Influence of salmon spawner densities on stream productivity in Southeast Alaska

1999 ◽  
Vol 56 (9) ◽  
pp. 1600-1611 ◽  
Author(s):  
Mark S Wipfli ◽  
John P Hudson ◽  
Dominic T Chaloner ◽  
John P Caouette
Keyword(s):  
Chlorophyll A ◽  
Pink Salmon ◽  
Dry Mass ◽  
Trophic Levels ◽  
Oncorhynchus Gorbuscha ◽  
Southeast Alaska ◽  
Natural Stream ◽  
Forest Stream ◽  
Natural Streams ◽  
Freshwater Salmon

We conducted this study to determine the relationship between salmon spawner abundance and stream biofilm and benthic macroinvertebrate abundance in Southeast Alaska. Experiments took place in outdoor artificial and natural streams. Six pink salmon (Oncorhynchus gorbuscha) carcass treatments (0.00, 1.45, 2.90, 4.35, 5.80, and 7.25 kg wet mass) placed in artificial channels were subsampled repeatedly for biofilm ash-free dry mass (AFDM), chlorophyll a, and macroinvertebrates. In a small (nonanadromous) forest stream, we sampled benthos throughout a 66-m reach 17 days after distributing 60 carcasses along the lower half of that reach. All response variables significantly increased in response to carcass additions in both artificial and natural streams. Chlorophyll a continued to increase across all loading rates, while AFDM and total macroinvertebrate densities showed no further response to loading beyond the first treatment (1.45 kg) in artificial streams. In the natural stream, AFDM and chironomid densities continued increasing across loading levels. These results indicated that increased spawner densities increased lower trophic level abundance until a trophic capacity was reached. Salmon escapement goals should consider food web effects, especially on trophic levels that support juvenile salmonids, that ultimately affect freshwater salmon production.

Possible Effects of the Sitka Eddy on Sockeye (Oncorhynchus nerka) and Pink Salmon (Oncorhynchus gorbuscha) Migration off Southeast Alaska

1986 ◽  
Vol 43 (2) ◽  
pp. 498-504 ◽  
Author(s):  
Kevin Hamilton ◽  
Lawrence A. Mysak
Keyword(s):  
Oncorhynchus Nerka ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Surface Currents ◽  
Oceanic Circulation ◽  
Migration Routes ◽  
Southeast Alaska ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Northeast Pacific ◽  
Northeast Pacific Ocean

The interannual variability of sockeye (Oncorhynchus nerka) and pink salmon (Oncorhynchus gorbuscha) catches during 1952–62 from southeast Alaska and northern British Columbia is examined in relation to the appearance and disappearance of the Sitka eddy in the offshore oceanic circulation. In years when this large (~300 km in diameter) and intense (surface currents ~0.5 m/s) vortex is present, the spawning migration routes of salmon returning to the Nass and Skeena rivers tend to be deflected southward. An analysis of salmon tagging data collected during 1957 (when the eddy was absent) and 1958 (when the eddy was present) supports this conclusion. The southward deflection during 1958 is a particularly interesting result in light of many other observations which show that several fish species were displaced northward during the 1958 warming of the northeast Pacific Ocean.

Variations in Annual Average Weights of British Columbia Pink Salmon, 1944–1958

1959 ◽  
Vol 16 (3) ◽  
pp. 329-337 ◽  
Author(s):  
Harold Godfrey
Keyword(s):  
British Columbia ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Steady Increase ◽  
Average Weight ◽  
Weight Changes ◽  
Southeast Alaska ◽  
Annual Changes ◽  
Average Size ◽  
Weight Data

Average weight data of British Columbia pink salmon, Oncorhynchus gorbuscha, since 1944 were made available by the Fisheries Association of British Columbia, and were used to compare annual changes in size among stocks throughout the Province. Adult pinks of the odd-year cycle were almost invariably larger than those of the even-year cycle. In British Columbia this cycle has also been consistently the more abundant, and in southeast Alaska these fish have been either about equally as numerous as the even-year pinks, or, upon occasion, much more numerous. The pink salmon of each of the major fishing areas in the Province show similar annual changes in average weight. From an extremely small average size in 1946 there was a trend of steady increase, among all stocks and involving both cycles, over the next 8 years; this was followed by a decline in 1955 and 1956, then a further increase in 1957 and 1958. A comparison between southeastern Alaska pinks and pinks of northern British Columbia showed that they had experienced similar year-to-year weight changes during the earlier period of 1930–1939.

