Transportation of Pacific salmon carcasses from streams to riparian forests by bears

2009 ◽  
Vol 87 (3) ◽  
pp. 195-203 ◽  
Author(s):  
Thomas P. Quinn ◽  
Stephanie M. Carlson ◽  
Scott M. Gende ◽  
Harry B. Rich, Jr.
Keyword(s):  
Spatial Distribution ◽  
Aquatic Ecosystems ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Riparian Forests ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Ecosystem Process ◽  
Direct Observations ◽  
Salmon Carcasses

Predation on Pacific salmon by bears (genus Ursus L., 1758) can be an important ecosystem process because the spatial distribution of carcasses largely determines whether marine-derived nutrients cycle through aquatic or terrestrial pathways. Direct observations on three streams in southeastern Alaska indicated that 49% of the pink ( Oncorhynchus gorbuscha (Walbaum, 1792)) and chum ( Oncorhynchus keta (Walbaum in Artedi, 1792)) salmon killed by bears were carried into the forest. The tendency of bears to transport carcasses was independent of the sex and species of salmon, but unspawned fish were more often transported than fish that had completed spawning. Data on tagged sockeye salmon ( Oncorhynchus nerka (Walbaum in Artedi, 1792)) in one southwestern Alaska stream indicated that 42.6% of the killed salmon were transported, and that higher percentages were transported in years when salmon densities were greater. At six other streams, on average, 68.1% of the sockeye salmon killed were apparently transported away from the stream into the forest. Combining the data from all sites, the proportion of carcasses transported increased with water depth at the site. These results emphasize the role that bears play in mediating the interactions between nutrients from salmon and the terrestrial and aquatic ecosystems, and the variation in carcass distribution among streams and among years.

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.

Consumption and distribution of salmon (Oncorhynchus spp.) nutrients and energy by terrestrial flies

2006 ◽  
Vol 63 (9) ◽  
pp. 2076-2086 ◽  
Author(s):  
Morgan D Hocking ◽  
Thomas E Reimchen
Keyword(s):  
Chum Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Isotope Analysis ◽  
Terrestrial Ecosystems ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
The North ◽  
Terrestrial Habitats ◽  
Salmon Carcasses

Anadromous Pacific salmon (Oncorhynchus spp.) subsidize terrestrial food webs with their nutrients and carcasses, a process driven largely by selective foraging by bears (Ursus spp.). We quantify wildlife transfer of salmon carcasses to riparian zones on two watersheds in coastal British Columbia and estimate total terrestrial fly production from remnant carcasses. Large-bodied chum salmon (Oncorhynchus keta) were transferred into the forest at a greater rate than were pink salmon (Oncorhynchus gorbuscha) (chum salmon mass = 6089–11 031 kg, 16%–48% of salmon run; pink salmon mass = 2266–2808 kg, 4%–6% of salmon run). Blow flies (genus Calliphora) and other Diptera dominated colonization (>90% of salmon carcasses). Between the two watersheds, 196 and 265 g of Calliphora larvae per metre of spawning length (4 and 7 million larvae for whole watersheds) were generated from salmon carcass transfer. Stable isotope analysis of δ15N and δ13C of spring-emerging adult Calliphora revealed that >80% of individuals had salmon-based signatures. Flies are a dominant consumer and vector of salmon nutrients in terrestrial habitats and supplement the diet of at least 16 vertebrate and 22 invertebrate species. Anticipated further declines of salmon in the North Pacific can be expected to further erode the complex associations coupling marine and terrestrial ecosystems.

scholarly journals On signals of phase transitions in salmon population dynamics

2014 ◽  
Vol 281 (1784) ◽  
pp. 20133221 ◽  
Author(s):  
Martin Krkošek ◽  
John M. Drake
Keyword(s):  
Phase Transitions ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Empirical Support ◽  
Growth Parameter ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Critical Transitions ◽  
Salmon Population

Critical slowing down (CSD) reflects the decline in resilience of equilibria near a bifurcation and may reveal early warning signals (EWS) of ecological phase transitions. We studied CSD in the recruitment dynamics of 120 stocks of three Pacific salmon ( Oncorhynchus spp.) species in relation to critical transitions in fishery models. Pink salmon ( Oncorhynchus gorbuscha ) exhibited increased variability and autocorrelation in populations that had a growth parameter, r , close to zero, consistent with EWS of extinction. However, models and data for sockeye salmon ( Oncorhynchus nerka ) indicate that portfolio effects from heterogeneity in age-at-maturity may obscure EWS. Chum salmon ( Oncorhynchus keta ) show intermediate results. The data do not reveal EWS of Ricker-type bifurcations that cause oscillations and chaos at high r . These results not only provide empirical support for CSD in some ecological systems, but also indicate that portfolio effects of age structure may conceal EWS of some critical transitions.

