1. 1
The Effect of Pool Geomorphology on Feeding Morphology of Aplodinotus
grunniens and Lepomis macrochirus in the Ohio River, USA.
A Capstone Project Submitted to
the Graduate Faculty of
Kentucky State University
in Partial Fulfillment of the
Requirements for the Degree of
Master of Environmental Studies from
Division of Environmental Studies and Sustainable Systems
Frankfort, Kentucky
May 4, 2012
Except where reference is made to the work of others, the work described in this
capstone project is my own or was done in collaboration with my advisory committee.
_____________________________
Adam Gerughty
Certificate of Approval:
__________________________
Dr. Tamara Sluss, Associate Professor of Biology
College of Arts and Sciences
__________________________
Dr. Michael Bomford, Extension Specialist
College of Agriculture, Food Science and Sustainable Systems
__________________________
Dr. Kazi Javed, Associate Professor of Chemistry
MES Program Coordinator
____________________
Dr. Teferi Tsegaye, Dean
College of Agriculture, Food Science and Sustainable Systems

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Abstract
The Ohio River is over 1,500 kilometers long with 20 navigational dams
segmenting it into navigational pools. This study was conducted to determine the
effects of navigational dams on feeding morphology for two predatory fish, freshwater
drum, A. grunniens (n=155) and bluegill, L. macrochirus (n=45) in pools with differing
geomorphology using specimens from the Cincinnati Natural History Museum. Feeding
parameters such as jaw length and gap width of the mouth were ascertained using a
Nikon D90 digital camera and SPOT Advance for each individual fish. Parameters were
then analyzed with principle component analysis by PC-ORD. According to this study,
the A. grunniens' morphological parameters are less similar for individuals in the semi-
constricted glaciated valley compared to individuals that inhabit the alluvial valley and
upper Ohio River. The L. macrochirus' feeding morphology is more similar between
individuals in the semi-constricted glaciated valley and upper the Ohio River. The
influencing morphological measurement was jaw length; A. grunniens jaw length mean
was 0.273cm L macrochirus jaw length mean was 0.228cm.
Introduction
River Concepts
Ecology of lotic systems has been studied throughout the years to determine
ecosystem processes, community organization, biodiversity, and primary production.
As a result, several concepts have been formulated including the River Continuum
Concept (RCC) (Vannote et al. 1980), the Flood Pulse Concept (FPC) (Junk et al.
1989), and the Inshore Retention Concept (IRC) (Schiemer et. al. 2001).
The River Continuum Concept states that as stream order increases the main
source of production changes, causing each stream order to have a different variety of
organisms. The organisms are dependent on allochthonous materials from upstream
(Vannote et al. 1980). The RCC does not take into account that larger order streams
have floodplains which organisms can utilize seasonally.
The Flood Pulse Concept states that pulsing river discharge has a greater impact
on food webs and supports allochthonous materials from the floodplain and not just
from production in the riparian zone (Junk et al. 1989). The terrestrial plants add
nutrients in the soil during the dry season and during the wet season the river flows into
its floodplain; exchanging nutrients within the plain. Without this lateral exchange, the
biota in the river would have trouble receiving the necessary nutrients. Fish can also
use the floodplain to feed on the abundant food contained within the floodplain and use
it as a safe haven for growth and development (Junk et al. 1989).

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One of the most recent concepts developed is the Inshore Retention Concept
(Schiemer et al. 2001). IRC explains how biota and production levels change based on
the river water retention, meaning the water velocity or discharge controls the biotic
diversity and production levels. When water velocity is low during late summer, around
islands and bars, near shores, and in the floodplains, the autochthonous productivity will
increase (Schiemer et al. 2001). The phytoplankton will not be washed downriver and
will be able to stay near the surface to receive sunlight. The low discharge also allows
for increased interaction between biota. Water velocity is high during spring, times of
flooding, and near rapids and open waters. Phytoplankton are washed away and thus
not able to stay near the surface; they cannot receive the necessary sunlight causing
production to decrease. The combination of high velocity and low production causes a
decrease in biota interactions in the food web, reducing diversity (Schiemer et al. 2001).
Natural History of the Ohio River
The Ohio River is North America’s fourth largest river, in terms of discharge
(Thorp and Mantovani 2005). The Ohio River is 1,579 km long and connects with the
Mississippi River at Cairo, Illinois. It is the largest tributary of the Mississippi River, with
a drainage basin is 517,998 km2. The Ohio River was formed when the Monongahela
and Allegheny rivers converged in Pennsylvania. This confluence is not the modern
day flow pattern of the Ohio River; part of the river has been modified. Throughout the
centuries different glaciers carved the valleys that the river flows through today (Ray
1974).
The Ohio River is classified into two main sections, the upper Ohio River and the
lower Ohio River. The upper Ohio River is from river kilometer 708 to the headwaters
and is contained in the unglaciated Allegheny plateau. The upper Ohio River has a vast
flood plain, due to an alluviated valley, which periodically floods during the spring
months. The lower river is further broken down into three geological sections, from
Cincinnati, OH to Louisville, KY the river valley is considered to be glaciated valley, from
river kilometer 1006 to river kilometer 1167 the river valley is a constricted valley, and at
river kilometer 1167 to the end of the Ohio River the valley is alluviated (Ray 1974).
These valleys are geologically different from each other and affect the Ohio River
floodplain.
The glaciated valley was modified by four major glaciers during the Quaternary
time period. The first glacier was the Nebraskan ice sheet, followed by the Kansan, the
Illinioan, and the Wisconsin. The movement and melting of these ice sheets modified
the flow and drainage pattern of the Ohio River. The Wisconsin, Nebraskan, and
Kansan ice sheets reached far enough down to modify the actual valley, while the
melting of the Illinioan ice sheet altered drainage patterns into the Ohio River, resulting
in a narrow channel with steep banks and a narrow floodplain (Ray, 1974).

