scholarly journals Freshwater early life growth influences partial migration in populations of Dolly Varden (Salvelinus malma malma)

Polar Biology ◽  
2021 ◽  
Author(s):  
Christie M. Morrison ◽  
Colin P. Gallagher ◽  
Keith B. Tierney ◽  
Kimberly L. Howland
Keyword(s):  
Life History ◽  
Life History Theory ◽  
River System ◽  
Early Growth ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Mixed Effect ◽  
Seaward Migration ◽  
Northern Dolly Varden ◽  
And Migration

AbstractPopulations of northern Dolly Varden (Salvelinus malma malma) exhibit partial seaward migration, yet little is known about this phenomenon in Dolly Varden populations. Our study analyzed data from three different Dolly Varden populations in the western Canadian Arctic in order to determine if: (1) differences in size-at-first seaward migration exist between fish that migrate at early and late ages among populations inhabiting different river systems, and (2) annual growth influences anadromous or resident life history choice. Otolith strontium analysis and back-calculation were used to determine age- and size-at-first seaward migration, respectively. Differences in age- and size-at-first seaward migration were determined across river system and migration age. Back-calculated fish lengths were compared using a mixed effect model to determine how early growth influences migratory tactics (early or late aged smolt, or resident). Our results indicate that fish exhibiting faster early growth migrated in earlier years and at smaller sizes than slower growing fish, however size- and age-at first seaward migration varied by river system. Faster growing Dolly Varden tended to become either residents or early smolts, while slower growth was associated with smolting later in life. This is contrary to life history theory where the fastest growing fish in a population should mature as a resident. Our results indicate factors other than growth may be influencing life history ‘decisions’ in Dolly Varden. Future work on growth efficiencies and metabolic rates is needed to assess how they affect migratory behaviours.

Life-history characteristics and landscape attributes as drivers of genetic variation, gene flow, and fine-scale population structure in northern Dolly Varden (Salvelinus malma malma) in Canada

2015 ◽  
Vol 72 (10) ◽  
pp. 1477-1493 ◽  
Author(s):  
Les N. Harris ◽  
Robert Bajno ◽  
Colin P. Gallagher ◽  
Itsuro Koizumi ◽  
Lucy K. Johnson ◽  
...  
Keyword(s):  
Population Structure ◽  
Genetic Variation ◽  
Life History ◽  
Gene Flow ◽  
Isolation By Distance ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Dolly Varden Salvelinus Malma ◽  
Northern Dolly Varden ◽  
Population Demographic

The northern Dolly Varden (Salvelinus malma malma) displays variable life-history types and occupies freshwater habitats with varying levels of connectivity. Here, we assayed microsatellite DNA variation in northern Dolly Varden from the western Canadian Arctic to resolve landscape and life-history variables driving variation in genetic diversity and population structure. Overall, genetic variation was highest in anadromous populations and lowest in those isolated above waterfalls, with stream-resident forms intermediate between the two. Anadromous and isolated populations were genetically divergent from each other, while no genetic differentiation was detectable between sympatric anadromous and stream-resident forms. Population structure was stable over 25 years, hierarchically organized, and conformed to an isolation-by-distance pattern, but stream-isolated forms often deviated from these patterns. Gene flow occurred primarily among Yukon North Slope populations and between sympatric anadromous and resident forms. These results were sex-dependent to some extent, but were influenced more by reproductive status and life history. Our study provides novel insights into the life history, population demographic, and habitat variables that shape the distribution of genetic variation and population structure in Arctic fluvial habitats while providing a spatial context for management and conservation.

Predation by River Otters (Lutra canadensis) on Juvenile Coho Salmon (Oncorhynchus kisutch) and Dolly Varden (Salvelinus malma) in Southeast Alaska

1993 ◽  
Vol 50 (2) ◽  
pp. 312-315 ◽  
Author(s):  
C. Andrew Dolloff
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
River System ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Southeast Alaska ◽  
River Otters ◽  
Juvenile Salmonids ◽  
Dolly Varden Salvelinus Malma ◽  
Lutra Canadensis

The effect of predation by river otters (Lutra canadensis) on juvenile coho salmon (Oncorhynchus kisutch) and Dolly Varden (Salvelinus malma) in a Southeast Alaska watershed was inferred by examining the number and size distribution of sagittal otoliths that were found in otter scats. Individual scats contained up to 408 otoliths, indicating that at least 200 fish had been eaten between defecations. Otoliths from juvenile salmonids outnumbered those from coastrange sculpins (Cottus aleuticus) by about six to one. Based on examination of over 8000 otoliths found in otter scats, at least 3300 juvenile salmonids were eaten by two river otters and their two young in the Kadashan River system during a 6-wk period in late spring 1985.

