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PubMed2003

Modulation of perch connexin35 hemi-channels by cyclic AMP requires a protein kinase A phosphorylation site.

Retinal neurons are coupled via gap junctions, which function as electrical synapses that are gated by ambient light conditions. Gap junctions connecting either horizontal cells or AII amacrine cells are inhibited by the neurotransmitter dopamine, via the activation of the cyclic adenosine monophosphate (cAMP)/protein kinase A (PKA) signaling pathway. Fish connexin35 (Cx35) and its mouse ortholog, Cx36, are good candidates to undergo dopaminergic modulation, because they have been detected in the inner plexiform layer of the retina, where Type II amacrine cells establish synaptic contacts. We have taken advantage of the ability of certain connexins to form functional connexons (hemi-channels), when expressed in Xenopus oocytes, to investigate whether pharmacological elevation of cAMP modulates voltage-activated hemi-channel currents in single oocytes. Injection of perch Cx35 RNA into Xenopus oocytes induced outward voltage-dependent currents that were recorded at positive membrane potentials. Incubation of oocytes with 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP), a membrane permeable cAMP analog, resulted in a dose-dependent and reversible inhibition of hemi-channel currents at the more positive voltage steps. In contrast, treatment with 8-Br-cAMP did not have any effect on hemi-channel currents induced by skate Cx35. Amino acid sequence comparison of the two fish connexins revealed, in the middle cytoplasmic loop of perch Cx35, the presence of a PKA consensus sequence that was absent in the skate connexin. The results obtained with two constructs in which the putative PKA phosphorylation site was either suppressed (perch Cx35R108Q) or introduced (skate Cx35Q108R) indicate that it is responsible for the inhibition of hemi-channel currents. These studies demonstrate that perch Cx35 is a target of the cAMP/PKA signaling pathway and identify a consensus PKA phosphorylation site that is required for channel gating.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed2002

Lipid metabolism and FA composition in tissues of Eurasian perch Perca fluviatilis as influenced by dietary fats.

Eurasian perch, Perca fluviatilis, were fed a semipurified fat-free diet for 4 wk, followed by a 16% feeding supplementation of either olive oil (OO), safflower oil (SO), linseed oil (LO), or cod liver oil (CLO) as the only lipid source in each diet for 10 wk. Significant reductions in total lipid of tissues were observed (31.4% in viscera, 66.7% in muscle, and 74.1% in liver) after feeding the fat-free diet. The SO-, LO-, and CLO-fed fish significantly increased lipid deposition in liver and viscera compared to fish fed the OO diet; however, muscle lipid levels were not significantly affected. Large amounts of dietary 18:1 n-9 were incorporated directly into tissue lipids when fish were fed the OO diet. The LO diet significantly elevated 18:4n-3, 20:5n-3, 22:5n-3, and 22:6n-3 in the liver compared to fish fed OO or SO diets, and the n-3/n-6 ratio was 16 times that of the SO group, with significantly high desaturation and elongation products of 18:3n-3. These results suggest that delta6 and delta5 desaturases are highly active in Eurasian perch, and that the enzymes at this dietary n-3/n-6 ratio favor 18:3n-3 over 18:2n-6 as substrate. The SO diet significantly increased 18:3n-6, 20:3n-6, and 22:5n-6 in the liver and significantly decreased EPA and DHA. This indicates that desaturation enzymes were not specifically favoring n-3 over n-6 acids in perch lipid metabolism, and that these elongation and desaturation enzymes were influenced by n-3 and n-6 FA content in the diet. The present study indicates that high tissue content of DHA in the muscle of Eurasian perch was attributable to the greater ability for n-3 acid bioconversion.

Animal Feed↗
PubMed1986

Binding of thyroid hormone to isolated ovarian nuclei from a freshwater perch, Anabas testudineus.

High affinity, low capacity 3,5,3'-triiodo-L-thyronine (T3) specific binding was detected in the pure nuclei preparation from ovarian tissue of freshwater perch by employing an in vitro thyroid hormone binding assay. Under standardized assay conditions of pH 7.0 at 30 degrees and 1 hr incubation time, the binding in the ovarian nuclei was saturable with a Kd 9.1 X 10(-9) M. For comparison, a Scatchard analysis of T3 binding to perch hepatic nuclei was done and a higher Kd value (16.89 X 10(-9) M) with twofold increase in maximum binding capacity (MBC 8.882 and 4.312 pmol/mg DNA in liver and ovary, respectively) was observed. Competitive inhibition studies showed ovarian T3 binding to be hormone specific with relative binding affinities comparable to T3 binding in other systems. T3 binding to the nuclear preparation from tail kidney and brain tissue of perch was considerably lower in comparison to liver and ovarian nuclei. Functional relevance of T3 binding to perch ovarian nuclei was tested by incubating ovarian tissue in vitro with T3. T3 significantly (P less than 0.001) increased protein synthesis in comparison to control.

