Download The Relationship Between Habitat Structure

BULLETIN OF MARINE SCIENCE, 44(2): 681-697,1989
THE RELATIONSHIP BETWEEN HABIT AT STRUCTURE,
BODY SIZE AND DISTRIBUTION OF FISHES AT
A TEMPERATE ARTIFICIAL REEF
Todd W Anderson, Edward E. DeMartini and Dale A. Roberts
ABSTRACT
We examined the distributions and body sizes of fishes relative to prescribed microhabitat
strata at Pendleton Artificial Reef (PAR), San Diego County, California. Three intensive
surveys were conducted (November 1986-January 1987) to enumerate fishes by life stages
(juvenile, subadult, adult). Major microhabitats were crest and slope strata on modules (rock
substratum), and ecotone (sand-rock interface) and sand strata off modules. Four sand strata
were surveyed on transects that extended radially outward from module ecotones with each
stratum corresponding to a specified, increasing concentric distance from a module perimeter.
Size-frequency distributions of fishes were determined by estimating fish lengths in situ on
complementary surveys; length-weight regressions were used to calculate weighted mean
species-by-life stage body weights, from which biomass densities and body sizes were derived.
In general, numerical and biomass densities of fishes were higher in rock microhabitats than
over ecotone and sand regions. Mean individual fish body sizes (weights) were greater over
the ecotone and sand. Recruitment by young-of-year of the pomacentrid Chromis punctipinnis
to crest and slope strata, and the occurrence of the serranid Paralabrax nebulifer on the
ecotone and sand, greatly affected overall densities. In addition, life-stage differences among
strata occurred for eight of nine select species examined. Given that recruitment by youngof-year fishes can be extremely variable, numerical density patterns among strata at PAR
may change over time, while biomass densities should remain relatively unaffected. The
interrelationships of numerical density, biomass density, and body size suggest that juveniles
and small-bodied fishes have more specialized habitat requirements (greater need for shelter)
than do large-bodied fishes or older life stages.
Whether physical or biological, the amount and type of habitat structure often
influence the distribution and abundance of fishes (Keast et al., 1978; Orth and
Heck, 1980; Ogden and Ebersole, 1981; Schlosser, 1982; 1987; Stoner, 1982;
1983; Werner et al., 1983a; 1983b; Holbrook and Schmitt, 1984; Ebeling and
Laur, 1985; Helvey and Smith, 1985; Choat and Ayling, 1987; Gotceitas and
Colgan, 1987). These distributions are usually in response to food availability or
preference, predation, or the combined influence ofthese factors. Components of
the environment such as relief, spatial heterogeneity, structural density, and substratum characteristics contribute to varying degrees of structural complexity
(Quast, 1968a; Feder et al., 1974; Luckhurst and Luckhurst, 1978; Ebeling et al.,
1980a; 1980b; Savino and Stein, 1982).
Quantitative characterizations of fishes in subtidal natural and artificial habitats
are usually expressed as numerical density or relative abundance (Bray and Ebeling, 1975; Ebeling and Bray, 1976; Jessee et al., 1985). More recently, biomass
densities (Larson and DeMartini, 1984; Laufle and Pauley, 1985; Bodkin, 1986)
have been estimated which may be more appropriate in comparisons of fishes
within and among areas when disparities in fish size or life stages exist. Moreover,
numerical or biomass abundance (total numbers or weight over a delimited area),
has been neglected due to the difficulty in quantifying the area studied (DeMartini
et al., 1989), especially if delineations of microhabitats within a heterogeneous
area are required.
Our objective was to estimate and compare the numerical density, biomass
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BULLETIN OF MARINE SCIENCE, VOL. 44, NO.2, 1989
density, and body size of fishes within major microhabitats at an artificial rock
reef placed on sand bottom. While we fully expected that numerical density would
decrease over contiguous strata beginning at reef-module apices and extending
outward over sand, we also hypothesized that larger fish would occur in areas
with less apparent shelter (i.e., sand) and that this might result in similar biomass
densities on sand and rock strata.
STUDY AREA
Pendleton Artificial Reef (PAR) was constructed in 1980 by the California Department of Fish and
Game to determine the mitigative potential of such reefs for offsetting possible habitat losses due to
the effects of coastal power plants (Grant et aI., 1982; Grove, 1982), and has been one of the most
studied artificial reefs to date (Ambrose, 1986). PAR covers a total sand-rock areal extent of appro ximately 3 ha and consists of quarry rock in an array of eight rock piles (modules) positioned on a
sand bottom at a depth of 13 m off northern San Diego County, California (Carter et a!., 1985, figs.
