Density and size of juvenile salmonids in response to placement of large woody debris in western Oregon and Washington streams

2001 ◽  
Vol 58 (2) ◽  
pp. 282-292 ◽  
Author(s):  
Philip Roni ◽  
Thomas P Quinn
Keyword(s):  
Coho Salmon ◽  
Woody Debris ◽  
Cutthroat Trout ◽  
Large Woody Debris ◽  
Response To Treatment ◽  
Oncorhynchus Clarki ◽  
Steelhead Trout ◽  
Density Response ◽  
Total Pool ◽  
Pool Area

Thirty streams in western Oregon and Washington were sampled to determine the responses of juvenile salmonid populations to artificial large woody debris (LWD) placement. Total pool area, pool number, LWD loading, and LWD forming pools were higher in treatment (LWD placement) than paired reference reaches during summer or winter. Juvenile coho salmon (Oncorhynchus kisutch) densities were 1.8 and 3.2 times higher in treated reaches compared with reference reaches during summer and winter, respectively. The response (treatment minus reference) of coho density to LWD placement was correlated with the number of pieces of LWD forming pools during summer and total pool area during winter. Densities of age-1+ cutthroat trout (Oncorhynchus clarki) and steelhead trout (Oncorhynchus mykiss) did not differ between treatment and reference reaches during summer but were 1.7 times higher in treatment reaches during winter. Age-1+ steelhead density response to treatment during summer was negatively correlated with increases in pool area. Trout fry densities did not differ between reaches, but the response of trout fry to treatment was negatively correlated with pool area during winter. Our research indicates that LWD placement can lead to higher densities of juvenile coho during summer and winter and cutthroat and steelhead during winter.

Effects of increasing winter rearing habitat on abundance of salmonids in two coastal Oregon streams

2000 ◽  
Vol 57 (5) ◽  
pp. 906-914 ◽  
Author(s):  
M F Solazzi ◽  
T E Nickelson ◽  
S L Johnson ◽  
J D Rodgers
Keyword(s):  
Coho Salmon ◽  
Woody Debris ◽  
Cutthroat Trout ◽  
Stream Habitat ◽  
Oncorhynchus Clarki ◽  
Winter Habitat ◽  
Coastal Cutthroat Trout ◽  
Posttreatment Period ◽  
Complex Habitat ◽  
Downstream Migrant

We used a BACI (before-after-control-impact) experimental design to examine the effects of increasing winter habitat on the abundance of downstream migrant salmonids. Two reference streams and two treatment streams were selected in the Alsea and Nestucca basins of Oregon. Population parameters for juvenile coho salmon (Oncorhynchus kisutch), age-0 trout (Oncorhynchus spp.), steelhead (Oncorhynchus mykiss), and coastal cutthroat trout (Oncorhynchus clarki) were estimated each year for 8 years in each stream. Stream habitat was modified to increase the quality and quantity of winter habitat during the summers of 1990 (Nestucca Basin) and 1991 (Alsea Basin). Complex habitat was constructed by adding large woody debris to newly created alcoves and dammed pools. Numbers of coho salmon summer juveniles and smolts increased in the treatment streams relative to the control streams during the posttreatment period. Overwinter survival of juvenile coho salmon also increased significantly in both treatment streams posttreatment. Summer trout populations in the treatment streams did not change, but downstream migrant numbers the following spring did increase. These increases suggest that winter habitat was limiting abundance of all three species.