Animals↗
PubMed1989

In vitro ovulation, prostaglandin synthesis, and proteolysis in isolated ovarian components of yellow perch (Perca flavescens): effects of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one and phorbol ester.

The present study investigated the effects of 17 alpha,20 beta-dihydroxy-4-pregnen-3-one (17,20 B-P) on (1) ovulation of isolated perch follicles in which the extrafollicular (EF) ovarian tissue had been removed; (2) prostaglandin F (PGF) and prostaglandin E (PGE) synthesis in EF tissue and intact (= follicles attached to EF tissue) and isolated follicles by radioimmunoassay and [14C]arachidonic acid incorporation; and (3) proteolysis in EF tissue and intact and isolated follicles by substrate sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In addition, the ovulatory and proteolytic effects of the phorbol ester, phorbol-12-myristate-13-acetate (PMA), and the calcium ionophore A23187 on 17,20B-P-stimulated follicles were also studied in the presence/absence of indomethacin (IM) and nordihydroguaiaretic acid (NDGA). Ultrastructural analyses revealed that the preparation of isolated follicles also removed the surface epithelium of the follicle. While 17,20B-P stimulated ovulation and an increase in PGF and PGE in incubates of intact perch follicles, it did not in incubates of isolated follicles. In contrast, PMA, A23187, and a combination of PMA and A23187 stimulated ovulation of these isolated follicles. PMA/A23187-induced ovulation could be blocked by NDGA but not IM, and two hydroxyeicosatetraenoic acids (11- and 15-HETEs) were capable of partially reversing the NDGA block. Incorporations with [14C]arachidonic acid revealed that the EF tissue had a significant potential to produce PGF; however, 17,20B-P did not stimulate an increase in PGF or PGE (measured by RIA) in incubates of EF tissue alone. In addition, neither ovulation nor an increase in prostaglandins was observed in cocultures of isolated follicles and EF tissue. One major protease (66 kDa) was observed in the medium during incubation of intact and isolated perch follicles. No protease activity was present in incubates of EF tissue alone. Protease activity in 17,20B-P-stimulated incubates of intact tissue was significantly higher than in steroid-stimulated incubates of isolated follicles. Protease activity increased in the medium during incubation with PMA or a combination of PMA and A23187. This activity was blocked by NDGA but not IM. The NDGA block was partially reversed by 11-HETE. The combined results suggest that there is an interaction of EF tissue and follicle that is necessary, particularly for the stimulation of ovulation and prostaglandin production. Further, the results with phorbol esters and NDGA suggest that the follicular control of ovulation in perch may involve protein kinase C acting through the production of a lipoxygenase product.

17-Hydroxycorticosteroids↗
PubMed1987

Few intra-lake variations of physiological parameters in perch, Perca fluviatilis.

Intra-lake variations in physiological parameters, representing haematology, plasma ion composition and carbohydrate metabolism, were investigated in perch (Perca fluviatilis), inhabiting a comparatively unpolluted lake. Provided the perch were subjected to a standardized procedure for capture, handling, recovery after capture, and sampling, only few and minor differences were observed in 21 parameters investigated when 3 groups were compared to a control group of perch. It is concluded that the experimental design used is suitable for the examination of the physiological status of perch in the field.

Animals↗
PubMed2005

Dynamics of Cd, Cu and Zn accumulation in organs and sub-cellular fractions in field transplanted juvenile yellow perch (Perca flavescens).