1-2). Major microhabitats at PAR (see Methods), with areal extents and relative proportions of total
area, include the crest (2,401 m2; 7%), slope (6,623 m2; 19%), ecotone (3,654 m'; 11%), and sand
(21,592 m2; 63%). Physical and biological characteristics of PAR have been thoroughly examined
(Carter et aI., 1985; Jessee et aI., 1985; also see DeMartini et a!., 1989 for a summary of general
physical characteristics).
METHODS
Sampling Design. - We sampled seven defined strata per module during each of three surveys (November 1986-January 1987). All eight modules were surveyed to determine the mean density, distribution, and body size of fishes. Strata included the crest and slope on rock substratum, an ecotone
stratum (0-3 m zone outward from the sand-rock interface) on the module perimeter, and four sand
strata corresponding to concentric bands at increasing distances from the module perimeter: 3-8 m,
8-13 m, 13-23 m, and 23-33 m (Fig. I).
On each survey, fishes on the crest, slope, and ecotone strata of each module were surveyed with
one 3-m wide by 1.5-m high belt transect. An observer swam along the major axis and apex of the
module (crest), the midpoint between the crest and module perimeter (slope), and the distance along
the sand-rock interface of the module perimeter (ecotone). A complementary description of the methodology with additional information on sampling protocols is provided by DeMartini et a!. (1989).
Fishes on sand strata were surveyed by swimming a 30-m or 5-m transect of the same aforementioned
dimensions at a fixed compass bearing perpendicular to, and bcginning 3 m from, the module perimeter.
We sampled one transect in each of the four quadrants of a module. Stratum boundaries corresponded
to 5 m, 10 m, 20 m, and 30 m from the 0-3 m ecotone zone. Length of transects varied with extent
of available sand habitat; due to the configuration and close proximity of many modules, only 5-m
transects could be used without overlapping sand regions sampled off adjacent modules. A total 32
sand-stratum transects was completed per survey, 22 of which were 30 m in length.
Fish encountered on transects were enumerated by species and by life stage (juvenile, subadult,
adult) based on cm total length (Table I; DeMartini, 1987). In addition, three complementary fishlength surveys to determine total body length-by-life stage size distributions were conducted by observers on 20-min haphazard swims of each module; distributions were applied to length-weight
regressions in estimating weighted mean weights for each species and life stage, from which biomass
density and body size were derived.
Three separate surveys of juveniles only were done during the study to estimate proportions of
young-of-year (fish < I yr old) and older juvenile subgroups based on size (cm total length). Crest and
ecotone strata were sampled with I-m wide by I-m high (ecotone) or 2-m high (crest) belt transects;
juveniles were scored by species and subgroup.
Analyses. - Mean numerical (no. fish· 1,000 m-3) and biomass (g. I,000 m-3) densities were calculated
for all species observed at PAR (Table I, biomass expressed as kg. 1,000 m-3). Species were selected
for further analyses based on anyone of three criteria: (I) high relative numerical or biomass density,
(2) common occurrence, and (3) economic importance. The density of total resident fishes (species
that consistently occurred at PAR) was estimated for all taxa with the exclusion of transient fishes,
the pelagic species Sarda chiliensis and Trachurus symmetricus. Body size (g.individual-I) by species
and stratum was calculated by applying species-by-life stage weighted mean weights to all individuals
tallied on transects.
We used a balanced two-factor, fixed-effects model analysis of variance (Sokal and Rohlf, 1969),
with surveys as temporal replicates and stratum and life stage as main effects to compare species
ANDERSON ET AL.: ARTIFICIAL
REEF FISH DISTRIBUTION
AND BODY SIZE
683
PENDLETON
ARTIFICIAL
REEF
30M
30M
Figure I. Schematic representation of top and side views of Module 2, depicting crest, slope, ecotone,
and sand strata sampled at Pendleton Artificial Reef. Length of sand transects (30 m or 5 m) for each
module was dependent upon proximity of adjacent modules.
density and life-stage differences among strata. Spatial replicates (modules) were not used because we
had reason to believe that fish move between modules. Further, we believed that fish had the opportunity or did become redistributed among strata on modules between surveys so that surveys were
therefore independent. Fishes such as Embiotocajacksoni, Halichoeres semicinctus, Paralabrax clathratus. and Semicossyphus pulcher exhibit movement from rock substrata out over sand (Hobson and
Chess, 1986) and would therefore be likely to move among strata. Module was used as a "blocking
variable"; i.e., it was used as a factor in the model to exclude possible module differences from the
error term. Inclusion of module variation in the error term would have increased the probability of
accepting a false null hypothesis (Type II error). We then applied the Student-Newman-Keuls (SNK)
multiple range test (Winer, 1971) to identify differences. Numerical and biomass densities were transformed using log,o(x + I) to more closely approximate a normal distribution and equalize variances
prior to statistical analysis.
