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1.
Salmon Salmo salar L. and brown trout S. trutta L. juveniles were examined for the presence of accidental monogenean ectoparasitic species of Gyrodactylus Nordmann, 1832 in the Baltic and White Sea basins of Russian Karelia in order to estimate the frequency of host-switching attempts on an ecological timescale. To collect phylogeographical information and for exact species identification, the parasites were characterised by nuclear internal transcribed spacer sequences of rDNA (ITS) and, for some species, also by their mitochondrial DNA (CO1 gene) sequences. Four accidental Gyrodactylus species were observed on salmon and brown trout. A few specimens of G. aphyae Malmberg, 1957, the normal host of which is the Eurasian minnow Phoxinus phoxinus (L.), were observed on lake salmon from the Rivers Kurzhma (Lake Kuito, White Sea basin) and Vidlitsa (Lake Ladoga, Baltic basin). G. lucii Kulakovskaya, 1952, a parasite of the northern pike Esox lucius L., was observed on salmon in the Kurzhma. In the River Vidlitsa, two specimens of G. papernai Ergens & Bychowsky, 1967, normally on stone loach Barbatula barbatula (L.), were found on salmon. On anadromous White Sea salmon in the River Pulonga in Chupa Bay, a few salmon parr carried small colonies of G. arcuatus Bychowsky, 1933, which were shown to have originated from the local three-spined stickleback Gasterosteus aculeatus L. consumed as prey. No specimens of Gyrodactylus salaris Malmberg, 1957 were observed, although the Pulonga is the nearest salmon spawning river to the River Keret', which is heavily infected with introduced G. salaris. In the River Satulinoja, Lake Ladoga, three specimens of G. lotae Gusev, 1953, from burbot Lota lota (L.), were collected from a single brown trout S. trutta. All nonspecific gyrodactylid infections on salmonids were judged to be temporary, because only a few specimens were observed on each of the small number of infected fishes. The prevalence of endemic G. salaris was also low, only 1% (Nfish = 296) in Lake Onega and 0.7% (Nfish = 255) in Lake Ladoga, while brown trout specific Gyrodactylus species were not observed on any of the 429 trout examined from the Ladoga basin. The host-specific and unspecific burden of Gyrodactylus spp. on these 'glacial relict' populations of salmon and brown trout was very low, suggesting a generalised resistance against the co-evolved freshwater parasite community, or some kind of 'vaccination' effect. These hypotheses deserve further testing. 相似文献
2.
Sexually matured rainbow trout, Oncorhynchus mykiss, were experimentally infected with the pathogenic Cryptobia salmositica. Spawning female trout were more susceptible to cryptobiosis than sexually mature males. Most infected females (seven of nine)
with eggs died before or shortly after spawning while all (nine) infected males survived the disease. Also, none of the uninfected
females died. Males initially increased milt production and sperm concentration; however semen production declined as the
disease progressed. Sperm from infected males fertilized more eggs than those from non-infected males. No differences in weight
and survival were observed between progeny of infected and uninfected males. 相似文献
3.
G. A. Sakuta E. V. Baidyuk A. A. Zhumagalieva B. N. Kudryavtsev 《Cell and Tissue Biology》2012,6(1):89-94
With the aid of cytofluorimetry and interference microscopy, the ploidy level and the hepatocyte ploidy class distribution
were studied and the dry mass of hepatocytes was measured in hepatocytes in liver of Chinese hamsters Cricetulus griseus and of Balb/c mice before and one month after partial hepatectomy. The mean ploidy level in hepatocytes of the Chinese hamster
normal liver amounted to 2.35 ± 0.03 c. The modal class was mononuclear hepatocytes with diploid nuclei (82.4 ± 1.3%). The
mean dry mass of hepatocytes amounted to 605.2 ± 4.8 pg. In the process of liver regeneration in the Chinese hamsters, the
ratio of ploidy classes and the hepatocyte dry mass did not change. After a similar liver resection in the mice, a significant
polyploidization of liver parenchyma occurred. The mean ploidy level in hepatocytes rose by 32%. Instead of 4cx2-hepatocytes,
the modal class became mononuclear octaploid cells the relative portion of which increased, on average, by five times. The
portion of binuclear hepatocytes with octaploid nuclei in mouse liver rose by more than five times. Thus, in the Chinese hamsters
Cricetulus griseus, unlike mice, regeneration of liver occurred exclusively at the expense of proliferation of hepatocytes. 相似文献
4.
