Age, Food, and Migration of Dolly Varden Smolts in Southeastern Alaska

1970 ◽  
Vol 27 (6) ◽  
pp. 991-1004 ◽  
Author(s):  
Robert H. Armstrong
Keyword(s):  
Coho Salmon ◽  
Pink Salmon ◽  
Age Groups ◽  
Fork Length ◽  
Oncorhynchus Keta ◽  
Dolly Varden ◽  
Food Items ◽  
Dolly Varden Salvelinus Malma ◽  
High Return ◽  
And Migration

Dolly Varden (Salvelinus malma) smolts were enumerated and sampled in 1967, 1968, and 1969 at Hood Bay Creek, a nonlake system on Admiralty Island, and in 1962, 1963, and 1964 at Eva Lake, on Baranof Island.Dolly Varden smolts left Hood Bay Creek from early May to late June and from early September to mid-November. At Eva Lake, a smolt migration occurred in May and June but not during the fall. Most of the smolts at Hood Bay Creek belonged to age-groups II, III, and IV and at Eva Lake to age-groups III and IV. Smolts from the two systems were similar in size, varying from 100 to 180 mm in fork length, with annual mean lengths ranging from 134 to 136 mm.Insects and fry of chum (Oncorhynchus keta) and pink salmon (O. gorbuscha) were the principal food items of Dolly Varden and coho salmon (O. kisutch) smolts sampled at the Hood Bay Creek weir in May and June. Dolly Varden smolts leaving Hood Bay Creek in the fall fed primarily on salmon eggs, whereas insects were the principal food items of smolts sampled at the Eva Lake weir.Suggestions for management of Dolly Varden are given. The number of eggs, fry, or smolts necessary to maintain a given run of Dolly Varden indicates a high return from smolts and a low return from eggs or fry. Transplanting smolts from one system to another to establish or enhance a population in a depleted system is suggested.

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.

scholarly journals Effects of subsidies from spawning chum and pink salmon on juvenile coho salmon body size and migration timing

Ecosphere ◽  
2015 ◽  
Vol 6 (10) ◽  
pp. art209-art209 ◽  
Author(s):  
Michelle C. Nelson ◽  
John D. Reynolds
Keyword(s):  
Body Size ◽  
Coho Salmon ◽  
Pink Salmon ◽  
Migration Timing ◽  
And Migration

Pacific salmon (Oncorhynchus spp.) runs and consumer fitness: growth and energy storage in stream-dwelling salmonids increase with salmon spawner density

2012 ◽  
Vol 69 (1) ◽  
pp. 73-84 ◽  
Author(s):  
Daniel J. Rinella ◽  
Mark S. Wipfli ◽  
Craig A. Stricker ◽  
Ron A. Heintz ◽  
Matthew J. Rinella
Keyword(s):  
Growth Rate ◽  
Energy Density ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Nutritional Ecology ◽  
Dolly Varden ◽  
South Central ◽  
Dolly Varden Salvelinus Malma ◽  
N Enrichment

We examined how marine-derived nutrients (MDN), in the form of spawning Pacific salmon, influenced the nutritional status and δ15N of stream-dwelling fishes. We sampled juvenile coho salmon ( Oncorhynchus kisutch ) and Dolly Varden ( Salvelinus malma ) during spring and fall from 11 south-central Alaskan streams that ranged widely in spawning salmon biomass (0.1–4.7 kg·m–2). Growth rate (as indexed by RNA–DNA ratios), energy density, and δ15N enrichment in spring-sampled fishes increased with spawner biomass, indicating the persistence of spawner effects more than 6 months after salmon spawning. Point estimates suggest that spawner effects on nutrition were substantially greater for coho salmon than Dolly Varden (268% and 175% greater for growth and energy, respectively), indicating that both species benefitted physiologically, but that juvenile coho salmon accrued more benefits than Dolly Varden. Although the data were less conclusive for fall- than spring-sampled fish, they do suggest spawner effects were also generally positive during fall, soon after salmon spawned. In a follow-up analysis where growth rate and energy density were modeled as a function of δ15N enrichment, results suggested that both increased with MDN assimilation, especially in juvenile coho salmon. Our results support the importance of salmon runs to the nutritional ecology of stream-dwelling fishes.

Climate-induced trends in predator–prey synchrony differ across life-history stages of an anadromous salmonid

2017 ◽  
Vol 74 (9) ◽  
pp. 1431-1438 ◽  
Author(s):  
Donovan A. Bell ◽  
Ryan P. Kovach ◽  
Scott C. Vulstek ◽  
John E. Joyce ◽  
David A. Tallmon
Keyword(s):  
Climate Change ◽  
Life History ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Upstream Migration ◽  
Dolly Varden ◽  
Predator Prey ◽  
Life History Stages ◽  
Dolly Varden Salvelinus Malma

