The effect of raising conditions on behavior of juvenile roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (L.) (Cyprinidae)

The behavior of juvenile 4.5-month-old roach Rutilus rutilus (L.) raised (starting on the 12th day after hatching) at different levels of habitat informational diversity (feeding with live and immobilized zooplankton and benthos, the presence of a predator, and a constant water flow in the nursery aquarium) was studied. The fish’s exploratory behavior and locomotor activity were tested in a circular chamber; swimming activity was tested in a hydrodynamic conduit. It was experimentally shown that juvenile roach raised in the presence of a predator differed significantly (p < 0.05) in regards to behavioral characteristics from the fries raised in a water current and in conditions of a high level of environmental deprivation.     

Growth rate during early life affects sexual differentiation in roach (<Emphasis Type="Italic">Rutilus rutilus</Emphasis>)

Many environmental factors have been shown to influence sex differentiation in fish, resulting in sex-biased populations, but the effects of growth rate have received limited attention. We conducted a controlled laboratory experiment in which growth rate and population density were manipulated in roach (Rutilus rutilus) during early development, and the subsequent effects on sex ratio determined. Significant differences in growth rate between fish populations were induced through provision of three different ration levels. In the slowest growing population there were fewer females compared within the fastest growing population (19% compared to 36% females), suggesting that in roach it may be more advantageous to become a small male than a small female when growth potential is limited. This may result from the fact that fecundity is limited by body size in female roach and that male roach are able to reproduce at a significantly smaller body size than females. In contrast, where roach were kept at different stocking densities, and there were no differences in growth rate, the subsequent proportion of females did not vary. Our data highlight the importance of controlling for growth rate in research on sexual differentiation in this species, notably when assessing for the effects of endocrine disrupting chemicals and other environmental factors, and have implications for fisheries management and aquaculture. The underlying mechanism for the influence of growth rate on sex differentiation has yet to be determined but is likely to have a strong endocrinological basis.     

Morphological Variability of Roach <Emphasis Type=Italic>Rutilus rutilus</Emphasis> (L.) from the Volga Reach of Rybinsk Reservoir

A comparative analysis of literature data and our own results on the morphology of roach from the Volga Reach (Rybinsk Reservoir) in different years is conducted. Recently, (from 2007 to 2010), the morphological characteristics of the roach have been similar to those observed between 1976 and 1978. The roach is characterized by an intermediate position between the herbivorous and malacophagous morphs, but it is more similar to the herbivorous morph.     

Behavioral and morphological asymmetries in roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (Cyprinidae: Cypriniformes) underyearlings

The underyearlings of roach, Rutilus rutilus, displayed a bilateral asymmetry of C-bend—the initial stage of escape behavior. Most individuals exhibited a significant bias to turn leftward or rightward after being stimulated by electrical current. This individual asymmetry was consistent when the same fish were retested ten days later. A significant correlation was revealed between the behavioral asymmetry and the bilateral asymmetry of surface area of frontal (positive correlation) and parietal (negative correlation) cranial bones. No significant correlation was found with the bilateral asymmetry of other morphological characteristics: numbers of pores of the seismosensory canals (praeopercular-mandibular, supraorbital, and supratemporal) in flat cranial bones (dental, praeopercular, frontal, and parietal numbers of lateral line pores, and numbers of rays in pectoral and ventral fins.     

Type of rheoreaction in the early ontogenesis of roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (L.) as a factor determining its biotopic distribution

The specific features of rheoreaction in roach Rutilus rutilus (L.) larvae from open and protected shallows of the Rybinsk Reservoir have been studied. Data on length and weight of roach sampled at various habitats at B–E developmental stages are presented. It has been revealed that the type of roach larvae rheoreaction is a behavioral mechanism of their distribution over different types of habitats, not only in rivers but also in the waterbodies with slow water turnover rates—lakes and reservoirs. By the time of developmental stage E, this mechanism provides the sustainable spatial separation of juvenile fish, which in the future may lead to intrapopulation differentiation in roach.     