We used the Spearman rank correlation coefficient (Siegel, 1956) as a conservative test of whether
the mean body size of a species differed among strata. Analysis of variance was not used to evaluate
body size due to (I) high power from the large number of replicates (where replicate = individual fish
observed on a stratum over the study period) and (2) reduced variances from applying a constant
species-by-life stage weighted mean weight to fish of the same life stage. These factors contribute to
a high probability of detecting significant differences.
RESULTS
A general pattern of decreasing numerical and biomass density occurred from
crest to sand strata for all but two of the nine select species examined (Table 2).
684
BULLETIN OF MARINE SCIENCE, VOL. 44, NO.2,
1989
Table 1. Noncryptic fishes observed on transects at Pendleton Artificial Reef, with size classes (cm
total length) and life stages (1 = juvenile, S = subadult, A = adult) noted. Select species used in analyses
are denoted by an asterisk (*); t = transient fishes; = length of single individual recorded and biomass
calculated from length-weight regression
*
Life stage
Family/Species
Scorpaenidae
Scorpaena guttata
Sebastes serranoides
Hexagrammidae
Oxylebius pictus
Serranidae
Paralabrax clathratus*
Paralabrax nebulifer*
Carangidae
Trachurus symmetricust
Haemulidae
Anisotremus davidsonii
Sciaenidae
Cheilotrema saturnum
Kyphosidae
Girella nigricans
Medialuna californiensis*
Embiotocidae
Embiotoca jacksoni*
Rhacochilus toxotes
Rhacochilus vacca
Pomacentridae
Chromis punctipinnis*
Hypsypops rubicundus*
Labridae
Halichoeres semicinctus*
Oxyjulis californica*
Semicossyphus pulcher*
Scombridae
Sarda chiliensist
Bothidae
Paralichthys calif amicus
Balistidae
Balistes polylepis
Common name
S
A
California scorpionfish
olive rockfish
<20
<20
20-30
20--30
>30
>30
painted greenling
<IS
15-17.5
>17.5
kelp bass
barred sand bass
<22.5
<22.5
jack mackerel
<IS
sargo
<12.5
12.5-22.5
>22.5
black croaker
< 17.5
17.5-25
>25
opaleye
halfmoon
<17.5
<12.5
17.5-25
12.5-20
>25
>20
black perch
rubberlip seaperch
pile perch
<10
<IS
<12.5
10--17.5
15-25
12.5-22.5
>17.5
>25
>22.5
blacksmith
garibaldi
<10
<12.5
10--15
12.5-25
>15
>25
rock wrasse
senorita
California sheephead
<12.5
<10
<25
12.5-20
10-15
25-35
>20
> 15
>35
Pacific bonito
<57.5
57.5-62.5
>62.5
California halibut
<22.5
22.5-45
>45
finescale triggerfish
22.5-30
22.5-30
>30
>30
15-25
>25
-*
Overall density relationships were greatly affected by two species (Fig. 2). Chromis
punctipinnis constituted over three-quarters of total numerical density on rock
strata. Paralabrax nebulifer, although relatively low in numerical density, had
highest biomass densities over sand, accounting for almost 30% of total biomass
density over outlying sand strata. The labrids Semicossyphus pulcher and Halichoeres semicinctus contributed substantially to both numerical and biomass density on the crest, slope, and ecotone. Embiotoca jacksoni and P. clathratus also
followed the trend of decreasing density with distance from the crest, as did
Medialuna californiensis and Hypsypops rubicundus; the latter two species had
truncated distributions in that densities were trivial on the ecotone and over sand.
