Marine Mortality of Puget Sound Coho Salmon (Oncorhynchus kisutch)

1976 ◽  
Vol 33 (8) ◽  
pp. 1677-1684 ◽  
Author(s):  
Stephen B. Mathews ◽  
Raymond Buckley
Keyword(s):  
Coho Salmon ◽  
Survival Curve ◽  
Puget Sound ◽  
Survival Rates ◽  
Oncorhynchus Kisutch ◽  
High Survival ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Marine Life ◽  
Mortality Model

A model for natural mortality over the 18 mo of marine life of Puget Sound coho salmon (Oncorhynchus kisutch) is proposed, wherein the natural mortality rate M continuously decreases with increasing weight. Weight closely follows an increasing exponential function of marine age. The model is extended to account for ocean troll and sport fishing mortality and applied to data from marking studies of Puget Sound coho. The survival curve for marine life with only natural mortality declines rapidly for early ocean life and is quite flat over the ages fished. Recent high survival rates for hatchery coho released at a larger than normal size could be partially explained by this mortality model, although additional marking experiments are needed to separate the effects upon survival of size at release and time of release. The model applied to hatchery release-size strategy indicates that 70 g/fish might be optimal.

Natural Mortality Rate in Last Winter of Life of Coho Salmon (Oncorhynchus kisutch) Resident in Puget Sound

1974 ◽  
Vol 31 (6) ◽  
pp. 1158-1160 ◽  
Author(s):  
Stephen B. Mathews ◽  
Raymond Buckley
Keyword(s):  
Mortality Rate ◽  
Coho Salmon ◽  
Puget Sound ◽  
Oncorhynchus Kisutch ◽  
Fork Length ◽  
Natural Mortality

The natural mortality rate during a 3.5-mo period of the last year of life of coho salmon (Oncorhynchus kisutch) resident in Puget Sound was estimated to be 48% of the population at the beginning of this period. This estimate was based on recaptures of 29 fish out of 169, averaging 32 cm in fork length, tagged in January and early February, and 20 out of 61 averaging 41 cm tagged in May and early June, 1970.

scholarly journals Multiyear tagging studies incorporating fishing effort data

1998 ◽  
Vol 55 (6) ◽  
pp. 1466-1476 ◽  
Author(s):  
John M Hoenig ◽  
Nicholas J Barrowman ◽  
William S Hearn ◽  
Kenneth H Pollock
Keyword(s):  
Mortality Rate ◽  
Additional Data ◽  
Survival Rates ◽  
Fishing Effort ◽  
Reporting Rate ◽  
Natural Mortality ◽  
Fishing Mortality ◽  
Recovery Rates ◽  
Sampling Survey ◽  
Tag Shedding

The Brownie models for multiyear tagging studies can be used to estimate age- and year-specific annual survival rates and tag recovery rates. The latter are composites of the exploitation rates and rates of tag reporting, tag shedding, and tag-induced mortality. It is possible to estimate the exploitation rates if the other components of the tag recovery rates can be quantified. Instantaneous rates of fishing and natural mortality can be estimated if information is available on the seasonal distribution of fishing effort. The estimated rates are only moderately dependent on the timing of the fishing; consequently, the relative effort data can be crude. Information on the timing of the catch over the course of the year can be used as a substitute for the effort data. Fishing mortality can also be assumed to be proportional to fishing effort over years; consequently, if fishing effort is known then the tag reporting rate, natural mortality rate, and a single catchability coefficient can be estimated (instead of natural mortality and a series of fishing mortalities). Although it is possible in theory to estimate both the tag reporting rate and the natural mortality rate with all of these models, in practice it appears necessary to obtain some additional data relating to tag reporting rate to obtain acceptable results. The additional data can come from a variable reward tagging study, a creel or port sampling survey, or from tagged animals that are secretly added to the fishers' catches.

Influence of parental stock and incubation temperature on the early development of coho salmon (Oncorhynchus kisutch) in British Columbia

1990 ◽  
Vol 68 (2) ◽  
pp. 347-358 ◽  
Author(s):  
C. B. Murray ◽  
T. D. Beacham ◽  
J. D. McPhail
Keyword(s):  
British Columbia ◽  
Coho Salmon ◽  
Incubation Temperature ◽  
Survival Rates ◽  
Oncorhynchus Kisutch ◽  
Queen Charlotte Islands ◽  
Hatching Time ◽  
Parental Stock ◽  
Queen Charlotte Island ◽  
Developmental Characteristics

Coho salmon (Oncorhynchus kisutch) stocks in British Columbia spawning from October to April were surveyed for variation in developmental characteristics at incubation temperatures from 1.5 to 15 °C. There were no trends in embryo or alevin survival rates associated with spawning time or spawning temperature. The highest embryo and alevin survival rates occurred at 4 or 5 °C and complete mortality generally occurred at 14 or 15 °C. Vancouver and Queen Charlotte Island stocks had lower survival rates at 1.5 and 2 °C than did mainland stocks. Time to 50% hatching and 50% emergence varied inversely with incubation temperature. Alevin hatching time for the Pallant Creek stock on the Queen Charlotte Islands was later than for all other stocks. Stocks had different trends in alevin and fry length and weight with respect to incubation temperature. Northern stocks tended to be more efficient than southern stocks at converting yolk to body tissue at 1.5 and 2 °C, as were mainland stocks compared with island stocks.

