scholarly journals Skagit River coho salmon life history model—Users’ guide

2017 ◽  
Author(s):  
Andrea Woodward ◽  
Grant Kirby ◽  
Scott Morris
2020 ◽  
Vol 650 ◽  
pp. 7-18 ◽  
Author(s):  
HW Fennie ◽  
S Sponaugle ◽  
EA Daly ◽  
RD Brodeur

Predation is a major source of mortality in the early life stages of fishes and a driving force in shaping fish populations. Theoretical, modeling, and laboratory studies have generated hypotheses that larval fish size, age, growth rate, and development rate affect their susceptibility to predation. Empirical data on predator selection in the wild are challenging to obtain, and most selective mortality studies must repeatedly sample populations of survivors to indirectly examine survivorship. While valuable on a population scale, these approaches can obscure selection by particular predators. In May 2018, along the coast of Washington, USA, we simultaneously collected juvenile quillback rockfish Sebastes maliger from both the environment and the stomachs of juvenile coho salmon Oncorhynchus kisutch. We used otolith microstructure analysis to examine whether juvenile coho salmon were age-, size-, and/or growth-selective predators of juvenile quillback rockfish. Our results indicate that juvenile rockfish consumed by salmon were significantly smaller, slower growing at capture, and younger than surviving (unconsumed) juvenile rockfish, providing direct evidence that juvenile coho salmon are selective predators on juvenile quillback rockfish. These differences in early life history traits between consumed and surviving rockfish are related to timing of parturition and the environmental conditions larval rockfish experienced, suggesting that maternal effects may substantially influence survival at this stage. Our results demonstrate that variability in timing of parturition and sea surface temperature leads to tradeoffs in early life history traits between growth in the larval stage and survival when encountering predators in the pelagic juvenile stage.


2010 ◽  
Vol 67 (3) ◽  
pp. 486-497 ◽  
Author(s):  
Véronique Thériault ◽  
Gregory R. Moyer ◽  
Michael A. Banks

Survival and life history characteristics were evaluated for a coho salmon ( Oncorhynchus kisutch ) integrated hatchery program using two stocking strategies. Fish were released as unfed fry or smolts and returned as adults, and then molecular analysis was employed to pedigree the entire population. We showed that mean adult survival of individuals released as unfed fry was less than that of individuals released as smolts (0.03% vs. 2.39%). The relative reproductive success (RRS) of the fry release strategy to wild spawning was significantly greater for one of two cohorts, whereas the smolt release strategy to wild RRS was significantly greater for both cohorts. Fish released as smolts were significantly smaller upon returning as adults than either those released as unfed fry or wild returns. Mean run timing was also significantly biased towards an earlier run time for hatchery-released fish when compared with the wild component. The incidence of jacking (males maturing at age 2) was greater among fish stocked as smolts than for fish stocked as fry. Differences in survival, RRS, and life history appeared to be the result of hatchery practices and indicated that a fry stocking strategy produced fish more similar to the wild component of the population than to that of fish released as smolts.


2015 ◽  
Vol 72 (5) ◽  
pp. 684-696 ◽  
Author(s):  
Gary E. Johnson ◽  
Gene R. Ploskey ◽  
Nichole K. Sather ◽  
David J. Teel

We documented two life history strategies for juvenile salmonids as expressed in off-channel tidal freshwater habitats of the Columbia River: (i) active migrations by upper river Chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss) during the primary spring and summer migration periods and (ii) overwinter rearing in tidal freshwater habitats by coho salmon (Oncorhynchus kisutch) and naturally produced Chinook salmon mostly from lower river sources. During spring–summer 2007–2008, acoustic-tagged fish originating above Bonneville Dam (rkm 234) had short residence times in off-channel areas (rkm 192–203): median 2.5 and 2.6 h for yearling (mean lengths 134 and 158 mm) and 3.0 and 3.4 h for subyearling (104 and 116 mm) Chinook salmon and 2.5 h for yearling steelhead (215 mm). The percentage of fish in off-channel areas out of the total in the main- and off-channels areas was highest for yearling Chinook salmon (8.1% and 9.3% for 2007 and 2008, respectively) and lowest for steelhead (4.0% for 2008) and subyearling Chinook salmon (3.6% and 6.1% for 2007 and 2008, respectively). In late January and early February 2010, 2011, and 2012, we captured and tagged yearling Chinook and coho salmon occupying off-channel tidal freshwater habitats. Median residence times in off-channel areas were 11.6–25.5 days for juvenile Chinook (106, 115, and 118 mm, respectively by year) and 11.2 days for coho salmon (116 mm). This study is the first to estimate residence times for juvenile salmonids specifically in off-channel areas of tidal fresh water and, most importantly, residence times for Chinook salmon expressing a life history of overwintering in tidal fresh water. The findings support restoration of shallow off-channel habitats in tidal freshwater portions of the Columbia River.


