Transactions of the American Fisheries Society 130:478–488, 2001
q Copyright by the American Fisheries Society 2001
Density-Dependent Overwinter Survival and Growth of Red
Shiners from a Southwestern River
WILLIAM J. MATTHEWS
Sam Noble Oklahoma Museum of Natural History,
University of Oklahoma Biological Station, and Department of Zoology,
University of Oklahoma, Norman, Oklahoma 73019, USA
KEITH B. GIDO
Department of Zoology and University of Oklahoma Biological Station,
University of Oklahoma, Norman, Oklahoma 73019, USA
EDIE MARSH-MATTHEWS
Sam Noble Oklahoma Museum of Natural History and Department of Zoology,
University of Oklahoma, Norman, Oklahoma 73019, USA
Abstract.—The red shiner Cyprinella lutrensis is the most widespread and abundant minnow
(Cyprinidae family) in central and southwestern North America, occurring at very high local
densities in streams from northern Mexico to Nebraska and Iowa. The streams in which red shiners
occur are typically harsh, unpredictable environments with temperature extremes and episodes of
low oxygen, floods, and drought. In outdoor experimental streams, red shiners stocked at densities
typical of natural streams showed moderate density effects on overwinter survival and strong
effects on growth from October to May. At lower densities a higher percentage (.70% on average)
of individuals survived winter, and most grew to adult size the next spring. At higher densities
survival and average growth were lower, and the distribution of final body size was highly skewed,
with a few individuals reaching sexual maturity and most remaining at the juvenile stage. The
apparent growth of the cohort in the Washita River, Oklahoma, from which experimental fish were
taken, was similar to that of red shiners at high densities in the experimental streams, suggesting
that red shiner population parameters are density dependent in the wild despite the strong potential
for the influence of abiotic factors in their typical habitats.
Density effects on life history parameters (natality, growth, and mortality) are known for many
taxa (Wilbur 1977, 1997; Morin 1986; Petranka
and Sih 1986; Semlitsch 1987a, 1987b; Petranka
1989; Murdoch 1994; Cappuccino and Harrison
1996; Rodenhouse et al. 1997). Harrison and Cappuccino (1995) reported density-dependent effects
on vital population parameters in 78% of 60 density manipulation experiments since 1970. By affecting growth or survival of individuals (Murdoch
1994; Rodenhouse et al. 1997; Wilbur 1997; Jenkins et al. 1999), density has potential consequences for population dynamics (Tamarin 1978) or life
history evolution (Saski and de Jong 1999).
For fish, density can affect growth, reproductive
output, recruitment, the size structure of populations, variance in body size within a cohort, and
the condition of individuals (Brett 1979; Smith et
al. 1978; Schlosser 1987, 1998; Wootton 1990;
Wedemeyer 1997). Field and experimental studies
* Corresponding author: wmatthews@ou.edu
Received January 31, 2000; accepted January 14, 2001
(Gilliam et al. 1989; Crisp 1993; Michaletz 1997;
Dunson and Dunson 1999; Jenkins et al. 1999;
Schmitt and Holbrook 1999) and modeling (e.g.,
Dong and DeAngelis 1998; McCann 1998) show
the importance of density-dependent effects on
population parameters of fishes, but the specific
effects of density or threshold levels at which vital
rates become density dependent vary within and
among species. For example, Crisp (1993) found
that the survival of brown trout was independent
of density up to the early parr stage but density
dependent for juveniles. Mesocosm experiments
showed that density affected the survival of the
larvae of gizzard shad Dorosoma cepedianum but
not those of bluegills Lepomis macrochirus (Welker et al. 1994). Although growth is inversely related to density for many fish species (Boisclair
and Leggett 1989), Baltz et al. (1998) found that
the growth of spotted seatrout Cynoscion nebulosus
and red drum Sciaenops ocellatus was not a function of density.
Density-dependent effects on the life history parameters of aquatic organisms have been shown
478
479
RED SHINER DENSITY DEPENDENCE
most often in relatively closed systems, such as
with fish or tadpoles in ponds or lakes and reef
fish limited to patchy habitats (Schmitt and Holbrook 1999). Less is known about density effects
for species in the more ‘‘open’’ or frequently disturbed habitats of streams (e.g., Jenkins et al.
1999). However, Starrett (1951) speculated that
floods that reduced the populations of minnows in
river mainstreams might be beneficial, allowing
‘‘relief from crowding’’ and facilitating growth of
new-generation individuals, and Schlosser’s
(1987) model of stream fish population dynamics
incorporated density-dependent growth of small
individuals. Recently, Schlosser (1998) showed
that the growth and overwinter mortality of creek
chubs Semotilus atromaculatus in a Minnesota
stream were density dependent.
Red shiners Cyprinella lutrensis are widespread
and locally dense in streams of the central and
southwestern United States (Matthews 1980).
Across more than 60 stream sites in the southern
Great Plains, more than 50% of all fishes collected
were red shiners (Marsh-Matthews and Matthews
2000). Red shiners thrive in harsh environments
(Hefley 1937; Cross and Collins 1975) with unpredictable flow and fluctuations in temperature
and oxygen concentration (Matthews 1987, 1988,
1998; Matthews and Zimmerman 1990). Drought
(Matthews 1987, 1998) and flood (Starrett 1951;
Harvey 1987) can reduce local fish populations in
such streams, and winter can be a period of high
mortality for fishes (Matthews 1998). Many
streams where red shiners are abundant have
strong potential for abiotic, density-independent
control of population size at some time in the annual cycle (e.g., Schlosser 1987; Jennings and Philipp 1994), which may introduce stochastic variability in population densities as winter begins. For
red shiners, autumn populations commonly are
dominated by juveniles, with relatively few adults
(Matthews and Hill 1979). The dense prewinter
populations of small red shiners that are common
in Oklahoma streams in some years (Matthews
1977; Matthews and Hill 1979, 1980) suggest that
density variation in winter may have important
consequences for growth, survival, and other population parameters in this species.