Northern Dolly Varden charr total mercury concentrations: variation by life-history type

Hydrobiologia ◽  
2016 ◽  
Vol 783 (1) ◽  
pp. 159-175 ◽  
Author(s):  
L. Tran ◽  
J. D. Reist ◽  
M. Power
Keyword(s):  
Life History ◽  
Total Mercury ◽  
Dolly Varden ◽  
Northern Dolly Varden

Morphophysiological patterns of life history strategy adoption in Dolly Varden Salvelinus malma in Kamchatka

2017 ◽  
Vol 57 (5) ◽  
pp. 688-705 ◽  
Author(s):  
M. A. Gruzdeva ◽  
K. V. Kusishchin ◽  
E. D. Pavlov ◽  
A. G. Bush ◽  
N. V. Belova ◽  
...  
Keyword(s):  
Life History ◽  
Life History Strategy ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Dolly Varden Salvelinus Malma

Resource partitioning as a factor limiting gene flow in hybridizing populations of Dolly Varden char (Salvelinus malma) and bull trout (Salvelinus confluentus)

2001 ◽  
Vol 58 (10) ◽  
pp. 2037-2047 ◽  
Author(s):  
John Hagen ◽  
Eric B Taylor
Keyword(s):  
Life History ◽  
Gene Flow ◽  
Secondary Contact ◽  
Life History Stage ◽  
Bull Trout ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Salvelinus Confluentus ◽  
Dolly Varden Char ◽  
Northwestern North America

Dolly Varden char (Salvelinus malma) and bull trout (Salvelinus confluentus) hybridize in areas of secondary contact in northwestern North America but maintain their genetic integrity in spite of gene flow. We examined juvenile stream ecology and adult reproductive ecology of these species in sympatry to test for specializations to alternative niches that may act as a basis for natural selection against hybrids. Juvenile Dolly Varden occupied deeper, faster water and foraged more during daytime in the drift, whereas bull trout used shallower, slower water and made more nighttime foraging attempts towards the substrate. The species showed extensive diet overlap (Schoener's index = 0.7–0.9), and we found evidence for density compensation between species among sites. Our results suggest no obvious basis for selection against hybrids at the juvenile stream-rearing life-history stage. Bull trout, however, are adfluvial, whereas Dolly Varden are permanent stream residents. Bull trout are also much larger at maturity (50–80 cm vs. 12–15 cm) and build redds in faster, deeper water using larger substrate sizes. Consequently, hybrid genotypes may be selected against in these alternative life-history niches or during reproduction owing to their intermediate size at maturity and size-dependent spawning habitat use and mate choice.

Summer growth patterns of northern Dolly Varden (Salvelinus malma) smolts from the Prudhoe Bay region of Alaska

1997 ◽  
Vol 54 (5) ◽  
pp. 1103-1110 ◽  
Author(s):  
R G Fechhelm ◽  
J D Bryan ◽  
W B Griffiths ◽  
L R Martin
Keyword(s):  
Prey Availability ◽  
Late Summer ◽  
Early Summer ◽  
Growth Patterns ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Dolly Varden Salvelinus Malma ◽  
Northern Dolly Varden ◽  
Stock Mixing ◽  
Rates Of Growth

Summer length growth patterns of northern Dolly Varden (Salvelinus malma) smolts from the Sagavanirktok River, northern Alaska, were analyzed for the years 1985-1994 and found to be sigmoidal, indicating slow rates of growth in early and late summer with the most rapid growth occurring in midseason. Nonlinear logistic regression functions of mean cohort length against date provided a reasonable fit of the data for all years except for 1991, accounting for more than 94% (r2 values ranged from 0.95 to 0.99) of the variation in mean daily length in any given year. Slow growth in early summer is in direct contrast with the growth patterns reported for juvenile broad whitefish (Coregonus nasus) and Arctic cisco (C. autumnalis) which inhabit the Sagavanirktok River and estuary. Some possible explanations for the observed Dolly Varden growth patterns include migration, dispersal, prey availability, water quality, and stock mixing.

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