A stereological study was performed on brown trout hepatocytes aiming to disclose whether there are basic gender differences when minimal levels of sex hormones exist, and also to establish a platform for both interspecific comparisons and physiological correlations. We used the so-called "design-based stereology" (with no shape, size or orientation assumptions) and also some new related statistics. Two-year-old brown trout were collected in April, and the livers were fixed by perfusion. From liver slicing to microscopical field selection, systematic sampling was used. Stereology was applied at light and electron microscopy. Target parameters were the relative and total hepatocyte number, the mean individual hepatocyte volume and surface, and also both relative and total volumes, and surfaces, either of organelles or of cell compartments. Observed variability was usually high, but the precision of estimates was proved to be globally adequate facing the true biological variation amongst specimens. Females had more hepatocytes per liver (1.79x10(9) vs. 1.12x10(9)). Considering the individual hepatocytes, whereas no gender differences were detected in the cell volume, males had higher values of nuclear volume (199 vs. 151 microm3) and surface (170 vs. 131 microm2), endoplasmic reticulum volume (1,300 vs. 824 microm3), and microvilli volume (82 vs. 54 microm3) and surface (1,445 vs. 975 microm2). However, when dealing with quantities per liver, gender differences were found only in the volumes of dense bodies (56 vs. 97 mm3) and of residual cytoplasm (169 vs. 341 mm3)--both volumes were higher in females. Functional implications of data are discussed, namely that females seem to have basic structural traits for coping with the later demands of breeding. Data also support that structural remodelling of hepatocytes occurs after breeding, urging to pursue seasonal studies (namely on lysosomes). We advanced the hypothesis that genders differ in microvilli surface just to maintain an optimal physiological surface-to-volume ratio. Interspecific similarities and differences were disclosed. For example, the number of hepatocytes/cm3 of parenchyma of brown trout was much lower than those reported in rainbow trout, but in both trouts females seem to have an higher cell number. In addition, when comparing the size of hepatocytes of brown trout with that from other fish and mammals it was suggested that major interspecific differences exist. 相似文献
5.
Studies of spawning water bodies in the city of Moscow have shown that the urban populations of common (Rana temporaria) and moor (R. arvalis) frogs are small compared with suburban populations, and their individuals lead a hidden mode of life. The recorded increase in the fecundity of females from several populations of the city of Moscow may be accompanied by an increase or the preservation of the diameter of eggs as compared with the same indicator for suburban populations. The populations in which the females produced many small eggs died out during the study period. The most prosperous populations are urban populations of brown frogs whose females spawned eggs of various sizes. We consider the formation of these clutches as a manifestation of the bet-hedging strategy compensating for mortality in adverse and unstable environmental conditions. 相似文献
6.
P. Simonović A. Tošić D. Škraba Jurlina V. Nikolić M. Piria T. Tomljanović N. Šprem D. Mrdak D. Milošević A. Bećiraj R. Dekić M. Povž 《Journal of Ichthyology》2017,57(4):603-616
The part of the River Danube basin in the Western Balkans region (11 sampled localities and 57 in total with using of published data) revealed the remarkable diversity of brown trout assessed using the Control Region (CR) of mitochondrial DNA (mtDNA) as a molecular marker. The greatest number of brown trout populations holds brown trout of the Da1 haplotype. Particular distinct haplotypes are limited to isolated brown trout stocks. There are haplotypes of Danubian (Da), and those of Atlantic (At), Adriatic (Ad) and marmoratus (MA) lineages introduced there. Phylogenetic relationships inferred between them implicate the plesiomorhic character of Da*Vr, Da*D? and Da-s6 haplotypes that were resolved as ancestral clades, with the intermediate position between clades holding haplotypes of the non-Danubian lineage and more advanced haplotypes of the Danubian lineage. A uniform rate of evolution was found for all clades. The recent widespread distribution and exclusivity of Da1 haplotype imply its ancestral character among advanced Danubian haplotypes. Populations in the Sava, Drava, Una and Drina revealed an expansion, whereas those in the Kupa and Zapadna Morava catchments revealed both stability in size and great differentiation. Gene flow between stocks was found to be negligible. 相似文献
7.