Juvenile yellow perch (Perca flavescens) were caught in a reference lake and transplanted to cages held within a lake impacted by mining activities, with elevated levels of aqueous bioavailable copper (Cu(2+)), zinc (Zn(2+)) and cadmium (Cd(2+)). Fish were sampled from the cages over 70 d and changes in metal concentrations were followed over time in the gills, gut, liver and kidney. In addition, the hepatic sub-cellular partitioning of the three metals was determined by differential centrifugation of liver samples, yielding the following fractions: cellular debris; organelles; heat-denaturable proteins (HDP); and heat-stable proteins (HSP) (including metallothionein). In transplanted fish, Cd concentrations increased in all the organs sampled, whereas Cu mainly increased in the gills, gut and liver but not the kidney; some slight accumulation of Zn occurred in the kidneys and gills of the transplanted fish. The sub-cellular partitioning results demonstrated that metal-handling strategies in juvenile yellow perch differed among metals. Cellular sequestration in the HSP fraction was an important strategy used by these fish in response to increased ambient Cd. Accumulation of Zn was not seen in the organs examined, indicating that transplanted perch were able to either reduce influx, or increase efflux rates of this metal. The response of yellow perch to elevated ambient Cu appeared to combine the strategies used for Cd and Zn, as both cellular sequestration and reduced accumulation were observed in transplanted fish.

Animals↗
PubMed2006

Steroid biosynthetic enzyme activities in leachate-exposed female perch (Perca fluviatilis) as biomarkers for endocrine disruption.

Studies have shown that adult female perch in a freshwater lake, Molnbyggen, Sweden, have a reproductive disorder caused by unidentified endocrine disrupting compounds (EDCs) leaching from a local refuse dump. The adverse effects include shallow open sores, low ratio of sexually mature individuals, low gonadosomatic index and low circulating levels of androgens. We hypothesised that the low androgen levels could be a result of impaired production and/or stimulated excretion of androgens by EDCs. From October 2000 to November 2001, at time-points important in the perch reproductive cycle, adult female perch were collected in Molnbyggen and in the reference lake, Djursjön. The activities of three key enzymes in androgen biosynthesis: 17alpha-hydroxylase (17OHlase), 17,20-lyase (lyase) and 17beta-hydroxysteroid dehydrogenase (17betaHSD) were determined in head kidney or ovary. The relationship between enzyme activities and plasma steroid concentrations was examined. Ovarian histopathology and the determination of brain aromatase activity were also included in the study. Similar 17OHlase, 17betaHSD and aromatase activities were found in Molnbyggen females and reference fish throughout the year. Head kidney 17OHlase showed a positive correlation to cortisol levels (r=0.754; p<0.001) but not to androgen levels. Molnbyggen females exhibited lower ovarian lyase activity during vitellogenesis than reference fish. Atretic oocytes were on most occasions more frequent in sexually immature than in sexually mature females. The results suggest that neither 17OHlase, 17betaHSD nor aromatase is the target for EDCs disrupting the androgen homeostasis of exposed female perch. Further investigation is needed to establish the role of decreased ovarian lyase activity in endocrine homeostasis, but the possibility of increased excretion of androgens should also be examined.

17-Hydroxysteroid Dehydrogenases↗
PubMed2003

Vitellogenin in carp (Cyprinus carpio) and perch (Perca fluviatilis): purification, characterization and development of an ELISA for the detection of estrogenic effects.

Vitellogenin (VTG), a phospholipoglycoprotein precursor of egg yolk is synthesized and secreted in the liver in response to circulating estrogens in female fish. Thus, the presence of VTG in male fish is a useful biomarker to identify estrogenic activity of natural or anthropogenic substances in sewage effluents. We report the purification of carp (Cyprinus carpio) and perch (Perca fluviatilis) VTG with the subsequent development and characterization of a specific ELISA for VTG measurement. VTG was purified by combination of ion exchange chromatography and size exclusion chromatography. The purified proteins were used as antigen for antibody production, as standard and tracer in the assay. Carp VTG was stable and showed a characteristic double band after Western blotting of the purified protein and in serum samples, respectively. In perch samples, several bands with lower molecular weight were present and appeared to be degradation products of VTG. The development of the carp VTG ELISA led to a sensitive and valid test system with inter-assay coefficients of variation between 3.0 and 12.3%. In contrast to carp, the described ELISA for perch VTG showed a much higher inter-assay variation up to 24%, possibly attributable to fast protein degradation. In conclusion, the described two-step chromatography is a simple purification method for VTG. Immunological and electrophoretical test systems are valid methods to determine VTG in some species like carp, but for other species like perch in which VTG is not stable, these methods are not applicable.

Animals↗
PubMed1998

Concentrations and spatial variations of cyclodienes and other organochlorines in herring and perch from the Baltic Sea.

