Name of author
Date of birth
Place of birth
Universities attended
University of Wisconsin
University of Oregon
Degrees Awarded
Vita
Thomas Aaron Ebert
July 10$ 1938
Appleton, Wisconsin
Dates
September 1956 to
June 1961
September 1961 to
June 1966
i
B, S" University of Wisconsin, June 1961
M, St, University of Oregon, June 1963
Professional experience
Project Assistant, University of Wisconsin 6~61 to 8-61
Teaching Assistant. University of Oregon 1961 to 1963
Research Assistant, University of Oregon 1963 to 1966
Instructor, Division of Continuing Education, Eugene, Oregon
1963 to 1966
Publications
Ebert, T. At 1965.
sea urchins,
A technique for "h~ inrividual marking of
Ecology 46(1/2):193-194.
Ebert, T. At 1965. Test diameter changes in natural populations
of the sea urchin, Stponau[oaentrotus purpuratus. Bull.
EcoL Soc. Am. 46(4) :166" '"
T
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LOCAL V~~IATIONS OF GRO~tTH, FEEDING,
REGENERATION AND SIZE STRUCTURE IN A NATURA~
POPULATION OF THE SEA URCHIN, STRONGnOCENTROTUS
PURPlJRATUS (STIMPSON)
by
THOl1AS A.4..RON EBERT
A THESIS
Presented to the Department of Biology and
the Graduate School of the University of Oregon in
partial fulfillment of the requirements of the degree of
Doctor of Philosophy
June 1966
,.
APPROVED
{;t'S, w. ~~~.(,L
Peter Wo Frank
Adviser for the Thesis
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ACKNmiLEDr.MENTS
All photographs in this study, except the aerial uhoto~ranh
of Sunset Bay (Fig. 1), ~-1ere taken by I1r. John H. Evans.
The growth analysis in Table 4 was done at the Universitv of
Oregon Statistical Laboratory and Computing Center on an I.B.M.
1620 computer. Laboratory personal were most patient and heluful
during the writing of the program and its running.
I would like to thank Dr. Peter W. Frank for his help durin~
the past four years. Many parts of this study are direct or in-
direct results of his sug~estions.
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To Timmy and Chris, two ~rchins
of a different color •
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TABLE OF CONTENTS
INTRODUCTION . • • 1
AREAS AND METHODS. 4
DISCUSSION
LITERATURE CITED • .
Algae held by samples
of urchins • • • • • • • • • • • • • • • • • 122
33
17
17
27
99
89
. . . . 34
39
57
58
62
65
81
88
Species list of algae
from Sunset Bay. • • •••••••••• 104
Summary of growth
information on echinoids • • • • • • • • • • 107
Effect of marking on
growth of the test • • • • • • • • • • • • • 130
Inorganic components of
the gut contents • • • • • • • • • • • • • • 117
RESULTS. • • • • •
Growth and Repair of Spines • • • • • •
Growth Lines in the Plates of the Test.
Summary of Results on the Investigation
of the Spine and Plate Growth • . • •
Description of the Size Distribution of
Urchins at Sunset Bay • • • • • • • • •
Examination of Growth Rates in the Three
Major Study Areas • • • • • • • •
Effects of Spine Breakage on Growth • . •
Breakage of Spines in the Field • . • • .
Complete Removal of Spines under Field
Conditions. • • • • • • • •
Amounts of Food Eaten per Day •
Decrease in Gut Contents with
Gonad Growth. . • • • • • •
Summary of Investigation of Size
and Growth. • • • •
Appendix I
Appendix II
Appendix III
Appendix IV
Appendix V
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INTRODUCTION
I here salute the echinode~s as a
noble group especially designed to puzzle
the zoologist o
Libbie Ho Hyman i 1955
Although echinoid populations have been much exploited in physi-
ology and embryology,they have been relatively neglected by ecologistso
Few studies of growth rates of urchins have been conducted, and those
in the literature often lack critical information on local variations
in growtho These will be examined in detail in the Discussion o
Probably the major reason critical information on growth has not been
gathered for urchins in the field has been the lack of an adequate
method of marking individuals o Methods cited in the literature are
elastic bands around the test (Moore 1935); nylon line or brass wire
wrapped around the test i small squares of rubber balloon placed on the
spine tips, and plastic=covered wire or brass wire threaded through
holes drilled in spines (Sinclair 1959); and plastic discs on stain-
less steel wire pushed through the test (McPherson 1965)0 All of these
methods are useful for short time periods only 0 The development of a
suitable marking procedure was probably one of the major factors in
making this study possible o
The urchin examined here, StrongyZocentrotus purpuratus (Stimpson).
is a regular echinoid of the family Strongylocentrotidae,distinguished
from other c~on littoral members of the genus on the eastern Pacific
coast (So drbbaahiensis and So franciscanus) by the slight difference
between primary and secondary spines (this at once distinguishes it
from So franaisaanus in which primary spines are much larger than
2secondary spines) and at least eight pore pairs on typical aboral
ambulacral plates (this separates it from S, drVbachiensis)o The
purple urchin, according to Ricketts and Calvin (1962), ranges from
Alaska to Cedros Island, Baja California; however, Boolootian (personal
communication 1964) states that purple urchins north of Puget Sound
probably are So echinoides. The urchin examined in this study occurs
along the south central Oregon coast and is, without doubt, S. purpur-
atus.
The purple urchin is mainly an herbivore using algae as its chief
food source. To an extent it is also an opportunistic feedero It
either grazes on attached algae or catches floating debris o Urchins
may move to large pieces of food such as dead fish o The sexes are
separate; spawning is during February and Harch (Ricketts and Calvin
1962), or no definite season may exist, with some individuals able to
spawn at any season, and possibly individuals being able to spawn more
than once during the year (Giese ~~o 1959)0 In rocky areas, the animals
may be very common and reach densities of over lOO/m2• In the areas
discussed here, urchins appear to be the major herbivore and~therefore,
of considerable importance with respect to energy flow through the
ecosystem.
The present study examines local growth variation in a population
of urchins at Sunset Bay, Oregon o Differences in the rates of growth
as well as differences in size structure are shown. Some of the
conditions associated with different growth rates are examined. This,
to be sure, is in terms of correlation rather than causation, and
definite conclusions concerning cause can not be made; however, a
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reasonable picture of growth and growth regulation can be constructed.
Methods of study of urchin populations are developed which are applic-
able to the study of other echinoids and possibly to other populations.
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4
AREAS AND METHODS
The area studied was the south side of Sunset Bay, Oregon. lat.
N. 430 20', near the city of Coos Bay, Oregon. The south side of the
bay is formed of tipped beds of sandstone dipping sharply to the east
and striking north and south. Differential weathering has produced
a series of ridges, flat areas and channels seaward and a relatively
flat area shoreward with a boulder field at the north end (Fig. I).
The flat area south of the boulder field is where growth of the turban
snail TeguZa was studied by Frank (1965). The urchin beds investigated
are shown in Fig. 2. Three locations were of major interest and are
referred to as: PosteZsia zone, high eel grass area, and boulder
field. Relatively, the eel grass area is the highest intertidally,
the PosteZsia zone next and the boulder field lowest. A species list
of the more common algae in each location is given in Appendix I.
The general procedure for the study of growth rates was to measure
and mark animals in the three areas and to measure these again at later
dates. The first marking method consisted of slipping pieces of
spaghetti tubing over the tips of spines (suggested by Dr. Cadet Hand
ca. 1960). Using this technique J14 animals were marked at Sunset Bay
on 8 December 1962. On 22 January 1963 j three animals were recovered.
The marked spines apparently deteriorated around the mcrk and could
be easily broken. The method was discarded. A second unsuccessful
method which was field tested used plastic dart tags manufactured by
the Floy Tag &Manufacturing Company, Seattle, Washington. The comp-
any shortened a standard dart tag used for fish and six of these were
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5Figure 1
Aerial photograph of the south side of Sunset Bay showing
general topography 0 The outlined area includes all regions of
this study and is shown in a vertical projection in Fig. 20
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7a:r~:a~ where animals were studied 0
Figure :2
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Name used in text
Eel ~rass area
High area above and north of Postelsia zone
South and below Postelsia zone
North and below Postelsia zone
Boulder field
West and north of eel grass area
Postelsia zone
F
Aerial photograph of the south side of Sunset Bay showing the
A
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B
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Lener
5 T mm
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9
planted at Sunset Bay in animals with test diameters of 2.1 to 7.6 cm.
The date of marking was 26 January 1964. On 23 February 1964,a11
marked animals had disappeared. The marking method which proved to be
successful was developed during the summer of 1963. It consisted of
inserting 0.025 mm diameter ( 4~lb 0 test) nylon monofilament line
through two holes in the test i marking the line with colored pieces
of vinyl tubing, and fastening the ends of the line with a square-
knot and a drop of Dekophane (a methacrylate glue) or Duco cement. A
piece of the vinyl tubing was slipped over the knot. Insertion of the
line was accomplished with a 22=guage~ 2-inch hypodermic needle mount-
ed on a shaft and used in a high speed drill. The methodfas reported
(Ebert 1965») used a needle with a side hole in the base to allow the
line to be threaded after the holes were drilled in the test. This
was discarded in the summer of 1964 when it was found that the mono-
filament could simply be inserted into the tip of the needle after
drilling through the test~ pushed down as far as possible and the
needle pulled out. Threading in this manner required no groove in the
shaft holding the needle or hole in the base.
There were apparently no serious effects of marking. The holes
in the test sometimes healed and held the line securely. Often, how-
ever, the holes remained open and the line could be freely moved even
after a year in the field. A small calcareous deposit filled with
granular pigmented (echinochrome) material was often formed on the in-
side of the test around the monofilament line. The most serious
consequence of marking was the apparent decrease in growth rate of the
marked &ubulacrum. This decreased the precision of estimating the
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diameter and also yielded a slightly lower growth rate estimate for
the entire animalo The increase in standard error is shown in Appen-
dix V along with changes in size of representative animals which show
the slower growth of the marked ambulacrumo
During the summer of 1963~ 131 animals were marked and returned
to a tide pool in the eel grass area o In 1964~ only six of these
marked urchins were recovered o It was found in Septa~ber 1963 that
an animal could chew through the monofiiament line if the loop was
long enough to reach its mouth o This probably accounts for the poor
recovery of animals marked in 19630 In the summer of 1964 i 500
animals were marked i using smaller loops; these were distributed
among the Postelsia zone i the eel grass area and the boulder field.
Samples of animals were measured from the three areas in December
1964, April 1965 and July 1965, approximately one year after the ori-
ginal marking. Additional animals were marked and placed in the three
areas in July 19650 Samples were again measured in November 1965
and March 1966. Measurements of test diameter were made with knife-
edged vernier caliperso Five measurements were made per animal from
the center of each ambulacrum to the center of the opposite inter-
ambulacrum. Standard errors of such measurements are given in Appendix
Vo A comparison of measurements of animals before and after cleaning
in NaDel is given in Table 1.
l~en it became apparent that there were differences in growth
rates among animals from the three areas, a search was begun to
determine some of the factors responsible for these differences.
11
Table 1
Check on the accuracy of measurement of test diameter of livin~
urchins. Animals were collected at Sunset Bay 25 June 1964, ffi, rked
and measured, killed and bleached in NaOel and again measured. ~fRans
are from five measurements and are in centimeters.
11easured al: ve
l1ean + SE
5.19 0.014
5.38 0.006
5.~ 6 0.023
5.15 0.007
4.98 0.017
5.08 0.013
4.83 0.008
5.74 0.015
Measured after c1eanino,
Mean + SE
5.18 0.011
5.37 0.008
5.53 O. OOl~
5.15 0.008
4.99 0.005
5.07 0.009
4.81 0.001
5.72 0.009
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Because the areas are very close togetherJthe assessment of factors
influencing growth, to an extent, is simplified. Such variables as
temperature, salinity, oxygen tension, turbidity, pH and concentrat-
ions of trace ions were assumed to be approximately the same for all
the animals studied. Because of differences in tidal levels there are,
of "course, local changes in these variables; but, because of the
proxL~ity of the areas, these factors were ignored.
Environmental components which were investigated were wave a~pos-
ure and food.
Population density was not measured in Sunset Bay because of the
difficulties caused by the highly irregular relief. Visually, the
three major areas seemed to have about the same numbers of animals.
Typically, unless there is actual physical contact, density of a
population is assumed to simply indicate differences in the amounts
of food gathered. Attempting actually to measure the food intake
of the urchins eliminated this problem.
Food gathered per day was estimated by feeding pieces of tattooed
algae to samples of animals in each of the three areas and collecting
the animals 24 hours later, dissecting out the gut and determining
the amount between the mcuth and the tat toed piece of algae.
Samples of 10 animals from each area were collected eight times
during the period September 1964 to October 1965. ~fuen collected,
the animals were killed and fixed in the field with an injection of
100% formalin. The amount used varied with the size of the animal
but ranged between 3 and 7cc. This amount of formalin was necessary
< I 13
to prevent autolysis of the stomach (llsmall intestine" of Hyman
1955)0 Animals were preserved in 5% formalin in sea water until ready
for dissectiono They were then washed in fresh water for 24 hours g
damp dried and measuredo Animals were dissected in the following
manner 0 A cut was made around the peristome 9 and the membrane re-
moved 0 A strong pair of forceps was inserted around an ambulacrum
(one arm of the forceps inserted on the inside and one on the outside
of the test)o Care was taken to avoid rupturing the guto A small
piece of test was broken out 9 and the procedure repeated for another
arnbulacrum o After five slots were completed, one in each ambulacrum,
a small spatula was used to break the mesentaries holding the gut
and the gonads to the interarnbulacral areas o As areas of inter-
ambulacrum were freed,the plates were removed by breaking them off
with a strong forcepso After reaching the ambitus,it was usually
possible to free the gut and gonads from the test without further
breaking of plateso The freed mass was placed~ oral side dowu 0 into
a white dissecting trayo The gonads were separated from the gut for
weighing 0 The small intestine was disarticulated from the large
intestine and the entire digestive tract was spread out o The esopha-
gus and lantern were placed with the spines and pieces of test o
Small sections of gut were cut off~ starting at the junction of
intestine and esophaguso These were placed in a water-filled
Syracuse dish 9 opened,and the contents examined for the presence
of the tattooed algaeo l1hen the marked Hedophyllum was found it
was removed and discarded, and the contents between it and the mouth
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14
were placed in a 50 ml beaker. Gut contents after the tattooed algae
were weighed separatelyo The gut wall was dried with the test plates
and spineso Beakers were placed in a drying oven at 110-1150 C for
at least 24 hours, cooled in a CaCl2 desiccator and weighed to the
nearest 10 mg on a Mettler balance. After weighing, the dried gonads
were discarded. The tests and gut contents were treated with 5%
sodium hypochlorite (commercial bleach) to remove organic materialo
Usually at least two treatments with NaOCl were required o After
treatment the samples were washed and again dried and weighed o Gut
content samples were then treated with HCl to remove CaC03, washed,
dried and again weighed. The information gathered from each animal
included: diameter and height (t1 'ree measurements of each with
vernier calipers to the nearest 0.1 mm), gonad dry weight, total or-
ganic weight other than gonad weight, calcite weight and weight of
food, CaC03 and silicious sand before and after the marked algae.
