1. Figure 2. Principle component one vs. two 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 alluvial
valley.
-10
-8
-6
-4
-2
0
2
4
6
-8 -6 -4 -2 0 2 4 6 8 10
PCA2(dimensionless)
PCA 1 (dimensionless)
Aplodinotus grunniens Mouth Ratios: PCA 1 vs. PCA 2
Pike Island pool
Willow Island pool
Belleview pool
R.C. Byrd pool
Greenup pool
Markland pool
McApline pool
Cannelton pool
Newburgh pool
Uniontown pool
Figure 3. Principle component one vs. two ten navigational sites.
Bonferroni-corrected probabilities showed that p-value < 0.0001.
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 alluvial valley.
THE EFFECT OF POOL GEOMORPHOLOGY ON FEEDING MORPHOLOGY OF APLODINOTUS
GRUNNIENS AND LEPOMIS MACROCHIRUS IN THE OHIO RIVER, USA.
Adam Gerughty, Division of Environmental Studies and Sustainable Systems , Kentucky State University 400 East Main Street, Frankfort, KY 40601 USA
Dr. Tamara Sluss, Division of Mathematics and Sciences, Kentucky State University 400 East Main Street, Frankfort, KY 40601 USA
Methods
•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
•Then preserved in a solution of 95% ethanol.
•The pictures were captured with a Nikon D90 digital camera 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)
•Each picture was then uploaded into Spot Advance version 4.7 imaging software (Diagnostic Instruments
Inc.).
•11 morphological measurements were recorded.
―Mass
―Maximum Standard Length
―Fork Length
―Maximum Total Length
―Body Depth
―Gape Width of the Mouth
•20 different ratios were created for standardization between individuals.
•The jaw length and gape width of the mouth were standardized.
•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.
•PCA was preformed using PC-ORD v 4.25.
•Pearson correlations between mouth standardizations and principle components scores for each
navigational pool were used to understand the driving standardization in the plots.
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.
Discussion
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 competition in the habitats are at minimal
(Werner and Hall 1977).
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 (alluvial valley),
Uniontown navigational pool (alluvial valley), and R.C. Byrd Pool (upper Ohio River alluvial valley).
This could indicate there is a difference in habitat and availability of prey. The principal mouth
morphological measurement influencing these differences is jaw length.
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).
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).
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 alluvial valleys.
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 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.
Introduction
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 lower river is further broken down into three
geological sections.
Ohio River Subdivision Valley Floodplain
Upper Ohio (alluvial valley) High valley walls with wide Channel Vast floodplain
Glaciated Valley Narrow Channel with steep banks Narrow limited floodplain
Constricted Valley Deep valley walls with narrow channel Floodplain almost nonexistent
alluvial Valley Extensive bottomlands Vast floodplain
Aplodinotus grunniens
•Habitat: Open warm waters with a muddy benthic
zone
•Food: Young individuals feed primarily on
copepods and cladocerans, while adults feed on
crayfish, fish, and mollusks
•Hunting behaviors: Rely on sight and touch to
feed
Lepomis macrochirus
•Habitat: Prefer warm waters, can be found among
the littoral zone along lakes and rivers
•Food: Young individuals feed on copepods and
cladocerans while adults feed on large insects or the
occasional frog or fish
•Hunting behaviors: Rely on sight to find insects near
the surface
Objective
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.
References
Junk W., Bayley P., and Sparks R. (1989) The Flood Pulse Concept in River-Floodplain System. Canadian Special Publication of
Fisheries and Aquatic Sciences, 106, 110-127.
Lukoschek V. and McCormick M. (2001) Ontogeny of diet changes in a tropical benthic carnivorous fish, Parupeneus barberinus
(Mullidae): relationship between foraging behavior, habitat use, jaw size, and prey selection. Marine Biology, 138, 1099-
1113.
Ray L. (1974) Geomorphology and Quaternary Geology of the Glaciated Ohio River Valley-A Reconnaissance Study. Geological
Survey Professional Paper, 826, 1-75.
Sabatés A. and Saiz E. (2000) Intra- and interspecific variability in prey size and niche breadth of myctophiform fish larvae. Marine
Ecology Progress Series, 201, 261-271
Thorp J. and Mantovani. (2005) Zooplankton of turbid and hydrologically dynamic prairie rivers. Freshwater Biology, 50, 1474-
1491.
Werner R. and Hall D. (1977) Competition and Habitat Shift in two Sunfishes (Centrarchidae). Ecology, 58, 869-876.
Figure 1. Map of the navigational dam sites along the Ohio River. Provided by
the Army Corp. of Engineers
-8
-6
-4
-2
0
2
4
6
-8 -6 -4 -2 0 2 4 6 8
PCA2(dimensionless)
PCA 1 (dimensionless)
Lepomis macrochirus Mouth Ratios: PCA 1 vs. PCA 2
Pike Island pool
Willow Island pool
Greenup pool
Markland pool
Newburgh pool
Uniontown pool
―Eye Diameter
―Jaw Length
―Head Length
―Head Depth
―Snout Length
Standardization L. macrochirus PCA 1 L. macrochirus PCA 2 A. grunniens PCA 1 A. grunniens PCA 2
Jaw length : mass 0.421 0.201 0.5975 -0.14
Jaw length : maximum standard length 0.94 0.221 0.9277 -0.33
Jaw length : fork length 0.9487 0.241 0.93 -0.32
Jaw length : maximum total length 0.9484 0.246 0.9282 -0.32
Jaw length : body depth 0.9463 0.188 0.208 -0.23
Jaw length : head length 0.2188 0.193 0.872 -0.28
Jaw length : eye diameter 0.7323 0.294 0.2274 -0.42
Jaw length : snout length 0.7522 -0.08 0.5732 -0.08
Jaw length : head depth 0.9025 0.172 0.8395 -0.36
Jaw length : gape width of the mouth 0.9455 -0.31 0.9725 0.151
Gape width of the mouth : mass 0.0811 0.273 0.2546 -0.21
Gape width of the mouth : maximum standard length -0.181 0.903 -0.169 -0.91
Gape width of the mouth : fork length -0.184 0.942 -0.189 -0.91
Gape width of the mouth : maximum total length -0.196 0.944 -0.24 -0.89
Gape width of the mouth : body depth 0.0331 0.827 0.0576 -0.26
Gape width of the mouth : head length 0.0467 0.251 -0.47 -0.71
Gape width of the mouth : eye diameter -0.226 0.662 -0.217 -0.39
Gape width of the mouth : snout length -0.481 0.41 -0.607 -0.26
Gape width of the mouth : head depth 0.117 0.703 -0.467 -0.71
Gape width of the mouth : jaw length -0.928 0.291 -0.947 -0.21
Table 1. Pearson correlation coefficients between mouth morphology
standardization and principal components in a PCA of the navigational pool sites for
L. macrochirus and A. grunniens. Significant correlations using Bonferroni-corrected
probabilities are shown in bold text.