DISTRIEUTION
(Embistecidae) IM THEF
OF FOINT CAERIL
ic
Marine
Stanferd University
AESTRACT
Io examine what factors influence surfperch distribution
and behavier, I made cbservations of a protected nearshore
area off Foint Cabrille, California at different times of the
day and tidal cycle. Within the study area, there was
substantial niche diversity in the members of the family
The
Embictecidae ameng different habitats of similar depths.
black surfperch were found in the most pretected area of the
study and in highest densities at low tide. The striped and
pile surfperch were equal in abundance in all habitats. The
rainbow surfperch were seen in small schoels on sandy
bottoms. The reef surfperch were the mest abundant species
of Embictocid: they inhabited a shallew nearshere region and
concentrated in large schools at the entrances to channels
during low tides.
Niche diversification seems to be a relevant way of
viewing dynamic fish distributions and an important factor to
be considered in choosing methods for conducting pepulation
studies.
INTRODUCTIOM
Embictocidae (surfperch) is a viviparcus fish family
found only in the North Facific and fairly abundantly in
Menterey Bay. A diverse population occurs in the protected
nearshore area of Feint Cabrille. As with other viviparcus
animals, the young are nurtured internally by their mather.
These fish have a gestation peried of appeximately five te
six months (Eurgess and Axelrod 1984), ending in the
springtime. Live-bearing is an evolutionary adaptation to
reduce early direct mertalitys thausands less eggs are
fertilized yearly.
Behavioral and dietary studies have been conducted in on
tuo congeneric species, Ex jacksomi and E. lateralis. Hixen
(1980) ebserved competitive interactions between the twe
species in Santa Barbara and found the striped surfperch to
be the dominant competiter aver the shallew algas-covered
reef, leaving the black surfperch te forage aver deeper turf.
Similar studies at Hepkins Marine Station hy Tom (1988)
reported that the black and striped surfperch there share
their available prey rescurces and de not differ
significantly in distributien.
Observations made by Nichels (1979) of the surfperch in
a 20 square meter transect in the same area as my study
reported sharpnese and shiner surfperch, beth found in
schools, to be the most abundant Embictocids, follewed by
pile, black striped, and calico surfperch. A personal
communigation by C. Baster reported large schoels of shiner
surfperch from 1974 to 1988 and an abundance of dvarf
surfperch from 1985 tc 1987.
MOTERTALS AMD METHODS
From May 15 te June 3, 1989, I made cbservations of the
distribution and behavier of the Embictocidae in a 3800
square meter section of the protected nearshore zone at Faint
Cabrille, California (see figure 1). I used sporkeling and
cccasicnally SCUBe diving gear and recorded my counts and
observations on underwater paper. Observations were
conducted at different times during the day and tidal cycie.
The study area was divided into five separate habitats: the
time spent in each was recorded and vemained fairly constant
for each respective area. A strüctured pattern was follewed
on each snorkel survey in order to aveid as much repetitive
counting oft individuals as possible.
Habitat A (370 square meters), the area under and arcund
the railroad tracks, is very well-protected from surge and
breaking waves by Seal Rocks. Ehyilospadix covers the
shallow intertidal area of the tracksi algae grows all over
the submerged tracks and ties which are approximately one
foot above the sandy bottom. The area slepes down to a depth
of 10-15 feet, where the tracks end and a small grove of
Macregystis begins. I usually spent 15 minutes here.
Habitat B (1600 square meters), the area protected by
Seal Rocks, is marked on its southern boundary by a sand
channel. The bottom is characterized by medium-sized and
large rocks, thick Ehyllospadix, and sandy patches. Other
than the sandy, shallow area near the shore, the approximate
depth of this habitat ranges from 4 to 8 feet. Surge is
greater in this area than at the railread tracks, but rarely
strong. This is a popular swimming area for harber seals.
My cbservation time here was abcut 30 minutes.
C
Habitat C (530 square meters) is the relatively
unprotected area between Seal and Bird Rocks. Surge and
suell increase fairly dramatically as one moves inte this
habitat; waves are often breaking just seuth of Eird Rocks.
The depth here is 10 to is feets it contains the sparse edges
of the kelp forest and some Ehyllespadix covered rocks. I
spent 10 minutes observing this area.
Habitat D4(730 square meters), the ares protected by
Eird Rocks, is marked en its southern beundary by Fete's
Rock. It is a shallow area of approwimately 5 feet in depth
with parts being too shallou to sporkel at low tide. The
