scholarly journals Implications of a warming eastern Bering Sea for Bristol Bay sockeye salmon

2011 ◽  
Vol 68 (6) ◽  
pp. 1138-1146 ◽  
Author(s):  
Edward V. Farley ◽  
Alexander Starovoytov ◽  
Svetlana Naydenko ◽  
Ron Heintz ◽  
Marc Trudel ◽  
...  
Keyword(s):  
Bering Sea ◽  
Sockeye Salmon ◽  
Large Scale ◽  
Pacific Salmon ◽  
Bristol Bay ◽  
Eastern Bering Sea ◽  
New Information ◽  
Energy Stores ◽  
Overwinter Mortality ◽  
Dependent Processes

Abstract Farley, E. V., Starovoytov, A., Naydenko, S., Heintz, R., Trudel, M., Guthrie, C., Eisner, L., Guyon, J. R. 2011. Implications of a warming eastern Bering Sea for Bristol Bay sockeye salmon. – ICES Journal of Marine Science, 68: 1138–1146. Overwinter survival of Pacific salmon (Oncorhynchus sp.) is believed to be a function of size and energetic status they gain during their first summer at sea. We test this notion for Bristol Bay sockeye salmon (O. nerka), utilizing data from large-scale fisheries and oceanographic surveys conducted during mid-August to September 2002–2008 and from February to March 2009. The new data presented in this paper demonstrate size-selective mortality for Bristol Bay sockeye salmon between autumn and their first winter at sea. Differences in the seasonal energetic signatures for lipid and protein suggest that these fish are not starving, but instead the larger fish caught during winter apparently are utilizing energy stores to minimize predation. Energetic status of juvenile sockeye salmon was also strongly related to marine survival indices and years with lower energetic status apparently are a function of density-dependent processes associated with high abundance of juvenile sockeye salmon. Based on new information regarding eastern Bering Sea ecosystem productivity under a climate-warming scenario, we hypothesize that sustained increases in spring and summer sea temperatures may negatively affect energetic status of juvenile sockeye salmon, potentially resulting in increased overwinter mortality.

scholarly journals Climate and competition influence sockeye salmon population dynamics across the Northeast Pacific Ocean

2020 ◽  
Vol 77 (6) ◽  
pp. 943-949 ◽  
Author(s):  
Brendan Connors ◽  
Michael J. Malick ◽  
Gregory T. Ruggerone ◽  
Pete Rand ◽  
Milo Adkison ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Large Scale ◽  
Pacific Salmon ◽  
Spatial Scales ◽  
Interspecific Interactions ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Negative Effects ◽  
Positive Effects ◽  
The North

Pacific salmon productivity is influenced by ocean conditions and interspecific interactions, yet their combined effects are poorly understood. Using data from 47 North American sockeye salmon (Oncorhynchus nerka) populations, we present evidence that the magnitude and direction of climate and competition effects vary over large spatial scales. In the south, a warm ocean and abundant salmon competitors combined to strongly reduce sockeye productivity, whereas in the north, a warm ocean substantially increased productivity and offset the negative effects of competition at sea. From 2005 to 2015, the approximately 82 million adult pink salmon (Oncorhynchus gorbuscha) produced annually from hatcheries were estimated to have reduced the productivity of southern sockeye salmon by ∼15%, on average. In contrast, for sockeye at the northwestern end of their range, the same level of hatchery production was predicted to have reduced the positive effects of a warming ocean by ∼50% (from a ∼10% to a ∼5% increase in productivity, on average). These findings reveal spatially dependent effects of climate and competition on sockeye productivity and highlight the need for international discussions about large-scale hatchery production.

Dendrogaster (Crustacea: Ascothoracida) parasitic in Alaskan and eastern Canadian Leptasterias (Asteroidea)

1986 ◽  
Vol 64 (6) ◽  
pp. 1249-1253 ◽  
Author(s):  
Mark J. Grygier
Keyword(s):  
Bering Sea ◽  
Western Hemisphere ◽  
Sea Star ◽  
Bristol Bay ◽  
Eastern Bering Sea ◽  
Middle Piece ◽  
Davis Strait ◽  
Leptasterias Polaris

The ascothoracid parasite Dendrogaster is reported from four boreal localities in the Western Hemisphere. Dendrogaster elegans Wagin infests the sea star Leptasterias polaris in Bristol Bay, Alaska, and in the Gulf of St. Lawrence; the eastern specimens have a shorter brood sac middle piece. A lectotype is selected and described for D. arctica Korschelt from L. groenlandica in the eastern Bering Sea; Siberian specimens previously assigned to this species differ from the type in many details. Immature specimens of an unidentified Dendrogaster species have been found in L. floccosa from the Davis Strait.

