Effectiveness of Selected Stream Improvement Techniques to Create Suitable Summer and Winter Rearing Habitat for Juvenile Coho Salmon (Oncorhynchus kisutch) in Oregon Coastal Streams

1992 ◽  
Vol 49 (4) ◽  
pp. 790-794 ◽  
Author(s):  
Thomas E. Nickelson ◽  
Mario F. Solazzi ◽  
Steven L. Johnson ◽  
Jeffrey D. Rodgers
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Natural Habitats ◽  
Winter Habitat ◽  
Stream Width ◽  
Coastal Streams

We examined the use of constructed pools by juvenile coho salmon (Oncorhynchus kisutch) during summer and winter. Log, gabion, and rock structures placed across the full stream width provided good summer habitat but poor winter habitat for juvenile coho salmon. Rearing densities in constructed habitats during summer and winter were generally similar to those in natural habitats of the same type, except that constructed dammed pools supported lower densities during winter than natural dammed pools. The addition of brush bundles to pools created by full-stream-width structures increased the density of juvenile coho salmon in dammed pools during winter, but not in plunge pools. We concluded that the development of off-channel habitat has the greatest potential to increase production of wild coho salmon smolts in Oregon coastal streams.

Seasonal Changes in Habitat Use by Juvenile Coho Salmon (Oncorhynchus kisutch) in Oregon Coastal Streams

1992 ◽  
Vol 49 (4) ◽  
pp. 783-789 ◽  
Author(s):  
Thomas E. Nickelson ◽  
Jeffrey D. Rodgers ◽  
Steven L. Johnson ◽  
Mario F. Solazzi
Keyword(s):  
Habitat Use ◽  
Seasonal Changes ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Beaver Pond ◽  
Winter Habitat ◽  
Oregon Coast ◽  
Beaver Ponds ◽  
Salmon Fry ◽  
Coastal Streams

Habitat use by juvenile coho salmon (Oncorhynchus kisutch) during spring, summer, and winter was examined in Oregon coastal streams. Coho salmon fry were most abundant in backwater pools during spring. During summer, juvenile coho salmon were more abundant in pools of all types than they were in glides or riffles. During winter, juvenile coho salmon were most abundant in alcoves and beaver ponds. Because of the apparent strong preference for alcove and beaver pond habitat during winter and the rarity of that habitat in coastal streams, we concluded that if spawning escapement is adequate, the production of wild coho salmon smolts in most coho salmon spawning streams on the Oregon Coast is probably limited by the availability of adequate winter habitat.

Winter Distribution of Juvenile Coho Salmon (Oncorhynchus kisutch) Before and After Logging in Carnation Creek, British Columbia, and Some Implications for Overwinter Survival

1983 ◽  
Vol 40 (4) ◽  
pp. 452-461 ◽  
Author(s):  
P. J. Tschaplinski ◽  
G. F. Hartman
Keyword(s):  
Survival Rate ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Habitat Characteristics ◽  
Main Stream ◽  
Low Velocity ◽  
Tree Roots ◽  
Apparent Survival ◽  
Winter Habitat ◽  
Clear Cut

