1. sports
2. fishing

STUDIES OF BIG LAGOON
HUMBOLDT COUNTY, CALIFORNIA
1956 - 1958
by
James Joseph
A Thesis
Presented to
The Faculty of Humboldt State College
In Partial Fulfillment
of the Requirements for the Degree
Master of Science
June 1958
Apprονed by the Masters' Thesis Committee
Chairman
Approved for the Graduate Study Committee
ACΚΝΟWLLDGEMENTS
I would like to express gratitude to Dr. Ernest 0. Salo,
chairman of my graduate committee, for his advice and aid in the
planning, execution, and completion of my research project and
thesis. Acknowledgement and thanks are also extended to Dr. George
H. Allen for his aid in the revisions leading to this final copy.
Special acknowledgement for the basic material used in the
geological history of the study area is made to Dr. Harry D.
MacGinitie, Chairman of the Division of Natural Science, Humboldt
State College.
Mr. Stanley D. Elcock and I worked on Big Lagoon jointly
and much of the accumulated data is a result of combined efforts.
Mr. Εlcοck's research was primarily concerned with the fishes of
the lagoon and its tributaries; therefore direct acknowledgement
is given him for the reports included in this paper concerned with
fish populations. Sincere gratitude is expressed for his cooperation in making this thesis possible.
Special thanks and gratitude are extended to Messrs.
William Pogue, Jiro Nishimoto, Richard Nitsos, Pat Tomlinson,
Robert Hughes, Jack Legate, James Adams, and numerous other
students who willingly donated their time in the gathering of
field data used in this report.
To Mrs. Ruth Elliot, Secretary, Department of Natural
Resources, Humboldt State College, special thanks are extended
for her patience and understanding in administrative matters
concomitant with graduate students and school policy.
Thanks are given to The California-Hammond Branch of the
Georgia-Pacific Corporation for permission to carry on research
at their Big Lagoon Camp.
TABLE OF CONTENTS
PAGE
LIST OF TABLES
iv
LIST OF FIGURES
v
INTRODUCTION
1
METHODS, MATERIALS, AND SOURCES OF ERROR
4
VERBAL CONFERENCES
4
METHODS USED IN THE PHYSICAL AND CHEMICAL SURVEY OF BIG LAGOON
4
Mapping
4
Water Sampling
5
Salinity Determinations
5
Dissolved Oxygen Determinations
7
Phosphate Determinations
8
Temperature Determinations
9
Stream Flow Determinations
10
METHODS USED IN THE STUDIES OF FISH POPULATIONS OF BIG LAGOON
10
Gill Netting
10
Seining
10
Creel Censusing
12
Population Estimates in Maple Creek
12
14
RESULTS
GEOLOGICAL HISTORY OF BIG LAGOON
14
Formation of the Lagoon
15
iii
TABLE OF CONTENTS (Continued)
PAGE
Alongshore Currents and the Formation of the Sand Bar
16
Geological Future
18
PHYSICAL DESCRIPTION OF BIG LAGOON AND ITS WATERSHED
18
Big Lagoon Bar
21
Tributaries and Drainage
27
CLIMATOLOGICAL FEATURES
36
Rainfall
36
Wind
36
Fog
39
Temperature
39
CHEMICAL DESCRIPTION OF BIG LAGOON
57
Salinity Patterns
57
Oxygen Patterns
64
Temperature Patterns
76
Mixing
76
PRELIMINARY REPORT ON THE RESIDENT AND INTRODUCED POPULATIONS
OF FISHES
78
Qualitative
78
Quantitative
83
Gill Netting
83
Creel Census
83
Stream Census
83
DISCUSSION AND RECOMMENDATIONS
89
THE ENVIRONMENT OF THE LAGOON
89
POSSIBLE LIMITING FACTORS OF THE LAGOON ENVIRONMENT ON THE
PRODUCTION OF SALMONOIDS
90
iii
TABLE OF CONTENTS (Continued)
PAGE
THE TIMING OF SALMON AND STEELHEAD RUNS AS A POSSIBLE
LIMITING FACTOR
92
CONDITIONS IN THE LAGOON AT THE TIME OF DOWNSTREAM MIGRATION
94
King Salmon
94
Silver Salmon and Steelhead
95
VARIATIONS IN THE ANNUAL CYCLE OF BIG LAGOON AND THE
POSSIBILITY OF PREDICTING WATER CONDITIONS
97
RECOMMENDATIONS CONCERNING A SPILLWAY AND/OR TIDAL GATES
97
SUMMARY
99
LITERATURE CITED AND ADDITIONAL REFERENCES
103
APPENDIX
110
iv
LIST OF TABLES
PAGE
TABLE
1
2.
3
4
5
6
7
8
9
10
Observed Water Temperature and Stream Flow Data frοm Maple
Creek for the Period March 3, 1957 to October 11, 1957
28
Average Hourly Wind Velocity and Prevailing Direction for
Eureka, California
35
Air Temperature Data for the Period 1956-1957 from Prairie
Creek State Park
40
A Check List of Fishes Taken in Big Lagoon from January
1957 to December 1957
79
Gill Netting Data from Big Lagoon, January 29, 1957 to
August 30, 1957
80
Summary of Big Lagoon Creel Census, April 27, 1957 to May
12, 1957
81
Summary of Big Lagoon Creel Census, May 3 and 4, 1958
82
Summary of First and Second Mark-Recovery Program in Maple
Creek, Summer-Fall, 1957
84
Daily Seine Samples of Trout and Salmon from Maple Creek,
April 7-21, 1958
85
Hatchery Plants by Humboldt State College into Maple Creek,
1958
87
V
LIST OF FIGURES
PAGE
FIGURE
1
Map of Big Lagoon Showing Bottom Contours
2
Map of the Maple Creek Drainage Showing Pitcher Creek and
Big Lagoon
3 Map of Humboldt County Lagoons
Cover
11
17
Aerial View of North End of Big Lagoon
19
4a Aerial View of South End of Big Lagoon
20
4
5
Discharge of Big Lagoon Waters After Breaching, Looking South
22
6
Discharge of Big Lagoon Waters After Breaching, Looking West
23
7
Openings of Big Lagoon Bar Showing Intermittent Lagoon Levels
and Monthly Rainfall for the Period October 1956 to January
1958
25
8
Aerial View of Maple Creek Watershed
29
9
Monthly Variation of Streamflow, Air Temperature, Stream
Temperature and Rainfall for the South Fork of Maple Creek
for the Period March to October 1957
30
Stream Temperature and Flow, Tom Creek, October to September
1957
33
Average Monthly Rainfall and Cumulative Rainfall at Big Lagoon
for the Period October 1, 1956 to September 30, 1957,
Compared to a Nine-Year Monthly Average
34
Average Monthly Fog Incidence Compared with the Average Monthly
Temperature for the Eureka Area
37
10
11
12
13 Mean Maximum-Minimum Air Temperatures, Prairie Creek State
Park, 1956-1957
38
14 T-S Diagram Showing Salinity Anomaly at Station C, Big Lagoon
on August 8, 1957
41
15 Salinity-Depth Diagram Showing Salinity Anomaly at Station C,
Big Lagoon on August 8, 1957
41
Distribution of Chlorinity in Vertical Section Across Station
B and C, Big Lagoon, November 15, 1956
42
Distribution of Chlorinity in Vertical Section, Big Lagoon,
November 16, 1956
43
16
17
vi
LIST OF FIGURES (Continued)
PAGE
FIGURE
18
Distribution of Chlorinity in Vertical Section, Big Lagoon
December 31, 1956
44
19
Distribution of Chlorinity, Oxygen and Temperature in Vertical
Section across Stations C and D, Big Lagoon, January 3, 1957 45
20
Distribution of Chlorinity in Vertical Section, Big Lagoon,
February 19, 1957
46
Distribution of Chlorinity in Vertical Section, Big Lagoon,
April 9, 1957
47
Distribution of Chlorinity in Vertical Section Through
Stations A, B, C, and D, Big Lagoon, July 7, 1957
48
Distribution of Chlorinity in Vertical Section Through
Stations A, B, C, and D, Big Lagoon, July 16, 1957
49
Distribution of Chlorinity in Vertical Section, Big Lagoon,
August 7, 1957
50
Distribution of Chlorinity in Vertical Section, Big Lagoon,
August 8, 1957
51
Distribution of Chlorinity in Vertical Section, Big Lagoon,
August 10, 1957
52
Distribution of Chlorinity in Vertical Section, Big Lagoon,
October 13, 1957
53
Distribution of Chlorinity in Vertical Section, Big Lagoon,
November 26, 1957
54
Distribution of Chlorinity in Vertical Section, Big Lagoon,
April 19, 1958
55
Chlorinity Fluctuations Due to Tidal Influx at Station A,
Big Lagoon, June 17, 1957, Low Tide: -.1 at 0940 Hours
56
Distribution of Oxygen in Vertical Section, Big Lagoon,
November 16, 1956
59
Distribution of Oxygen in Vertical Section, Big Lagoon,
December 31, 1956
60
Distribution of Oxygen in Vertical Section, Big Lagoon,
February 19, 1957
61
Distribution of Oxygen in Vertical Section, Big Lagoon,
August 7, 1957
62
21
22
23
24
25
26
27
28
29
30
31
32
33
34
vii
LIST OF FIGURES (Continued)
PAGE
FIGURE
35
36
37
37a
38
39
40
41
42
43
44
45
Distribution of Oxygen in Vertical Section, Big Lagoon,
October 13, 1957
63
Temperature-Depth Diagrams Showing Typical Summer and
Winter Conditions at Big Lagoon
65
Maxima-Minima Water Temperatures of Big Lagoon for the
Period 1956-1957
66
Distribution of Temperatures in Vertical Section, Big
Lagoon, February 19, 1957
67
Distribution of Temperature in Vertical Section, Big
Lagoon, July 1, 1957
68
Distribution of Temperature in Vertical Section,Through
Stations A, B, C, and D, Big Lagoon, July 16, 1957
69
Distribution of Temperature in Vertical Section,
Big Lagoon, August 7, 1957
70
Distribution of Temperature in Vertical Section,
Big Lagoon, August 8, 1957
71
Distribution of Temperature in Vertical Section,
Big Lagoon, August 10, 1957
72
Distribution of Temperature in Vertical Section,
Big Lagoon, October 13, 1957
73
Distribution of Temperature in Vertical Section,
Big Lagoon, November 26, 1957
74
Distribution of Temperature in Vertical Section,
Big Lagoon, April 19, 1958
75
ΙΝΤ R Ο DUC ΤΙΟΝ
In the Fall of 1956 Humboldt State College, the Wildlife
Conservation Board of California, and the California Department of
Fish and Game entered into contract to study the possibilities of
using the Northern California Coastal Lagoons as supplemental rearing
areas for anadromous fishes such as salmon and trout. Fresh and salt
water impoundments are being utilized by the management agencies of
the Pacific Coast in an attempt to increase the survival rate of these
fishes in fresh water and possibly to improve their marine survival
rates. The use of such rearing areas seems particularly desirable
in Northern California as this region has very few hatchery sites
considered to be favorable. At the present time, Cedar Creek Hatchery
in Mendocino County is the only one in operation in the north coast
region. Because of the great economic importance and present critical
situation of the king salmon (Oncorhynchus tshawytscha) and the importance of silver salmon (Oncorhynchus kisutch) and steelhead trout
(Salmo gairdneri gairdneri), the project was designed to concentrate
on these species. The coastal studies of lagoons in California have
started with Big Lagoon in Humboldt County and subsequently are to be
expanded to other areas.
