Factors affecting the abundance of fall Chinook salmon in the COlumbia river

442 Pages·2014·12.19 MB·English

AN ABSTRACT OF THE THESIS OF
Jack M. Van Hyning for the Ph. D. in Fisheries
(Name) (Degree) (Major)
in
Date thesis is presented '' \cxi t8 (C+(
Title FACTORS AFFECTING THE ABUNDANCE OF FALL CHINOOK SALMON IN
THE COLUMBIA RIVER
Abstract approved
(Major professor)
A study of the population ecology of Columbia River fall chi-
nook salmon, Oncorhynchus tshawytscha (Walbaum), was made in an attempt
to determine the cause of a serious decline in this run which occurred
in the early 1950's. Fluctuations in abundance of major salmon runs
of the North Pacific were examined to detect any coastwide. pattern.
Only chinook salmon in Cook Inlet, Alaska, and chum salmon from
Oregon to southwestern Alaska showed a similar trend. The following
life history stages broken down into pre- and post -decline years
were examined: (1) marine life including distribution and migration,
growth and maturity, survival rate, oceanography, and commercial
and sport fisheries; (2) upstream migration including river fish-
eries, gear selectivity, size and age composition of the run, es-
capement, and influence of dams, diseases, and water quality; (3)
reproduction and incubation including spawning areas and spawning
and incubation conditions; and (4) downstream migration which in-
cluded predation, dams; and reservoirs, diseases, flow, turbidity and
temperature, and estuary life. Salient points of the analysis were:
(1) a change in the maturity and survival pattern based on tagged
and fin -clipped fish recovered before and after 1950; (2) a signifi-
cant negative correlation between sea -water temperature during a
year class' first year at sea and subsequent survival; (3) a large
increase in the ocean fisheries coincident with the decline in the
run; (4) catch -effort statistics of the ocean fishery show a near
classic example of the effect of overexploitation; (5) estimates of
the contribution of Columbia River chinook to the ocean fisheries
based on tag recoveries could be underestimates rather than over-
estimates; (6) a significant inverse correlation between estimated
ocean catch of Columbia River fall chinook and numbers entering the
river; (7) size and age composition of the ocean and river catches
decreased coincident with the decline in the run; (8) the gill -net
fishery shows little size selectivity by age, size, or sex in the
dominant group; (9) fluctuations in abundance of hatchery stocks
are related to differences in survival between fingerling and adult;
(10) hatchery, lower river, and upriver populations fluctuate in
abundance in much the same pattern; (11) optimum escapement is be-
tween 90,000 and 100,000 adults, a value that was exceeded during
most years; (12) a highly significant negative correlation between
numbers of spawners and return per spawner; (13) most of the early
dams had no direct effect on fall chinook and the decline in pro-
ductivity occurred when river conditions were relatively stable;
(14) temperatures at time of migration and spawning for fall
chinook have not increased enough to be a serious mortality factor;
(15) little relationship between flow, turbidity, and temperature at
time of downstream migration and subsequent return was evident ex-
cept that high temperatures and high flows (and turbidities) tended
to produce poorer runs during certain time periods; and (16) predation
and delay of smolts in reservoirs are largely unknown factors, but cir-
cumstantial evidence suggests that they were not important in regula-
ting fall chinook numbers during the period of the study.
Finally, variables that appeared to bear some relationship to
fluctuations in abundance of fall chinook were submitted to multiple
regression analysis. For the predecline period (1938 -46 brood years),
sea -water temperature and ocean troll fishing effort were significant
variables (R2 = 0.74). For post decline years (l947 -59 broods), troll
had the most influence on total return with ocean temperature and es-
capement having lesser effects. For the combined years, troll in-
tensity and ocean temperature were the significant variables (R2 =
0.572). Entering interaction of river flow at downstream migration
with the other variables brought R2 to 0.754 which means that 75% of
the variability in the returning run could be accounted for by these
three factors. Return per spawner was so heavily influenced by
numbers of spawners that the other factors assumed negligible im-
portance. Equations were derived that predicted the returning run
in close agreement with the actual run size. Substituting a low
and constant troll fishing effort in the equation resulted in the
predicted run maintaining the average predecline level.
The increase in ocean fishing was the main contributor to
the decline of the Columbia River fall chinook run as shown by
correlation, by analogy, and by the process of elimination. To demon-
strate why other chinook runs have not shown similar declines, it was
shown that due to several unique features in Columbia River fall
chinook life history they are exposed to much more ocean fishing than
other populations. It was emphasized that these conclusions should
not be extrapolated to the future or to other species or runs of
salmon.
FACTORS AFFECTING THE ABUNDANCE OF FALL CHINOOK SALMON
IN THE COLUMBIA RIVER
by
JACK MATTSON VAN HYNING
A THESIS
submitted to
OREGON STATE UNIVERSITY
in partial fulfillment of
the requirements for the
degree of
DOCTOR OF PHILOSOPHY
March 1968
APPROVED:
Professor of Fisheries
In Charge of Major
AHead o DIepartmenMt of FisOheries aMnd WildliMfe
Dean of Graduate School
Date thesis is presented j\WV-k-V q(1
Typed by Shirley Arnett and Janice Jennings
ACKNOWLEDGMENTS
Many people unknowingly contributed to the development of this
thesis by faithfully collecting data over a period of many years.
Although too numerous to individually mention, the study would not
have been possible without the backlog of information they collected.