We tested the effects of density on young red
shiners in large, outdoor experimental stream units
and compared these results with the apparent
growth in the natural population from which they
were collected (the Washita River, Oklahoma). In
a 7-month experiment from October 1998 to May
1999 we tested density effects on overwinter sur-
vival, mean individual growth, and variance in final body size among individuals, with densities
ranging from very low ones to those approximating the higher densities found in the field.
Methods
The experiment was conducted in outdoor artificial streams at the University of Oklahoma Biological Station, Marshall County, Oklahoma
(Gido et al. 1999). This system, which has modular
pool and riffle units connected in various configurations, has been used in research on at least 12
species of minnows (Cyprinidae), topminnows
(Fundulidae), sunfish (Centrarchidae), and darters
(Percidae) (e.g., Gido et al. 1999; Gido and Matthews 2001). All species in these streams (including red shiners) have survived well and exhibited
normal behavior, and most have reproduced (Gido
et al. 1999; F. P. Gelwick and Matthews, unpublished data).
Each individual experimental unit consisted of
one pool 183 cm in diameter and 45 cm deep in
the middle, with the bottom contoured to mimic
the naturally sloping bottoms of small pools and
a connected riffle 123 cm long 3 45 cm wide 3
15 cm deep (see diagram in Gido and Matthews
2001). Moderate flow through the riffle and pool
was provided by a 1/8-horsepower (93-W) pump
in a screened footbox that returned water to the
head of the riffle, where vigorous splashing on
stones provided aeration. Substrate was a natural
mixture of gravel, sand, and silt from a nearby
stream. Streams were outdoors and open to natural
weather conditions and flying insects. Our experimental stream units were comparable in size to
some of the stream pools and backwaters in which
red shiners typically concentrate in autumn or winter (Matthews and Hill 1979).
The streams were drained (from an earlier experiment), cleaned with a high-pressure hose, and
allowed to dry with the substrate exposed to full
sun for a week, then filled in October 1998. Equal
aliquots of algae (and any attached invertebrates)
that were scraped or brushed from stones in nearby
Brier Creek (mostly Spirogyra and Rhizoclonium
spp.; Power and Stewart 1987; Power et al. 1985;
Gelwick and Matthews 1992) were added to each
unit, and a 10-mL supplement of liquid fertilizer
(20:3:3, N:P:K) was added to promote algal
growth following Stewart (1987) and Vaughn et
al. (1993). Streams were left nonflowing until 26
October to enhance initial algal attachment and
growth, then pumps were turned on.
On 29 October, red shiners were collected by
480
MATTHEWS ET AL.
seining in the Washita River at State Highway 53,
Carter County, Oklahoma. Haphazardly selected
individuals representing sizes typical of the population were preserved in a 10% solution of formalin for determination of size, and the others
were transported to the University of Oklahoma
Biological Station in insulated containers. No mortality occurred in transporting or stocking fish in
the experimental units. Water temperature in the
river was 248C at the time of collection; it ranged
from 24.88C to 25.48C in the artificial streams on
the day the red shiners were introduced.
The experimental design described below was
used to simultaneously test two completely separate hypotheses: (1) that red shiners would affect
benthic primary productivity in the experimental
streams (Gido and Matthews 2001) and (2) that
red shiners would show density-dependent effects
on survival and growth (as reported here). The
experimental units were stocked by drawing fish
haphazardly from the common pool of individuals
seined from the Washita River to create (for this
experiment) densities of 7, 14, 21, 28, 42, 56, or
70 red shiners per stream unit, with two replicates
at each density ranging from 2.7 to 26.6 fish/m2.
This design facilitated the detection of either linear
or threshold responses of the species across densities (Goldberg and Scheiner 1993).
The experimental densities were chosen to represent red shiner densities in the field, which can
be very high. Gido and Propst (1999) found more
than 50 individuals/m2 for a population in New
Mexico. In small pools in the South Canadian River, Oklahoma, Matthews (1977) found more than
1,000 red shiners in some seine hauls comprising
10 m2 (i.e., . 100/m2), with an average across
three seasons of one year of 12.9/m2 in randomized
sampling. In obtaining fish for this experiment, we
found large numbers of small individuals concentrated near shore, approximating the higher densities observed by Matthews (1977) in the South
Canadian River. In February 2000, at another location further upstream, Matthews collected more
than 800 small red shiners in a dense shoal occupying only a few square meters of stream. We
made no attempt at precise density measurements,
but our observations consistently show high local
densities of red shiners in the Washita River in
autumn and winter.
Individuals were matched as nearly as possible
to a visually estimated average size for the wild
population. Altogether, the 262 individuals preserved at the Washita River collecting site in October 1998 had a mean standard length (SL) of
21.3 mm, with a standard deviation of 3.0 mm. To
minimize handling stress, we did not measure the
individuals placed in the experimental units but
assumed that the sizes for the subsample preserved
in the field adequately represented the initial sizes
of fish in the experimental units. We further assumed that our haphazard assignment of individuals among the units resulted in no significant differences among units in initial size or energy reserves, both of which can have important effects
on the survival and growth of young fish (Keast
and Eadie 1985). Individuals not used in initial
stocking were retained in holding units of similar
size for use as replacements (see below).