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The constricted valley is similar to the glaciated valley, with deep valley walls and
a narrow valley bottom (Ray, 1974). The floodplain in this valley is almost nonexistent,
so river flooding is rare.
The final part of the Ohio River Valley is the unglaciated alluviated valley. This
valley has extensive bottomlands and low rounded valley walls. There a few sectors
that are narrow and have steeps walls, but most of the valley is alluviated (Ray 1974).
The unglaciated, alluviated valley regularly floods its banks, similar to the Upper Ohio
River valley.
Like most major modern rivers, the Ohio River is dammed to help control
seasonal flooding and maintain minimum water levels for barge traffic (US Army Corps
of Engineers Pittsburgh District 2012). The Ohio River contains 20 navigational dams
which have channelized it and artificially control the flood stages (Ray, 1974). Water
pools behind the dam, each pool has upstream riverine characteristic, high water
velocity, and a downstream lacustrine like portion just above the dam (Wetzel 2001).
Most dams were constructed during the 1960's and 1970's with the oldest dam dating
from 1929.
Life History Traits of Aplodinotus grunniens and Lepomis macrochirus
Two species in the Ohio River that could be affected by navigational dams are
Aplodinotus grunniens and Lepomis macrochirus. A. grunniens is abundant in large
lakes and rivers with warm open waters and a muddy benthic zone, like the Ohio River.
They can tolerate water temperature above 26° C and endure low dissolved oxygen
levels for an extended period of time (Wallus and Simon 2006). A. grunniens relies on
sight to feed, and has been observed hunting for prey in all hours of day and night.
Young individuals feed low on the food chain, feasting on copepods and cladocerans.
As they grow in size, they will start to move up the food chain, feeding on fish, crayfish,
and mollusks. A. grunniens seldom grow over 11 kg in the Ohio River. The average life
span is about 10 years of age, but some individuals can live as long as 17 years.
(Priegel 1967) A grunniens tend to travel downstream in large rivers and can have
home ranges up to 160 km. (Wallus and Simon 2006)
L. macrochirus is a warm water species that can be found among the weeds
along lakes and river banks. It can tolerate water temperatures up to 35° C and cannot
tolerate low dissolved oxygen levels (Spotte 2007). L. macrochirus is one of the first
species to experience mortality when dissolved oxygen decreases. Young fish will feed
on plankton, small copepods and cladocerans; as they grow they start to eat larger
prey, such as insects and the occasional frog or fish. Their primary food source is
surface insects. L. macrochirus swims around the weeds and observes the surface,
watching for insects. When it spots potential prey it will swim near the surface and suck

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the insect into its mouth. Most L. macrochirus weigh less than 1.8 kg and have an
average life span of 7 years (Snow et al. 1960).
Like all species in an ecosystem, A. grunniens and L. macrochirus compete for
food, and must sometimes select food outside their traditional prey size and niche. One
study showed that Oncorhynchus mykiss and Perca flavescens select for larger daphnia
and leave the smaller daphnia alone when the species were separated. Once the O.
mykiss and P. flavescens are introduced into the same lake, larger daphnia are
eliminated and smaller zooplankton are selected. Both species must eat smaller prey
and select from different niches. (Galbraith 1967)
Objectives
This study was conducted to compare the mouth morphology of two species of
fish between navigational sites in three different geomorphologic areas on the Ohio
River. The two predatory fish selected for this study were L. macrochirus and A.
grunniens. These fish species could be separated by their mouth morphology
measurements such as gape width, head length, and mouth height (Labropoulou and
Eleftheriou 1996). It is possible that because the river continuity has been altered by
navigational dams, individual L. macrochirus and A. grunniens are selecting different
prey at different sites. If prey selection has been altered changes will show in the mouth
morphology. Due to the geomorphology of the dams a lack of floodplain accessibility
could lead to a change in individuals' diets. Competition within the Ohio River could
explain a change in prey selection; if it has been altered changes will be exhibited in
mouth morphology.
Specimen collectionmethods
Specimens for this project were obtained from the Cincinnati Natural History
Museum's preserve ichthyology collection. Each specimen was collected by
electrofishing during the years of 1967, 1991 1992, and 1993, during time of collection
the site was exhausted The specimens were then preserved in a solution of 95%
ethanol in a container that had a specific ID number, information on location, collection
date, method of collection, and lot number. If there was more than one specimen
contained in a container, additional identification labels were assigned.
Each specimen was taken out of its container and dried for five minutes before
the mass was recorded with a digital scale. After the mass was recorded, three
different types of pictures were captured. A picture was captured with the fish on its left
side making sure the head and tail were in the frame. A 2 cm caliper was added to the
picture for reference for future measurements. An additional picture was captured of
the dorsal side of the head also with the 2 cm caliper. Multiple pictures were captured
for quality control. The pictures were captured with a Nikon D90 digital camera

