Female Perch Research Articles

DNA adducts and histopathological lesions in perch (Perca fluviatilis) and northern pike (Esox lucius) along a polycyclic aromatic hydrocarbon gradient on the Swedish coastline of the Baltic Sea

DNA adducts, histopathological abnormalities, and organosomatic indices were used to study contaminant effects on fish along a polycyclic aromatic hydrocarbon (PAH) gradient, leading away from an aluminum smelter on the Swedish Baltic coast. The level of DNA adducts, analysed using the 32P-postlabelling method, was at least 145 times higher in the liver of female perch (Perca fluviatilis) from the innermost site on the gradient, closest to the suspected point source of PAHs, than at a distant reference site. Of the DNA adducts analysed, a relatively small number accounted for a very high proportion of the total level of adducts (30-60% at the innermost site and close to 100% at the outermost site). These particular adducts could also be observed in extrahepatic tissues, such as trunk kidney and head kidney, along the entire gradient. Similar patterns of adducts were also observed in northern pike (Esox lucius). Focal hepatocellular degeneration in perch was about 15 times more extensive at the innermost site than at the next site in the gradient and absent in perch from the two outermost sites. Body size relative to age was also significantly reduced in perch from the three innermost sites compared with the outermost site.

Effects of ECF-Bleached Kraft Mill Effluent on Reproductive Steroids and Liver MFO Activity in Populations of Perch and Roach

Samples of perch (Perca fluviatilis L.) and roach (Rutilus rutilus L.) populations were collected in Lake Saimaa in September-October, after the onset of vitellogenesis and deposition of yolk in the eggs. The study area received elemental chlorine-free (ECF)-bleached kraft mill effluent (BKME). The pulp and paper mill studied used chlorine dioxide for bleaching and its effluents were treated in a modern activated sludge plant. The amounts of chlorophenolics in the bile of perch and roach at the mill site, 1 km from the discharge point, were two to four times higher than in fish from the upstream reference site. In the roach population near the mill liver the 7-ethoxyresorufin 0-deethylase (EROD) activity was four times that measured in the reference areas. However, the EROD activity in the perch remained unchanged. The liver 7-pentoxyresorufin 0-dealkylase (PROD) activity was induced to twice the amount only in male roach near the mill, whereas the relative liver size (LSI) was increased in female and male roach and female perch. The plasma concentrations of oestradiol-17β were decreased in female perch and female roach, but increased in male roach at the mill site. Near the mill, vitellogenin gene expression was also reduced in female perch. In addition, the plasma testosterone concentrations were reduced in female and male perch near the mill. No differences were noted in the plasma immunoglobulin concentrations in roach and in the relative gonad size (GSI) in the perch and roach populations. The condition factor was significantly lower only in female roach near the mill.

Influence of feeding level on growth, intraspecific weight variability and sexual growth dimorphism of Eurasian perch Perca fluviatilis L. reared in a recirculation system

The influence of the feeding level (FL) on growth and sexual growth dimorphism, was investigated in juvenile Eurasian perch (10 g initial body weight) reared in a recirculation system over 84 days. Fish were divided into groups of 105 individuals and fed three feeding levels: 1, 2 and 3% of the fish biomass (3 replicates/FL). Survival was not significantly ( P > 0.05) different among the three FLs. Feeding levels significantly affected ( P < 0.05) growth performance of perch; mean body weight at the end of the experiment was 22.3 ± 0.5 g, 47.9 ± 2.4 g and 52.7 ± 1.7 g, at 1, 2 and 3% FL, respectively. Significant differences were observed among the specific growth rate of fish fed at 1, 2 and 3% FL. Similar feed conversion ratios (FCR) were obtained for fish fed at 1 and 2% FL (1.08 and 1.01, respectively) which were significantly lower ( P < 0.05) than that obtained for the groups fed at 3% FL (1.53). Weight heterogeneity was significantly affected by feeding level. During the 84 days, the coefficient of variation (CV) for weight decreased from 45–50% to 30–35% when perch received the 1 or 2% FL. On the other hand, CV remained constant at the 3% FL. The final autopsy of perch revealed that a 3% FL favoured a sexual growth dimorphism. While no significant weight differences between male and female perch were recorded in fish fed at 1 or 2% FL, the 3% FL females were larger than their male homologues (59.2 ± 1.2 vs. 47.6 ± 3.1, P < 0.01). These data suggest that feeding management could be used to regulate weight heterogeneity and sexual growth dimorphism in perch culture.

Frequency distributions of fish parasites in the perch Perca fluviatilis L. from Lake Constance.