Numbers of juvenile coho salmon (Oncorhynchus kisutch) in streams are reduced substantially in winter compared to those that occur in summer. Most of this reduction occurs early in autumn with the onset of the first seasonal freshets. Stream sections containing adequate winter habitat in the form of deep pools, log jams, and undercut banks with tree roots and debris lost fewer fish during freshets and maintained higher numbers of coho in winter than sections without these habitat characteristics. These features provide shelter and reduce stream velocities. Microhabitats occupied by coho juveniles in winter after logging were unchanged from those described before logging — all microhabitats were characterized by low water velocities (≤ 0.3 m/s). Up to 48% of the coho population inhabiting stream sections with adequate shelter remained there by midwinter (Jan. 3). This percentage was typical of stream sections where at least some trees remained after logging. Streamside trees stabilized the banks and prevented their collapse. In contrast, two of three study sections that had been clear-cut logged had unstable banks which collapsed during winter freshets. Almost no coho remained in these sections in winter. Many coho emigrate from the main stream to seek the shelter of low-velocity tributaries and valley sloughs concurrent with the decline of coho populations in Carnation Creek during autumn and early winter. This seasonal shift in distribution reverses in the spring when large numbers of coho reenter the main stream. Fish overwintering in these sites have a high apparent survival rate. Before logging a 4-yr mean of 169 ± 44 coho entered one tributary (a slough called 750-m site) in autumn. Of these numbers entering, 72.2% came out in spring. During and after logging, an annual mean of 288 coho entered the same site. The apparent survival rate during and after logging was 67.4%, essentially unchanged from the prelogging value. Logging has neither reduced the numbers of coho juveniles that enter such sites in autumn to overwinter, nor reduced the numbers leaving these sites to reenter Carnation Creek in spring.

Variation in Body Morphology Among British Columbia Populations of Coho Salmon, Oncorhynchus kisutch

1985 ◽  
Vol 42 (12) ◽  
pp. 2020-2028 ◽  
Author(s):  
Eric B. Taylor ◽  
J. D. McPhail
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Function Analysis ◽  
Oncorhynchus Kisutch ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Coastal Streams ◽  
Morphological Differences ◽  
Median Fins ◽  
Coastal British Columbia

Ten populations of juvenile coho salmon, Oncorhynchus kisutch, from streams tributary to the upper Fraser River, the lower Fraser River, and the Strait of Georgia region were morphologically compared. Juveniles from coastal streams (Fraser River below Hell's Gate and the Strait of Georgia) were more robust (deeper bodies and caudal peduncles, shorter heads, and larger median fins) than interior Juveniles. Discriminant function analysis indicated that juvenile coho could be identified as to river of origin with 71% accuracy. Juvenile coho from coastal streams were less successfully classified as to stream of origin; however, juveniles could be successfully identified as either coastal or interior with 93% accuracy. Juvenile coho from north coastal British Columbia, Alaska, and the upper Columbia system also fitted this coastal and interior grouping. This suggests that a coastwide coastal–interior dichotomy in juvenile body form exists. Three populations (one interior and two coastal) were studied in more detail. In these populations the coastal versus interior morphology was consistent over successive years, and was also displayed in individuals reared from eggs in the laboratory. Adult coho salmon also showed some of the coastal–interior morphological differences exhibited by juveniles. We concluded that the morphological differences between coastal and interior coho salmon are at least partially inherited.

Influence of Cover Complexity and Current Velocity on Winter Habitat Use by Juvenile Coho Salmon (Oncorhynchus kisutch)

1989 ◽  
Vol 46 (9) ◽  
pp. 1551-1557 ◽  
Author(s):  
Thomas E. McMahon ◽  
Gordon F. Hartman
Keyword(s):  
Habitat Use ◽  
Management Practices ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Structural Complexity ◽  
Rapid Decline ◽  
Stream Channels ◽  
Low Velocity ◽  
Winter Habitat ◽  
Wood Debris

Winter habitat use by juvenile coho salmon (Oncorhynchus kisutch) varied with cover type and flow level in outdoor stream channels. Cover utilization and the number of fish remaining in stream channels increased significantly as cover complexity increased. Most fish emigrated during a simulated freshet unless the most complex cover (low velocity, shade, and wood debris combined) was available. At both high and low flows, emigration occurred primarily during the rapid decline in light levels at twilight. Most coho formed aggregations beneath cover, exhibiting feeding and aggression at temperatures as low as 2.5 °C. We conclude that (1) social interactions, in concert with habitat features, influence the abundance of coho salmon within specific stream habitats in winter, and (2) structural complexity of wood debris is an important consideration for management practices designed to protect or enhance winter habitat for this species.