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ascertained the pictures. Each picture was captured from a distance of 1 meter from
the specimen. A. grunniens (n=155) and L. macrochirus (n=45) were utilized.
Data Collection
After the pictures were uploaded into a HP Pavilion dv6 laptop, the best quality of
picture was selected for data collection. There were a total of 310 pictures of A.
grunniens and 90 pictures of L. macrochirus selected. Each picture was then uploaded
into Spot Advance version 4.7 imaging software (Diagnostic Instruments Inc.). Each
picture was calibrated and calibrations were saved for future use.
Ten morphological measurements were recorded using Spot Advance. The first
measurement was the maximum standard length, a straight line measurement from the
lower jaw to the end of the lateral line. Fork length was measured from the lower jaw to
the middle of the caudal fin. Maximum total length (Figure 1) was a straight line
measurement from the lower jaw to the tip of the caudal fin (Anderson and Neumann
1996).
The other seven morphological parameters were adapted from basic fish
measurement image (Schluter 2012). The body depth was a straight line measurement
from dorsal side to ventral side of the fish, where this distance is the greatest. The head
length was a straight line measurement from the snout to the end of the pectoral fin.
The eye diameter was a straight line measurement from the outer edge of the eye to the
opposite edge. The snout length was a straight line measurement from snout to the
front of the eye. The jaw length was a straight line measurement from the snout to the
end of the jaw. The head depth was a straight line measurement from ventricle side of
the head to the dorsal side of the head. This was measured where the distance was the
greatest. The last morphological measurement was the gap width of the mouth. This
was a straight line measurement of the widest portion of the jaw. The top down picture
of the head had to be used for this measurement (Figure 3). In total, there were 11
different morphological measurements, including mass, for A. grunniens and L.
macrochirus.
Data Analysis
Using the morphological measurements, 20 different ratios were created for
standardization between individuals. The jaw length and gape width of the mouth were
standardized. The jaw length standardization was divided by each of the ten different
morphological measurements, from mass to gape width of the mouth for each
individual. The gape width of mouth standardizations were calculated the same way.
These ratios were separated by the individual's navigational pool location and grouped
by species of fish. A. grunniens and L. macrochirus were analyzed separately.

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Statistical analyses were not preformed on the minimum, maximum, mean, and
standard deviation values for morphological characteristics along each individual
because this was not the goal of this study. This study was conducted to compare
individual mouth morphology between individuals at different navigational pool sites to
see if there any noticeable patterns between individuals at those sites.
Principle component analyses (PCA) was used to determine whether patterns in
the jaw length standardization and gap width standardization were dissimilar among the
different navigational sites for each species. PCAs were conducted for each species
separately using the 20 different mouth morphology standardizations to ascertain if the
standardizations influence the two species differently (PC-ORD v 4.25). The 20
characteristics were: jaw length to mass, jaw length to maximum standard length, jaw
length to fork length, jaw length to maximum total length, jaw length to body depth, jaw
length to head length, jaw length to eye diameter, jaw length to snout length, jaw length
to head depth, jaw length to gape width, gape width to mass, gape width to maximum
standard length, gape width to fork length, gape width to maximum total length, gape
width to body depth, gape width to head length, gape width to eye diameter, gape width
to snout length, gape width to head depth, and gape width to jaw length. Pearson
correlations between mouth standardizations and principle components scores for each
navigational pool were used to understand the driving standardization in the plots.
Bonferroni-correct probabilities were used to determine the statistical significance for
these Pearson correlations (Systat 10.2). Tukey HSD multiple comparison probabilities
were preformed to assess the statistical significance difference between navigational
pool sites (Systat 10.2).
Results
Descriptive Statistics
There were ten different navigational pools that contained A. grunniens (Table 1)
(Figure 4). The greatest river kilometer distance between individuals was 1,288 km.
Pike Island Pool, Willow Island Pool, Belleview Pool, R.C Byrd Pool, and Greenup Pool
are located in the upper Ohio River valley. Markland Pool and McApline Pool are
contained in the lower Ohio River glaciated valley. Cannelton Pool is enclosed in the
constricted valley; Newburgh Pool and Uniontown Pool are located in the lower Ohio
River alluviated valley. There were six different navigational pools that contained L.
macrochirus (Table 2) (Figure 4). The greatest river kilometer between individuals was
1,287 km. The six pools were Pike Island Pool, Willow Island Pool, Greenup Pool,
Markland Pool, Newburgh Pool, and Uniontown Pool.
A. grunniens had a mean mass of 2.786g. Mean of maximum total length was
5.441cm. The head length was 1.372cm. Lastly, the mean jaw lenght was 0.273cm