Physical abrasion in each area was estimated by an examination
of spine breaks and tubercle morphology. A sample of animals was
collected in August 1964 from the three locations and, after cleaning
the animals in NaOel, washing and drying, a spine sample was impreg-
nated with a mixture of 22 parts terpineol and 1 part methyl salicy-
late as suggested by Deutler (1926; originally from Becher 1914).
Impregnation was ~ilitated by placing spines in the oil mixture
under a vacuum. Spines were viewed with transmitted light under a
compound microscope. Breaks were measured with an ocular micrometer.
More detailed work with internal structure of the spines was done
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15
by making thin mid-sagittal sections in essentially the manner of
Carpenter (1847, 1870) and Deutler (1926)0 After bleaching in NaDCl,
washing and drying~ the spines were dipped in xylene~ placed on a
slide and covered with Canada balsam o They were then heated on an
electric hot-plate to boil away the xylene and cooled o When hard, the
preparations were suitable for making thin sections by grinding on a
glass plate with #220 followed by #600 carborundum grinding compoundo
Water was used as the liquid medium for grindingo The slide was
tilted during grinding to insure production of a median sectiono
After grinding one side& the slide was returned to the hot-plate, the
balsam remelted and the spine turned over, recooled and grinding com-
pletedo The preparation was cleaned with xylene before a cover slip
was added 0
Before June 1963, organic material was not removed from the spines
before grindingo This caused the spines to become extremely brittle,
and most of them fractured during the grinding process o Removal of
as much organic material as possible with NaGCl facilitated the hand-
ling of spines with a minimum of damageo NaDCl was used by Swan
(1952) and is essentially the "Eau de Javelle" of Deutler (1926)0
Sections were made of test plates to examine the "growth zones"
as a possible means of determining age o Separation of the plates
required first boiling the tests in watero These were then disarticu-
lated and the plates dried and mounted on slides in approximately the
same manner as the spines o Rough grinding was greatly facilitated
by the use of a Dremel Mota-tool with a small drum-sander bito
Photographs were produced from the finished slides simply by
placing them in the negative holder of a photographic enlarger and
16
projecting onto high=contrast paper. All slides were projected with
the same magnification so direct measurements could be taken from the
negative prints.
Certain studies were carried out in the laboratoryo A circulating
sea water system was constructed in an 110C controlled temperature
room. The basic plan of construction followed the system built at the
University of California at Riverside by Lars Ho Carpelan (Strong
1962). Experiments on regeneration of spines and growth of animals
were carried out using this systemo
Work during the summers of 1963, 1964 and 1965 was based at the
Oregon Institute of Marine Biology at Charlestono The Institute is
3 miles north of Sunset Bayo
Further detailed explanations of techniques will be given where
appropriate in the results o
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RESULTS
The results will be divided into two major parts~ a section on
growth of spines and plates and deposition of pigments, and a second
section describing size distributions of animals at Sunset Bay,
growth rates of animals from three major areas of study (the PosteZsia
zone, the eel grass area and the boulder field) and some factors which
may be important in determining differences in growth rates.
Growth and Repair of Spines
The calcareous portions of urchins are internal, of porous con-
struction and filled with living organic material (Hyman 1955). The
microscopic structure of spines was apparently first examined by
Valentin (1842) and that of the test apparently first by Lov~n (1874).
Spine sections have been 'described for many species of urchins by
various authors (Carpenter 1847, 1870; Mackintosh 1879, 1883a and b;
V /'1/ ""Krizenicky 1917; Deutler 1926, H.ortensen 1928-1951), but the "rings"
or "cycles of wedges" which appear in cross section (Figs. 3 and 4)
have not been properly interpreted. Carpenter (1847, 1870) and Swan
(1952) have suggested that these cycles may be formed like the annual
growth layers in woody perennial plants. Deutler (1926) calls them
"Wachstumzonen" and suggests periodic formation. Borig (1933) recog-
nized that cycles ended at sharp discontinuities, but still concluded
that "cycles" were formed periodicly. He felt that after breaking,
the spine would not regenerate a new tip until the next "~lachstumperiode"
when a new tip and a new cycle would be formed. Cycles would be added
even though no break had occurred.
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18
Figure :J
Cross section of a spine of StrongyZoaentrotus purpuratus
showing 4 cycles of wedges (large calcite crystals) and fine
ct'ystalline me:sllwork with dense pigmentation o The central area
with wid~ meshes probably indicates that the ~pine has been to-
tally regenerated,
Figure l
Cross section of SQ purpuratus spine showing 10 cycles of
wedges 0
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Examination of several hundred longitudinal sections of S,
pu:z>puroius spines ~ during the summer of 1963~ led to the hypothesis
that cycle formation was the result of breakage and regeneration. This
was proposed because: spines always have a cycle of wedges on the
outside and if the cycles were formed only at certain periods during
the year 3 at some time one would expect to find the fine crystalline
meshwork on the outside (this is never the case); and in longitudinal
section~ cycles are always distally terminated at a sharp discontin-
uity lJl ieh sugges ts a break (Figs 0 5 and 6) c
On 4 May 1964, a sample of urchins was collected from Sunset Bay,
brought back to the University of Oregon and placed in aquaria of
aerated sea water at 11 0 Cu On 6 May, four urchins were individually
marked with nylon monofilament and returned to the tanks. On 8 May,
the tips of all primary spines in the interambulacrum nearest the
mark were removed and placed on a card in the order of removal o The
position of the mark was recorded to insure proper matching of the
tips with the spines at a later dateo Figure 6 shows one such pairing
after two months of regenerationo A new tip and a new cycle have
formed c
If a spine breaks many times during the life of an animal, older
animals should have more breaks per spine. and there should be a
general correlation between size and number of cycles in oT4~inal
spines, ioe. those spines ~iCh have never been totally regeneratedo
Indeed, this is the caseo Spines from animals taken from Sunset Bay
on 8 December 1962 and 22 January 1963 were ground in longitudinal
21
Figure 5
Longitudinal section of a primary spine of StrongyZocentrotus
puropux>atus showing the calcite crystals (the "cycles of wedges"
in cross section) terminating at sharp discontinuities o Note the
partial "cycles" near the top of the spineo
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Matched spine tip and spine (with regererated tip) showing the
addition of a "cycle"o Regeneration time was two months c
{ I
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section and examined for the presence of a green corSe It was felt
that green cores indicated original spines as suggested by Swan (1952).
Of 33 animals~ only 12 showed at least one green-cored spine of the
three or four spines sampled, Because of the effort involved in
preparing longitudinal sections, no further slides were made ~en a
spine with a green core was found for any animal o As shown in Table
2. there is a positive correlation between test diameter and number of
cycles in the spines.
Regeneration of entire spines has been demonstrated with Eahinus
(Chadwick 1929), Psammeahinus (Hobson 1930), Arbacia (Jackson 1939)
and Strongylocentrotus (Swan 1952)0
Swan (1952) showed at Friday Harbor, Washington. that when a
spine of Strongylocentrotus was removed completely from the test, the
associated tubercle became dull after a period of time and could be
distinguished from shily tubercles of spines that had not been removed.
Because this could be a useful measure of the amount of spine loss,
the length of time for a tubercle to become dull and again shiny was
determined.
On 16 July 1964, spines were removed from the interambulacrum
opposite the madreporite of each of 70 urchins at Sunset Bay. After
treatment~ the animals were placed into a deep tidepool about 15 m
south of the eel grass area and at approximately the same intertidal
level o Urchins were collected periodically and the tests cleaned in
NaOCl o Tubercles became dull in one week and apparently returned to
the shiny condition in about three months c However, after three
months, many animals appeared to be new in the pool, so it is
26
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Table 2
Number of cycles in the spines of urchins collected from
Sunset Bay on 8 December 1962 and 22 January 1963 0
~
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Test diameter (cm) No. of cycles
7071 9
6 0 20 8
6 0 20 8
4 0 69 6
4 0 57 8
3 0 51 6
20 65 6
2 0 41 5
20 41 5
2020 6
2011 5
20 09 5
correlation coefficient r = o 91
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possible that the last sample did not represent animals that had
originally been treated o The experiment was repeated in 1965 0 On
28 July 1965~ animals were collected and marked with nylon mono=
filament. After the primary spines in the interambulacrum opposite
the marked ambulacrum had been removed~ the animals were returned to
the deep tide pool at Sunset Bay that had been used in 1964 0 Tubercle s
were dull after one week as in 19640 A sample taken on 8 November 1965
showed dull tubercles; however~ samples from 2 February and 18 Feb-
ruary had shiny tubercles o Because tubercles were in very poor condi-
tion in November and in fairly good condition in February~ an estimate
of five months for restoration of the shiny condition does not seem
unreasonable 0
Growth Lines in the Plates of the Test
Plates of the test~ both coronal and genital~ have been used
(Deutler 1926; Moore 1935; 1937) in attempts to determine the ages of
urchins 0 Growth of echinoids e by addition of material around indi-
vidual plates and by addition of new plates. has long been knowno It
is mentioned by Agassiz (1874) and was probably understood by Valentin
(1842)0 The incorporation of pigments into the growing meshwork to
form growth zones was apparently first pointed out by Agassiz (1904)0
Deutler (1926) examined thin sections of plates of Eahinus escuZentus.
but because of technical difficulties switched to the method of impreg-
nating the skeletal parts with terpineol and methylbenzoate as dis-
cussed by Becher (1914)0 He suggested that the colored material was
the result of different diets at different times of year and that
"'
28
anLmal migration could account for thiso Moore (1935) examined the
growth lines in genital plates and decided that lines were annual~ were
produced by echinochrome pigment~ and that this was the result of
different foods at different "times of year. Awerinzew (1911) found
that feeding red algae to StrongyZocentrotus d~)achiensis caused the
animals~o become red. With this background, I also attempted to
determine the ages of animals from test plate morphologyo
Figs" 7 and 8 show thin sections of coronal plates which indicate
a large number of 1ines o If only major lines are chosen!the results
indicated in Appendix II for 29 December 1963 animals are produced.
There appears to be more than one line per year.
Genital plates from animals collected 30 November 196j were
ground and the lines examined. The results~ however~ were not at all
interpretable. The m~imum number of lines was four in an ani~al
6016 cm in test dia~etero Four other animals of about the same size
(6 0 41 to 7050 em) each had 3 major lines in the genital plateso The
number of lines in the genital plates and the major lines of the
coronal plates do not seem to be correlated o
An attempt was made to determine the pigment involved in producing
the lines in the plates. The methods used were modified from Fox and
Scheer (1941). The absorption maximum for an acidic extraction in
diethyl ether was about 480 mu. The carotinoid echinone has a
maximum of 490 m~ and one maximum of beta-carotene is 483 m~ (Fox and
Scheer 1941), Although the observed maximum was closest to beta~
carotene there is some doubt whether this was the only pigment because t
29
Figure 7
Negative print of thin sections of coronal plates of two purple
urchins showing "growth lines 0 81 Plates are arranged in sequence from
aboral to oral~ In the larger animal (above) the small plate at the
extreme right is aboral 0 The aboral end of the smaller urchin (below)
is at the left. The test diametexs were 1.47 and 3 0 92 em. Relative
size has been preserved in printing Figs. 7 and 8 0
~ ,;
I
i
I
,:1
,.
'!-i
'.:t
31
Figtre ~
Negative print of coronal plates of an animal 6 Q 86 em in diameter.
Aboral is at the top and left~ oral is right and at tie bottom. The
nature of growth is evident: addition of material around each indli~
vidual plate and addition of new plates at the aboral end G
~ ..
7 Emlf' 'X
r,
,
.'
l
•:~
;
33
when treated with KOH~ there was a color shift toward yellow and in a
diethyl ethe: - ~OH (in water) panUion~ part of the yellow pigment
became hypophasic which suggests a xanthophyll (Fox and Scheer 1941).
In St~on.gyZoaent'l'otz.wpUl'pUl'atus'il the "gro•.qth lines" in the test are
thus not the resalt of echinochroiThiki as is suggested for Eehinus by
,
Moore.(1935). It mayor may not be the "red pigment" Deutler (1926)
found in the plates of CoZoboaentrotus. The suggestion that the pig-
ment in the test is a carotinoid 15,in itself,interesting because
Vevers (1963) states~ "In echlnaids carotinoid is principally, if not
exclusivelys restricted to the gonads~ although the marked sensitivity
of these forms suggests that is may be fliresent in the skin o Ii The
pigment apparently l'll\1lst be hound to the calcite crystals because it is
sw~a[Y of Results on the Investigation of Spine and Plate Growth
The cycles in the spines represent breaks and subsequent regenera~
tions. Other conditions being the same~ large animals can be expected
to have more breaks in their 'spines than do small animals. After a
spine has been removed from an urchin, the associated tubercle becomes
dull in about one x-leek and again gains its shiny luster in about: five
months. Growth of the spines is a dynamic process with controlled
deposit.ion and uptake of calcite. The pigment causing "growth zones"
in the coronal plates appears to be a carotenoid but no explanation
has been offered for its deposition t and the relationship of the lines
to age is obscure.