Since the success of the lagoons as rearing areas is directly
associated with the environment of the lagoon, it is obvious that a
study of the physical and chemical characteristics of the lagoon would
be the initial phase of the study. It is with the results of this
2
phase of the project that this paper is concerned. Actual work on this
project commenced in September of 1956 and is currently being carried on
under the supervision of Dr. Ernest 0. Salo, Associate Professor of
Fisheries, Humboldt State College.
Little success was met with in obtaining written information
concerning lagoon studies of a nature such as the Big Lagoon study,
and closely related literature was found to be extremely scanty.
The State of Washington Department of Fisheries is now engaged
in the use of lakes and lagoons on an increasingly large scale, partially
due to the successes met with in the Deschutes Basin near Olympia,
Washington. Originally the Deschutes Basin was a small inlet at the
mouth of the Deschutes River. This apparently ideal salmon stream was
blocked by a series of high falls. During the 1930's a highway was built
on an artificial bar constructed across the mouth of the Deschutes River,
which formed a lake or basin. Tidal gates were installed to allow the
exchange of fresh and salt water between Puget Sound and the basin. In
1945, 414,470 hatchery-reared fingerling chinook salmon were released in
the Deschutes Basin. From this planting the percent of returning threeand four-year-olds to the stream was a phenomenally high 1.64. Subsequent
plantings have met with similar success (Ellis, 1957).
Lagoon studies have also been undertaken in recent years in Italy,
but on a much larger scale than in the United States (DeAngelis, 1952a).
Hοwever, there the situation is somewhat different than that encountered
at Big Lagoon. The lagoons of Italy all have perennial connections with
the ocean, and do not have runs of salmonoids. The Italian fishermen have
been exploiting these lagoons for centuries, but it is just recently that
their potential has been realized by the fisheries agencies of that country.
3
Valliculture (the scientific breeding and rearing of marine fish) is
increasing. Many of these natural lagoons have been converted to valles
(managed lagoons) by altering their physical features. All fishing is
done on the commercial scale, employing devices called lavorieros, which
are large fish traps made of reeds placed strategically around the mouths
of the lagoons. The less productive lagoons are being considered for land
reclamation, because economically it is more feasible to dike them and
raise agricultural crops than to use them for fish production.
METHO D S , MAT E R I A L S, AND
SOURCES
OF
ERROR
VERBAL CONFERENCES
In lieu of published data, a great deal of information was obtained from verbal conference with Dr. Harry MacGinitie, Humboldt State
College, concerning the geology of Big Lagoon; Mr. Richard Warner,
Resident Engineer, Division of Highways, on the physical conditions
associated with the lagoon; and members of the California Department
of Fish and Game.
Weather data was secured from The California-Hammond Branch of
the Georgia-Pacific Lumber Company weather station at Big Lagoon and
from Prairie Creek State Park.
METHODS USED IN THE PHYSICAL AND CHEMICAL SURVEY
OF BIG LAGOON
Mapping
Mapping was accomplished by the use of an alidade and accessory
equipment. A hand line calibrated with one-foot intervals was employed
to sound the lagoon. The distance between each sounding was determined
by the slope of the bottom; that is, the more even the bottom the less
frequent the soundings.
The area was sectioned and six representative stations (A, B, C,
D, E, and F) were set up (Figure 1). An anchored buoy with a marker flag
was placed at each station for identification. Some drifting of the
5
markers took place and some were lost for unknown reasons; therefore it was
extremely difficult to retain the exact station positions. By correlating
observed depths with successive readings on the State Department of Highways
gauge on the Big Lagoon Bridge, slight discrepancies in location of stations
were noticeable.
Water Sampling
A sixteen-foot Glaspar boat, powered with an eighteen-horsepower
engine, was equipped with a portable heavy-duty winch and meter wheel to
handle the heavier gear such as Hansen reversing bottles and reversing
thermometers. Most of the water samples were taken by hand with standard
Kemmerer-type water bottles, The bottles were fastened to a one-eighthinch plastic line which was graduated every two feet. Tests revealed no
significant difference between samples taken with Kemmerer bottles and
samples taken with Hansen bottles.
As a great deal of detailed literature is available on the chemical
tests employed in this study, it is felt unnecessary to go into great detail
on the tests used, except where physical circumstances required alteration
or modification.
Salinity Determinations
The standard Mohr (1856) method as adapted by Oxner and Knudsen
(1920) using silver nitrate and potassium chromate as an indicator was
employed for the determination of the chlorinity of sea water. Ordinary
volumetric laboratory instruments were used in all determinations and
not the special Knudsen pipet or buret. Normal water of the Copenhagen
Hydrographic Laboratories was used to standardize the silver nitrate.
6
All samples were stored in 250 milliliter flint glass bottles with
rubber stoppers. No samples were tested in the field. All samples were
analyzed in the campus laboratories where they were kept one to four days
before being titrated. When the samples were kept over a day, they were
stored under refrigeration and then allowed to set out in the laboratory
at least twelve hours to allow them to reach room temperature. Tenmilliliter samples were used for titration. The following calculations
were used to determine the chlorocity (c1v):
(ml ΑgΝ03) (Normality ΑgΝ03) (35.46) (1000)
(1000) (10)
Titrations were run on each sample until the deviations were less
than 0.02 milliliter.
Oxner and Knudsen (1920) found that an error of 0.01 to 0.02
milliliter could be evident if one waited more than two minutes to read
the miniscus, or a slight deviation in the color of the end point could
give an error of the same magnitude. They also showed that an error of
similar order could be introduced if the titration time takes more than
four minutes. In order to minimize error these points were avoided, all
except the end point color which was a matter of degree and could not be
avoided entirely. Therefore, a possible maximum error of
1.80 percent
in chlorinities (about 3.00 0/00) may be due to the chemical techniques
alone, but as chlorinities increase, the percentage decreases to approximately 0.30 percent.
Chlorinity per liter (chlorocity clv) was converted to chlorinity
per kilogram (chlorinity clw) as a function of the following equation
(Knudsen, 1901):
Clw = 0.008
0.99980 clv - 0.001228 c1',2
7
Salinity was taken from Knudsen's Hydrographic Tables (1901)
and was found to be a function of chlorinity expressible by:
S = 0.030 + 1.805 cl 0/00 (parts per thousand)
where S is the salinity and cl is chlorinity. .
Dissolved Oxygen Determinations.
For all dissolved oxygen determinations, the method of Winkler
(1888) as modified for sea water was employed. The basis for the determination of dissolved oxygen depends upon oxidation of manganous hydroxide
by the dissolved oxygen in the sea water, resulting in the formation of a
tetravalent manganese compound. Upon acidifying the sea water containing
the tetravalent compound, free iodine is liberated from potassium iodide
that has been introduced into the solution. This free iodine is equivalent
to the amount of dissolved oxygen present and is determined by titration
with a solution of sodium thiosulfate that has been standardized against
standard iodine solution, which in turn has been standardized against
known sodium arsenite solution.
All samples were taken with a Kemmerer bottle, with a glass tube
fixed to the spout of the sample bottle to prevent excess agitation of the
sample. The samples were stored in 250 milliliter amber glass-stoppered
bottles. Because of the distance involved, samples were fixed immediately
by adding, in order: one milliliter manganous sulfate solution, one
milliliter alkaline iodide, and one milliliter concentrated sulfuric acid.
In this manner samples could be stored for four or five days without any
adverse effects.
Dissolved oxygen concentration was recorded in milliliters of
oxygen at NTP in one liter of sea water at 20 degrees centigrade (C).
8
For water samples nearly saturated with oxygen, the error in
a determined value is about 0.02 milliliter per liter of sea water.
The presence of hydrogen sulfide or other reducing substances
that react readily with elementary iodine, or sea waters containing
oxidizing substances that will react with iodide ions, causing the
liberation of free iodine, will render the accuracy of this method
invalid. Although no test for 112S was made at Big Lagoon, the presence
of this foul-smelling gas was undetectable by physical senses.
Phosphate Determinations
Although phosphates are not recorded in this report, an attempt
was made to develop a rapid quantitative test that could be carried out
in the laboratory with a minimum of time. Although this attempt was unsuccessful, it is felt that it is of importance to students confronted
with this same problem to list in the report the approach taken.
The method of Deniges (1920) is based on the principle that when
a sulfuric acid solution of ammonium molybdate is added to a soluble
phosphate solution, a complex phosphomolybdic acid is formed. Upon
treatment with a reducing agent, such as stannous chloride, the complex
acid is reduced to a blue-colored substance believed to have the composition H3PO4•(4Μ003•Μ002)2.4H120. The color developed is proportional
to the concentration of the phosphate. Once these colors are developed
for samples, they can be compared against known concentrations of phosphates
by the use of Nesseler tubes and subsequent phosphate concentrations of the
samples can be determined. The major difficulty with this method in a
situation such as that encountered at Big Lagoon is the length of time
required to run the samples. Big Lagoon may exhibit a wide variety of
9
chlorinities at the same time and since the standards used in the Deniges
method are valid for variations of ± 1.00 0/00 incchlorinity, this would
necessitate the mixing of a prohibitive number of standards. Therefore an
attempt was made to develop a rapid quantitative test for phosphate with the
equipment available on the campus. Known concentrations of phosphate from
0.10 to 2.00 microgram atoms were prepared for chlorinities from one to twenty
parts per thousand in increments of one part per thousand. These samples were
then placed in test tubes especially adapted for the Scharr Lumetron Colorimeter. Using a 580 Filter, the light transmission through the sample was
recorded. These were then plotted with the concentration of phosphates in
microgram atoms on the Y scale and percent transmission on the X scale. One
graph was made for each one part per thousand change in chlorinity. It was
then inferred that by fixing the blue color to the sample, as described by
Deniges, the phosphate concentrations could be measured by observing the
light transmission through the sample and then interpolating from the previously calibrated graphs. Although the reasoning behind this method seemed
to be sound, actual testing of the samples showed too wide a variation for
reliable reporting. As a result, a very important phase of this study had
to be eliminated.
