Seasonal variations in stable isotope ratios of juvenile coho salmon (Oncorhynchus kisutch) from western Washington rivers

2008 ◽  
Vol 65 (4) ◽  
pp. 681-690 ◽  
Author(s):  
William L Reichert ◽  
Correigh M Greene ◽  
Robert E Bilby
Keyword(s):  
Stable Isotope ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Cutthroat Trout ◽  
Oncorhynchus Clarkii ◽  
Western Washington ◽  
Temporal And Spatial ◽  
Salmon Parr ◽  
Skagit River ◽  
Salmon Carcasses

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.

Empirical relationships between watershed characteristics and coho salmon (Oncorhynchus kisutch) smolt abundance in 14 western Washington streams

2001 ◽  
Vol 58 (7) ◽  
pp. 1453-1463 ◽  
Author(s):  
Rishi Sharma ◽  
Ray Hilborn
Keyword(s):  
Coho Salmon ◽  
Woody Debris ◽  
Oncorhynchus Kisutch ◽  
Empirical Relationships ◽  
Watershed Characteristics ◽  
Valley Slope ◽  
Two Measures ◽  
Western Washington ◽  
Lower Stream ◽  
Habitat Variables

We assembled data on coho salmon (Oncorhynchus kisutch) from 14 streams in western Washington, including annual smolt counts and annual escapement, either as absolute counts or as an index. We also compiled data on large woody debris (number·km%#150;1 of stream), road densities in the watersheds (km road·km%#150;2), gradient of the streams (%), valley slope adjacent to the stream (%), drainage area in the watershed (km2), and pool, pond, and lake areas (m2·km%#150;1). We explored the relationships between habitat variables and two measures of coho production, the maximum production of smolts in the stream (capacity) and the maximum smolts/spawner (productivity). Using the 11 streams with pool and pond counts, we found that pool and pond densities served as good predictors of smolt density (r2 = 0.85 for pools and 0.68 for ponds, independently). Pools produced 0.39 smolts·m%#150;2 and ponds produced 0.07 smolts·m%#150;2 in the multiple regression fit, accounting for 92% of the residual error. We also found that lower valley slopes, lower road densities, and lower stream gradients were correlated with higher smolt density.

scholarly journals Lunar cycles of coho salmon, Oncorhynchus kisutch. I. Growth and feeding

1987 ◽  
Vol 129 (1) ◽  
pp. 165-178
Author(s):  
K. J. Farbridge ◽  
J. F. Leatherland
Keyword(s):  
Growth Rate ◽  
Coho Salmon ◽  
Slow Growth ◽  
Oncorhynchus Kisutch ◽  
Relative Length ◽  
Lunar Cycle ◽  
Relative Mass ◽  
Cyclic Patterns ◽  
Lunar Cycles ◽  
Salmon Parr

Coho salmon (Oncorhynchus kisutch Walbaum) parrs and smolts, maintained in a laboratory under a fixed artificial 12 h light:12 h dark photoperiod from the time of hatching, exhibited a pattern of alternating periods of rapid and slow growth in body mass; the peaks and troughs in growth rate were significantly different from one another. The alternating growth rate changes were rhythmic in nature, of approximately 14 to 15 days in length. Evidence for cyclic patterns of growth in relative length and in food consumption was also found in coho salmon parr. Peak food intake appeared to occur 2–4 days after each peak of growth in relative mass. Although the pattern of growth in relative length was less clear, there was evidence to suggest that growth in length might be out of phase with growth in mass. There was no pattern of cycling growth rates in coho salmon parr subsampled from a common stock. The significance of this is discussed. The data suggest that the lunar cycle acts as a Zeitgeber for synchronization of the growth rate rhythms.

Overwintering habitats of coho salmon (Oncorhynchus kisutch) and other juvenile salmonids in the Keogh River system, British Columbia

1988 ◽  
Vol 66 (1) ◽  
pp. 254-261 ◽  
Author(s):  
S. Swales ◽  
F. Caron ◽  
J. R. Irvine ◽  
C. D. Levings
Keyword(s):  
Gasterosteus Aculeatus ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Cutthroat Trout ◽  
River System ◽  
Salmo Gairdneri ◽  
Dolly Varden Char ◽  
Main River ◽  
The Mean ◽  
Density And Biomass