bottom of the southern side is light-colored and sandy, while
Ehyllespadig grous thickly in the northern section. Although
this habitat is protected from breaking waves, the water
currents can be very strong as the water moves through the
channel in one direction to the seuth. Observation time here
ranged from 10 to 15 minutes.
Habitat E (570 square meters) is the channel beyend Bird
Rocks that leads into a more exposed section af Monterey Bay.
Ehyllespadik'is heavy, but as the area sicpes down to its
maximum depth of 15 feet, the surfgrass divides to line the
edges of the sandy channel. The channel cpens up onte sone
scattered Macrscystis plants which mark the end of my stud,
area. This is the mest vielent water of my study: water
rushes between the rocks at high speeds, the surge and swell
are very large, and waves are often breaking at the mouth of
the channel. There is a small, more shallow and protected
area on the west side of section E near the shore. I
cbserved in this channel for approwimately 10 minutes.
RESULTS
Threugheut the entire study, I saw a total of li species
of Embictocids (see table 1), five of which were abundant
encugh for me to hypothesize about their distribution. These
five species (the black, striped, pile, rainbow, and reef
surfperches) and their average densities in the entire study
area are presented in figure 2.
The average densities of each species in each habitat
are shoun in figure 3. The large variations display that the
five diverse habitats contain very different distributions af
surfperch, indicating considerable niche diversity among the
Embictocids of this region. The graph of percent abundance
(figure 4) shows the habitat(s) in which each species seems
mest successful er brefers to live.
The results are presented separately for each of the
major species. Tables a through 7 list the complete data
from each habitat.
Rlack Surfperch (Embigtsga jagksoni)
Altheuch the black surfperch were the fourth mest dense
in the entire study area, they had by far the greatest
density of any fish in any habitat when found beneath the
railread tracks. Likewise, the protected area under the
tracks was the enly habitat in which their density was
substantial. As the habitats became rougher and less
protected, their respective densities seemed to decrease.
An interesting and statistically significant correlation
was discovered between the number of black surfperch under
the railroad tracks and the height of the tide. (See figure
5) Os the tide rises, the number of Ex iacksani beneath the
tracks decreases.
I usually found these fish concentrated in tight groups
of abeut 15 under each of the algae covered railread ties and
maintaining a pacing behavior back and forth to either side
of the ties. Alang with the relatively calm water in this
habitat, the tracks seemed to afford these perch a protected
area and a large, open, horizontal plame of water to inhabit.
They were all adults (20 to 30 cm in length): I once saw a
large black chase a smaller black from beneath a railroad
tie. I recognized four pregnant females and one juvenile.1
witnessed black surfperch feeding both by picking and
winnewing. On seven sightings threughout the study I
cbserved Ex iacksoni moving in odd manners: quivering and
flipping to one side seemingly scratching their dorsal fins.
Interestingly, I sau higher numbers of black surfperch
than usual in the ares protected by seal recks during my two
nicht snorkels. They seamed less active nocturnally than any
other species.
Striped Sumfperch (Embiotoca late
5)
The second most dense species in the entire study area,
the striped surfperch,, were consistently dense in each
habitat and correlated closely in their density and abundance
te that of the pile surfperch. They were mest dense in the
channel beyand Bird Rocks follewed by the ares between Bird
and Seal Rocks: the twe most expesed habitats in the study.
Interestingly, 507 and 457 of the Ex lateralis found in those
respective regions were juveriles.
This species' nest mest dense habitat was beneath the
railroad tracks with their congeneric species, the black
perch. The bighest density, of pregnant fish were the striped
surfperch cbserved ih this areat 457 of them were visibly
pregnant. Because of an injury which marked her, one
pregnant striped surfperch was seen swimming under the same
railroad tie on four separate shorkels which spanned three
consecutive days.
A påttern that seemed to emerge but did not vield
statistically significant evidence was that as my study
period passed, the number of pregnant striped decreased and
the number of juvenile striped increased. I saw very feu
pregnant or young-of-the-year fish of other species in
comparison to the numbers I saw of E. lateralis. I seem to
have witnessed the end of the striped sürfperch's five- to
six-menth gestation pericd.
