohon

Keyword(s):

Isolation By Distance ◽

Geographic Distance ◽

River System ◽

Rutilus Rutilus ◽

Genetic Distances ◽

Roach Rutilus Rutilus ◽

Variable Environment ◽

Environmental Diversity ◽

Historical Factors ◽

Leuciscus Cephalus

The aim of this investigation was to compare the genetic responses of two common cyprinids, chub (Leuciscus cephalus) and roach (Rutilus rutilus), to various habitat and pollution regimes within the same river basin, the Rhone, using allozyme data. Over the three main portions of the River Rhone, lower genetic polymorphism and lower heterozygosity were detected for the chub in the Saone, which is characterized by lower environmental diversity than in the Lower and Upper Rhone. On a local scale, no detectable decrease in polymorphism or heterozygosity was observed in populations of both species living in heavily polluted sites of the Rhone's Chemical Corridor. Significant differentiation was detected between populations of both chub and roach localized upstream and downstream from the dams of Donzère Mondragon, which were erected 45 years ago. The F statistics and neighbor-joining analysis of genetic distances suggested that the Upper Rhone populations were unique in comparison with the other populations for both species; this situation could be the result of historical factors and (or) a selective pressure in a variable environment. Isolation by distance was observed for chub in the less perturbed river system over a range of 100 km. By contrast, there was no relationship between geographic distance and genetic distance for roach, whatever the subsystem tested.

Download Full-text