Habitat selection by juvenile coho salmon in response to food and woody debris manipulations in suburban and rural stream sections

2000 ◽  
Vol 57 (9) ◽  
pp. 1804-1813 ◽  
Author(s):  
Guillermo Roberto Giannico
Keyword(s):  
Habitat Selection ◽  
Coho Salmon ◽  
Woody Debris ◽  
Dominant Role ◽  
Oncorhynchus Kisutch ◽  
Late Summer ◽  
Abundant Food ◽  
Summer Distribution ◽  
Habitat Enhancement

This study explored the effects of food and woody debris manipulations on the summer distribution of juvenile coho salmon (Oncorhynchus kisutch) in small suburban streams. To examine fish responses to these factors, three different experiments were carried out in modified sections of two streams. The results showed that the distribution of juvenile coho salmon in a stream section was primarily controlled by the availability and distribution of food among pools and by the presence and density of woody debris. Food, however, played a dominant role because the foraging quality of a pool not only affected the density of fish in it but also the response of those fish towards instream debris. In food-rich stream sections, low proportions of juvenile coho salmon occupied pools with dense woody debris in the spring, which changed towards late summer. In contrast, in food-poor reaches, high proportions of fish were found in pools with abundant debris in the spring. Pools that combined abundant food with sparse woody debris were the most favoured by the fish. It is important that salmonid habitat enhancement projects consider that open foraging areas interspersed with woody debris characterize the type of summer habitat that juvenile coho salmon prefer.

Two generations of outbreeding in coho salmon (Oncorhynchus kisutch): effects on size and growth

2005 ◽  
Vol 62 (11) ◽  
pp. 2538-2547 ◽  
Author(s):  
Erin K McClelland ◽  
James M Myers ◽  
Jeffrey J Hard ◽  
Linda K Park ◽  
Kerry A Naish
Keyword(s):  
Growth Rates ◽  
Coho Salmon ◽  
Pacific Salmon ◽  
Oncorhynchus Kisutch ◽  
Late Summer ◽  
Early Life History ◽  
Lower Growth ◽  
Freshwater Aquaculture ◽  
In Captivity ◽  
Two Generations

Outbreeding is a potential genetic risk in Pacific salmon (Oncorhynchus spp.) when aquaculture practices introduce nonnative domesticated fish to wild environments, making interbreeding with wild populations possible. In this study, F1 and F2 hybrid families of coho salmon (Oncorhynchus kisutch) were created using a captive freshwater aquaculture strain and a locally derived hatchery population that is integrated with naturally spawning fish. Intermediate growth was detected in F1 and F2 hybrids from crosses reared in captivity; both generations had mean weight and length values between those of the parent populations after their first year (p < 0.05). In the early life history stages, maternal effects increased alevin growth in progeny of hatchery dams relative to those of captive dams (p < 0.001). Aquaculture control families showed greater growth rates than hybrids in late summer of their 1st year and in the following spring (p < 0.05), while the hatchery controls had lower growth rates during the first summer (p < 0.05). Line cross analysis indicated that changes in additive and dominance interactions, but not unfavorable epistatic interactions, likely explain the differences in weight, length, and growth rate observed in hybrids of these stocks of coho salmon.

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.

Effects of Sexual Maturation on the Quality of Coho Salmon (Oncorhynchus Kisutch) Flesh

1984 ◽  
Vol 17 (4) ◽  
pp. 271-273 ◽  
Author(s):  
E. Bilinski ◽  
R.E.E. Jonas ◽  
M.D. Peters ◽  
E.M. Choromanski
Keyword(s):  
Sexual Maturation ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch

Food abundance and fish density alters habitat selection, growth, and habitat suitability curves for juvenile coho salmon (Oncorhynchus kisutch)

