Genetic analyses of European minnow,Phoxinus phoxinus, in a river system outside its native range indicate multiple invasions from different sources

2013 ◽  
Vol 21 (1) ◽  
pp. 75-81 ◽  
Author(s):  
J. Thaulow ◽  
R. Borgstrøm ◽  
M. Heun
Keyword(s):  
River System ◽  
Native Range ◽  
Genetic Analyses ◽  
Phoxinus Phoxinus ◽  
European Minnow ◽  
Multiple Invasions ◽  
Different Sources

scholarly journals The helminth fauna of brown trout (Salmo trutta) from a sub-alpine lake revisited after 40 years with introduced European minnow (Phoxinus phoxinus)

2021 ◽  
Vol 41 ◽  
pp. 15-26
Author(s):  
Reidar Borgstrøm ◽  
Øyvind Hatleli Mestrand ◽  
John E. Brittain ◽  
Leif Lien
Keyword(s):  
Brown Trout ◽  
Salmo Trutta ◽  
Helminth Fauna ◽  
Helminth Species ◽  
Population Increase ◽  
Intermediate Hosts ◽  
Phoxinus Phoxinus ◽  
Piscivorous Birds ◽  
European Minnow ◽  
Brown Trout Salmo Trutta

The helminth fauna of brown trout (Salmo trutta) in the Norwegian subalpine lake, Øvre Heimdalsvatn was studied by examination of gills, eyes, body cavity, kidney, stomach, pyloric region and intestine in a total of 112 brown trout randomly sampled in June, July, and September 2011. Ten helminth species, Discocotyle sagittata, Phyllodistomum umblae, Crepidostomum farionis, C. metoecus, Diplostomum sp., Proteocephalus sp., Cyathocephalus truncatus, Dibothriocephalus ditremus, D. dendriticus, and Capillaria sp. were identified. These data were compared to data from the period 1969 to 1972, just after the first record of the European minnow (Phoxinus phoxinus) in 1969. All ten helminth species, except D. dendriticus, were also present in 1969–72. However, a few major changes in infection intensities have occurred. The cestode D. ditremus and the trematode Diplostomum sp., both with piscivorous birds as final hosts, had markedly higher relative densities (abundance) in brown trout in 2011 compared to 1969–72, while the two Crepidostomum species showed a substantial decline in relative densities. We suggest that these changes may be indirectly related to the establishment and subsequent population increase of European minnow in the lake. The abundance of minnows may have increased the food basis for the piscivorous birds, primarily mergansers and the black-throated diver that now regularly forage in the lake. In addition, there have been changes in the littoral invertebrate community, including species serving as intermediate hosts of some of the brown trout parasites.

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