2015 ◽  
Vol 103 ◽  
pp. 71-83 ◽  
Author(s):  
H. Andres Araujo ◽  
Andrew B. Cooper ◽  
Erland A. MacIsaac ◽  
Duncan Knowler ◽  
Antonio Velez-Espino

2015 ◽  
Vol 144 (3) ◽  
pp. 627-641 ◽  
Author(s):  
Mara S. Zimmerman ◽  
Clayton Kinsel ◽  
Eric Beamer ◽  
Edward J. Connor ◽  
David E. Pflug

1989 ◽  
Vol 15 (2) ◽  
pp. 109-125 ◽  
Author(s):  
Gary K. Ostrander ◽  
Marsha L. Landolt ◽  
Richard M. Kocan

2020 ◽  
Vol 13 (6) ◽  
pp. 1501-1512 ◽  
Author(s):  
Kyle A. Young ◽  
Victoria A. Cluney ◽  
Laura K. Weir

2008 ◽  
Vol 65 (4) ◽  
pp. 681-690 ◽  
Author(s):  
William L Reichert ◽  
Correigh M Greene ◽  
Robert E Bilby

Salmon carcasses provide a marine derived nutrient (MDN) subsidy to river systems, but the extent to which it affects juvenile salmon growth is unclear. To evaluate temporal and spatial nutrient contributions from watershed sources and MDNs using stable isotopes, Skagit River (Washington, USA) juvenile coho salmon (Oncorhynchus kisutch) were collected. Muscle samples were taken from fry through smolts to measure temporal changes in δ15N and δ13C. δ15N and δ13C levels declined from emergence until fall, when they approached values for resident cutthroat trout (Oncorhynchus clarkii) collected above anadromous barriers. Muscle δ13C was highly variable and did not increase subsequently. However, coho salmon δ15N increased during the winter. March coho salmon parr δ15N levels suggested high variability in carcass availability for consumption. During the next spring, δ15N levels again declined. In Griffin Creek, a Snoqualmie River tributary, a significant relationship between carcass density and δ15N and δ13C levels was found in March coho salmon parr. At high spawner densities, some parr δ15N exceeded carcass values; however, parr δ13C increased moderately. These findings show that stable isotope data provide insights on seasonal sources of nutrients. In addition, results indicate that March coho salmon parr δ15N levels would be a useful index of carcass availability for overwintering juvenile consumption.


1981 ◽  
Vol 38 (12) ◽  
pp. 1481-1496 ◽  
Author(s):  
Ross M. Horrall

A moderately high degree of reproductive isolation is necessary for the formation and maintenance of discrete stocks of fish. This reproductive isolation can be developed through spawning site imprinting and homing—behavioral mechanisms that are apparently very common in fish. During some part of their early life history, the fish become imprinted to, or conditioned to, environmental characteristics of the spawning site and/or to the pheromonal characteristics of their stock. At sexual maturity, they show an orientation-homing behavior back to the natal area where spawning then occurs reinitiating the cycle. Over time, stock-specific adaptations are made to the local environment which can involve changes in the morphological, physiological, or behavioral characteristics of the fish. Research on salmonids has provided the best evidence for site imprinting and natal homing in fish. Tagging and transplantation experiments with these species have been especially important sources of information. In coho salmon (Oncorhynchus kisutch), olfactory homing and olfactory site imprinting have been demonstrated by artificial imprinting techniques; it was found that the critical period for imprinting occurred during smoltification at an age of 15 or 16 mo. Most species do not undergo smolting, and imprinting occurs at a very early stage in the life history. It is hypothesized that the information which is imprinted about the natal site may be obtained from one or more of the following: odors in the water flowing over the site; odors originating from the site itself; and stock-specific pheromones emitted directly from the fish or from their waste products. Differences in characteristics of homing and imprinting in relation to the formation and maintenance of stocks are discussed for several Great Lake species including coho salmon, pink salmon (O. gorbuscha), lake trout (Salvelinus namaycush), white bass (Morone chrysops), and walleye (Stizostedion vitreum vitreum). Inferences are made about how these characteristics relate to the rehabilitation of fish stocks in the Great Lakes and their tributaries.Key words: stock-isolating mechanisms, Great Lakes fish, homing, site imprinting


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