Use of Hatchery Coho Salmon (Oncorhynchus kisutch) Presmolts to Rebuild Wild Populations in Oregon Coastal Streams

1986 ◽  
Vol 43 (12) ◽  
pp. 2443-2449 ◽  
Author(s):  
Thomas E. Nickelson ◽  
Mario F. Solazzi ◽  
Steven L. Johnson
Keyword(s):  
Surface Area ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Early Time ◽  
Wild Populations ◽  
Pool Surface ◽  
Coastal Streams

We evaluated the effectiveness of using hatchery coho salmon (Oncorhynchus kisutch) presmolts to rebuild wild populations in Oregon coastal streams. Juvenile and adult populations were monitored in 15 stocked and 15 unstocked streams from summer 1980 until summer 1985. During the summers following the planting of presmolts, the number of juveniles per square metre of pool surface area was higher in the stocked streams than in the unstocked streams. However, wild juveniles were significantly less abundant in the stocked streams during the 2 yr when density of wild juveniles was estimated separately from hatchery juveniles. Adult returns to the stocked streams were not significantly different from adult returns to the unstocked streams, but returns tended to be earlier in the stocked streams than in the unstocked streams. Despite similar numbers of adults per kilometre in the stocked streams and unstocked streams in the years the presmolts returned to spawn, the resulting densities of juveniles in the stocked streams were significantly lower than the densities of juveniles in the unstocked streams. We concluded that the early time of spawning of the hatchery coho salmon was largely responsible for their failure to rebuild the populations in the streams stocked with presmolts.

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.

Vertical Distribution of Sediment and Organic Debris in Coho Salmon (Oncorhynchus kisutch) Redds in Three Small Oregon Streams

1988 ◽  
Vol 45 (4) ◽  
pp. 742-747 ◽  
Author(s):  
Neil H. Ringler ◽  
James D. Hall
Keyword(s):  
Vertical Distribution ◽  
Coho Salmon ◽  
Particle Diameter ◽  
Oncorhynchus Kisutch ◽  
Organic Content ◽  
Sediment Particle ◽  
Core Samples ◽  
Organic Debris ◽  
Coastal Streams ◽  
Sediment Layers

Vertical distribution of sediment (particle diameter <3.33 mm) and organic debris was studied in coho salmon (Oncorhynchus kisutch) redds in three Oregon coastal streams subjected to different degrees of logging. Gravel composition in frozen cores varied significantly among redds in both logged streams. Sediment content in redds appeared to decrease with depth in the logged streams, but differences in gravel composition among streams obscured differences among depths. Sediment layers of variable thickness were visible in several core samples. In one logged stream, redds contained an average of 25% less sediment than redds used 1 yr earlier. Organic content of the gravel represented <2.8% of the core samples by weight and was directly related to the quantity of sediment in the streambed. The pattern of vertical distribution of organic debris in the clearcut stream (most abundant near the surface) differed significantly from that in the other two streams. Patterns of distribution and variability in gravel composition were consistent with post-logging changes in gravel permeability and survival to emergence of coho salmon.

Population Characteristics of Juvenile Coho Salmon (Oncorhynchus kisutch) Overwintering in Riverine Ponds

1982 ◽  
Vol 39 (9) ◽  
pp. 1303-1307 ◽  
Author(s):  
N. P. Peterson
Keyword(s):  
Overall Survival ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Early Spring ◽  
Population Characteristics ◽  
Winter Habitat ◽  
Chironomid Larvae ◽  
Fish Weight ◽  
Survival And Growth

Survival and growth from immigration to smolt outmigration differed substantially between pond populations of juvenile coho salmon (Oncorhynchus kisutch). In Pond 1 (the deeper, less-productive pond) overall survival was 78% but average fish weight increased only 49%, whereas in Pond 2 (the shallow, more-productive pond) survival was only 28% but average fish weight increased 94%. Diet of resident coho in the early spring was characterized by chironomid larvae and newly emerged adults in Ponds 1 and 2, respectively. Manipulation of pond morphometry may have potential for enhancing coho stocks.Key words: coho, pond, winter habitat, survival, growth, diet

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