Recycling of Elements Transported Upstream by Runs of Pacific Salmon: I, δ15N and δ13C Evidence in Sashin Creek, Southeastern Alaska

1990 ◽  
Vol 47 (1) ◽  
pp. 136-144 ◽  
Author(s):  
Thomas C. Kline Jr. ◽  
John J. Goering ◽  
Ole A. Mathisen ◽  
Patrick H. Poe ◽  
Patrick L. Parker
Keyword(s):  
Rainbow Trout ◽  
Food Webs ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Organic C ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Control Section ◽  
The Difference ◽  
Δ15n And Δ13c

Values of δ15N and δ13C (the per mil deviation from the recognized isotope standard) from biota of a southeastern Alaska stream (Sashin Creek) that receives an annual run of 30 000 anadromous pink salmon (Oncorhynchus gorbuscha) were measured to determine sources of nitrogen (N) and carbon (C). Marine-derived nitrogen (MDN) is the predominant source of N for food webs found in the lower 1200 m of the stream which, due to a waterfall, is the only portion of the stream available to salmon returning to spawn. Comparable spawning section biota were enriched by about 5 per mil relative to the salmon-free control section, corresponding to the difference between 0 and 100% MDN in a mixing model. Food webs of resident rainbow trout (O. mykiss), at the outlet of one of the source lakes, Sashin Lake, have very low δ13C, suggesting the importance of a respired C pool in the lake. The source of C in the remainder of the stream is C fixation by autochthonous producers and marine organic C (within the salmon spawning section). Resident fishes in the salmon spawning section depend on MDN and some of the C delivered by the annual run of returning salmon.

Use of the stratified-Petersen estimator in fisheries management: estimating the number of pink salmon (Oncorhynchus gorbuscha) spawners in the Fraser River

1998 ◽  
Vol 55 (2) ◽  
pp. 281-296 ◽  
Author(s):  
Carl James Schwarz ◽  
Carolyn Gail Taylor
Keyword(s):  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Fraser River ◽  
Differential Migration ◽  
Mark Recapture ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
The Pacific ◽  
Recent Developments

The simple-Petersen estimator is a well-known mark-recapture method to estimate animal abundance. Two key assumptions are equal catchability in both samples and complete mixing of tagged and untagged animals. If these are violated, severe bias can occur. The stratified-Petersen estimator can be used to account for some of the heterogeneity in catchability or mixing. In this paper, we first review recent developments in the stratified-Petersen experiment for fisheries audiences and demonstrate some of the practical problems that can occur that have not been discussed in the theoretical literature. Second, we present a case study to estimate the gross escapement of Fraser River pink salmon (Oncorhynchus gorbuscha) in 1991. The motivation for this study is a discrepancy of over 5 million fish between the estimates as derived by the Pacific Salmon Commission (PSC) (7.5 million fish based on a hydroacoustic method) and the Department of Fisheries and Oceans (DFO), Canada (13.0 million fish based on a mark-recapture method). One hypothesis put forward was that the discrepancy may be due to the use of a pooled-Petersen estimator when there is differential migration over time. The stratified-Petersen model suggests that little of this discrepancy can be explained by differential migration.

Gravel Incubators: a Second Evaluation on Pink Salmon, Oncorhynchus gorbuscha, Including Adult Returns

1974 ◽  
Vol 31 (8) ◽  
pp. 1379-1385 ◽  
Author(s):  
Robert A. Bams
Keyword(s):  
Mass Production ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Survival Rates ◽  
Oncorhynchus Gorbuscha ◽  
Average Growth Rate ◽  
Average Growth ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Gain Ratio ◽  
Salmon Fry

A hatchery method designed for mass production of unfed Pacific salmon fry and utilizing a gravel medium during most of the incubation period is being evaluated on successive cycles of a stock of pink salmon, Oncorhynchus gorbuscha, of the Tsolum River, B.C. Possible treatment effects are studied at emergent fry and returning adult stages in artificially and naturally propagated populations. Average growth rate and, hence, efficiency of yolk conversion were unimpeded in the hatchery environment, but fry emerged 11 days prematurely. Survival from green egg to emergent fry averaged 74.9% in the hatchery and 20.6% in the creek, for a gain ratio at emergence of 3.63. Recovery of selectively marked populations of hatchery and creek fish demonstrated almost identical survival rates from fry to adult stages and a final gain ratio of 3.46. Adult lengths and weights, fecundity, and timing of migrations were unaffected generally by the hatchery treatment.