Temperature Determinations
All temperatures were taken with a standard centigrade thermometer
graduated to five-tenths of a degree. This thermometer was calibrated
against a thermometer that had been checked by the U.S. Bureau of Standards.
The most satisfactory method developed and used for all sampling
was to immerse the thermometer in the water in the sample bottle immediately
after hauling aboard. This method was checked with a reversing thermometer
10
and found to be accurate to within ± 0.2 of a degree. As interpolation of
the thermometer used was accurate to 1 0.2 of a degree, the results reported
in this paper can be stated to be accurate to ± 0.4 of a degree.
Stream Flow Determinations
The method of Embody (1927) was employed in determining stream flow
and is described by the following formula:
R = WDaL
T
where R is equal to the volume of flow in cubic feet per second (CFS), W is
the average width in feet, D is the average depth in feet, L is the length
of the section measured in feet, a is a constant for correction of stream
velocity, and Τ is the average time in seconds required for a float to traverse
the distance L. Fixed stations were established on the creek and stream flows
were always determined at these same locations.
METHODS USED IN THE STUDIES OF FISH POPULATIONS OF BIG LAGOON
Gill Νetting
Two diver-type nylon gill nets were employed for the major portion
of the fish sampling in the lagoon. Both nets were 120 feet long and 12
feet deep. One net was made with one-inch-stretched mesh and the other with
four-inch-stretched mesh. The nets were always fished overnight.
Seining
All fish samples from Maple Creek were taken with two-man seines.
A number of seines from five to fifty feet long were used. The sizes were
generally one-eighth or one-quarter inch square mesh.
11
Fig. 2. Nap of the Maple Creek Drainage Showing Pitcher Creek and Big
Lagoon
12
Creel Censusing
For conducting creel censusing, the lagoon was divided into three
survey areas: (1) the boat dock at the south end of the lagoon, (2) shoreline fishing, and (3) Highway 101 bridge. A crew of two samplers equipped
with scales, measuring boards, and creel census forms was stationed at each
of the survey areas.
Population Estimates in Maple Creek
Mark-sample extimates with the fish being captured by seining were
employed in estimating the populations of salmonoids in Maple Creek. The
wild fish captured were given temporary marks by fin-nipping, released, and
after a period of several weeks were sampled for the mark-unmarked ratio.
Care was taken to sample, release, and recover as randomly as possible.
During the period of marking, low stream flows facilitated the seining in
riffles and shallow pools, although the sampling area contained some pools
that could not be seined. In order to detect any migration or mixing
patterns, different marks were used for different areas All fish recovered
during sampling were given either a new or an additional mark and re-released.
Population densities were much greater within three miles of the
mouth of Maple Creek than in the upper areas. Sampling above the falls on
the North Fork revealed no fish and the catch above the falls on the South
Fork was negligible. Sampling was confined, therefore, to the area below
the falls (Figure 2).
All trout regardless of species were called steelhead.
N = -ngt- was used for population estimates, where N was the estimated
size of the population, n was the number of fish sampled during recovery,
t was the number of fish marked prior to recovery, and s was the number of
marked fish in the sample.
13
The methods used to determine the confidence limits (95 percent)
were those suggested by Chapman (1948). The binomial approximations
(Clopper-Pearson, 1934) and normal approximations (Ricker, 1937) produced
estimates within ±1000 fish to the figures obtained by the Poisson
approximation for the steelhead population. Only Chapman's methods were
used on the silver salmon population.
RESULTS
GEOLOGICAL HISTORY OF BIG LAGOON
A typical lagoon delta as described by Hinds (1942), Johnson (1919),
and others, is generally a body of water that is separated from the ocean by
an offshore bar. The stipulation generally is made that the lagoon has a
continuous connection with the ocean or that the lagoon is a body of water
separated from the ocean and between which a free exchange of water does not
take place except by washing over during periods of high tides and storms.
Yoshimura (1938) has described many coastal bodies of water in Japan that
correspond tο the latter as "meriomictic lakes".
Big Lagoon was found to be a combination of both of the above for
at certain times of the year it has a continuous opening to the sea and at
other times there is no opening to the sea. At certain periods, high tides
combined with strong westerly winds wash sea water over the bar into the lagoon.
As far back as geological records can be traced, there is evidence
that the shorelines of the world are dynamic, subject to rises and falls in
sea level, and elevations and depressions in land masses. Recent geological
history tells us that this same situation has existed along the Humboldt
coast (MacGinitie, 1952). Evidence of these things can be readily observed
at a number of sites.
By looking eastward from the town of Trinidad, Humboldt County,
marine terraces and old beach lines can be seen rising step by step to an
elevation of 1400 feet. This is clear evidence of the successive elevations in land masses along this coast.
15
Conversely, evidence of land depression is just as readily seen.
Brainard's Cut on Highway 101, about three miles south of Arcata, substantiates evidence of land depression. Sand dunes that were formed many
centuries ago are presently extended below the level of the bay water.
Additional proof of this land depression is also apparent if correlated
with the distance to which the high tide invades the Eel River from its
mouth to Fernbridge, a distance of about three miles.
Coupled with these two geological phenomena is the fluctuating
sea level, which has been rising since the beginning of the last ice age.
It presently is rising along our northern coast (Russell, 1957). All the
north coast from San Francisco Bay northward has recently been subjected
to depression or down warping of the land with respect to the ocean.
Formation of the Lagoon
All of these facts have entered into the formation of the north
coastal lagoons. At Sig Lagoon, faulting was probably the most significant
of these factors, evident in the soft sandstone along the beach to the south
of Big Lagoon. This sandstone is tilted downward to the north; at one time
it was level. This same sandstone extends along the floor of the lagoon
until, at the north end of the lagoon, it abruptly stops where it meets a
rocky bluff. This change from a soft sandstone to rocky bluff marks a line
of fault, wherein the land has risen to the north and sunk to the south.
This depression lowered the floor of Maple Creek Valley and allowed the
ocean to flood in, thus forming a bay. Sediment deposited at the head of
the valley by Maple Creek formed a delta. The rising sea level extended
the bay even farther into the valley.
ιό
Along-Shore Currents and the Formation of the Sand Bar
Wind-driven alongshore currents were the significant forces in
forming the bar which made the small bay into a lagoon. The southeasterly
winds of the winter caused a northerly-flowing alongshore current while
during the summer months the persistent northwesterly winds cause a
southerly-flowing current.
These currents transported large amounts of sediment from heads of
land such as Patricks Point to the south and a similar point to the north
that projected into the sea. In situations such as these, surf and wave
action have their greatest eroding effect. At this point it should be
stated that the ability of a body of water to transport suspended material
is directly proportional to the speed of that body of water. As these
swiftly-moving, sediment-laden currents met the deep waters off the mouths
of submerged valleys, their speed slackened and they deposited portions of
their load. Thus, over the years, the incessant vigor of the current would
transport huge quantities of sand to the lagoon. This was the beginning of
the bar that now extends across Big Lagoon, separating it from the sea.
This bar was the result of many years of current action, building spits to
the north in winter and to the south in
summer. Finally, when the two spits
were joined in the middle, the result was a solid bar across the lagoon.
The final stages in the formation of the bar were a result of the
combined efforts of wind, currents, and waves. Although the waves would
appear to have more of an eroding effect on the bar than a building effect,
they nevertheless did build up the bar as fast as they eroded it. Material
brought in from the north and the south was deposited upon the lagoon bar by
the breaking waves. At low tide, winds piled sand still higher on the bar.
Fig. 3. Map of Humboldt
County Legoons
18
Geological Future
With the passage of time two processes seem to destroy lagoons.
The headlands slowly retreat shoreward and under the force of the waves
the bar also retreats shoreward. In addition to this, the streams at
the heads of lagoons deposit sediment which forms deltas that encroach
upon the aquatic domain of the lagoon, thus eventually filling it in.
Clear evidence of this latter aspect is readily observable in Dry Lagoon,
which is situated just a mile or so north of Big Lagoon. The amount left
of the original water area in this lagoon is almost negligible when compared with that of Big Lagoon, Stone Lagoon, or Freshwater Lagoon. Dry
Lagoon has filled in from the headlands by stream deposition and from
the seaward by wind-blown sand. The final stage of the lagoon will be
similar to the Clam Beach area, just south of Little River - a filled
alluvial bottom fringed to the seaward by sand dunes and a sandy beach.
PHYSICAL DESCRIPTION OF BIG LAGOON AND ITS WATERSHED
Big Lagoon is situated 24 miles north of Arcata, California, on
Highway 101. It is the southernmost of a series of four lagoons located
within eight miles of each other (Figure 3).
The lagoon is about 3.5 miles long and about 1.3 miles at the widest
point. When the lagoon is 25 feet deep at its deepest point, a typical summer
condition, it covers an area of 1470 surface acres. To the west the lagoon
is separated from the ocean by a sand bar about 3.2 miles long which averages
700 feet wide at mean low tide (Figure 1). To the northeast the shore is
rocky and irregular with the dominant vegetation being coyote brush (Baccharis
pilularis), blue blossom (Ceanothus sp), salal (Gaultheria shallon), sitka
1
9
Fig.
4.A
erial View of North End of Big Lagoon
Fig. 4a.
AerialView of SouthEnd of Big Lagoon
20
21
spruce (Picea sitchensis), azalia (Rhododendron sp), and redwood (Sequoia
sempervirens). The major portion of the southeast shore consists of low
marshlands with dominant growths of sedge (Carex sp) and silverweed
(Photentilla anserina).
The cross section of the lagoon basin is saucer-like in shape.
When the lagoon is open, due to breaching of the bar, the depth may be
reduced to 21 feet at its deepest point. Prior to any ορ ning of the
lagoon, the depth reaches 33.5 feet, giving an annual oscillatory range
of about 12.5 feet.
The major portion of the basin bottom is composed of soft muddy
ooze. Virtually no plant life has been observed growing on the bottom
except in the area just west of the 101 bridge.
Big Lagoon Bar
As described above, Big Lagoon is formed by a 3.2 mile sand bar
that separates it from the ocean (Figure 4). This her is not stable, but
is subject to opening and closing during certain times of the year.