Density differences among strata were strongly influenced by the distribution
of life stages within species (Fig. 3), as evidenced by numerous significant interactions (Table 3). Chromis punctipinnis, E. jacksoni, H. semicinctus, H. rubicundus, M. californiensis, P. clathratus, S. pulcher, and total resident fishes had
685
ANDERSON ET AL.: ARTIFICIAL REEF FISH DISTRIBUTION AND BODY SIZE
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SLOPE ECOTONE
STRATUM /
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DISTANCE FROM MODULE (M)
Figure 2. Estimated mean numerical density (no -1,000 m -3), biomass density (kg· 1,000 m-3), and
mean body size (g/individual) of Chromis punctipinnis, Paralabrax nebulifer. and total resident fishes
across microhabitat strata at Pendleton Artificial Reef. Standard errors are averaged over surveys (N
= 3). Means and standard errors for body size are based on number of individuals observed within
a stratum over the study period (Table 5).
686
BULLETIN OF MARINE SCIENCE, VOL. 44, NO.2, 1989
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BULLETIN OF MARINE SCIENCE, VOL. 44, NO.2, 1989
TOTAL FISHES
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Figure 3. Estimated mean numerical (no· 1,000 m-J) and biomass (kg· I ,000 m-J) densities ofChromis
punctipinnis, Paralabrax nebulifer, and total resident fishes by life stage (juvenile, subadult, adult)
across microhabitat strata at Pendleton Artificial Reef. Standard errors are averaged over surveys (N
~ 3).
ANDERSON ET AL.: ARTIFICIAL
REEF FISH DISTRIBUTION
691
AND BODY SIZE
Table 4. Percentages of young- of-year (YOY) and older juveniles (OJ) of select species from estimated
numerical densities on juvenile surveys, and percentage juveniles from estimated numerical densities
on surveys of all life stages (juvenile, subadult, adult). t All juveniles classified as young-of-year by
definition
.
Juveniles
Species
Chromis punctipinnis
E mbiotoca jacksoni
Halichoeres semicinctus
Hypsypops rubicundus
Medialuna californiensis
Oxyjulis californica
Paralabrax clathratus
Paralabrax nebulifer
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Total Fishes
All Stages
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significantly higher densities of juveniles or subadults on the crest than other
stratum-life stage combinations. In contrast, Oxyjulis californica, although not
abundant at PAR, had highest juvenile densities on the slope and ecotone because
of the presence of young-of-year (Table 4) in these specific microhabitats. The
absence or rarity of young-of-year recruits or older juveniles was typical for H.
semicinctus, H. rubicundus, and M. californiensis. An opposite density pattern
occurred for P. nebulifer which showed no stratum-by-life stage interaction and
had highest numerical and biomass densities over sand strata and the ecotone.
We found interaction effects in numerical density for three species (M. californiensis, O. californica, and P. clathratus) which had insignificant interaction effects
in biomass density (Table 3). Similarly, significant module differences were found
for numerical but not biomass densities of O. californica. Numerical and biomass
densities also differed among modules for C. punctipinnis, P. clathratus, and total
resident fishes. Module contrasts, however, showed great overlap, with only one
or at most two modules not part of a common grouping of homogeneous means
(Table 3).
Body size appeared to increase from crest through sand strata (Fig. 2), although
significant stratum differences were found only for C. punctipinnis, S. pulcher,
and total resident fishes (Table 5). Few or no fish of several species were observed
in outlying sand strata.
DISCUSSION
Species Distributions. - The fish species assemblage that we observed at PAR in
fall 1986 was generally representative of other southern California artificial reefs
(Carlisle et aI., 1964; Turner et aI., 1969; Ambrose, 1987) and essentially the same
as that found by Jessee et aI. (1985) at PAR in 1981-1983. The occurrence of C.
punctipinnis in aggregations above modules and on the crest stratum apparently
reflects its habit of orienting to currents and feeding on zooplankton which are
swept across reefs (Bray, 1981). The numerical dominance of C. punctipinnis at
PAR, particularly by young-of-year, is evidence of numerous interstices and holes
that afford them shelter at night (Bray, 1981). In contrast to larger conspecifics,
juveniles do not usually venture more than a few meters from reef-tops (Hobson
and Chess, 1976; Jessee et aI., 1985). This may be a consequence of the increased
692
BULLETIN OF MARINE SCIENCE, VOL. 44, NO.2, 1989
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ANDERSON ET AL.: ARTIFICIAL
REEF FISH DISTRIBUTION
AND BODY SIZE
693
risk of predation with distance from shelter and the greater vulnerability of smaller
fish.
The limited distributions of H. rubicundus and M. californiensis on rock strata,
particularly module crests (Jessee et a1., 1985), is probably due to their affinity
for turf and foliose algae with the consumption of associated invertebrates, or the
cultivation of turf algae (H. rubicundus) during breeding (Limbaugh, 1955; Quast,
1968c; Clarke, 1970; Feder et a1., 1974). These algae have been more abundant
on the crest than on other module areas (Carter et a1., 1985).