The food available to fish in the experimental
streams included the invertebrates initially stocked
along with algae from Brier Creek, larvae subsequently introduced by oviposition (mostly dipterans, with some mayflies and odonates), winged
adults alighting on or falling onto the surface of
the pools, and zooplankton that developed in the
pools. There was no supplemental feeding. In all
of our studies in these streams since 1992, there
has been substantial colonization by chironomids
or other dipterans as well as the development of
large standing crops of mayflies, odonates, and
snails (from initial slurry). On 3 December 1998,
a single (to minimize disturbance to the system)
Hess sample (0.33 m in diameter with 500-micron
mesh, equaling 0.087 m2) was taken from each
unit. At the end of the experiment on 20 May 1999,
three subsamples (total, 243 cm2) were taken with
a 102-mm (interior diameter) polyvinyl chloride
corer (Palmer and Strayer 1996) in each pool, combined into a single sample, filtered through 500micron mesh, and enumerated. Larval dipterans
dominated the invertebrate samples in December
(82% of total individuals) and in May (98% of
total individuals). Small populations of larval
Ephemeroptera, Odonata, Plecoptera, Coleoptera,
Gastropoda, and other aquatic invertebrates were
also present. The density of the dipterans ranged
from approximately 300 to 2,800/m2 in December
and from approximately 400 to 24,000/m2 in May,
with no relationship between the density of fish
and total dipterans in either sampling period (P 5
0.49 and 0.47 in December and May, respectively).
From 29 October to 4 December, fish were untouched in the experimental streams, and no mortality was observed. On 4 December, 7 individuals
were removed for an interim growth assessment
from units with an initial density of 70 individuals
and 5 individuals were removed from units with
an initial density of 14 individuals. These were
481
RED SHINER DENSITY DEPENDENCE
replaced with individuals of nearly identical size
from the holding tanks. After this intrusion into
the experiment, fish were left untouched until 19
May 1999, when all fish were harvested by seining,
photographed, and preserved for measurement of
length. In May 1999, we also obtained another
sample of red shiners by seining at the original
Washita River site for determination of length frequency in the field population.
Preserved specimens were measured to the nearest 1 mm SL. The mean standard length and skewness (Sokal and Rohlf 1995) of the size-frequency
distribution were calculated for the surviving fish
in each experimental unit. Skewness is an indicator
of the degree of growth depensation (Wohlfarth
1977; Shelton et al. 1979; Keast and Eadie 1985)
within a treatment, that is, growth to a large size
by a few individuals together with limited growth
by most individuals.
The effects of density on mean size, skewness,
and condition were investigated using leastsquares regression. Dependent variables were examined with initial treatment density and the number of survivors (for growth and condition) as the
independent variable in separate analyses.
Environmental conditions in the experimental
units were monitored periodically to document
temperature and visually assess the standing crops
of algae. Conductivity (YSI meter) was 298–358
mS on 19 November 1998 and 352–460 mS on 18
May 1999. Oxygen was presumed to be saturated
due to vigorous aeration from the return flow. Oxygen measured by YSI meter on 2 December 1998
was 10.0–10.2 mg/L, and on 18 May 1999 oxygen
was 8.7–10.6 mg/L, with all units at or slightly
above saturation. Throughout the winter, the water
remained clear, algae grew well in the streams, and
fish continued to be relatively active and to behave
normally (as viewed through Plexiglas windows
in each stream pool unit).
Algae was cleaned from downstream pump
screens as needed to maintain flow and then returned to the streams. On 2 April 1999, standing
columns of algae were removed by hand, and a
fine-mesh dip net was passed lightly over the substrate to remove standing algae. Removal of algae
simulated the effects of a spring spate, a common
event in the streams of southern Oklahoma (Gelwick and Matthews 1992; Matthews et al. 1994).
However, this artificial spate removed only upright
algae (i.e., it did not scour or deplete algae from
stone surfaces), and algae rapidly regrew in subsequent weeks.
FIGURE 1.—Percent of fish initially stocked in October
remaining at the end of the experiment in May relative
to initial stocking density.
Results
Autumnal Growth
From 29 October to 4 December, the red shiners
in the experimental units grew little. Individuals
removed from four units on 4 December averaged
22.6, 24.0, 22.8, and 22.3 mm SL per unit, for a
grand mean of 22.9 mm compared with the mean
size of wild-caught individuals (and the presumed
initial size in the experimental units) of 21.3 mm.
Thus, the red shiners in the experimental units entered cold winter weather having increased little
in size since the middle of autumn.
Overwinter Survival
Overwinter survival was negatively related to
initial density (Figure 1). Two fish were found dead
in one low-density unit (initially seven individuals) when the experiment was ended in May 1999,
but because these individuals obviously had overwintered and died just before termination of the
study we included them in the total overwinter
survival for this unit. We did not measure them
for analysis of growth because their deteriorated
condition precluded accurate measurement, but
they were relatively large individuals. The negative relationship between initial density and overwinter survival was significant at P 5 0.054 (r2 5
0.275), with no apparent threshold at which density first affected survival (Figure 1).
Growth in Winter and Spring
Mean overall growth, as indicated by the size
of individuals at the end of the experiment, was
highly density dependent. Although individuals
were not measured between December and May
to avoid disturbing the experiment, weekly obser-
482
MATTHEWS ET AL.
FIGURE 2.—Mean size of all fish remaining at the end
of the experiment in May relative to initial stocking
density (top panel) and the number surviving over winter
(bottom panel).
vations suggested that most growth took place after the onset of warm weather in March or April.
