Mortality and physiological stress of year-classes of landlocked and migratory Atlantic salmon, brown trout and brook trout in acidic aluminium-rich soft water

1986 ◽  
Vol 30 (3-4) ◽  
pp. 751-756 ◽  
Author(s):  
B. O. Rosselind ◽  
O. K. Skogheim ◽  
F. Kroglund ◽  
E. Hoell

1960 ◽  
Vol 17 (5) ◽  
pp. 713-720 ◽  
Author(s):  
C. J. Kerswill

Atlantic salmon, smelt, alewives, shad, eastern brook trout, and introduced brown trout occur in waters that will be affected by the Passamaquoddy power project. The first four species are taken occasionally in herring weirs but total annual landed values did not exceed $6,000 in the period 1937 to 1956. Salmon and trout have high potential value for angling, subject to improvements in local river management.Construction of tidal power dams should overcome the present lack of typical estuarine conditions in the Passamaquoddy area and favour production of anadromous species. An improved sport fishery for sea-run trout could develop. Realization of the potential production of Atlantic salmon, alewives and shad, but possibly not sea-run trout, would depend on satisfactory access from the Bay of Fundy to the impounded areas.



1985 ◽  
Vol 27 (4) ◽  
pp. 433-440 ◽  
Author(s):  
Ruth Phillips ◽  
Peter E. Ihssen

Chromosome banding patterns obtained by silver staining (Ag-NORs) were analyzed in three species of Salmo (rainbow, brown trout, and Atlantic salmon) and three species of Salvelinus (brook trout, lake trout, and arctic char). In rainbow trout and Atlantic salmon the Ag-NORs were found at the secondary constrictions of a single chromosome pair, while in brown trout the Ag-NORs were found on the short arms of one or two of the two longest subtelocentric or acrocentric chromosome pairs. The location of the Ag-NORs was multichromosomal in the three Salvelinus species, occurring on one or both members of four to six different chromosome pairs in different individuals. The Ag-NOR sites were on the short arms of some acrocentric pairs and at the telomeres of other acrocentric pairs and one or two metacentric pairs. Chromomycin A3 positive bands were found at the same sites as the Ag-NORs in all species. In the species with multichromosomal location of Ag-NORs, polymorphisms in the size and location of the NORs were extremely common, so that almost every individual fish had a different pattern of Ag-NOR sites.Key words: banding, Salmo, Salvelinus, Ag-NORs, polymorphisms, nucleolar organizer.



Author(s):  
Benjamin H. Letcher ◽  
Keith H. Nislow ◽  
Matthew J O'Donnell ◽  
Andrew R. Whiteley ◽  
Jason A. Coombs ◽  
...  

Trout and salmon commonly coexist in stream networks. Exploring similarities and differences among species can help explain coexistence and invasive ability. Here, we describe spatial distribution, cohort strengths and size-at-age of three co-occurring species in a small stream network. Spatial distributions varied dramatically among species; native brook trout occupied all stream reaches, naturalized brown trout were found in the mainstem and lower portions of tributaries and fry-stocked Atlantic salmon were limited to the mainstem. Size-at-age also differed among species, Atlantic salmon were consistently the smallest, brook trout were intermediate in size and brown trout were the largest. Despite size differences, mean lengths of brook trout and brown trout were highly correlated among years. Cohort strengths varied considerably across years but were also highly correlated for the two trout species, suggesting strong environmental control on cohort strength and a reduced role for species interactions. At low densities, we observed strong negative effects of density on body sizes and weaker effects otherwise. Overall, these results suggest differences in spatial distribution combined with similarities in response to environmental variation contribute to species coexistence in this small steam network.



Author(s):  
Janhavi Marwaha ◽  
Per Johan Jakobsen ◽  
Sten Karlsson ◽  
Bjørn Mejdell Larsen ◽  
Sebastian Wacker

AbstractThe freshwater pearl mussel (Margaritifera margaritifera) is a highly host-specific parasite, with an obligate parasitic stage on salmonid fish. Atlantic salmon (Salmo salar) and brown trout (Salmo trutta f. trutta and Salmo trutta f. fario) are the only hosts in their European distribution. Some M. margaritifera populations exclusively infest either Atlantic salmon or brown trout, while others infest both hosts with one salmonid species typically being the principal host and the other a less suitable host. Glochidial abundance, prevalence and growth are often used as parameters to measure host suitability, with the most suitable host species displaying the highest parameters. However, it is not known if the degree of host specialisation will negatively influence host fitness (virulence) among different host species. In this study we examined the hypothesis that glochidial infestation would result in differential virulence in two salmonid host species and that lower virulence would be observed on the most suitable host. Atlantic salmon and brown trout were infested with glochidia from two M. margaritifera populations that use Atlantic salmon as their principal host, and the difference in host mortality among infested and control (sham infested) fish was examined. Higher mortality was observed in infested brown trout (the less suitable host) groups, compared to the other test groups. Genetic assignment was used to identify offspring from individual mother mussels. We found that glochidia from individual mothers can infest both the salmonid hosts; however, some mothers displayed a bias towards either salmon or trout. We believe that the differences in host-dependent virulence and the host bias displayed by individual mothers were a result of genotype × genotype interactions between the glochidia and their hosts, indicating that there is an underlying genetic component for this parasite-host interaction.





2017 ◽  
Vol 40 (10) ◽  
pp. 1299-1307
Author(s):  
R Knudsen ◽  
E H Henriksen ◽  
K Ø Gjelland ◽  
H Hansen ◽  
D K Hendrichsen ◽  
...  
Keyword(s):  


Aquaculture ◽  
2004 ◽  
Vol 230 (1-4) ◽  
pp. 81-88 ◽  
Author(s):  
Fernando Ayllon ◽  
Jose L. Martinez ◽  
Patrick Davaine ◽  
Edward Beall ◽  
Eva Garcia-Vazquez


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