Male competition and breeding success in captively reared and wild coho salmon (Oncorhynchus kisutch)

2001 ◽  
Vol 58 (4) ◽  
pp. 804-810 ◽  
Author(s):  
B A Berejikian ◽  
E P Tezak ◽  
L Park ◽  
E LaHood ◽  
S L Schroder ◽  
...  
Keyword(s):  
Pacific Northwest ◽  
Coho Salmon ◽  
Stream Channels ◽  
Artificial Rearing ◽  
Body Coloration ◽  
The Pacific ◽  
Direct Competition ◽  
Dna Genotyping ◽  
Satellite Males ◽  
Laboratory Stream

In the Pacific Northwest, releasing captively reared adult salmon (Oncorhynchus spp.) for natural spawning is an evolving strategy for the recovery of imperiled populations. However, the ability of captively reared fish to spawn naturally may be compromised by their artificial rearing environments. In this study, wild coho salmon (O. kisutch) males outcompeted captively reared males and controlled access to spawning females in 11 of 14 paired trials in laboratory stream channels. In two cases where satellite males were observed participating in spawning, DNA genotyping results determined that they did not sire any of the progeny. When spawning occurred at night and was not observed, DNA results confirmed behavior-based determinations of dominance made before dark. Dominance was established soon after the males were introduced into a common arena containing a sexually active female. We hypothesize that decisions by subordinate males to avoid direct competition may have minimized conflict. The competitive inferiority of captively reared coho salmon in this and a previous study probably reflects deficiencies in rearing environments, which fail to produce appropriate body coloration and body shape and perhaps alter natural behavioral development.

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.

Decadal Climate Variation and Coho Salmon Catch

2003 ◽  
Author(s):  
David Greenland
Keyword(s):  
Pacific Northwest ◽  
Coho Salmon ◽  
Juvenile Fish ◽  
Early Summer ◽  
Air Temperatures ◽  
Ecological Changes ◽  
The Pacific ◽  
Freshwater Stream ◽  
Long Term Ecological Research ◽  
Decadal Climate

When temporally smoothed data are used for the period 1925 to 1985 there is a close inverse statistical relationship acting at an interdecadal timescale between the Pacific Northwest (PNW) air temperatures and Coho salmon catch off the coast of Washington and Oregon. This relationship is now well known, although not fully explained, but at the time of its discovery in 1994 it was part of advances being made by several research groups on interdecadal-scale climate/ecological changes in the PNW (Greenland 1995). The discovery and later, related findings may be usefully examined within the context of the framework questions of this book (see chapter 1) because it provides a very interesting example of climate variability and ecosystem response found, in part, by Long-Term Ecological Research (LTER) investigators. The logical progression for this chapter is first to review a little of the relationship between Coho salmon and climate and then to explain how a study at one LTER site led to a finding with regional implications. An update of the findings at interdecadal-scale climate/ecological changes in the PNW is then appropriate, followed by a discussion of the topic with the framework questions of this book. The PNW is defined, for the purposes of this chapter, as the area of Washington and Oregon west of the crest of the Cascade Range. The term decadal is used loosely in this chapter to refer to changes that focus on time periods of about 10 to 30 years in length. Salmon live part of their lives in terrestrial, freshwater environments and part in marine, saltwater environments. The salmon life history starts with fertilized eggs remaining in gravel in freshwater stream beds and hatching after 1–3 months. One to five months later, fry emerge in the spring or summer. Juvenile fish are in freshwater from a few days to 4 years, depending on species and locality. After the juveniles change to smolts, they can migrate to the ocean, usually in spring or early summer, often taking advantage of streamflows driven by snowmelt. The fish spend 1–4 years in the ocean and then return to their freshwater home stream to spawn and die. More specifically, the typical life cycle for Oregon Coho spans 3 years (18 months in freshwater and 18 months in the ocean).

Spatial and temporal distribution of coho salmon carcasses in a stream in the Pacific Northwest, USA

Hydrobiologia ◽  
2005 ◽  
Vol 539 (1) ◽  
pp. 163-166 ◽  
Author(s):  
Noboru Minakawa ◽  
Robert I. Gara
Keyword(s):  
Pacific Northwest ◽  
Coho Salmon ◽  
Temporal Distribution ◽  
Spatial And Temporal Distribution ◽  
The Pacific ◽  
Salmon Carcasses

Spatial and temporal factors affecting survival in coho salmon (Oncorhynchus kisutch) in the Pacific Northwest

1998 ◽  
Vol 55 (9) ◽  
pp. 2067-2077 ◽  
Author(s):  
Claribel Coronado ◽  
Ray Hilborn
Keyword(s):  
British Columbia ◽  
Pacific Northwest ◽  
Coho Salmon ◽  
Survival Rates ◽  
Oncorhynchus Kisutch ◽  
Dominant Factor ◽  
Spatial And Temporal Patterns ◽  
Factors Affecting ◽  
The Pacific ◽  
Ocean Conditions

Survival rates for coho salmon (Oncorhynchus kisutch) were estimated for all coded wire tag release groups in the Pacific Northwest between 1971 and 1990. The spatial and temporal patterns show considerable geographic variation, with most regions south of northern British Columbia showing declining survival since 1983, while northern areas have shown increasing survival during that period. The number of years of operation explained very little of the variation in survival, and many hatcheries showed major increases in survival after several years of operation. Survival of marked wild fish generally showed the same trend as hatchery fish. We conclude that the dominant factor affecting coho salmon survival since the 1970s is ocean conditions and that there are major geographic differences in the pattern of ocean conditions. The decline in survival seen in British Columbia and south over the last decade suggests that a major reduction in exploitation rates is necessary to maintain the populations.