An additional field sample after our experiment
was over also supported the postulate that red shiners grow little in cold weather in the wild and exist
at high densities of small individuals in winter. On
5 February 2000, in the Washita River in Kiowa
County, Oklahoma (upstream from our original
sample site), Matthews observed a very dense
school (about 2 m in diameter) of small red shiners.
In two seine hauls (most individuals were captured
in the first haul), 894 young-of-year red shiners
were captured, of which a subsample of 200 individuals had a mean standard length of 18.3 mm
with a standard deviation of 1.8 mm. These small
individuals apparently hatched late in the warm
season (red shiners in our experimental streams
have spawned as late as October; Matthews, unpublished data), entered winter at a small size, and
grew little by February.
In our experiment, there was a strong negative
relationship (r2 5 0.777, P , 0.001) between ini-
tial density and the mean size of individuals at the
end in May (Figure 2, top panel). There was an
even stronger negative relationship (r2 5 0.84) between the mean size of individuals and the final
densities of fish at the end of the experiment (Figure 2, bottom panel). These results suggested linear rather than threshold effects of density on the
growth of red shiners. Modal size per unit also
was smaller at higher densities, and a higher proportion of individuals grew to adult size in units
with the two lowest initial densities (Figure 3). In
May, there was a strong similarity between the
length frequencies of red shiners in the higherdensity experimental units and those in the Washita
River at the site where the experimental fish were
obtained. The size-frequency distribution of 262
fish measured from those captured in the wild at
the same time fish were obtained for the experiments had a modal size range of 20–24 mm SL
(Figure 3, upper panel). Seining at the Washita
River site in May 1999 (coinciding with the termination of the experiment) showed that fish in
the wild had a modal SL in the range of 24–28
mm, matching that at the two highest initial stocking densities in the experimental systems (Figure
3, lower three panels).
Mean or modal sizes were strongly density dependent, but those values alone did not adequately
describe the more complex relationship between
density and the number of individuals that grew
to larger sizes (i.e., to a size at which sexual maturation was likely). By the end of the experiment
in May, at least a few individuals at all densities
had reached adult size (based on the minimal
known reproductive size of 29 mm SL for red shiners; Hubbs and Ortenburger 1929) and a few males
in all units had chromatic breeding colors and/or
tubercles, but there was unequal expression of
growth and maturation as a function of density. At
higher densities (initial stocking of 21.3 and 26.6
individuals/m2) most fish remained less than 28
mm SL and lacked nuptial chromatics, whereas at
low densities a higher proportion of individuals
reached a larger (adult) size (Figure 3). The magnitude of skewness at the end of the experiment
was positively related to both initial and final fish
densities (Figure 4).
Discussion
Overview
High densities of small red shiners (,25 mm SL)
are common in late autumn in central and southwestern streams. In our experimental streams, red
RED SHINER DENSITY DEPENDENCE
483
FIGURE 3.—Size distributions of individuals at each density in May (both units pooled; N 5 the number of
measured survivors) together with the size distributions of wild fish captured in the Washita River in October 1998
and May 1999 (corresponding to the times of initial stocking and final harvest of the experimental units). The
vertical line is at 29 mm, the minimal size reported in the literature for fully reproductive adults.
shiners of initially small prewinter size exhibited
density-dependent overwinter survival and mean
growth. Length-frequency distributions during May
were more skewed at high densities, at which a few
individuals reached adult size while most remained
small or subadult. The density-dependent effects on
the mean growth of red shiners in this experiment
were similar to those on other species (Crisp 1993;
Schlosser 1998; Byström and Garcia-Berthou
1999). Schlosser (1998) found decreases in the
growth of young creek chub in experimental
streams at densities from 2 to 8/m2. Density-dependent effects on population size might occur at
critical points in the annual cycle of a species.
Schlosser (1987) suggested that intraspecific competition (a density-dependent phenomenon) might
484
MATTHEWS ET AL.
30% of the variation among treatments in survival
at the end of our experiment. Although our experiment was not designed to assess the specific
mechanisms by which crowding can exert effects,
we can suggest mechanisms that might have
caused the density-dependent effects observed in
this study.
Potential Mechanisms
FIGURE 4.—Skewness of length distributions of all fish
per unit versus the initial stocking density (top panel)
and the density at the end of the experiment (bottom
panel).
limit summer growth of small fishes, with negative
effects on prewinter size and subsequent winter survival. He also provided empirical evidence that the
growth and overwinter survival of small creek chub
in a natural and an experimental stream were density dependent. Thus, evidence is mounting that in
the highly variable environments presented by
streams (Grossman et al. 1982; Peckarsky 1983)
there are times in summer, winter, or spring (in the
quite different streams from Minnesota to
Oklahoma) when density-dependent processes can
influence population parameters.
Winter is a stressful time for fish, with many
species showing little growth at cold temperatures
or high overwinter mortality (Hurst and Conover
1998; Schultz et al. 1998; Garvey et al. 1998). In
winter, energy stores can be depleted rapidly
(Thompson 1989; Schultz et al. 1998), and the
impacts of winter stressors may vary with fish size.
Small fish have higher metabolic demands and
fewer energy stores than large fish (e.g., Cargnelli
and Gross 1997). Initial density explained almost
Density-dependent effects are most often
thought to be due to intraspecific competition for
resources or to behavioral interference among individuals. Because benthic invertebrate densities
were neither related to fish density nor depleted in
any experimental units (Gido and Matthews 2001),
we suggest that direct competition for benthic prey
was not the mechanism influencing the growth or
survival of red shiners. Stomachs from red shiners
examined in December contained some winged
adults, apparently from the surface of the water,
and red shiners in a previous experiment in these
stream units also consumed a high proportion of
surface insects (Gido et al. 1999). It is possible
that density-dependent competition for surface insects influenced survival or growth, but we have
no direct data on the availability of winged adults.