The opening of the lagoon is dependent upon the natural forces of
rain and tide. In order to aid in the understanding of this phenomenon it
is convenient to begin the discussion of a typical breaching cycle with the
normal summer period. At this time the lagoon is 25 feet deep at its deepest
point. This represents the lagoon surface as being about 3 feet above mean
sea level. With the advent of the rainy season, the basin begins to fill and
the depth of the lagoon increases. As the lagoon approaches its maximum
level, the sand particles of the bar become buoyant in the surrounding water
medium. As seepage through the bar from the lagoon to the ocean takes place,
the particles of sand become so buoyed that the bar fractures instantaneously,
in quite a spectacular fashion. This breaching action takes place when the
Fig.
5.
Discharge of Big Lagoon Waters After Breaching, Looking South
22
23
Fig. 6. Discharge of Big Lagoon Waters After Breaching, Looking West
lagoon surface is generally at a point 33 to 34 feet above the bottom, or 11
to 12 feet above mean sea level. The rate of discharge is closely correlated
with the level of the tide. The lower the tide, the more rapid is the discharge
until the lagoon surface reaches sea level (Figures 5 and 6).
The process is best described by Rowe and Royce (1953) and is quoted:
"The forces of wind, wave, and tide are persistent in
building the strand and maintaining a natural dam, holding
the lagoon surface higher than the sea. Fresh inflow raises
the lagoon surface, with little loss by evaporation in this
climate, but with seepage loss through the strand increasing
with the differential in stage. In some lagoons with small
inflow, like Stone and Freshwater, seepage offsets inflow for
all but very infrequent floods, but Big Lagoon has a large
tributary area which raises the water surface too high for
seepage relief two to five times a year. The strand breaches
and evacuates the lagoon in dramatic fashion, after which
natural forces repair the breach for a repetition of the cycle.
The mechanics of breaching are a combination of buoyancy
and erosion, not necessarily triggered by overtopping. Simple
overtopping- of the crest of the strand transports water and
sand to the foreshore where the water sinks and the sand upgrades the shore, with the effect of moving the strand seaward.
Many attempts to abort the lagoon have failed because of this
autonomous healing of hand-dug pilot channels. However, as the
seepage horizon rises, sand particles are buoyed to the point
of quickening and the strand disrupts catastrophically. Before
the breach can be healed by littoral drift, the lagoon's outpour
widens the breach by erosion. Under heads up to 23 feet, critical
outflow would generate velocity up to 22 feet per second, eroding
rapidly but increasing area and diminishing velocity until
achieving a balance. A breach at. low tide may widen quickly to
500 feet and discharge 100,000 sec.-ft. At high tide, the breach
may be as little as 100 feet wide, cresting at 10,000 sec.-ft.
"Elevation of strand and lagoon surface just before a break
is affected by magnitude and direction of wind waves and swell.
Historical data is largely qualitative, but from the appended
record of quantitative observations a stage of 19.8 was observed
in 1931 and 20.0 was reported prior to 1924. At other times
when these stages were approached, the lagoon was aborted.
Following breaks, stage has been observed as low as El 2.5, but
this was the level of Maple Creek flowing in a narrow channel
under the bridge; the residual lagoon was probably as low as
El 2.0, which is approximately at mean sea level.
"The reported stage of 20.0 prior to 1924 is shown on the
old layout and is believed to be contemporaneous with an oral
description by R. L. Thomas of the only break known to have
occurred at the south end of the strand. Heavy seas had
25
Fig. 7. Openings of Big Lagoon Bar Showing Intermittent Lagoon
Levels and Monthly Rainfall for the Period October
1956 to January 1958
27
prevented a break at the north end, raising the lagoon
stage until it broke through at the next weakest spot.
In 1931 our maintenance men spent several days trying
to abort the lagoon and succeeded when the stage reached
19.8. Probably there was a recurrence of the same sea, with
a probable breach at the south end prevented by the abortion.
Hence it is concluded that El 20 is attained or approached
often enough for design, and that it will not be exceeded
such for any combination of wind and tide."
The stage figures referred to by Rowe and Royce (1953) are those
listed under "Old C.H.C. Datum" in their Report to the Highway Department, 1953.
Contrary to Rowe and Royce (1953), Stone Lagoon does open almost every
year; the openings are in the same manner as those at Big Lagoon. Freshwater
Lagoon does not open as a spillway was built through the bar to allow excess
water to run off in order to accomodate a highway along the bar.
Once the lagoon has drained to sea level and the force of the outflowing water has ceased, the action of the wind, waves, and tides begin their
build-back of the bar. This can be observed quite readily by daily inspection
from the cliffs situated along the extreme northeast shore of the lagoon. As
the northerly along-shore currents carry their loads of sand and deposit them
at the end of the spit, the spit can be seen to prοgress nοrtherly until it is
continuous with the north shore. The new portion of the bar is built higher
with each succeeding high tide, until the action of the surf and wind apply
the finishing touches. Thus a restored bar is now able to impound the waters
of the lagoon. This cycle may be repeated many times throughout the winter,
dependent upon the amount of rainfall. Figure 7 shows the number of openings
in the lagoon for the period October 1956 to January 1958, correlated with
monthly rainfall.
Tributaries and Drainage
Three streams, Tom Creek, Maple Creek, and Pitcher Creek supply
virtually all of the water entering the lagoon and furnish all of the
28
Table 1
Observed Water Temperature and Stream Flow Data from
Maple Creek for the Period March 3, 1957 to October 11, 1957.
View of M
rig. U. Aerial
leCreek
Watershd
29
30
Fig.
9.
Monthly Variation of Streamfloν, Air Temperature,
Stream Τemperature and rainfall for the South Fork
of Maple Creek for the Period March to October 19S1957
31
32
spawning areas available to salmonoids (Figures 1 and 2).
Maple Creek, the largest of the three, consists of two branches that
unite 1.5 miles above the entry of the main stream into the lagoon.
The north branch is approximately 5 miles long; however, only 3 miles
are available to anadromous fish because of a 50-foot impassable falls. The
south branch is about 15 miles long; it has a barrier located 3.5 miles above
the fork (Figure 2).
The south branch supplies two-thirds of the toal flow of the stream
(Table 1), which is as high as 2000 cubic feet per second during flood stage
and as low as 5 cubic feet per second during the low-flow period in late summer.
For the period March 1957 to October 1957 the mean flow of the south branch
was 20 cubic feet per second. (Table 1).
The mean water temperatures for this same period were 63.8 and 63.0
degrees Fahrenheit for the north and south branches respectively.
The Maple Creek drainage area covers about 46.8 square miles (Rowe
and Royce, 1953). The major portion of this area has been heavily logged and
the resultant accelerated runoff (Figure 8) contributes to the causes of the
extreme ranges in stream flow. This stream flow pattern is typical of the
streams associated with logged-off areas (James, 1956, and U.S.D.A., 1940).
There is an inverse correlation between water temperature and rate
of stream flow and there is a direct relationship between air temperature
and water temperature (Figure 9).
Tom Creek originates in a logged-off area north of the lagoon, flows
through an area of first-growth redwood, and empties into the lagoon 1.5 miles
north of Highway 101 bridge. Although the total length of the stream is about
6 miles, only l.5 miles are available to migrating fish as a falls at this
point is considered impassable (Legate, 1957). The average flow is about 7.3
33
Fig. 1O. Stream Temperature and Flow, Tom. Creek, October to
September 1957
34
Fig. 11. Average Monthly Rainfall and Cumulative Rainfall at
Big Lagoon for the Period October 1, 1956 to September
30, 1957 Compared to a Nine Year Monthly Average
35
Table 2
Average Hourly Wind Velocity and Prevailing
Direction for Eureka, California.
36
cubic feet per second with an average temperature of 46.7 degrees Fahrenheit
for the period January 1 through May 30, 1957 (Figure 10).
Pitcher Creek is a small creek that empties into Maple Creek about
one mile above its mouth (Figure 2). No measurements were made on Pitcher
Creek; however it was observed that in June the rate of flow was in the magnitude of three to five cubic feet per second. During this time seining was
being conducted in Maple Creek and the water flowing in from Pitcher Creek was
noticeably cooler, recorded at 51.0 degrees Fahrenheit. This hints at a
possible spring origin.
CLIMATOLOGICAL FEATURES
Rainfall
Figure 11 shows the cumulative rainfall, and the average monthly
rainfall, recorded for the period October 1956 to September 1957, with a
comparison to the nine-year monthly average. The annual total for this
period was 66.2 inches. This fell very close to the nine-year average of
67.1 inches. The monthly averages for the October 1956 to September 1957
period did not follow as close to the nine-year average as did the total
rainfall. The significant rainfall was confined to the winter months, and
during the dry summer months there was no great contribution of fresh water
to the lagoon.
Wind
The nearest available wind data came from the Eureka area as recorded
by Fleming et al (1955). Monthly directional and velocity averages for 44
years are shown in Table 2. The prevailing summer winds are northerly and the
prevailing winter winds are southerly (Table 2).
37
Fig. 12. Average Monthly Fog Incidence Compared with the Average Monthly Temperature for the
Eureke Area
38
Fig. 13. Mean Maximum - Minimum Air Temperatures, Prairie Creek State Park, 1956 - 1957
39
The presence of fog in the summer months is a definite limiting
factor in affecting the amount of evaporation. Fleming et al (1955) found
that the greatest periods of fog occurred from July to December. The months
of June, July, August, and September are the warmest of the year. These
should also be months of high evaporation, but the evaporation rates are kept
at a minimum by the high incidence of fog. Figure 12 shows the monthly
average temperature plotted against an index of fog for Eureka, California.
Temperature
Air temperature records are not kept at the Hammond weather station
located at Big Lagoon; therefore it was necessary to obtain records from
Prairie Creek State Park, the next closest recording station which is situated
approximately 10 miles north of Big Lagoon. The temperatures there are
slightly lower than those of the Maple Creek drainage area, but generally
somewhat higher than the air temperatures over the lagoon. There was a great
difference in air temperatures in the summer between the area immediately
over the lagoon and areas short distances inland from the lagoon. On numerous
occasions when the lagoon area was foggy and cold, the weather about onequarter to one-half mile inland was sunny and warm. Differences were as great
as ten degrees or more.
The warmest temperatures were confined to the months of June, July,
and August, while the coldest months were December, January, and February
(Figure 13). The maximum and minimum temperatures recorded for the 1956-1957
period was 83 degrees and 22 degrees Fahrenheit respectively (Table 3).
40
Table 3
Air Temperature Data for the Period 1956-1957
from Prairie Creek State Park.