Herring (Clupea harengus) and perch (Perca fluviatilis) were collected in the northern and southern Baltic Sea and analyzed for the presence of the cyclodiene pesticides chlordane (CHL), heptachlor, aldrin, dieldrin, endrin, isodrin, endosulfan and mirex, as well as other organochlorine contaminants, hexachlorocyclohexanes (HCHs), DDTs, hexachlorobenzene (HCBz) and polychlorinated biphenyls (PCBs) in order to investigate concentrations, accumulation and differences in geographical distribution. In the northern part of the Baltic Sea, Gulf of Bothnia, herring were collected at two pelagic stations, one in the Bothnian Bay (BB) and the other in the Bothnian Sea (BS), respectively; perch were collected at four coastal locations along the Swedish coast. All these locations were selected to represent background areas except one in the vicinity of an industrialised and contaminated area. Both specimens were also caught in the southern part of the Baltic Sea, in the Gulf of Gdansk (GG), Poland, a potentially highly polluted area. From the eight cyclodiene pesticides analyzed, three were detected in herring and perch samples, including 12 different CHL-related compounds, dieldrin and mirex. To our knowledge, it is the first time that mirex has been detected in samples from the Baltic Sea. Neither heptachlor, aldrin, endrin, isodrin nor endosulfan were found. However, HCHs, DDTs, HCBz and PCBs were found in every sample investigated, and the concentrations ranged e.g. for the cyclodiene chemicals dieldrin and CHL-related compounds from 30 to 170 ng/g lipid and for PCBs from 360 to 5400 ng/g lipid, both fish species included. Differences in contamination burden between the sites can be seen, e.g. for herring the BB and GG locals were similar, and generally lower than BS for all chemicals except that of DDT where GG was the highest. For the perch samples the industrialised location had markedly higher concentrations of HCBz and PCBs than the other locations. This species also identifies GG as the most DDT contaminated site among the three studied areas.

Animals↗
PubMed2002

Seasonal variations in condition and liver metal concentrations of yellow perch (Perca flavescens) from a metal-contaminated environment.

The relationships between liver metal (Cu, Zn and Ni) concentration and physical condition of yellow perch (Perca flavescens) were compared in fish sampled in five northeastern Ontario Lakes in the spring and seven lakes in the fall of 1997. These lakes represented a wide range of metal contamination, pH, dissolved organic carbon (DOC) and alkalinity. Lakes situated closest to emission point source had lower pH, alkalinity and DOC and higher aqueous metal concentrations than other lakes in this study. Fish from these lakes displayed higher liver metal concentrations. Seasonal variations in liver metal concentrations were observed in the most metal-contaminated lakes, with higher Cu levels in the spring and higher Zn and Ni concentrations in the fall. These fish had lower indicators of physical condition than fish from cleaner lakes. In particular, more metal-contaminated fish were smaller for a similar age, indicating slower growth rate, and had lower relative condition factor and scaling coefficients. The scaling coefficient is a descriptor of the growth pattern of fish, and higher values indicate increased weight gain per unit of growth in length. Negative (P<0.05) relationships are reported between lake alkalinity and liver Cu concentration (in both seasons) and Zn concentration (in spring only). In both seasons mean liver Cu content was negatively associated (P<0.05) with the scaling coefficient of the fish samples. With these data, we propose the use of the scaling coefficient as a simple biomonitoring tool to detect metal effects on the physical condition of yellow perch. Data presented here provide information on seasonal variations in liver metal concentration and condition of yellow perch that should be considered in the design of field studies investigating physiological effects of metals in wild fish. This work also describes a gradient of lake and fish metal contamination that is related to the physical condition of yellow perch. This system provides a unique research opportunity to further our limited knowledge of the effects of metals on the physiology of wild fish.

Animals↗
PubMed2000

Hepatic glucose phosphorylating activities in perch (Perca fluviatilis) after different dietary treatments.

Increased activity of hepatic glucose phosphorylation was observed in perch after feeding previously fasted fish. When a pellet diet containing 14% carbohydrate was given, most of the increased activity had a low affinity towards glucose (S0.5 = 19.5 mM) and resembled the mammalian glucokinase (Hexokinase IV or D) and the glucokinase-like activity previously observed in salmon liver. In addition, increased activity of a hexokinase with high affinity towards glucose (Km = 0.50 mM) was observed with the pellet diet. An increase in the activity of this hexokinase alone was observed when the fish were fed with filet of cod containing less than 0.2% carbohydrate. Perch with a very high hepatic glucokinase-like activity after eating the pellet diet had high activities of pyruvate kinase and glucose-6-phosphate dehydrogenase, indicating a high capacity of glycolysis and carbohydrate utilization. Simultaneously, the activity of glycogen phosphorylase was strongly reduced while the activity of fructose-1,6-bisphosphatase was not significantly changed. These observations were made with perch captured in the spawning season and brought to the laboratory. Assays of glucose phosphorylation in livers of perch eating the natural diet (insects) in the lake showed no glucokinase-like activity.

