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5-2012

The diets of larval and juvenile pallid sturgeon andshovelnose sturgeon (Scaphirhynchus spp.) in theLower Mississippi RiverAudrey HarrisonClemson University, aharri3@clemson.edu

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Recommended CitationHarrison, Audrey, "The diets of larval and juvenile pallid sturgeon and shovelnose sturgeon (Scaphirhynchus spp.) in the LowerMississippi River" (2012). All Theses. 1383.https://tigerprints.clemson.edu/all_theses/1383

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THE DIETS OF LARVAL AND JUVENILE PALLID STURGEON AND SHOVELNOSE STURGEON (SCAPHIRHYNCHUS SPP.)

IN THE LOWER MISSISSIPPI RIVER

A Thesis Presented to

the Graduate School of Clemson University

In Partial Fulfillment of the Requirements for the Degree

Master of Science Entomology

by Audrey Brooke Harrison

May 2012

Accepted by: John C. Morse, Committee Co-Chair Peter H. Adler, Committee Co-Chair

William T. Slack

ii

ABSTRACT

Although North American sturgeon have been the focus of extensive research in

the last several decades, more research is essential to ensure their conservation. The

free-flowing Lower Mississippi River (LMR) is occupied by two sympatric sturgeon, pallid

[Scaphirhynchus albus (Forbes & Richardson)] and shovelnose sturgeon [Scaphirhynchus

platorynchus (Rafinesque)]. These species are considered “endangered” and

“threatened,” respectively. Recent studies have documented the life history of adult

sturgeon in the Mississippi River, but studies focusing on young-of-year and juveniles

are limited because young fish are difficult to collect and identifications are problematic.

Spawning sites in the LMR are unknown and though extensive effort has been put forth

to capture young sturgeon for scientific study, specimens are seldom collected and

rarely in large numbers. This gap in knowledge is substantial because recruitment

success is important for the recovery and survival of both species. This study takes an

ecosystem approach in exploring microhabitat associations of larval and juvenile pallid

and shovelnose sturgeon based on their diets. During systematic sampling (2001-2010)

of the LMR (river kilometer 131.32-1361.18), 75 total specimens (pallid and shovelnose)

were obtained using a 3.05 m modified Missouri trawl. Gut contents were analyzed and

prey items were identified to the most refined taxonomic level possible. By examining

microhabitats and behaviors of sturgeon prey items (mostly benthic

macroinvertebrates), the microhabitat-feeding associations of sturgeon were predicted.

iii

These findings suggest that both species are specific in the type of microhabitat in which

they feed. The majority of prey items (71.8%) of both sturgeon species belong to a single

subgroup of Chironomidae (Harnischia complex) that are predominantly burrow in sand

substrates, typically in shifting sediments of large river systems. Several other sturgeon

prey items also occupy this microhabitat. These data can be paired with collection data

to assess habitat use, availability, and threats, and to make recommendations for

conservation. Also studied was general early life history information related to feeding

of young-of-year sturgeon. Based on this study, I conclude that larval and juvenile pallid

and shovelnose sturgeon have different feeding habits than adults. This study also

provides an updated checklist of invertebrates known to occur in the Mississippi River.

iv

DEDICATION

To my fiancé, family, and friends, who have never stopped encouraging me to

pursue the things in which my passions lie, thank you all for supporting my endeavor to

give a voice to the things that cannot speak for themselves. May I always strive to

defend the wilderness.

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ACKNOWLEDGEMENTS

First, I would like to thank Dr. Bill P. Stark (Mississippi College), for providing me

the opportunity and instruction to rekindle my love of insects and become a scientist,

and for being an exemplary human being in all aspects.

I would like to thank my advisory committee, Dr. John Morse (Clemson

University) for being “right next door” and providing guidance and instruction during my

work at Clemson, Dr. Peter Adler (Clemson University) for teaching me to think by

redirecting my questions, and Dr. Todd Slack (U.S. Army ERDC-EL), for keeping me on my

toes in the name of “progress.”

I thank Dr. Jack Killgore (U.S. Army ERDC-EL) for providing me the opportunity to

conduct this research and for being a generous leader. This project was supported by

the Mississippi Valley Division and the New Orleans District of the U.S. Army Corps of

Engineers. I thank the U.S. Army ERDC-EL Fish Ecology Team, Vicksburg, MS, for their

work in the field collecting and processing the sturgeon used in this study and Mr.

