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.

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.

Plasma thyroid hormones during smoltification of yearling and underyearling coho salmon and yearling chinook salmon and steelhead trout

Aquaculture ◽  
1982 ◽  
Vol 28 (1-2) ◽  
pp. 39-48 ◽  
Author(s):  
Walton W. Dickhoff ◽  
Leroy C. Folmar ◽  
James L. Mighell ◽  
Conrad V.W. Mahnken
Keyword(s):  
Thyroid Hormones ◽  
Chinook Salmon ◽  
Coho Salmon ◽  
Steelhead Trout

Spatiotemporal patterns in migration timing of coho salmon (Oncorhynchus kisutch) smolts in North America

2010 ◽  
Vol 67 (8) ◽  
pp. 1316-1334 ◽  
Author(s):  
Brian C. Spence ◽  
James D. Hall
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Columbia River ◽  
Life Transition ◽  
Regional Patterns ◽  
Migration Patterns ◽  
Watershed Characteristics ◽  
Migration Timing ◽  
Queen Charlotte Islands ◽  
Kodiak Island

The timing of ocean entry by salmon smolts is presumed adaptive to maximize survival during this critical life transition. We analyzed the peak timing, duration, and interannual variation in timing of smolt migrations for 53 coho salmon ( Oncorhynchus kisutch ) populations from central California to Kodiak Island, Alaska. The objective was to examine potential influences of both local watershed characteristics and larger-scale processes in the marine environment on smolt migration patterns. Multivariate analyses demonstrated a strong latitudinal gradient in migration patterns with trends toward later, shorter, and more predictable migrations with increasing latitude. Cluster analysis performed on migration descriptors indicated three major population groupings that coincide with major coastal oceanic regions in the northeast Pacific: a northern group from Kodiak Island to the Queen Charlotte Islands, British Columbia, a central group from the Queen Charlotte Islands south to the Columbia River, and a southern group from the Columbia River southward. These regional patterns transcended local variability associated with watershed characteristics and trap location, suggesting that the patterns reflect adaptation to differences in timing and relative predictability of favorable conditions in the marine environments that smolts enter.

Stomach Contents of Salmon and Steelhead Trout in the Northeastern Pacific Ocean

1966 ◽  
Vol 23 (1) ◽  
pp. 85-100 ◽  
Author(s):  
R. J. LeBrasseur
Keyword(s):  
Pacific Ocean ◽  
Chum Salmon ◽  
Coho Salmon ◽  
Pink Salmon ◽  
Stomach Contents ◽  
Northwestern Pacific ◽  
Steelhead Trout ◽  
Fish Size ◽  
Northeastern Pacific

Stomachs of pink, chum, sockeye, and coho salmon and steelhead trout caught during the summer of 1958 in gillnets fished overnight in the northeastern Pacific Ocean contained mainly zooplankton (Limacina, amphipods, copepods, and euphausiids), squid, and fish. Except for sockeye, there were no differences in contents related to fish size or state of maturity. Differences were found between species in the kinds of stomach contents present. The predominant organisms were amphipods and fish in pink salmon, crustaceans in immature sockeye, euphausiids and squid in maturing sockeye, euphausiids, fish, and squid in coho, and fish and squid in steelhead stomachs. The stomach contents of chum salmon were notable in that most of their contents were too well digested to identify. Comparison with the findings of workers in the northwestern Pacific showed no significant differences in the kinds of stomach contents, however, a greater amount of material was present in the stomachs they examined. The contents of stomachs from fish taken in various ocean domains were compared. Greater differences were noted in the stomach contents of fish from different domains than from different species. It is suggested that feeding is associated more with availability rather than with preferences for specific organisms.

The Stability of 3D-Geomat in Different Slope Gradient

2014 ◽  
Vol 580-583 ◽  
pp. 782-786
Author(s):  
Guang Yue Wang ◽  
Jian Peng Zhang ◽  
Yuan Shuai Sun
Keyword(s):  
Water Conservation ◽  
Element Model ◽  
Slope Gradient ◽  
Slope Surface ◽  
Engineering Construction ◽  
Ecological Protection ◽  
New Type ◽  
The Stability ◽  
The Finite Element Model ◽  
Soil And Water

3D-geomat protective slope is a new type of protective slope form which combines the 3D-geocell with the planting grass. Because the complex and dense spatial structure can tie the slope soil and has a reinforced effect on the slope surface, it has the advantage in soil and water conservation and ecological protection, and it gets more and more widely used in the present engineering construction. By using the finite element model, we compare the whole stability in the 3D-geomat slope and unprotective slope under the condition of different slope gradient. And then we get the relative results.

scholarly journals MEMBANGUN MODEL DINAMIS PENANGKARAN POPULASI MALEO (Macrochepalon Maleo) YANG MEMPERTAHANKAN EKSISTENSINYA DARI PREDATOR

2018 ◽  
Vol 15 (2) ◽  
pp. 144-156
Author(s):  
T Gusmawan ◽  
R Ratianingsih ◽  
N Nacong
Keyword(s):  
Critical Point ◽  
Critical Points ◽  
Captive Breeding ◽  
Growth Dynamics ◽  
Growth Cycle ◽  
Extinction Condition ◽  
Spawning Habitat ◽  
Conservation Areas ◽  
Free Zone ◽  
The Stability

Maleo (Macrocephalon maleo) is one of the endangered endemic species of Sulawesi due to diminishing spawning habitat, community exploitation and predators. The dynamic model of maleo population captivity to conserve its existence from predators is a mathematical model that describes the dynamics of maleo population growth cycle (M) with the threat of predators (P). In this study, the population of eggs maleo divided into two groups that are eggs in the free zone (Tb) and eggs in breeding (Tp). The eggs are in the captive breeding will be transfered to the exposure group (E). The model represents the interaction between the predators and populations reflecting maleo in each growth phase. The model has two critical points, namely the critical point 𝑇1 = ( 0,0,0,0, 𝜑 µ2 ) describing maleo extinction condition and critical point 𝑇2 = (𝑀∗ , 𝑇𝑝∗ ,𝐸 ∗ , 𝑇𝑏∗ , 𝑃 ∗ ) which describes the endemic conditions of maleo growth dynamics. The stability analysis shows that the system is unstable at both critical points. It is because the values of the first column in the Routh Hurwitz table changes in sign. Simulations of the endemic conditions showed that the maleo and egg populations in the free zone are decreasing with respect to time even though the exposed maleo still exist. The unstable endemic indicates that the existence of maleo breeding program in conservation areas still need another efforts support.

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