Animals↗
PubMed2001

Interspecific interactions between larval digeneans in the eyes of perch, Perca fluviatilis.

The changes in prevalence and abundance of the three species of metacercariae in the humour of the eyes of perch Perca fluviatilis in Slapton Ley, Devon, have been monitored over a period of 29 years. Earlier studies had revealed that Diplostomum gasterostei was originally the sole occupant of this niche, but Tylodelphys clavata colonised in 1973 and T. podicipina in 1976. A decline in the number of perch with heavy infections of D. gasterostei was significantly negatively correlated with population abundance of T. clavata and a decline in recruitment rate of D. gasterostei coincided with the population increase in T. podicipino over the period 1976-1979. It was suggested that the decline in population size of D. gasterostei was due to inter-specific competition, but this hypothesis could not be tested experimentally. Subsequent investigations, reported here, confirmed the decline when the data set was extended to 1985. A severe decline in the perch population over the winter of 1984/1985 resulted in the disappearance of D. gasterostei and T. podicipina and this was followed by a slow recovery from 1990 onwards. This natural experiment provided an opportunity to test the hypothesis. Only T. clavata survived throughout the perch crash and the population continued at pre-crash levels up to 1999. Its congener T. podicipina did not re-appear until 1994 and was probably a re-introduction: it did not attain pre-crash levels until 1999. It is likely that D. gasterostei survived the crash as it re-appeared in 1991, but was confined to young of the year fish and barely approached pre-crash levels even in 1999. Its continual low levels cannot be explained by changes in the lake or in densities of snail intermediate or bird definitive hosts. New data revealed that the suspensory ligaments of the eye were the preferred site of all three species and that the eye was partitioned out between them. The data from the post-crash period do not refute but rather confirm earlier conclusions that inter-specific competition is responsible for the decline in D. gasterostei and this remains the preferred hypothesis.

Animals↗
PubMed2004

PCR-ELISA for the semiquantitative detection of Nile perch (Lates niloticus) in sterilized fish muscle mixtures.

A PCR-ELISA technique was developed for the semiquantitative detection of Nile perch (Lates niloticus) in experimentally sterilized fish muscle mixtures. Specific oligonucleotides derived from the 5S rDNA gene of Nile perch were selected. A forward primer, together with a reverse digoxigenin-labeled primer, permitted the amplification of specific 185 bp DNA fragments showing DNA intensities proportional to the contents of Nile perch muscle tissue in the fish mixtures. A biotinylated probe immobilized onto streptavidin-coated microplates was used to capture the digoxigenin-labeled fragments that were detected with peroxidase antidigoxigenin conjugate. Subsequent enzymatic conversion of substrate gave distinct absorbance differences when assaying fish binary mixtures containing different percentages of Nile perch muscle.

Animals↗
PubMed2001

Kin-structured subpopulations in Eurasian perch (Perca fluviatilis L.).

Based on ecological and behavioural studies it has been assumed that Eurasian perch (Perca fluviatilis) within one lake may not represent one panmictic population, but that they are subdivided into subpopulations. In order to investigate the genetic substructuring of populations, we used gene frequencies of five microsatellite loci to compare perch from six different sites from Lake Constance, Germany, and as outgroups perch from the lake Grosser Vätersee, Berlin, and two Swiss lakes, Lake Zurich and Lake Walensee. We examined whether homing behaviour of subadults to the spawning sites of their parents occurs and whether philopatric behaviour of adults results in significant population genetic substructuring. The distribution of genetic variation revealed two major, genetically distinct populations in Lake Constance: one in the eastern part of the lake and another in the western part (GST = 0.07). Within each of these two populations, no further genetic substructuring, nor any indication of inbreeding could be detected, either because genetic exchange was sufficiently high or because the time since separation has been too short. Homing behaviour of subadults to parental spawning sites after having spent several weeks of their life cycle in the pelagic zone could not be detected. Instead, subadults stay within either the western or the eastern region of the lake. There is evidence that some shoals contain full- and half-sibs. Despite females spawning in close proximity to each other, some siblings stay together. This might suggest that perch possess kin preferences and kin recognition.

Animals↗
PubMed2005

Aeromonas sobria, a causative agent of disease in farmed perch, Perca fluviatilis L.