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and gape width of the mouth mean was 0.424cm (Figure 5). L. macrochirus had a
mean mass of 6.009g. The mean maximum total length was 5.605cm. Mean of head
length was 1.471cm. Lastly the mean jaw length was 0.228cm and mean gape width of
the mouth was 0.445cm (Figure 6).
Mouth morphology standardizations
Principal component analysis was used to differentiate the mouth morphology
standardization in A. grunniens and L. macrochirus. Plotting either PCA 2 or PCA 3
against PCA 1 showed no apparent clustering of individual navigational pools (Figure
7a,b). Multiple comparison probabilities verified that there was no significant difference
between navigational pools (p=0.48 and p=0.1, respectively).
The principal component analysis of the mouth morphology standardizations for
L. macrochirus found that 79.4% of the variation in the standardization data of the six
navigational pools was contained in the first three axes. PCA 1, 2, and 3 explained
39.4%, 25.5%, and 14.5% of the total variations in the mouth morphology
standardization data, respectively (Table 3).
The variables that most strongly correlated with PCA 1 were jaw length to
maximum standard length, jaw length to fork length, jaw length to maximum total length,
jaw length to body depth, jaw length to head depth, and jaw length to gape width of the
mouth. Each of these mouth morphological ratios was positively correlated with PCA 1.
Gape width of the mouth to jaw length was a strong negative correlation with PCA 1.
PCA 2 was correlated the strongest with gape width to maximum standard length, gape
width to fork length, gape width to maximum standard length, and gape width to body
depth. These variables were positively correlated along PCA 2. Jaw length to mass
and gape width to mass had a strong positive correlation with PCA 3 (Table 4).
When the principle components analysis scores were graphed (PCA 1 vs. PCA
2), there was not an apparent separation from the different navigational pools (Figure
16a). Multiple comparison probabilities verified there were no significant differences
between the navigational pool sites (p=.48). PCA 1 versus PCA 3 also showed no
visual separation between the navigational pool sites (Figure16b). Multiple comparison
probabilities verified that there was no significant difference between the navigational
pool sites (p=0.1).
The principal component analysis of the mouth morphology standardizations for
A. grunniens resulted in 79.41% of the variation in the standardization data of the ten
navigational pools was contained in the first three axes. The first Principal Component
Analysis (PCA 1) explained 38.6% of the total variations in the mouth morphology
standardization data. PCA 2 explained 23.1% of the total variations in the mouth

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morphology standardization data and PCA 3 explained 10.01% of the total variation in
the mouth morphology standardization data (Table 5).
The variables that most strongly correlated with PCA 1 were jaw length to
maximum standard length, jaw length to fork length, jaw length to head length, jaw
length to head depth, and jaw length to gape width. These standardizations were
positively correlated. Gape width to jaw length was strongly negative correlated with
PCA 1. The variables that mostly strongly correlated with PCA 2 were gape width to
maximum standard length, gape width to fork length, and gape width to mouth length.
These variables were negatively correlated with PCA 2. There were no strong
correlations with PCA 3 (Table 6).
When the principle component scores were graphed (PCA 1 vs. PCA 2) for A.
grunniens, individuals in the McApline pool individuals were separated from individuals
in the Newburgh Pool, R.C Byrd Pool, and Uniontown Pool along PCA 1. Newtown
Pool was separated from Pike Island Pool and Pike Island Pool was separated from R.C
Byrd Pool and Uniontown Pool (Figure 8a). Multiple comparison probabilities verified
that there significant difference between the navigational pools (p<.0001). PCA 1
versus PCA 3 showed no visual separation between the navigational pools (Figure 8b).
Multiple comparison probabilities verified that there were no significant differences
(p=0.11).
Mean and Standard Deviation for Aplodinotus grunniens across all sites
Mean and maximum standard deviations graphs for A. grunniens were created to
compare the six strongest correlated mouth morphology standardizations with PCA 1
between the ten different navigational dam sites. Cannelton navigational pool had the
highest mean for jaw length to maximum standard length, which was 0.08. Markland
Pool had lowest mean of 0.045. McApline Pool and Pike Island Pool had the second
lowest mean of 0.056 (Figure 9a). The site with highest standard deviation was the
Uniontown navigational pool, which was 0.0247. The sites with lowest standard
deviations were the Willow Island Pool and Markland Pool. Their standard deviations
were 0.00349 and 0.0045 respectively (Figure 9b). It is important to note that in these
graph there were was only one individual in the Cannelton Pool, hence the reason there
is no standard deviation and there were only two individuals contain in the Willow Island
Pool and Markland Pool.
The highest mean for jaw length to fork length was found at Cannelton
navigational Pool, the mean was 0.071. The lowest mean was 0.041, which was the
Markland Pool site. McApline Pool, Greenup Pool, and Belleview Pool all had similar
means (Figure 10a). Uniontown Pool the highest standard deviation of 0.022. The
lowest standard deviations were 0.0044 for Markland Pool and .0004 for Willow Island