34
Fig. 9 aThd! Table:3o The distrio\\i!tions in all three areas are bimodal;
tn'Jt shift i£~ the right as sampleiS from the Postelsia zone~ eel grass
a~~a and bO\\i!lder field are cootpared. The shift in the positions of
I!~ July JL965 ~ ~ample$ of animals ~let'e aga1.n measured in the three
at'~~s. In addition to these~ several other locations were e~aminedo
These are indicated on the map of the bay (Fig" 2) and the distributions
c~rrelation with intertidal position is not as good. The largest are
A general ~orrelation a~ist5 between intertidal position and size.
E and F-,
(Fig~ lB,
(Fig. 2D;
Fig~ 9v to viii) are greater than in the inter.mediate regions
The mean sizes of small animals in the lowest areas (Fig. 2C~
G; Fig0 9iv, L~) which are greater than in the highest region
still found in the lowest areas but the smallest are in an internlediate
area (Fig~ 9ix). The general impression is that high intertidal areas
shown in Figu 9~) would receive leas debris than urchins lower down
--------------_._~._.<---'''~."._---,_._----, ..
35
separation of Modes I and II (Table J),
i
x
v
ix
it
iv
vi
iii
vii
viii
Distribution
Size 1istrib~tions of animals at Sunset Bay for 1964 and 1965~
Area Hap lotCat:ion (Fig. 2)
Por-; tt; Ls'l,t! ~one 1964 A
P08teLsia zone 1965 A
Eel grass area 1964 :B
Eel grass a:rea 1965 B
B01.ilder field 1964 C
Boulder field 1965 C
South and below
Poste"Lsia zone 1965 E
North and below
Postelsia zone 1965 F
lolest and north of
eel grass area 1965 G
High area above and
north of Postelsia zone D
To be u§ed together with Table 3. Arrows indicate a~ arbitrary
1 3 5 7 1 3 5 "7/
10
5
II
...
III IV
V vi
vii viii
>- 10
u 5
z
w
:)
o
w
e= 10
w 5
> ~--
t-
«
...J
w10
n:: 5
IX X
10
5
1234567812345678
TEST DIAMETER (em)
1
1,.;;1.. =c:;-,.._-====:;;r::t~.-:;; =..:.::.. : ::. '.>.-."'-.-...''''-.'........."'-... '/';'."~''''.. .....;'~...•........•,lI;c~.•.: .. ".,.".!~~.\.W,J..•.~.I't I .". . . . ,' " " , " ," -," •• " .., f M~I"'~'" I'. 'j'" U6~
,. """'''''''~~~''''!~~~il'\IIfII.~~~
Table 3
. Positions and importance of modes in size distributions of animals at Sunset Bay.
Distribution Date Number of Animals Mean ± SD Relative Importance
(Fig. 9)
Mode I Mode II Mode I Mode II Mode I Mode II
i 8-8-64 131 172 1.38 + 0.43 4.68 + 0.45 43.2% 56.8%
ii 7-22-65 69 86 2.21 + 0.57 4.92 + 0.59 38.7 61.3
iii 8-10-64 200 111 1.62 + 0.49 5.18 + 0.40 64.3 35.7
iv 7-9-65 145 93 2.44 + 0.65 5.69 + 0.65 60.9 39.1
v 8-9-64 175 136 2.95 + 0.61 7.08 + 0.63 56.3 43.7
vi 7-29-65 92 84 4.07 + 0.69 7.15 + 0.69 52.0 48.0
vii 7-28-65 21 83 3.00 + 0.53 6.16 + 0.85 20.2 79.8
viii 7-28-65 22 100 2.50 ± 0.56 5.20 ± 0.60 18.0 82.0
ix 7-23-65 73 145 2.39 + 0.65 4.80 + 0.66 33.5 66.5
x 6-28-65 194 27 2.08 + 0.80 5.28 + 0.42 87.8 12.2
Relative intertidal positions starting with the lowest: E and F, C, A, Band G, and D.
w
.....
Ji ..t~.•~. 'I;
;1·.'·····
, ' .. -.
, .--:
~I
{
I. ~.
t
ti
,
..."
38
covered by moving u2tet, There would also be e~tremes of temperature
and salinity lvith. associated changes in oxygen tension.
t~aJ1ination of the distributions indicates that there are differ-
ences "_n the relative importance of the two modes. There is a decrease
in relative importance of the large animals from low to high intertidal.
Changes in importance of the first mode in the three major regions
from 1964 to 1965 are shown in Figo 9 and-Table 30 The relative
decrease in all three cases is about 4%0 This suggests that differ-
entia! survival can not explain differences in the relative importance
of the two modeso It is possible. chance factors causing mass mor~
tality in the high areas could explain the intertidal differenceso
Drastic ~hanges in salinity during heavy winter rains could kill large
n~ubers of anL~als~ as could a~tremely high termperatures during low
tolerant of e%treme conditions tlan are large anL-nals. Urchins over
1 em could not be maintained in the circulating sea water system
desc~ibed earlier, althou~h small animals could be kept with no
trouble. Four small animals (0.5 cm to 1.2 em) were kept for three
months in a I-gal. jar at 110 C without aeration~ food or changed
~vater. At the end of '; I:S time~ three animals were still alive (one
had been eaten by the others)~ and the salinity was so high that
crystals were forming in the watero There is no question that there
is a loss of tolerance with increased size. This may be very L-nport-
ant in e}l;plaining the changes in importance of large animals with
39
changes in intertidal position. If only extremes of temperature or
salinity cause mass mortality, it is possible that no such extremes
occurred during 1964-65, and so the mortalities for the year were the
same in the three major areas. If information were available for
several years, differences might indeed exist.
Examination of Growth Rates in the Three Major Study Areas
As can be deduced from the size distributions, differences in
growth rates exist among animals of three major study areas. This
was conclusively demonstrated with marked animals placed in the three
areas in the summer of 1964. Changes in the diameters of these animals
confirmed that differences in growth rates existed and, quite unexpect-
edly, that urchins are able to decrease in diameter. Examination of
Fig. 10 shows that animals grow most slowly in the PosteZsia zone,
most rapidly in the boulder field and at an intermediate rate in the
eel grass area. Each point represents the mean of five measurements
of diameter, both for the initial diameter in 1964 and for the change
in diameter as measured in the summer of 1965. Lines in Fig. 10 are
least squares regressions. The test for the significance of differ-
ence was by regression analysis (Dixon and Massey 1951, pp. 216-219).
The 0 intercept for the boulder field animals is 6.13 em; it is 5.11 em
for animals in the eel grass area and 4.64 em in the PosteZsia zone.
Animals showing negative growth in the eel grass area have not been
plotted in Fig. 10 simply because of the congestion of points but are
shown in Fig. lOA. The maximum amount of shrinkage observed was
slightly more than 3 mm and was in an animal from the PosteZsia zone.
40
Figure 10
Diameter changes over a I-year period in each of the three
major areas determined from marked animals o Each point represents
from 3 to 5 original diameter measurements (the mean is plotted) and
5 measurements 1 year latero Standard errors for representative
changes in diameter (6d) are given in Appendix Va Negative values
for eel grass animals are not shoWD o For these see Figure 10Ao
+ PosteLsia zone
o eel grass area
• boulder field
1.8
1.6
1.4
1.2
~1.0
E
~ .8-
0::
~ .6
w
2 .4.
«
0+.2
<l
o
\. .
•~\
+
•
•
1 2 3 4 5 6
ORIGINAL TEST DIAMETER (em)
42
Figure lOA
Diameter changes of marked animals in the eel gra~s ares o
- b. . £Z..
2 3 4 56
ORIGINAL TEST DIAMETER (em)
1.8
1.6
1.4
1.2
,,1.0E·
~ .8
0::
lJJ~ .6
~ .4
<l
-
0+.2
<l
o
o 0
o
o
o
44
the testo The ability to take up ~al~ite in such a manner that the
Seasonal differences in grow~h are shown in Table 40 Growth
appa~ently was greatest from July to Decembe~~ least during the
In summer 1965~ animals were again marked and pla~ed in all three
areas 0 A total of 201 1bltn:hins were gathered from the eel grass aI'ea~
ar",a 0 62 to the PosteZsia :wne and 12 to the boulder HeldL, As shm,yn
in Table 4 9 there is apparently no difference between growth in 1964
and 19650 Short=term effects of marking were e~amined by comparing
the growth of animals marked inl964 with those marked in 19650 The
two time periods ~amined~ July to November 1965 and Novembe~ 1965
to Ma~~h 1966$ are not significantly different with r~spect to time of
mall.'ld"ng (Table 4) 0 Possible effects of handling animals were assessed
by comparing the diameter changes of animals recaptured only once
after marking with animals recaptured twice and three timeso Handling
apparently has no effect (Table 4)0
... _. . . - • - ',.:-::,'.- '. -''' .. '. - ' ' - -- -, }!"_" .. :','.'_C,.<",,' ',', 'L;"""''';ii;I~~'fJ;k~~;';f{~ "'-,1', .,-.~,:.';, ••::~. ~f}~~.rl§~~{~~~'V~:",~:~: ..t;:.:;, ",'1< .
Table 4
Analysis of growth information gathered from marked animals in the PosteZsia zone (PZ), eel grass
area (EG) and boulder field (BF). Comparison by regression analysis (Dixon and Massey 1951, pp. 216-19)
~
~
_.,....,:~
'.i'i:::
Dates Number of animals examined Significance of difference Regression equations
7-64 to 12-64
(summer and fall)
12-64 to 4-65
(winter)
4-65 to 7-65
(spring and
summer)
7-65 to 11-65
(summer and
fall)
11-65 to 3-66
(winter)
7-64 to 7-65
(one year Fig.
10 and lOA)
PZ
58
32
34
24
15
63
EG
33
8
32
60
43
71
BF
32
6
6
8
3
30
among areas
F4,117 = 22.82, p<.Ol
F4 ,40 = 1.65, p>.05
F - ..4,66 - 7.14, p<.05
F 4,86 = 10.83, p~.05
F 4,55 = 4.13, p>.05
F4,158 = 36.4, p<.Ol
PZ y = -O.92x + 1.07a
EF y = -1.47x + 1.53
BF Y = -1.37x + 1.58
y = -0.18x + 0.61
PZ Y = -0.32x + 0.76
EG Y = -1. lOx + 1.30
BF Y = -0.85x + 1.16
PZ y = -0.27x + 0.73
EG Y = -1.13x + 1.35
BF Y = -0.68x + 1.20
y = -0.17x + 0.61
PZ Y = -1.43x + 0.94
EG Y = -2.77x + 1.97
BF Y = -2.83x + 2.28
a x = original diameter in logs, y = change in diameter (~d) for the specified time period
~
VI
)'. .. '~'.,,, "'it '·'/;"i''':~1t-<''''''''~.r~,=~::r;,··,.,.·,·q,---~--::;a/.::'-".~ ;,~l .;,._ Ph,_, .in ";'~f~-~7~~,~:.ti~~*~~~z,.~ ....b~t,;;r"''' ~-{;~;~.:'~-~~,~
Table 4 (cont.)
Dates Number of animals examined Significance of difference
Area 1964 1965 between years
Summer and fall
1964 with summer PZ 58 24 F2,78 = 7.22, p>.05
and fall 1965
EG 33 60 F2,89 = 2.44, p>.05
BF 32 8 F2,36 = 1.61, p>.05
Winter 1964 with all
winter 1965 areas 47 61 F2,104 = 0.16, p».05
Assessment of short term effects of marking by comparing animals in the eel grass area marked in
1964 ("old") with animals marked in 1965 ("new").
7-65 to 11-65
11-65 to 3-66
"old"
24
16
......
"new"
36
27
between animals newly marked
and those marked the previous
year
F2,56 = 2.29, p>.O?
F2 ,39 = 0.02, p».05
.J:--
0'
t ":::~'~:~~....~ .. ~ :.w-....: • .._-i..~~~;'; .. ,-,,:.~;'ih·:';",ii;;~2W"·""".iil\_.IM\l;:"·IO'··",·,<·~i :·;;i'.~~.~·.'(t.r.I~·"j···~'I· '0' •••••• 0".',,7:, .'-' '.'0-.1,; ~ .,: ... too·,. _., •. ~ .-.; .. - ,:,;j:."- L. _", ,·.~·,:C~. ""I. "". -', . ~._-~, ~ ..;1 &.t,,' ,y ,«.(c;~' '. .~.....< "'................,;.;... ;
Table 4 (concluded)
...~
"f"
Assessment of effect of handling animals on growth by comparing animals marked in 7-64 and not
remeasured until 7-65 with animals recaptured and measured twice and three times.
7-64 to 7-65
Area
PZ
EG
Once
11
22
Twice
25
38
3x
22
12
among numbers of times recaptured
F4,52 = 1.71, p>.05
F4,66 = 4.01, p>.05
.j:>.
"-J
48
Growth data from individuals marked in summer 1963~ althou~h
limited $ are shown in Table 50 As previously indicated~ tag loss
could accoamt for the poor reccrve1ty of animals in June 1964 c The
general information at least does not contradict the results obtained
in 1965.