I cheerved on at least seven occassions a pregnant
striped surfperch with an injury such as a bloody gash in its
musculature. The juveniles often traveled in schools of
approximately 10. I witnessed striped surfperch feeding both
by picking and winnewing. Oddly, near the end ofmy study
period I began to natice many striped perch that seemed very
light in coler or bleached out.. I once noted a harbor seal
chasing an E. lateralis.
Eile Surfperch (Damalichthys vacca)
The pile and the striped surfperch were consistently
similar in density and abundance throughout the study area.
Like the striped, pile surfperch were found to be most dense
in the twe mest exposed habitats: between Bird and Seal
Rocks and the channel beyond Bird Rocks. Next, they were
observed in almost identical density as E. lateralis in the
area protected by Seal Rocks. I observed less pile than
striped in the railroad tracks habitat and a different
behavior: the pile were seen mainly as individuals swimming
around the railroad track area as opposed to beneath the
tracks.
The pile surfperch were the most dense fish seen in the
habitat protected by Bird Rocks, the area which contained by
far the lowest numbers of surfperch. D. Vacca, as well as E.
lateralis, seemed to thrive primarily in the rough, exposed
areas but.able te live successfully throughout the study
area.
The pile surfperch often swam in small groupsiof five to
fifteen. I cbserved four juvenile and tuc pregnant pile
surfperch.
Haimbow Surfperch (Hypsurus carvil
The rainbew surfperch were the lesst dense of the five
primary Embictocids in the study area. They wereichserved in
greatest density in the exposed habitat between Eird and Seal
Recks in scheols of 10 to 20 on the sandy botton. The same
behavior was observed in the area arcund the railroad tracks
and en the scuth edge of the Seal Rocks habitat gnithe border
of the sand channel. I often observed rainbow surfperch
feeding by picking at the algal turf of the sandy ocean
floor. H. Carvi were rarely seen cutside of their schools as
individuals. I chserved two noticably pregnant rainbew
surfperch.
Reef Sunfperch (Micrometrus aurera)
The most dense Embictocid in the entire study ares was
seen primarily in the area protected by Seal Rocks. A
statistically significant correlation was found between the
number of reef surfperch in this habitat and the height of
the tide: the lower the tide, the greater the number of fish
inhabiting this area. (See figure 6) During leu tides, the
reef surfperch were observed in large scheols of 50 to 100 in
the shallew, sandy, nearshore section. Saveral times I
noticed the presence of these schools while standing on the
rocks nest to the water at lew tide.
The ather fairly abundant appearance the reef surfperch
made was in the channel beyend Bird Rocks. Here, they
appeared in the more protected section of the channel. In
this habitat as well in frent of Seal Rocks they seemed to be
more abundant at low tides. (See figure 7) Altheugh the
correlation is not statistically significant in the channel,
the data suggests a trend that I believe would be supported
by more ebservations.
DISCUSSION
The great variatign in densities of different species in
varicus habitsts displays the existence of niche diversity
among the five co-occurring Embictocidae species in the
stüdy. The protected nearshore zone contains a dynamic
population of surfperch, the patterns and distributions of
which are not always ebvious from casual observatign.
The black surfperch showed a clear abundance in the
prttected area beneath the railroad tracks during low tide.
They seemite be less successful in rough, exposed areas.
Eventheugh I have been SCUEO diving and srerkeling in all
areas of immediate prowimity to the railroad tracks, Iam
baffled by the question of these black surfperch's habitat
during high tide. I think that more distribution studies of
the greater surrounding area would be revealing.
Eoth the striped and the pile surfperch appeared to be
mest successful in the mest esposed habitats altheugh these
tue species, more than any ather, were relatively everly
distributed threugheut the study area. The strong
correlation of these fish seems interesting not only because
that trend has not been reported in other areas or at Foint
Cabrille before, but alse because these two species have
significantly different diets. While the striped surfperch
feed from the algal turf, the pile surfperch appear to be
selective visual feeders on larger spails and hermit crabs.
(Nichols 1979) This separation apparently permits them to
expleit their respective rescurces witheut competition.
The rainbou surfperch, though nat as abundant as the
ether four species, ware consistently found in small schools
on sandy bottoms in depths of ten or more feet. Although
they did not tecur in the exposed channeli past Eird Rocks