Robert Wallus for identifying these sturgeon.

I thank Mr. Will Green (MS Department of Environmental Quality), Mr. Charles

Watson (U.S. Environmental Protection Agency), and Dr. Patrick McCafferty (Purdue

University) for providing assistance with prey item identifications.

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TABLE OF CONTENTS

Page

TITLE PAGE ........................................................................................................................ i ABSTRACT ......................................................................................................................... ii DEDICATION .................................................................................................................... iv ACKNOWLEDGEMENTS .................................................................................................... v LIST OF TABLES .............................................................................................................. viii LIST OF FIGURES .............................................................................................................. ix CHAPTER I. INTRODUCTION .............................................................................................. 1 II. LITERATURE REVIEW ...................................................................................... 5 State of the sturgeon ............................................................................... 5 Life history of Scaphirhynchus spp. .......................................................... 6 The Lower Mississippi River, past and present ........................................ 7 Invertebrates of the Mississippi River ..................................................... 9

III. FEEDING HABITATS OF LARVAL AND JUVENILE PALLID AND SHOVELNOSE STURGEON IN THE LOWER MISSISSIPPI RIVER .................................................................................. 10

Abstract .................................................................................................. 10 Introduction ........................................................................................... 10 Materials and Methods .......................................................................... 12 Results .................................................................................................... 16 Discussion............................................................................................... 25

vii

Table of Contents (Continued)

Page

IV. INTERSPECIFIC DIETARY RELATIONSHIPS BETWEEN PALLID AND SHOVELNOSE STURGEON IN THE LOWER MISSISSIPPI RIVER ..................................................................... 28

Abstract .................................................................................................. 28 Introduction ........................................................................................... 28 Materials and Methods .......................................................................... 30 Results .................................................................................................... 34 Discussion............................................................................................... 38

V. UPDATE TO THE MACROINVERTEBRATE FAUNA OF THE MISSISSIPPI RIVER .................................................................................. 39

Abstract .................................................................................................. 39 Introduction ........................................................................................... 39 Materials and Methods .......................................................................... 41 Results .................................................................................................... 42 Discussion............................................................................................... 43 VI. SYNTHESIS .................................................................................................... 44 APENDICES ............................................................................................................... 46

A: Diets of pallid sturgeon and shovelnose sturgeon reported in previous dietary analyses ................................................... 47

B: Macroinvertebrates occurring in the Mississippi River ............................... 51 C: Life histories of sturgeon prey items ........................................................... 63 LITERATURE CITED ......................................................................................................... 67

viii

LIST OF TABLES Page

Table 3.1 Size ranges and quantities of sturgeon species analyzed ........................... .18

3.2 Percent composition by quantity of prey items ingested by Lower Mississippi River sturgeon .................................................... .23

3.3 Two-way frequencies of non-burrowing prey items x stream hydrograph ................................................................................ 25 4.1 Pairwise comparison of dietary overlap (Pianka’s Overlap Index) ....................................................................................... 34

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LIST OF FIGURES

Page Figure

3.1 Sampling distribution, Lower Mississippi River (river kilometer 131.32-1361.18) ........................................................... 18

3.2 Habits of prey items ingested by all Scaphirhynchus spp. ........................... 19 3.3 Substrate associations of prey items ingested by all Scaphirhynchus spp. ............................................................................... 19 3.4 Substrate associations of prey items ingested by pallid sturgeon. ...................................................................................... 20 3.5 Habits of prey items ingested by pallid sturgeon. ....................................... 20 3.6 Substrate associations of prey items ingested by shovelnose sturgeon. ............................................................................. 21 3.7 Habits of prey items ingested by shovelnose sturgeon. .............................. 21 3.8 Substrate associations of prey items ingested by “undetermined” sturgeon..................................................................... 22 3.9 Habits of prey items ingested by “undetermined” sturgeon. ................................................................................................ 22 4.1 Similarity of prey taxa among sturgeon samples ........................................ 35 4.2 Regression analysis of time period of fish capture x percent total gut weight .............................................................................. 35 4.3 Regression analysis of sturgeon total length (mm) x dietary species richness ......................................................................... 36

1

CHAPTER ONE

INTRODUCTION

Sturgeon (Acipenseriformes: Acipenseridae) worldwide are in peril. According to

the International Union for Conservation of Nature, “sturgeon [are] more critically

endangered than any other group of species,” and 25 out of 29 species are listed as

critically endangered, endangered, or vulnerable for extinction (IUCN 2010). North

America is no exception. Eight out of nine species of sturgeon in the United States are

listed as either threatened or endangered in all or part of their ranges (IUCN 2011).

