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  • Artikel: DFG Deutsche Nationallizenzen  (17)
  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Reviews in fish biology and fisheries 5 (1995), S. 461-473 
    ISSN: 1573-5184
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1573-5168
    Schlagwort(e): brook trout ; condition factor ; nucleic acids ; nutritional status ; protein ; Salvelinus fontinalis ; starvation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract To be useful as short-term indices of nutritional status when food availability varies, wet weight-at-length and tissue concentrations of nucleic acids and protein must covary closely with a fish's recent feeding history. We measured changes in these indices for young brook trout (Salvelinus fontinalis) (fork length: 20–34 mm) reared under alternating, 4 to 5 d periods of food provisioning and food deprivation. Weight-at-length corresponded closely with current feeding conditions, being higher when the trout were fed than when they were deprived. Concentrations of RNA and protein, however, did not correspond closely with current feeding conditions. Instead, there were significant carry-over effects whereby responses to feeding conditions experienced in one treatment period were not exhibited until the following treatment period. Food provisioning had positive carry-over effects on concentrations of RNA and protein while food deprivation had negative carry-over effects. Consequently, food-deprived trout sometimes had higher concentrations of RNA and protein than well fed trout. Since wild fish may experience short-term fluctuations in food availability, lagged responses in concentrations of nucleic acids or protein like those reported here could hamper attempts to use these biochemical measures to assess the nutritional status of juvenile fish in the field.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 26 (1988), S. 53-67 
    ISSN: 1573-4927
    Schlagwort(e): hatching time ; allozymes ; genetic variation ; fitness ; electrophoresis ; salmonid fishes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The hatching distributions of rainbow trout (Salmo gairdneri) with different genotypes at eight loci are compared in two experiments with the same strain. Embryos were incubated at temperatures colder (5 and 8°C) and warmer (12°C) than normally experienced by these fish (9.5°C). At hatching, embryos were separated into five hatching groups representing the chronological order of hatching. There is no significant correlation between multilocus heterozygosity and hatching time at any temperature in either experiment. Fish in the middle of the hatching distribution had the highest average heterozygosity. In both experiments, heterozygotes at the majority of loci examined tended to hatch relatively later within the hatching distribution at 12°C than at both 5 and 8°C. Fish with different genotypes atPgm2 andCk1 showed significant differences in hatching time that were consistent between experiments.Ck1 heterozygotes hatched sooner than homozygotes at 8°C but later at 12°C.Pgm2 heterozygotes hatched later than homozygotes at all temperatures and significantly later in four of five cases. At the other loci examined, however, the relative hatching distributions of fish with particular genotypes were not significantly different or repeatable between experiments.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Biochemical genetics 26 (1988), S. 69-81 
    ISSN: 1573-4927
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract The survival of rainbow trout (Salmo gairdneri) with different developmental rates and genotypes at eight polymorphic loci was compared in two experiments. The embryos were reared at temperatures colder (5 and 8°C) and warmer (12°C) than normally experienced by the strain (9.5°C). Embryo survival in five different hatching groups (representing the sequential order of hatching) was compared at 8 and 12°C. Embryos in the center of the hatching distribution (groups 2, 3, and 4) showed a greater survival to yolk sac resorption than those in the extremes (groups 1 and 5). These differences are significant in the embryos reared at 12°C in both experiments. Embryo survival from hatching to yolk sac resorption was poorer at 12 compared to 8°C. In the one experiment where it was examined, significantly fewer embryos hatched at 5 and 12 than at 8°C. Significant deviations from genotypic expectations (based upon parental allele frequencies) were detected in the progeny (23 of 34 cases). In contrast, few deviations from Hardy-Weinberg expectations were detected (5 of 34 cases) when progeny allele frequencies are used. Few significant differences in genotype frequencies were detected among the progeny reared at the different temperatures. This suggests that nonequal contributions of parental gametes rather than differential selection of genotypes account for the deviations from expectations in the progeny.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1573-4927
    Schlagwort(e): enzyme polymorphism ; developmental rate ; salmonid fishes ; viability ; natural selection ; gene duplication ; null alleles
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract We show that a previously described isozyme polymorphism in rainbow trout(Salmo gairdneri) is the result of an enzymatically inactive (i.e., null) allele(n). Ldh3 null homozygotes(n/n) and heterozygotes(100/n) have reductions of about 20 and 12% in total lactate dehydrogenase (LDH) activity at hatching, respectively. As juveniles,(100/n) fish have reductions in LDH activity of 15, 37, and 21% in brain, heart, and white muscle, respectively. Embryos with differntLdh3 phenotypes from 11 families do not differ significantly in either survival or hatching time. However, a second measure of developmental rate, the amount of malate dehydrogenase (MDH) and phosphoglucomutase (PGM) activity in 33-day-old embryos, suggests that(100/n) embryos develop more slowly than(100/100) embryos. In three of four families examined,(100/n) embryos have significantly lower amounts of total MDH activity (8–10%). In one of these,(100/n) embryos also have significantly lower total PGM activity (15%). These data suggest that the reduction in total LDH activity is associated with small but detectable delays in developmental rate but nondetectable differences in survival to hatching.