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Pool. There was a significant difference between McApline Pool and Uniontown Pool
(Figure 10b).
Cannelton Pool had the highest jaw length to maximum standard length of 0.064.
Uniontown Pool and Newburgh Pool had the same mean of 0.057. McApline Pool,
Greenup Pool, R.C Byrd Pool, Belleview Pool, and Pike Island Pool all had similar
means (Figure 11a). The lowest standard deviations were 0.0045 from Markland Pool
and 0.0032 from Willow Island Pool. Uniontown Pool had the highest standard
deviation of 0.019148 (Figure 11b).
The lowest mean for jaw length to head length was 0.153 from Markland Pool.
Uniontown Pool, Newburgh Pool, and R.C Byrd Pool had the highest means. These
mean were respectively 0.222, 0.215, and 0.216. McApline Pool, Greenup Pool, and
Pike Island Pool had similar means (Figure 12a). Markland Pool and Willow Island Pool
had the smallest standard deviation of 0.00194 and 0.00199. Uniontown Pool,
Newburgh Pool, and Greenup Pool had the highest standard deviation. The deviations
were 0.056, 0.051, and 0.052, respectively (Figure 12b).
Markland Pool and Greenup Pool had the lowest mean for jaw length to head
depth. These values were 0.205 and 0.229. The highest means were from Uniontown
Pool, Newburgh Pool, and Cannelton Pool. The values were 0.306, 0.3, and 0.301
(Figure 13a). Willow Island Pool had the lowest standard deviation of 0.0073.
Uniontown Pool had the highest standardization of 0.087. McApline Pool, Markland
Pool, and Greenup Pool had similar deviations (Figure 13b).
The lowest mean for jaw length to gape width was contained in Markland Pool
and McApline Pool. The mean values were 0.492 and 0.549. The highest means were
contained in Uniontown Pool, Newburgh Pool, and Cannelton Pool. These values were
respectively 0.763, 0.751, and 0.789 (Figure 14a). Markland Pool and Willow Island
Pool had the lowest standard deviation of 0.036 and .044. The highest standard
deviations were 0.2409, .02129, and 0.2139 contain in the sites of Uniontown Pool,
Newburgh Pool, and Greenup Pool respectively. McApline Pool, R.C. Byrd Pool,
Belleview Pool, and Pike Island Pool had similar standard deviations (Figure 14b).
Discussion
There are limited studies on the effect of navigational dams on the surrounding
organisms, especially in regard the Ohio River. Other studies have focused on the
Mississippi River or the plankton communities of the Ohio River. As species move up
the food chain they become more sensitive to environmental changes. Previous studies
show that navigational dams do not distress zooplankton communities (Thorp et al.
1994), but have been found to disturb benthic forms of phytoplankton as navigational
dams decrease water velocity, which allows the phytoplankton to fall out of the water

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column. (Wehr and Thorp 1997) Our research has shown that higher order species, like
A. grunniens, are morphologically different between navigational pool sites, while L.
macrochirus is not.
L. macrochirus response
In general, we found that L. macrochirus showed no morphological differences
between navigational dam sites, perhaps because the sample size was low. Additional
L. macrochirus would need to be measured to improve statistical power. One possible
reason why no morphological differences were found is because L. macrochirus relies
on the littoral zone of the river for surface insects (Snow et al. 1960). The littoral zone
might have similar characteristics between the alluviated valley and glaciated valley.
Another possibility is that the L. macrochirus is not competing with other species. When
L. cyanellus and L. macrochirus cohabitate, L. cyanellus exhibits a higher survivorship,
growth rate, and greater amount of food contain in the stomach compare to L.
macrochirus (Werner and Hall 1977). Competition in the littoral zone could be low in
both valleys, resulting in similar morphology between sites. If competition was high in
either one of the sites, there would be a difference in morphology. If interspecies
competition was high in both sites, one would expect there to be similar morphology.
A. grunniens response
The results have shown that there is measurable difference in the A grunniens
population. Individuals habiting the McApline navigational pool (glaciated valley) were
morphologically different compared to individuals habiting Newburgh navigational pool
(alluviated valley), Uniontown navigational pool (alluviated valley), and R.C. Byrd Pool
(upper Ohio River alluvial valley). The principal mouth morphological measurement
influencing these differences is jaw length. Specifically, McApline navigational pool had
smaller jaw lengths and less of variety between individuals compare to rest of the
navigational pools.
Significant morphological measurement
Jaw length is an important factor that helps determine which trophic position and
prey size the fish will utilize, usually reducing competition between individuals. Jaw
lengths between life stages are different so young adults do not compete for all the
same food (Sabatés and Saiz 2000). Essentially, fish with small jaw lengths will select
small prey while fish with longer jaw lengths will select bigger prey (Lukoschek and
McCormick 2001). This applies to most species, especially top predators like A.
grunniens. Individuals inhabiting the glacial valley are probably eating smaller prey than
those in alluvial valleys, where the jaw length standardization mean is greater.
Individuals in the McApline navigational pool are probably feeding on cladocerans,
copepods, small fish and small mollusks, while individuals in the alluvial valleys are