This study focuses on two sympatric species of sturgeon in the Lower Mississippi

River, the pallid sturgeon [Scaphirhynchus albus (Forbes & Richardson)] and the

shovelnose sturgeon [Scaphirhynchus platorynchus (Rafinesque)]. In 1990, the pallid

sturgeon was listed as an endangered species under the Endangered Species Act of 1973

(Federal Register 1990). The decline of this species was attributed to several human

impacts, including modification of habitat and commercial harvest of the fish (Federal

Register 1990). Recently, contamination was added to the impacts on freshwater

sturgeon, and is thought to cause physiological anomalies in populations including

hermaphroditic and intersexed individuals (Divers et al. 2009). In 1993, a recovery plan

for the pallid sturgeon was issued by the United States Fish and Wildlife Service (1993).

The plan listed recommendations and policy changes that are being implemented

presently and included a projected recovery date of 2040. Included in the list of needs

2

was “information on life history and habitat requirements of all life stages of pallid

sturgeon” (United States Fish and Wildlife Service 1993). This was again listed at the top

of sturgeon recovery priority lists in 2005, 2007, and 2008 (Bergman et al. 2008, CERC

2005, United States Fish and Wildlife Service 2007). In 2010, the shovelnose sturgeon

was listed as threatened under the Similarity-of-Appearance Provisions of the

Endangered Species Act (Federal Register 2010). When working with endangered and

threatened species, all knowledge relating to the ecology, behavior, and life history of

the animal is important and relevant.

Little is known about the spawning behavior and early life histories of these

species, which presents a major problem when it comes to designating critical habitat to

protect them. At present, only three of nine North American sturgeon species have

critical habitat designation (United States Fish and Wildlife Service 2011a). Larval and

juvenile pallid sturgeon and shovelnose sturgeon have been studied in the upper

reaches of the Mississippi River and in the Missouri River, but habitats, diets and early

life histories of the two species have yet to be identified in the lower 1,500 river

kilometers of the Mississippi River (Braaten et al. 2007, Grohs et al. 2009, Wanner et al.

2007). This stretch of the river, which extends from its confluence with the Ohio River to

the Gulf of Mexico, is where the river is deepest and widest, making sampling a

challenge, especially in the benthos, where sturgeon feed (Fendeis 1997, Hoover et al.

2007). Also, because spawning sites and nursery habitats are unknown in this area,

larvae are collected infrequently and typically in low densities.

3

Dietary studies are a useful and applied method of discovering information

about organisms. Feeding habits define organisms—they are the basis for competition,

food webs, and habitat use. Because feeding characterizes an organism, dietary studies

can answer questions concerning the types of microhabitat the organism occupies, the

time the organism most actively feeds, and any changes in diets and feeding habitats as

it grows. Diet studies are also a way to collect faunistic data in habitats that scientists

are unable or unlikely to sample. In this case, sturgeon are useful study animals because

they constantly scour the benthos in search of prey. By looking at what these immature

fish are eating, we can assess possible feeding sites and early life-history information.

Additionally, distributions of prey items (e.g., invertebrates) of the Lower Mississippi

River can be assessed based on fish collection data.

The specific objectives of my research concerning the diets of larval and juvenile

sturgeon in the Lower Mississippi River are

1. To determine the feeding habitats of larval and juvenile pallid sturgeon

and shovelnose sturgeon.

2. To determine the dietary overlap between larval and juvenile pallid

sturgeon and shovelnose sturgeon.

3. To determine changes in feeding rates based on time of day.

4. To determine how diets change with growth.

5. To provide updates to the known invertebrate fauna of the Mississippi

River.

4

The specific hypotheses of my research of the diets of larval and juvenile

sturgeon in the Lower Mississippi river are

1. Feeding habitats of larval and juvenile pallid sturgeon and shovelnose

sturgeon will be predictable based on the habitats of the prey items.

2. Dietary overlap between the two species of sturgeon in the Lower

Mississippi River will be significant.

3. Fish collected in the morning will have increased amounts of gut contents

relative to those fish collected in the afternoon.