which dees have a sandy bottom, they appeared to be
successful in the rough but less-exposed area between Bird
and Seal Rocks. Ferhaps the rainbow surfperch can live
successfully in schools en any sandy bettom se leng as the
surge or reugh water is under some critical point.
The mest dynamic pepulation af Embistecids was the reaf
surfperch: depending on the height of the tide, their
numbers ranged from zero to 250. Figure é suggests that
there could exist same critical tidal level such as 1.5 feet
under which the large schools of reef are always in the Seal
Rocks habitat. As with the black perch, I have anly
speculative insight inte the high-tide habitat of the
Migrometrus auroras they could be broadly spread through the
complen rocky shallow water habitat.
Accerding te the personal. observations of Chuck. Baxter,
large schools of dwarf surfperch (Micrometrus mininus,
congener of the reef surfperch) inhabited the nearshore zone
off of Feint Cabrille from 1985 to 1987. He also reported
similar large schools of shiner surfperch, related in size
and appearance to the reef surfperch, from 1974 to 1983.
This spring, I cbserved very few individuals of those two
species: estreme annual variaticn is gecurring among the
populatiens of smaller surfperch.' Future cbservations of the
What
present schoels of reef surfperch would be interesting.
are the seasonal and yearly patterns of their population
structures to there de they relccate; scheols of which, if
any, species will replace them?, De emmigration and
immigration play a large rele in structuring these
pepulatiens or are they dependent on the dynamies from
reproductive recruitment? The unique life cycle of the
Embietocids, which includes the viviparous production of
advanced juveniles, makes their population dynamics an
interesting comparison to that of other resident species.
Observations or habitat manipulations could be conducted in
order to determine what factors dictate these yearly
variations of high magnitudes.
The results concerning the reef and the black surfperch
display that the tidal height is a significant variable
affecting at least two of the surfperch populations in my
study area. I found ne conclusive distributicnal effect af
the time of the day, but because of my low numbers of night¬
time cbservations, still believe that the ammeunt of light
cculd have and effect on surfperch distribution.
Figure 5 presents the density change of Embictecids aver
one decade by comparing the average densities that I observed
with these recorded in 1979 in another study of a transect in
0
the same regich (Nichols 1979). Whereas the density af black
surfperch seems to have remained constant, the densities of
striped and pile surfperch have increased substantially while
remaining generally consistent with each other. Neither the
rainbow nor the schools of reef surfperch were observed in
the transect in 1979: it seems that large schools of shiner
and sharpnose surfperch were'seen instead. This data
cerrelates with the Baxter observations of schools of shiner
perch in the study area over the last fifteen years, while
this year it seems that few individuals remain. Nichels alse
reported scheols of sharpnose surfperch and some appearance
of calice surfperch, neither of which species seem to exist
aff of Feint Cabrillo this spring. It is interesting that
the shiner and sharpnose perch bear size, shape, and some
dietary similarities to the reef surfperch and
Correspondingly, the rainbew and calico perch share size and
pattern characteristics.
Nichols' data showed ancther interesting decadal
variation that at the same time of year in 1979, larger
densities of black and pile juveniles were observed than
striped juveniles. (Nichols 1979) This comparisch is
contradictory to my observations of large numbers of striped
juveniles in 1987. (See figure 9)
Eecause the number of pregnant striped decreased and the
number of ycung-of-the-year striped increased as my study
progressed, I believe that I witnessed a critical peint: the
end of E. lateralis' five- to six-menth gestation period.
The lack af literature reporting any conclusive dates of the
c
beginnings and ends of the different species' gestation
perieds made my theery difficult te cenfirm. Nichols
observations as they relate to my data suggest that gestation
does not occur at precisely regular intervals each year, but
rather may be dependent on weather, temperature, er ether
seasonal variables. Consecutive annual spring ebservations
could yield a clearer picture of variability of gestation
periods.
Intuitively, it seems that in order to bensfit from
their avelutjomal adaptation of viviparity and to pretect
their small yearly batch of fertilized eggs, the pregnant
female surfperch weuld be required te change their behavicr
during the conclusion of their gestaticn period. The ventral