Synopsis We studied the reproductive behavior of wild caught and captive-born, first generation offspring of the Lake Malawi fish, Tramitichromis intermedius(Teleostei, Cichlidae), held in aquaria. Spawning behavior includes an exchange of actions with dominant males performing bower construction and courtship behaviors while females focus on oviposition and mouthbrooding. Egg counts per oviposition and brooding and interbrooding periods of wild caught T. intermedius follow records of other mouthbrooding cichlid fishes. Observation of circling behavior suggests this behavioral trait may be used in mate choice as longer circling, indicating a secure territory and thus male dominance, leads to more oviposition events and hence the potential for larger broods. Comparisons of clutch size and total length of young at release from full-sized females vs. first spawners reveal smaller clutches and young from the younger females, most likely stemming from differences in body size. Investigation of spawning photoperiodicity also noted distinctions between the two groups with wild caught T. intermedius spawning activity peaking in the middle of the light cycle and captive-born, first spawners exhibiting no significant peak in activity. The trend to spawn midday is most likely influenced by predation factors, while the lack of a spawning periodicity in the offspring may be explained by developmental processes, the absence of environmental cues or the tendency for smaller males to be opportunistic in spawning events. The details of spawning behavior recorded in this study provide a database to investigate species differences and to indicate changes due to chemical and physical disturbances. 相似文献
8.
M. E. Maklakova I. A. Kondratieva E. S. Mikhailova R. V. Stupin Sh. Yu. Khapchaev A. O. Kasumyan 《Journal of Ichthyology》2011,51(11):1133-1142
Effect of three- and fivefold intramuscular injections of antibiotics oxytetracyclin hydrochloride and benzylpenicillin sodium
(20 mg/kg) on immunophysiological status of juveniles of rainbow trout Parasalmo (=Oncorhynchus) mykiss (pathomorphological evaluation of internal organs, determination of the number of different types of leucocytes in the blood,
and electrophoretic investigation of protein profile of the blood serum) was investigated. It was determined that both antibiotics
cause neutropenia, removal of albumin fraction in the blood serum, and appearance of lipoid assemblages and different pathologies
of internal organs. Taste attractiveness of oxytetracyclin hydrochloride, benzylpenicillin sodium, cefazolin-akos, and neomycin
sulfate at the concentration in artificial food pellets of 1, 10, and 100 mg/ml was evaluated. It was determined that neomycin
sulfate has more preferable taste for fishes, cefazolin-akos is less attractive, and reaction of fishes to oxytetracyclin
hydrochloride and benzylpenicillin sodium depends on their concentration. The presence of two strongly different behavioral
stereotypes of testing of food taste was confirmed. 相似文献
9.
A video camera inside an underwater housing was used to record the spawning activities of lake trout, Salvelinus namaycush, in Kushog Lake, Ontario (Canada). Contrary to the commonly accepted belief describing lake trout as the only salmonine to
spawn exclusively at night, the recordings were taken during the day. Lake trout spawning behaviour is described in detail
and compared with other salmonine species. The loss of female “nest-building” and assumption of a novel itinerant strategy
during which females travel across the breeding grounds accompanied by a group of males, is considered to be an important
change in the evolution of the lake trout’s unique mode of spawning. 相似文献
10.
Sexual reproduction of the brooding sponge <Emphasis Type="Italic">Rhopaloeides odorabile</Emphasis>
Sexual reproduction of Rhopaloeides odorabile, a common Great Barrier Reef sponge, was quantified using histological sections from samples collected over two reproductive
seasons. Rhopaloeides odorabile is viviparous and gonochoristic with a male biased sex ratio (2.5:1). Commencement and cessation of gametogenesis coincides
with rising and falling sea surface temperatures (≈24–29°C). Spermatogenesis occurs from October until January. Females initiate
oogenesis in September with the asynchronous development of oocytes, embryos and larvae occurring within the brood chambers.