Schlosser (1998) noted that competition among juvenile creek chubs at high densities might be for
nonbenthic items (i.e., drifting invertebrates) rather than for benthic insects, as the latter were not
decreased by creek chub in his experiments.
The higher percent survival observed in lowerdensity treatments could have been due to differences in growth before the onset of cold weather,
such as greater autumnal growth by individuals at
lower densities. However, our examination of fish
from two low-density and two high-density treatments in December showed no difference in autumnal growth, that is, fish in all treatments entered cold weather at about the same relatively
small size. We thus reject late-autumn growth as
a mechanism leading to greater overwinter survival in our experiment.
The density-dependent skewness in the growth
of red shiners in our study was similar to the reported variance in the size or skewness in size for
tadpoles from ephemeral ponds (Brockelman
1969; Wilbur 1997). Red shiners at higher densities had greater skewness in final body lengths
in May, suggesting growth depensation. Growth
depensation, or uneven growth within a cohort, is
well known in fishes (Wohlfarth 1977; Shelton et
al. 1979; Rubenstein, 1981; Keast and Eadie 1985;
Wootton 1990) and could be due to inequities
RED SHINER DENSITY DEPENDENCE
among individuals in initial size or dominance.
However, we controlled as much as possible for
initial size, using individuals of typical small
‘‘field’’ size to minimize the initial size-related
inequities among individuals in a unit. Thus, we
assume that the skewness in body size at the end
of the experiment was indeed related to densities
within the study period, probably during the
springtime period of growth, and not to any initial
inequities among units. One plausible explanation
for the greater skewness in body size at higher
densities is that even a slight inequity in size when
springtime growth began gave larger individuals
an advantage at capturing surface insects or similar
prey, allowing them to further outgrow and/or
deny access to surface prey by the many small
individuals.
It is also possible that behavioral interference
(e.g., Petranka 1989) could have explained the
density-dependent effects we detected. We have
observed in this study, in aquaria, and in previous
experiments (Gido et al. 1999) that red shiners are
more active and aggressive than many other minnow species, which might result in increased per
capita metabolic demand at high densities. Marchand and Boisclair (1998) showed that the growth
of trout was less at high densities due to increased
physical activity rather than to food limitation.
Implications
Although we have no rigorous estimates of red
shiner density or resource availability during winter 1998–1999 in the Washita River, the growth of
red shiners in our two highest-density treatments
was virtually identical to that of the corresponding
wild cohort during the same period of time. This
suggests that density may influence the growth of
this species in natural streams. Additionally, we
know from observations in many Oklahoma
streams, including the Washita River, that natural
densities of red shiners can be very high at times.
The potential tradeoffs and points of optimality
between the benefits of schooling (predator
swamping, etc.) and the costs of crowding (slowed
growth, etc.) are beyond the scope of this paper,
but it is clear that in spite of the potential for red
shiners to be more dispersed in streams they are
sometimes extremely crowded in natural stream
microhabitats in autumn or winter.
Because growth or body size is important to the
survival of young fish, the fecundity of adults, or
overall fitness (e.g., Schlosser 1987; Jenkins et al.
1999), our findings may be important in understanding the population dynamics of red shiners
485
and other small fish species in harsh southwestern
streams. Eisenberg (1966) found that snails in the
wild were ‘‘realizing only a portion of their potential for fecundity and growth,’’ and a similar
conclusion might apply to red shiners at high density, which would have important consequences
for their life history, given that body size is well
known to influence fecundity, egg size, and other
critical parameters of reproduction in fishes (Roff
1992). Slowed growth also means that individuals
will remain vulnerable to predators like small sunfish Lepomis sp., which are common in many
streams having red shiners, for a longer period of
time.
In harsh environments, where population size
can be strongly or rapidly affected by abiotic
events (Grossman et al. 1982; Peckarsky 1983;
Pianka 2000), density-dependent effects might be
expected to influence the life history of a species
less frequently. For example, Jennings and Philipp
(1994) showed that the relative importance of
density-dependent and density-independent effects on sunfish reproduction in streams was dependent on the hydrology within a year. We
found density-dependent effects on the overwinter survival and growth patterns for red shiners, suggesting that when populations of this
species are dense (e.g., in years with stable flow
patterns or those lacking abiotic disturbance) vital population rates may be density dependent.
Density-dependent effects on a population’s vital rates (natality, individual growth, and mortality) are requisite (if not sufficient) conditions for
density-dependent regulation of population growth,
which, although long controversial (Nicholson
1933, 1957; Andrewartha and Birch 1954), remains important to understanding population and
community ecology (Murdoch 1994; Cappuccino
1995; Harrison and Cappuccino 1995; Turchin
1995; Cappuccino and Harrison 1996; Wilbur
1997). Many authors now accept that both densitydependent and density-independent processes can
be important in population or community dynamics (Jennings and Phillipp 1994; Murdoch 1994;
Brown 1995; Cappuccino 1995; Cappuccino and
Harrison 1996; Jenkins et al. 1999) and that they
can operate simultaneously and with interactions
(e.g., Ostfeld and Canham 1995). The density of
local red shiner populations must be regulated at
times by abiotic factors, when the effects of biotic
interactions are overridden by spates, drought, or
other disturbances to the system. However, the present experiment makes it clear that species in central and southwestern streams can exhibit density-
486
MATTHEWS ET AL.
dependent effects on survival and/or growth, suggesting, as did Schlosser (1987), the potential for
density-dependent effects to regulate population
size for fish even in harsh, unpredictable environments.