41
Fig. 15. Salinity-Depth
Diagram Shσwing Salinity
Anomaly at Station C,
Big Lagoon on August 8,
1957
42
Fig. 16. Distribution of Chlorinity
in Vertical Section Across Station B
and C, Big Lagoon, November 15, 1956
43
Fig. 17. Distribution of Chlorinity in Vertical Section, Big
Lagoon, November 16, 1956
4
Fig. 18. Distribution of Chlorinity in Vertical Section, Big Lagoon, December 31, 1956
45
Fig. 19. Distribution of Chlorinity, Oxygen
and Temperature in Vertical Section Across
Stations C and D, Big Lagoon, January 3, 1957
46
Fig. 20. Distribution of Chlorinity in Vertical Section, Big Lagoon, February 19, 1957
47
Fig. 21. Distribution of Chlorinity in Vertical
Section, Big Lagoon, April 9, 1957
148
Fig. 22. Distribution of Chlorinity in Vertical Sectiοn Through Stations A, B, C, and D,
Big Lagoon, July 7, 1957
49
Fig. 23. Distribution of Chlorinity in Vertical Section Through Stations A, B, C, and D,
Big Lagoon, July 16, 1957
Fig. 24. Distribution of Chlorinity in Vertical Section, Big Lagoon, August 7, 1957
50
Si
Fig. 25. Distribution of Chlorinity in Vertical Section, Big Lagoon, August 8, 1957
52
Fig. 26. Distribution of Chlorinity in Vertical Section of Big Lagoon, August 10, 1957
53
Fig. 27. Distribution of Chlorinity in Vertical Section, Big Lagoon, October 13, 1957
Fig. 28. Distribution of Chlorinity in Vertical Section, Big
Lagoon, November 26, 1957
55
Fig. 29. Distribution of Chlorinity in Vertical Section,
Dig Lagoon, April 19, 1958
56
Fig. 30. Chlorinity Fluctuations Due to Tidal influx
at Station A, Big Lagoon, June 17, 1957, Low Tide:
-.l at 0940 Hours
57
CHEMICAL DESCRIPTION OF BIG LAGOON
Salinity Patterns
The salinity patterns in Big Lagoon were found to be extremely
variable. Even while the lagoon was closed, day to day differences in
stratification were evident (Figures 24 and 25). This is also borne out
by many salinity anomolies (Figures 14 and 15). These changes are due
to a number of factors, with wind being most significant. During the
summer months these changing salinity patterns are least active because
little fresh water is added to the lagoon, and dynamic physical forces
such as wind, density changes, and temperature changes which cause water
movements are at a minimum. However, it should not be inferred that there
is no water activity per se during the summer; the waters are active, but
less so than during the winter months.
During the summer of 1957 the highest chlorinity recorded was 17.40
°/oo at a depth of 20 feet; at the same time the surface chlorinity was
15.60 0/00 (Figure 22). This high concentration of salt water was probably
an atypical situation, resulting directly from a comparatively late artificial opening of the lagoon on May 7, 1957 by the Highway Department.
Ordinarily the lagoon would not have opened naturally until fall. Just
prior to the lagoon closing on July 1, 1957, there was an extreme range
of tides which resulted in a greater than normal content of salt water being
entrapped when the lagoon closed. The total concentration of chlorinity on
November 26, 1957 was approximately 20 percent higher than on November 15,
1956 (Figures 16 and 28).
During the rainy winter months when there were severe ocean storms,
the lagoon was found to be most active, i.e., dynamic forces which cause water
58
movements are more influential. During this time the lagoon seemed to take
on no definite pattern and salinity stratification varied greatly with the
opening and closing of the lagoon (Figures 20, 21, and 29).
The upper layers of the lagoon often exhibited salinities that were
greatest at Station A. These salinities decreased from station to station
in the following order: B, C, F, D, and E (Figures 16, 21, 23, and 29).
This fact was probably due to the washing of sea water over the bar and
seepage in and out of the bar.
Station E consistently had the lowest recorded salinity in the
lagoon at any time. This was due to two factors: (l) the shallowness of
the lagoon at this point and (2) the proximity of the station to the mouth
of Maple Creek. The lowest chlorinity recorded for this station was
00.05 0/00 (Figure 20).
As the winter rains continued, the lagoon filled, the bar breached,
and the waters of the lagoon were replaced by new salt water from the ocean.
It was during this time when the lagoon opened that a biological and chemical
rejuvenation took place, for as the lagoon broke open, the upper layers of
less dense water passed out through the opening in the bar to the sea. As
the tide rose, an influx of new sea water encroached on the lagoon (Figure
30). This fresh salt water moved along the lower depths of the lagoon,
forcing the old waters from the bottom of the lagoon to the surface where
they were flushed out to sea. The degree to which this flushing transpired
depended upon the height of the tide. With this fresh supply of sea water
came new chemical vigor and biological potential to the lagoon: oxygen,
dissolved nutrient substances, and a myriad sea life from plankton to seals.
After the initial closing it may be a matter of only two or three
weeks before enough rain has fallen to cause another breakthrough. It is
59
Fig. 31. Distribution of Oxygen in Vertical Section, Big Lagoon, November 16, 1956
Distribution of Oxygen in Vertical Section, Big Lagoon, December
31, 1956
60
Fig. 32.
61
Fig. 33. Distribution of Oxygen in Vertical Section, Big lagoon, February 19, 1957
62
Fig. 34. Distribution of Oxygen in Vertical Section of Big Lagoon, August 7, 1957
63
Fig. 35. Distribution of Oxygen in Vertical Section of Big Lagoon, October 13, 195?
64
believed that on occasion the lagoon opens only partially for a period of a
day or so and never quite drains to its normal extent. This cycle of opening
and closing may take place three to five times a year with the first breakthrough occurring in December and the last around March, dependent upon the
duration of the rainy season. By keeping a close watch on the water level
in the lagoon, an opening may be predicted as this generally takes place when
the lagoon is about 33 to 34 feet deep.
Seepage through the spit and washing over the bar during storms and
high tides will probably be found to account for many of the salinity anomalies
throughout the lagoon.
Oxygen Patterns
The first oxygen samples were taken on November 16, 1956. The results
showed that at this time there was a definite low-oxygen area below 14-16 feet
(Figure 31). The next samples were taken on December 31, 1956 after the lagoon
had opened and closed (Figure 31). The resultant exchange of lagoon water and
ocean water caused oxygen concentrations to be much higher. The area that had
exhibited low concentrations in November 1956 now exhibited oxygen concentrations ten times greater. Each month dissolved oxygen concentrations in the
lower levels progressively decreased (Figures 32, 33, 34, and 35). On October
21, 1957, oxygen samples taken at Station C ranged from 7.80 at the surface
to l.96 at the bottom. During the summer of 1957 an oxygen pattern prevailed
that resulted from the artificial opening of the lagoon late in the year, and
therefore probably is not typical.
The oxygen in the upper layers of the lagoon was replenished throughout the year by wind agitation, but in the lower layers no replacement of
oxygen was evident except when the lagoon was open to the sea.
65
Fig. 36. Temperature-Depth Diagrams Showing Typical Summer and Winter
Conditions at Big Lagoon
66
Fig. 37. Maxima Minima Water Temperatures of Big Lagoon for the Period 1956-1957
Fig. 37a. Distribution of Temperatures in Vertical Section, Big Lagoon, February 19, 1957
67
68
Fig. 38. Distribution of Temperature in Vertical Section, Big Lagoon, July 1, 195?
69
Fig. 39. Distribution of Temperature in Vertical Section Through Stations A, B, C, and D,
Big Legoon, July 16, 1957
Fig.
ho.
Distribution of Temperature in Vertical Section, Big Lagoon, August 7, 1957
70
8, 1957
71
Fig. 4i. Distribution of Temperature in Vertical Section, Big Lagoon, August
72
Fig. 42. Distribution of Temperature in Vertical Section, Big Lagoon, August 10, 1957
73
Fig. 13. Distribution of Temperature in Vertical Section of Big Lagoon, October 13, 1957
74
Fig. 44 . Distribution of Temperature in Vertical
Section, Big Lagoon, November 26, 1957
75
Fig. 45. Distribution of Temperature in Vertical
Section, Big Lagoon, April 19, 1958
76
The high degree of stratification of oxygen in the lagoon was due
partially to salinity gradients that prevent overturning in the lagoon. This
decrease in oxygen probably was a result of animal metabolism, inorganic decomposition, and lack of mixing.
Temperature Patterns
The temperatures of Big Lagoon took on distinctive patterns during
winter and summer. During the summer months a typical lake situation was
evident; the warmer waters were on top and the cooler layers were on the
bottom (Figure 36). The warmest temperature recorded during the summer was
22 degrees centigrade at the surface and at this time the bottom layers were
only slightly cooler - 21 degrees centigrade (Figure 37). With the advent
of the cold winter months the upper layers in the lagοοn began to cool. Even
though this cooling increased the density of the surface waters, it was not
enough to cause an overturn because of the high salt content of the waters of
the bottom layer. This situation was unchanged until the lagoon bar breached
and flushing took place. During the winter months the coldest surface temperature recorded was 5.6 degrees centigrade at the surface while the temperature
on the bottom was 11.1 degrees centigrade (Figure 37).
Mixing
Because of the complexity of the problem of mixing, no studies of this
process were undertaken, but it was apparent that the forces causing mixing were
at a minimum during the periods when the lagoon was closed and most significant
during that time when it was open. During the latter period almost complete
mixing took place in the lagoon, but while it was closed, only slight mixing
took place. The forces then present did not supply the amount of work required
77
to overcome the inertia of the highly stratified water for mixing to take
place. Yoshimura (1938) and Hutchinson (1957) found that in some meriomictic
lakes, dependent upon the density of the monimolimnion, very little or no
mixing took place in this layer.
Some insight into this problem of mixing may be had by the following
excerpts from Schijf and Schonfeld (1953):
"CLASSIFICATION OF MIXING MECHANISMS - Brackish water
is formed by mixing salt water and fresh. This mixing may
be brought about by quite different mechanisms.
"According to scale and regularity, the motion of fluid
particles may be distinguished into the following:
(1) Molecular movement
(2) Turbulence
(3) Average flow
All three kinds of motion may provide mixing.
"The thermal movement of the molecules and ions results
in a diffusion of salt from places with great concentration
to places with less concentration of salt. The scale of
this mixing mechanism is of the order of 10- 1 m. The diffusivity (coefficient of molecular diffusion) of salt in water
is of the order of 10-8 sq m per sec, which is very small,
even if compared to the kinematic viscosity (10- sq m per
sec), which is caused likewise by the molecular movement.
Hence, molecular diffusion is seldom of direct influence.
"The irregular motion which we call turbulence brings
elements of water from more saline into fresher layers, and
vice versa. Thus the surface along which the saltier and
the fresher water are in contact with each other is increased
considerably, which strongly promotes the formation of brackish
water by molecular diffusion.