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feeding on bigger fish, mollusks, and crayfish (Wallus and Simon 2006). This would
also indicate the glaciated valley and the alluvial valley have different size prey.
Habitat Differences
Alluvial valleys and glaciated valleys have very different characteristics. Alluvial
valleys have vast floodplains; glaciated valleys have constricted floodplains. It is
probable that morphology is being driven by the availability of terrestrial organisms. A.
grunniens in the alluvial valley are relying on the annual flooding cycle to utilize an area
that has an abundant source of food and nutrients (Junk et. al 1989). A. grunniens
relies on insects and even plant matter for its diet. Insects seem to be a good source of
nutrients for A. grunniens during development (Daiber 1952). The floodplain would be a
rich source of terrestrial insects during flood season. It is likely that A. grunniens living
in Uniontown navigational pool, R.C. Byrd navigational pool, and Newburgh navigational
pool have larger jaw lengths than individuals in the McApline navigational pool because
they are developing correctly and have access to large terrestrial insects. Conversely,
A. grunniens living in McApline Pool may not receive enough insects to develop
correctly, since the floodplain constriction limits diet to smaller insects, cladocerans and
copepods, resulting in a smaller average jaw length.
RCC was not tested as an alternative to the FPC because the stream order was
the same throughout the river. In previous studies where stable isotopes were
examined, the flood pulse had little influence over dissolved organic matter in the river
and most nutrients came from production in the river, but the flood plain and backwaters
were an important factor for fish, especially juveniles, to use as a safe refuge and an
alternate food source (Thorp et al. 1998).
Competition effects
In addition to food source, competition for food could be driving morphological
changes. It is important to note that community data were not examined; only the
collection data were examined. The standardization of the McApline navigational pool
was smaller compared to the Uniontown Pool, Newburgh Pool, and R.C. Byrd Pool. A
larger standard deviation would indicate that individuals are more diverse in relation to
jaw length. McApline is more tightly clustered than the rest of the navigational pools,
indicating that individuals in McApline Pool have similar in jaw length. The reason
McApline Pool individuals are less diverse is most likely due to a high level of
competition.
According to IRC, when water in the floodplain is at low velocity, biota, like
insects and plankton, are abundant and diverse because they are not being washed
downstream, reducing overall competition. In contrast, in areas where water velocity is
high there is less diversity in plankton and insect population resulting in increased

13. 13
competition for food in the ecosystem (Schiemer et al, 2001). Most likely, competition in
the McApline Pool has increased because there is less diversity because the water
velocities in the constricted floodplain are not low enough and food is being washed
downstream. Besides competing for food between individuals, A. grunniens also
competes for food with Morone chrysops (Butler 1965). The combination of these
factors could result in smaller jaw length means and deviations due to the fact that prey
diversity declines and competition increases. Species have to start selecting for smaller
prey and change their niche (Werner and Hall 1974; Werner and Hall 1976). In contrast,
A. grunniens habiting the Newburgh Pool, Uniontown Pool, and R.C. Byrd Pool would
have a diverse array of food available because of the lower water velocities in the
floodplain. Competition between individuals and M. chrysops would be minimal
because of the increase in overall diversity; the food chain lengths would be longer
allowing for more selection of prey and species could feed on traditional niches (Roach
et. al, 2009; Werner and Hall, 1976). This would result in the possible increase in
overall jaw length size and diversity.
Changes in water velocity affect river biota. Mesocosms used to examine effects
of water velocity on zooplankton community density and population growth show that
rotifer populations grow faster in high turbulence tanks, while microcrustaceans fare
better in lower turbulence tanks. This could predict where certain zooplankton are likely
to be found along the Ohio River: Microcrustaceans would occur in water near the dam,
and rotifers would occur further from the dam (Sluss et al. 2008).
Further Research
Future research needs to be conducted to interpret differences between
individuals at different navigational sites. Stable isotopes and gut content analysis
would help to better understand what A. grunniens and L. macrochirus feed upon. An
increase in sample size, study sites, and species would help to statistically verify
differences between sites and the differences between the glaciated valley and
alluviated valleys. An increase in sample size would indicate if dams are having a
noticeable effect on larger order organism inhabiting the Ohio River. Genetic studies
could also be conducted to assist in the verification of differences between study sites.
Separating individuals by age class could also help confirm differences between
navigational pool sites. The findings from this study and future studies along the Ohio
River could be adapted to other large rivers that contain navigational dams.
Acknowledgements
This study would not have been possible without the contributions of Dr. Herman
Mays and the Cincinnati Museum of Natural History’s loan of its ichthyology collection. I
would also like to thank Thomas Moore College for allowing me to have access to their

