Intensive Rearing of Young Roach (Rutilus rutilus (L.)) at 20°C

A re-circulating system was used to examine the growth of two groups of young roach at an above ambient temperature of 20°C. An artificial diet was developed on which fish of one summer grew from 1.0 to 6.9 g over a 4.5 month winter period. Partial gonad development and the decrease in food intake to 1% body weight per day amongst fish of greater than 30 g were found to be serious limitations to growth. Parasitic diseases were readily controlled but the appearance of chronic kidney disease remains unexplained.     

The Spawning of Roach Rutilus rutilus (L.) in a Chalk Stream

Roach spawned on two sites where Fontinalis antipyretica (Hedw.) grew thickly on vertical pilings. The eggs were distributed throughout the fronds of Fontinalis but were concentrated near the water surface. The fish spawned on those parts of the sites where the current adjacent to the weed was relatively fast. The sudden drop in water levels caused by weed cutting presents a potential threat to spawning success.     

The Induced Spawning and Subsequent Survival and Growth of Roach Rutilus rutilus (L.)

The spawning of roach on artificial substrate using pituitary injection is described. The sur vival and growth of these fish is compared with fish taken from a natural environment. Sur vival is found to be as good as the natural fish provided an adequate initial size is reached before stocking.     

Susceptibility of Caspian Roach (Rutilus rutilus caspicus) Fingerlings to Formalin

ABSTRACT

Caspian roach (Rutilus rutilus caspicus) were exposed to 0, 30, 40, 45, 50, 55, 60, 70, 100, 150 200, 250, 300, and 400 ppm formalin to determine LC₅₀. Respectively, 0.5 to 96 h LC₅₀ values were 252 to 49 ppm. The lowest observed effect concentrations (LOEC) and no observed effect concentrations (NOEC) varied between 40 to 150 and 30 to 100 ppm, respectively, across the tested time spectrum. Regression suggested that the concentrations of 88.4, 80.3, 51.2, and 40.1 ppm are maximum concentrations for 0.5, 1, 12, and 24 h bath treatment, respectively, which are not in the range suggested in the literature.     

Progestogen metabolism by ovaries of the roach (Rutilus rutilus L.) and the rudd (Scardinius erythrophthalmus L.)

Roach ovaries converted 17-hydroxyprogesterone to 17,20-dihydroxy-4-pregnen-3-one (17,20P) and to glucuronides of testosterone and 17,20P. Small amounts of 5-pregnane-3- and -3, 17, 20-triols, 7-hydroxy-5-reduced metabolites and 17,20-dihydroxy-4-pregnen-3-one (17,20P) were also formed. Rudd ovaries converted this substrate mainly to 17,20P, 5-pregnane-3- and -3,17,20-triols, 17,20-dihydroxy-5-pregnan-3-one and testosterone glucuronide. The main metabolites of progesterone with both species were 17,20P, 5-pregnane-3,17,20-triol and 7-hydroxy-5-reduced steroids. Rudd ovaries formed, in addition, 17,20-dihydroxy-5-pregnan-3-one from progesterone. The pattern of metabolites was markedly altered when the concentration of substrate was increased from 42ng to 1 µg or 100 µg. At the highest concentration, glucuronides and polar steroids were not detectable, while at low concentrations they accounted for over 50% of the metabolites. 20-Hydroxysteroid dehydrogenase was shown to have a very high capacity, producing 21–47 µg 17,20P from 100 µg 17-hydroxyprogesterone substrate with 200 mg ovarian tissue in 5h.     

Isolation and structural characterization of hepatic metallothionein from the roach (shape Rutilus rutilus L.)

Metallothioneins (MTs), considered as metal biomarkers by many authors, are very conserved proteins that present great interests in phylogenetical studies. This paper reports the purification of the hepatic MT from the roach (Rutilus rutilus). After extensive reverse-phase HPLC, the sequence of the MT was established by a combination of techniques including automated Edman degradation, mass spectrometry and enzymatic treatment. Sequence comparison with other fishes or mammalian MTs showed considerable identities and a high conservation in cysteine residues positions. MTs of roach and goldfish that both belong to the same family (Cyprinidae) share 97% identity. Ninety five% identity were found between roach and stone loach (Cypriniforms, Cobitidae) MTs. Only 77% identity were found with pleuronectiforms or salmoniforms. This sequence brings a new element in the study of the phylogenetical relationships among teleost species.     