"If the average flow follows such a pattern that quantities
of water with different salinities which were first separated by
a great distance, are brought in close proximity, the intermixing
by turbulence is made possible. The formation of brackish water,
ultimately, is again due to molecular diffusion.
"TURBULENCE IN A FLOW WITH A VERTICAL DENSITY GRADIENT As discussed previously, the salt-wedge in a tidal river may
be corrupted so that a brackish region is formed with a gradual
transition between rather saline water at the bottom, and
rather fresh water at the surface.
"The turbulence in a flow with such a vertical density
gradient undergoes the influence of that gradient.
"INTRUSION OF SALT IN AN ESTUARY - In an estuary with
a fresh water discharge, the salt may penetrate from the sea
against the expelling action of the flow of fresh water,
firstly in the form of a salt-wedge along the bottom. Inward
78
of this salt-wedge, and in the whole estuary if the wedge
is so corrupt that the vertical gradient is nearly absent,
the salt penetrates by horizontal diffusion.
"The upper layers in a flow usually have greater
velocities than the layers near the bottom. This means that
the paths of tidal excursion of the upper layers are greater
than those of the lower layers. Hence, the tides do not
only bring about an oscillating movement of the whole body
of water, but also an oscillatory shifting of the upper
layers relative to the lower layers.
"An element of water from an upper layer may therefore
descend to a lower layer by vertical turbulent diffusion,
stay there some time, and then return to the upper layer.
During this time the upper layer has progressed a certain
distance relative to the lower layer. As a result of this,
the element considered does not return to its initial
environment.
"It has thus been transported along the upper layer
by the intermediary of the lower layer. In the same way
a transport along the lower layer by the intermediary of
the upper layer is possible. This way of transport of
water has the effect of a diffusion."
In this report a corrupt salt-wedge is defined as a salt-wedge with
a wedgelike salt distribution with inclined isohalinic surfaces without a
sharp separation of salt and fresh water.
PRELIMINARY REPORT ON THE RESIDENT AND INTRODUCED POPULATIONS OF FISHES
Qualitative
A number of species of fish other than salmonoids were found in the
lagoon, many of them normally classified as strictly ocean fish and not usually
found frequenting brackish waters. The greatest variety of fishes were found
in the lagoon during the periods when it was open to the ocean. At that time
the fish entered the lagoon on feeding and spawning excursions. The distance
traveled into the lagoon by many of these ocean fish was directly correlated
with the height of the tide. That is, ocean species were more likely to be
found dispersed in the lagoon at high tides than at low tides. Many of these
79
Table 14
1. Check List of Fishes Taken in Big Lagoon
from January 1957 to December 1957.
Family
Species
Acipenseridae
Acipenser acuttrostris
Clupeidae
Clupea pallasii
Osmeridae
Salmonidae
"
Spirinchus starksii
Salmo gairdneri gairdneri
Salmo clarkii clarkii
Oncorhynchus kisutch
"
Merltcciidae
Gadidae
Merluccius productus
Microgadus promaxis
Bothidae
Citharichthys sordidus
Pleuronectidae
Platichthys stellatus
Atherinidae
Embiotocidae
sp
Cymatogaster aggregatus
Phanerodon furcatus
"
Gobiidae
Cottidae
Amphisticus rhodoterus
Sp
Leptocottus armatus
Cottus asper
Gasterosteidae
Syngnathidae
Gasterosteus aculeatus
Syngnathus sp
80
Table 5
Gill Netting Data from Big Lagoon
January 29, 1957 — August 30, 195?.
81
Table 6
ryofBigLanCelsu
Suma
April 27, 1957 to May 12, 1957.
Table 7
Summary of Big Lagoon Creel Census
May 3 and 4, 1958.
Adult
Juvenile
Fishermen
Time Fished
Hours Minutes
Steelhead
Cutthroat
Silver
Salmon
Boat
Landing
7
2
1
30
11
C
110
Shore
5
0
2
25
11
0
29
0
7
0
8
0
27
1.2
9
3
30
0
166
Area
10Bridge Highway
Totals :
Boats
12
67
Fish/hr/man = .14
Fish/man
= .24
83
fish were trapped in the lagoon when the bar closed. A check list of fish
taken in Big Lagoon from January 1957 to December 1957 is shown in Table 4.
Quantitative
Gill Netting: Gill netting in Big Lagoon was started on January 29,
1957 and continued until August 30, 1957. Both nets were fished overnight which
represents about eighteen hours fishing time per net. Each net was fished for
a total of 396 hours, or 792 hours for both nets.
A total of forty-four sets
was made. During this period twenty-seven steelhead trout and two cutthroat
trout were taken (Table 5). One salmonid per 27.30 hours fished was taken,
which represents 0.66 fish per set.
Creel Census: Two creel censuses were conducted during the course
of this study. The first was an intensive census conducted during the first
two weeks of the fishing season, April 27 through May 12, 1957. During this
period a total of 140 fishermen compiled a total of 469.3 hours fished, for
an average of 3.4 hours per man. The catch per man per hour was 0.12 fish.
The fish taken per man was 0.40 (Table 6). The second intensive census was
taken on the first two days of the fishing season, May 3 and 4, 1958. This
census showed 97 fishermen with a total of 166 hours spent fishing. This
represents 1.7 hours of fishing per man. The catch per man per hour was 0.14
fish. The fish taken per man was 0.24 (Table 7).
Thus the catch per unit of effort for both seasons was quite similar
and may be considered comparatively poor. A decline during the summer months
in the number of fishermen utilizing the lagoon has been noted during periodic
checks.
Stream Census: During the summer and fall of 1957 preliminary studies
were started on the methods to be used for population enumeration of natural
84
Table 8
Summary of First and Second Mark-Recovery Program
in Maple Creek, Summer-Fall, 1957.
First Program
Second Program
Marking:
Steelhead marked
1,220
1,118
90
54
1,213
946
95
152
Silver salmon sampled
62
112
Marks recovered
8
19
15,577
14,551
Upper limit of N
17,965
15,482
Lower limit of N
11,994
13,510
697
318
Upper limit of N
1,428
497
Lower limit of N
293
188
Silver salmon marked
Recovery:
Stelhadsmp
Marks recovered
Estimate of N:
Steelhead
Silver Salmon
85
Table 9
Daily Seine Samples of Trout and Salmon
from Maple Creek, April 7-21, 1958
stocks in Maple Creek. These techniques are part of the methods to be
employed in the determinations of the stream-survival rates of the marked
hatchery fish prior to their migration into the lagoon. During the first
summer only the mark-sample method was employed.
The first marking program began on July 24, 1957, and the first
recovery program started August 12. A second recovery program was started
and completed in September. It appeared that all of the fish captured were
steelhead of the 1+ age group and all of the silver salmon were fish of the
year (0+).
During this period of study, only one fish was recovered in an
area other than the one in which it was released. No other evidence of
migration was noted and it was felt that during this time of the year
(July-August) Tyke nets and downstream traps would have been ineffective.
The first population estimate for Maple Creek (July-August) showed
a steelhead population of 15,577, with the lower limit of the population
(N) at 11,994 and the upper limit of the population (N) at 17,965 fish.
The silver salmon population was found to be 697 individuals where N was
293 and N was 1428. The second population estimate was conducted during
September. The steelhead population was found to be 14,551 - a drop of 6.6
percent in about one month. N was 13,510 and N was 15,482. The silver
salmon population was 318 - a drop of 54.4 percent in about one month. N
was 188 and N was 497.(Table 8).
Between October 1957 and May 2, 1958, a total of 101,668 fish were
planted in Maple Creek. Of these, 44,756 were steelhead, 14,580 were cutthroats, and 42,332 were chinooks (Table 10). Salo (1958) found that in
March and April of 1958 sampling indicated a considerably larger population
of wild fish than in 1957, for out of 124 marked wild fish released, only
one was recovered in a sample of 103. The 1+ age group appeared to be the
87
Table 10
Hatchery Plants by Humboldt State College
into Maple Creek, 1958
88
significant group contributing to this increase. Although it was too
early to pick up specific mortality rates of the hatchery fish, Salo
(1958) showed that some very interesting estimates could be obtained
by using unmarked wild fish as the random variable in the probability
distribution and thus calculating the survival rates of the hatchery
fish. Using a wild fish/hatchery fish ratio of 68/115 (Table 9) and
assuming a wild fish population of 20,000, a survival rate of 75 percent
is obtained for the hatchery fish from the date of planting to the first
of May. If the wild fish population that was assumed to be 20,000 is in
fact greater, then the survival rate of the hatchery plants is correspondingly greater.
The above estimate would be invalid if the following four assumptions are not realized: (1) adequate mixing of hatchery fish and wild
fish, (2) sampling effort unbiased toward the areas of planting, (3) no
differential migration of wild or hatchery fish into the lagoon, and
(4) no gear selectivity.
89
DISCUSSION
AND
RECOMMENDATIONS
THE ENVIRONMENT OF THE LAGOON
The environment of Big Lagoon is truly dynamic and varied. It
can be classified as either marine, brackish, or fresh at any one time.
The presence of these three conditions are possible as a result of the
salt water influx caused by the breaching of the bar in conjunction with
the fresh water runoff from the tributaries.
During the summer months when the rainfall and resultant runoff
are at a minimum, and the wind agitation is low, the lagoon waters are
rather docile. The comparatively warm fresh water, which is less dense
than the saline waters, floats along the surface area. The cooler,
denser salt water is confined to the lower depths of the lagoon. Here
the available oxygen is in low concentrations. As the winter approaches
and rainfall and wind increase, the water level of the lagoon rises.
With this rise in water level there is also a rise in the ratio of fresh
water to salt water, even though some fresh water is lost through the
spit as described by Rowe and Royce (1953). The supply of oxygen in the
lower levels is replenished when the lagoon breaches.
The temperature strata are usually more stable in the lower depths,
where fluctuations in air temperatures have less effect. During the summer
months typical summer lacustrine and typical summer oceanographic conditions
are observed, i.e., with the warmer waters on top and the cooler waters on
the bottom. But during the winter months a meriomictic condition is observed,
in which the warmer water may be on the bottom and the cooler water on top
90
(Figure 36). The physics of this can be readily understood by relating
the temperature to the salinity gradient (Figure 19).
During those periods when the lagoon is open, a new supply of
salt water from the ocean enters the lagoon, replenishing it with oxygen
and nutrients. The extent to which the salt water encroaches upon the
lagoon is directly correlated with the height of the tide. Figure 30
shows this influx of salt water at Big Lagoon Station A on June 17, 1957.
It therefore follows that those organisms inhabiting the lagoon
must by necessity be very versatile in their adaptation, and capable of
withstanding sudden and extreme changes in chemical and physical factors.