14. 14
ichthyology collection. Special thanks to Dr. Tara Trammell of the University of
Louisville for helping with data analysis through PC-ORD. I am grateful to Dr. Tamara
Sluss, my advisor, for her constant support and guidance throughout this study. This
study was supported by Dr. Kazi Javed, head of the Master's in Environmental Studies
program at Kentucky State University. This study was supported by a grant from the
Kentucky Water Resource Research Institute. I would like to thank Charles Weibel and
Kentucky State University Aquaculture and Aquatic Sciences for providing matching
funds.
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17. 17
Table 1. Navigational pool where A. grunniens was obtained.
Table 2. Navigational pools where L.macrochirus was obtained.
Navigational Pool Name River Kilometer
Pike Island 132 and 134
Willow Island 269
Greenup 546
Markland 853
Newburgh 1162
Uniontown 1420
Table 3. Individual percentvariance and cumulative percentvariance in the data for L. macrochirus for 10 different
principle componentanalysis.
PCA Eigenvalue
Percent of
Variance
Cumulative
Percent of
Variance Eigenvalue
1 7.887 39.434 39.434 3.598
2 5.101 25.504 64.938 2.598
3 2.894 14.472 79.41 2.098
4 1.886 9.43 88.84 1.764
5 0.749 3.744 92.584 1.514
6 0.553 2.764 95.348 1.314
7 0.46 2.3 97.648 1.148
8 0.229 1.147 98.795 1.005
9 0.128 0.638 99.432 0.88
10 0.058 0.29 99.723 0.769
Navigational Pool Name River Kilometer
Pike Island 132
Willow Island 256
Belleview 270
R.C Byrd 390
Greenup 917
Markland 726 and 729
McApline 917
Cannelton 1203
Newburgh 1623
Uniontown 1355 and 1420

18. 18
Table 4. Pearson correlation coefficients between mouth morphologystandardization and principal components in a
PCA of 6 navigational pool sites for L. macrochirus.Significantcorrelations using Bonferroni-corrected probabilities
are shown in bold text.
Standardization PCA 1 PCA 2 PCA 3
Jaw length : mass 0.421 0.2011 0.7745
Jaw length : maximum standard length 0.94 0.2213 -0.095
Jaw length : fork length 0.9487 0.2412 -0.11
Jaw length : maximum total length 0.9484 0.246 -0.129
Jaw length : body depth 0.9463 0.1883 0.1045
Jaw length : head length 0.2188 0.1929 0.4038
Jaw length : eye diameter 0.7323 0.2943 -0.503
Jaw length : snoutlength 0.7522 -0.078 -0.405
Jaw length : head depth 0.9025 0.1722 0.0726
Jaw length : gape width of the mouth 0.9455 -0.309 -0.066
Gape width of the mouth : mass 0.0811 0.2727 0.8659
Gape width of the mouth : maximum standard length -0.181 0.9029 -0.073
Gape width of the mouth : fork length -0.184 0.9424 -0.129
Gape width of the mouth : maximum total length -0.196 0.9438 -0.143
Gape width of the mouth : body depth 0.0331 0.8274 0.3108
Gape width of the mouth : head length 0.0467 0.2511 0.4133
Gape width of the mouth : eye diameter -0.226 0.6621 -0.569
Gape width of the mouth : snoutlength -0.481 0.4101 -0.453
Gape width of the mouth : head depth 0.117 0.7033 0.2506
Gape width of the mouth : jaw length -0.928 0.291 0.073

19. 19
Table 5. Individual percentvariance and cumulative percentvariance in the data for A. grunniens for 10 different
principle componentanalysis.
PCA Eigenvalue
Percent of
Variance
Cumulative
Percent of
Variance Eigenvalue
1 7.72 38.602 38.602 3.598
2 4.629 23.144 61.746 2.598
3 2.003 10.014 71.76 2.098
4 1.855 9.275 81.035 1.764
5 1.783 8.917 89.952 1.514
6 1.065 5.325 95.277 1.314
7 0.429 2.147 97.424 1.148
8 0.291 1.455 98.88 1.005
9 0.076 0.379 99.258 0.88
10 0.042 0.212 99.471 0.769

20. 20
Table 6. Pearson correlation coefficients between mouth morphologystandardization and principal components in a
PCA of 6 navigational pool sites for A. grunniens.Significantcorrelations using Bonferroni-corrected probabilities are
shown in bold text.
Eigenvector
Standardizations 1 2 3
Jaw length : mass 0.5975 -0.1438 -0.3402
Jaw length : maximum standard length 0.9277 -0.3258 0.0133
Jaw length : fork length 0.93 -0.3199 0.0083
Jaw length : maximum total length 0.9282 -0.3227 0.0434
Jaw length : body depth 0.208 -0.2252 0.5849
Jaw length : head length 0.872 -0.2841 0.1284
Jaw length : eye diameter 0.2274 -0.4245 -0.5948
Jaw length : snoutlength 0.5732 -0.0835 0.3611
Jaw length : head depth 0.8395 -0.3574 -0.0434
Jaw length : gape width of the mouth 0.9725 0.1508 -0.0363
Gape width of the mouth : mass 0.2546 -0.2056 -0.3511
Gape width of the mouth : maximum
standard length -0.169 -0.908 0.0568
Gape width of the mouth : fork length -0.1892 -0.9057 0.0417
Gape width of the mouth : maximum total
length -0.2398 -0.8935 0.1132
Gape width of the mouth : body depth 0.0576 -0.2594 0.586
Gape width of the mouth : head length -0.47 -0.7086 0.1584
Gape width of the mouth : eye diameter -0.2172 -0.3898 -0.6074
Gape width of the mouth : snoutlength -0.6066 -0.2552 0.35
Gape width of the mouth : head depth -0.4669 -0.7143 -0.1741
Gape width of the mouth : jaw length -0.9474 -0.2107 -0.0877

21. 21
Figure 1. Types of morphological measurements calculated bySpot Advance.
Figure 2. Types of morphological measurements calculated bySpot Advance.