Seventy perch (Perca fluviatilis) caught in Lake Constance at Langenargen in May 1990 were examined for parasites. The frequency distributions of the eyefluke Diplostomum spathaceum (Rudolphi, 1819), and the tapeworms Proteocephalus percae (Müller, 1780) and Triaenophorus nodulosus (Pallas, 1781) fitted closely to a negative binomial. Only a few fish were highly parasitized. These fishes are devoured by the final hosts: gulls (Diplostomum spathaceum) or the pike (Triaenophorus nodulosus). The fish population was influenced negligibly and the parasite population stayed at a moderate level. During the spawning period female perch were infested with Proteocephalus percae more than the males. This may be because the females had a higher food consumption and became more infected by copepods (intermediate hosts). In contrast, Diplostomum spathaceum, Ichthyocotylurus variegatus, Triaenophorus nodulosus, and Tylodelphys clavata did not occur in different numbers in female and male perches. The frequency distribution of Ichthyocotylurus variegatus (Creplin, 1825) and Tylodelphys clavata (Nordmann, 1832) did not conform to a negative binomial.

Baseline studies of biomarkers in the feral female perch ( Perca fluviatilis) as tools in biological monitoring of anthropogenic substances

Since 1988, yearly measurements of several physiological and biochemical variables have been performed using feral female perch ( Perca fluviatilis) from an assumed reference area in the Baltic proper, Kvädöfjärden. The area is divided into two stations, Meta and Häxvassen, approximately 20 km apart. Standardized sampling and measurements have shown that a number of variables such as somatic body weight, total length, gonadosomatic index, liversomatic index, condition factor, hematocrit, lactate in blood and chloride ions in the blood plasma are generally stable from station to station and from year to year. The percentage of different leucocytes showed a comparatively large variation from one year to the next. Ethoxyresorufin- O-deethylase has shown an increase in activity over recent years indicating an increased exposure to pollutants.

Blood Plasma Levels of Sex Steroid Hormones and Vitellogenin in Striped Bass ( Morone saxatilis ) Exposed to 3,3',4,4'-Tetrachlorobiphenyl (TCB)

Exposure to polychlorinated biphenyls (PCB) can impair reproductive processes in fish. Laboratory studies have demonstrated adverse effects in several different fish species. Evidence also exits for an association between exposure to PCBs and related compounds and impaired reproduction in wild fish. Although the mechanism of reproductive toxicity of PCBs is unclear, it appears that PCBs act of several different levels of the hypothalamus-pituitary-gonadal axis (HPG). Because of their structural similarity to 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin), planar PCB congengers (e.g. 3,3`,4,4`-tetrachlorobiphenyl (TCB)) are among the most toxic PCBs. Both TCB and dioxon are reproductive toxicants in fish. TCB exposure (via intraperitoneal injections) impaired maturation in adult female white perch (Monroe americana) and reduced egg deposition in killifish (Fundulus heteroclitus). Larval or fry survival was also reduced following either maternal exposure to TCB for white perch or injections of TCB into fertilized eggs of rainbow trout. This study investigate the effects of exposure to TCB on reproductive processes in female striped bass. 12 refs., 2 tabs.

Growth and Feeding Responses of Male versus Female Yellow Perch (Perca flavescens) Treated with Estradiol-17β

In yellow perch (Perca flavescens) (initially 13–16 g total weight) fed to satiation (3.0–3.5% of body weight per day), estradiol-17β (E2) at 15 μg/g diet stimulated weight gain and food consumption of both sexes but did not influence food conversion efficiency (FCE), as measured by weight gain of fish per weight of food consumed. Females fed to satiation gained more weight, consumed more food, and had higher FCE than males. In perch fed a restricted ration (1.2% of body weight per day), the differences between the sexes in weight gain were reduced and due entirely to differences in FCE, and weight gain was not improved by E2. Spatial segregation or integration of the sexes had no influence on sex-related growth patterns in perch fed either the satiation or restricted ration. Carcass composition of perch treated for 84 d with E2 at 2, 20, or 50 μg/g diet did not differ from that of controls. These data indicate that (1) estrogens promote growth in yellow perch by stimulating food consumption, (2) female perch outgrow males because of both greater food consumption and higher FCE, and (3) growth differences between the sexes are not a consequence of intersexual competition for food.

Plasma thyroxine levels in freshwater perch: Influence of season, gonadotropins, and gonadal hormones

Plasma thyroxine (T 4) of a freshwater female perch Anabas testudineus (Bloch) has been measured by specific radioimmunoassay (RIA). Monitoring of plasma T 4 throughout the year showed that July to early September (spawning stage) had the highest T 4 and late September to January (postspawning stage) had the lowest T 4. The plasma T 4 cycle was coincident with the ovarian cycle. Treatment of intact perch with salmon gonadotropin (SG-G100) or ovine LH (500 ng/100 g body wt) markedly enhanced plasma T 4 levels. Ovine FSH was without any effect. Ovarian steroids, estrone and 17β-estradiol (100 ng/100 g body wt), also significantly augmented T 4 level whereas estriol or progesterone had no such effect. There was a striking fall of plasma T 4 in ovariectomized fish. The drop of T 4 due to ovariectomy could not be reversed by SG-G100 but administration of estrone or 17β-estradiol to ovariectomized fish effectively reversed the drop of plasma T 4 level. These findings suggest that gonadotropin's stimulatory effect on perch thyroid is mediated via the release of ovarian steroids.