A larval release period of 5–6 weeks occurs during January and February. The minimum size of reproductive individuals was
176 cm3 for females and 192 cm3 for males. The total reproductive output for both sexes shows a positive correlation with size. A relative reproductive output
index quantified the maximum reproductive investment at approximately 1 and 3% of the total choanoderm for females and males,
respectively, which represents a lower range of reproduction in comparison to other viviparous sponges. Low reproductive output
in R. odorabile may be offset by an extended spawning period, alleviating the risk of releasing larvae in potentially adverse conditions
via one synchronised spawning event and increasing overall larval survival. 相似文献
11.
Katsuya Ichinose Luis C. Forti Denis R. Pretto Gösta Nachman Jacobus J. Boomsma 《Ecological Research》2007,22(2):288-295
Logistic regression analysis was used to analyse sex allocation in a population of the leaf-cutting ant Acromyrmex
balzani occurring in a pasture in southern Brazil. The field sample consisted of 151 fungus-garden chambers (18 queenright and 133
queenless), belonging to 50 nests with three vertically stacked chambers per nest on average. Taking nest chamber as the unit
of analysis, seven predictor variables were considered: sampling date, chamber depth, chamber volume, weight of fungus garden,
presence of a queen, number of large workers, and number of small to medium workers. The population-level numerical proportion
of females was 0.548 and the inferred proportional energetic investment in females 0.672. The former was not significantly
different from 0.5 (P=0.168), but the latter was (P=0.0003). The proportional investment in females per fungus garden increased with the number of large workers present (P=0.0002) and decreased with the dry weight of the fungus garden (P=0.012). This implies that resource acquisition through foraging is likely to be a major proximate determinant of sex allocation.
The negative correlation between female bias and fungus garden weight might be due to developing adult females requiring more
food than males, but this hypothesis could not be confirmed by direct statistical evidence. 相似文献
12.
Jessica H. Arbour Patricia Avendaño Jeffrey A. Hutchings 《Environmental Biology of Fishes》2010,87(4):353-362
The Alligatorfish (Aspidophoroides monopterygius) is one of numerous non-commercial marine fishes for which basic elements of life history and biology are poorly known. More
than 200 individuals were collected from the southern Gulf of St. Lawrence, Canada, in September 2000 and 2001, during fisheries-independent
surveys. The standard length of Alligatorfish averaged 10.9 cm in 2000 and 9.2 cm in 2001, and putative age ranged between
2 and 7 years. Males possessed significantly longer pelvic fins, relative to body size, than females. We hypothesize that
Alligatorfish undergo internal gametic association and that spawning takes place in mid- to late-autumn. Diet was comprised
primarily of amphipods and isopods; other diet items included euphausiids, mysids, copepods, pteropods and calcareous algae.
Based on analysis of individuals collected in 2000, 6.8% were affected by parasites (nematodes). Our research on the life
history and ecology of Alligatorfish contributes to our knowledge of the biodiversity of Canada’s sub-Arctic marine fish fauna. 相似文献
13.
Michael H. Meeuwig Christopher S. Guy Wade A. Fredenberg 《Environmental Biology of Fishes》2011,90(4):367-378
Lacustrine-adfluvial bull trout, Salvelinus confluentus, migrate from spawning and rearing streams to lacustrine environments as early as age 0. Within lacustrine environments,
cover habitat provides refuge from potential predators and is a resource that is competed for if limiting. Competitive interactions
between bull trout and other species could result in bull trout being displaced from cover habitat, and bull trout may lack
evolutionary adaptations to compete with introduced species, such as lake trout, Salvelinus namaycush. A laboratory experiment was performed to examine habitat use and interactions for cover by juvenile (i.e., <80 mm total
length) bull trout and lake trout. Differences were observed between bull trout and lake trout in the proportion of time using
cover (F
1,22.6 = 20.08, P < 0.001) and bottom (F
1,23.7 = 37.01, P < 0.001) habitat, with bull trout using cover and bottom habitats more than lake trout. Habitat selection ratios indicated
that bull trout avoided water column habitat in the presence of lake trout and that lake trout avoided bottom habitat. Intraspecific
and interspecific agonistic interactions were infrequent, but approximately 10 times greater for intraspecific interactions
between lake trout. Results from this study provide little evidence that juvenile bull trout and lake trout compete for cover,
and that species-specific differences in habitat use and selection likely result in habitat partitioning between these species. 相似文献
14.