In addition to its theoretical interest, this finding
has implications for managers responsible for fishes or stream ecosystems in arid central and southwestern environments. To the extent that red shiners may be a model for other small stream fishes
of the region, including numerous threatened or
endangered species, managers should be aware
that decisions affecting the availability of instream
water may have direct implications for the crowding of individuals, with density-dependent effects
on growth or survival of individuals in populations
occupying altered habitats. Prudent management
for fishes in arid-land streams would suggest taking a conservative approach, providing stream
flows that mimic the natural hydrologic regime as
much as possible so that the natural densities of
individuals can be maintained.
Acknowledgments
We thank Andrew Marsh and Rebecca Marsh
for help in setting up the experiment, Donna Cobb
and Richard Page for assistance with experiment
maintenance, and Kerri Pratt for help in the field.
Stephen T. Ross, Isaac J. Schlosser, and an anonymous reviewer provided helpful critiques of the
manuscript. Logistical support for this study was
provided by the University of Oklahoma Biological Station.
References
Andrewartha, H. G., and L. C. Birch. 1954. The distribution and abundance of animals. University of Chicago Press, Chicago, Illinois.
Baltz, D. M., J. W. Fleeger, C. F. Rakocinski, and John
N. McCall. 1998. Food, density, and microhabitat:
factors affecting growth and recruitment potential
of juvenile saltmarsh fishes. Environmental Biology
of Fishes 53:89–103.
Boisclair, D., and W. C. Leggett. 1989. Among-population
variability of fish growth: III. Influence of fish community. Canadian Journal of Fisheries and Aquatic
Sciences 46:1539–1550.
Brett, J. R. 1979. Environmental factors and growth.
Pages 599–675 in W. S. Hoar, D. J. Randall, and J.
R. Brett editors. Fish physiology, volume 8. Academic Press, New York.
Brockelman, W. Y. 1969. An analysis of density effects
and predation in Bufo americanus tadpoles. Ecology
50:632–644.
Brown, J. H. 1995. Macroecology. University of Chicago Press, Chicago, Illinois.
Byström, P., and E. Garcı́a-Berthou. 1999. Density de-
pendent growth and size specific competitive interactions in young fish. Oikos 86:217–232.
Cargnelli, L. M., and M. R. Gross. 1997. Fish energetics: larger individuals emerge from winter in better
condition. Transactions of the American Fisheries
Society 126:153–156.
Cappuccino, N. 1995. Novel approaches to the study of
population dynamics. Pages 3–16 in N. Cappuccino
and P. W. Price, editors. Population dynamics: new
approaches and synthesis. Academic Press, San Diego, California.
Cappuccino, N., and S. Harrison. 1996. Densityperturbation experiments for understanding population regulation. Pages 53–64 in R. B. Floyd, A.
W. Sheppard, and P. J. De Barro, editors. Frontiers
of population ecology. CSIRO Publishing, Melbourne, Australia.
Crisp, D. T. 1993. Population densities of juvenile trout
(Salmo trutta) in five upland streams and their effects upon growth, survival, and dispersal. Journal
of Applied Ecology 30:759–771.
Cross, F. B., and J. T. Collins. 1975. Fishes in Kansas.
University of Kansas Museum of Natural History,
Public Education Series No. 3., University of Kansas, Lawrence, Kansas.
Dong, Q., and D. L. DeAngelis. 1998. Consequences of
cannibalism and competition for food in a smallmouth bass population: an individual-based modeling study. Transactions of the American Fisheries
Society 127:174–191.
Dunson, W. A., and D. B. Dunson. 1999. Factors influencing growth and survival of the killifish, Rivulus
marmoratus, held inside enclosures in mangrove
swamps. Copeia 1999:661–668.
Eisenberg, R. M. 1966. The regulation of density in a
natural population of the pond snail, Lymnaea elodes. Ecology 47:889–906.
Garvey, J. E., R. A. Wright, and R. A. Stein. 1998.
Overwinter growth and survival of age-0 largemouth bass (Micropterus salmoides): revisiting the
role of body size. Canadian Journal of Fisheries and
Aquatic Sciences 55:2414–2424.
Gelwick, F. P., and W. J. Matthews. 1992. Effects of an
algivorous minnow on temperate stream ecosystem
properties. Ecology 73:1630–1645.
Gido, K. B., and W. J. Matthews. 2001. Ecosystem effects of water column minnows in experimental
streams. Oecologia 126:247–253.
Gido, K. B., and D. L. Propst. 1999. Habitat use and
association of native and nonnative fishes in the San
Juan River, New Mexico and Utah. Copeia 1999:
321–332.
Gido, K. B., J. F. Schaefer, K. Work, P. W. Lienesch, E.
Marsh-Matthews, and W. J. Matthews. 1999. Effects of red shiner (Cyprinella lutrensis) on Red River pupfish (Cyprinodon rubrofluviatilis). Southwestern Naturalist 44:287–295.
Gilliam, J. F., D. F. Fraser, and A. M. Sabat. 1989. Strong
effects of foraging minnows on a stream benthic
invertebrate community. Ecology 70:445–452.
Goldberg, D. E., and S. M. Scheiner. 1993. ANOVA
and ANCOVA: field competition experiments. Pag-
RED SHINER DENSITY DEPENDENCE
es 69–93 in S. M. Scheiner and J. Gurevitch, editors.