Significant numbers of perch, Perca fluviatilis, raised on a pilot fish farm in Switzerland presented focal skin lesions on the lateral sides and fin rot. Mortality rates reached levels of up to 1% of the total fish on the farm per day. Virtually pure cultures of Aeromonas sobria were isolated from the liver, kidney, spleen and skin lesions of affected fish. Aeromonas sobria isolated from the farmed perch had a haemolytic effect on sheep and trout erythrocytes, autoaggregated, was cytotoxic for cultured fish cells and possessed genes involved in type III protein secretion. Experimental infection of naive perch with a single colony isolate of A. sobria from an affected farm fish resulted in the development of clinical signs identical to those seen on the farm. The results indicate that A. sobria can act as a primary pathogen of perch.

Aeromonas↗
PubMed1995

Influence of environmental temperature on experimental infection of redfin perch (Perca fluviatilis) and rainbow trout (Oncorhynchus mykiss) with epizootic haematopoietic necrosis virus, an Australian iridovirus.

Experimental transmission of epizootic haematopoietic necrosis virus (EHNV) to adult redfin perch Perca fluviatilis and juvenile rainbow trout Oncorhynchus mykiss was undertaken at different water temperatures using intraperitoneal (IP) and bath inoculation. Redfin perch were highly susceptible to EHNV by both routes of infection. Bath inoculation with as few as 0.08 TCID50.mL-1 was lethal. The incubation period in redfin perch was about 11 days at a water temperature of 19-21 degrees C but was longer at colder temperatures and disease did not occur at temperatures below 12 degrees C. The longest incubation period recorded in redfin perch was 28 days. Rainbow trout were not susceptible to infection by bath inoculation but the disease was reproduced after IP inoculation with 10(5.6) TCID50 at water temperatures ranging from 8-21 degrees C. The incubation period was 3-10 days at 19-21 degrees C, but was up to 32 days at 8-10 degrees C. Persistent infection with EHNV was detected by virus isolation in a clinically unaffected rainbow trout after 63 days. The implications of these findings in the understanding of the epidemiology of EHNV infection are discussed.

Animals↗
PubMed2002

Prevalence and intensity of Haemobaphes diceraus (Copepoda: Pennellidae) from shiner perch, Cymatogaster aggregata (Embiotocidae).

The prevalence and intensity of the hematophagous pennellid copepod Haemobaphes diceraus were monitored over a 10-mo period in shiner perch Cymatogaster aggregata at Pipers Lagoon, Nanaimo, British Columbia. The prevalence and mean intensity of metamorphosed adult female H. diceraus (n = 421) were 10.0% and 1.2 (+/-0.5 SD), respectively. The majority (97.9%) of infected fish had single infections, reflecting the possibility of intensity-dependent parasite-induced mortality, rejection of additional parasites, or both. Transforming females were detected throughout the year; however, there was no detectable seasonal pattern of colonization. Neither copepodids nor adult males of H. diceraus were observed on the gills of shiner perch, and this was consistent with the hypothesis that an intermediate host harbors these stages. Males of Haemobaphes sp. infected the gills of bay pipefish Syngnathus griseolineatus with a prevalence and mean intensity of 56.0% and 6.8 +/- 3.7, respectively. Transmission of H. diceraus to shiner perch probably occurs in inshore protected areas, where shiner perch ecologically overlap with the probable intermediate host of H. diceraus, the bay pipefish.

Animals↗
PubMedDate not supplied

[Parasite fauna of the perch fishes Percidae in waterbodies of the Kola Region].

Results of the parasitological investigation of two species of perch fisches (perch Perca fluviatilis and ruff Gymnocephalus cernuus) from Kola Region are given. 63 species of parasites were found on perch in 16 waterbodies belonging to the White Sea and Barents Sea basins (Myxosporea--3, Pleurostomata--1, Suctoria--2, Peritricha--21, Protozoa incertae sedis--1, Monogenea--2, Cestoda--6, Trematoda--10, Nemadota--8, Acanthocephala--4, Hirudinea--1, Bivalvia--1, Crustacea--3). 33 species of parasites were found on ruff in 5 waterbodies belonging to the White Sea basin (Cyrtostomata--1, Hymenostomata--1, Peritricha--8, Monogenea--2, Cestoda--6, Trematoda--9, Nematoda--2, Acanthospehala--2, Bivalvia--1, Crustacea--1). Data on the infestation of perch and ruff by different parasite species are obtained, occurrence of the parasites in the examined waterbodies is shown.

Animals↗