The Northern Oscillation Index (NOI): a new climate index for the northeast Pacific

Schwing, Franklin B.; Murphree, Tom; Green, P.M

doi:10.1016/s0079-6611(02)00027-7

Cited by 180 publications

(140 citation statements)

References 45 publications

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“…washington.edu/pdo/PDO.latest; Mantua and Hare 2002), the Aleutian Low Pressure Index (ALPI; Trenberth and Hurrell 1995), and the Northern Oscillation Index (NOI; Schwing et al 2002).…”

Section: Methodsmentioning

confidence: 99%

Understanding Smolt Survival Trends in Sockeye Salmon

Irvine

Akenhead

2013

Mar Coast Fish

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Many populations of Sockeye Salmon Oncorhynchus nerka in the eastern North Pacific Ocean experienced significant productivity declines that began about 1990, but there is no consensus on the mechanisms responsible. To better understand Sockeye Salmon survival trends, we examined the 50-year time series for two age-classes of Sockeye Salmon smolts from Chilko Lake in central British Columbia. Arranging survival time series for both age-classes by ocean entry year and combining them, weighted by a proxy model of sampling variance, reduced the sampling variance in the original age-1 smolt survivals sufficiently to indicate a linear trend of increasing survival from 1960 to 1990 that suddenly changed at or near 1991 to a lower and declining trend from 1992 to 2008. Neither density nor mean length influenced smolt survival. Returns in a given year were not good predictors of siblings returning in subsequent years. Time spent at sea increased linearly beginning around 1970. Although smolt survivals differed between ecosystem regimes, there was only the one clear pattern break about 1991. To improve our understanding of mechanisms, survival trends were compared with environmental indices that included catches and hatchery releases of potentially competing salmon from around the North Pacific Ocean. Smolt survivals were more similar to abundance indices of Sockeye Salmon, Chum Salmon O. keta, and Pink Salmon O. gorbuscha than to indices of global, regional, or local ocean climate. Our results are consistent with the hypothesis that salmon productivity in the North Pacific declined soon after 1990. We present a simple model to illustrate how increased competition at sea, related to the release of large numbers of hatchery salmon, in conjunction with changes in ocean productivity, may have played a significant role in improving Sockeye Salmon survivals while reducing their growth before 1991. After 1991, these factors may have acted to reduce survivals while the growth of survivors showed no effect.Anadromous Pacific salmon Oncorhynchus spp. comprise a multispecies complex of varying productivities. Their recent abundance in the Pacific Ocean, as reflected by commercial catch, is as high as it has ever been (Irvine and Fukuwaka 2011). Global abundances are driven primarily by Pink Salmon O. gorbuscha and Chum Salmon O. keta, as well as, particularly in the eastern North Pacific Ocean, by Sockeye Salmon O. nerka (Eggers 2009;Ruggerone et al. 2010;Irvine and Fukuwaka 2011). The status of Sockeye Salmon populations varies among regions however, and in British Columbia's Fraser River, low Subject editor: Suam Kim, Pukyong National University, Busan, South Korea *Corresponding author: james.irvine@dfo-mpo.gc.ca Received February 8, 2013; accepted July 24, 2013 numbers of returning salmon in recent years are a major concern (Grant et al. 2011;Rand et al. 2012).The Fraser River watershed is one of the world's greatest salmon producers (Northcote and Larkin 1989), although numbers returning annually are highly variable...

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“…washington.edu/pdo/PDO.latest; Mantua and Hare 2002), the Aleutian Low Pressure Index (ALPI; Trenberth and Hurrell 1995), and the Northern Oscillation Index (NOI; Schwing et al 2002).…”

Section: Methodsmentioning

confidence: 99%

Understanding Smolt Survival Trends in Sockeye Salmon

Irvine

Akenhead

2013

Mar Coast Fish

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“…Weakening of subpolar and subtropical gyres decreases primary productivity (Schwing et al 2002;Behrenfeld et al 2006;Di Lorenzo et al 2008) and has been associated with decreased salmon abundance (Kilduff et al 2015), growth (Wells et al 2006), and body size (Jeffrey et al 2017) due to changes in prey species (Kaeriyama et al 2004). As a result of lower metabolic costs (Farley et al 2011;Siddon et al 2013), cooler temperatures have been shown to increase the growth potential of Pacific salmonids.…”