Design and analysis of ecological experiments.
Chapman and Hall, New York.
Grossman, G. D., P. B. Moyle, and J. O. Whittaker, Jr.
1982. Stochasticity in structural and functional
characteristics of an Indiana stream fish assemblage:
a test of community theory. American Naturalist
120:423–454.
Harvey, B. C. 1987. Susceptibility of young-of-the-year
fishes to downstream displacement by flooding.
Transactions of the American Fisheries Society 116:
851–855.
Harrison, S., and N. Cappuccino. 1995. Using densitymanipulation experiments to study population regulation. Pages 131–147 in N. Cappuccino and P. W.
Price, editors. Population dynamics: new approaches and synthesis. Academic Press, San Diego, California.
Hefley, H. M. 1937. Ecological studies on the Canadian
River floodplain in Cleveland County, Oklahoma.
Ecological Monographs 7:345–402.
Hubbs, C. L., and A. I. Ortenburger. 1929. Fishes collected in Oklahoma and Arkansas in 1927. University of Oklahoma Biological Survey 1:45–112.
Hurst, T. P., and D. O. Conover. 1998. Winter mortality
of young-of-the-year Hudson River striped bass
(Morone saxatilis): size-dependent patterns and effects on recruitment. Canadian Journal of Fisheries
and Aquatic Sciences 55:1122–1130.
Jenkins, T. M., Jr., S. Diehl, K. W. Kratz, and S. D.
Cooper. 1999. Effects of population density on individual growth of brown trout in streams. Ecology
80:941–956.
Jennings, M. J., and D. P. Philipp. 1994. Biotic and
abiotic factors affecting survival of early life history
intervals of a stream-dwelling sunfish. Environmental Biology of Fishes 39:153–159.
Keast, A., and J. M. Eadie. 1985. Growth depensation
in the year-0 largemouth bass: the influence of diet.
Transactions of the American Fisheries Society 114:
204–213.
Johnson, T. B., and D. O. Evans. 1996. Temperature
constraints on overwinter survival of age-0 white
perch. Transactions of the American Fisheries Society 125:466–471.
McCann, K. 1998. Density-dependent coexistence in
fish communities. Ecology 79:2957–2967.
Marchand, F., and D. Boisclair. 1998. Influence of fish
density on the energy allocation pattern of juvenile
brook trout (Salvelinus fontinalis). Canadian Journal
of Fisheries and Aquatic Sciences 55:796–805.
Marsh-Matthews, E., and W. J. Matthews. 2000. Geographic, terrestrial, and aquatic factors: which most
influence structure of stream fish assemblages in the
midwestern United States? Ecology of Freshwater
Fish 9:13–21.
Matthews, W. J. 1977. Influence of physicochemical factors on habitat selection by red shiners, Notropis
lutrensis (Pisces: Cyprinidae). Doctoral dissertation. University of Oklahoma, Norman, Oklahoma.
Matthews, W. J. 1980. Notropis lutrensis (species account). Page 285 in D. S. Lee, C. R. Gilbert, C. H.
487
Hocutt, R. E. Jenkins, D. E. McAllister, and J. R.
Stauffer, Jr., editors. Atlas of freshwater fishes of
North America. North Carolina State Museum, Raleigh, North Carolina.
Matthews, W. J. 1987. Physicochemical tolerance and
selectivity of stream fishes as related to their geographic ranges and local distributions. Pages 111–
120 in W. J. Matthews and D. C. Heins, editors.
Ecology of North American stream fishes. University of Oklahoma Press, Norman, Oklahoma.
Matthews, W. J. 1988. North American prairie streams
as systems for ecological study. Journal of the North
American Benthological Society 7:387–409.
Matthews, W. J. 1998. Patterns in freshwater fish ecology. Chapman and Hall, New York.
Matthews, W. J., and L. G. Hill. 1979. Influence of
physico-chemical factors on habitat selection by red
shiners, Notropis lutrensis (Pisces: Cyprinidae).
Copeia 1979:70–81.
Matthews, W. J., and L. G. Hill. 1980. Habitat partitioning in the fish community of a southwestern
river. Southwestern Naturalist 25:51–66.
Matthews, W. J., and E. G. Zimmerman. 1990. Potential
effects of global warming on native fishes of the
southern Great Plains and the Southwest. Fisheries
15:26–32.
Matthews, W. J., B. C. Harvey, and M. E. Power. 1994.
Spatial and temporal patterns in the fish assemblages of individual pools in a midwestern stream
(USA). Environmental Biology of Fishes 39:381–
397.
Michaletz, P. H. 1997. Factors affecting abundance,
growth, and survival of age-0 gizzard shad. Transactions of the American Fisheries Society 126:84–
100.
Morin, P. J. 1986. Interactions between intraspecific
competition and predation in an amphibian predator2prey system. Ecology 67:713–720.
Murdoch, W. W. 1970. Population regulation and population inertia. Ecology 51:497–502.
Nicholson, A. J. 1933. The balance of animal populations. Journal of Animal Ecology 2:132–178.
Nicholson, A. J. 1957. The self-adjustment of populations to change. Cold Spring Harbor Symposium in
Quantitative Biology 22:153–173.
Ostfeld, R. S., and C. D. Canham. 1995. Densitydependent processes in meadow voles: an experimental approach. Ecology 76:521–532.
Palmer, M. A., and D. L. Strayer. 1996. Meiofauna.
Pages 3152337 in F. R. Hauer and G. A. Lamberti,
editors. Methods in stream ecology. Academic
Press, San Diego, California.
Peckarsky, B. L. 1983. Biotic interactions or abiotic
limitations? A model of lotic community structure.
