scholarly journals Effects of spawning Pacific salmon on terrestrial invertebrates: Insects near spawning habitat are isotopically enriched with nitrogen‐15 but display no differences in body size

2021 ◽  
Vol 11 (18) ◽  
pp. 12728-12738
Author(s):  
Nicola F. Rammell ◽  
Allison M. Dennert ◽  
Christopher M. Ernst ◽  
John D. Reynolds
Keyword(s):  
Body Size ◽  
Pacific Salmon ◽  
Spawning Habitat ◽  
Terrestrial Invertebrates

Pacific Salmon: Ecology and Management of Western Alaska’s Populations

2009 ◽  
Keyword(s):  
Food Source ◽  
Driving Forces ◽  
Pacific Salmon ◽  
Late Summer ◽  
Terrestrial Ecosystems ◽  
Food Resources ◽  
Growth And Survival ◽  
Terrestrial Invertebrates ◽  
Riverine Ecosystems ◽  
Aquatic Food

<em>Abstract.</em>—Much is known about the importance of the physical characteristics of salmonid habitat in Alaska and the Pacific Northwest, with far less known about the food sources and trophic processes within these habitats, and the role they play in regulating salmonid productivity. Freshwater food webs supporting salmonids in Alaska rely heavily on nutrient, detritus, and prey subsidies from both marine and terrestrial ecosystems. Adult salmon provide a massive input of marine biomass to riverine ecosystems each year when they spawn, die, and decompose, and are a critical food source for young salmon in late summer and fall; riparian forests provide terrestrial invertebrates to streams, which at times comprise over half of the food ingested by stream-resident salmonids; up-slope, fishless headwater streams are a year-round source of invertebrates and detritus for fish downstream. The quantity of these food resources vary widely depending on source, season, and spatial position within a watershed. Terrestrial invertebrate inputs from riparian habitats are generally the most abundant food source in summer. Juvenile salmonids in streams consume roughly equal amounts of freshwater and terrestrially-derived invertebrates during most of the growing season, but ingest substantial amounts of marine resources (salmon eggs and decomposing salmon tissue) when these food items are present. Quantity, quality, and timing of food resources all appear to be important driving forces in aquatic food web dynamics, community nutrition, and salmonid growth and survival in riverine ecosystems.

The ecology of terrestrial invertebrates on Pacific salmon carcasses

2009 ◽  
Vol 24 (5) ◽  
pp. 1091-1100 ◽  
Author(s):  
Morgan D. Hocking ◽  
Richard A. Ring ◽  
Thomas E. Reimchen
Keyword(s):  
Pacific Salmon ◽  
Terrestrial Invertebrates ◽  
Salmon Carcasses

Changes in body size of Canadian Pacific salmon over six decades

2017 ◽  
Vol 74 (2) ◽  
pp. 191-201 ◽  
Author(s):  
Kyla M. Jeffrey ◽  
Isabelle M. Côté ◽  
James R. Irvine ◽  
John D. Reynolds
Keyword(s):  
Body Size ◽  
Sockeye Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Southern Oscillation ◽  
Rapid Change ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Evolutionary Response

Body size can sometimes change rapidly as an evolutionary response to selection or as a phenotypic response to changes in environmental conditions. Here, we revisit a classic case of rapid change in body size of five species of Pacific salmon (Oncorhynchus spp.) caught in Canadian waters, with a six-decade analysis (1951–2012). Declines in size at maturity of up to 3 kg in Chinook (Oncorhynchus tshawytscha) and 1 kg in coho salmon (Oncorhynchus kisutch) during the 1950s and 1960s were later reversed to match or exceed earlier sizes. In contrast, there has been little change in sockeye salmon (Oncorhynchus nerka) sizes and initial declines in pink (Oncorhynchus gorbuscha) and chum salmon (Oncorhynchus keta) sizes have halted. Biomass of competing salmon species contributed to changes in size of all five species, and ocean conditions, as reflected by the North Pacific Gyre Oscillation and the Multivariate ENSO (El Niño – Southern Oscillation) indices, explained variation in four of the species. While we have identified a role of climate and density dependence in driving salmon body size, any additional influence of fisheries remains unclear.