4. Species richness of prey items will increase as total length of fish

increases.

5

CHAPTER TWO

LITERATURE REVIEW State of Sturgeon

Sturgeon are one of the oldest living groups of vertebrate animals on the planet

and have long been deemed “living fossils” because of their age—Acipenseriformes date

from at least 200 million years before the present—and the fact that extant sturgeon

are represented in the fossil record from the lower Jurassic geologic period (Birstein

1993, Bemis et al. 1997, Findeis 1997). They are also the most endangered (IUCN 2010).

Two species of sturgeon, the pallid sturgeon and the shovelnose sturgeon (Actiopterygii:

Chondrostei: Acipenseriformes: Acipenseridae: Scaphirhynchus spp.) occupy the free-

flowing Lower Mississippi River, which extends from the confluence of the Ohio River at

Cairo, IL, to its mouth at the Gulf of Mexico (Carlson et al. 1985, Kallemeyn 1983, United

States Fish and Wildlife Service 1993). In 1990, the pallid sturgeon [Scaphirhynchus albus

(Forbes and Richardson 1905)] was listed as an endangered species under the

Endangered Species Act of 1973 by the United States Fish and Wildlife Service (Federal

Register 1990). The decline of this species was attributed to several human impacts

including modification of habitat and commercial harvest of the fish (Federal Register

1990). Two recent additions to the list of impacts on the species are water

contamination and hybridization between the two species (Divers et al. 2009, Tranah et

al. 2004). In 1993, a recovery plan for the pallid sturgeon was issued by the U. S. Fish

and Wildlife Service (1993). The plan listed recommendations and policy changes that

6

are being implemented presently and included a projected recovery date of 2040.

Included was the importance of gaining “information on life history and habitat

requirements of all life stages of pallid sturgeon” (United States Fish and Wildlife Service

1993). In years since, the same recommendations remain, with research related to the

spawning behaviors and early life history at the top of priority lists (Bergman et al. 2008,

CERC 2005). In 2010, the shovelnose sturgeon [Scaphirhynchus platorynchus (Rafinesque

1820)] was listed as threatened under the Similarity-of-Appearance Provisions of the

Endangered Species Act of 1973 (Federal Register 2010). The decision to protect the

more populous, but declining shovelnose sturgeon is based on the morphological

similarity of the two species. These species are not easily distinguishable by an

untrained observer, especially the young-of-year. Pallid sturgeon and shovelnose

sturgeon are typically collected at a ratio between 1:5 and 1:400, respectively,

depending on location (Killgore et al. 2007). Critical habitat has not been designated for

either species in any part of their ranges (United States Fish and Wildlife Service 2011b).

Life History of Scaphirhynchus spp.

When working with endangered and threatened fishes, all knowledge relating to

the ecology, behavior, and life-history requirements of the animal is important and

relevant. The life histories of adult pallid sturgeon and shovelnose sturgeon have been

studied, but unanswered questions regarding spawning behaviors, including where and

what environmental conditions are necessary for successful spawning remain (DeLonay

7

et al. 2007). Freshwater sturgeon are migratory animals and are known to travel

upstream to spawn between the spring equinox and summer solstice (Wildhaber et al.

2007). Female Scaphirhynchus spp. do not reach sexual maturity until ages 6-17 and

spawn every 2-3 years and that males do not reach sexual maturity until ages 4-9

(Colombo et al. 2007, Divers et al. 2009, Keenlyne and Jenkins 1993, Stahl 2008). Pallid

and shovelnose sturgeon at lower latitudes (e.g., Lower Mississippi River) might begin

spawning at an earlier age than those in upper portions of the range (e.g., Upper and

Middle Mississippi and Missouri Rivers) because they are thought to have shorter

lifespans and reach smaller sizes (George et al. in press). Lower Mississippi River pallid

sturgeons might be more highly fecund than those in northern portions of their range

(George et al. in press).