Geographical and host distribution patterns of Parvicapsula minibicornis (Myxozoa) small subunit ribosomal RNA genetic types

Parasitology ◽  
2011 ◽  
Vol 138 (8) ◽  
pp. 969-977 ◽  
Author(s):  
STEPHEN D. ATKINSON ◽  
SIMON R. M. JONES ◽  
ROBERT D. ADLARD ◽  
JERRI L. BARTHOLOMEW
Keyword(s):  
Pacific Northwest ◽  
River Basin ◽  
Ribosomal Rna ◽  
Dna Sequences ◽  
Coho Salmon ◽  
Pink Salmon ◽  
Type Specimen ◽  
Small Subunit ◽  
The Pacific ◽  
Fish Samples

SUMMARYParvicapsula minibicornis is a myxozoan parasite implicated in mortalities of both juvenile and pre-spawning adult salmon in the Pacific Northwest of North America. Disease severity and presentation varies between salmon species and geographical localities. To better characterize population structure of the parasite, we sought genetic markers in the P. minibicornis ribosomal RNA gene. We compared samples from California with the type specimen from British Columbia, identified sequence variations, and then sequenced 197 samples from fish, river water and the parasite's polychaete worm host. Although DNA sequences of the parasite were >98·9% similar, there was enough variation to define 15 genotypes. All genotypes were detected in fish samples, although not in all species. A single genotype only was found in sockeye and pink salmon in the Fraser River Basin, but was not detected in sockeye from the adjacent Columbia River Basin. All coho salmon, irrespective of river basin, were infected with a unique mix of 2 genotypes. These data indicated that the P. minibicornis population exhibited strong signals of structuring by both geography and salmonid host species. Particular genotypes may correlate with disease differences seen in salmon populations in the Pacific Northwest.

Elevated Streamflows Increase Dam Passage by Juvenile Coho Salmon during Winter: Implications of Climate Change in the Pacific Northwest

2012 ◽  
Vol 32 (6) ◽  
pp. 1070-1079 ◽  
Author(s):  
Tobias J. Kock ◽  
Theresa L. Liedtke ◽  
Dennis W. Rondorf ◽  
John D. Serl ◽  
Mike Kohn ◽  
...  
Keyword(s):  
Climate Change ◽  
Pacific Northwest ◽  
Coho Salmon ◽  
The Pacific

Juvenile salmonid (Oncorhynchus spp.) use of constructed and natural side channels in Pacific Northwest rivers

2005 ◽  
Vol 62 (12) ◽  
pp. 2811-2821 ◽  
Author(s):  
Sarah A Morley ◽  
Patricia S Garcia ◽  
Todd R Bennett ◽  
Philip Roni
Keyword(s):  
Pacific Northwest ◽  
Life Histories ◽  
Coho Salmon ◽  
Habitat Diversity ◽  
Physical Habitat ◽  
Side Channels ◽  
The Pacific ◽  
Western Washington ◽  
Critical Components ◽  
Minimum Daily Temperature

Off-channel habitats, critical components in the life histories of Pacific salmonids (Oncorhynchus spp.), have become increasingly rare in human-modified floodplains. The construction of groundwater-fed side channels is one approach that has been used in the Pacific Northwest to recreate off-channel habitats. We evaluated the effectiveness of this technique by comparing 11 constructed side channels with paired reference sites (naturally occurring channels fed by mixed groundwater and surface water) in western Washington. While total salmonid densities were not significantly different between channel types, coho salmon (Oncorhynchus kisutch) densities were higher in constructed channels and trout densities were higher in reference channels during the winter. Constructed channels were deeper than reference channels and warmer in the winter and cooler in the summer but had lower physical habitat diversity, wood density, and canopy coverage. We did not detect significant differences in water chemistry or invertebrate parameters between channel types. Summer coho density was inversely correlated with minimum daily temperature and with total nitrogen and total phosphorous concentrations. Relative to other stream habitats, both constructed and reference channels supported high densities of juvenile coho salmon during the summer and winter.

Millennial-scale decline in coho salmon abundance since the middle Holocene in a coastal Oregon watershed, USA

2018 ◽  
Vol 89 (2) ◽  
pp. 432-445
Author(s):  
Daniel G. Gavin ◽  
Jennifer E. Kusler ◽  
Bruce P. Finney
Keyword(s):  
Pacific Northwest ◽  
Ocean Circulation ◽  
Nutrient Loading ◽  
Coho Salmon ◽  
Decadal Variation ◽  
Middle Holocene ◽  
The Pacific ◽  
Bulk Organic Matter ◽  
Natural Barrier ◽  
Millennial Scale

ABSTRACTThe population size of anadromous salmon in the Pacific Northwest is strongly influenced by decadal variation in watershed and oceanographic conditions and therefore should also be influenced by larger magnitude millennial-scale variations in these conditions. We studied δ15N of bulk organic matter in lake sediment from Woahink Lake, Oregon, as a proxy of marine-derived nutrients (MDN) from spawning coho salmon. We compared this site to a control lake with a natural barrier to salmon migration. From 7.5 to 5.4 ka, a dune was emplaced, breached, and emplaced again, forming Woahink Lake in a former estuary. δ15N decreased steadily since 5.4 ka at Woahink but not at the control lake. δ15N reached a minimum just prior to anthropogenic nutrient loading, which caused an increase in δ15N, thus precluding a comparison with the historical decline in salmon abundance. A mixing model of lake-water nitrate, developed to explore alternate scenarios for the observed range of δ15N, could not explain these results without invoking MDN input from at least several hundred salmon annually. Our results show a previously unreported pattern of a millennial-scale decline in salmon that has plausible linkages to parallel changes in ocean circulation and productivity.

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