2005 ◽  
Vol 62 (8) ◽  
pp. 1691-1701 ◽  
Author(s):  
Jordan S Rosenfeld ◽  
Thomas Leiter ◽  
Gerhard Lindner ◽  
Lorne Rothman
Keyword(s):  
Habitat Selection ◽  
Food Availability ◽  
Habitat Suitability ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Food Abundance ◽  
Fish Density ◽  
Invertebrate Drift ◽  
Stream Channels ◽  
Lower Growth

To understand how fish density and food availability affect habitat selection and growth of juvenile coho salmon (Oncorhynchus kisutch), we manipulated fish density (2–12 fish·m–2) and natural invertebrate drift (0.047–0.99 mg·m–3) in 12 experimental stream channels constructed in a side-channel of Chapman Creek, British Columbia. Increased food resulted in increased growth of both dominant and subdominant fish and a shift to higher average focal velocities (from 6.5 to 8.4 cm·s–1) with maximum growth in the range of 10–12 cm·s–1. Increased food appears to permit juvenile coho to exploit higher velocity microhabitats that might otherwise be bioenergetically unsuitable at lower food levels. Increased fish density resulted in lower growth of subdominant but not of dominant fish and a general displacement of fish to both higher and lower focal velocities. The shapes of habitat suitability curves were sensitive to food abundance, implying that differences in food availability may affect transferability of habitat suitability curves between streams of different productivity. While habitat suitability curves captured the change in extent of available habitat following prey enrichment, actual increases in growth rate with enrichment (i.e., changes in habitat quality) were poorly represented by habitat suitability values and better represented by bioenergetic model predictions.

Behaviour, Habitat Use, and Movements of Coho Salmon (Oncorhynchus kisutch) Smolte during Seaward Migration

1992 ◽  
Vol 49 (7) ◽  
pp. 1478-1485 ◽  
Author(s):  
Thomas E. McMahon ◽  
L. Blair Holtby
Keyword(s):  
British Columbia ◽  
Habitat Use ◽  
Coho Salmon ◽  
Saline Water ◽  
Woody Debris ◽  
Oncorhynchus Kisutch ◽  
Large Woody Debris ◽  
Seaward Migration

Coho salmon (Oncorhynchus kisutch) smolts formed aggregations in pools with large woody debris during their migration downstream and into the Carnation Creek estuary, British Columbia. Smolts utilized the estuary throughout the smolt run, with periods of high outmigration coinciding with spring tides which brought warmer, more saline water into the estuary. Smolt abundance in the stream and estuary was positively related to debris volume, and 82% of the 1260 smolts observed during underwater counts occurred within 1 m of debris. Debris volume and smolt density were significantly lower in clearcut than in buffered stream sections. Our observations support the need to retain and manage large woody debris for smolt habitat in streams and estuaries.

Advances in Fisheries Bioengineering

2008 ◽  
Keyword(s):  
Habitat Use ◽  
Coho Salmon ◽  
Woody Debris ◽  
Natural Habitat ◽  
Oncorhynchus Kisutch ◽  
Invertebrate Drift ◽  
Return Rates ◽  
Side Channels ◽  
Long Channel ◽  
Important Habitat

Abstract<em>.</em>—Side channels are recognized as an important habitat component for stream resident species such as coho salmon <em>Oncorhynchus kisutch</em>. The objectives of this study were to (1) design, construct, and monitor a natural-like channel for rearing coho salmon, and (2) demonstrate an alternative rearing technique that could be incorporated into hatchery operations. Data on migration, growth, habitat use, and ultimately return rates were collected. A 286-m-long channel containing riffles, pools, ponds, alcoves, and abundant large woody debris was constructed. Discharge was set at 0.1 m3/s and was adjustable from 0 to 0.3 m<sup>3</sup>/s. Channel width averaged 1.2 m and had a surface area of 971 m<sup>2</sup>. Invertebrate drift was supplemented with a prepared diet. Fifty thousand eyed coho eggs were incubated in the channel. The resulting fry were enumerated at the tail works and allowed to emigrate so that fish residence in the channel was volitional. Out-migration was high initially, dropped in the summer, and spiked over a 3-d period in the fall before slowing during winter followed by a distinct spring out-migration. Habitat use was quantified through visual counts, snorkeling, and underwater video. Densities of fish were approximately seven times higher than comparable natural habitat. Smolts leaving the channel in the spring equated to 1.5 fish/m<sup>2</sup>, which is higher than most comparable natural habitat. We concluded that engineered channels could volitionally support numbers of fish at densities higher than in natural habitat, that fish behavior in them was comparable to wild fish, and that engineered channels could be used by hatchery programs thus contributing to hatchery reform.