Historical trends in productivity of 120 Pacific pink, chum, and sockeye salmon stocks reconstructed by using a Kalman filter

2008 ◽  
Vol 65 (9) ◽  
pp. 1842-1866 ◽  
Author(s):  
Brigitte Dorner ◽  
Randall M. Peterman ◽  
Steven L. Haeseker
Keyword(s):  
Kalman Filter ◽  
Sockeye Salmon ◽  
Pacific Salmon ◽  
Stock Assessment ◽  
Temporal Trends ◽  
Survival Rates ◽  
Estimation Procedure ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Observation Error

Temporal trends in productivity of Pacific salmon ( Oncorhynchus spp.) stocks are important to detect in a timely and reliable manner to permit appropriate management responses. However, detecting such trends is difficult because observation error and natural variability in survival rates tend to obscure underlying trends. A Kalman filter estimation procedure has previously been shown to be effective in such situations. We used it on a Ricker spawner–recruit model to reconstruct indices of annual productivity (recruits per spawner (R/S) at low spawner abundance) based on historical data for 120 stocks of pink ( Oncorhynchus gorbuscha ), chum ( Oncorhynchus keta ), and sockeye ( Oncorhynchus nerka ) salmon. These stocks were from Washington, British Columbia, and Alaska. The resulting estimated temporal trends in productivity show large changes (on average 60%–70% differences in R/S and average ratios of highest to lowest R/S between 5.4 and 7.9 for the three species). Such changes suggest that salmon stock assessment methods should take into account possible nonstationarity. This step will help provide scientific advice to help managers to meet conservation and management objectives. The Kalman filter results also identified some stocks that did not share temporal trends with other stocks; these exceptions may require special monitoring and management efforts.

scholarly journals Sea to sky: impacts of residual salmon-derived nutrients on estuarine breeding bird communities

2011 ◽  
Vol 278 (1721) ◽  
pp. 3081-3088 ◽  
Author(s):  
Rachel D. Field ◽  
John D. Reynolds
Keyword(s):  
Pacific Salmon ◽  
Bird Communities ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Breeding Bird ◽  
The North ◽  
Bird Density ◽  
Post Spawning ◽  
The North Pacific ◽  
Forest Habitats

Pacific salmon ( Oncorhynchus spp.) returning to streams around the North Pacific Rim provide a nutrient subsidy to these ecosystems. While many species of animals feed directly on salmon carcasses each autumn, salmon-derived nutrients can also be stored in coastal habitats throughout the year. The effects of this storage legacy on vertebrates in other seasons are not well understood, especially in estuaries, which can receive a large portion of post-spawning salmon nutrients. We examine the effects of residual salmon-derived nutrients, forest habitats and landscape features on summer breeding birds in estuary forests. We compared models containing environmental variables and combined chum ( Oncorhynchus keta ) and pink ( Oncorhynchus gorbuscha ) salmon biomass to test predictions concerning bird density and diversity. We discovered that total bird, insectivore, golden-crowned kinglet and Pacific wren densities and Shannon's diversity in the summer were strongly predicted by salmon biomass in the autumn. For most metrics, this relationship approaches an asymptote beyond 40 000 kg of salmon biomass. Foliage height diversity, watershed catchment area and estuary area were also important predictors of avian communities. Our study suggests that the legacy of salmon nutrients influences breeding bird density and diversity in estuaries that vary across a wide gradient of spawning salmon biomass.

Oceanographic influences on patterns in North Pacific salmon abundance

2014 ◽  
Vol 71 (2) ◽  
pp. 226-235 ◽  
Author(s):  
Megan M. Stachura ◽  
Nathan J. Mantua ◽  
Mark D. Scheuerell
Keyword(s):  
North American ◽  
North Pacific ◽  
Sockeye Salmon ◽  
Large Scale ◽  
Gulf Of Alaska ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
North American Population ◽  
Regional Patterns ◽  
Abundance Pattern

We identified three dominant patterns of temporal variation (1951–2002) in the abundance of 34 stock groups of wild North American and Asian pink salmon (Oncorhynchus gorbuscha), chum salmon (Oncorhynchus keta), and sockeye salmon (Oncorhynchus nerka) that were related to patterns of oceanographic variability. We identified these patterns using three different ordination methods and found consistent patterns across these methods. Alaskan salmon dominated the most prominent pattern, which exhibited a positive abundance shift in the mid-1970s. In general, warm (cold) periods in the Gulf of Alaska and eastern Bering Sea corresponded with high (low) abundance years for these stock groups. The second abundance pattern captured differences among Asian, northern North American, and southern North American population groups and was associated with an intense, large-scale Aleutian Low. To our knowledge, this is the first analysis that identifies regional patterns of covariation in salmon abundance around the entire North Pacific Rim, and it highlights the existence of basin-wide covariations in wild salmon abundance that are associated with spatially coherent and regionally distinct patterns in North Pacific climate.