Functional state of the liver antioxidant system of the bream <Emphasis Type="Italic">Abramis brama</Emphasis> (L.) from Rybinsk Reservoir regions with different anthropogenic loads

The breams living in five regions of the Rybinsk Reservoir with different degrees of anthropogenic load have been assayed for the characteristics of their antioxidant system (AOS) and lipid peroxidation (LPO) system. Individuals caught at two stations in the Rybinsk Reservoir that maximally differ in the degree of pollution display different qualitative and quantitative compositions of polychlorinated biphenyls (PCBs). At the station at the Sheksninskii Reach, which is located near a local source of pollution (Cherepovets), the total content of PCBs and homologous groups of congeners is one order of magnitude higher than in the bream living at the station of the comparatively clean Molozhskii Reach. The AOS response and the generation intensity of LPO products in the bream (Abramis brama L.) liver caused by different degrees of anthropogenic pollution have been determined. The content of LPO products in the liver of the breams caught in the Sheksninskii Reach is considerably higher and the values of AOS characteristics are considerably lower than in the fish from the Molozhskii Reach. The bream living in the Molozhskii and Volzhskii Reaches are in a more favorable state than those in the Sheksninskii Reach. The AOS and LPO characteristics are an appropriate biomarker for estimating the state of the health of the fish.     

Threshold environmental concentrations of cations defining the range of roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> L. in freshwater reservoirs

Threshold levels of sodium, potassium, calcium, and magnesium that define the distribution range of roach in fresh water are 0.015–0.019, 0.012–0.015, 0.006–0.009, and 0.002–0.003 mmol/L, respectively. A reduction in water mineralization is accompanied by a significant decrease in the concentration gradient of cations between the organism of a fish and the environment and by the increased stress on the systems responsible for salty exchange. Many reservoirs are characterized by lower concentrations of potassium in the water than is needed for the success of the roach population. The survival of roach in these waterbodies depends on the amount of potassium consumed by fish with their food. A comparative analysis is performed to assess the threshold levels of cations for roach, two bivalve mollusk species, crayfish, and the filamentous algae Spirogyra.     

The role of thyroid hormones in the formation of behavioral responses in juvenile roach (<Emphasis Type="Italic">Rutilus rutilus</Emphasis> (L.) (Cyprinidae)

The effect of thyroid hormones (THs) on the formation of behavioral responses in juvenile roach was studied. Eggs taken from one pair of spawners were split into three groups and kept in different environments: a clean water control, with the addition of a hormone, and with the addition of a substance blocking thyroid-gland synthetic activity. It was revealed that control fish and those with an enhanced hormonal status manifest more mature behavior than the fish with a lowered hormonal status.     

High prevalence of zoonotic trematodes in roach (<Emphasis Type="Italic">Rutilus rutilus</Emphasis>) in the Gulf of Finland

The intention to increase roach (Rutilus rutilus) consumption is in focus for ecological and economic reasons in Finland. However, its safety as food has not been considered comprehensively. We collected and artificially digested 85 roach halves originating from the south-eastern coast of Finland, and found trematode metacercariae in 98.8% of the samples. Based on polymerase chain reaction (PCR) and sequencing of amplicons generated from the ITS2 gene region, zoonotic parasites of the family Opistorchiidae were identified as Pseudamphistomum truncatum and Metorchis bilis, and also non-zoonotic Holostephanus dubinini (family Cyathocotylidae) and Posthodiplostomum spp. (family Diplostomidae) were identified. The species identity of other trematodes found is currently being investigated. Mixed infections of several trematode species were common. The prevalence of morphologically identified zoonotic P. truncatum was 46%, and zoonotic M. bilis was found in one sequence sample. The high prevalence of zoonotic trematode metacercariae in roach from the Gulf of Finland is alarming. Only thoroughly cooked roach products can be recommended for human or animal consumption from the area.     

The effectiveness of the induced anti-predator behaviour of zebra mussel <Emphasis Type="Italic">Dreissena polymorpha</Emphasis> in the presence of molluscivorous roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis>

We checked whether the induced anti-predator defences of zebra mussels are able to affect the predation success of roach, being one of the most efficient zebra mussel predators in Europe. Previously, several anti-predator defences of mussels have been observed in the presence of roach, including stronger attachment, aggregation forming and inhibition of upward movement. However, the actual efficiency of these responses to reduce the mussel vulnerability to predation was unknown. To check the effectiveness of attachment strength, we exposed mussels for 6 (strong attachment), 1 (weak attachment) or 0 (unattached) days in ceramic trays and then presented the trays to fish in an experimental tank. To test the effectiveness of aggregation, we glued mussels to the trays in groups of three (touching one another) or singly using denture glue and exposed them to fish. To check the effect of the vertical position, we glued mussels with denture glue to the bottom and 10, 20 and 30 cm above the bottom of the tank with fish. After 1-h exposure, we determined the percentages of consumed mussels. Roach predation rate was lowest on strongly attached mussels, intermediate on weakly attached mussels and highest on unattached mussels. Aggregated mussels were less frequently consumed than singletons. Conversely, the vertical position of mussels did not affect the roach predation success. Our study demonstrates that the behavioural defences exhibited by zebra mussels can increase their survival in the presence of predators and thus emphasizes the importance of the anti-predator behaviour of this species.     