The diets of adult pallid and shovelnose sturgeon vary by species. Adult pallid

sturgeon are primarily piscivorous (but still consume invertebrates), and are thought to

switch to piscivory around age 5 or 6 (Hoover et al. 2007, Grohs et al. 2009). Adult

shovelnose sturgeon remain primarily invertivorous throughout all life stages (Hoover et

al. 2007). The diets larval and juvenile pallid and shovelnose sturgeon in upper portions

of their ranges are much like those of the adult shovelnose sturgeon, and are primarily

composed of aquatic insects and other benthic macroinvertebrates (Braaten et al. 2007,

Grohs et al. 2009, Wanner et al. 2007). Sturgeon are benthic feeders and are well

adapted morphologically (ventral positioning of the mouth, laterally compressed body)

for the benthic lifestyle (Findeis 1997, United States Fish and Wildlife Service 1993). The

8

diets of adult pallid and shovelnose sturgeon throughout their range, juvenile pallid

sturgeon, and larval shovelnose sturgeon in the upper portions of their ranges, as

recorded in the literature, are shown in Appendix A.

Lower Mississippi River, past and present

The Lower Mississippi River is the free-flowing portion of the Mississippi River

extending from the mouth of the Ohio River to the Gulf of Mexico (Baker et al. 1991).

This stretch of river once meandered freely, flooded regularly, and was dominated by

bottomland hardwood forests. Modification of the river began in the 1700s and over the

last 300 years has drastically changed the form and function of the river (ARMP 1994,

Baker et al. 1991). More than 90% of the natural floodplain has been lost, denying fish,

invertebrates, waterfowl, and other wetland animals millions of hectares for foraging,

nesting, and spawning (ARMP 1994). As flooding decreased and human occupation

increased, ancient hardwood forests were converted to vast acreages of agricultural

lands along the fertile Mississippi River Delta. This has resulted in changes in the

sediment load, and the discharge of toxins (i.e., pesticides, herbicides, hormones) into

the river provide further threat to each organism that inhabits “America’s great river”

(Wildhaber et al. 2007). Today, many of the banks of the Lower Mississippi River are

armored with cement to minimize erosion, stone dikes redirect water flow, levees are

built to counter flooding, and cutoffs are excavated at river bends to make navigation

easier (ARMP 1994). The modifications of this river system are profound, making

9

conservation of its fauna a complex issue that is not likely to be resolved unless major

changes are made to the political and economic systems of the United States. The river

at present is made up of several habitat features, including steep banks, revetments,

borrow pits, main channel, lotic sandbars, lentic sandbars, pools, and other slackwater

habitats (Baker et al. 1991).

Invertebrates of the Mississippi River

Near the bottom of the food web lie the invertebrate organisms of the river

system. These organisms are an essential part of the nutrient cycle, which not only

sustain larger predators, but also process the organic material that is deposited into the

Mississippi River and its tributaries every day. The Mississippi has not been extensively

sampled for invertebrates, because of its size, but several surveys of benthic

macroinvertebrates have been conducted in the Mississippi River and those data along

with information concerning trophic relationships, habits, and habitats of aquatic insects

will be used to make habitat predictions for prey items ingested by pallid and

shovelnose sturgeon (Battle et al. 2007, Cummins 1973, Merritt et al. 2008, Payne et al.

1989). A compiled list of invertebrates occurring in the Mississippi River including river

kilometers in which they were collected is included in Appendix B.

10

CHAPTER THREE

FEEDING HABITATS OF LARVAL AND JUVENILE PALLID AND SHOVELNOSE STURGEON IN

THE LOWER MISSISSIPPI RIVER

Abstract

The feeding habitats of larval and juvenile pallid sturgeon [Scaphirhynchus albus

(Forbes and Richardson)] and shovelnose sturgeon [Scaphirhynchus platorynchus

(Rafinesque)] from the Lower Mississippi River were evaluated. A total of 75 specimens

collected between 2001 and 2010 were dissected and gut contents were analyzed. The

microhabitats and habits associated with sturgeon prey items were used to make

predictions about habitat use by larval and juvenile pallid and shovelnose sturgeon.

These findings indicate that young pallid and shovelnose sturgeon are feeding primarily

over sandy benthos, particularly in swift currents where substrates are shifting. The

majority of prey items (71.8%) consumed by both sturgeon species belong to a single

subgroup of Chironomidae (Diptera: Chironominae: Harnischia complex) of which

several genera are known to occupy this specific microhabitat.