A hierarchical model for salmon run reconstruction and application to the Bristol Bay sockeye salmon (Oncorhynchus nerka) fishery

2006 ◽  
Vol 63 (7) ◽  
pp. 1564-1577 ◽  
Author(s):  
Lucy Flynn ◽  
André E Punt ◽  
Ray Hilborn
Keyword(s):  
Hierarchical Structure ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Nerka ◽  
Model Development ◽  
Bristol Bay ◽  
Process Error ◽  
The Hierarchical Structure ◽  
River Test ◽  
Run Timing

The goal of spreading the annual catch of a Pacific salmon (Oncorhynchus spp.) run proportionally across all segments of the migration is rendered difficult or impossible because of the interannual variability in both run size and run timing. This problem is particularly acute in the case of the fishery for sockeye salmon (Oncorhynchus nerka) in Bristol Bay, Alaska, for which traditional run reconstruction models are not applicable because of the extreme temporal compression of the run. We develop a run reconstruction model appropriate for sockeye salmon in Bristol Bay by accounting for the hierarchical structure of the problem and by including process error. Our results indicate that the hierarchical structure is, in fact, not necessary, whereas the process error parameters are needed to fit the data. We suggest further model development without the hierarchical structure, including incorporating in-river test fishing data. The results of our method can be used to address questions regarding environmental or intrinsic drivers of run timing and the possibility of artificial selection on run timing.

Homing behavior and vertical movements of four species of Pacific salmon (Oncorhynchus spp.) in the central Bering Sea

1995 ◽  
Vol 52 (3) ◽  
pp. 532-540 ◽  
Author(s):  
Miki Ogura ◽  
Yukimasa Ishida
Keyword(s):  
Chinook Salmon ◽  
Bering Sea ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Depth Sensing ◽  
Compass Orientation ◽  
Homing Behavior ◽  
Vertical Movements ◽  
Strong Surface

Four sockeye salmon (Oncorhynchus nerka), two chum salmon (O. keta), three pink salmon (O. gorbuscha), and four Chinook salmon (O. tshawytscha) with depth-sensing ultrasonic transmitters were tracked in the central Bering Sea to examine migration in the open sea. Ground speeds of maturing sockeye, chum, and pink salmon were at 0.54–0.66 m/s (0.88–1.17 fork lengths/s). Chinook salmon, probably immature fish, moved more slowly (0.34 m/s). Maturing individuals moved in particular directions and maintained their ground speeds and directions during day and night. The results also suggested that salmon had a compass orientation ability functioning without celestial information. Sockeye, chum, and pink salmon showed strong surface preferences but chinook salmon swam deeper (30–35 m) than did the other species.

Recycling of Elements Transported Upstream by Runs of Pacific Salmon: II. δ15N and δ13C Evidence in the Kvichak River Watershed, Bristol Bay, Southwestern Alaska

1993 ◽  
Vol 50 (11) ◽  
pp. 2350-2365 ◽  
Author(s):  
Thomas C. Kline Jr. ◽  
John J. Goering ◽  
Ole A. Mathisen ◽  
Patrick H. Poe ◽  
Patrick L. Parker ◽  
...  
Keyword(s):  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Coast Range ◽  
Bristol Bay ◽  
River Watershed ◽  
Dual Isotope ◽  
Salmon Juvenile ◽  
Dietary Component ◽  
Δ15n And Δ13c ◽  
Southwestern Alaska

Biota δ15N and δ13C values (deviations from recognized isotope standards) from lliamna Lake (a major anadromous sockeye salmon (Oncorhynchus nerka) nursery lake supporting peak-year runs > 10 million) and several other anadromous-salmon-free lakes in the Kvichak River watershed, Bristol Bay, southwestern Alaska, were compared to determine the significance of marine-derived nitrogen (MDN) delivered by returning adult salmon. Biota in lliamna Lake had higher δ15N compared with control lakes, verifying a mixing model correlating δ15N with MDN. Periphyton δ15N values reflected localized input from populations of spawning salmon. Juvenile sockeye MDN varied in response to escapement size, suggesting the importance of large escapements (> 10 million) for maintaining a predominantly MDN lacustrine N pool. Other resident fishes showed shifts in δ15N between years of high and low escapement. The dual-isotope approach, using δ15N and δ13C together, suggested that fish production is primarily dependent on limnetic primary and secondary production. The dual-isotope approach indicated that the coast range sculpin (Cottus aleuticus) was the only fish with an appreciable dietary component consisting of salmon eggs or emergent fry.