Influences of Upwelling, Ocean Temperature, and Smolt Abundance on Marine Survival of Coho Salmon (Oncorhynchus kisutch) in the Oregon Production Area

1986 ◽  
Vol 43 (3) ◽  
pp. 527-535 ◽  
Author(s):  
Thomas E. Nickelson
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
High Survival ◽  
Ocean Temperature ◽  
Related Factors ◽  
Public And Private ◽  
Adult Relationships ◽  
Significant Relationships ◽  
Production Area ◽  
Marine Survival

The relationships between the marine survival of hatchery and wild coho salmon (Oncorhynchus kisutch) in the Oregon Production Area and ocean upwelling, ocean temperature, and smolt abundance were investigated. Hatchery coho appear to be more sensitive than wild coho to changes in upwelling-related factors although this difference may be due to errors in the estimates of wild smolts and adults that were used in the analysis. Two levels of upwelling (strong and weak), which are associated with a twofold difference in survival of hatchery coho smolts, were identified. Significant relationships were identified between survival of hatchery smolts and survival of wild smolts that migrated in strong upwelling years and sea-surface temperature during that year. Similar relationships were not as apparent for smolts migrating in weak upwelling years as they were for smolts migrating in strong upwelling years. Each major component of coho production (wild, public hatchery, and private hatchery), when treated separately, as well as public and private hatchery coho combined, exhibited linear smolt-to-adult relationships. Only hatchery plus wild coho that migrated in weak upwelling years and hatchery plus wild coho in all years combined exhibited nonlinear smolt-to-adult relationships. I concluded that these nonlinear relationships were caused by a shift in the stock composition of the Oregon Production Area coho population from predominantly high-survival, wild fish when smolt numbers were low to predominantly low-survival, hatchery fish when smolt numbers were high.

Transferrin Polymorphism in Coho Salmon (Oncorhynchus kisutch)

1970 ◽  
Vol 27 (12) ◽  
pp. 2371-2373 ◽  
Author(s):  
Fred M. Utter ◽  
Warren E. Ames ◽  
Harold O. Hodgins
Keyword(s):  
Coho Salmon ◽  
Puget Sound ◽  
Oncorhynchus Kisutch ◽  
Columbia River ◽  
Single Locus ◽  
Potential Usefulness ◽  
Stock Identification ◽  
Transferrin Polymorphism

Six transferrin phenotypes observed in sera of coho salmon (Oncorhynchus kisutch) were interpreted as a reflection of three alleles — TfA, TfB, and TfC — at a single locus. The distribution of these alleles differed significantly among samples collected from streams entering Puget Sound and tributaries of the Columbia River, suggesting a potential usefulness of this system for stock identification.

Survival, Ocean Growth, and Ocean Distribution of Differentially Timed Releases of Hatchery Coho Salmon (Oncorhynchus kisutch)

1989 ◽  
Vol 46 (7) ◽  
pp. 1216-1226 ◽  
Author(s):  
Stephen B. Mathews ◽  
Yukimasa Ishida
Keyword(s):  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Adult Survivors ◽  
Small Fish ◽  
Large Fish ◽  
Release Date ◽  
Marine Life ◽  
Coos Bay ◽  
The Mean ◽  
Marine Survival

Estimates of growth rates in early ocean life and length frequency distributions at time of release for adult survivors were inferred from scale measurements for lots of coho salmon (Oncorhynchus kisutch) released at several dates from a Columbia River hatchery (Big Creek) and a southern Oregon hatchery (Coos Bay). Analysis of these measurements failed to support either of two literature-suggested hypotheses for the variability of marine survival of hatchery coho by date of release: (1) intraseasonal variability of food supply during early marine life; and (2) intraseasonally improving ability of smaller individuals within release lots to convert to salt water. Marine survival improved substantially with date of release at both hatcheries. However, fish released earliest, which survived relatively poorly, grew as fast in early marine life as fish released later, which survived better. Thus, poor survival of the early released fish did not appear related to lack of food at early ocean life. For the Big Creek hatchery, no significant differences were seen between the mean lengths at date of release and the mean release-date lengths of adult survivors back calculated from their scales, for lots released on May 5, June 3, and July 2. Apparently, small and large fish of each lot survived with equal probability. For the Coos Bay hatchery, the mean release-date lengths of adult survivors were significantly larger than the mean lengths of all fish released, for each of six lots released between early June and late July. Thus, large fish apparently survived better than small ones within each of these six lots. But there was no seasonal trend in survivability of small fish relative to large ones, contrary to hypothesis (2)

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.

scholarly journals The role of coastal ocean variation in spatial and temporal patterns in survival and size of coho salmon (Oncorhynchus kisutch)

2001 ◽  
Vol 58 (10) ◽  
pp. 2021-2036 ◽  
Author(s):  
Alistair J Hobday ◽  
George W Boehlert
Keyword(s):  
Mixed Layer ◽  
Environmental Conditions ◽  
Coho Salmon ◽  
Mixed Layer Depth ◽  
Puget Sound ◽  
Oncorhynchus Kisutch ◽  
Vancouver Island ◽  
Coastal Ocean ◽  
Release Time ◽  
Adult Size

Interannual and decadal variability in ocean survival of salmon are well known, but the mechanisms through which environmental variability exerts its effects are poorly understood. Data on hatchery-reared coho salmon (Oncorhynchus kisutch) from individual releases (1973–1998) along the species' entire North American range were analyzed to provide information on survival and size. Three geographic regions (north of Vancouver Island, Puget Sound and Strait of Georgia, and the outer coast south of the tip of Vancouver Island) showed coherent trends in survival and size of returning fish. Within each region, multivariate nonlinear models were used to relate coho survival and final size to spatially and temporally tailored environmental variables at time periods of release, jack return, and adult return. The most important environmental variable, as indicated by the highest amount of variance explained, was a calculated proxy for mixed-layer depth, followed by sea level. In all regions, survival and adult size were most influenced by environmental conditions at the release time. A shallow mixed layer was associated with increased survival and decreased size in all regions. Improved understanding of the relationship between environmental conditions and size and survival of coho salmon provides insight into production patterns in the coastal ocean.

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