Differential climate-induced shifts in phenology can create mismatches between predators and prey, but few studies have examined predator–prey mismatch across multiple life-history stages. We used long-term data from a warming stream with shifting salmonid migration timings to quantify intra-annual migration synchrony between predatory Dolly Varden (Salvelinus malma) and Pacific salmon prey and examined how predator–prey synchrony has been influenced by climate change. We demonstrate that Dolly Varden have become increasingly mismatched with spring downstream migrations of abundant pink salmon (Oncorhynchus gorbuscha) juveniles. However, Dolly Varden have remained matched with fall upstream migrations of spawning Pacific salmon, including coho (Oncorhynchus kisutch), sockeye (Oncorhynchus nerka), and pink salmon. Downstream predator–prey migration synchrony decreased over time and with higher temperatures, particularly with pink salmon. In contrast, upstream migration synchrony was temporally stable and increased with rising temperatures. Differing trends in Dolly Varden predator–prey synchrony may be explained by the direct use of salmon to cue upstream migration, but not downstream migration. Overall, we show that climate change can have differing impacts on predator–prey synchrony across life-history stages.

Microhabitat Partitioning among Stream-Dwelling juvenile Coho Salmon, Oncorhynchus kisutch, and Dolly Varden, Salvelinus malma

1990 ◽  
Vol 47 (12) ◽  
pp. 2297-2306 ◽  
Author(s):  
C. Andrew Dolloff ◽  
Cordon H. Reeves
Keyword(s):  
Habitat Use ◽  
Coho Salmon ◽  
Focal Point ◽  
Oncorhynchus Kisutch ◽  
The Other ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Fish Size ◽  
Dolly Varden Salvelinus Malma ◽  
Natural Streams

Microhabitat use and partitioning among age 0+ and 1+ coho salmon, Oncorhynchus kisutch, and age 0+, 1+ and 2+ Dolly Varden, Salvelinus malma, was studied in small (<2 m wide), natural streams on Prince of Wales Island, Alaska, and in laboratory stream channels. Coho salmon occupied midwater positions that they defended from other fish. Dolly Varden were more closely associated with the stream bottom and were seldom territorial. For each species, the depth of water, depth of focal point, and distance to nearest fish increased with fish size, whereas the distance to nearest cover decreased as fish size increased. Most fish selected focal point velocities between 0.0–9.0 cm∙s−1.Woody debris was the most frequently used cover type and most fish occurred over gravel substrates ranging from 2–100 mm particle diameter. Habitat use by each species in the laboratory was similar to the pattern observed in the field. Each species occupied similar habitats both when alone and when the other species was present. Although habitat use by juveniles of coho salmon and Dolly Varden overlapped among several key parameters, each species primarily exploited resources not readily available to or selected by the other in the natural streams we studied.

Fecundity of Resident and Anadromous Dolly Varden (Salvelinus malma) in Southeastern Alaska

1973 ◽  
Vol 30 (4) ◽  
pp. 543-548 ◽  
Author(s):  
R. F. Blackett
Keyword(s):  
Egg Size ◽  
Fish Length ◽  
Dolly Varden ◽  
Salvelinus Malma ◽  
Ovary Weight ◽  
Dolly Varden Salvelinus Malma ◽  
Egg Number ◽  
Unit Of Length ◽  
The Right ◽  
Linear Regressions

Fecundity of resident Dolly Varden (Salvelinus malma) in an isolated population of southeastern Alaska averaged 66 eggs per female in comparison with 1888 eggs for anadromous Dolly Varden from two nearby streams. A relatively large egg size, averaging 3.6 mm in diameter and overlapping the range for the anadromous char, has been retained by the females in the resident population. Curvilinear regressions between egg number and fish length and linear regressions between egg number and body and ovary weights show that resident females have fewer eggs per unit of length, approximately the same number of eggs per gram of body weight, and more eggs per gram of ovary weight than anadromous females. The resident char attain sexual maturity a year earlier in life and at a smaller size than the migratory char. Development of a larger left ovary containing more eggs than the right was a common occurrence for both resident and anadromous Dolly Varden.

Families, Relationships, and Technology

2021 ◽  
Author(s):  
Raelene Wilding
Keyword(s):  
Digital Media ◽  
Family Life ◽  
Social Transformation ◽  
Age Groups ◽  
Aged Care ◽  
Cultural Norms ◽  
Rapid Changes ◽  
And Migration ◽  
The Life Course ◽  
Family Connection

Digital media are transforming families and relationships. Whether these changes are best thought of as positive or negative needs to be considered within a larger context of social transformation, in which changing gender roles and labor markets, cultural norms of intimacy and relationships, and globalization and migration are also contributing to rapid changes in family life. Drawing on recent theoretical developments that emphasize family as a set of practices and digital media as simultaneously social and technological, this chapter considers the intersections of family and technology across the life course, from partnering to pregnancy and adoption to parenting, family support, and aged care. The evidence suggests a mixed impact of digital media on family life. The popularity of digital media suggests that there is a strong desire for families to remain in touch and that people use digital media to maintain strong bonds of intimacy and family connection, even when circumstances require them to live at a distance. In some cases, access to digital media is contributing to the democratization of relationships across gender, class, and age groups. At the same time, it appears that digital media are also capable of both reinforcing existing inequalities and generating new asymmetries of power. To illustrate these complex trends, examples are drawn from a rich and growing body of research on how families are using digital media around the world and with what consequences, including the experiences of migrants and refugees.

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