POSSIBLE LIMITING FACTORS OF THE LAGOON ENVIRONMENT
ON THE PRODUCTION OF SALMONOIDS
Because of the complex life cycle of an anadromous fish, many
factors can influence the success or failure of the rearing program of
Big Lagoon.
The rate of oxygen consumption by fish varies greatly with the
size and species of the fish, and with temperature, pH, and dissolved
carbon dioxide. Therefore it is extremely difficult to define the lower
limits of dissolved oxygen necessary to support fish life, particularly
salmonoids. During the late summer and fall, before the first opening
of the lagoon, the lower depths are low in oxygen (Figure 31). This
represents a period of about three or four months during which the lower
depths of the lagoon may not be utilized for long periods of time by
salmonid fishes. This area constitutes a minor percentage of the lagoon
91
and is not significant. At no time during the course of this study
have the upper layers of the lagoon been low in oxygen.
No quantitative or qualitative determinations have been made
of the food materials in the lagoon, although great concentrations of
mysids (Neomysis mercedis) have been observed during the spring months.
It is not known whether there is an adequate food supply to support
large populations of fish throughout the year or whether there are any
definite plankton blooms. It was observed, however, that the populations
of flounders and sculpin in the lagoon were in extremely poor condition.
If these sculpin occupy the same ecological niche as salmonoids, then it
can be inferred that competition for food may be a significant factor in
Big Lagoon.
A study should be made of the amount and availability of food
for salmonid fishes. One approach could be through determining the
condition factor of the fish planted in the lagoon, during their lagoon
residence. Stomach analyses could be made. Analysis of the recovery
rates of spawned-out steelhead and their lagoon growth might also be
undertaken.
No predation studies, as such, were carried on. Possible
predators of salmonoids, as listed by Shapovalov and Taft (1954) and
Pritchard (1936), that were observed in the area are listed below.
The fishes found to be of some importance as predators were:
freshwater sculpins (Cottus asper and C. aleuticus), juvenile steelhead, juvenile silver salmon, and cutthroat trout. Although
three-spined sticklebacks (Gasterosteus aculeatus) were abundant, they cannot
be classified as predators. In the lagoon there were large populations
92
of staghorn sculpins (Leptocottus armatus) and starry flounders
(Platichthys stellatus), which are not listed as predators of salmonid
fishes, but may influence the overall ecological relationships of the
lagoon for salmonoids by affording excessive competition.
The following fish-eating birds were observed by the author
in the study area: western belted kingfisher (Megaceryle alcyon),
great blue heron (Ardea herodias), western grebe (Aechomphorus
occidentalis), redbreasted merganser (Mergus serrator), American
egret (Casmerodius albus egretta), pacific loon (Gavia arctica
pacifica), brown pelican (Pelecanus occidentalis californicus),
and double crested cormorant (Phalacrocorax auritus).
THE TIMING OF SALMON AND STEELHEAD RUNS
AS A POSSIBLE LIMITING FACTOR
Murphy and DeWitt (1951) described the fall run of spawning
chinook salmon in the Eel River as follows:
"In 1950 the spawning run of king salmon entered
the Eel River in August. The first fish were taken in
the sport fishery on August 12 and 15. From August
until October increasing numbers of salmon entered the
lower river. Some pushed upstream, apparently in response
to slight rises in the river induced by mild fall rains.
On October 6, 1950 the first king salmon appeared at
Benbow Dam on the South Fork of Eel River near Garberville.
Heavy rains occurred in the Eel basin the last week in
October. During and after these rains the king salmon
migrated rapidly upstream. During the week of October 29
to November 4, 4258 king salmon passed the Benbow Dam fishway.
From then until January 27, 1951, when the last king salmon
passed Benbow Dam, salmon were probably passing the lower
river, but because of high, muddy water practically none
were caught in the sport fishery."
93
Briggs (1953) found a similar situation in Prairie Creek,
Humboldt County, and Snyder (1981) described the fall run in the
Klamath River as beginning about one month earlier. It can be inferred
from these reports that this pattern holds true for spawning runs all
along the north coast of California. Since the lagoon generally does
not open until mid-December, a definite problem exists as to the
adaptability of king salmon to Big Lagoon. If a successful plant does
return to the lagoon in the early fall, they may not be able to enter
the lagoon until the first opening in mid-December. This may be the
reason that, at the present time, there is no natural run of kings in
Big Lagoon.
There are five possible solutions to this problem: (1) Artificial opening of the lagoon, which can be accomplished when the lagoon
depth is 28 feet or greater (verbal report, Richard Warren, Resident
Engineer, California Division of Highways, 1957); but this situation
is generally not encountered until around late November or early
December. (2) Installation of tidal gates and/or flume with adequate
passage in and out for fish. (3) Capture of the fish in the ocean,
when and if they school outside the lagoon, and taking the eggs on
the spot for subsequent hatchery rearing. (4) Development and
establishment of a late spawning strain of kings. (5) Eggs obtained
from other hatcheries and reared in the Humboldt State College hatchery
for release in Big Lagoon may contribute sufficiently to the ocean
fishery to warrant the continuance of such a program without means for
taking eggs from the returning fish that are unable to enter the lagoon.
Shapovalov and Taft (1954) and Murphy and DeWitt (1951) have
described the silver salmon and steelhead trout spawning migrations
9;4
that occur in Waddell Creek and the Eel River as being in the late fall
and early winter, with the peak months around November and December.
Briggs (1953) found a similar situation at Prairie Creek. Considering
this later spawning time, as compared to king salmon, and also considering the time of the first opening of the lagoon, conditions are
such as to lend to the management of these two species.
Captain Walter Gray, Chief of Patrol, Department of Fish and
Game, Eureka, California, has stated that in aerial flights he has
observed schools of salmonoid fishes off the bar at Big Lagoon waiting
for it to open. If this is so, and if these fish are destined for the
lagoon, the fact that a bar extends across it does not hinder their
homing instinct.
Observation in the past has shown that after the lagoon opens
and provides access to Maple Creek, little time is spent before the
first fish are seen on the spawning grounds. During the fall of 1956,
fourteen days after the lagoon had opened for the first time, spawnedout steelhead carcasses were found in Maple Creek. Ripe steelhead were
also taken in the lagoon as late as April 1957.
CONDITIONS IN THE LAGOON AT THE TIME OF DOWNSTREAM MIGRATION
In typical streams along the north coast, access to the sea is
generally always afforded downstream migrants. In Big Lagoon the situation
facing downstream migrants is much different.
King Salmon
Murphy and DeWitt (1951) have noted that the months of July,
95
August, and September are the most active for downstream migrants in
the Eel River. Snyder (1931) also has found late summer and early fall
to be the time most favored for downstream migrants. Both of these
authors have stated that many of these migrants appear to favor estuarine
existence for varying periods of time before migrating to the sea. This
estuarine life was of greater duration in the Klamath than in the Eel
River. In their report, Murphy and DeWitt (1951) state that the most
desirable size to plant salmon in the Eel River would be at least 3.5
inches fork length. This is the average size of the downstream migrants
in the wild stage. In the State of Washington, downstream migration of
chinooks seems to take place much earlier. Regenthal (1954) and Wendler
and Deschamps (1954) found that in the Snohomish and Wynooche Rivers the
major concentrations of chinooks migrated seaward during the months of
April and Mag.
If the downstream migrant chinooks from Maple Creek reach the
lagoon during the months June-August or April-May, dependent upon the
strain, they will be faced with a typical summer-type lagoon situation.
Once in the lagoon they will not be able to escape to the sea until
December. But during this time in the lagoon they will be able to indulge
in a pseudo-estuarian existence. By distributing themselves throughout
different parts of the lagoon, the fish may find that salinity which is
best suited to their needs for conversion to salt water.
Silver Salmon and Steelhead
In Waddell Creek, Shapovalov and Taft (1954) found that 95 percent of all downstream migrant silver salmon had undergone their seaward
migration during the nine-week period from April 8 to June 9. They also
96
state that fish in the Eel River drainage and Beaver Creek, a tributary
of the Klamath River 160 miles above the mouth, undergo migration during
approximately the same period. In the State of Washington the time of
migration for silver salmon appears to be about the same time as in
California, with the peak of the runs occurring about a week or two
later (Regenthal, 1954, and Wendler and Deschamps, 1954).
As in the case of king salmon, this means that the downstream
migrant silver salmon and steelhead will not be able to escape to the
sea until the first opening of the lagoon in December.
Young steelhead trout seem to have two periods of downstream
migration: (l) in the late fall, and (2) in the late spring and early
summer, with May being the most active month (Shapovalov and Taft, 1954).
The early fall migrants will have only a short wait until the
lagoon opens. During this time these fish will probably not be found
in the depths of the lagoon where the water is more saline and is low
in dissolved oxygen. In the past, sport catches in the fall have revealed
the best catches of young steelhead were along the northeast shore of the
lagoon, in rather shallow areas. This implies one of three things, or a
combination thereof: (l) the low concentrations of dissolved oxygen
keeps the fish out of the depths, (2) their osmo-regulation is such as
to prevent them from entering the waters of high salinity, or (3) food
organisms attract them to the area along the northeast shore.
The summer downstream migrants are faced with a totally different
situation. These fish must remain in the lagoon through the summer and
fall, and then pass oft to the ocean with the late migrants in December.
97
VARIATIONS IN THE ANNUAL CYCLE OF BIG LAGOON
AND THE POSSIBILITY OF PREDICTING WATER CONDITIONS
Numerous physical factors affect the annual cycle and water
compositon of Big Lagoon. If there are no major physical changes, then
it can be expected that the seasonal conditions would be similar from
year to year. Stability of this nature would be very helpful to the
fisheries biologist for it would be possible to estimate the conditions
in the lagoon by taking restricted spot checks. This method can be
employed during gill netting programs when it is desirable to know the
general conditions throughout the lagoon. It was actually found possible
that by taking a spot sample at Station C, the chlorinity at any other
place in the lagoon at the same depth of the sample could be predicted.
The accuracy of this method was found to be ±1.50 parts per thousand.
By taking samples every two feet in the lagoon at Station C, the general
chlorinity patterns throughout the entire lagoon can be determined.
