Abstract Numerical abundance and biomass values presented here for Pink Salmon Oncorhynchus gorbuscha , Chum O. keta Sockeye nerka in the North Pacific Ocean span 90 years (1925–2015), representing most comprehensive compilation of these data to date. In contrast less populous species salmon, are more abundant now than ever, averaging 665 × 10 6 adult salmon each year (1.32 metric tons) during 1990–2015. When immature included, recent estimates approach 5 tons. Following an initial peak...

Abstract Irvine, J. R., and Fukuwaka, M. 2011. Pacific salmon abundance trends climate change. – ICES Journal of Marine Science, 68: 1122–1130. Understanding reasons for historical patterns in could help anticipate future climate-related changes. Recent the northern North Ocean, as indexed by commercial catches, has been among highest on record, with no indication decline; 2009 catch was to date. Although Ocean continues produce large quantities salmon, temporal vary species areas....

Abstract Understanding the factors contributing to declining smolt‐to‐adult survival (hereafter “smolt survival”) of Coho Salmon Oncorhynchus kisutch originating in Salish Sea southwestern British Columbia and Washington State is a high priority for fish management agencies. Uncertainty regarding relative importance mortality operating at different spatial scales hinders prioritization science activities. We therefore examined temporal coherence smolt survivals based on decision tree...

Abstract Species redistributions, whether resulting from invasions or range expansions, pose similar challenges for conservation and management. Redistribution impacts on host ecosystems species combine with those climate change, which are already acute at northern latitudes. Using pink salmon Oncorhynchus gorbuscha, native to the Pacific Ocean, we employ knowledge exchange inform decision-making in non-native marine areas: they expanding their Arctic Ocean invasive Atlantic Ocean. The...

We investigated a recent, major decline in the abundance of large aggregate coho salmon (Oncorhynchus kisutch) spawning Thompson River, British Columbia, watershed. found that could be attributed to declining trend productivity likely related changing ocean conditions, overfishing, and freshwater habitat alteration. Among individual watersheds, rates adult were correlated with agricultural land use, road density, qualitative measure stream status but not proportion recently logged. The...

Salmon spawning escapements are estimated using the area-under-the-curve (AUC) method by dividing integral of escapement curve average residence time fish in survey area. We present two forms basic AUC which differ procedure used to estimate from observations tagged during stream surveys. estimates based on "observed times" were sensitive variability timing, observer efficiency, and tag detection, while those "total more robust. For coastal streams, between 1.1, 6.8 times larger than an...

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 (Oncorhynchus nerka) populations, we present evidence that the magnitude direction of climate competition vary over large spatial scales. In south, a warm abundant competitors to strongly reduce productivity, whereas in north, substantially increased offset negative at sea. From 2005 2015, approximately 82...

Abstract The North Pacific Ocean is warming and overall salmon abundance higher now than at any other time in the past century. This increase large part due to warming-related changes marine ecosystems northern latitudes that primarily benefit pink salmon, industrial-scale hatchery production support commercial fisheries. A body of evidence indicates increasing more variable ocean temperatures, as well competition among sea, are associated with shifts productivity, size, age maturation....

We describe a method of estimating the spawning escapement coho salmon (Oncorhynchus kisutch) from capture–recapture data. Traditional analyses do not directly provide estimates escapements; however, we show how simple modifications to Jolly–Seber can estimate total number fish returning river including those that enter and die between sampling occasions. Spawning runs Pacific were simulated their escapements estimated using capture–recapture. The performance maximum likelihood estimators...

Initial stream flow changes after a period of constant have much larger effect on invertebrate drift than subsequent changes. Constant discharge was maintained in two man-made streams for several months, which kept one (control) while the other (treatment) it increased fivefold and then returned to its original state three times between 17:00 21:00 1 d. This treatment repeated four successive days each week 3 wk. On first day density during discharge, increase being less with change. By...

Body size can sometimes change rapidly as an evolutionary response to selection or a phenotypic changes in environmental conditions. Here, we revisit classic case of rapid body five species Pacific salmon (Oncorhynchus spp.) caught Canadian waters, with six-decade analysis (1951–2012). Declines at maturity up 3 kg Chinook tshawytscha) and 1 coho kisutch) during the 1950s 1960s were later reversed match exceed earlier sizes. In contrast, there has been little sockeye nerka) sizes initial...