22. 22
Figure 3. The lastmorphological measurements calculated bySpot Advance.
Figure 4. Navigational pools where individuals were collected.

23. 23
Figure 5. Mean mass,maximum total length,head length,jaw length,and gape width of the mouth for all individuals
of Aplodinotus grunniens.
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
5.000
5.500
6.000
Mass (g) Maxmium Total
Length (cm)
Head Length (cm) Jaw Length (cm) Gap Width of the
Mouth (cm)
Mean(g,cm)+S.E.
Morphological Measurements

24. 24
Figure 6.Mean mass,maximum total length,head length,jaw length,and gape width of the mouth for all individuals
of Lepomis macrochirus.
0.000
0.500
1.000
1.500
2.000
2.500
3.000
3.500
4.000
4.500
5.000
5.500
6.000
6.500
7.000
7.500
8.000
8.500
9.000
9.500
Mass (g) Maxmium Total
Length (cm)
Head Length (cm) Jaw Length (cm) Gap Width of the
Mouth (cm)
Mean(g,cm)+S.E.
Morphological Measurements

25. 25
Figure 7. Principle componentone vs. two (a) and one vs. three (b) for six navigational sites.Bonferroni-corrected
probabilities were insignificant. Pike Island Pool,Willow Island Pool,and Greenup Pool are located in the upper Ohio
River valley. Markland Pool is located in the glaciated valley, Newburgh and Uniontown Pool are located in the
alluviated valley.
a
b

26. 26
Figure 8. Principle componentone vs. two (a) and one vs. three (b) for ten navigational sites.Bonferroni-corrected
probabilities for “a” showed thatp-value < 0.0001. A Bondferroni-corrected probabilityfor “b” was insignificant.Pike
Island Pool,Willow Island Pool,Belleview pool, R.C Byrd Pool,and Greenup Pool are located in the upper Ohio River
valley. Markland Pool and McApline Pool are contained in the lower Ohio River glaciated valley. Cannelton Pool is
enclosed in the constricted valley, Newburgh and Uniontown Pool are located in the lower Ohio River alluviated
valley.
a
b

27. 27
Figure 9. Mean jaw length to maximum standard length of A. grunniens in pools in the Ohio River (a). Standard
Deviation for jaw length to maximum standard length of A. grunniens in pools in the Ohio River (b).
0.000
0.010
0.020
0.030
0.040
0.050
0.060
0.070
0.080
0.090
Mean(dimensionless)+S.E.
Navigational Pool Name
0
0.005
0.01
0.015
0.02
0.025
0.03
StandardDeviation(dimensionless)
Navigational Pool Name
Only one sample
individual
b
a

28. 28
Figure 10. Mean jaw length to fork length of A. grunniens in pools in the Ohio River (a). Standard Deviation for jaw
length to fork length of A. grunniens in pools in the Ohio River (b).
0.000
0.010
0.020
0.030
0.040
0.050
0.060
0.070
0.080
Mean(dimensionless)+S.E.
Navigational Pool Name
0
0.005
0.01
0.015
0.02
0.025
StandardDeviation(dimensionless)
Navigational Pool Name
b
a

29. 29
Figure 11. Mean jaw length to maximum total length of A. grunniens in pools in the Ohio River (a). Standard
Deviation for jaw length to maximum total length of A. grunniens in pools in the Ohio River (b).
0.000
0.010
0.020
0.030
0.040
0.050
0.060
0.070
Mean(dimensionless)+S.E.
Navigational Pool Name
0
0.005
0.01
0.015
0.02
0.025
StandardDeviation(dimensionless)
Navigational Pool Name
b
a

30. 30
Figure 12. Mean jaw length to head length of A. grunniens in pools in the Ohio River (a). Standard Deviation for jaw
length to head length of A. grunniens in pools in the Ohio River (b).
0.000
0.050
0.100
0.150
0.200
0.250
Mean(dimensionless)+S.E.
Navigational Pool Name
0
0.01
0.02
0.03
0.04
0.05
0.06
StandardDeviation(dimensionless)
Navigational Pool Name
b
a

31. 31
Figure 13. Mean jaw length to head depth of A. grunniens in pools in the Ohio River (a). Standard Deviation for jaw
length to head depth of A. grunniens in pools in the Ohio River (b).
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
Mean(dimensionless)+S.E.
Navigational Pool Name
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.1
StandardDeviation(dimensionless)
Navigational Pool Name
b
a

32. 32
Figure 14. Mean jaw length to gape width of the mouth of A. grunniens in pools in the Ohio River (a). Standard
Deviation for jaw length to gape width of the mouth of A. grunniens in pools in the Ohio River (b).
0.000
0.050
0.100
0.150
0.200
0.250
0.300
0.350
Mean(dimensionless)+S.E.
Navigational Pool Name
0
0.05
0.1
0.15
0.2
0.25
0.3
StandardDeviation(dimensionless)
Navigational Pool Name
b
a