Genetic Aanalysis of Size in an Anadromous Population of Pink Salmon

1994 ◽  
Vol 51 (S1) ◽  
pp. 9-15 ◽  
Author(s):  
William W. Smoker ◽  
Anthony J. Gharrett ◽  
Michael S. Stekoll ◽  
John E. Joyce
Keyword(s):  
Variance Components ◽  
Genetic Basis ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Southeast Alaska ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Factors Affecting ◽  
Phenotypic Correlations ◽  
Sib Families ◽  
Mature Fish

Variation of size, particularly among males, has a significant genetic basis in pink salmon (Oncorhynchus gorbuscha) in Auke Creek, southeast Alaska. Heritability (h2), based on variance components of 118 full sib − 59 paternal half sib families of mature fish tagged as fry with coded micro wires, are higher in males (h2 length: 0.8 ± 0.3 (mean ± SE); h2 weight: 0.6 ± 0.2, based on sire effect) than in females (h2 length: 0.3 ± 0.2; h2 weight: 0.4 ± 0.2). Realized heritability probably would be smaller because of environment variability between brood years in factors affecting size and growth. Estimates based on regression of offspring means on fathers' values are smaller (h2 length: 0.4 ± 0.1 in males; 0.2 ± 0.1 in females; h2 weight: 0.0 in males and 0.1 ± 0.1 in females). Estimates of genetic, environmental, and phenotypic correlations of length and weight are all >0.7 (SEs <0.1). Estimates of genetic correlation between length and day of migration from the sea are near 0.4 ± 0.2; estimates of environmental and phenotypic correlations between these traits are smaller (<0.2, SEs <0.1).

scholarly journals Gulls, Larus spp., Foraging at Pink Salmon, Oncorhynchus gorbuscha, Spawning Runs

2004 ◽  
Vol 118 (3) ◽  
pp. 442
Author(s):  
Mary F. Willson
Keyword(s):  
Body Size ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Dominance Status ◽  
Southeast Alaska ◽  
Physical Strength ◽  
Salmon Eggs ◽  
Foraging Experience ◽  
Salmon Carcasses

Small and immature gulls foraged more often on drifting salmon eggs than did large and mature gulls, and large and mature gulls foraged more often on salmon carcasses, at streams in Southeast Alaska. These differences may be related to body size via physical strength and dominance status, as well as foraging experience.

A hierarchical Bayesian model for estimating historical salmon escapement and escapement timing

2001 ◽  
Vol 58 (8) ◽  
pp. 1648-1662 ◽  
Author(s):  
Zhenming Su ◽  
Milo D Adkison ◽  
Benjamin W Van Alen
Keyword(s):  
Count Data ◽  
Bayesian Model ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Hierarchical Bayesian ◽  
Hierarchical Bayesian Model ◽  
Southeast Alaska ◽  
Pink Salmon Oncorhynchus Gorbuscha ◽  
Statistical Framework ◽  
Borrowing Strength

In this paper, we present an improved methodology for estimating salmon escapements from stream count data. The new method uses a hierarchical Bayesian model that improves estimates in years when data are sparse by "borrowing strength" from counts in other years. We present a model of escapement and of count data, a hierarchical Bayesian statistical framework, a Gibbs sampling approach for evaluation of the posterior distributions of the quantities of interest, and criteria for determining when the model and inference are adequate. We then apply the hierarchical Bayesian model to estimating historical escapement and escapement timing for pink salmon (Oncorhynchus gorbuscha) returns to Kadashan Creek in Southeast Alaska.