sides of the pregnant surfperch I chserved were ehvieusly
distended and lighter in coler than the rest of their bedy:
at this hlcated period they were inevitably less hydrodynamig
than usdal, Therefore, it seems appropriate that the
pregnant striped surfperch eccured mest densely in the most
protected habitat in my study: the railroad tracks. The
comparitively high numbers of injured pregnant Exlateralis
suggests either that these pregnant perch cannot swim as well
as their lithe geunterparts, that the bleated fish are more
attractive to their predators, er both of these hypotheses.
One suprising result was the different distributions of
the twe congeners, E. iacksoni and E. lateralis, in
different habitats with approkimately the same depth.
According to Hixen (1980), competition is the cause of these
c
tuo species' segregation by depth in Santa Earbara,
California. There, Ex lateralis dominates the shallow, more
desirable reef, pushing Ex iscksoni inte deeper water. From
recent studies at Hepkins by Tom (1788), the black and
striped surfperch off of Foint Cabrille shared an identical
fesding niche and did not differ significantly in
distribution. My cbservations revealed that the two species
were significantly differently distributed aver a lateral
area of similar depths. Combining the gut analysis from Tom
(1988) and my results, these twe fish are eating similarly in
different places: factors other than food preference are
determining their habitat cheice.
The differing results that Tom (1988) and I found could
indicate the differences in cur methods of cbservation and
perspectives on cur respective transects. Her observatiomal
esperiment was done by cbserving a quadrat of one continuous
habitat. This comparison demonstrates clearly that the
cheice of transect and method of analyzing it dees affect the
results of a transect experiment. The niche diversity thåt I
cbserved, specifically among the black and striped surfperch,
displays that different potential transects which, from
initial observations, lock very similar, in fact have very
different surfperch populations.
One inevitable concern of observational studies is the
cloudiness that surrounds the effect of the observer on the
behavier of the subjects. I can only hope that I scared all
species away in equal proportions so that my ratios have
remained consistent. The fish did not seem daunted by my
presences when I was SCUBe diving and cculd lie en the bettem
relatively meticnless, surfperch came within centimeters of
me, Gnother concern is the effect of the harbor seals on the
number of fish that I saw. In the area in front of Seal
Rocks, seals regularly follewed me, surrounded ne, and
generally demanded my attention as I attempted to observe and
count Embictocids. Mest fish did not seem too distürbed and
I continually found high pumbers of fish in this habitat.
Tuc other hinderances of my Vision were the often poor
visibility in the water and the excessive presence'af
phyllespadis, meither of which varied significantly.
C
BIELIOGRAFHY
Baltz, Donald M. and Moyle, Feter B. 1982. Life history
characteristics of tule perch (Hysterecarpus traski
pepulations in centrasting envirenments. Env. Biel.
Fish. Vol. 7, No. 3, pp. 229-242.
Behrens, David W. 1977. Fecundity and reproduction of the
viviparous perches Hypsurus caryi (Ogassiz) and
Embiotoca jacksoni Agassiz. Calif. Fish and Game
63(4): 234-252.
Eurgess, Dr. Warren C. and Axelred, Dr. Herbert R., 1784,
ishes of California and Western Mexice, Facific Marine
Fishes, Book 8, T. F. H. Fublications, Inc. Ltd., pp.
2oa9-2039.
DeMartini, Edward E., Moore, Thomas O., and Plummer, Kenneth
M. 1783. Repreductive and growth dynamics of
Hymærpreschen ardentem (Embictocidae) near San Diege,
California. Env. Biel. Fish. Vol. 8. No. 1, pp.29-38.
Mark A. 1980. Competitive interactions between
Hixon,
California reef fishes of the Genus Embictoca. Ecology
61(4): 918-931.
Mark A. 1981. An experimental analysis of
Hixon,
territoriality in the California reef fish Embigtega
jacksani
(Embictocidae). Copeia 1981(3): 453-
665.
Laur
David R. and Ebeling, Alfred W. 1783. Fredator-prey
brelationships in surfperches. Env. Biel. Fish. Vol. 8. No.
3/4, pp. 217-229.
Nichols, Andrew W. Spring 1979. Fredation by tidepcol,and
nearshore fishes and its impact on the rocky intertidal
zone
community.
Tiffany W. C. May 1988. A regional absense of
Tom,
competition between congeneric surfperch sharing the
same dietary preferences and spatial distribution. M.
S. Thesis.
Common
81 ac
Striped
Pile
Hainbow
Reef
Duarf
Shiner
Barred
Silzer
Kelp
Rubberlip
SPECIES OF EMBIOTOCIDAE OBSERVED IN STUDY AREA
Scientific
Embiotoca jacksen.
Embiotoca lateralis
Damalichths vacca
a
Hicrometrus aurora
Nierometrus minimus
Cmataste a
Aphistichus argente
Hyperpresopon elliptiu
Brachyistius frenat
Hhaochilus touotes
Table!
HABITAT A: UNDER THE RAILROAD TRACKS

