Unidirectional Natural Hybridization between Brown Trout (Salmo trutta) and Atlantic Salmon (S. salar) in Newfoundland

1992 ◽  
Vol 49 (9) ◽  
pp. 1953-1958 ◽  
Author(s):  
Colin McGowan ◽  
William S. Davidson

Protein electrophoresis and mitochondrial DNA analysis were used to detect the frequency and direction of natural hybridization between brown trout (Salmo trutta) and Atlantic salmon (S. salar) in nine Newfoundland rivers. In total, 37 hybrids were discovered in a sample of 792 juvenile fish for a regional frequency of 4.67%. Local frequencies ranged from 0.00 to 18.75% and were significantly heterogeneous. All of the hybrids sampled were produced from matings between female brown trout and male Atlantic salmon. Possible reasons for the breakdown of prereproductive isolating mechanisms between these species are considered. Reproductive characteristics of the populations involved appear to have a major influence on the dynamics of hybridization between these species in Newfoundland. It is proposed that an abundance of sexually mature Atlantic salmon parr in Newfoundland streams is responsible for both the frequency and direction of hybridization observed in this study.

Author(s):  
Anna Hagelin ◽  
Eva Bergman

Abstract Worldwide declines in salmonid populations have generated major interest in conservation and restoration of wild populations and riverine habitats. Species reintroductions to previous habitats raises questions about their potential impact on these systems. In River Klarälven, landlocked Atlantic salmon (Salmo salar) has been extinct from upper reaches for over 50 years due to hydropower dams. Here we study competitive interactions between salmon, grayling (Thymallus thymallus) and brown trout (Salmo trutta), that occur in the upper reaches of the river. We examine foraging rates, aggression and activity of juvenile fish in allopatry at three different densities and in sympatry with one or both potential competitors in laboratory flumes. Salmon captured prey less frequently in the presence of brown trout and grayling, whereas grayling and brown trout were unaffected by salmon, but affected each other. Grayling was the most aggressive and active species whereas salmon the least. Consequently, re-introduction of salmon probably will have little impact on grayling and brown trout, whereas grayling and brown trout could affect the success of re-introducing salmon.


2011 ◽  
Vol 20 (4) ◽  
pp. 548-557 ◽  
Author(s):  
Linnea Lans ◽  
Larry A. Greenberg ◽  
Jens Karlsson ◽  
Olle Calles ◽  
Monika Schmitz ◽  
...  

2002 ◽  
Vol 293 (2) ◽  
pp. 106-118 ◽  
Author(s):  
Christian K�lb�k Tipsmark ◽  
Steffen S�ndergaard Madsen ◽  
Michel Seidelin ◽  
Akim Stypinsky Christensen ◽  
Christopher Paul Cutler ◽  
...  

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