Factors affecting between-lake variation in the occurrence of epidermal papillomatosis in roach, Rutilus rutilus (L.)

The theory of island biogeography predicts that the probability of a species occupying an island depends on a dynamic equilibrium between extinction and colonization. Epidermal papillomatosis is a disease manifesting as skin tumours on fish. We studied the factors affecting the occurrence of the disease in roach, Rutilus rutilus (L.), in 34 lakes. The results of discrimination analysis suggest that maximum depth, percentage of the drainage area of the lake covered by lakes in the vicinity and altitude best identified diseased lakes. Comparison of diseased and non-diseased lakes revealed that lake area could also be regarded as a variable contributing to the occurrence of the disease. The sampling date, proportion of males and mean length of fish did not discriminate between the lakes. The probability of the disease occurring was highest in large, deep, low-altitude lakes which had a high percentage of lakes in their vicinity. Thus, the results indicate that the colonization and extinction processes probably contribute to the occurrence of papillomatosis in roach, as predicted by the theory. Furthermore, the large natural variation in the occurrence of the disease could mask possible environmental effects and between-lake comparisons should be interpreted with caution when using the fish-papillomatosis system as an indicator of environmental stress.     

Seasonal variation in the habitat available for 0+ Rutilus rutilus (L.) in a regulated river

1. Habitat availability for 0+ Rutilus rutilus (L.) was determined at four sites in the regulated River Great Ouse, Eastern England, using a modified version of the Instream Flow Incremental Methodology. Discharge–habitat relationships were then calculated using a modified version of the Physical Habitat Simulation (PHABSIM) computer package. A weighted usable area (WUA) time series was generated using the discharge–habitat models. 2. Habitat availability varied between sites and with discharge, although at three of the four sites some suitable habitat remained throughout the year. In general, more habitat was available for juvenile fishes than for young larval fishes and during the winter. 3. As discharge increased habitat availability decreased, primarily as a result of increased velocity and depth. This was exacerbated by the trapezoidal shape of the main channel. In a marina, which was thought to be acting as a flood refuge, WUA decreased as a result of increasing water depth. Only in a modified backwater did WUA increase with discharge. Owing to the morphology of the backwater, there was still a WUA minimum at intermediate discharges. 4. The output of the model indicates the variation in habitat available for small fish in both temporal and spatial dimensions, and reinforces the requirement for spatial heterogeneity in riverine habitats for the preservation of fish stocks. © 1997 John Wiley & Sons, Ltd.     

布伦托海湖拟鲤的生物学研究

布伦托海位于新疆北部的福海县境内 ,为乌伦古河流域容浅区 ,总面积达 140多万亩。平均水深7～ 8米。湖周多戈壁、沙漠、气候干燥 ,蒸发量大于降水量的 15倍以上。昼夜与周年的温度交差均较大 ,夏季极端最高所温为 39 2℃ ( 1974年 ) ,冬季极端最低气温 - 4 1 2℃ ( 1972年 )冰封期长达四个半月至五个月。湖拟鲤 (Ｒｕｔｉｌｕｓｒｕｔｉｌｕｓｌａｃｕｓｔｒｉｓ (Ｐａｌｌａｓ)为中小型经济鱼类 ,在我国原仅分布于新疆北中额尔齐斯河流域。 1966年人工移植到布伦托海 ,1971年开凿了沟通布伦托海与额尔齐斯河的“引额济海渠道”后 ,湖拟鲤…     

Parasitism, condition and number of front head breeding tubercles in roach (Rutilus rutilus L.)

Abstract –  In a previous study on the male roach, Rutilus rutilus , we found a positive correlation between sexual ornamentation, breeding tubercles (BTs) on lateral sides and parasite resistance. As a continuation of that study, we examined another measure of sexual ornamentation – number of BTs on front head – of male roach from five populations. BTs on head correlated positively with fish size in two populations and with condition in one population, but not with parasite resistance (proportion of dead parasites) in any of the populations. Moreover, head BTs correlated negatively with the number of two parasite species ( Rhipidocotyle campanula and Myxobolus mülleri ) in two populations, but positively with the number of a third parasite ( Raphidascarus acus ) in one population. In addition, a negative correlation with spleen size was found in one population. The present results suggest that head BTs of male roach – although the patterns vary between populations – may signal condition and parasite load, but not resistance, in contrast to lateral BTs. Therefore, our results are in line with the hypothesis of multiple-message sexual ornaments.     