Catches of overwintering juvenile coho salmon (Oncorhynchus kisutch) in the Keogh River system, Vancouver Island, were higher in two small (8 and 25 ha), shallow (mean depth 2 – 3 m) lakes and their outlet and inlet streams than in the main river, where steelhead trout (Salmo gairdneri) were predominant. Dolly Varden char (Salvelinus malma), cutthroat trout (Salmo clarki), and threespine stickleback (Gasterosteus aculeatus) were also present in the lakes. The distribution of coho salmon in the lakes was restricted largely to areas close to the bank, with few fish being captured in offshore areas or in mid-water. Apparent differences in the abundance of coho salmon between the two lakes may have been related to differences in fish community composition, with sticklebacks being particularly numerous in Misty Lake, where catches of coho salmon were lower than in Long Lake. The population density and biomass of coho salmon overwintering in Long Lake were estimated to be 176 fish/ha and 1.14 kg ha−1, respectively. The mean length of coho salmon in the lakes was greater than that of coho salmon in the tributary streams and main river, and the mean length of the salmon in the lakes generally increased with distance away from shore.

Response of juvenile coho salmon (Oncorhynchus kisutch) and steelhead (Oncorhynchus mykiss) to the addition of salmon carcasses to two streams in southwestern Washington, U.S.A.

1998 ◽  
Vol 55 (8) ◽  
pp. 1909-1918 ◽  
Author(s):  
Robert E Bilby ◽  
Brian R Fransen ◽  
Peter A Bisson ◽  
Jason K Walter
Keyword(s):  
Oncorhynchus Mykiss ◽  
Coho Salmon ◽  
Isotope Analysis ◽  
Oncorhynchus Kisutch ◽  
Stomach Contents ◽  
Similar Increase ◽  
Reference Sites ◽  
Food Items ◽  
Small Streams ◽  
Salmon Carcasses

Availability of organic matter and nutrients transported from the marine environment to streams by spawning salmon was increased in two small streams in southwestern Washington, U.S.A., by adding salmon carcasses from a nearby hatchery. Response of juvenile coho salmon (Oncorhynchus kisutch) and steelhead (Oncorhynchus mykiss) rearing at these sites was compared with nearby streams where few salmon spawned. Densities of age 0+ coho salmon and age 0+ and age 1+ steelhead increased following carcass additions to the treated streams. A similar increase in density was not observed at the reference sites. Condition factors in treated streams increased following carcass addition and remained at high levels while carcasses were present whereas no similar pattern was observed at the reference sites. Stomach contents of fish in streams to which carcasses had been added consisted primarily of salmon eggs and carcass flesh when carcasses were present in the stream. Stable isotope analysis indicated that the proportion of marine-derived nitrogen in the muscle tissue of juvenile salmonids increased as much as 39% following carcass placement. Results suggest that eggs and carcasses of adult salmon provide a very important resource during a period when other food items are often scarce.

Juvenile coho salmon (Oncorhynchus kisutch) responses to salmon carcasses and in-stream wood manipulations during winter and spring

2007 ◽  
Vol 64 (2) ◽  
pp. 324-335 ◽  
Author(s):  
Guillermo R Giannico ◽  
Scott G Hinch
Keyword(s):  
Growth Rates ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Fish Growth ◽  
Winter Survival ◽  
Survival Pattern ◽  
Experimental Trials ◽  
Fish Survival ◽  
Individual Body ◽  
Salmon Carcasses

We investigated the growth rate, winter survival, presmolt size, and emigration timing of juvenile coho salmon (Oncorhynchus kisutch) in response to salmon carcasses and in-stream wood. Experimental trials were conducted during two consecutive years and pre-winter fish size and densities differed between years. Sixteen pens with emigration traps were built in a side-channel of the Mamquam River, British Columbia. Pens were randomly assigned salmon carcasses, in-stream wood, both carcasses and in-stream wood, or neither (control). Our first trial was conducted between December 1996 and August 1997 and the second between December 1997 and August 1998. Initial rearing densities and average individual body mass were 3.1 fish·m–2 and 2.4 g, respectively, in the first trial and were 1.6 fish·m–2 and 6.6 g, respectively, in the second trial. Results were influenced by both fish initial size and density. During the first trial (smaller-sized fish at high densities), salmon carcasses increased fish growth rates and presmolt size. Winter survival did not increase in response to any treatment; however, a pre-winter size-related survival pattern was observed during the first trial. During the second trial, (larger-sized fish at low densities), no treatment influenced fish growth rates or presmolt size but all treatments augmented fish survival.