Introduction

Pallid sturgeon [Scaphirhynchus albus (Forbes and Richardson)] and shovelnose

sturgeon [Scaphirhynchus platorynchus (Rafinesque)] co-occur in the Lower Mississippi

River, which extends from the mouth of the Ohio River, Cairo, IL, to the Gulf of Mexico

11

(Carlson et al. 1985, Kallemeyn 1983, United States Fish and Wildlife Service 1993). The

U.S. Fish and Wildlife Service listed the pallid sturgeon as an “endangered” species

under the Endangered Species Act in 1990 based on declining populations caused by

habitat modification, overharvest, and hybridization (Federal Register 1990). To further

protect the pallid sturgeon, the U.S. Fish and Wildlife Service listed the shovelnose as

“threatened” under the Similarity-of-Appearance Provisions of the Endangered Species

Act in 2010 (Federal Register 2010). Top research priorities listed in pallid sturgeon

recovery plans include gaining information related to larvae and juveniles and habitat

use and requirements for all life stages (United States Fish and Wildlife Service 1993;

Bergman et al. 2008). Dietary studies of larval, juvenile, and adult pallid and shovelnose

sturgeon have been conducted in the northern portions of their range (e.g., Missouri

River Basin and Upper Mississippi River) (Bock et al. 2011, Braaten et al. 2007, Grohs et

al. 2009, Modde & Schmulbach 1977, Rapp et al. 2011, Sechler et al. 2012, Wanner et al.

2007). Diets of adult sturgeon in the Lower Mississippi River (LMR) have been studied

(Harrison et al. 2011, Hoover et al. 2007), but little is known about the feeding of larvae

and juveniles in this region. This uncertainty is partially due to the limited availability of

larval and juvenile sturgeon specimens, which are seldom collected and rarely in large

numbers. Identification of larval sturgeon further complicates this issue, because

morphological characteristics distinguishing the two species at this stage of

development are not always clear and are sometimes shared (Snyder 2002).

12

To protect these species and ensure successful recruitment of young sturgeon in

the LMR, the early life histories must be investigated and habitat requirements must be

better understood. Dietary studies can be effective in making life-history discoveries and

habitat predictions (Hyslop 1980), and these approaches have been used successfully

with sturgeon species (Mason & Clugston 1993, Keevin et al. 2007, Rapp et al. 2011). To

maximize the success of this methodology, prey items must be identified to the most

refined taxonomic level possible, preferably genus or species, as suggested by Rapp et

al. (2011). Life histories of potential prey taxa can differ significantly among genera and

even species, especially in large families such as the Chironomidae (Diptera) (Bailey et

al. 2001). This study takes an ecosystem approach to learning more about habitat use by

larval and juvenile sturgeon based on their diets. The specific objectives of this study

are to 1) compare dietary components of sampled sturgeon species with compiled lists

of known habitat associations of ingested prey items, and 2) to identify respective

riverine habitats of young river sturgeon based on these associations. By investigating

the habitat requirements, habits, and feeding groups of sturgeon prey items, feeding

habits and microhabitats can be better understood and thus provide more defined

targets for conservation.

Materials and Methods

Sturgeon specimens (Scaphirhynchus spp.) were collected between 2001 and

2010 (February-October) using a 3.05 m modified Missouri trawl with 6.35-mm mesh

13

outside and 25.4-mm mesh inside (Herzog et al. 2009), pulled approximately 1.6 km per

haul along benthic substrates in the Lower Mississippi River (Fig. 1). This approach has

been successful for sampling small sturgeon in rivers of the Mississippi River basin

(Herzog et al. 2005; Hrabik et al. 2007) and the Gulf Coastal plain (Kirk et al. in press).

Larval and juvenile fishes were immediately placed in either 95% ethanol solution or

buffered formalin solution and taken to the U.S. Army Engineer Research and

Development Center (ERDC) in Vicksburg, MS. The following data were collected in the

field at time of collection: river kilometer, latitude, longitude, predominant substrate

type (i.e., sand, gravel, mud, detritus), water temperature, conductivity, pH, dissolved

oxygen, turbidity, depth at start of haul, depth at end of haul, distance from shore at

start of haul, and distance from shore at end of haul. Preserved specimens were

processed in the lab by larval fish taxonomist, Mr. Robert Wallus (e.g., Hogue et al.

1976, Wallus 1986, Wallus & Buchanan 1990, Wallus et al. 1990) and were identified to

species (pallid or shovelnose) based on morphological characteristics outlined by Snyder

(2002) or were categorized tentatively as “undetermined” if species identification was

inconclusive based on shared characteristics between the two species.