Examination of the ~hifts in positions of the modes in the size
distributions (Figo 9) from 1964 to 1965 and calculations of the
positions of modes for age classes based on the growth rates established
from marked anL~alsa indicates that good settling occurred only in
1963 and that 1962~ 1961 e 1960 and possibly 1959 were years of poor
settling. The years 1964 and 19.65 were observed to be poor for sett=
Associated with the differences in growth rates in the three
areas are differences in gonad production and organic material (exclu=
sive of the gonads)" A uugonad indeJ!;" such as used by Lasker and
Giese (1954). Bennett and Giese (l955)~ Greenfield ~~. (1965) was
not used to describe gonad development because the relationship be-
tween total size and gonad 812e is not linear as~ indeed s has been
.ho,rn by Hoore ~.!!. (1963a)0 Moreover e when both calcite tv eight
and gonad weight are converted to logar1thms,the regressions do not
pass through the origin$ so that use of a ratio is invalid if samples
of different sized animals must be compared (as is the case in this
study). Moreover& the individual samples in this study have such great
variability in gonad development that regressions for a particular
season are somewhat meaningless with the numbers of animals used o
49
2
4
4
3
1
1
1
1
1
1
Table 5
5053 ± 0,010
6,,00
3.~4 1: 0 0 021
4etQl2 + 00013
Mean diameter ± SE
6=64
1
Animal
~.,.~.,..~.. ,
1
;1
\
50
The less precise analysis based on maximum developm.ent seems to he
more appropriate (Figo 11)0 The trend~ as shown in Table 6~ however~
are probably valid or at least they seem to he in the expected direct=
ion~ they indicate greatest production in the boulder field and least
in the Postelsia zone o There is a suggestion of a major gonad build=
up in fal1 0 Some spa,~ing animals~ however~ have been observed in
both winter and summer, possibly the suggestion of Giese ~!!,o (1958)
that ~here is no definite season is correct o
There are differences in amounts of organic material (other than
gonads) among the animals with respect to time as well as area o The
pooled data for each season (Table 7) represent about 60 animals per
sample with about 20 per area or 10 per area for each of the two
collecting dates of a seasono Samples were pooled in the fol10'l:¥'
manner~ fall is 23 September 1964 and 23 October 1965; winter is
30 November 1964 and 29 January 1965; spring is 15 March 1965 and
11 April 1965; and summer is 21 June and 31 July 19650 Regression
analysis was used to test the adequacy of a single regression to
describe animals in the three areas for each season o Only in summer
was there a significant difference (Table 7)0 In summer~ animals of
the Postelsia zone had less organic material for a given size than
did animals from the other t.l0 areas (Figo 12)0 Eel grass and boulder
field urchins were not significantly different (Table 7)0 There was
mo~e organic material in samples in fall than in summer~ less in
winter and spring and an increase again during surnmeLo Animals from
the Postetsia zone apparently do not reccver as rapidly as do urchins
51
Figure 11;,
Gonad size as a function of total calcite weight, All dates
are pooledo
+f Postelsia zone
'"
0\' eel grass area
., boulder field
A conversion table for calcite weight into test diameter and
wet weight is given in Table 13&
•"8 • • •• •E. • • • •Ol •
'-'7 ••J- •I • •Ii • •
<.96 • •• •• • .'- • •W • • •~5 • • •0 • .0• • ••0
0 •
>- 0
~4 ••0 •0 •
.0 •
Cb • • •03 0 o +.0 o 0
« tJ o 0 00 0~2 0 0 o.0 o. 0o <0 0 •Co 00+:.. 00 O' 0 0CD 0 0 +0 0 + 0 •+ + +
1 ++" .... +#0 + •o :. ~1+ -t:/++ + + •cP.. ++++ 00 :+<1+ at~~++ .+. ++ ++ ++ + •o· 'i-+ .+ + ..o + +++ +o~.2-._+ ++ +
gm 10 20 30 40 50
CALCITE WEIGHT
.J _
11
9 •
•
•
•
Table 6
Differences in g,nad development among the three major areas o
Values for each area are the numbers of animals with gonads from
o to 49% and 50 to 100% maximum size (determined from Figure 11)0
53
------
Fall
Winter
Spring
Summer
20
20
18
19
o
o
1
o
10
9
12
10
10
8
5
1
4
11
9
15
13
9
11
,. _, ',,'.?N~~~;'~.""';t~~a->··~'·'*'!\tt;'d'l'~V.~" )'?f:'t.j','t:':'~.6,~~~,f·,lt'''i~.~·'.1i'ji.~~~
~'i~~""'>.o/""""",,·,··,,","·t'V~' ; ..' '. . . .. . '.
i-#"~~""~~~:1>~/#,~:Il'I~~.·.~~~~~'tt:~~~'\'> w"··"''''''''~.r*'¥f''~¥,~~1'Y:;'''''j'' .",+;",c~~t.,~r',:~~~~,;",:;,.~""t'f<''''''I<>",,,,,~.'~ll"'f~~<~'
Table 7
Regression analysis of organic material in animals from the PosteZsia zone (PZ), eel grass area
(EG) and boulder field (BF).
Season
Fall
Winter
Spring
Summer
No. of animals Significance of difference
PZ EG BF between areas
20 19 16 F4,49 = 4.22, p>.Q5
20 19 17 F4 ,50 = 2.3, p>.5
19 20 19 F4,52 = 0.23, p>.O?
19 19 20 F4,52 = 21.13, p«.Ol
19 20 F2,35 = 7.73, p>.05
Regression equations
y = .120x + 0.33a
y = .100x + 0.21
Y = .100x + 0.10
PZ Y = .077x + 0.35
EG and BF y = .107x + 0.25
Fall, winter and spring should not be described with a single line. (F4,163 = 15.98, p<.Ol)
Winter and spring can be described with one line (F2 110 = 2.46, p>.05; y = O.lOlx + 0.14).,
ax = calcite weight in grams, y = total organic dry weight in grams (other than gonad dry weight
and gut contents).
tTl
.f:::>.
55
Figure l2~
Organic weight (gut wall and tissues of the test~ spines and
tube feet) in the summer as a function of total calcite weighto
Lines are least squares regressions o Other seasons are given in
Table 70
+ Postelsia zone
o eel grass area
~ boulder field
A conversion table for calcite weight into test diameter and
wet weight is given in Table 130
_._-- -_. -_._------._--- --------_.._----- ..
o
~
o
(Y)
l-
I
~
WOs
C\I
W
t--
-U
-J
«OU
~
•
•
CD LO ~ (Y). C\I ~
(Wo) lH813M JIN'v'8~Ol
i~;
I
1g
$'
i~.~
~
57
in the other two areas. A cycle of stored glycogen in the wall of the
gut was found in So purpuratuB in California by Lawrence ~.!!. (1965).
The changes in organic weight shown among animals at Sunset Bay pro=
bably represent this cycle of stored food.
As indicated in Methods~ ~o general features of the environment
are to be considered as possibly L~portant in determining the rate of
growth and ultimate size of individualsg surf exposure, which could
regulate growth by requiring energy expenditure for spine repair and
replac~entID and food availability.
Effects of Spine Breakage on Growth
During the spring and summer of 1964~an experiment was conducted
to test whether breakage of spines could have an effect on increase in
test diametero On 24 May 1964~ 46 age=class I animals were collected
at S~nset Bayc On 25 May~ the urchins were divided into two groups
and measuredo Spines were cut to within several millimeters of the
base in one group and the animals were returned to aquaria and main=
tained at 11° Co Individuals were again measured on 21 June, 29 July
and 25 Augusto Urchins were transported from Eugene to the Oregon
Institute of Marine Biology at Charleston on 16 June. At first,
animals were kept in wooden and glass aquaria but they did not seem
to adjust properlyo On 21 June$ the animals were measured (the spines
of the experimental group were not again broken) and the animals were
moved to a plastic wading pool with rocks and kept in running sea
watero Spines of the experimental anim~ls were again broken on
29 Julyo For the entire exper~"~nt animals were fed the brown alga
, .
f
j
I
i
'I
_--.....
58
HedophyZZumo By the end of 97 days~ the control and experimental
means had diverged sufficiently that they were statistically distinct
(Table 8)0 This indicates that spine breakage and subsequent repair
can have an effect on the increase in test diameter of an urchin and
that~ other environmental factors remaining constant, animals which
must repair spines will increase in diameter, or "grolv" in the sense
of this study~ more slowly than animals which do not have to expend
energy in this fashion o
Breakage of S,ines in the Field
The first method was to measure breaks in spines o A total of 85
animals were examined: 30 from the PosteZsia zone, 24 from the eel
grass area and 21 from the boulder fie1do Five spines from each
animal were impregnated with an oil of the same refractive index as
calcite, as described in Methods s and viewed by transmitted lighto
Figo 13 shows the maximum break measured for each spine as a function
of test diametero The only relationship is that larger animals show
larger breakso The three areas are not significantly different (Figo
13)0 There is a suggestion that if a force great enough to break a
very large spine ~~e applied to a somewhat smaller spine, the spine
would be ripped completely from the testo Conditions apparently are
severe enough in all areas that a linear relationship between diameter
of maximum break and test diameter is maintained throughout the range
of observations o Under less severe conditions,a curve should be
produced which would approach a break diameter characteristic of the
set of conditions ioeo the less severe the conditions the smaller
.'._~~~.~,;:"-,~.'~~~~~'::"' . ~~..:t·:~·-,~,,;,;,:/tXl::":'·· ,·,W· "'ep' " "d" ·""·i1t:\·<-'z;;tP"~=-o!"i';¥"~n="" ·~~~"'!r-'::t''''~:7rJ':rn::~;;tl •.''~_~:~. ;:;q;r ::-·::·"";lo·?:tlt~"........=r:·~"',~l1,,·;;;u.""':r"r,~,l"~.,.. i: ~. ':;.' ':':i ... & .. . -. J..... ..................... :it.1 b Miss .,w ';'Ii""
• .', . "'-;'. , ..... "..'7.'1, '<'j,'", .;·:.,,:..:.~I. -.:. ~>..r.,~),,>-...,.:, ',; .'~:;' .
Table 8
Effect of spine breakage and regeneration on increase in test diameter. Experimental animals had
spines broken on day zero.A~d after 65 days. Diameter means are from 3 measurements and are in centi-
meters.
Date Time in days Experimental Control
5-25-64 0
6-21-64 27
7-29-64 65
8-20-64 87
No. of animals Mean diameter + SE
23 1.61 + 0.05
23 1. 61 + 0.05
22 1.87 + 0.09
22 1.87 ± 0.09
No. of animals Mean diameter + SE
23 1.64 + 0.05
22 1.66 + 0.06
23 2.05 + 0.07
23 2.10 + 0.07
After 87 days the variances of the two samples were still the same (F21 22= 1.92, p>.05),
The means are significantly different by at-test (t = 1.98, df = 43, p<.05).
lJJ
t.O
60
Figure 130.
Maximum break seen within at spine as a function of size of
animal. Five spines are ,sho,~ for each animal. Some points in
the ~enter of the distribution and eel ~rass animals have not been
plotted.
The three areas are not significantly different by regression
analysis (F = 4.34$p>.05)o The regression equation isg
41)314
y =Oo118x + 0 0 18 where x = test diameter in centimeters and
y = ma~Lmum break in millimeters.
+ Postelsia ~one
• bo~lder field
'i>,~
;
'!t
~~
~
';;.
~:
~~
f
I
tr::
-t
~
1 .
'J. f
f
~
~~
~
ii
~'
,~,
i
l~
,
i ,.~,
i
r
I
II
•~
E •E1.5 •
..........,
•~ •
••! « •; w .,. ••
•1 C:': + •1 en t· •••• .11•f·
-4t. ••l + • •~1.0 ... + t+· i·:+ -f.+ .•
+ .... +T+ + •••2 +++ ++t;~+~ h. ••
- • + ~ :+.+ :to+.+..... • •x + • i=:.t-T ••+ +. + + ++\++ •
« + • :1::••++++++++. •2 . ~+.e+.t ++++.+ ...... ++ •• + +
LL + + +.. +
-
.5 1: + .... +0 +
-.t .+-
+f +c::: t +W
t- ++++w +
2 .1
«
0 1 2 3 4 5 6 7 8
TEST DIAMETER (em)
.1
I
j
,1
1
62
the ma%imum breako It is expected that subtidal populations will
show thiso
Complete Removal of Spines under, 1iE!ld COJl<!itions
As shown in Methods~ when a spine is completely removed from the
test the associated tubercle becomes dull in about one week and& with
regeneration of the spine~ becomes shiny again in from three to five
months 0 Primary interambulacral tubercles from samples of animals
collected in August 1964 were examined and recorded as either shiny or
dullo The IUpercent dull tubercles" of an animal represents an
accumulation of spines ripped from the test over a 3= to 5-month
periodo For any given test diameter,tbe animals of the boulder field
show a greater number of lost spines than do urchins of the other
two areas (Figo 14)0 Furthermore~smaller animals lose relatively
more spines than do large animals o This is not too surprising con-
sidering that a force just strong enough to rip a primary spine from
a small animal would only break a primary spine on a large individual o
Spine breakage and regeneration are apparently~ in this case, not
adequate contributors to size regulation, the area with the greatest
amount of spine loss also shows the highest growth rate o Although
spine breakage was shown to be important in regulating growth rates
in the laboratory (Table 8)j it must be concluded that there are more
tmportant factors involved in regulating urchin growth in the particu-
lar areas at Sunset Bayo It is possible~ however, that situations
do exist where spine breakage in the field could be important o
63
Figure 14"
Percent dull tubercles as a function of test diameter. All
primary interambulacral tubercles were examined for each animal.
The three areas are significantly different by regression
analysis CF4 68 = .39.n~ p«.Ol) •t
+ Postelsia zone y = =4.58x + 32.12
0 eel grass area y ... =4.49x + 29,50
• boulder field y "" =3.74x = 39.72
, ,
, .
~ ~
jl~
00
+
••
+
•
o
•
•
•
•
E
L---,.....-------r------.,----r-----' U
o 0 0 LO.
(Y) C\I ~
S31:)Ll38nl llna 0/0
65
A second possible factor causing growth differences is the amounts
of food eaten in the three areas o This was examined s as described in
Methods 9 using tattooed algaeo A major problem with this technique
was that it was not possible to tell without dissection whether an
animal had indeed eaten the marked food o This possibly could have
been obviated by using isotope labelingo The success of recovery of
marks was very variable and is shown in Table 90 Generally 9 the
animals in the boulder field were less likely to ingest the marked
algae than were animals in either the eel grass area or the Postelsia
zone o The highest and most consist~nt success was in the Postetsia
zoneo In the July and October 1965 samples~ none of the animals from
the boulder field had a narko This makes comparisons with the other
areas impossible for these time periodso Figo 15 shows the variability
in the food gathered in one dayo The boulder field data are presented
in Table 10 0 Data for the critical summer months are missing for both
the boulder field and the eel grass area o The rest of the year5 with
the number of animals dissected and the degree of variability within
a single sample, does not show significant differences in the
amounts of food eaten in 24 hours between the PosteZsia zone and the
eel grass area (Table 11)0 The positive correlation indicated by the
Corner Test (Table 11) simply means that large animals probably eat
more than small animals and is not very profoundo In retrospect 9 the
degree of variability is expected because urchins are opportunistic
in their feeding habitso Thus on any day~ an individual mayor may
Table 9
Recovery success of tattooed pieces of algae 24 hours after feeding to animals in the field.
