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  • Cyprinidae  (3)
  • Lough Neagh  (1)
  • Sovdeborgssjon  (1)
Document type
Keywords
Publisher
Years
  • 1
    Electronic Resource
    Electronic Resource
    Predation pressure from above: observations on the activities of piscivorous birds at a shallow eutrophic lake (1990)
    Springer
    Hydrobiologia 191 (1990), S. 223-231 
    Details
    ISSN: 1573-5117
    Keywords: piscivorous birds ; freshwater fish ; predation pressure ; environmental structure ; distribution ; Sovdeborgssjon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The foraging activities of piscivorous birds at a small eutrophic lake in southern Sweden were observed during the ice-free months of 1984. Species-specific patterns of abundance and distribution were apparent. Great crested grebes and red-breasted mergansers were present for periods of months and weeks, respectively, while grey herons, black-headed gulls and red kites made numerous shorter visits. Both cyprinids and percids were seen to be captured. Speculative calculations suggest that the amount of fish removed by the birds is significant when compared with that taken by the lake's piscivorous fish, constituting 34% of total consumption in summer and at 99% becoming by far the more important component in late autumn. The peculiar characteristics of this source of predation pressure and their implications for fish populations are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00026055
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Possible competitive interactions between overwintering tufted duck (Aythya fuligula (L.)) and fish populations of Lough Neagh, Northern Ireland: evidence from diet studies (1994)
    Springer
    Hydrobiologia 279-280 (1994), S. 377-386 
    Details
    ISSN: 1573-5117
    Keywords: Aythya fuligula ; Rutilus rutilus ; waterfowl ; Cyprinidae ; competition ; Lough Neagh
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The overwintering population of tufted duck (Aythya fuligula) on Lough Neagh, Northern Ireland, has varied over the last three decades, with numbers declining in the early 1980s but then increasing to former levels in the late 1980s. Population fluctuations of recently introduced roach (Rutilus rutilus) mirrored these trends. The present study explores the possibility that competition for benthic food resources is responsible for these changes by examining the diets of tufted duck, roach and other major fish species of the lake. Diet overlaps were generally high due to the common consumption of chironomid larvae. The diet of tufted duck overlapped most with that of roach because these two species were the only significant consumers of molluscs. This evidence provides further support for a tufted duck — roach competition hypothesis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00027869
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Interactions between the roach, Rutilus rutilus, and waterfowl populations of Lough Neagh, Northern Ireland (1992)
    Springer
    Environmental biology of fishes 33 (1992), S. 207-214 
    Details
    ISSN: 1573-5133
    Keywords: Cyprinidae ; Tufted duck ; Great crested grebe ; Competition ; Benthos ; Ligula intestinalis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Following the introduction of roach, Rutilus rutilus, to a large eutrophic lake in ca. 1973, a subsequent increase in the abundance of this cyprinid through the 1970s was accompanied by a decline in the numbers of one of the lake&s most abundant overwintering waterfowl, the tufted duck, Aythya fuligula, and an increase in overwintering piscivorous great crested grebes, Podiceps cristatus. We suggest that these contrasting trends are causally related and that competition for benthos and increased prey availability are the mechanisms responsible for the changes in the tufted duck and grebe populations respectively. In agreement with these hypotheses, a reduction in the roach population during the mid 1980s was accompanied by a recovery of tufted ducks and a decline of grebes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00002565
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Factors affecting prey selection by young bream Abramis brama and roach Rutilus rutilus: insights provided by parallel studies in laboratory and field (1988)
    Springer
    Environmental biology of fishes 21 (1988), S. 279-292 
    Details
    ISSN: 1573-5133
    Keywords: Cyprinidae ; Cladocera ; Copepoda ; Foraging behaviour ; Diel migration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Synopsis Prey selection by underyearling bream and roach was studied in both the laboratory and field. When presented with cladoceran and a more elusive copepod prey both fish species select against copepods, regardless of the relative prey sizes. However, the field diet of bream, but not roach, consistently includes a large proportion of copepods. The explanation for this discrepancy lies in the timing and location of foraging in the field. Bream foraging, unlike that of roach, is largely restricted to the hours of darkness and to the lowest stratum of the lake. The Microcrustacea of this stratum is depleted of cladocerans at night, because of vertical migration, and is relatively rich in copepods.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00000376
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    Paper (German National Licenses)
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