Metacercarial distribution of Apophallus brevis (Heterophyidae) in yellow perch (Perca flavescens) from the Heming Lake study area

During a fish parasite survey in 1980 and 1981, 395 yellow perch (Perca flavescens) were removed from the Heming Lake study area (54°53′ N, 101°07′ W). Encysted Apophallus brevis metacercariae were found in the body musculature of perch from six lakes as well as the eye and body musculature of perch in Heming Lake. Species identity was confirmed with experimental infections in ring-billed (Larus delawarensis) and herring (Larus argentatus) gulls. No significant differences were found in prevalences or mean intensities of A. brevis metacercariae between male and female perch in Heming Lake. Prevalence levels remained high in most age-classes of Heming Lake perch and mean intensity differences were not significant for all ages beyond 1 year old. Slight variations from these Heming Lake results were found in other lakes. Prevalence levels of A. brevis in Heming Lake perch remained more or less constant during the open water seasons. Mean intensities dropped significantly from June to July and increased in August and October. Monthly fluctuations are probably the result of recruitment of the parasite and a loss of heavily infected hosts. The variance to mean ratios of A. brevis in perch from Heming, Home, and Demarch lakes showed that these parasite populations were overdispersed, and the distribution of each was found to fit the negative binomial. The authors question the use of variance to mean ratios or other statistics dealing with overdispersion in predicting loss or recruitment for all parasite systems.

Multivariate Analysis as a Means of Comparing Growth in Fish

The Hotelling's T2 is described as a test for differences between like von Bertalanffy growth parameters estimated from two fish groups when these parameters are correlated. Equations to calculate T2 are presented as are equations to modify T2 to an F statistic for use in testing. Simultaneous confidence intervals and critical F values are described to separate effects of parameters on observed differences in growth. Assumptions made by the T2 technique are discussed, as are ways in which any bias caused by violating these assumptions is lessened. Two numerical examples concerning growth differences among groups of Pacific ocean perch (Sebastes alutus) are provided. Growth of male and of female perch captured off the Columbia River is different with L∞ being the most statistically significant parameter and t0 the least. Growth of male perch captured off Vancouver Island and off the Columbia River is also different with only L∞ statistically significant.Key words: Hotelling's T2, multivariate statistics, Pacific ocean perch, von Bertalanffy, growth

Observations on the biology of the perch, Perca fluviatilis, in the River Stour, Dorset

SUMMARY. Opercular bones from 323 perch from the River Stour were used for age and back‐calculated growth determinations. Annuli were formed during May at the beginning of the growth period. Growth was minimal from October to April. Female perch grew faster than males, and the growth rates of both sexes were higher than those observed in most other European waters. Spawning occurred during late April and early May; male gonads began development in August and had attained their maximum weight in September, but the ovaries developed gradually from August until April. Immature perch had an annual cycle of condition with a maximum in June‐July and a minimum in December‐January. The condition of mature males and females was affected by the gonad cycle. The fecundity of Stour perch is expressed by the formula: log egg number = 2.40 log length (mm) ‐ 1.34.Approximately 25% of males were mature at age I and all were mature at age II, whereas most females did not spawn until age III. Ephemeroptera nymphs and minnow fry constituted the bulk of the diet of 0‐group perch; Ephemeroptera nymphs, minnow fry and Corixidae were the most numerous items in I group perch, whereas older perch contained Corixidae and a wider range of fish prey species, although minnows were the most numerous of these.

Reproductive behavior in the female shiner perch Cymatogaster aggregata

Female shiner perch, Cymatogaster aggregata Gibbons, initiate and display reproductive behaviors that are similar to behaviors shown by males during their reproductive cycle. No consistent quantitative differences in behavior are found when females in three reproductive states are compared.

Seasonal Changes of Fat Content in the Yellow Perch (Perca flavescens) of Two Laurentian Lakes

Different body fat reserves in male and female yellow perch (Perca flavescens) may determine a marked differential mortality during the winter. This was revealed by a study in two Laurentian lakes of the Province of Quebec harboring stunted yellow perch with a marked predominance of males. The proportion of females in each year-class is markedly smaller, thus suggesting a higher mortality among immature and mature females than among males.In an attempt to explain the differential mortality, the seasonal variation of body fat content in males and females was measured; also the fat level at time of death caused by starvation under laboratory conditions was determined. The results showed that in the females the body fat content falls to a critical level of about 2% at least 4 mo before spawning, whereas the males maintain a fat level of almost 5% throughout winter.