RECOMMENDATIONS CONCERNING A SPILLWAY AND/OR TIDAL GATES
The possible need for a spillway at Big Lagoon was one of the
factors instrumental in prompting the original plans for the Big Lagoon
project. Concern over necessity for a spillway was expressed primarily
by sportsmen's organizations in the Humboldt County area. They felt
that the most significant contribution to the potential of the Big
Lagoon fisheries could be made by installing a means for fish to migrate
in and out of the lagoon. As this is an engineering concern, the problems of constructing a spillway were not investigated. However, observations over the last two years lead to the following recommendations:
98
(1) Α simple spillway to accommodate overflow in order to prevent breaching
would be entirely impractical. Without interchange, the saline waters of
the lagoon would become very low in oxygen, high in H2S, and a general
stagnant condition would exist for a number of years until complete loss
of the entrapped salt water had taken place. The only water to flow out
to sea through the spillway would be the upper, less dense layers of the
lagoon, which would be the freshwater runoff from Maple Creek. (2) In
a very limited way, access to the lagoon could be afforded spawning runs
by artificially opening the lagoon. This can be accomplished when the
lagoon reaches about 28 feet or more in depth. Α bulldozer or crane is
usually employed in this operation, but on occasion when the lagoon is
within a foot or two of opening, it can be opened by shovel crews. (3)
Probably the best way to solve this problem, but by far the most expensive, would be to build a flume connecting the ocean with the lagoon.
This flume should be equipped with valves or tidal gates to control the
inflow and outflow of the lagoon waters. It would be impractical to
build this flume into the north end of the bar for two reasons: (a)
the bar is very unstable here, and (b) the lagoon would be unable to
open naturally, thus accelerating the sedimentation fill. The ideal
place to locate the flume would be in the middle or the south end of
the spit, wherever the lagoon strand is most stable. This flume could
be placed down in the bar and water could flow into the ocean or into
the lagoon. In this way, by controlling the valves, fish could pass in
and out of the lagoon when the bar was closed. When desirable, the
Lagoon could be allowed to fill and open naturally. The flume would
serve a twofold purpose by affording passage to migrating fish, and
aid in maintaining more stable water levels in the lagoon for boating.
99
SUMM ARY
1. In the Fall of 1956 Humboldt State College, the Wildlife
Conservation Board of California, and the California Department of
Fish and Game entered into contract to study the possibilities of
using the Northern California Coastal Lagoons as supplemental rearing
areas for anadromous fishes such as salmon and trout. Because of the
great economic importance and present critical situation of the king
salmon (Oncorhynchus tshawytscha), and the importance of silver salmon
(Oncorhynchus kisutch) and steelhead trout (Salmo gairdneri gairdneri),
the project concentrated on these species.
2. Since the success of the lagoons as rearing areas is directly
associated with the environment of the lagoon, it was obvious that a
study of the physical and chemical characteristics of the lagoon would
constitute the. initial phase of the study. It is with this phase of
the project that this paper is concerned. The studies started in the
Fall of 1956 and were carried on until the Spring of 1958.
3. The methods, materials, and sources of error are described.
4. Successive elevations and depressions of land masses along the
North Coast, coupled with fluctuating sea levels, led to the formation
of small bays along the North Coastal area. Wind-driven, along-shore
currents were the significant forces in forming the bars which made these
small bays into lagoons. The southeasterly winds of the winter caused
a northerly-flowing along-shore current while during the summer months
the prevailing northwesterly winds caused a southerly along-shore current.
5. Big Lagoon is situated 24 miles north of Arcata, California, on
Highway 101. It is the southernmost of a series of four lagoons located
100
within eight miles of each other. The lagoon is about 3.5 miles long
and 1.3 miles at the widest point. When the lagoon is 25 feet, it covers
an area of 1470 surface acres. To the west the lagoon is separated from
the ocean by a sand bar about 3.2 miles long which averages 700 feet wide
at mean low tide.
6. The Big Lagoon bar is not stable, but is subject to opening and
closing during certain times of the year. These openings occur during
the winter rainy season. With heavy run-off the lagoon fills with water.
As the lagoon approaches its maximum level, the sand particles of the
bar become buoyant in the surrounding water medium. As seepage through
the bar from the lagoon to the ocean takes place, the particles of sand
become so buoyed that the bar breaches and the lagoon evacuates in dramatic fashion. Then natural forces repair the breach for a repetition
of the cycle.
7. Three streams, Tom Creek, Maple Creek, and Pitcher Creek supply
virtually all of the water entering the lagoon and furnish all of the
spawning areas available to salmonoids.
8. The total rainfall for the period October 1, 1956 to September
30, 1957 was 66.2 inches. The closest available wind data was from
Eureka, California. The 44-year average hourly wind velocity was 7.3
miles per hour. The summer winds were dominantly northerly and in the
winter the winds were southerly. The presence of fog in the summer
months was a definite limiting factor in affecting the amount of evaporation. The maximum and minimum air temperatures recorded for the 19561957 period were 83 and 22 degrees Fahrenheit.
9. The salinity patterns in Big Lagoon were found to be extremely
variable. Even while the lagoon was closed, day to day differences in
101
stratification were evident. Chlorinities on the bottom were always
found to be greater than at the surface. During the summer of 1957 the
highest chlorinity recorded was 17.40 0/00 at a depth of 20 feet. The
lowest chlorinity recorded in the lagoon was 0.05 °/oo. While the lagoon
was open to the sea, physical forces of mixing were found to be most
significant. It was during this period that replenishment of dissolved
nutrients took place. Oxygen was also replenished in the lower layers
during these periods. After the last closing of the bar, oxygens were
found to progressively decrease with time in the lower layers, resulting
in an oxygen-deficient area in the bottom of the lagoon. The oxygen in
the upper layers of the lagoon was replenished throughout the year by
wind agitation, but in the lower layers no replacement of oxygen was
evident except when the lagoon was open to the sea. Two distinctive
temperature patterns were evident in the lagoon: (1) a winter pattern
when the warmest waters were on the bottom, and (2) a summer pattern
when the coolest waters were on the bottom. The coldest temperature
recorded in the lagoon was 5.6 degrees centigrade while the warmest
was 23.0 degrees centigrade.
10. Gill netting in Big Lagoon was started on January 29, 1957 and
continued until August 30, 1957. A total of forty-four sets was made.
During this period 27 steelhead and 2 cutthroat trout were taken.
11. Two creel censuses were conducted during the course of this
study. The average fish taken per man per hour was 0.13.
12. During the summer and fall of 1957, preliminary studies were
started on the methods to be used for population enumeration of natural
stocks in Maple Creek. The first marking program began on July 24, 1957
102
and an estimated population of 15,577 steelhead and 697 silver salmon
was obtained. The second population estimate was conducted during
September. The steelhead population was found to be 14,551 - a drop
of 6.6 percent and the silver salmon population was 318 - a drop of
54.4 percent.
13. Between October 1957 and Hay 1958, a total of 101,668 fish
from Humboldt State College Fish Hatchery was planted in Maple Creek.
14. Possible predatory fishes and birds of Big Lagoon are listed.
15. Because the lagoon bar is not open during the time of king
salmon spawning runs, a definite problem exists as to the feasibility
of establishing a chinook run in Big Lagoon. The periods when the
Big Lagoon bar is open are during the time of the steelhead and silver
salmon spawning migration.
16. Steelhead and silver salmon juveniles migrating downstream
after April generally are unable to reach the ocean. They must remain
in the lagoon until the first opening, usually in late December.
17. It was found that by taking spot samples, chlorinities
throughout the lagoon could be predicted to i1.50 0/00.
18. Because of the problems confronting salmonoids is entering
and leaving the lagoon, it is probable that some means may have to be
arranged for to give controlled access to and from the ocean.
Recommendations for solution are listed.
103
LITERATURE CITED AND ADDITIONAL REFERENCES
ANDERSON, W.W. et al
Physical, oceanographic, biological, and chemical
1956.
data - South Atlantic coast of the United States.
Special Scientific Report - Fisheries, No. 178: 160.
ΒΙGELOW, H.Β. and W.T. EDMONDSON
Wind waves at sea; breakers and surf.
1947.
U.S. Hydrographic Office, No. 602.
BRIGGS, J.C.
1953.
CHAPMAN, D.G.
1948.
The behavior and reproduction of salmonid fishes
in a small coastal stream.
Calif. Div. Fish. and Game, Fish. Bull. No. 34: 59.
A mathematical study of confidence limits of salmon
populations calculated from sample tag ratios.
Bull. No. 2. Inter. Pac. Salmon Fish. Comm.
CLOPPER, C.J. and E.S. PEARSON
The use of confidence or fiducial limits illustrated
1943.
in the case of the binomial.
Biometrika, 5 (26) Cambridge: 404.
CUMMINGS, N.W.
1950.
DEANGELIS, R.
1950.
Minimum evaporation from water surfaces.
Am. Geophys. Un., Trans. Vol. 31: 757-762.
La sistemazione idraulica e les trasformazione
fondiaria dei comprensori lagunari in Grecia.
Boll. Pesca, Pisciculture, Idrobiol. 5, n.s., fasc.
l: 128-154.
1952a.
Difesa ed increminto delle pesca e delle pisciculture
nelle lagune costiere.
Boll. Pesca, anno 28 (n.s. anno 7), No. 3, May-June
1952: 4-5.
1952b.
Lagune, velli e boniface.
Ibid., No. 4, July-August 1952: 4-7.
1955.
L' incremento delle pesca nella laguna di Varano.
Roll. Pesca, anno 31 (n.s. anno 10) No. 3, May-June
1955: 5-8.
104
ELLIS, C.H.
1957.
FAGANELLI,
1951.
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10
APPENDIX
This Appendix lists all observed chemical
data obtained from Big Lagoon during the
study period.
111
Observed Data, Big Lagoon - October 27, 1956
112
Observed Data, Big Lagoon - November 25, 1956
113
Observed Data, Big Lagoon - November 16, 1956
114
Observed Data, Big Lagoon - December 31, 1956
135
Observed Data, Big Lagoon - January 3, 1957
116
Observed Data, Big Lagoon - February 19, 1957
117
Observed Data, Big Lagoon - Αρril 9, 1957
118
Οbseτνed Data, Big Lagoon - June 17, 1957
119
June 17, 1957 (Continued)
120
Observed Data, Big Lagoon - July 1, 1957
121
July 1, 1957 (Continued)
122
Observed Data, Big Lagoon - July 16, 195?
123
July 16, 1957 (Continued)
1214
Observed Data, Big Lagoon - August 7, 1957
125
August 7, 1957 (Continued.)
126
Observed Data, Big Lagoon - August 8, 1957
August 8, 1957 (Continued)
128
Observed Data, Big Lagoon - August 10, 1958
129
August 10, 1958 (Continued)
130
Observed Data, Big Lagoon
-
October
13, 1957
131
October 13, 1957 (Continued)
132
Observed, Big Lagoon - Νovember 26, 1957
133
November 26, 1957
(Continued)
131
November 26, 1957
(Continued)
λ35
Observed Data, Big Lagoon - April 19, 1958
136
April 19, 1958 (Continued)
April 19, 1958 (Continued)