Pages 3032323 in T. D. Fontaine III, and S. M.
Bartell, editors. Dynamics of lotic ecosystems. Ann
Arbor Science, Ann Arbor, Michigan.
Petranka, J. W. 1989. Density-dependent growth and
survival of larval Ambystoma: evidence from wholepond manipulations. Ecology 70:1752–1767.
Petranka, J. W., and A. Sih. 1986. Environmental instability, competition, and density-dependent
488
MATTHEWS ET AL.
growth and survivorship of a stream-dwelling salamander. Ecology 67:729–736.
Pianka, E. R. 2000. Evolutionary ecology, 6th edition.
Addison Wesley Longman, San Francisco, California.
Power, M. E., and A. J. Stewart. 1987. Disturbance and
recovery of an algal assemblage following flooding
in an Oklahoma stream. American Midland Naturalist 117:333–345.
Power, M. E., W. J. Matthews, and A. J. Stewart. 1985.
Grazing minnows, piscivorous bass, and stream algae: dynamics of a strong interaction. Ecology 66:
1448–1456.
Rodenhouse, N. L., T. W. Sherry, and R. T. Holmes.
1997. Site-dependent regulation of population size:
a new synthesis. Ecology 78:2025–2042.
Roff, D. A. 1992. The evolution of life histories: theory
and analysis. Chapman and Hall, New York.
Rubenstein, D. I. 1981. Individual variation and competition in the Everglades pygmy sunfish. Journal
of Animal Ecology 50:337–350.
Saski, A., and G. de Jong. 1999. Density dependence
and unpredictable selection in a heterogeneous environment: compromise and polymorphism in the
ESS reaction norm. Evolution 53:1329–1342.
Schlosser, I. J. 1987. A conceptual framework for fish
communities in small warmwater streams. Pages
17–24 in W. J. Matthews and D. C. Heins, editors.
Community and evolutionary ecology of North
American stream fishes. University of Oklahoma
Press, Norman, Oklahoma.
Schlosser, I. J. 1998. Fish recruitment, dispersal, and
trophic interactions in a heterogeneous lotic environment. Oecologia 113:260–268.
Schmitt, R. J., and S. J. Holbrook. 1999. Mortality of
juvenile damselfish: implications for assessing processes that determine abundance. Ecology 80:35–
50.
Schultz, E. T., D. O. Conover, and A. Ehtisham. 1998.
The dead of winter: size-dependent variation and
genetic differences in seasonal mortality among Atlantic silversides (Atherinidae: Menidia menidia)
from different latitudes. Canadian Journal of Fisheries and Aquatic Sciences 55:1149–1157.
Semlitsch, R. D. 1987a. Paedomorphosis in Ambystoma
talpoideum: effects of density, food, and pond drying. Ecology 68:994–1002.
Semlitsch, R. D. 1987b. Density-dependent growth and
fecundity in the paedomorphic salamander Ambystoma talpoideum. Ecology 68:1003–1008.
Shelton, W. L., W. D. Davies, T. A. King, and T. J.
Timmons. 1979. Variation in the growth of the initial year-class of largemouth bass in West Point Reservoir, Alabama and Georgia. Transactions of the
American Fisheries Society 108:142–149.
Smith, H. T., C. B. Schreck, and O. E. Maughn. 1978.
Effect of population density and feeding rate on the
fathead minnow (Pimephales promelas). Journal of
Fish Biology 12:449–455.
Sokal, R. R., and F. J. Rohlf. 1995. Biometry, 3rd edition. W. H. Freeman Co., New York.
Starrett, W. C. 1951. Some factors affecting the abundance of minnows in the Des Moines River, Iowa.
Ecology 32:13–27.
Stewart, A. J. 1987. Responses of stream algae to grazing minnows and nutrients: a field test for interactions. Oecologia 72:1–7.
Tamarin, R. H. 1978. Population regulation. Dowden,
Hutchison, and Ross, Inc., Stroudsburg, Pennsylvania.
Thompson, J. M. 1989. The role of size, condition, and
lipid content in the overwinter survival of age-0
Colorado squawfish. Master’s thesis. Colorado State
University, Fort Collins.
Turchin, P. 1995. Population regulation: old arguments
and a new synthesis. Pages 10–40 in N. Cappuccino
and P. W. Price, editors. Population dynamics: new
approaches and synthesis. Academic Press, San Diego, California.
Vaughn, C. C., F. P. Gelwick, and W. J. Matthews. 1993.
Effects of algivorous minnows on production of
grazing stream invertebrates. Oikos 66:119–128.
Wedemeyer, G. A. 1997. Effects of rearing conditions
on the health and physiological quality of fish in
intensive culture. Pages 3–6 in G. K. Iwama, A. D.
Pickering, J. P. Sumpter, and C. B. Schreck, editors.
Fish stress and health in aquaculture. Cambridge
University Press, Cambridge, UK.
Welker, M. T., C. L. Pierce, and D. H. Wahl. 1994.
Growth and survival of larval fishes: roles of competition and zooplankton abundance. Transactions
of the American Fisheries Society 123:703–717.
Wohlfarth, G. W. 1977. Shoot carp. Bamidgeh 29:35–
56.
Wilbur, H. M. 1977. Density-dependent aspects of
growth and metamorphosis in Bufo americanus.
Ecology 58:196–200.
Wilbur, H. M. 1997. Experimental ecology of food
webs: complex systems in temporary ponds. Ecology 78:2279–2302.
Wootton, R. J. 1990. Ecology of teleost fishes. Chapman
and Hall, London.