    Materialart: Digitale Medien
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  • 6
    ISSN: 1573-3297
    Schlagwort(e): behavior genetics ; mobility ; positioning ; inheritance ; fish
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Psychologie
    Notizen: Abstract The inheritance of mobility and positioning characteristics of F1 and back-cross hybrids of lake charr (Salvelinus namaycush) and brook charr (S. fontinalis) was investigated. Hybrids showed a closer affinity to brook charr for mobility measurements in that they spent more total time stationary in periods of longer duration than did the lake charr. This suggests either a directional dominance or a response to water flow. Lake, brook, and reciprocal hybrid charr held mean positions within the central section of the water column and did not vary significantly from each other in their mean vertical positions. However, there were significant differences in mean horizontal coordinates across charr types in that lake charr and F1 hydrids occupied positions midway along a laboratory stream channel, while brook charr occupied downstream positions. Even though there were no significant differences between the parental species in either means or standard errors of vertical and horizontal positioning, hybrid phenotypes varied significantly from both parents. Reciprocal effects were observed for variability of horizontal positions. A bivariate ANOVA revealed that horizontal measures were of greater importance than vertical measures in discriminating between charr types. It is likely that both genetic and environmental factors are responsible for the characteristic differences in mobility and positioning between brook and lake charr.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Environmental biology of fishes 36 (1993), S. 215-217 
    ISSN: 1573-5133
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    Environmental biology of fishes 8 (1983), S. 151-156 
    ISSN: 1573-5133
    Schlagwort(e): Social behaviour ; Behaviour-genetics ; Food ; Water flow ; Population density ; Trout ; Salmonidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis Manipulation of water velocity, fish density and food ration produced few significant effects on the behaviour or social system of juvenile lake charr (Salvelinus namaycush). Individuals showed consistently low levels of agonistic behaviour and spent more time close to the substrate with increasing water velocity. The restricted behavioural plasticity and potential of this species is contrasted with the much greater range shown by the closely related brook charr (S. fontinalis).
    Materialart: Digitale Medien
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  • 9
    ISSN: 1573-5133
    Schlagwort(e): Growth ; Investment ; Life-history strategy ; Reproduction ; Salvelinus alpinus ; Oncorhynchus gorbuscha ; Salmonine fishes
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis RNA/DNA ratios were used to estimate recent somatic allocation of spawning arctic charr,Salvelinus alpinus, and pink salmon,Oncorhynchus gorbuscha. Smaller arctic charr morphs had lower ratios than larger morphs. Larger male pink salmon had lower ratios than smaller males. Thus recent somatic allocation (anabolic metabolic activity and growth) is coupled with cumulative lifetime growth in iteroparous arctic charr, but is uncoupled in semelparous pink salmon. These data suggest that somatic investment in these species is being differentially effected by the energetic costs of reproduction.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Environmental biology of fishes 20 (1987), S. 67-73 
    ISSN: 1573-5133
    Schlagwort(e): Electrophoresis ; Genetic differentiation ; Ecological polymorphism ; Salmonidae
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Synopsis The degree of genetic differentiation among four morphs of Arctic charr (small benthivorous, large benthivorous, piscivorous, and planktivorous) from Thingvallavatn, Iceland, was determined electrophoretically. Five of 36 enzyme loci were found to be polymorphic (Est2, Gpi3, Ldh4, Mdh4, 5 and Pgm2). However, only Est2 and Mdh4,5 showed enough variability to permit statistical analysis of divergence among morphs. All four morphs are very closely related; the values of Nei's (D) range from 0.00004 to 0.00126. These morphs are conspecific and do not represent different evolutionary lineages. There is significant genetic differentiation between the small benthivorous charr and the other three morphs. The relative relatedness of morphs based on gene frequency data is only partially concordant with that based on morphology and ecological specialization. The biological significance of this result is unclear because of the limited number of polymorphic loci upon which the genetic analysis is based and the high degree of relatedness among morphs.
    Materialart: Digitale Medien
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