Salmon carcasses as a marine-derived resource for benthic macroinvertebrates in a developing postglacial stream, Alaska

2008 ◽  
Vol 65 (7) ◽  
pp. 1342-1351 ◽  
Author(s):  
Kieran A. Monaghan ◽  
Alexander M. Milner
Keyword(s):  
Community Structure ◽  
Benthic Macroinvertebrates ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Separate Experiment ◽  
Macroinvertebrate Communities ◽  
Southeast Alaska ◽  
Stream Macroinvertebrate ◽  
Experimental Approaches ◽  
And Control

Streams formed in Glacier Bay, southeast Alaska, following glacial recession rapidly support populations of spawning salmon. Using both observational and experimental approaches, we examined the importance of pink salmon ( Oncorhynchus gorbuscha ) carcasses for benthic macroinvertebrate communities, approximately 10 years after salmon first colonized Wolf Point Creek, a first-order, lake-fed stream. Macroinvertebrate abundance on carcasses naturally accumulating in the stream channel was low, dominated by chironomids ( Eukiefferiella spp.). Macroinvertebrate drift was significantly lower from artificial experimental channels containing salmon flesh (P < 0.001) compared with channels without. However, the density and community structure of macroinvertebrates colonizing rock baskets in channels was not significantly different between treatments. In a separate experiment, colonization of substrate trays with salmon and control (inert) fillets were associated with differences in community structure; simuliids dominated control fillets, and chironomids dominated fish fillets, while underlying stone substrate was colonized by a more diverse community including Ephemeroptera, Plecoptera, and Trichoptera taxa (EPT). Excluding simuliids, abundance was significantly higher on fish compared with control fillets (P < 0.001). These data suggest that scales and mucus prevent the direct consumption of flesh from whole carcasses, highlighting the role predators–scavengers in facilitating flesh consumption by benthic macroinvertebrates.

Influence of salmon carcasses on stream productivity: response of biofilm and benthic macroinvertebrates in southeastern Alaska, U.S.A.

1998 ◽  
Vol 55 (6) ◽  
pp. 1503-1511 ◽  
Author(s):  
Mark S Wipfli ◽  
John Hudson ◽  
John Caouette
Keyword(s):  
Block Design ◽  
Dry Mass ◽  
Feedback Mechanism ◽  
Artificial Streams ◽  
Natural Stream ◽  
Incomplete Block Design ◽  
Natural Streams ◽  
Positive Feedback Mechanism ◽  
Salmon Carcass ◽  
Salmon Carcasses

This study was conducted to determine if salmon carcasses (from spawning adults) increased stream biofilm ash-free dry mass (AFDM) and benthic macroinvertebrate abundance in southeastern Alaska, U.S.A. Thirty-six once-through artificial streams were situated along, and received water and drifting invertebrates from, a natural stream. Two treatments (salmon carcass, control) were sampled six times during a 3-month period in a randomized incomplete block design with a 2 x 6 factorial treatment structure. Additionally, two natural stream sites were sampled once for biofilm and macroinvertebrates, one site receiving 75 000 adult salmon migrants during 1996 and the other upstream of spawning salmon. While biofilm AFDM was 15 times higher in carcass-enriched reaches of Margaret Creek, there were no detectable treatment differences in the artificial streams. Total macroinvertebrate densities were up to eight and 25 times higher in carcass-enriched areas of artificial and natural streams, respectively; Chironomidae midges, Baetis and Cinygmula mayflies, and Zapada stoneflies were the most abundant taxa. The increased biofilm in Margaret Creek and macroinvertebrate abundance in both systems suggest that salmon carcasses elevated freshwater productivity. This marine-based positive feedback mechanism may be crucial for sustaining aquatic-riparian ecosystem productivity and long-term salmonid population levels.

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