Effects of salmon on the diet and condition of stream-resident sculpins

2014 ◽  
Vol 71 (4) ◽  
pp. 521-532 ◽  
Author(s):  
Noel R. Swain ◽  
Morgan D. Hocking ◽  
Jennifer N. Harding ◽  
John D. Reynolds
Keyword(s):  
Chum Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Nitrogen Stable Isotope ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Carbon And Nitrogen ◽  
Stable Isotope Signatures ◽  
The Individual

Pacific salmon (Oncorhynchus spp.) can subsidize freshwater food webs with marine-derived nutrients from their eggs, juveniles, and carcasses. However, trophic interactions between spawning salmon and freshwater fish across natural gradients in salmon subsidies remain unclear. We tested how salmon affected the diets and condition of two dominant freshwater consumers — prickly and coastrange sculpins (Cottus asper and Cottus aleuticus, respectively) — across a wide gradient of pink salmon (Oncorhynchus gorbuscha) and chum salmon (Oncorhynchus keta) biomass from 33 streams in the Great Bear Rainforest of British Columbia, Canada. Sculpin diets shifted from invertebrates and juvenile salmonids to salmon eggs when salmon arrived in autumn, with salmon-derived nutrient contributions to diets and sculpin condition increasing with increasing biomass of spawning salmon among streams. Season, habitat, and individual sculpin body size and species also mediated the effects of salmon on sculpin diet as inferred from their carbon and nitrogen stable isotope signatures. This study shows the timing and pathways by which spawning salmon influence the diets and condition of freshwater consumers, and some of the individual and environmental factors that can regulate uptake of salmon nutrients in streams, thus informing ecosystem-based management.

The relative importance of prey density and social dominance in determining energy intake by bears feeding on Pacific salmon

2004 ◽  
Vol 82 (1) ◽  
pp. 75-85 ◽  
Author(s):  
S M Gende ◽  
T P Quinn
Keyword(s):  
Energy Intake ◽  
Social Dominance ◽  
Ursus Arctos ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Small Stream ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Coastal Streams

We quantified foraging behavior of brown bears (Ursus arctos) feeding on adult chum (Oncorhynchus keta) and pink salmon (Oncorhynchus gorbuscha) at three small coastal streams in southeastern Alaska from streamside tree stands. These observations revealed that social dominance was much more important in determining intake rates among bears than salmon densities. Each small stream supported one large, socially dominant bear that directly displaced other bears in aggressive encounters or was avoided in "passive deferrals". Although the number of fish killed per foraging bout was positively correlated with salmon density, energy intake was determined primarily by foraging effort, as dominant bears visited the stream more often and foraged for longer periods than subdominant bears. Capture efficiency (fish captured per minute searching) was highly variable and increased only marginally with salmon density and among social ranks. Subdominant bears were more vigilant, used a smaller fraction of each stream, and carried salmon much farther into the forest prior to consumption, presumably to minimize interactions with other bears. Social dominance may play an important role in regulating reproductive success when salmon densities are low and may have important implications for managers in bear-viewing areas.

Supplementary Checks on the Scales of Pink Salmon (Oncorhynchus gorbuscha) and Chum Salmon (O. keta)

1965 ◽  
Vol 22 (6) ◽  
pp. 1477-1489 ◽  
Author(s):  
H. T. Bilton ◽  
W. E. Ricker
Keyword(s):  
British Columbia ◽  
Chum Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Commercial Fisheries ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Clear Cut ◽  
Second Year Of Life ◽  
Second Year ◽  
Similar Incidence

Among 159 central British Columbia pink salmon that had been marked by removal of two fins as fry and had been recovered in commercial fisheries after one winter in the sea, the scales of about one-third showed a supplementary or "false" check near the centre of the scale, in addition to the single clear-cut annulus. This evidence from fish of known age confirms the prevailing opinion that such extra checks do not represent annuli, hence that the fish bearing them are in their second year of life rather than their third. Unmarked pink salmon from the same area, and some from southern British Columbia, had a generally similar incidence of supplementary checks. In both marked and unmarked fish the supplementary checks varied in distinctness from faint to quite clear. In a sample of scales of 14 double-fin marked chum salmon which were known to be in their 4th year, all fish had the expected 3 annuli, and 12 fish had a supplementary check inside the first annulus.

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