Effects of Different Dietary Lipid Sources on Growth Performance,Salinity Tolerance,Haematological and Biochemical Parameters of Caspian Roach (Rutilus rutilus caspicus) Juvenile

This study investigates the effects of replacing fish oil with two vegetable oils (Sunflower oil and Soybean oil) on growth performance, salinity tolerance, hematological and serum biochemical profile of Rutilus rutilus over 56 days. Five diets were supplemented with 8% of either fish oil (FO) (control), sunflower oil (SFO), and soybean oil (SO) or a combination of 4% FO with 4% SFO and 4% FO with 4% SO, respectively. Triplicate groups of fish (24 fish per tank with an average body weight, of 5.52 g) were assigned to each diet. Blood samples were taken from the caudal vein of 75 apparently healthy fish at the end of trial. Hematological values of the blood samples were determined using standard techniques. At the end of the experiment fish were exposed to salinity stress. The results showed that the best growth performance was in fish fed the control diet, but the differences were minor among treatments containing vegetable oils (P > 0.05). Serum cholesterol and glucose concentrations were significantly higher in fish fed dieta containing vegetable oils (P < 0.05). Red blood cell count (RBC), hematocrit (Ht) and hemoglobin (Hb) in groups fed diets containing SFO and SO were higher than other groups (P < 0.05). There was no significant difference in survival after 48 h salinity stress (P > 0.05). These results indicate that in cases where fish oil is scarce or expensive, vegetable lipids can be used as replacements without any serious negative growth performance and health impacts.     

The significance of myxosporean infections in roach, Rutilus rutilus L., in different habitats

Abstract. Two Myxobolus species, M. pseudodispar and M. ellipsoides , and two Myxidium species, M. rhodei and M. pfeifferi , were found in roach, Rutilus rutilus L., from three different locations in northern Greece, northern England and Scotland. Their prevalence, distribution in the host and pathology were studied. In the ease of M. rhodei , the pathological changes were quantitatively evaluated by computer-based image analysis, and the results expressed in terms of area and volume of organs affected. The pathology of M. pfeifferi was associated with trophozoites in the bile duets and the infection ranged from mild to severe. In the severe eases, degeneration of duetal mucosa sometimes progressed to focal hepatitis. Myxidium rhodei was found in the kidneys as large cysts containing mature and immature spores (Type A cysts), and less often, in the form of small concentric cysts (Type B) which contained no obvious spores but which were characterized by a marked host response giving the appearance of focal granulomas. Type A cysts were also found in liver and spleen, and Type B cysts in the heart. Trophozoites of M. rhodei were observed in only a few eases and occurred in enlarged renal corpuscles in which the capillary tuft was atrophied and compressed. The pathology of M. rhodei was significant due to the enlargement of glomeruli from four to seven times their normal size and with an estimated increase in volume of 54 to 78 times. In addition to the functional damage to the glomeruli, there was also damage of the surrounding interstitial tissue and tubules as a result of the pressure from these enlarged glomeruli. The two myxobolid species were considered to be mainly specific to the kidney with no serious pathology in this organ, but caused significant pathology in the muscles ( M. pseudodispar ) and gills ( M. ellipsoides ).     

The differential effects of Ligula intestinalis (L.) plerocercoids on host growth in three natural populations of roach, Rutilus rutilus (L.)

Abstract – This study reports the differential effect of the pseudophyllidean cestode, Ligula intestinalis , on the growth rates of three fish populations of the roach, Rutilus rutilus , under field conditions. Here, we show that only one host-population is affected by parasite-induced gigantism in the first 2 years of host life. Paradoxically, this increase in fish growth is strongly correlated with the parasitic load in plerocercoid stages, in that only the roach population subjected to the heaviest parasitic pressure shows an enhanced growth of cestode-parasitized individuals. This host gigantism observed in only one locality is associated with parasite-induced fish mortality occurring, on average, one year earlier in this fish population when compared to other populations. We discuss the different reasons for this differential parasite effect on growth enhancement across host-population in natural settings. Whether the growth effects represent an adaptive response by the host or a manipulation by L. intestinalis of the host, remains to be elucidated.     