During the processing for this particular study, four body-length measurements

(to nearest 0.01 mm) were taken and included total length1 (tip of rostrum to end of

caudal fin), total length2 (tip of rostrum to end of caudal filament when present),

standard length, and fork length. Length and width of mouth (0.01 mm) and length and

width of head (0.001 mm) also were measured. All measurements were taken using a

14

digital Vernier caliper and measuring tape. A blotted dry weight was taken by removing

each specimen from its preservative liquid, blotting the specimen with a dry cloth, and

weighing the specimen (to nearest 0.0001 g), using a Mettler AG 104 balance. To

remove the visceral mass, a mid-ventral I-shaped incision extending from the pectoral

fins to the anus was made using a small scalpel and microscissors, except for fishes too

small (<25 mm) to cut with a blade. In those cases, skin along the venter was pulled

apart using forceps and the visceral mass was removed. Once removed, the visceral

mass was placed on a dry tissue, blotted, and weighed (0.0001 g) using a Mettler AG 104

balance. Gut contents were removed from the stomach and intestines and sorted by

taxon (class and order), using an Olympus SZ61 dissecting microscope. The empty

visceral mass was weighed (0.0001 g) to establish gut-content weight. To eliminate the

effect of fish size on gut contents, the gut content weight was divided by the visceral

mass weight to determine percent of visceral mass constituted by prey items.

Identification of prey items was made to the most-refined taxon possible (usually

genus or species), using appropriate taxonomic keys (Epler 2001; Merritt et al. 2008;

Pennak 1953).Voucher prey specimens were placed in either ethanol or formalin

solution (depending on the preservation medium of the respective fish specimen) in 1.5-

ml snap-cap microtubes and stored at the ERDC in Vicksburg, MS, with their respective

fish specimen. Chironomidae were separated into morphotypes and at least one

representative of each morphotype was cleared in lactic acid, dehydrated in a series of

increasing ethanol concentrations (80%, 90%, and 100%), and mounted in Euparal®

15

mounting medium on glass slides (Epler 2001). A Bausch and Lomb Balplan Illuminator

compound microscope was used to identify slide-mounted specimens. Chironomids

were identified using a key to the larval Chironomidae of North and South Carolina

(Epler 2001). All slide-mounted specimens were stored horizontally in slide cases

alongside respective fish specimens at the ERDC Fish Ecology Lab in Vicksburg, MS.

A taxonomic list of all prey items was compiled. Feeding habitat of sturgeon

specimens was analyzed by researching the microhabitats and habits associated with

each prey item (Appendix C). For all Scaphirhynchus spp. specimens, prey items were

quantified and categorized into one of eight groups based on these microhabitat

associations (sand, clay, silt/sand, detritus, gravel/sand, cosmopolitan, mud, unknown)

and into one of five habits (burrowers, sprawlers, clingers, swimmers, climbers). These

data are represented as percentages in charts generated using Microsoft Office Excel.

Charts representing percentages of each microhabitat and habit for all Scaphirhynchus

spp. were generated using Microsoft Office Excel. This analysis was repeated for pallid

sturgeon, shovelnose sturgeon, and “undetermined” Scaphirhynchus specimens

individually. Two-way frequency tables were used to evaluate the occurrence of non-

burrowing sturgeon prey items in relation to stream hydrographs on the day of fish

collection, one week prior to fish collection, and two weeks before fish collection.

Historic stream hydrographs from the nearest upstream gage were obtained from

www.rivergages.com. Expected values were weighted by frequency of collections on

rising limbs, steady limbs, and falling limbs of the hydrograph.

16

Results

A total of 75 larval and juvenile (17.66-386.50 mm total length1) river sturgeon

were analyzed (Table 1). Three larval sturgeon had completely empty stomachs and

intestines. Diets of both pallid and shovelnose sturgeon were primarily composed of

insects (97.3%) with taxa representing Crustacea, Oligochaeta, Hirudinea, and

Actinopterygii occurring in low numbers. Within the Insecta, the Orders Ephemeroptera,

Diptera, Hemiptera, and Trichoptera were represented by 14 families. Chironomidae

(Diptera) was the most-represented family and constituted 91.7% of the gut contents by

quantity. Within the Chironomidae, the most-represented genera were Chernovskiia,

Robackia, and Cryptochironomus. These and other represented genera (Gillotia,

Paracladopelma, Parachironomus, and Saetheria) are all members of the Harnischia

complex (Chironomidae: Chironomini). Other ingested prey items represented a minor

component of sturgeon diets and constituted only 8.3% composition.