Croissance en longueur et en poids des perchaudes Perca flavescens de la Grande Anse de l'île Perrot au lac Saint-Louis

In this study, growth in length is based upon age determination on the opercular bones of 2170 specimens, collected throughout the year from June 1967 to October 1969. The opercular bone shows allometric growth and this is taken into account in back calculations. Grande Anse perch show comparatively rapid growth. Growth of males is slower than that of females. Seasonal growth extends from May to September. Faster growing fish reach sexual maturity earlier in life. Length–weight relationship exponent is 3.107. Due to the weight of the gonads, female perch show maximum condition index values in winter.

Some Effects of Shape and Structure of Fish on Selectivity of Gillnets

Selectivity curves for three species of fish taken in South Bay, Manitoulin Island, and in Georgian Bay during 1954–59 with gangs of nylon gillnets differed with respect to mode, skew, and kurtosis. A graphic method was developed to describe one aspect of body shape, namely the relation between girth and distance from the snout, which would affect selectivity. Surprisingly, the shapes of mature (but not gravid) and immature perch and suckers of both sexes could be described by the same curve. Hence, differences in body shape did not account for differences in the selectivity of these species. In contrast, the taper for gravid female perch was markedly different from that for nongravid, as might be expected. Catches in which the positions where caught were carefully identified showed that most of the fish were caught either on the opercle or near the position of maximum girth. That the fish could be caught at different positions accounted for most of the skew in the selectivity curves based on maximum girth. Selectivity curves plotted on the basis of girth where caught, rather than on maximum girth or length, show that efficiency of capture was maximal when the girth of the fish was 1.0–1.2 times as great as the perimeter of the mesh. Efficiency was negligible at girth/perimeter ratios smaller than 0.8 or 0.9 and it declined rapidly at ratios greater than 1.2. However, a few fish were taken at ratios up to 1.5 or 1.6.

Relationships of Female Age and Size to Embryo Number and Size in the Shiner Perch, Cymatogaster aggregata

Ages, lengths, and weights were determined for 124 female shiner perch, Cymatogaster aggregata Gibbons, collected in Yaquina Bay, Oregon, from May 17 through June 29, 1968. Embryos (1005) were obtained from 111 gravid females either by dissection (737) or at parturition in the laboratory (268). Embryo lengths, weights, and numbers per female parent were determined.As females increased in age from 1 to 6 years, their mean fork length increased from 9.32 to 13.65 cm, their weight from 13.65 to 47.78 g, and the mean number of embryos per parent female increased from 5.83 to 20.00. The equations and their correlation coefficients (R) computed for the relationships of embryo number (Y) to parent female fork length, weight, and age are, respectively: log Y = −1.892 + 2.735 log X (R = 0.89); Y = 1.131 + 0.313 X (R = 0.70); and Y = 4.23 + 1.73 X (R = 0.51). Embryo size at birth was also directly related to female parent size. The equations computed for the relationships of total length of embryo at birth (Y) to parent female fork length and parent female weight are, respectively: Y = 24.211 + 1.620 X (R = 0.79); and Y = 0.384 + 0.015 X (R = 0.72). The equation computed for the relationship of embryo weight (Y) to embryo length at birth is Y = −2.266 + 0.712 X (R = 0.95).

Dependence of Total Annual Growth in Yellow Perch on Temperature

Total yearly growth of female yellow perch, Perca flavescens (Mitchill), in South Bay, Lake Huron, estimated by the distance along the lateral radius from last annulus to scale edge, showed a marked relationship to mean water temperature at a depth of 20 ft. When published data on growth of perch in Lower Red Lake, Minnesota, were compared with mean air temperatures for the period June through September at Redlake, no such relationship could be demonstrated. The reasons for the different results obtained in these and in other studies could not be determined.

Growth Rate Studies of Saugers, Stizostedion Canadense Canadense (Smith) and Yellow Perch, Perca Flavescens (Mitchill) from Lake of the Woods, Minnesota

Abstract The scale method of growth analysis is applicable to the Lake of the Woods saugers and the body-scale relationship was described by a third degree poly-nominal. Saugers up to Age Class X were studied and the most rapid growth in length occurred during the first year of life. Lee's phenomenon was pronounced and was apparently due to the selective removal of the faster growing fish. Weight increased approximately as the 3,058 power of the standard length and the average “K” was 1.27. Females were more abundant than males. The number of eggs per female varied from 43,400–48,500. There appeared to be a correlation between the abundance of saugers in various year classes and the June rainfall and cooler summer temperatures during the year of hatching. The yellow perch body-scale relationship was also curvilinear and was corrected for in the calculation of growth. Female perch grew more rapidly than the males and were longer-lived. Lee's phenomenon appeared to be due largely to selective sampling. No g...