The greater densities of older juveniles of the piscivore P. clathratus (Limbaugh,
1955; Quast, 1968b; Feder et a1., 1974) on crests may be due to the number of
prey present (e.g., young-of-year C. punctipinnis), or simply the result of an attraction to algal or invertebrate assemblages. Paralabrax clathratus does feed on
benthic invertebrates (Hobson and Chess, 1976; 1986; Love and Ebeling, 1978),
which these algae may contain. The rarity of young-of-year P. clathratus is apparently related to the lack of giant kelp (Macrocyst is pyrifera) as suitable habitat
(Larson and DeMartini, 1984; M. Carr, pers. comm.). The presence of subadult
and adult P. clathratus over sand is not surprising since it is known to leave kelp
forests and forage over sand (Ebeling et a1., 1980a; Hobson and Chess, 1986).
Both E. jacksoni and S. pulcher had significantly higher densities on the crest.
Jessee et a1. (1985) found that these species preferred the bottom of modules at
PAR and speculated that (1) juveniles of E. jacksoni, because of high densities
on the bottom, utilize this area for predator avoidance by blending in with cobbles
and boulders, and (2) S. pulcher may shelter at night and forage during the day
in holes near the bottom, and also feed over sand areas near the bases of reefs.
We found the numerical density of subadult E. jacksoni to be significantly greater
on the crest than the slope and ecotone, and juvenile densities were greater on
the crest and slope than the ecotone. Ebeling and Laur (1985) determined that
the subcanopy- and understory-forming laminarian algae Pterygophora californica
and Laminariafarlowii provided a refuge for juvenile E. jacksoni. The occurrence
of juveniles is highly correlated with foliose algae, whereas adults favor algal turf
(Holbrook and Schmitt, 1984). Schmitt and Holbrook (1985) observed that youngof-year preference for foliose algal patches depended most on food quality and
secondarily on physical structure, even under high risk from predation. Given
that subcanopy or understory kelp was absent at PAR in fall 1986, we would
expect that the numerical densities of E. jacksoni would be greatest on module
crests where higher light levels are more conducive to the growth of turf or foliose
algae. The greater densities of S. pulcher on crests may be due to the increase in
available prey from the recent establishment at PAR of large-scale patches of
small mussels (Mytilus) (author's obs.; also see Limbaugh, 1955; Quast, 1968c;
Feder et a1., 1974; Cowen, 1983). Notwithstanding, E. jacksoni and S. pulcher
are known to forage over sand (Ebeling et a1., 1980a; Hobson and Chess, 1986).
The low numerical density of O. californica suggeststhe lack of suitable vegetated habitat (Limbaugh, 1955; Quast, 1968c; Feder et a1., 1974; Bray and Ebeling,
1975; Bernstein and Jung, 1979). The occurrence of young-of-year on the slope
and ecotone may be due to predator avoidance. Drift algae (e.g., Cystoseira osmundacea and M. pyrifera) present along the bases of modules might provide
refuge and food in the form of invertebrate prey. In addition, the visual acuity of
predators may be reduced on the ecotone from contrasting light (sand) and dark
(rock) patterns. Since O. californica partially buries itself in sand at night (Feder
et a1., 1974), close proximity to this area may be important for the highly vulnerable young-of-year.
Two other fishes, H. semicinctus and P. nebulifer, also recruit as young-of-year
694
BULLETIN OF MARINE SCIENCE, VOL. 44, NO.2, 1989
to the sand-rock interface (DeMartini, 1985), but recruitment apparently was
negligible in 1985 and 1986 (author's obs.). The lack of older juveniles of H.
semicinctus in ]986 underscores the poor 1985 recruitment. The relatively higher
densities of H. semicinctus on crests and slopes probably reflect food availability
or preference, although individuals do pick prey over sand (Ebeling et al., 1980a;
Hobson and Chess, ]986). The almost exclusive occurrence of P. nebulifer on
sand and the ecotone is consistent with their known habitat (Limbaugh, 1955;
Quast, 1968c; Feder et al., ]974). The importance in the diet ofbrachyuran crabs,
pe]ycypods, and to a lesser extent mysids (Roberts et aL, ]984), is indicative of
its distribution.