Date P08te"l8ia zone Eel grass area Boulder field
No. with mark No. without No. with mark No. without No. with mark No. without
9-23-64 5 5 9 1 2 4
11-30-64 7 3 6 3 4 2
1-29-65 8 2 6 4 2 9
3-15-65 9 0 10 0 5 5
4-11-65 7 3 7 3 6 4
6-27-65 9 0 6 3 3 7
7-31-65 8 2 1 9 0 10
10-23-65 9 1 6 3 0 10
--
total 62 13 51 26 22 51
Percent success 82.7 66.2 30.1
0\
0\
67
Figure 15,
Rate of feeding as a function of size as determined from feeding
animals tattooed algaeo See! ble 11 for statistical analysiso The
line was fit by least squares regressiono
A conversion table for calcite weight into test diameter and wet
weight is given in Table 130
+ Postelsia zone
o eel grass area
f+
LO
... C\I
+ 0 0
+
+
o + 0
0
-a00 0 C\I
0
0 + + ++ t-
o o + + 00 I+ + ~ 0 <.!)+ 0 + + 8 +0 + 1.0-
+ ,+ 0 + ~W+
0 a + o 0 1> S
+ w+
+ :+ 0 *++ I--
+ +
+ f aU~.....J
+ + 0 ~ ... <(0 + u+
+
+ 0 0)\+ + 0 to
o 0 0
0 ~ \ 1; ~ 0
•
+
o
+
I
LOa LO
(\J ~ ~ a
5t1nOH VG NI GOO;:! =10 SlAJV'tJ8
Table 10
69
036
052
048
017
065
034
002
004
003
004
002
organic material
eaten in 24 hours
3200
30 0 8
804
103
5 0 4
4803
3909
38 0 8
19 0 6
Total calcite weight
Rate of feeding of animals in the boulder fieldo The material
Date
eaten in 24 hours was determined by tattooed algae fed one day before
collectingo All values are in grams o
1=29=65
11=30=64
9=23=64
4=11-65
6=27=65
7-31-65
10-23-65
38 08
3100
18 0 1
509
407
3 0 5
None
None
031
012
013
010
011
004
052
019
005
Regression analysis of the organic material eaten in 24 hours
eaten in 24 hours as determined by use of tattooed algae o
between areas
among seasons
Significance of difference
F = 1013, p>005
2,106
7
17
16
16
10
15
EG
48
No o of animals
14
15
Fall Winter Spring Summer
PZ
62
EG
PZ
Table 11
70
By analysis of variance the slope of the least squares regression
x ~ calcite weight in grams and y = dry weight of organic material
All 4
Season Area
by animals in the PosteZsia zone (PZ) and eel grass area (EG) where
is not significantly different from zero (F = 00198, p>005)o
11)108
Using a Corner test (Tate and Clellana 1957), a positive associa-
tion is suggested (Quadrat sum = 23, p>oOl)o
71
not catch a large piece of floating debriso This means that increased
precision could be gained either by increasing the numbers of animals
in a sample (probably by at least a factor of 4 or 5) or by increasing
the number of days between the feeding of the tattooed algae and
collecting the animals o This latter method would~ however 9 increase
the length of time of food in the gut and so increase loss of \ eight
by digestiotllo
The total amount of organic material in the gut for a given size
is presented in Table 120 The amounts are about the same for all
seasons ~~cept winter~ when the amount is lowero This suggests that g
if differences in amounts of food eaten do exist among the areas g
there would have to be differences in the rates of turnover of the
gut contents o Possibly a study of gut content turnover times using
radioisotope labeling could lead to a relatively simple estimate of
feeding l'ateso
Distribution of inorganic components of the gut contents is
shown in Figso 16 and 110 Confidence intervals are two standard
errors of the mean of the ratios after casting out extreme values
(all values are given in Appendix 111)0 The actual interval can not
be taken too serio~sly~ particularly for animals in the boulder
field~ since ratios are not normally distributed o Thus~ although
the central values (Postelsia zone and eel grass area) can be mani-
pulated without a transformation,the extremes (the boulder field
ratios) sho~ld not be used without transforming {eogo arc=sine)o
The general L~pression is that the inorganic components {carbonates
Table 12
Regression analysis of total organic material in the gut of animals from the PosteZsia zone (PZ),
eel grass area (EG) and boulder field (BF).
Season No. of animals Significance of difference Regression equations
PZ EG BF among areas
Fall 20 19 14 F4 ,47 = 2.72, p>.05
Winter 20 17 17 F4 ,48 = 3.84, p>.05' y = O.Ollx + o.lZa
Spring 19 20 20 F4,53 = 0.16, p>.05
Summer 19 19 ZO F4 ,5Z = 1.34, p>.05
~~amo~~seasons,
All
seasons 78 75 71 F6 216= 8.49, p<.Ol,
Spring,
summer
and fall 58 58 54 F4 164= 0.56, p>.05 Y = 0.022x + 0.03,
ax = calcite weight in grams, y = dry weight of organic material from the gut in grams.
-...J
N
...............
73
Figure 16
Silicous sand in the gut as a function of time o Extreme values
were removed before means and standard errors were calculated (see
text and Appendix 111)0
of eight to ten animals 0
Each point is the mean ± 2SE for samples
+ PosteZsia zone
o eel grass area
• boulder field
00
• ~ ~ ~ ~ ~ ~.~ .
i.I311V1I\J :>IN't/8tJO/ONV'S
•
. ..
•
75
Figure 17.,
CaCO
J
in the gut as a function of ttme o Extreme values were
removed before means and. standard errOl'S were calcudated (see text
and Appendix 111)0 Each point is the mean ± 2SE for samples of
eight to ten animalso
+ PosteZsia zone
o eel grass area
e boulder field
/+----0-- _
/ -"5.
/ Q)
/ If)/
/
--/--/
/
----,.,(:....--_-,
"
"
" ,
....
.
~
.CD
, +-'
'0-1--_-------------_--1(1)~ ~ <Q l.Q ~ C'1 'C\! 'r:' (/)
~311'VlI\J JINV'8~OI £O:)BJ
77
and silicates) act very differentlyo Silicious sand (Figo 16) appears
to be about the same in all three areas with an increase during the
fall~ reaching high values during the winter~ dropping during the
spring and reaching low values during the summer o The high values
during the winter possibly reflect increased surf conditions which
would carry larger volumes of sand or~ with the winter rains, increas=
ed stream run=off (a small stream enters Sunset Bay}o Urchins
apparently keep their bases clean by eating the sando It is also poss=
ibIs that this could indicate decreasing amounts of food available
during the winter so that sham feeding would increase the amounts of
sando
The seasonal changes in amounts of CaCOJ (Figo 17) indicate that
during the fall and winter the PosteZsia zone and the eel grass area
animals are essentially the sameo The boulder field animals have
much lower amounts of carbonates in the gut for all times of year o
The only val~e which approaches those olservecl in the other two areas
occurs during the winter when values may be the same as in the eel
grass area and PosteZsia zone o Values in the eel grass area drop
during the spring and are low~ essentially the same as in 'the boulder
field animals, during the summer. Lewis (1958) found that T~ipneustes
escn!Zentus Leske refused to eat algae with a high CaC03 content.
Forster (1959) suggests that Lithothamnion~ an encrusting coralline.
may not be browsed on heavilyo Coralline forms appear to survive
under conditions of high urchin densities (North 1963; Forster 1959).
Kawamura (1965) showed an increase in calcareous algae in the gut
was associated with decreased gonad production. I should like to
78
conclude from this that the amounts of CaC03 in the gut contents of
Sunset Bay animals reflects general food availability; if given a
choice& urchins would rather eat something other than corallines t but
under conditions of low food they will accept algae high in CaC03•
This would mean that animals in the PosteZsia zone have low amounts
of food essentially all year~ animals in the eel grass area have
small amounts during the fall and winters have increasing amounts
during the spring and are well fed during the summer. Animals in
the boulder field generally are well fed but do have less food during
the winter.
Another method of estimating amounts of food~ which yielded very
similar results~ was by measuring the quantities of debris held by
animals in the three areas. The rationale is that! for an opportunis-
tic feeder dependent upon debris~ before food can be eaten it must
first be caught and helda Measuring the amounts held~ although not
indicating the actual amounts eaten~ does give ~n indication of food
availability. Table 13 gives a summary of such information gathered
in July 1965 and March 1966. A more complete analysis is given in
Appendix IV. During the summer 9 animals in the boulder field were
holding more algae than animals in the other two areas. The Pos-
teZsia zone urchins had the leasta A comparison with the amounts of
algae eaten in 24 hours (Figa 15) indicates that animals in the
PosteZsia zone are holding about the maximum amount they would eat
in one day (using the conversion values in Table 13 9 •. 190-g ur~~~~
t
t
79
i:"
Table 13
Food held by urchins during summer and winter o Values for each
Conversion table for comparing Table 13 with Fig o 15
00019
0 0008
00021
March 196b
Calcite weight
50
25 g
200
100
Total wet weight
3075 em
Area
July 1965
Detailed analysis is presented in Appendix IV o
season are dry weights of food in grams per 100 g urchin wet weighto
Eel grass area
Below PosteZF~l zone
and north, (Fig 0 2 F) 0012
Boulder field
Test diameter
Below PO~+,p.l8ia zone
and south fFigo 2 E) 0041
PosteZsia zone
80
would be 5.90 cm in test diameter and would have 24.5 g of calcite).
Using this as a base, animals in the eel grass area have 1.6 times
the amount they would eat in one day and urchins of the boulder field
have 2.7 times the required amount. In the sample taken in March
19669 food is very low in all areas& but lowest in the PosteZsia
zone. Although particular details are somewhat different, the basic
picture is the same as indicated by the amounts of CaC03 in the gut
contents.
Seasonal differences in food are due to the equivalent differ-
ences in algal production and growtho During the summer, the inter-
tidal supports a lush growth of many algal species which die during
the fall leaving the rocks relatively barren during the winter. Algal
growth resumes during the spring. Local differences seem to be correl-
ated with local topography: areas of high local relief seem to have
more food which grows on the tops or sides of the ridges, hangs down
and supplements floating debris. This appears most impressively in
the boulder field where animals stay at the bases of the boulders
and have large quantities of algae hanging over them. In flat areas
such as the eel grass area little or no supplementary food hangs over
the animals. The amounts of algae which grow on the boulders or
ridges are controlled by the factors limiting algal settling and
growtho This accounts for the small amounts of algae hanging in the
PosteZsia zone even though it is an area of high relief.
Food quality has been shown to be important in determining growth
rate in StpongyZoaentrotus by Swan (1958, 1961). Differences in
81
assimilation efficiency with different algae have been demonstrated
by Fuji (1962)0 Differences in the algal composition of the three
areas are indicated in Appendix I for algae collected in the areas~
and also in Appendix IV~ which shows the debris held by urchin
samples 0 Differences do exist~ and quality may playa part in de=
termining growth of these animals; however~ generally it appears that
differences in food quantity can explain the differences observed
in Sunset :Bayo
Decrease in Gut Contents with Gonad Growth
~Wj£::e =ze:c:tt:o
Fuji (1962) indicated that~ when spawning approaches g there is
a decrease in feeding rate o A similar cortelation is shown in Fig o
18 and 200 The total weight of organic material in the gut is plotted
again~t the percent maximum gonad weighto The general suggestion is
that g up to a certain point~ gut contents and gonad size are directly
related; beyond this g increases in gonad size are associated with
decreasing gut contentso The implication from FLji 9 s work is that
this is behavioral; however e in dissecting the animals in this studY9
my impression was that this response was due to physical crowding in-
side the testo With maximum gonad development, there simply is not
enough room for maximum gut expansion 0 The variability of the values
in all three figures is so great that any single one is not very con-
vincing; h~~ever5 the trend is the same in all three therefore. even
though this in itself is not proof 5 it doeF streugthen ..he suggestion
that there is first a direct relationship between gonad size and gut
contents& a critical point is reached, and any further gonad
82
Figure 18.1
Relationship between gonad development and amount of organic
material in the gut., All seasons pooled.,
• 21 to 30 g total calcite weight
+ 31 to 40 g total calcite weight
0 41 to 50 g total calcite weight
+ ••
.'+
e+ 0 +
• •
+
+
•
0
' ..•~
I,· ."1
1
,)
~ ,"
"'I\"
,"ifi'~~ ,~
;f,,~,', '.'.'I~',:,'",.,it 'I
'I·, ',,",.t
~­
r
100
80
W
N
if)
o 60
«
z
o(9
2: 40
"::J
2: .
x
<{
2: 20
~
o. 10 •
.,
•
•
•
• •
+0 0+
.+ + 0+ 0
+ •
0
0
+
+
+
0
• +•
•
+
,.+
• •
t
I
'r I' f'
.1 .3 .5 .7 .9 1.1, t~3
'TOTAL ORGANIC MATERIAL IN GUT(gm}
84
Figure 19
Relationship between gonad development and amount of organic
material in the guto All seasons pooled o
• 11 to 20 g total calcite weight
Note change of scale o
•80 •
•w •N
•(/) •• • •
•
0 60 •
<t: • • •• •Z
.
•0
<.9 • •
• •2 40 •• • •
:J • ••2
- •
>< • • •• • •<t: • • • •2 20' • • • •• • •i
'0 • • • • •
-- •0 10
••• ••
••
• • •
• •
.1
I
.3 .. .5 I .7
TOTAL ORGANIC MATERIAL IN ·GUT(gm)
'I.~:
I
i
J
',·-r
I
i
L
100 • •
86
Figure 20~·
Relationship between gonad development and amount of organic
material in the gut o All seasons pooledo
• 1 to 10 g total calcite weight
Note change of scaleo
100 •
·
•
80 •
w
·N •(./)
••
•
•
.'