The influence of fall-spawning coho salmon (Oncorhynchus kisutch) on growth and production of juvenile coho salmon rearing in beaver ponds on the Copper River Delta, Alaska

2006 ◽  
Vol 63 (4) ◽  
pp. 917-930 ◽  
Author(s):  
Dirk W Lang ◽  
Gordon H Reeves ◽  
James D Hall ◽  
Mark S Wipfli
Keyword(s):  
Growth Rates ◽  
Feedback Loop ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
River Delta ◽  
Short Term ◽  
Beaver Ponds ◽  
Copper River Delta ◽  
The Relationship ◽  
Salmon Carcasses

This study examined the influence of fall-spawning coho salmon (Oncorhynchus kisutch) on the density, growth rate, body condition, and survival to outmigration of juvenile coho salmon on the Copper River Delta, Alaska, USA. During the fall of 1999 and 2000, fish rearing in beaver ponds that received spawning salmon were compared with fish from ponds that did not receive spawners and also with fish from ponds that were artificially enriched with salmon carcasses and eggs. The response to spawning salmon was variable. In some ponds, fall-spawning salmon increased growth rates and improved the condition of juvenile coho salmon. The enrichment with salmon carcasses and eggs significantly increased growth rates of fish in nonspawning ponds. However, there was little evidence that the short-term growth benefits observed in the fall led to greater overwinter growth or survival to outmigration when compared with fish from the nonspawning ponds. One potential reason for this result may be that nutrients from spawning salmon are widely distributed across the delta because of hydrologic connectivity and hyporheic flows. The relationship among spawning salmon, overwinter growth, and smolt production on the Copper River Delta does not appear to be limited entirely to a simple positive feedback loop.

Preferences of Juvenile Coho Salmon (Oncorhynchus kisutch) and Cutthroat Trout (Salmo clarki) Relative to Simulated Alteration of Winter Habitat

1975 ◽  
Vol 32 (5) ◽  
pp. 681-687 ◽  
Author(s):  
David R. Bustard ◽  
David W. Narver
Keyword(s):  
Coho Salmon ◽  
Habitat Preferences ◽  
Oncorhynchus Kisutch ◽  
Cutthroat Trout ◽  
Strong Preference ◽  
Winter Habitat ◽  
Before And After ◽  
Salmo Clarki

Winter habitat preferences of juvenile coho salmon (Oncorhynchus kisutch) and cutthroat trout (Salmo clarki) were tested by simulating conditions before and after stream disturbance such as might result from logging: (1) sidepools with or without an overhanging bank and roots, and (2) sidepools with clean or silted rubble substrate. Both coho and cutthroat demonstrated a strong preference for sidepools offering overhanging bank cover as opposed to those without bank cover. Similarly they preferred sidepools with clean rubble substrate as opposed to silted rubble. In both the bank and rubble tests, when given the option of either remaining in the sidepools or of moving into the stream, a greater percentage of the total number of coho and cutthroat originally in the sidepools remained in the pools with cover as opposed to those without cover. Coho utilized bank cover more readily than rubble cover whereas cutthroat used both bank and rubble cover.

Summer movement and growth of juvenile anadromous salmonids in small western Washington streams

2001 ◽  
Vol 58 (10) ◽  
pp. 1947-1956 ◽  
Author(s):  
Thomas H Kahler ◽  
Philip Roni ◽  
Thomas P Quinn
Keyword(s):  
Coho Salmon ◽  
Cutthroat Trout ◽  
Habitat Choice ◽  
Small Scale ◽  
Steelhead Trout ◽  
Oncorhynchus Clarki Clarki ◽  
Mobile Fraction ◽  
Western Washington ◽  
Channel Type ◽  
Downstream Movement

Movements of juvenile coho salmon (Oncorhynchus kisutch), cutthroat trout (Oncorhynchus clarki clarki), and steelhead trout (Oncorhynchus mykiss) were studied by observations and recapture of marked individuals in three western Washington streams to test the hypotheses that few fish would move, downstream movement would predominate, movers would be initially smaller and grow slower after movement than residents, and habitat quality would influence movement. Contrary to predictions, from 28 to 60% of marked fish moved at least one habitat unit, and immigration of unmarked fish also indicated considerable movement. Upstream movement predominated but the stream with the step-pool/cascade channel type had fewer upstream movers and greater distances moved downstream. Coho movers were not smaller than nonmovers, as predicted based on assumptions that movement results from competitive exclusion. Habitat units that coho left were smaller and shallower but lower in density than units where coho remained. Thus, movement is a common phenomenon rather than an aberration, and may reflect habitat choice rather than territorial eviction. Moreover, movers grew faster than nonmovers, so the "mobile fraction" of the population was not composed of competitively inferior fish but rather individuals that thrived. The phenomenon of small-scale habitat- and growth-related movements should be considered when planning and interpreting studies of juvenile salmonid ecology in streams.

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