Factors affecting the intensity of epidermal papillomatosis in populations of roach, Rutilus rutilus (L.), estimated as scale coverage

Studies of epidermal papillomatosis in fish populations have only rarely focused on the intensity of the disease, i.e. the number and size of papillomas. Furthermore, the methods used to evaluate the intensity of papillomatosis have not been standardized. We tested the reliability of a method based on counting of scales covered by papilloma tumours in roach, Rutilus rutilus (L). In addition, we studied the frequency distributions of the number of scales covered by papillomas within populations, evaluated the correlation between the prevalence and mean intensity of the disease among populations and examined the intensity of papillomatosis in roach with respect to sex and size of fish. Reliability of the scale coverage method was high. Therefore, the method could offer an effective way to determine the intensity of papillomatosis in fish species with large scales. The frequency distribution of the scale coverage of papillomas was highly aggregated within all populations studied. The mean intensity of papillomatosis increased with the size of the fish and was higher in males than in females. However, there was no correlation between the mean intensity and prevalence of the disease among the 19 roach populations studied.     

Eimeria branchiphila sp.nov. sporulating in the gill filaments of roach, Rutilus rutilus L.

Abstract. Eimeria branchiphila sp. nov. is described from the roach, Rutilus rutilus L., collected in Bulgaria. Sporulated oocysts were found in gill secondary lamellae and less frequently were associated with melano-macrophage centres in the spleen and in kidney interstitial tissue. In the gills, parasite cells identified as zygotes and sporulation stages were also encountered. This unusual site of sporulation represents a mechanism of sporocyst dispersal previously not recorded in fish coccidia.     

Eimeria scardinii Pellérdy and Molnár, 1968 in the kidneys of Rutilus rutilus (L,) and Scardinius erythrophthalmus (L.) from northern Greece

Abstract. The occurrence of Eimeria scardinii in roach, Rutilus rutilus (L.), and rudd, Scardinius erythrophthalmus (L.), from a lake in northern Greece is reported. The coccidium was found in the renal haemopoiettc tissue, mainly in the form of mature sporulated oocysts. The morphology and dimensions of the parasite, as well as the host reaction, were very similar in both species of fish examined. The overall prevalence of infection in roach and rudd was 6·67% and 6·3%, respectively. The prevalence of infection of roach was higher during summer (22·22%) but less than 5% in other seasons.     

Some observations of spawning by roach, Rutilus rutilus L., and bream, Abramis brama L., and their implications for management

Abstract. The spawning behaviour of roach, Rutilus rutilus L., and the spawning of roach with bream, Abramis brama L., is described with details of the nature of the spawning ground used at two sites in mid-west Britain. Roach appear to use traditional spawning grounds annually. Some female roach probably die as a result of damage inflicted by males during spawning. A simple exponential model is used to describe the relationship between temperature and the incubation period of roach eggs.     

Genetic analysis of Rutilus rutilus caspicus (Jakowlew 1870) populations in Iran by microsatellite markers

The Caspian roach (Rutilus rutilus caspicus) is regarded as one of the most important commercial species in the Caspian Sea. Despite the commercial and conservation importance of the species, information on genetic relationships and diversities at the molecular level in Rutilus rutilus caspicus is scarce. Six microsatellite loci were analysed to study the genetic variation in two major populations of Caspian roach in the Iranian waters of the Caspian Sea: the Anzali Wetland and Gorgan Bay. The F_st value between populations was 0.07, suggesting that the genetic differentiation was significant (P<0.01). Both the studied populations deviated from Hardy–Weinberg equilibrium proportions at a number of loci, mostly due to the deficiency of heterozygosities. The genetic distance between populations was 0.29, which indicates that the genetic difference among the studied populations is pronounced. The differences between both populations were not statistically significant (P>0.05), neither for average number of alleles per locus nor for observed heterozygosities. The data generated in this study provide useful information on the genetic variation and differentiation in populations of Caspian roach.