0 60 •
« •z •0 •
<.9 • •
2 40
•::J
•2
· •• • • •x • • • •
« • ••• • • •
2: 20 • • ••••0 • • •
--
••0 10 • • •• • ••
• • ••
• •.-..,.
.2 .3.1
TOTAL ORGANIC MATERIAL IN GUT(gm)
88
development limits the amount of food which can be held in the gut.
This relationship will tend to further obscure the results of feeding
estimates from field data and may be a contributing cause to the
variability of feeding rates determined from tattooed algae.
Summary of Investigation on Size and Growth
Differences in size distributions of the purple sea urchin,
Strongylocentrotus purpuratUB (Stimpson), exist locally at Sunset Bay,
Oregon. These differences generally can be accounted for by differences
in growth rates. A given size does not indicate a certain age be-
cause of the wide spectrum of growth rates and the ability of the
animals to shrink. Animals clustered around the second mode of the
size distributions are, therefore, of many age classes and there is
little hope of separating them. Possible reasons for the differences
in growth were examined in this study. Spine breakage and regenera-
tion were discarded as likely because the area with the greatest
amount of spine loss also showed the highest growth rate. Food
differences were examined; although the data are not conclusive, they
strongly suggest that differences in the amounts of food exist among
the three areas. In summer, during the maximum algal production,
animals in the boulder field take in much more food than do animals
in either of the two other areas. This apparently is the basis for
differences in the rates of growth and ultimate sizes that were ob-
served.
,89
DISCUSSION
Studies of echinoid ecology typically have delt with only one or
two aspects of the animals; no one has attempted to analyze a number
of variab1es,particular1y on a local level. A recent study by
Kawamura (1964, 1965a and b)j however, does require special mention.
A number of urchin populations are being studied and the results from
1962 through 1964 have been reported (Kawamura 1964, 1965; Kawamura
and Taki 1965). Differences in growth~ates were observed from year
to year aiong with changes in gut contents and gonad sizes. The study
does not attempt to explain observed differences or deal with popu-
lations as local as those reported in Sunset Bay. Many of Kawamura's
fid.d"~however, are in agreement with those of this study.
Growth information reported in the literature has been based on
antmals held in cages (Lewis 1958; Swan 1961; Moore ~~. 1963a and
b; McPherson 1965); aquaria (Aiyar 1935; Bull 1939; Moore ~~.
1963a and b; McPherson 1965); and size distributions (Soot-Ryen 1924;
Schorygin 1928; Grieg 1928; Elmhirst 1922, Crozi~r 1920; Moore 1935;
Moore ~~. 1963 a and b; Lewis 1958; Swan 1961; McPherson 1965;
Kawamura 1964). Only one investigator (McPherson 1965) successfully
attempted marking individuals but his method was unsuitable for
animals smaller than 6 cm. A summary of the information concerning
growth of echinoids is given in Appendix II.
As indicated above, most esti~tes of growth have been based on
positions of modes in size distributions. This tends to underestimate
the true ages of animals because, as has been shown j settling success
is not the same for every year; entire age classes can, therefore,
90
be missing. In the studies indicated in Appendix II the first few
years of growth probably are reason~bly accurately determined
especially in cases where observed for a number of years (Kawamura
1964; Lewis 1958; Moore et al. 1963a).
Laboratory studies of growth, although not giving an accurate
picture of growth in the field, give an indication of a possible rate
and longevity for the species studied. The best reported work of this
type is that of Bull (1939) on Psammechinus miZiaris, It is inter-
esting to note the apparently slow rate of growth in these aquarium
animals. At the end of 6 years, Bull's urchins were about 3,9 em
in test diameter. In the field, Lindahl and Runnstrom (1929) found
animals over 13 em. In the same area with these large animals, the
small animals showed a model class of 2,25 em. Bull's animals at the
end of one year were 2.0 em, Most of the distributions presented by
Lindahl and Runnstrom had animals over 5 or 6 em and a first mode at
about 2.0 em. It seems reasonable that the animals around 2 cm
were one year old and the possibly situations existed for Psammechinus
very similar to those in Sunset Bay for StrongyZocentrotus3 giving
rise to different rates of change in size (such as observed for
animals in the Postelsia zone and the eel grass area in Fig, 10).
Although initial growth may be quite similar in a number of areas,
ultimate sizes could be very different, This would mean that the
animals observed by Lindahl and Runnstrom (1929) mayor may not be
older than the aquarium animals of Bull. In general, the rate of
growth and apparent longevity are similar to the findings for
91
S. puPpUpatus in the present st~dy,
The work of Moore ~~~!. on Lytechinus variegatus (1963a) is a
period; however~ th.e data do not really SQPPOT, their conclusion that
Lindahl and RMnnstrom (1929) is: that;> even with the ~omplic1lltion of
different areas because of th.e shifts in the first mode from area to
A cobble bottom offshore from Imperial Beach at one
time supported a kelp area designated by the Dept. of Fish
and Game as Bed p" 1~ ~he last recorded harvest from Bed
1 was in 1939. [~onrad] Limba~gh (personal communication)
dived in the area ~bo~t ~en years ago (1953) and reported
barren ro~ks with an ab~ndan~e of young~ long~spined S.
f':t>cr.naisaanu{ifJ. North four~ ,+"" same ~onditi,::J)ns in early
1951 and little changes [siel ~ollJlld be f01.llnd when the
area was visited July 12 9 l~~Jo
92
North ~~c (1963) point out that the expected growth rate for
the small S. franoisoanus at Imperial Beach was 2 cm per year
(based on rates determined in the laboratory). In other areas studied
by this groupi animals were also small with modes for large S. pUPpur-
atus of 2 to 4 cm. Distributions of urchins in most areas had modes
of about 2.5 to .3 cm. North terms these lUurchin limited environments".
Gut contents indicated that very little food was available in the
areas. A photomicrograph published in the work shows gut contents
from an animal collected at Pt. Lama in January 1963 with only sand
and unidentifiable amorphous matter in the gut. Under low food con-
ditions~ animals move~ but they remain stationary when well fed
(North ~~. 1963). North suggests that regulation of urchin size
in the areas he and his co=workers examined may be similar to regu-
lation of size in populations of th~ gastropod Littorina (North 1954)
where there .was either environmental selection for a particular
size or animals migrated to the type of environment which~ for some
reason~ favored the particular size (North does not suggest the
possibility of growth differences). In light of the present study
it seems more likely that animals were growing very slowly in these
"urchin limitedlf areas and had a very small &eoptimumu size (corre-
sponding to the size showing zero growth in Fig. 10 of this study)o
Geographic differences are simply differences in gro~th rates and
optimal sizes.
The work with "growh zonesu is difficult to evaluate mainly
because no adequate explanation for their formation has been ad-
vanced. Deutler (1926) suggests diffelent diets during summer and
93
winter and animal migration to account for the different diets.
Moore (1937) also believed that differences in pigment deposition
could be accounted for by differences in food. The pigment Moore
discusses is echinichrome which~ structurally 8 is a naphtoquinone
(Kuhn and Wallenfels 1939)0 Echinochromes~ carotenes and xantho-
phylls are present in urchins (Fox and Scheer 1941) but no red pig-
ments related to the phycobilins of red algae. There may be a con-
nection between large amounts of food, growing 9 and producing pigment,
but it is highly doubtful that as close a relationship as Deutler
(1926)e Moore (1937) and Awerinzew (1911) suggest exists. It is
possible$ on the contrary, that starving may be associated with the
increased pigment as was found in starfish by Vevers (1949). This
pigment, of course, was not echinochrome but the phenomenon suggests
that the production of a pigment does not always have to be associat-
ed with intake of food~
Granting, however, the periodic production of echinochrome the
question is: are the results of aging studies reasonable? Examina-
tion of the growth information for the Isle of Man (Moore 1935)
based on "growth lines" in the genital plates.. indicates what appears
to be an increasing growth rate with increasing size (see Appendix 11)0
This is highly unlikely, and, if true, would be unique unless repre-
senting the beginning of a log phase of growth which in this case is
also unlikelyo
A possible explanation for the presence of echinochrome pigmen-
tation in the plate$~could be a response to minor injuryo Areas of
1i 94irritation show an increased amount of echinochrome o The urchins
that were first marked in December 1962 with pieces of vinyl
"spaghettill tubing showed increased echinochrome deposition in the
calcite meshwork underneath the plastic s1eeveso A second example of
response to injury is in the marking method presently used (Ebert
1965)0 Here& there is an accumulation of the pigment around the
monofilament inside the test~ with denser accumulations at the points
on the test where the line passes through o General observation of
animals in the field indicates that there is an accumulation around
areas of injury on the test (punctures g cracks or abrasions) 0
Echinochrome deposition in the genital plates c2~~ simply be a re-
spo~se to mild injury on the surface during stormso This would lead
to a larger number of lines in large animals and could& if large
animals were more resistant to injury (a stimulus must be greater
to elicit a response in larger animals as indicated for spine
breakage in Figo 13) account for the apparent increase in growth
rate indicated by Moore (1935)0
An age of 35 years for Colobocentrotus determined from "growth
zones" (Deutler 1926) seems somewhat high but may be correcto I do
doubt g however t that each "growth zonell in the coronal plates is
equivalent to one yearo As indicated for S purpuratus g at least
for small sizes e more than one line is deposited per year o The
results shown in Appendix II give a growth rate somewhat higher than
suggested by marked animals and do not consider shrinkage as a
possibility Which. of course g is not considered by any of the authors
mentioned 0
•.1.•.••...'fj
.:n.Jj
....;1-
95
Because a caroteno~d was suggested as responsible for the growth
lines in the plates of S puPpuratuB it is necessary to return to the
suggestion of Moore (1935), Deut1er (1926) and Awerinzew (1911)
that food is at the basis of the growth lines because, typically,
animals are not able to produce beta~carotene and must get this from
plant sources. However, according to DeNicola (1954), urchin embryos
may be able to synthesize beta-carotene. DeNicola's work,at least,
suggests the possibility that adults could also produce this product •
The point is unresolved, but periodic deposition of a substance
obviously occurs. The real question is whether it is correlated
with an annual cycle. This has not been answered by the present
study. but the problems resulting from shrinkage suggest caution in
interpretation of the lines. It is possible that they are related
to the number of times an animals has had to shrink; in which case~
lines would indicate winter conditions and major lines would be
severe conditions which might not recur every year.
A fairly constant feature of studies showing size distributions
for a number of areas is the variation in position of modes and
maximum size. McPherson (1965) shows this for Tpipneust~s ventpiao-
BUS at three localities near Miami, Florida. He suggests that this
could be due to differences in growth rates or settlement times.
His distributions for Boca Raton compared with Virginia Key show a
shift in the bimodal distributions similar to the shifts seen in the
distr~bu~ions of animals at Sunset Bay, Oregon 0 Moore (1937) shows
unimodal curves for EahinuB esauZentuB from four stations along the
/96
Brit.ish coast. He states that there "appears to be a definite
increase in the size of urchins southwards!! 0 The implication from
the work over several years at the Isle of Man is that sea water
temperature is important in determining rate of grmvth for any
particular year (Moore 1935)0 Kristensen (1951),working with cockles,
states that regional variation of size in relation to temperature
is generally slight and often not readily recognizable o Hallam
(1965),in his review of environmental causes of stunting in inverti-
brates,conc!udes that "temperature does not therefore seem to be a
particularly significant factor in stunting~ at least at the species
level.!! It is very likely that the distributions of Eahinus along
the British coast are not regulated by temperatureo
Food availability as a factor in determining growth rates has
there seems to be some question concerning food availabilityo Fox
would certainly argue against this 5 not only for urchins~ but also
A direct relationship between the growth and the period of immersion
The evidence of North et alo (1963)
~~
that this$ in fact~ was the cause fot increased growth. Subtidally,
been observed among intertidal suspension feeders such as Cardium
large organisms of the sea e
eduZe and MytiZus edulis \Kristensen 1957; Hancock and Simpson 1961)0
(time available for feeding) was observed but it was not determined
(1951) fuggests that there is more than enough food available for the
for other herbivores or opportunistic feeders.
'rne importance of food quality has been pointed out by Moore
££~< (1936b) for the growth of the gastropod NuaeZla (=Pur-pura)
97
ZapiZZus which attains a greater size on a diet of Mytilus than on
BaLanuso Similar findings were reported for the starfish Pisaste~
ochraceus in Puget Sound by Paine (1965)0 Suggestions of importance
of food quality in sea urchins have been made by Fuji (1962) and
demonstrated by Swan (1961).
It has been suggested in this study that the effect of food
availability on the urchins of Sunset Bay is to regulate the sizes
of individuals without~ apparently~ influencing the numbers of
animals. This poses the problem of what does regulate the numbers
of urchinso Predation is a possibility but is difficult to dem-
onstrateo Predators include the sunflower-star Pycnopodia
heZianthoide~ (observed eating urchins at North Cove of Cape Arago
and reported to be predators of urchins by Ricketts and Calvin (1962).
Wolf eels (Ana~hichas lupus) are cited as predators by Barsukov (1956)
and are present on the Pacific coast of North America One was seen
at Sunset Bay by a SCUBA divert John Palmer (personal communication),
but apparently they are not abundant enough to be a major factor in
controlling urchin populationso Occasionally, sea gulls were obser-
ved eating urchinso One was observed at Sunset Bay dropping an urchin
onto rocks and then coming down to eat the contentso Broken urchins
high on rocks were usually assumed, misanthropically, to have been
caused by small children of all ages o It is, however, possible that
many of these could have been from sea gulls. Gulls may, in fact,
be the major predators on intertidal populations, although local and
exotic tourists have been observed removing animals, sometimes in
'.