Abstract Variation at eight microsatellite loci and two linked exons of a major histocompatibility complex (MHC) locus was surveyed in approximately 21,000 coho salmon Oncorhynchus kisutch sampled from 138 localities ranging southeast Alaska to the Columbia River, majority sites being British Columbia. The observed regional population structure enabled evaluation utility using MHC variation for estimating stock composition mixed-stock fisheries. Both were more effective identification than...

Abstract: Although there are many indicators of endangerment (i.e., whether populations or species meet criteria that justify conservation action), their reliability has rarely been tested. Such may fail to identify a population meets for action (false negative) incorrectly show such have met positive). To quantify the rate both types error 20 commonly used declining abundance (threat indicators), we receiver operating characteristic curves derived from historical (1938–2007) data 18 sockeye...

Abstract 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 mechanisms responsible. To better understand survival trends, we examined 50‐year time series for two age‐classes smolts from Chilko Lake central British Columbia. Arranging both by ocean entry year and combining them, weighted a proxy model sampling variance, reduced variance original age‐1 smolt...

We describe a simple scheme for the management of coho salmon (Oncorhynchus kisutch) population aggregates that uses reference points derived from an empirical analysis freshwater production data. fit rectilinear "hockey stick" model to 14 historical data sets female spawner abundance and resulting smolt found at low abundance, average productivity was about 85 smolts per spawner. Variation in among streams may be related quality stream habitat. show how can combined with forecasts marine...

Groups of about 10,000 smolts coho salmon Oncorhynchus kisutch were marked with one two types fluorescent tags: visible implant filament (VIF) and elastomer (VIE). Fish also tagged coded wire tags adipose fin clipped to assess tag retention marine survival. Ocean recoveries reported through the coastwide mark–recovery database. Returning fish examined for presence tags, survival exploitation data compared among groups. Fluorescent in approximately 90% bearing them easily seen natural light....

Abstract An experiment with flow changing at 3, 9, and 18 m3 s‐1 h‐1 on consecutive days failed to produce any measurable effect benthic invertebrates in the regulated Hawea River, New Zealand, but did result increased numbers of drifting chironomid larvae, trichopteran oligochaetes compared when was stable. Drift densities were least as high day changed 3 (minimum 15 s‐1, maximum 30 s‐1) subsequent 9 flows both 60 105 respectively) indicating that rapid rates change may not necessarily...

Concern about the decline of wild salmon has attracted attention International Union for Conservation Nature (IUCN). The IUCN applies quantitative criteria to assess risk extinction and publishes its results on Red List Threatened Species. However, focus is species level thus may fail show populations. adapted their apply populations but there exist few examples this type assessment. We assessed status sockeye Oncorhynchus nerka as a model application population-level assessments provide...

Altering release sizes and timings of coho salmon smolts from hatcheries in the Strait Georgia will not reverse precipitous survival declines past three decades. We modeled effects on ocean entry year, mean smolt size (weight), day. Ocean year was by far most important. During 1979–2006, to adult survivals declined similarly for hatchery wild salmon, although consistently survived at higher rates. Best models differed among hatcheries, implying location-specific differences optimal timing...

Some of the consequences varying flows on downstream migration salmon fry were investigated in five replicate streams adjacent to lower Waitaki River, New Zealand. Fluctuating discharge appeared increase number moving downstream, provided that mean water velocities at peak exceeded 25 cms −1 ’and some migrating out anyway. Salmonids appear have a lengthier flow–sensitive period than has been proposed literature. Research is required determine whether recently emerged leave parental spawning...

Oncorhynchus nerka occur both as anadromous sockeye salmon that spend most of their life in the ocean, and non-anadromous kokanee remain fresh water entire lives. We assessed whether stable isotopes sulfur (δ34S) otoliths could be used to distinguish ecotypes are otherwise difficult identify when they share a common freshwater rearing environment. also investigated chemical link between diet by measuring δ34S various fish tissues (eggs, muscle, scales) zooplankton. (mean±SE) eggs (18.7 ±...

A novel semiparametric model that can incorporate environmental and fishery data is developed to analyze stock–recruitment relationships. Unlike traditional models assume a log-linear relationship between recruitment variables, the new uses nonparametric smoothing algorithm, which helps quantify underlying empirical relationships enables more accurate parameter estimates. Bootstrap resampling used evaluate uncertainties in parameters. Distribution plots be produced for productivity capacity...