Declines of Juvenile Coastal Cutthroat Trout and Coho Salmon over Fifteen Years in a Salmon-Bearing Stream in the Salish Sea

2021 ◽  
Vol 81 (4) ◽  
Author(s):  
Anne-Marie Flores ◽  
Morgan M. Davies ◽  
Katrina Kushneryk ◽  
Pippi T.E.S. Lawn ◽  
Sibylla Helms ◽  
...  
Keyword(s):  
Coho Salmon ◽  
Cutthroat Trout ◽  
Salish Sea ◽  
Coastal Cutthroat Trout

scholarly journals Evaluating Coexistence of Fish Species with Coastal Cutthroat Trout in Low Order Streams of Western Oregon and Washington, USA

Fishes ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 4
Author(s):  
Kyle D. Martens ◽  
Jason Dunham
Keyword(s):  
Pacific Northwest ◽  
Species Interactions ◽  
Coho Salmon ◽  
Cutthroat Trout ◽  
Single Species ◽  
The Pacific ◽  
Small Streams ◽  
Coastal Cutthroat Trout ◽  
Multiple Species ◽  
Low Order

When multiple species of fish coexist there are a host of potential ways through which they may interact, yet there is often a strong focus on studies of single species without considering these interactions. For example, many studies of forestry–stream interactions in the Pacific Northwest have focused solely on the most prevalent species: Coastal cutthroat trout. To examine the potential for interactions of other fishes with coastal cutthroat trout, we conducted an analysis of 281 sites in low order streams located on Washington’s Olympic Peninsula and along the central Oregon coast. Coastal cutthroat trout and juvenile coho salmon were the most commonly found salmonid species within these streams and exhibited positive associations with each other for both presence and density. Steelhead were negatively associated with the presence of coastal cutthroat trout as well as with coho salmon and sculpins (Cottidae). Coastal cutthroat trout most frequently shared streams with juvenile coho salmon. For densities of these co-occurring species, associations between these two species were relatively weak compared to the strong influences of physical stream conditions (size and gradient), suggesting that physical conditions may have more of an influence on density than species interactions. Collectively, our analysis, along with a review of findings from prior field and laboratory studies, suggests that the net effect of interactions between coastal cutthroat trout and coho salmon do not appear to inhibit their presence or densities in small streams along the Pacific Northwest.

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.

Effects of an increase in large wood on abundance and survival of juvenile salmonids (Oncorhynchus spp.) in an Oregon coastal stream

2005 ◽  
Vol 62 (2) ◽  
pp. 412-424 ◽  
Author(s):  
Steven L Johnson ◽  
Jeffrey D Rodgers ◽  
Mario F Solazzi ◽  
Thomas E Nickelson
Keyword(s):  
Habitat Restoration ◽  
Coho Salmon ◽  
Cutthroat Trout ◽  
Time Frame ◽  
Oncorhynchus Clarki ◽  
Large Wood ◽  
Winter Storm ◽  
Oncorhynchus Clarki Clarki ◽  
Coastal Cutthroat Trout ◽  
Reference Stream

We examined the effect of an increase in large wood on the summer population size, smolt abundance, and freshwater survival of steelhead (Oncorhynchus mykiss), coastal cutthroat trout (Oncorhynchus clarki clarki), and coho salmon (Oncorhynchus kisutch). We examined these parameters for five brood years prior to the addition of wood and five brood years after in Tenmile Creek, a direct ocean tributary on the Oregon coast. Over the same time frame, a nearby reference stream, Cummins Creek, was also sampled for the same parameters. The input of large wood into Tenmile Creek resulted from a planned habitat restoration project in 1996 and an unplanned addition of wood from a winter storm the same year. Steelhead smolt abundance, steelhead freshwater survival, and coho salmon freshwater survival increased in Tenmile Creek after the input of large wood. Steelhead age-0+ summer populations and steelhead smolt populations increased in the reference stream, although steelhead freshwater survival did not. Coho salmon populations remained unchanged in the reference stream. Our results illustrate the potential shortcomings of the before-after-control-impact study design under field conditions and the potential for misinterpreting results had we employed a more modest sampling plan.

Some Morphological Differences Between the Subspecies of Cutthroat Trout, Salmo clarkii clarkii and Salmo clarkii lewisi, in British Columbia

1959 ◽  
Vol 16 (6) ◽  
pp. 903-922 ◽  
Author(s):  
S. U. Qadri
Keyword(s):  
British Columbia ◽  
Lateral Line ◽  
Cutthroat Trout ◽  
Complete Separation ◽  
The Body ◽  
Natural Distribution ◽  
Spot Number ◽  
Coastal Cutthroat Trout ◽  
Morphological Differences ◽  
Coastal British Columbia

Coastal cutthroat trout, S. c. clarkii Richardson, occupy most lakes and streams of coastal British Columbia, including the adjacent islands. Yellowstone cutthroat, S. c. lewisi (Girard), occupy southeastern British Columbia; their range is separated from that of the coastal subspecies by a zone lacking cutthroat trout. A map showing all natural distribution records in the province is presented. From 60 to 146 specimens were examined for distinguishing characters. Spots below the lateral line are more numerous towards the anterior end in S. c. clarkii, but more numerous towards the posterior end in S. c. lewisi. A plot of spot number in selected areas of the body provides almost complete separation of individuals of the two subspecies. Significant differences also occur in certain scale counts and in body and peduncle depth, although these characters overlap considerably between the subspecies. No difference was found in vertebral count.

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