Specific features of thermoregulation behavior in early juveniles of roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> under thermogradient conditions

Specific features of thermoregulation behavior were studied, and values of the selected and final selected temperature (25.1°C) for early juveniles of roach Rutilus rutilus aged 11–28 days after hatching were first studied in long-term experiments (16 days). Two periods of the process of thermoselection—transient (selected temperature, up to 7–9 days after the beginning of the experiment) and final (final selected temperature, 8–10 days after the beginning of the experiment)—have been identified. The selection by larval roach of final selected temperature values occurs with use of the adaptation response of “excessive responding.” It was shown that correct determination of final selected temperature values for early juveniles of fish is possible only in long-term experiments (more than 7 days). The obtained results can be used during the analysis of behavior and distribution of larval roach under natural and experimental conditions.     

Comparative analysis of generative parameters of the roach <Emphasis Type=Italic>Rutilus rutilus</Emphasis> (L., 1758) in the Volga reach of the Rybinsk Reservoir

An analysis of the reproductive potential of roach in the Volga reach of the Rybinsk Reservoir is made on the basis of published data and our own data obtained from 1953 to 2012. Values of fecundity obtained in the 2000s are the most similar to the results of 1976. Parameters of the intensity of the generative exchange of females (absolute and relative fecundity and size and mass of eggs) were high in 2007 and 2012, which indicates a sufficient food supply, especially of medium and large roach.     

The structure of <Emphasis Type="Italic">Dreissena polymorpha</Emphasis> (Pallas) biocenosis and the role of mollusk in roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (Linnaeus) feeding in Pleshcheevo Lake

As a result of studies on the macrozoobenthos composition of zebra mussel biocenosis in Lake Pleshcheevo carried out in 1996, a total of 44 species of bottom macroinvertebrates were found. The richest in terms of species composition were chironomids (17 species), oligochaetes (13 species), and mollusks and leeches (5 species each). After the introduction of zebra mussel Dreissena polymorpha (Pallas) into the lake, a natural biophilter was formed in the waterbody at depths of 4.5 to 9 m. This biophilter intercepts a substantial part of degrading macrophytes and allochtonous organic matter. Thus, the filter prevents the income of this organic matter in the lake’s profundal zone. Two roach Rutilus rutilus (Linnaeus) groups had inhabited Lake Pleshcheevo before dreissena introduction. Comparatively fast growing roach fed predominantly on mollusks of g. g. Valvata and Bithynia, while slowly growing roach fed mostly on zooplankton. After the introduction and mass development of D. polymorpha in the lake, roach started to consume these mollusks. This resulted in increases in the fish growth rate and maximum body size. Roach starts to feed on dreissena and other mollusks after reaching a body length of 15.0 cm. This relates to the third and the last change in the pharyngeal teeth shape, making possible for the fish to consume mollusks and to crush their shells.     

Impact of heron (<Emphasis Type="Italic">Ardea cinerea</Emphasis> L. and <Emphasis Type="Italic">A. alba</Emphasis> L.) habitat on coastal juvenile fish assemblages in Rybinsk Reservoir

It has been determined that the stocking density of juvenile fish in an open reservoir shallow-water site in the heronry area in the nesting period is higher than that in the reference site. The juvenile roach Rutilus rutilus L., which is one of the dominant species, in the bird impact zone significantly differs in higher values for both the size–weight characteristics and the body weight-growth rates. The habitat-dependent phenotypic differences in various biotopic assemblages of the juvenile fish are revealed. It has been proven that the environmental impact of the heron-colony life activities on the fish populations in the reservoir shallow-water site is temporary, which is limited by the bird-nesting season.     