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.

scholarly journals Response of the Sea Louse Lepeophtheirus salmonis Infestation Levels on Juvenile Wild Pink, Oncorhynchus gorbuscha, and Chum, O. keta, Salmon to Arrival of Parasitized Wild Adult Pink Salmon

2006 ◽  
Vol 120 (2) ◽  
pp. 199
Author(s):  
Alexandra Morton ◽  
Rob Williams
Keyword(s):  
Chum Salmon ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Primary Source ◽  
Sea Lice ◽  
Oncorhynchus Gorbuscha ◽  
Oncorhynchus Keta ◽  
Lepeophtheirus Salmonis ◽  
Louse Infestation ◽  
Age Cohorts

Recent recurring infestations of Sea Lice, Lepeophtheirus salmonis, on juvenile Pacific salmon (Oncorhynchus spp.) and subsequent annual declines of these stocks have made it imperative to identify the source of Sea Lice. While several studies now identify farm salmon populations as sources of Sea Louse larvae, it is unclear to what extent wild salmonid hosts also contribute Sea Lice. We measured Sea Louse numbers on adult Pink Salmon (Oncorhynchus gorbuscha) migrating inshore. We also measured Sea Louse numbers on wild juvenile Pink and Chum salmon (Oncorhynchus keta) migrating to sea before the adults returned, and as the two age cohorts mingled. Adult Pink Salmon carried an average of 9.89 (SE 0.90) gravid lice per fish, and thus were capable of infecting the adjacent juveniles. Salinity and temperature remained favourable to Sea Louse reproduction throughout the study. However, all accepted measures of Sea Louse infestation failed to show significant increase on the juvenile salmon, either in overall abundance of Sea Lice or of the initial infective-stage juvenile lice, while the adult wild salmon were present in the study area. This study suggests that even during periods of peak interaction, wild adult salmon are not the primary source of the recent and unprecedented infestations of Sea Lice on juvenile Pacific Pink and Chum salmon in the inshore waters of British Columbia.

Advances in Fish Tagging and Marking Technology

2012 ◽  
Keyword(s):  
Sockeye Salmon ◽  
Oncorhynchus Tshawytscha ◽  
Pacific Salmon ◽  
Area Under The Curve ◽  
Dorsal Surface ◽  
Field Trials ◽  
Oncorhynchus Keta ◽  
Survey Costs ◽  
Tank Test ◽  
Auc Estimation

<i>Abstract</i>.—A micro-controlled fish tag which records post-tagging lifespan was developed, tested as a prototype, and then evaluated in field applications for measuring survey life. The method of constructing the Tilt-Tag and the results of tank test trials on Chinook salmon <i>Oncorhynchus tshawytscha</i>, preliminary field trials on chum salmon <i>Oncorhynchus keta </i>are reviewed, and full-scale field applications on sockeye salmon <i>Oncorhynchus nerka </i>are presented. Survey life (SL) is an essential component for area-under-the-curve (AUC) estimation of Pacific salmon <i>Oncorhynchus </i>spp. spawning escapements. However, direct estimates of SL are often unavailable because the estimates mostly require extensive and costly tag-recapture programs. In this study, the Tilt-Tag was used to estimate SL by measuring the elapsed time from tagging until the fish came to rest permanently on its lateral or dorsal surface. Tilt-Tag derived estimates of SL, combined with specification of survey rules that were based on historical run-timing and stream temperature, reduced survey costs by approximately 50% when compared to conventional tag-recapture methods. Abridged details on how to construct the Tilt-Tag are provided so that researchers will be able to make their own tags.

Effect of incubation temperature on the development of five species of Pacific salmon (Oncorhynchus) embryos and alevins

1988 ◽  
Vol 66 (1) ◽  
pp. 266-273 ◽  
Author(s):  
C. B. Murray ◽  
J. D. McPhail
Keyword(s):  
Chinook Salmon ◽  
Sockeye Salmon ◽  
Coho Salmon ◽  
Incubation Temperature ◽  
Pacific Salmon ◽  
Pink Salmon ◽  
Oncorhynchus Gorbuscha ◽  
Embryo Survival ◽  
Salmon Fry ◽  
Incubation Temperatures

Embryo and alevin survival, time to hatching and emergence, and alevin and fry size of five species of Pacific salmon (Oncorhynchus) were observed at five incubation temperatures (2, 5, 8, 11, and 14 °C). No pink (Oncorhynchus gorbuscha) or chum (O. keta) salmon embryos survived to hatching at 2 °C. Coho (O. kisutch) and sockeye (O. nerka) salmon had higher embryo survival at 2 °C than chinook (O. tschawytscha) salmon. At 14 °C, chum, pink, and chinook salmon had higher embryo survival than coho or sockeye salmon. In all species, peaks of embryo mortality occurred at specific developmental stages (completion of epiboly, eye pigmentation, and hatching). Alevin survival to emergence was high for all species, except for coho and pink salmon at 14 °C. Hatching and emergence time varied inversely with incubation temperature, but coho salmon hatched and emerged sooner at all temperatures than the other species. Coho and sockeye salmon alevins were larger at 2 °C, pink, chum, and chinook salmon alevins were larger at 5 and 8 °C. Coho salmon fry were larger at 2 °C, chinook and chum salmon fry were larger at 5 °C, and sockeye and pink salmon fry were larger at 8 °C. High incubation temperatures reduced fry size in all species. Each species of Pacific salmon appears to be adapted to different spawning times and temperatures, and thus indirectly to specific incubation temperatures, to ensure maximum survival and size and to maintain emergence at the most favorable time each year.

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