I particularly appreciate the cooperation of Messrs. Henry Wendler and
Donald Kauffman of the Washington Department of Fisheries for making
available unpublished reports and data from their department and re-
viewing the manuscript. Likewise, Messrs. Arthur L. Oakley and
Robert E. Loeffel of the Fish Commission of Oregon were most helpful
in supplying material from their files. I am greatly indebted to
Messrs. Earl F. Pulford and Charles O. Junge of the Fish Commission of
Oregon for advice and guidance on the statistical analysis. Drs. Carl
Bond and Charles E. Warren of Oregon State University rendered valuable
assistance during preparation and review of the dissertation.
Dr. Frederick C. Cleaver reviewed the manuscript, and I appreciate his
penetrating comments. I appreciate the early aid and encouragement of
Dr. Donald W. Chapman and the patience and assistance of Dr. Thomas E.
Kruse and Mr. Robert W. Schoning. Mr. Anthony Netboy of Portland State
College read the manuscript and offered editorial comments and the
assistance of Mrs. Winona Richey, Fish Commission Librarian, was in-
valuable.
This study was largely financed by monies received from the sale
of salmon -steelhead tags (punch cards) required for persons angling for
anadromous fish in Oregon. These funds are to be used for salmon and
steelhead research and management projects.
TABLE OF CONTENTS
Page
INTRODUCTION................... ....0.0.........00.00.0.00....0 1
LIFE HISTORY AND RACIAL IDENTIFICATION ...........0000......... 4
Life History of Chinook Salmon 4
Runs and Races of Columbia River Chinook Salmon 9
REVIEW OF POPULATION FLUCTUATIONS IN OTHER SALMON RUNS 17
Chinook Salmon 18
Coho Salmon ................... ...........c 27
Chum Salmon 30
Pink Salmon 000 35
Sockeye Salmon .. 38
.
Summary 42
MARINE LIFE OF CHINOOK SALMON 47
Range and Migration 47
Tagging 47
Marking 83
Growth and Maturity 92
Variation in Survival Rate 103
Tagging Experiments 104
Marking Experiments 116
Hatchery Returns 121
Ecology 125
General Oceanography 125
Oceanography and Salmon Ecology 133
Application to Columbia River Fall Chinook Salmon 135
Ocean Fisheries 142
Commercial Troll Fishery 142
Japanese Fishery 172
Sport Fishery 173
Hooking Mortality 183
Recapitulation of Ocean Fisheries 187
UPSTREAM MIGRATION 203
River Fisheries 203
Commercial Fishery 203
Indian Fishery 219
Sport Fishery 224
Size and Age Composition of the Run 225
Escapement 245
Dam Counts 245
Spawning Ground Counts 259
Hatchery Enumeration 263
TABLE OF CONTENTS (Cont'd)
Page
Gear Selectivity OOOOO OOOOO 271
Optimum Escapement
282
Dams
291
Parasites and Diseases
299
Water Quality. .... OOOOOOOOOOOOOOOOOO ............... OOOOOO . 308
REPRODUCTION AND INCUBATION ..e ...............e......e.....
... 312
Spawning Areas
312
Spawning and Incubation Conditions .......... ......... .....o 318
Time of Spawning and Emergence ......... OOOOOOOOOOOOOOO 0 318
Temperature ............... .................C..........01C 321
Oxygen and Flow. ......... OOOOOOOOOOO ..... OOOOOO OOOOO 326
0
Pollution and Predation ... ..e.e...eeeeeeee000eeoeeeeoeooe 329
STREAM RESIDENCE AND DOWNSTREAM MIGRATION. ............. OOOOOO 331
General
331
Ecological Factors Affecting Survival 335
Predation
335
Parasites and Diseases
338
Dams and Reservoirs
340
Flow, Turbidity, and Temperature 343
Estuary Conditions
347
MULTIPLE REGRESSION AOND RESPO NSE SURFA.C E 0ANA LYSIS............ 351
DISCUSSION....... OOOOOOOOOOOOOOOOOOO O OOOOOOOO 000 OOOOO 371
o..
S UM MA R Y e . . o . . . e e e o e 80e . o e e. o.. o.. e e. 0. e.. 0 0 0 o e. 386
BIBLIOGRAPHY
402
LIST OF TABLES
Table
Page
1. Comparison of early and recent tagging of chinook off
Vancouver Island based on stream and area of recovery. 70
2. Recoveries from chinook tagged off the Queen
Charlotte Islands and southeastern Alaska
76
3. Calculated troll recoveries of Fish Commission of
Oregon marked fall chinook salmon, by area (from
Pulford, 1964)
86
4. Return of chinook salmon tagged in the ocean, by year
of recovery
105
5. Recovery of tagged chinook salmon by size, April -July
1948 -51 and March -June 1960 -61. (Per cent recovered
of number tagged in parenthesis.) 112
6. Hypothetical return of tagged chinook salmon based
on assumed tagging mortality and unreported tags,
1948 -51 and 1960 -61
114
7. Return of marked hatchery- reared fall chinook 117
8. Age composition of samples of troll- caught chinook
salmon
168
9. Age composition of the chinook sport catch at the
mouth of the Columbia River and Westport 180
10. Estimated percentages of Columbia River hatchery fall
chinook in selected catches
195
11. Important regulations on the Columbia River commercial
fishery
214
12. Age at return of marked Columbia River fall chinook,
1938 -43 -brood years (from Holmes, 1952) 227
13. Age composition of the Columbia River fall chinook
gill -net catch by run year (1957 -64) and brood year
(1955 -59)
235
14. Summary of observations on age composition of Columbia
River fall chinook
239