tidal

2
8
date time level
15-1 1515
15-2 1545
1400
29
1.1
1430
2.6
00
1100
1.7
10
.5
1800
20
1600 3.
1030 0.5
17
26-1 1115 0.4
26-2 1515
J.7
24-3 1900
27-1 1215 0.7
29-2 1545
29- 1730
4.8
750
0-1
0-2 12
11
10-3 1425
I.5
-4 1750
31-1 00
T.6
1-2 1410
1.8
18
1


1-1
-1 1
——
QVERAGE
IS.S 0.20 7.75 3.45 0.62 4.83 1.91 0.75 0.04 0.75
DENSITV
O.O o.00 0.O2 0.00 o.00 0.01 o.00 o.00 o.00 o.0o
Table 2
5
HABITAT E: GREA FFOTECTED BY SEAL ROCKS

2.
tidal



date time level
1500
2.e
11 0
38
1120
1.8

1400
.
.4
4 O
16
8
11
1130
o.
20

26
1715
5-2
29-1
120
e
5.
- 10
S8
24
- 1730
4.3
0-1
o
0
42
.
30-2 1245
1
4
1.4
0-3 1645
.
2
0-4 2000
8
5.
S1-1
710
31-2 1425
8 117
54
4
13 40
2.
18
O1-1
-
71
1 2
10

QVEERGE
7.61
oaa-
LEMSITY
o.o o.o . .00 .1 .0 . .0.0
Table 3
HABITAT C: BETWEEN BIRD AND SEAL ROCKS

tidal

S8

date time level
1145
2.1
0
1
.8
68
14
7.
1700
50
0
O.
1
1145
15
29-1
100
S1
1.3
O
+2 160
T.4
-00
4.4
0-2 1
1.
30-3 1710
26
-36
3.8
51-1 240
.
- 00
10
01-1
1.8
o1-2 10
5.2
1515
S 14 24
T.2
QVERAGE
2.86 15.1 1 7.8 15.1 5.0
DENSITY
5.00 o.0S 0.00 0.01 0.02 0.01 0.00
HAFITAT D: AREA PROTECTED BY BIED ROCKS
tidal