, ~
,
98
large numbers o This leaves the subtidal relativelv untouched exc.e~t
by Pyanopodiao I should like to propose that regulation of numbers$
for the most part~ is by physical factors acting initially on very
early stages and later excluding very large animals from high areas
either by high temperature or low oxygen tensions c These factors
would eliminate large animals durin~ times of physical extremes o
The general picture of urchin populations 'hat can be presented
from~he study of animals at Sunset ~ay is that urchins are capable
of a wide spectrum of growth rates which vary with existing physical
and biotic conditions o Animals are capable not only of increasin~ in
size tut also of shrinkingo This yields an accumulation of animals
at a size which indicates the optimal size for the set of conditions o
Animals are apparently long lived and reach ages of at least ten years
and possibly twice this o Mortality is low and~ after the first year,
population size is apparently controlled by a combination of storms,
extremes of temperature~ salinity and o~ygen tension, and low level
predationo Evidence from the literature suggests that other urchin
species may be adapted to intertidal and sublittoral conditions by
essentially the same mechanisms and controlled in the same wayso
99
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100
Crozier, W. 1920. Notes on the bionomics of Mellita. Am. Naturalist
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Jahrb.
1926. Uber das Wachstum des Seeige1ske1etts. Zool.
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I~.·~'·:!·.·. { .'fj.
'" :"1
Dixon, W. J., and F. J. Massey. 1951 Introduction to Statistical
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1(7):1-12.
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j
1
1
,!
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101
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Variation und Okologie von
10:401-484.
1935. Ibid Part II. Ibid 20:109-1280
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Akad.
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103
• 1958. Growth and variations in the sea urchins of York,
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Observations of the behavior of sea urchins.
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reproduction.
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Appendix I
Species list of algae collected from
the PosteLsia zone, the eel grass area, and the boulder
fieldo Sunset Bay, Oregon, Summer 1964 0
PosteZsia zone (Figo 2 A)
PosteZsia paiZmijo:r'l11is Ruprecht 1852
Hp~ophylZum sessile (Agardh) Setchel1 1899
·"i~::f.'tl1;iia.rti'na papill.ata Setchell 1899
Hymenena spo
corallines
Area below PosteZsia zone (Fig 2 E and F)
Costaria aostata (Turner) Saunders 1895
Cystoseira osmunaaaea (Menzies) Co Agardh 1820
Nereocystis Zuetkeana (Mertens) Pastels and Ruprecht 1840
ErythrophyZZum deZesserioides Jo Agardh 1872
Iridaea spo
Odonthalia fLoacosa (Esper) Falkenberg 1901
PtiZota spo
Ploaamium vioZaaeum Farlow 1817
LauPenaia speatabiZis Pastels and Ruprecht 1840
OpuntieZla aaliforniaa (Farlow) Kylin 1925
Pterosiphonia spo
Hymenena spo
CPyptopleura spo
corallines
104
Appendix I (cont o )
Eel grass area (Figo 2 B)
Phyllospadix torreyi Wats o
Cladophora spo
Spongomorpha sp 0
UZ?Ja spo
Monostroma zosteriaoZa Tilden 1900
Puaus furaatus Agardh
Leathesia diffoP-mis (Linne) Areschoug 1846
Soranthera uZvoidea Postels and Ruprecht 1840
Heteroahordaria abietina (Ruprecht) Setche11 and Gardner 1924
FarZ~ia moZZis (Harvely and Bailey) Farlow and Setchel1
Rhodomela LtIl'ix (Turner) Co Agardh 1822
MiaroaZadia borealis Ruprecht 1851
-Glgartina papilZata Setchell 1899
eurnagZoia andersonii (Farlow) Setche11 and Gardner 1917
OdonthaZia fZoaaosa (Esper) Falkenberg 1901
HaZosaaaion gZ,andifoP-me (Gme1in) Ruprecht 1851
I:roidaea sp~
Ceramium paaifiaum (Collins) Kylin 1925
Co eatonianum (Farlow) DeToni 1903
smithora naiadum (Anderson)
cora11ines
105
Appendix I (cancIo)
Boulder field (Fig o 2 C)
Cladophora spo
alva spo
FUcus fupcatus Agardh
HedophyZZurn sessile (Agardh) Setchell 1899
Egregia menziesii (Turner) Areschoug 1878
Bangia ve~iauZaPis Harvery 1858
Iridaea heterocarpa Postels and Ruprecht 1840
I o fZaccidum (Setchell and Gardner)
Gigarina canaZiauZata Harvey 1841
Go cristata (Setchell) Setchell and Ga~dner 1933
Go papillata Setchell 1898
OdonthaZia fZocccsa (Esper) Falkenberk 1901
l~orocladia borea~i8 Ruprecht 1851
Halosaccion gZandifor.me (Gmelin) Ruprecht 1851
Rhodamela larix (Turner) Co Agardh 1822
Ceramium eatonianum (Farlow) DeToni 1903
potysiphonia hendryi Gardner 1927
pterosiphonia spo
106
Appendix II
A summary of growth information on echinoids.
Species Location Authority Method of age Age or growth infor-
determination mation. Unless
otherwise specified,
time is in years
and size is in cen-
timeters.
CoZobooentrotus Reunion Deut1er "growth zones" an animal 6.5 cm in
stratus (1926) in the test test diameter was
judged to be 35
years old.
Eahinus Millport, E1mhirst size distri- 6 months 2 cm
esouZentus Scotland (1922) butions 1 year 4
2 4 - 7
3 7 - 9
4 9 - 11
7 - 8 15 - 16
Isle of Man, Moore size distri- 1 2.2
England. (1935) butions 2 3.4
"chickens" 3 5.2
area
"growth lines" 1 1.6
in genital 2 2.8
plates 3 4.0
4 5.5
I-'
o
.....,
Appendix II (cont.)
1IIIr.:i1i6i-~~~~·~:·~,Et''''.'1;*i;-:'f~'~7'',-,.~_·
Species Location Authority Method of age
determination
Age or growth infor-
mation. Unless
otherwise specified,
time is in years
and size is in cen-
timeters.
E. esauZentus
(cant.)
Isle of Man,
England,
breakwater
on side of
Port Erin
Bay
"growth lines"
in genital
plates
1
2
3
4
5
6
7
5.5
7.5
8.0
9.0
10.5
Lyteahinus
variegatus
MeZUta
sexies-perforata
Miami,
Florida
Bermuda
Moore ~ al.
(1963a)
Crozier
(1920)
size distri-
butions
size distri-
butions
1 5.0 - 5.5
2 7.0
normal life span
about 2 years
1 year 3.0 cm
2 6.0
3 8.0
4 10.0
normal life span
about 4 years
}-l
o
00
Appendix II (cont.)
-"' ... ;::;,
Species Location Authority Method of age
determination
Age or growth infor-
mation. Unless
otherwise specified,
time is in years
and size is in cen-
timeters.
Psammeahinus
miUaZ'is
Cu11ercoats,
Northumberland,
England
Bull
(1939)
aquaria metamor-
phosed
6 months
1 year
2
3
4
5
6
0.10
0.33
2.00
2.62
2.92
3.03
3.70
3.87
Kristineberg
Zoological
Station,
Sweden
Lindahl and
Runnstrom
(1929)
no actual deter-
minations of age
but several size
distributions are
presented
sizes that appear to
be 1 year old are:
O. 7, 0 •8, 2 •0 and
2.4 em.
SaZmaais
biaoZoZ'
TZ'ipneustes
ventY'iaosus
(=T. esauZentus)
Madras, India
Barbados,
West Indies
Federation
Aiyar
(1935)
Lewis
(1958)
aquaria
size distri-
butions and cages
3 months
6
1 year
1 year
0.4 - 0.5
1.3
1.6
5 - 8cm
I-'
o
\0
M;Y·,
Appendix II (cont.)
Species Location Authority Method of age Age or growth infor-
determination mation. Unless
otherwise specified,
time is in years
and size is in cen-
timeters.
T. ventriaosus Bimini, Moore & a1. suggest that animals
(cont.) Bermuda (1963b) in a high pool at
Bimini grow more
slowly than animals
at Barbados (Lewis
1958) because in
June the mean dia-
meter was 2.48 em
compared with 7.5
cm in Barbados
Miami, McPherson size distri- about 8 cm in one
Florida (1965) butions year
StrongyZoaentrotus New Hampshire Swan size distribu-
drobaahiensis and Maine (1961) tions 1 year 0.8 - 1.0 cm
2 2.4 - 2.6
3 4.0 - 4.2
4 4.6 - 5.4
Ramfjorde, Soot-Ryen size distribu- 1 1.2 - 2.2
Norway (1924) tions 2 2.2 - 3.3
3 3.3 - 4.0
4 4.0 - 5.2
5 5.2 - 6.0 I-'
I-'
0
Jj~~';!:;:'~:¢~*~~~<~~~~~l<~;'~t:;i4;~:;,;;'«t~~~~~~r~~1~ ..:··t.;~IiI~_~;1{~m:y;'i"", ..,.
Appendix II (cont.)
"':-
Species
S. drBbaahiensis
(cont.)
Location
Barents Sea,
U. S. S. R.
Folden and Ba1s
Fjords, Norway
Authority
Schorygin
(1928)
Grieg
(1928)
Method of age
determination
size distribu-
tions
size distribu-
tions
Age or growth infor-
mation. Unless
otherwise specified,
time is in years
and size is in cen-
timeters.
1 1.2 - 2.0
2 2.1 - 3.1
3 3.2 - 4.1
4 4.2 - 5.2
5 5.3 - 6.0
1 year 0.5 - 0.6 em
2 1.5
3 2.4 - 3.2
4 4.07
5 5.07
I-'
I-'
I-'
1;1..:.--....:..--.---- .-....
Species
S. drBbaahiensis
(cont.)
Location
Friday Harbor,
Washington
-=,-~,;;.. ",.",.=--'--_.
Appendix II (cont.)
Authority
Swan
(1961)
Method of age
determination
cages
Age or growth infor-
mation. Unless
otherwise specified,
time is in years and
size is in centi-
meters.
At beginning of ex-
periment three
groups of animals
were set up with 12,
10 and 4 individuals.
One year later 11,
9 and 1 animals re-
mained. No conclu-
sions were drawn
other than animals
at Friday Harbor
grew faster than
animals at New Hamp-
shire. Based on
Swan's growth obser-
vations the follow-
ing estimates seem
reasonable.
1 year
2 3.0 cm
3 5.6
4
5 + 7.6 I-'I-'
N
Itii..,,,., .
~z;
Appendix II (cont.)
Species
S. eahinoides
Location
Friday Harbor,
Washington
Authority
Swan
(1961)
Method of age
determination
cages
Age or growth infor-
mation. Unless
otherwise specified,
time is in years
and size is in cen-
timeters.
Three groups of an-
imals were set up
with 17, 20 and 8
individuals. One
year there were 15,
14 and 7 still alive.
The following age
classes are my esti-
mates.
1 year
2
3
4
2.6 cm
4.2
5.5
StrongyZoaentpotus
franaisaanus Friday Harbor,Washington
Swan
(1961)
cages Two size classes
were set up with 15
and 14 individuals.
After one year all
were still present.
The age class esti-
mates are mine.
1 year
2
2.9 cm
4.9
I-'
I-'
W
Appendix II (cont.)
Species Location Authority Method of age
determination
Age or growth infor-
mation. Unless
otherwise specified,
time is in years
and size is in cen-
timeters.
S. intermedius North region of
Rebun Island
on the coast
of Funadomari,
Japan
Kawamura
(1964)
size distribu-
tions
1
2
3
1.00 cm and
less
1.00 - 2.99
3.00 - 4.00
S. pUl'pul'atus Friday Harbor,
Washington
Swan
(1961)
cages Two size classes
with 2 and 12 indi-
viduals were set up.
After one year 2 and
10 remained. The
age class estimates
are mine.
1 year
2
3
1.5 em
2.6 - 3.0
4.2 - 4.6
Sunset Bay,
Oregon, high
eel grass area,
29 December 1963
This study "growth zones"
in coronal
plates
1
2
3
4
5
1.5 + 0.04 SE
2.8 + 0.02
4.0 '+ 0.56
5.1 + 0.26
6.0 + 0.24
}-J
}-J
~
.' .. -eo.« ...
Species Location
Appendix II (cont.)
Authority Method of age
determination
Age or growth infor-
mation. Unless
otherwise specified,
time is in years
and size is in cen-
timeters.
s. purpuratus
(cont. )
Sunset Bay,
Oregon, high
eel grass area,
1964-65
Sunset Bay,
Oregon,
Poste'lsia
zone, 1964-65
This study
This study
size distribu-
tions
marked animals
size distribu-
tions
1 year
2
1
2
3
4
5
6
7
8
9
10
1
2
1.62 (mode)
2.44
1.94
3.09
3.68
4.06
4.33
4.52
4.66
4.77
4.86
4.91
1.38
3.21
.....
.....
I.n
.1Itllll._;X'~1lIE:;_~;<~_'!;""""'···_·-····'·"l,-"'''.'.''''',~Y' -', I,",.' .', _:.' ." ,,'.' ", .' ,_.' • .' ".' .' .' ~•. -- .' ," - .'.'. ,,',. , .' " ,,' .' ',. ~"'''': .' .',.~~",;."·_ ...·".:. ',,.l""-~"~":"~ "~"" •.""''''''''''''''.'~'~',.,¥ ..,..... ,:...>""~'\'."'~.;"'•.. ,,.. _,.:',._ ,'1i..".,:', _.:....'~'... ,... ,.,' ...'_. _ :", .,.•.. _', .' ~.- ,,:'-, , .. ,?07sv.......,. .. ,...-. .'.' ,,','fO, .'.' ~,~.~JftI,~.:.;;!(,"",.•\~.' .. ,.,~...
Appendix II (concluded)
Species Location Authority Method of age
determination
Age or growth infor-
mation. Unless
otherwise specified,
time is in years
and size is in cen-
timeters.
S. puppuratus
(cont.)
Sunset Bay,
Oregon,
PosteZsia
zone, 1964-65
(cont.)
boulder field,
1964-65
eel grass area,
1964-65
This Study marked animals 1 0.95
2 1. 76
3 2.36
4 2.78
5 3.09
6 3.34
7 3.54
graphic method 1 2.95
which assumes 2 4.26
that the first 3 5.02
mode of the 1964 4 5.53
size distribution 5 5.89
is 1-year's growth 6 6.15
and the second mode 7 6.35
is the point of 8 6.50
zero growth 9 6.61
10 6.69
determined by the 1 1.62
graphic method 2 2.76
explained above 3 3.38
4 3.80
5 4.10
6 4.33
7 4.51 ~~
8 4.65 0\
9 4.76
10 4.85

118
Appendix III (cont.)
