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

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.

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.

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.

Spatial distribution, survival, and growth of sibling groups of juvenile coho salmon (Oncorhynchus kisutch) in an experimental stream channel

1994 ◽  
Vol 72 (12) ◽  
pp. 2119-2123 ◽  
Author(s):  
Thomas P. Quinn ◽  
Andrew H. Dittman ◽  
N. Phil Peterson ◽  
Eric Volk
Keyword(s):  
Spatial Distribution ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Positive Density ◽  
Stream Channel ◽  
Density Dependent ◽  
Intrapopulation Variation ◽  
Survival And Growth ◽  
Dependent Growth ◽  
Sibling Recognition

The spatial distribution, survival, and growth of two full-sibling families of coho salmon (Oncorhynchus kisutch) in an experimental outdoor stream channel were compared between the families and with the performance of one of the families in an allopatric control channel after 75 d of rearing. No difference in survival was observed between families (81.2% overall), but their spatial distributions in the channel differed markedly. One family or the other numerically dominated 5 of 7 riffle-pool habitat units within the sympatric treatment channel. The family that was larger at the beginning of the experiment (0.52 vs. 0.37 g mean mass) was also larger at the end (2.03 vs. 1.58 g). While there was little evidence of density-dependent growth overall, the growth of each family was correlated with the density of siblings in the unit. However, the larger bodied family showed negative density-dependent growth, whereas the smaller bodied family showed positive density-dependent growth. These patterns of distribution and growth may have arisen from sibling recognition or some other proximate mechanism such as assortative distribution based on size or interfamily variation in aggression. Regardless of the mechanism, intrapopulation variation in distribution and growth may lead to considerable variation in fitness among families because these factors affect success in subsequent freshwater and marine life history stages.

Effects of Salinity on the Survival and Growth of Pre-Smolt Coho Salmon (Oncorhynchus kisutch)

1971 ◽  
Vol 28 (3) ◽  
pp. 343-349 ◽  
Author(s):  
Robert G. Otto
Keyword(s):  
Growth Rate ◽  
Food Intake ◽  
Conversion Efficiency ◽  
Salinity Tolerance ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Management Tool ◽  
Food Conversion ◽  
Survival And Growth ◽  
Food Conversion Efficiency

Salinity tolerance of juvenile coho salmon (Oncorhynchus kisutch) increased markedly during the period from approximately [Formula: see text] months after emergence from the gravel to the onset of the smolt transformation, except for a decline in the fall. In January, salinity tolerance ceased to limit dispersal to the sea. The limiting effects of high salinities on survival were less for larger fish than for smaller individuals and were substantially reduced by a period of exposure to dilute salinities. Growth rate, food intake, and gross food conversion efficiency had the highest values at salinities of 5–10 ppt throughout the pre-smolt period. The results are discussed in relation to the feasibility of using saltwater impoundments as a management tool in increasing coho production.

Acute Toxicities of a Polychlorinated Biphenyl (PCB) and DDT Alone and in Combination to Early Life Stages of Coho Salmon (Oncorhynchus kisutch)

1974 ◽  
Vol 31 (9) ◽  
pp. 1543-1547 ◽  
Author(s):  
Mark T. Halter ◽  
Howard E. Johnson
Keyword(s):  
Polychlorinated Biphenyl ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Early Life Stages ◽  
Survival Times ◽  
Aroclor 1254 ◽  
Egg Hatchability ◽  
Survival And Growth ◽  
Mean Time ◽  
Additive Toxicity

Egg hatchability, mean time to hatching, and alevin survival and growth decreased when coho salmon (Oncorhynchus kisutch) eggs and alevins were exposed at 12–14 C to 4.4 μg/liter Aroclor 1254 or higher until 4 wk after hatching, and to 15 μg/liter or more until 2 days before hatching. Premature hatching occurred in all egg groups exposed to the PCB. The median survival times of fry exposed to Aroclor 1254–DDT combinations for two wk were similar to those after exposure to the various concentrations of DDT alone. The more rapid reaction time to DDT is suggested as the basis for lack of additive toxicity.

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