Influence of large woody debris on retention, immigration, and growth of coastal cutthroat trout (Oncorhynchus clarki clarki) in stream pools

1998 ◽  
Vol 55 (8) ◽  
pp. 1902-1908 ◽  
Author(s):  
Bret C Harvey
Keyword(s):  
Woody Debris ◽  
Cutthroat Trout ◽  
Second Order ◽  
Large Woody Debris ◽  
Anadromous Fish ◽  
Oncorhynchus Clarki ◽  
Third Order ◽  
The Third ◽  
Oncorhynchus Clarki Clarki ◽  
Coastal Cutthroat Trout

Over 4 months and about 1 year, coastal cutthroat trout (Oncorhynchus clarki clarki) age-1 in Little Jones Creek, California, remained at similar rates in pools with and without large woody debris. This result was based on attempts in July and November 1995 to collect and tag all fish in 22 pools and three collections of fish from the same pools in November 1995, May 1996, and August 1996. Retention of fish appeared to be greater in pools with large woody debris in May 1996. The presence of large woody debris in pools did not influence immigration or growth of cutthroat trout. However, both immigration and growth increased downstream over the 3850-m study reach. Low retention and substantial immigration of cutthroat trout into experimental pools indicate that movement is important in the dynamics of this population. First- and second-order channels appear to be important sources of fish for the third-order study reach, while the study reach may export significant numbers of fish to downstream reaches accessible to anadromous fish.

Influence of large woody debris and a bankfull flood on movement of adult resident coastal cutthroat trout (Oncorhynchus clarki) during fall and winter

1999 ◽  
Vol 56 (11) ◽  
pp. 2161-2166 ◽  
Author(s):  
Bret C Harvey ◽  
Rodney J Nakamoto ◽  
Jason L White
Keyword(s):  
Habitat Complexity ◽  
Woody Debris ◽  
Cutthroat Trout ◽  
Main Channel ◽  
Large Woody Debris ◽  
Oncorhynchus Clarki ◽  
Stream Fishes ◽  
Adult Fish ◽  
Coastal Cutthroat Trout

To improve understanding of the significance of large woody debris to stream fishes, we examined the influence of woody debris on fall and winter movement by adult coastal cutthroat trout (Oncorhynchus clarki) using radiotelemetry. Fish captured in stream pools containing large woody debris moved less than fish captured in pools lacking large woody debris or other cover. Fish from pools lacking cover commonly moved to habitats with large boulders or brush, particularly during the day. Movements by fish over 1-day periods were strongly influenced by large woody debris or other elements providing cover. Fish initially found in habitats lacking large woody debris, large boulders, or brush cover moved the most extensively, while fish initially found in pools with large woody debris moved the least. Fish did not move extensively in response to a bankfull flood, although some moved to habitat downstream of large woody debris in tributaries or secondary channels. Habitat downstream of woody debris in the main channel was not used during the flood, apparently because of extreme turbulence. Overall, these observations provide additional evidence for the value of habitat complexity to some stream fishes and support previous observations of minimal effects of flooding on adult fish.

Large Woody Debris and Salmonid Habitat in a Small Coastal British Columbia Stream

1992 ◽  
Vol 49 (4) ◽  
pp. 682-693 ◽  
Author(s):  
Kurt D. Fausch ◽  
Thomas G. Northcote
Keyword(s):  
British Columbia ◽  
Standing Crop ◽  
Coho Salmon ◽  
Woody Debris ◽  
Cutthroat Trout ◽  
Large Woody Debris ◽  
Habitat Conditions ◽  
Debris Removal ◽  
Coastal British Columbia ◽  
Complex Habitat

Sections of a small coastal British Columbia stream that had previously been cleaned of large woody debris (LWD) were compared with sections where most debris was left and with others where debris had been relatively undisturbed for at least 40 yr. Three sections where debris had been removed had simple habitat that was less sinuous, wider, and shallower and had less pool volume and overhead cover than four sections with more complex habitat where debris was retained. Habitat in four relatively undisturbed sections was generally similar to complex sections. Most pools in all sections were scour or plunge pools formed by LWD or large roots oriented perpendicular to the flow or angled downstream. Standing crop (kolograms per hectare) and individual weights of age 1 + and older coho salmon (Oncorhynchus kisutch) and cutthroat trout (O. clarki) were significantly greater (P < 0.02) in complex than in simple sections. Biomass of age 1 + and older salmonids was closely related to section pool volume (r2 = 0.92, P = 0.0006). Projections based on this model and average habitat conditions suggest that during 1990 a total of 8.0 kg of salmonid biomass, 5 times the current standing crop, was forgone in the 332-m simple reach due to prior debris removal.