PosteZsia Zone (cont, )
Date CaC03 sand Date CaC03 sand Date
CaCO sand
3
! ~ 7-65 013 '* 000 10-65 036 .091 ~.~
~i~- 1014 .14 .23 .38,1 ~!I
.79 ,24 013 '* .03
032 .00 .50 021
.30 .02
'*
006 .06
'*
.13 .07 .62 .31
.32
'*
032
'*
.64 009
.72 .23 .23
'*
.50
.59 .21 .28 .43
*1037 .17 .21 .13
Eel Grass Area
9-64 *1.00 021 11-64 .23 .34 1-65 *1060 .30
.03 .15 * .00 .15 .39 .28
'*
.00 * .00 .40 '* .00 * .13 .69
.60 .04 *1005 .24 1.03 .28
.00 002 035 006 1019 .44
.40 ,25 .78 * .78 .33 *7.07
.10 023 .42 .48 .80 * .20
.29 .08 .17 .11 .33 1033
.40
'*
.32 .05 .26
.02 .06
119
Appendix III (canto)
Eel Grass Area (canto)
Date CaC03 sand Date CaC03 sand Date CaC03 sand
3-65 018 041 4-65 032 022 6-65 * 000 009
021 021 050 040 002 012
* 052 LOO 017 069 .01 .03
.10 *L35 048 .19 006 004
.. 000 * 000 .08 032 .03 004
017 028 * 008 * 008 0'00 .. .00
033 033 059 .24 .. .08 * .18
044 056 029 029 005 .09
.25 .25 .53 .47 000 . 000
035 035 * .86 *1.98
7=65 .. .00 012 10-65 008 020
000 004 020 .27
.00 .0 .29 if 019
000 if 000 024 if 090
023 if 015 if .31 .38
007 .07 021 .36
.00 008 .. .00 043
000 .00 .05 040
000 011 000 .75
* .35 .12
120
Appendix III (cant.)
Boulder Field
Date CaC0 3 sand Date CaC0 3 sand Date CaC0 3 sand
9-64 * .03 .15 11-64 * .00 * .00 1-65 .03 .26
.03 * .02 .02 * .16 .00 .37
* .00 .04 .00 .03 .00 .27
.02 * .17 .04 .09 .00 * .05
.02 .07 .00 .10
* .04 .08 .08 .50
.00 .53
..
.00 .09
.11 .67
.03 * .90
.31
3-65 * .00 * .05 4-65 .09 .27 6-65 .01 .01
.40 .40 .02 * .03 .04 * .00
.24 .42 .09 *1.04 .03 .01
* .95 * .57 .01 .14 .03 * .13
.18 .35 .10 .73 .02 .00
.05 .19 .01 .05 .01 .00
.26 .30 * .00 .05 .09 .00
.02 .15 .03 .16 * .00 .00
.02 .15 * .16 .18 * .09 .09
.21 .29 .04 .39 .03 .05
121
Appendix III (conel.)
Boulder Field (cancIo)
Date CaC03 san(: 1'" CaC03 sand Date CaC03 sa'l'd
7-65 ,01 * .00 10-65 * .08 * .00
,00 .01
*
.00 .04
* cOO 002 000 * c21
cOO 001 cOS .10
cOO
*
.05 001 .03
.00 .00 .01 012
* .33 .04 .03 .10
•
cOO .03 002 010
000 000 .02 .19
.00 000 .00 .03
122
Appendix IV
Algae held by samples of urchins in five areas at Sunset Bay.
All weights are in grams.
Boulder field, 29 July 1965 Size distribution shown in Fig. 9 vi.
Number of animals in sample = 176, wet weight = 18,103,
mean = 102.8 g.
Species
Red algae
Iridaea Spa
Gigartina Spa
(mainly G. papilZata
Rhodomela Zari:J:
OdonthaZia fZocoosa
Po:rrphyra Spe
CPyptopZeura Spe )
)-
Irnodomenia Spe '
Ceramium sp e )
)
Pteroohondria 'lJoodii )
)
EndoaZadia muriaata )
)
Ploaamium Spe )-
)
Pterosiphonia Spe )
)
ptilota Spe )
)
Laurenaia speatabiZis )
Brown algae
Fuaus fUl'aatus
Hedophyllum sessile
Wet weight
173.53
129.79
12.34
9.70
2 e 68
4e 71
150.35
22.55
Dry weight
36.75
30.74
2.37
1.91
0.35
0.39
0.30
31.09
3.10
Appendix IV (canto)
Boulder f ielA~39 .Jul.Y.1.9.tl5. (cant.)
123
Species
Brown algae (conto)
AZaria va Zida
Eareaia menziesii
OJ v
Desmarestia sp. )
)
Cystoseira osmundacea )
)
Soranthera ulvoidea )~
)
Heteroehordaria abietina )
)
Scytosiphon lomentaria )
Green algae
UZva sp.
Cladophora sp.
Diatoms
mainly Navicula sp.
Angiosperms
PhylZospadix torreyi
Total weight
~el grass ar~at 30 July 1965
Het \veight
12.65
6.50
1.19
51 0 25
1.69
606.84 g
Dry weight
0.83
0.17
9.96
0.50
0.48
5.40
126.61 g
Number of animals in sample = 104, wet weight = 3,412,
mean = 32.8 g.
Red algae
Gigartina papiZZata 0.80
Appendix IV (cant.)
Eel grass area, 30 JulI 1965$(cont.)
124
Species
Red algae (cont.)
Wet weight Dry weight
Rhodome Za larix 2.34 0.50
Coralline algae 1.87 0.95
I:l'idaea sp. 0.78 0.23
BrOl,m algae
Fueme furaatus 15.64 3.68
Hedophyllum sessile )
)- 0.48 0.08
Soranthera ulvoidea )
Green algae
aLva sp. 16.13 3.71
Spongomorpha Spe 2.77 1.02
Cladophora ap. 2.02 0.83
Angiosperms
PhyZZospadi:x: torregi 1.57 0.40
Animals
3 crabs
1 large Pugettia sp. )
1 small Pugettia Spa )- 6A91 2.14
1 small Hemigrapsus sp. )
Total weight 53.63 g 14.46 g
125
Appendix IV (cont o)
Number of animals iil saq>le 50 70. wet weight,.. 31>397.
mean'" 48 0 5 go
Species
Red algae
HymBnena spo
Brown algae
HedOphyZZum s~s8iZe
Misco algae and angiosperms
Gigartina spo
P"loaamium sp 0
Ectoaarpus spo
PhyZZospadi:r: to:t'l'eyi
Total weight
)
)
)
)~
)
)
)
loJet weight Dry weight
Ar~a below.£he PosteZsia zone and no~tht ~9 J~ly 196~~ size distri-
bution shown in Figo 9 viiio Number of animals in sample = 122.
wet weight,.. 8,438, mean • 6901 go
Red algae
Iridaea spo 10016 1096
C:royptopZeura spo 9076 2047
PoZyneul'a spo 7084 2000
OpuntieZZa aaZiforniaa 6074 1086
PZoaamium sp 0 1042 0015
126
Appendix IV (conto)
Are,a beAo,:q~,tp.e Postel.si:,a zone and north" 29 Aulx 1~6,5. (conto~,
Species t-let weight Dry weight
Red algae (conto)
EPyth'l"ophy l.l.VPI de lesseFioides )
)
Constantinea simpZe:c )~ 0086
)
PoZysiphonia spo )
Brown algae
Hedophy ZZVPI ?
cystoseira osmundaaea
Misc. algae
Diatoms
Fuaus furaatus
ll'lva Spa
Angiosperms
PhyZlospadix tor'l"eyi
Total weight
)
)
)-
)
)
1.54
O~Q,
44 0 80
0.31
0.17
0,.23
9.95
Area below the PosteZsia zo~e ~nd soutp~ 29 Ju1X 1965 L size distri-
bution shown in Fig. 9 vii. Number of animals in sample = 104.
wet weight = 7;571, mean = 72.8 g.
Read algae
Iridaea spo
CPyptopZeura spo
Mioroaladia borealis
46.29
4.18
10.00
0.87
Appendi~ IV (conte)
127
Species Wet weight Dry weight
Red algae~ (conte)
OpuntieUa aalifomica 2 0 62 0 0 94
I Coralline algae 1,32 0 0 82
I RhodomeZa Z( rix 0.84 0,24
Pol.yneul'CI. apo )
)
OdonthaZia sp. )= 0.30 0 0 17
)
Folysiphonia spo )
Brown algae
~ql'egia menziesii 128 0 02 15.82
i:-1isco algae
Po;[":ohu:r>(J spo )< •
)~ 0030 0 0 09
Ulva sp" )
Angiospems
?hy Llospadi:t: topreyi =o~~e~~&e 0 0 52.utl~ao::ut! I
Total weight 191056 30.99
L
1,
Appendix IV (cont.)
128
I
i
1
,I
:I
;1
I
"'
I
Boulder field, 4 March 1966
Number of animals in sample 34, wet weight 4,007,
mean = 117.9 g.
Species Wet weight Dry weight
Red algae
Gigal'ina sp. )
)- 0.26
Phol'phYl'a sp. )
Misc.
Bryozoan 0.03
Hydroid (mainly
chitinous material) 0.56
Total weight 0.85 g
Eel grass area 4 March 1966
Number of animals in sample = 49, wet weight = 1,563,
mean 31. 9 g.
approx. 99% PhyZZospadix L 0.301% POl'phYl'a sp. and UZva sp. )
Total weight 0.30
PosteZsia zone, 4 March 1966
Number of animals in sample
mean = 45.5 g.
Red algae
Coralline algae
42, wet weight = 1,913,
0.04
Appendix IV (concluded)
EosteZsia zone, 4 March 1966 (conte)
Misc o
approx o 90% dead PhyZZospadix )
10% Iridaea Spe ~ live PhyZZospadix" L
Pterosiphonia sp 0 t and Sahizymenia ? )
or DiZsea ? )
Total weight 0015
129
Ii"
Appendix V
'1r'... ~ .:..::.;~~.;
Effect of marking on growth of the test, The statistic ~d is the change in test diameter without
respect to area, time of measurement or original diameter. Original diameter in centimeters is do and
the diameter after a variable time period of from two months to one year is do. Time is most variable
l.
for intermediate values of ~d. At the extremes of growth (greatest shrinkage and greatest increase)
time is mainly one year. Most means are from five measurements. Animals less than 2.00 cm were
usually measured only three times; therefore, comparisons of standard errors of animals less than 2.00
cm with animals larger than 2.00 cm will give conservative estimates of difference.
d d i0
Mean ± SE Mean ± SE
5.54 + .014 5.53 ± .005
5.42 ,013 5.37 .019
2.93 .015 2.90 .005
4.96 .009 4.91 .015
5.17 .015 5,07 .013
~d
-.30 to -.21
MEAN
do do ~dl.
Mean ± SE Mean ± SE
5.47 ± .029 5.24 ± .009 -.10 to -.01
4,92 .018 4.71 .011
6,15 .019 5.84 .009
6.53 .046 6.24 .009
6.35 .019 6.10 .007
5.29 ,015 5.08 .020
5.79 .024 5.54 ,011 4.80 .017 4,76 .011 i-'
W
o
tAppendix V (cont.)
~d do di ~d do do:I.
Mean + SE Mean ± SE Mean + SE Mean + SE
+.10 to +.19 1.88 + .004 2.06 + .008 +.30 to .39 4.67 + .008 4.97 ± .010
5.81 .009 5.93 .021 1. 79 .003 2.11 .007
4.87 .012 4.97 .010 3.79 .006 4.14 .011
3.91 .004 4.08 .009 4.05 .033 4.39 .044
5.15 .010 5.30 .019 1.91 .015 2.23 .005
MEAN 4.32 .008 4.47 .012 3.24 .013 3.57 .007
- - - -
+.50 to .59 2.82 .009 3.40 .017 +.70 to .79 1.91 .011 2.62 .008
2.59 .006 3.14 .010 1.54 .003 2.26 .016
4.91 .005 5.44 .012 2.37 .003 3.11 .007
2.49 .017 2.99 .022 1. 79 .005 2.53 .013
1.92 .008 2.49 .010 2.51 .029 3.25 .031
MEAN 2.95 .009 3.49 .014 2.02 .010 2.75 .015
I-'
w
I-'
Appendix V (cont.)
lid do d i lid do d·1.
Mean + SE Mean + SE Mean + SE Mean + SE
+.90 to 1.09 1.57 + .002 2.51 ± .029 1.30 to 10 79 1. 77 ± .008 3.13 + 0015
2.02 .009 2.93 .032 1.22 .008 2.67 .029
1.90 .005 2.86 .015 1.50 .020 3.29 .020
1.89 .010 2.92 .027 2.20 .012 3.52 .035
1.93 .037 2.94 .014 1046 0007 3.23 .009
MEAN 1.86 .013 2.83 .023 1.63 .Oll 3.17 .022
I-'
W
N
Appendix V (concluded)
Growth of three animals from the eel grass area with three to five measurements in centimeters for
each date. * indicates the diameter with the marked ambulacrum.
~ Date
-...., 7-64 12-64 7-65 11-65 3-66
Animal ...................
1.57, 1.56 2.53, 2.55 ~~3.12, 3.31 *3.57, 3.74 ~~3.57, 3.77
1 1.57 2.48, 2.49 3.24, 3.29 3.66, 3.69 3.68, 3.72
3.29 3.68 3.72
1.78,1.76 *2.85, 2.96 *3.20, 3.35
2 1. 78 2.89, 2.95 3.24, 3.25
2.97 3.34
1.91, 1.94 2.52, 2.49 *3.31, 3.37 *3.79, 3.97 ~~3.85, 3.93
3 1.91 2.51, 2.46 3.26, 3.35 3.96, 3.82 3.92, 3.87
2.48 3.37 3.92 3.96
J-l
W
W
i
I
i
I
i
I
I
Typed By: IIP-4- i.1'~~".'"
(Sadri Secretarial Service)