Model for Examining Early Ocean Limitation of Pacific Salmon Production

1978 ◽  
Vol 35 (10) ◽  
pp. 1303-1315 ◽  
Author(s):  
Carl J. Walters ◽  
Ray Hilborn ◽  
Randall M. Peterman ◽  
Michael J. Staley
Keyword(s):  
Body Size ◽  
Simulation Model ◽  
Marine Biology ◽  
Pacific Salmon ◽  
Juvenile Fish ◽  
Computer Simulation Model ◽  
Population Limitation ◽  
Near Surface ◽  
And Migration ◽  
Zooplankton Production

A computer simulation model was used to examine growth and survival of all major British Columbia salmon stocks during their first 6 mo of ocean life. Factors included in the calculations were the space–time distribution of zooplankton production, timing of salmon ocean arrival and migration especially as regards overlaps between stocks, feeding and growth in relation to food availability, and mortality rates in relation to body size. It is concluded that ocean limitation of production is unlikely unless only a small fraction of total zooplankton production is available to the salmon. The model emphasizes several critical uncertainties about the marine biology of salmon: rates of replenishment of near surface zooplankton stocks (where most salmon feeding occurs) from deeper water have not been adequately measured, and the functional response of salmon to prey density is not understood. There is inadequate data on the relationship between body size and mortality rate, and migration patterns of juvenile fish have not been documented precisely enough. Hopefully some of these uncertainties will be resolved through the salmon enhancement programs. Key words: salmon, population limitation, juvenile marine production, simulation model

scholarly journals Thermal constraints on stream consumer responses to a marine resource subsidy

2016 ◽  
Vol 73 (11) ◽  
pp. 1661-1671 ◽  
Author(s):  
Adrianne P. Smits ◽  
Daniel E. Schindler ◽  
Jonathan B. Armstrong ◽  
Michael T. Brett ◽  
Jackie L. Carter ◽  
...  
Keyword(s):  
Fatty Acid Composition ◽  
Fatty Acid ◽  
Body Size ◽  
Acid Composition ◽  
Body Condition ◽  
Sockeye Salmon ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Late Summer ◽  
Resource Subsidy

Spawning migrations of Pacific salmon (Oncorhynchus spp.) to coastal watersheds provide a rich resource subsidy to freshwater consumers. However, variation in thermal regimes and spawning activity across the landscape constrain the ability of poikilothermic consumers to assimilate eggs and carcasses. We investigated how sockeye salmon (Oncorhynchus nerka) spawning density and stream temperature affect the growth, body condition, and fatty acid composition of juvenile coho salmon (Oncorhynchus kisutch), a known egg predator, in seven tributaries of the Wood River in Southwest Alaska. We compared mean body size of juvenile coho salmon in late summer among 3–7 years per stream and found that the largest mean size occurred in warm streams in which sockeye salmon spawned, although overall subsidy magnitude (spawner density) had no effect on consumer body size. Individuals that consumed more salmon eggs (estimated from δ15N) were larger and had altered fatty acid composition but did not have higher relative body condition. These results indicate that effects of marine subsidies on freshwater consumers depend both on local habitat conditions and on individual variation in energy allocation.

Length of breeding life of coho salmon (Oncorhynchus kisutch)

1986 ◽  
Vol 64 (7) ◽  
pp. 1482-1486 ◽  
Author(s):  
Eric P. van Den Berghe ◽  
Mart R. Gross
Keyword(s):  
Body Size ◽  
Life Span ◽  
Water Level ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Important Variable ◽  
Negative Contribution ◽  
Breeding Grounds ◽  
Size Population ◽  
Males And Females

Since Pacific salmon (Oncorhynchus spp.) die on the breeding grounds after spawning, duration of individual life may affect survival of deposited eggs. In addition, breeding life of both sexes has implications for estimates of size of spawning populations. We therefore examined the contributions of body size, population density, water level, season, and year to length of breeding life in individual coho salmon (O. kisutch). Age 3 breeding males and females lived an average of 9 days (range, 2–30 days), and 2-year-old "jack" males averaged 8 days (range, 2–21 days). Sixteen percent of the variance among age 3 males and 44% of the variance among females could be explained by the variables examined. Density of adults made a significant negative contribution to life-span, while water level, season, and year were insignificant. Body size was the most important variable in explaining breeding life-span, being positively related and accounting for 10% and 36% of the variance in 3-year-old males and females, respectively. In contrast, none of these variables explained the observed variation in jack male breeding life. The differences between the sexes and between 2- and 3-year-old males are consistent with levels of competition on the breeding grounds. We show that the results on individual body size and breeding life span can be used to offset biases in population estimates.

Climate and conspecific density inform phenotypic forecasting of juvenile Pacific salmon body size

2021 ◽  
Author(s):  
Marta E. Ulaski ◽  
Heather Finkle ◽  
Anne H. Beaudreau ◽  
Peter A. H. Westley
Keyword(s):  
Body Size ◽  
Pacific Salmon ◽  
Conspecific Density ◽  
Juvenile Pacific Salmon

scholarly journals Direction and magnitude of natural selection on body size differ among age‐classes of seaward‐migrating Pacific salmon

2020 ◽  
Vol 13 (8) ◽  
pp. 2000-2013
Author(s):  
Marta E. Ulaski ◽  
Heather Finkle ◽  
Peter A. H. Westley
Keyword(s):  
Body Size ◽  
Natural Selection ◽  
Pacific Salmon ◽  
Age Classes
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