K. D. Simon Y. Bakar A. G. Mazlan C. C. Zaidi A. Samat A. Arshad S. E. Temple N. J. Brown-Peterson 《Environmental Biology of Fishes》2012,93(4):491-503
Various aspects of the reproductive biology of two archer fishes Toxotes chatareus and Toxotes jaculatrix were studied to describe gonad development, spawning season, sex ratio, and fecundity. Spawning season was assessed using
monthly changes in gonadosomatic index (GSI) and histological inspection of the gonads. Both species exhibit two modes of
oocytes; a mode of small primary growth oocytes and a single mode that increases with size as oocytes sequester vitellogenin
and undergo maturation, showing the synchronous oocyte development typical of total spawners. Based on GSI values and advanced
stages of oocyte maturity, T. chatareus and T. jaculatrix, females appear to spawn from November to December. The average fecundity of female T. chatareus was 55 000 ± 5538 eggs, and T. jaculatrix was 50 000 ± 3440 eggs; fecundity ranged from 20 000 to 150 000 eggs for both species, with relative fecundities of 600 to
1100 eggs/g body weight, and a mean value of 800 ± 32 for T. chatareus; relative fecundity ranged from 500 to 1100 with a mean value of 700 ± 23 for T. jaculatrix. Sex ratio, defined as the proportion of males to females, was 2.2 and 2.5 in T. chatareus and T. jaculatrix, respectively. The apparent abundance of males in samples could be due to females being positioned lower in the water column
and therefore being sampled less frequently. Our results indicate that in both species, spawning occurs between the months
of November and December during the monsoon season, which provides the mangrove coastal waters inhabited by these species
with an abundance of food resources and additional floodplain nursery habitat for larvae and juveniles. 相似文献
15.
Vesta Skrodenytė-Arbačiauskienė Nijolė Kazlauskienė Milda Zita Vosylienė Tomas Virbickas 《Central European Journal of Biology》2012,7(5):878-885
Experimental studies of infection transmission via water from infected to healthy fish were conducted. The dark-brown bacterial colonies typical for Aeromonas salmonicida on tryptone soya agar (TSA) have been isolated and counted (from 3.0±0.6×102 to 3.5±0.5×105 c.f.u. g−1) from the internal organs of naturally infected (NI) and experimentally infected (EI) perch and sea trout. No significant differences in dark-brown bacterial counts were detected between EI perch and EI sea trout. The assessment and comparison of the alterations of the biological parameters of EI European perch and sea trout with bacterium Aeromonas salmonicida subsp. salmonicida with naturally infected perch were conducted. No mortality was recorded in groups of EI perch and sea trout. Whereas, the mortality of NI perch (collected from the main sites of outbreak of disease) was observed from the second day of the experiments. Changes in morphophysiological parameters of EI perch and sea trout were similar. Different alterations in blood cell parameters of EI fish were observed, and the most noticeable was the decrease (P≤0.01) in white blood cell count (WBC) of EI perch and sea trout. Based on these results it can be deduced that there is infection transmission of bacterium A. salmonicida from European perch via water to other fish species. 相似文献
16.
We studied habitat choice, diet, food consumption and somatic growth of Arctic charr (Salvelinus alpinus) and brown trout (Salmo trutta) during the ice-covered winter period of a subarctic lake in northern Norway. Both Arctic charr and brown trout predominantly
used the littoral zone during winter time. Despite very cold winter conditions (water temperature <1°C) and poor light conditions,
both fish species fed continuously during the ice-covered period, although at a much lower rate than during the summer season.
No somatic growth could be detected during the ice-covered winter period and the condition factor of both species significantly
declined, suggesting that the winter feeding rates were similar to or below the maintenance requirements. Also, the species
richness and diversity of ingested prey largely decreased from summer to winter for both fish species. The winter diet of
Arctic charr <20 cm was dominated by benthic insect larvae, chironomids in particular, and Gammarus lacustris, but zooplankton was also important in December. G. lacustris was the dominant prey of charr >20 cm. The winter diet of brown trout <20 cm was dominated by insect larvae, whereas large-sized
trout mainly was piscivorous, feeding on juvenile Arctic charr. Piscivorous feeding behaviour of trout was in contrast rarely
seen during the summer months when their encounter with potential fish prey was rare as the small-sized charr mainly inhabited
the profundal. The study demonstrated large differences in the ecology and interactions of Arctic charr and brown trout between
the winter and summer seasons. 相似文献
17.