scholarly journals Collective navigation can facilitate passage through human-made barriers by homeward migrating Pacific salmon

2020 ◽  
Vol 287 (1937) ◽  
pp. 20202137
Author(s):  
Connie Okasaki ◽  
Matthew L. Keefer ◽  
Peter A. H. Westley ◽  
Andrew M. Berdahl
Keyword(s):  
Sockeye Salmon ◽  
Large Scale ◽  
Potential Role ◽  
Pacific Salmon ◽  
Passage Time ◽  
Natural World ◽  
Density Effects ◽  
Mass Migration ◽  
Collective Navigation

The mass migration of animals is one of the great wonders of the natural world. Although there are multiple benefits for individuals migrating in groups, an increasingly recognized benefit is collective navigation, whereby social interactions improve animals’ ability to find their way. Despite substantial evidence from theory and laboratory-based experiments, empirical evidence of collective navigation in nature remains sparse. Here we used a unique large-scale radiotelemetry dataset to analyse the movements of adult Pacific salmon ( Oncorhynchus sp.) in the Columbia River Basin, USA. These salmon face substantial migratory challenges approaching, entering and transiting fishways at multiple large-scale hydroelectric mainstem dams. We assess the potential role of collective navigation in overcoming these challenges and show that Chinook salmon ( O. tshawytscha ), but not sockeye salmon ( O. nerka ) locate fishways faster and pass in fewer attempts at higher densities, consistent with collective navigation. The magnitude of the density effects were comparable to major established drivers such as water temperature, and model simulations predicted that major fluctuations in population density can have substantial impacts on key quantities including mean passage time and fraction of fish with very long passage times. The magnitude of these effects indicates the importance of incorporating conspecific density and social dynamics into models of the migration process. Density effects on both ability to locate fishways and number of passage attempts have the potential to enrich our understanding of migratory energetics and success of migrating anadromous salmonids. More broadly, our work reveals a potential role of collective navigation, in at least one species, to mitigate the effects of anthropogenic barriers to animals on the move.

scholarly journals Silent ships do not always encounter more fish (revisited): comparison of acoustic backscatter from walleye pollock recorded by a noise-reduced and a conventional research vessel in the eastern Bering Sea

2011 ◽  
Vol 68 (10) ◽  
pp. 2229-2239 ◽  
Author(s):  
Alex De Robertis ◽  
Christopher D. Wilson
Keyword(s):  
Bering Sea ◽  
Large Scale ◽  
Walleye Pollock ◽  
Target Strength ◽  
Acoustic Backscatter ◽  
Research Vessel ◽  
Night Time ◽  
Strong Reaction ◽  
Eastern Bering Sea ◽  
Bering Sea Shelf

Abstract De Robertis, A., and Wilson, C. D. 2011. Silent ships do not always encounter more fish (revisited): comparison of acoustic backscatter from walleye pollock recorded by a noise-reduced and a conventional research vessel in the eastern Bering Sea. – ICES Journal of Marine Science, 68: 2229–2239. Vessel-induced avoidance behaviour is potentially a major source of error in surveys of fish populations. Noise-reduced research vessels have been constructed in an effort to minimize fish reactions to auditory stimuli produced by survey vessels. Here, measurements of acoustic backscatter from walleye pollock (Theragra chalcogramma) made on the eastern Bering Sea Shelf from the conventional NOAA ship “Miller Freeman” (MF) are compared with similar measurements made on the noise-reduced NOAA ship “Oscar Dyson” (OD). As in a previous study, acoustic abundance measurements from these vessels were equivalent during daylight, when large-scale acoustic surveying is conducted. However, significant differences were observed at night: on average, 44% more pollock backscatter was observed from OD than MF. Observations with a free-drifting echosounder buoy suggest that the night-time discrepancy is attributable to a stronger behavioural response to the passage of the louder MF, and a resulting decrease in pollock target strength. Pollock did not exhibit a strong reaction to the passage of OD. These observations are consistent with previous comparisons of these vessels, which show that with vessel differences, the noise-reduced OD detects more pollock.

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