Habitat factors affecting the abundance and distribution of juvenile cutthroat trout (Oncorhynchus clarki) and coho salmon (Oncorhynchus kisutch)

2000 ◽  
Vol 57 (4) ◽  
pp. 766-774 ◽  
Author(s):  
Jordan Rosenfeld ◽  
Marc Porter ◽  
Eric Parkinson
Keyword(s):  
Coho Salmon ◽  
Woody Debris ◽  
Oncorhynchus Kisutch ◽  
Cutthroat Trout ◽  
Habitat Associations ◽  
Channel Width ◽  
Oncorhynchus Clarki ◽  
Small Stream ◽  
Factors Affecting ◽  
Small Streams

The distribution, abundance, and habitat associations of juvenile anadromous coastal cutthroat trout (Oncorhynchus clarki) and coho salmon (Oncorhynchus kisutch) were evaluated using survey data from 119 sites in coastal British Columbia. Both cutthroat and coho occurred at their highest densities in very small streams (<5 m channel width), and bankfull channel width was the single best predictor of cutthroat presence (p = 0.0001) and density (R2 = 0.55). Within a channel, densities of coho and larger (yearling and older) cutthroat parr were highest in pools, while densities of young-of-the-year cutthroat were significantly lower in pools and highest in shallower habitats. Abundance of larger cutthroat parr and pool habitat were positively correlated with large woody debris (LWD) within a subset of intermediate-gradient gravel-cobble streams, where pools appear to be limiting to larger cutthroat parr abundance. More than 50% of pools were formed by scour associated with LWD in streams ranging from 1.2 to 11 m channel width, and pools formed by LWD scour were on average 10% deeper than pools formed by other mechanisms. Disproportionate use of small streams by cutthroat indicates that protection of small stream habitat is important for long-term conservation of sea-run populations.

scholarly journals Roles of anthropogenic forcings in the observed trend of decreasing late-summer precipitation over the East Asian transitional climate zone

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Wei Zhao ◽  
Wen Chen ◽  
Shangfeng Chen ◽  
Hainan Gong ◽  
Tianjiao Ma
Keyword(s):  
Asian Summer Monsoon ◽  
Dominant Role ◽  
East Asian ◽  
Eastern China ◽  
Summer Precipitation ◽  
Late Summer ◽  
Water Vapor Transport ◽  
Anthropogenic Aerosol ◽  
Climate Zone ◽  
Drying Trend

AbstractObservations indicate that late-summer precipitation over the East Asian transitional climate zone (TCZ) showed a pronounced decreasing trend during 1951–2005. This study examines the relative contributions of anthropogenic [including anthropogenic aerosol (AA) and greenhouse gas (GHG)] and natural forcings to the drying trend of the East Asian TCZ based on simulations from CMIP5. The results indicate that AA forcing plays a dominant role in contributing to the drying trend of the TCZ. AA forcing weakens the East Asian summer monsoon via reducing the land-sea thermal contrast, which induces strong low-level northerly anomalies over eastern China, suppresses water vapor transport from southern oceans and results in drier conditions over the TCZ. In contrast, GHG forcing leads to a wetting trend in the TCZ by inducing southerly wind anomalies, thereby offsetting the effect of the AA forcing. Natural forcing has a weak impact on the drying trend of the TCZ due to the weak response of atmospheric anomalies.

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