Section: Introductionmentioning

confidence: 99%

“…As a result of lower metabolic costs (Farley et al 2011;Siddon et al 2013), cooler temperatures have been shown to increase the growth potential of Pacific salmonids. Large-scale changes in ocean circulation and temperature are represented by climate indices such as Pacific Decadal Oscillation (PDO; related to sea surface temperature anomalies, linked to changes in salmon production; Mantua et al 1997), North Pacific Gyre Oscillation (NPGO; reflects changes in the intensity of circulation in the North Pacific gyre, a strong indicator of changes in the planktonic ecosystem; Di Lorenzo et al 2008), Northern Oscillation Index (NOI; based on sea surface height anomalies, dominated by El Niño and La Niña events; Schwing et al 2002), and Multivariate El Niño -southern oscillation (MEI; based on six oceanic and atmospheric variables, tracks El Niño and La Niña events; Wolter and Timlin 2011). Therefore, changes in climate indices may also explain the variation in growth patterns of Big Qualicum chum salmon.…”

Section: Introductionmentioning

confidence: 99%

Marine growth patterns of southern British Columbia chum salmon explained by interactions between density-dependent competition and changing climate

Debertin

Irvine

Holt

et al. 2017

Can. J. Fish. Aquat. Sci.

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Thirty-nine years of scale growth measurements from Big Qualicum River chum salmon (Oncorhynchus keta) in southern British Columbia demonstrated that competition and climate variation affect marine growth and age-at-maturity. A longitudinal study design that accounted for correlation among individuals revealed growth at all ages was reduced when the biomass of North American chum, sockeye (Oncorhynchus nerka), and pink salmon (Oncorhynchus gorbuscha) was high. When North Pacific Gyre Oscillation (NPGO) was positive, indicating increased primary productivity, predicted growth increased. Climate variation influenced competition effects. For instance, density-dependent competition effects increased when NPGO became more positive and Pacific Decadal Oscillation became more negative (indicating cool conditions), causing the greatest range in predicted scale size. Chum salmon are likely to exhibit continued reduction in growth at age due to increased ocean temperatures driven by climate change and high aggregate salmon biomass that includes hatchery releases. If evidence of biomass and climate effects presented here are common among Pacific salmon populations, reduction of hatchery releases should be considered. Résumé :Des mesures sur 39 ans de la croissance des écailles de saumons kétas (Oncorhynchus keta) de la Grande rivière Qualicum, dans le sud de la Colombie-Britannique, démontrent que la concurrence et les variations climatiques ont une incidence sur la croissance en mer et l'âge à la maturité. Un plan d'étude longitudinale qui tient compte de la corrélation entre individus révèle que la croissance à tous les âges est plus faible quand la biomasse des saumons kétas, sockeyes (Oncorhynchus nerka) et roses (Oncorhynchus gorbuscha) d'Amérique du Nord est élevée. Quand l'oscillation du tourbillon nord-pacifique (OTPN) est positive, indiquant une productivité primaire accrue, la croissance prédite augmente. Les variations du climat ont également une incidence sur ces effets de concurrence. Les effets de la concurrence dépendant de la densité augmentent quand l'OTPN devient plus positive et l'oscillation décennale du Pacifique, plus négative (indiquant des conditions fraîches), ce qui produit la plus grande fourchette de tailles d'écailles prédites. Il est probable que les saumons kétas continueront de présenter une diminution de la croissance selon l'âge en raison de la hausse des températures océaniques causée par les changements climatiques et de la forte biomasse totale de saumons incluant les individus issus d'écloseries. Si les indices d'effets de la biomasse et du climat relevés dans la présente étude s'avéraient répandus dans les populations de saumons du Pacifique, il serait pertinent d'examiner la possibilité de réduire les lâchers de poissons issus d'écloseries. [Traduit par la Rédaction]

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“…The extratropical-based Northern Oscillation index (NOI) and the extratropical-based Southern Oscillation index (SOI*) are characterized from sea level pressure anomalies of the North Pacific (NOI) or the South Pacific (SOI*). They reflect the variability in equatorial and extratropical teleconnections (Schwing et al (2002)). The Pacific/North American (PNA, Barnston & Livezey (1987)) an North Pacific (NP, Trenberth & Hurrell (1994)) indices reflect the air mass flows over the north pacific.…”

Section: Indicesmentioning

confidence: 83%

“…This index is used to explain sea-surface temperature anomalies in the equatorial regions. The Southern Oscillation Index (SOI, Schwing et al (2002)) is computed using the difference between the monthly mean sea level pressure anomalies at Tahiti and Darwin. The extratropical-based Northern Oscillation index (NOI) and the extratropical-based Southern Oscillation index (SOI*) are characterized from sea level pressure anomalies of the North Pacific (NOI) or the South Pacific (SOI*).…”

Section: Indicesmentioning

confidence: 99%