Variability in development of bilateral parts of the brain during ontogenesis of roach (<Emphasis Type="Italic">Rutilus rutilus</Emphasis>)

A study exploiting the gravimetric method did not reveal identical development of paired parts of the roach (Rutilus rutilus) brain. In the studied sample, the proportion of fish with left or right asymmetry of this organ was 1: 1. The specificity of fluctuating asymmetry in studied plastic parameter depending on the fish age and growth was analyzed. In the ontogenetic sequence, from yearlings to nine-year-old fishes, the higher level of developmental instability was revealed in elder fish, six and more years old. Noted anatomical-morphological feature is likely determined by not only imperfect morphogenesis during early development: potential decrease in the threshold of noise immunity against unfavorable external and internal factors during later stages of fish development may contribute to the feature noted above. The analysis of sex-related traits revealed that in males fluctuating asymmetry of the brain bilateral parts is more pronounced.     

Mobility of individual roach <Emphasis Type=Italic>Rutilus rutilus</Emphasis> (L.) in three weir-fragmented Belgian rivers

Adult roach Rutilus rutilus (L.) (N = 24; 19.9–36.1 cm FL) from three highly fragmented Belgian rivers were tagged with surgically implanted radio transmitters. Their seasonal movements were observed from March to August 2004 (circum reproduction period) in river stretches delimited by two physical barriers. In the three rivers, roach displayed similar patterns of movements which were mainly influenced by the date of observation (movements increased in late April–May) and water temperature (travel distances were more important when water temperature ranged between 10°C and 14°C). Roach sometimes cleared physical obstacles. The mean distances travelled in each river were relatively short (max. 2.5 km) and mainly influenced by the length of the study reach, which was delimited by physical barriers.     

Exploratory behavior of juvenile roach <Emphasis Type="Italic">Rutilus rutilus</Emphasis> (L.) (Teleostei: Cyprinidae) in a maze after different magnetic impacts on embryos

We have investigated a sequence of visits to arms in a cross maze in juvenile (1-year-old) roach Rutilus rutilus (L.). Fish embryos of one group are raised under a natural geomagnetic field. The embryos of another group are exposed to the main phase of a simulated geomagnetic storm (changes in geomagnetic field up to 100 nT for each component). It turns out that the sequence of visits does not differ from random in both groups. Thus, the exploratory behavior in juvenile roach differs from other animal taxa investigated earlier. In the latter taxa a spontaneous alternation was observed: a tendency to visit the arm which was visited least recently.     

Biolistic transformation of cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.) with the <Emphasis Type="Italic">phyA</Emphasis> gene from <Emphasis Type="Italic">Aspergillus ficuum</Emphasis>

Transgenic cotton with an increased level of phytase activity was generated from cotton (Gossypium hirsutum L.) cv. ND94-7 by subjecting shoot-apex explants to particle bombardment. These tissues were transformed with plasmid pC-KSA2300 carrying a selectable marker (for kanamycin) and a target gene (phytase, or phyA, from Aspergillus ficuum). Primary plants were regenerated in a medium containing 75 mg l⁻¹ kanamycin. Of 1,534 shoot apices, 52 (3.4%) survived on this selection medium. Southern and Northern blot analyses confirmed that phyA was stably integrated and expressed in those primary transgenics. The progenies of the primary transgenic plants were found to have a 3.1- to 3.2-fold increase in root extracellular phytase activity, resulting in improved phosphorus (P) nutrition. Growth also was enhanced when they were supplied with phytate, and their P content was equivalent to that of wildtype plants supplied with inorganic phosphate. These results demonstrate that the expression of phyA in cotton plants improves their ability to utilize organic P in response to a deficiency.     

<Emphasis Type="Italic">Agrobacterium-</Emphasis>mediated transformation of gypsophila (<Emphasis Type="Italic">Gypsophila paniculata</Emphasis> L.)

As a major contributor to the flower market, Gypsophila paniculata is an important target for the breeding of new varieties. However, gypsophila breeding is strongly hampered by the sterility of this species’ genotypes and the lack of a genetic-transformation procedure for this genus. Here we describe the establishment of a transformation procedure for gypsophila (Gypsophila paniculata L.) based on Agrobacterium inoculation of highly regenerative stem segments. The transformation procedure employs stem explants derived from GA₃-pretreated mother plants and a two-step selection scheme. The GA₃ treatment was crucial for obtaining high gene-transfer frequencies (75–90% GUS-expressing explants out of total inoculated explants), as shown using three different gypsophila varieties. An overall transformation efficiency of five GUS-expressing shoots per 100 stem explants was demonstrated for cv. Arbel. The applicability of the transformation system to gypsophila was further reinforced by the generation of transgenic plants expressing Agrobacterium rhizogenes rolC driven by a CaMV 35S promoter. Transgenic gypsophila plantlets exhibited extensive rooting and branching, traits that could be beneficial to the ornamental industry.