Density and Body Size Interrelationships. - The decrease in numerical density
from reef crests outward, although expected, was greatly affected by the numerical
dominance and distribution of C. punctipinnis. Contrary to our hypothesis, biomass density was also greater over rock strata but was not affected by the relatively
small contribution of C. punctipinnis in terms of weight. Still, the biomass provided by larger but numerically fewer fishes (e.g., H. semicinctus, S. pulcher) was
enough to support high densities on module crests. Numerica] and biomass densities on sand were due to primarily solitary P. nebulifercombined with the patchy
and highly variable distributions of schooling fishes (e.g., Anisotremus davidsonii
(sargo), C. punctipinnis) that presumably travel between modules. We speculate
that since recruitment by young-of-year fishes can be highly variable, numerical
but not biomass density patterns may vary among strata over time.
The density differences seen between modules were slight, as indicated by the
great overlap in means (Table 3). These differences are not readily explained other
than by the chance distribution of fishes at the time of sampling, except perhaps
for C. punctipinnis. Chromis had highest densities on modules ]-4, some of which
are the farthest offshore of the eight modules, and therefore the most likely to be
bathed by currents, particularly those from the northwest. If so, these modules
might be preferred by p]anktivores. Although the modules at PAR were originally
constructed using different proportions of rocks of varying sizes (Carter et aI.,
1985), seemingly equivalent stands ofbush-]ike colonia] invertebrates (primarily
Muricea spp.) on all PAR modules in 1986 probably diluted differences in fish
densities due to the physical characteristics of the modules themselves. We note
that the density patterns observed on PAR may not be similar to those found on
other temperate reefs because of gross differences in configuration (e.g., high-relief
rock vs. low-relief rock with few interstices).
As predicted, body size increased with distance from module crests, but not
enough to compensate for fewer fish and a concomitant decrease in biomass
density. However, a posteriori tests for biomass density differences had fewer
significant stratum-by-]ife stage interactions than for numerical density. We attribute this to the averaging effects of larger numbers but smaller fish on rocks,
with fewer individuals of greater size off modules. This would imply that if the
size distributions of fishes present on or between reefs were markedly dissimilar,
differences in numerical density, although significant, might be trivia] relative to
biomass density and different conclusions would be drawn. Alternately, distribution patterns of very small but potentially numerous fishes such as young-ofyear recruits might be masked by examining only biomass density (DeMartini et
al., 1989).
Clearly, there is reason to examine both numerical and biomass density in
characterizations of fish assemblages, especially when fish size differences exist.
The differences between life stages of species or small- and large-bodied fishes
ANDERSON ET AL.: ARTIFICIAL REEF FISH DISTRIBUTION AND BODY SIZE
695
among strata are apparently related to their respective habitat requirements. We
acknowledge that the results of this short-term study do not allow extrapolation
of seasonal or annual distribution patterns at PAR, nor do they imply that these
patterns are necessarily similar spatially at other reefs. Fish size distributions,
physical and biological substratum characteristics, and habitat requirements of
the particular fish species should explain the distribution patterns observed, however.
Size-related differences in habitat utilization for fishes (Mittelbach, 1981; Werner et aI., 1983a; 1983b; Holbrook and Schmitt, 1984; see Werner and Gilliam,
1984 for review; Choat and Ayling, 1987; Schlosser, 1987) have recently received
much attention. The determination of relevant factors that govern these differences
would greatly advance our understanding of species distributions.
ACKNOWLEDGMENTS
We express our appreciation to R. Fountain and F. Koehrn for diving assistance, J. Callahan and
A. Carpenter for statistical advice, V. Breda and R. Smith for graphics assistance, W. Watson for
drafting Figure I, J. Azar for typing the tables, and M. Carr for reviewing the manuscript. This paper
is a result of research funded by the Marine Review Committee (MRC) of the California Coastal
Commission. The senior author thanks the MRC for providing travel funds. The MRC does not
necessarily accept the results, findings, or conclusions stated herein.
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ETAL.:ARTIFICIAL
REEFFISHDISTRIBUTION
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DATEACCEPTED: May 11, 1988.
ADDRESSES: (T. W.A.) Marine Science Institute. University of California at Santa Barbara. California
93106; (E.E.D. and D.A.R.) Marine Review Committee Research Center, 531 Encinitas Boulevard.
Suite 105. Encinitas, California 92024; PRESENT
ADDRESSES:
(T.N.A.) Department of Biological Sciences
and Marine Science Institute, University of California, Santa Barbara. California 93106; (E.E.D.)
MEC Analytical Systems. Inc., 2433 Impala Drive, Carlsbad. California 92009; (D.A.R.) SAIC, 4224
Campus Point Court, San Diego. California 92121.