Using three different swimming velocities and a school size of eight roach Rutilus rutilus, individual intra-school position and tail beat frequency were examined in a flume tank. Tail beat frequency was determined in defined leading and trailing positions. Individual roach showed consistent intra-school positional preferences which implied a sustained positional pattern where certain individua...

A model that assesses risks posed by feminization to wild populations of roach was developed. A population life table matrix model that considered both sexes and a newly developed fertility kinetic function was applied to calculate the intrinsic population growth rate (lambda) of roach populations where males had been feminized. The maximum sustainable yield (MSY) was used to quantify the effec...

the research was accomplished in order to study behavioral and histopathological effects of copper on rutilus rutilus caspicus under experimental condition. the study was performed using water static method during 96 hours. 15 fish with averaged weight 2?0.5 g in weight were encountered to different concentrations (0, 0.1, 0.2, 0.3, 0.4 mg/l) of copper. a group of fish was considered as control...

skeletal deformities are a common problem in fish hatcheries and commercial farms that affect growth, development and survival as well as the market value of the final product. among the nutritional components, phosphorus (p) and calcium (ca) are of special interest as they are directly involved in the development and maintenance of the skeletal system. hence, the present study was carried out ...

Roach (Rutilus rutilus) and perch (Perca fluviatilis) are dominant species in northern-temperate lakes of Europe, their relative importance depending on trophic state habitat complexity. We studied the distribution roach over a 15-year period two Danish lakes, Lake Væng, undergoing major changes water clarity macrophyte coverage, permanent turbid Søbygård. used multi-mesh sized gill nets 5-6 di...

Population-ecological analysis of Aral roach ( Rutilus rutilus aralensis ) was conducted in Tuzkan lake Aydar-Arnasay system Uzbekistan. In the system, it analyzed age structure, body weight, 19 morphometric and 5 meristematic indicators 158 fish specimens caught Lake January February 2020. The main selected as a result statistical are: arithmetic mean; error rate; variability morpho-physiologi...

According to the immunocompetence handicap hypothesis, males with attractive sexual ornamentation are more handicapped than their less ornamented rivals because of the immunosuppressive androgens required for the production of secondary sexual characters. Here we studied the predictions of the hypothesis in a wild cyprinid fish, the roach (Rutilus rutilus). We assayed (1) sexual ornamentation (...