P

date time level
200
15
40
1430
12
1700
1600
5.6
9-1 1315
1.4
29-2 1840
3.5
-00
4.4
70-1 845 2.9
30-2 1230
1.4
0-3 1
0-4 20
4.3
1-1 950
O
7.2
18
1-2 1510
O
01-1 25
1.
5.
01-2 1225
0
14
15
C
QVERAGE
7.06 0.Oe 1.33 8.2 6 0.06 0.08 0.08 0.08
DENSITY
0.00 0.00 0.0 5.01 0.00 o.00 .0 o.o .o0
Tables
HABITAT E: CHONMEL FAST EIFD ROCKS

tidal

date time level
29-1 1.
4 15 104
1.5
29-2 1650
O
3.6

29-3 2015
4.3
10
30-1 00
O
2.8
45
38
30-2 1340
2
1.5
3O-3 1730
4.1
3
17
- 00
3.2
31-21570
39
34
2.7
18
17
45
01
1.5
O 2 45 0
O
o 00
18
AVERAGE
1 20.3 1.1 10.2 14.1 16.4 0.5
DENSITY
o.oo o.0 0.00 0.01 0.02 0.02 0.00
Table e
COMPOSITE DATA
FOR THE ENTIRE STUDY PERIOD
DENSITY (fish per
ten sq m):
striped pile
rainowre
black
o.09
average
O.19
O.17
O. 04
O.21
tracks
O.21
O.13
o.05
0.02
O.60
seal
O.OS
O.14
O.14
O.36
O.04
O.O5
O.30
o.29
O.11
O.02
between
bird
O.00
0.10
O. 11
o.o0
O.08
O.2
O.02
O.
O.2
channel
O.O1
ABUNDANCE (by fish):
striped
black
rainowreef
pile
65.
7.45
O.
tracks
10.60
12.80
2.65
seal
43.60
.00
34.2
70.42
79.75
8.57
22.00
J.45
1.20
between
12.89
O. 45
O.2
7.70
bird
7.36
27.
2.99
21.89
T.40
channel
20.10
total
0.00
00.00
00.00 100.00
.o0
Table 7
SSION STATISTICS
RE
Correlation between black surfperch under the tracks
and the height of theie
Regression Output:
42.090
Constant
Std Er ofYEst
12.41612
R Squared
O.389240
No. of Observations
Degrees of Freedom
X Coefficient(s) -7.25476
Std Err of Coef. 1.937537
Correlation between the number of reef surfperch
in the area protected by Seal Roc
and the height f the tide
Regression Output:
Constant
159.3666
Std Er of Y Est
SS.03032
R Squared
O.405103
18
No. of Observations
Degrees af Freedom
15
33.7242
X Caefficient(s)
Std Err of Coef.
10.21691
Jable 8
c
FIGURE LEGEND
Figure i - Hap of the protected nearshore zone off of Foint
Cabrille which constituted the study area. Habitat
boundaries are shewn.
Figure 2 - Graph of the average density of the five primary
Embictecid species found in the entire study area.
Density measured in fish per 10 square meters.
Figure 3 - Graph of the average density of each of the five
surfperch in each respective habitat. Density measured
in fish per 10 square meters.
Figure 4 - Fercent abundance measured solely by number of
fish observed in each habitat. Neither the size of the
habitats nor the differing total pepulations of the
species is taken inte acceunt.
S Correlation between the number of black zurfperch
Figure
cbserved under the railroad tracks and the height of
the tide. The line of regression was calculated and
drawn. Regression statistics presented in Table 8.
Figure 4 - Corrolation between the number of reef surfperch
observed in the area protected by Seal Rocks and the
height of the tide. The line of regression was
calculated and drawn. Regression statistics presented
in Table 8.
figure 7 - Statistically unsignificant correlation between
the number of reef surfperch observed in the channel
beyond Eird Rocks and the height of the tide.
Figure 8 - The density change of the surfperch or
Hepkins
Marine Life Reserve from 1979 to 1789. The 1979
densities are from Nichols (1979).
Figure 9 - The density change of the juvenile surfperch of
three speciez of zurfperch on Hepkins Marine Life
The 1977
Refuge from spring 1979 to spring 1989.
densities are from Nichals (1979).
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