Hybridization with introduced species represents a serious threat to the persistence of many native fish populations. Brook
trout (Salvelinus fontinalis) have been introduced extensively throughout the native range of bull trout (S. confluentus) and hybridization has been documented in several systems where they co-exist and is seen as a significant threat to the
persistence of bull trout populations. We identified a group of diagnostic microsatellite loci to differentiate bull trout
and brook trout and then used these loci to examine the spatial distribution of hybrids in the Malheur River basin, Oregon
USA. In random samples of approximately 100 fish from each of three creeks we identified 181 brook trout, 112 bull trout and
14 hybrids. Although bull trout, brook trout and hybrids were found in all three creeks, they were not evenly distributed;
brook trout were primarily found in the lower sections of the creeks, bull trout further upstream, and hybrids in the areas
of the greatest overlap. One creek with a population of brook trout in a headwater lake provided an exception to this pattern;
brook trout were found distributed throughout the creek downstream of the lake. Several post-F1 hybrids were identified suggesting
that hybrids are reproducing in the Malher River Basin. Mitochondrial DNA analysis indicated that both female bull trout and
brook trout are involved in hybridization events. Analysis of population structure suggested that brook trout have established
multiple spawning populations within the Malheur system. Data presented in this study suggest that relative abundance of brook
trout and habitat quality are important factors to consider when evaluating the threat of hybridization to bull trout populations. 相似文献
18.
The fatty acid status of the total lipids was studied in smolts of the brown trout and the Atlantic salmon collected in summer in the Indera River (White Sea basin). Higher 18:3ω-3/18:2ω-6, ω-3/ω-6, and 20:4ω-6/18:2ω-6 ratios were found in smolts of the Atlantic salmon in comparison to smolts of the brown trout. A higher amount of essential fatty acid 18:2ω-6 and an increased ratio of the sum of polyunsaturated fatty acids to the sum of saturated fatty acids in smolts of brown trout were observed. We have registered the differences in the ratios of the fatty acids, including physiologically active ones, which indicated species-specific physiological and biochemical processes during smoltification. 相似文献
19.
America G. Valiente Francis Juanes Pablo Nuñez Eva Garcia-Vazquez 《Biological invasions》2010,12(3):451-462
Brown trout of German origin were introduced into Patagonian National Parks in 1905, where they acclimatized and underwent
population expansion endangering populations of native species like Galaxiidae. Spawning adults of two populations were sampled
in 2004. Their age, length-at-age and migratory behaviour were assessed from scale samples, as well as their variation at
the coding LDH-C1* and eight non coding microsatellite loci. Between-population differentiation for life history (spawning time, migratory
behaviour, length and weight at age) and reduced genetic variation were revealed. Based on genetic variation, effective population
size smaller than 50 individuals has been estimated for the founder stock, and its German origin has been genetically traced.
Flexibility in migratory behaviour and spawning time were identified as key factors conferring competitive advantage on those
brown trout populations. 相似文献
20.
Sexual dimorphism in body size and canine weaponry is commonly associated with high levels of male-male competition. When
group living species do not rely heavily on male-male competition for access to females, sperm competition may represent a
viable alternative strategy. Unlike most haplorhine primates, lemurs are typically monomorphic in body weight and canine height.
We assessed variability of body mass dimorphism and canine size dimorphism in brown lemurs using morphometric data from 3
populations in southeastern Madagascar: Eulemur fulvus rufus, E. albocollaris, and hybrids of the species. We found significant male-biased canine dimorphism in E. albocollaris in conjunction with body-size monomorphism. We observed similar patterns in the hybrids, but E. fulvus rufus exhibited significant female-biased size dimorphism and canine monomorphism. Testes volume was relatively high across study
populations. Thus, sperm competition appears to be strong in brown lemurs. E. albocollaris males combine sperm competition with large canines, but not higher body mass, indicating a difference in sexual strategy
from most lemurs. Patterns of body mass and canine size dimorphism are not uniform across brown lemur populations, indicating
that future work on these populations can explicitly test models that predict relationships between size dimorphism and various
types of competition. 相似文献