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.

Effects of large woody debris placement on stream channels and benthic macroinvertebrates

1997 ◽  
Vol 54 (4) ◽  
pp. 931-939 ◽  
Author(s):  
R H Hilderbrand ◽  
A D Lemly ◽  
C A Dolloff ◽  
K L Harpster
Keyword(s):  
Woody Debris ◽  
Large Woody Debris ◽  
Stream Channels ◽  
High Gradient ◽  
Restoration Technique ◽  
Randomized Design ◽  
Random Placement ◽  
Proportional Increase ◽  
Stream Pool ◽  
Pool Area

Large woody debris (LWD) was added as an experimental stream restoration technique in two streams in southwest Virginia. Additions were designed to compare human judgement in log placements against a randomized design and an unmanipulated reach, and also to compare effectiveness in a low- and a high-gradient stream. Pool area increased 146% in the systematic placement and 32% in the random placement sections of the low-gradient stream, lending support to the notion that human judgement can be more effective than placing logs at random in low-gradient streams. Conversely, the high-gradient stream changed very little after LWD additions, suggesting that other hydraulic controls such as boulders and bedrock override LWD influences in high-gradient streams. Logs oriented as dams were responsible for all pools created by additions regardless of stream or method of placement. Multiple log combinations created only two pools, while the other seven pools were created by single LWD pieces. Total benthic macroinvertebrate abundance did not change as a result of LWD additions in either stream, but net abundances of Plecoptera, Coleoptera, Trichoptera, and Oligochaeta decreased, while Ephemeroptera increased significantly with the proportional increase in pool area in the low-gradient stream.

Response of Juvenile Coho Salmon and Steelhead to Placement of Large Woody Debris in a Coastal Washington Stream

1997 ◽  
Vol 17 (4) ◽  
pp. 947-963 ◽  
Author(s):  
C. J. Cederholm ◽  
R. E. Bilby ◽  
P. A. Bisson ◽  
T. W. Bumstead ◽  
B. R. Fransen ◽  
...  
Keyword(s):  
Coho Salmon ◽  
Woody Debris ◽  
Large Woody Debris

Stream bed configuration and stability following gabion weir placement to enhance salmonid production in a logged watershed subject to debris torrents

1986 ◽  
Vol 16 (2) ◽  
pp. 197-203 ◽  
Author(s):  
H. D. Klassen ◽  
T. G. Northcote
Keyword(s):  
Coho Salmon ◽  
High Flow ◽  
Steelhead Trout ◽  
Slope Gradient ◽  
Spawning Habitat ◽  
Queen Charlotte Islands ◽  
Organic Debris ◽  
Flow Channels ◽  
The Stability ◽  
Pool Area

Tandem V-shaped gabion weirs for improving spawning habitat for salmon (Oncorhynchus spp.) were installed to replace large organic debris at three sites below the terminus of a debris torrent in Sachs Creek, Queen Charlotte Islands. Stream conditions were compared between gabion and nearby control sites. The stability of added and entrapped gravel at all gabion sites was poor over the first winter and excessive scour threatened the integrity of the upstream steeper (3%) slope gabion site. However, the two gabion sites at a lower (1%) slope successfully stabilized spawning gravel in the 2nd year after installation, probably through a reduction in the local slope gradient and self-armouring of the high flow channels. Higher summer densities of juvenile coho salmon (Oncorhynchuskisutch (Walbaum)) and steelhead trout (Salmogairdneri Richardson) were recorded at the gabion sites (means, 1.2 and 0.33/m2, respectively) compared with the control sites (means, 0.89 and 0.10/m2). Underyearling coho fry were also significantly larger (p < 0.05) at gabion sites (mean, 50 mm) than at control sites (mean, 45 mm). Improved rearing habitat was created for coho juveniles by the gabions, a result of increased pool area and cover.

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