The majority of prey items ingested by all sturgeon were categorized as

burrowers (96.9%) and associated with sandy substrates (83%) (Figs. 2,3). Other

substrates associated with sturgeon prey items include clay, detritus, sand/silt mixture,

and sand with gravel. Prey items that are ubiquitous in these substrates and for which

substrate associations are unknown are termed “cosmopolitan” or “unknown,”

respectively (Figure 1). Prey items ingested by pallid sturgeon (n=20) were mostly

burrowers (96.8%) and associated with sandy substrates (89%) (Figs. 4-5). Shovelnose

17

sturgeon (n=26) also ingested primarily burrowers (96.2%) associated with sandy

substrates (89%) (Figs.6-7). Prey items of undetermined Scaphirhynchus spp. (n=27)

were mostly associated with sand (76%) and burrowers made up the majority of prey

items (98.1%) (Figs. 8-9). Percentages of prey items associated with a mixture of sand

and silt were higher in pallid sturgeon (8%) and undetermined sturgeon (8%) than in

shovelnose sturgeon (2%). Percentages of “cosmopolitan” prey items were higher in

shovelnose sturgeon (7%) and undetermined sturgeon (15%), than in pallid sturgeon

(0%). Two-way frequency analyses of occurrence of non-burrowing prey items as related

to the stream hydrograph on day of fish collection (χ2=1103.04), 1 week prior to fish

collection (χ2=713.17), and 2 weeks prior to fish collection (χ2=319.04) were all

statistically significant (p<0.001), although not all observed prey habits exceeded the

expected values (Table 3).

18

Figure 1. Sampling Distribution, Lower Mississippi River (river kilometer 131.32-1361.18). Black points represent sturgeon collection.

Table 1. Size ranges and quantities of sturgeon species analyzed.

Sturgeon Species Size Range (TL1) Quantity

Shovelnose Sturgeon 17.84-271.5 mm 26 Pallid Sturgeon 17.6-335.5 mm 20 Scaphirhynchus spp. (undetermined)

17.82-195.5 mm 27

19

Figure 2. Habits of prey items ingested by all Scaphirhynchus spp.

Figure 3. Substrate associations of prey items ingested by all Scaphirhynchus spp.

20

Figure 4. Substrate preferences of prey items ingested by pallid sturgeon (Scaphirhynchus albus)

Figure 5. Habits of prey items ingested by pallid sturgeon (Scaphirhynchus albus)

21

Figure 6. Substrate associations of prey items ingested by shovelnose sturgeon (Scaphirhynchus platorynchus)

Figure 7. Habits of prey items ingested by shovelnose sturgeon (Scaphirhynchus platorynchus)

22

Figure 8. Substrate preferences of prey items ingested by undetermined Scaphirhynchus spp.

Figure 9. Habits of prey items ingested by undetermined Scaphirhynchus spp.

23

Table 2. Percent composition by quantity of prey items ingested by Lower Mississippi River sturgeon

Prey Taxa Pal

lid

Sho

veln

ose

Un

det

erm

ined

Sca

ph

irh

ynch

us

spp

.

All

Sca

ph

irh

ych

us

spp

.

Insecta

Ephemeroptera

Caenidae

Brachycercus sp. 0.35 1.10 0.10 0.70

Ephemeridae

Hexagenia sp. 0.35 0.50 5.60 2.00

Heptageniidae 0.35 0 0 0

Leptophlebiidae

Leptophlebia sp. 0 0 0.10 0

Palingeniidae

Pentagenia vittigera (Walsh) 0 0.10 0.20 0.20

Polytimarcyidae

Tortopus puella (Pictet) 0 0.10 0 0.10

Pseudironidae

Pseudiron centralis (McDunnough) 0.70 0.80 0 0.60

Siphlonuridae 0 0 0 0

Ephemeroidea undetermined 6.70 0.10 2.40 1.20

Hemiptera

Corixidae 0 0.10 0 0

Trichoptera

Hydropsychidae

Hydropsyche sp. 0 0.20 0 0.10

Potamyia flava 0 0.10 0.10 0.10

Hydropsychidae undetermined 0.40 0.20 0 0.20

Diptera Ceratopogonidae

Probezzia sp. 0 0.10 0.40 0.20

Chaoboridae

Chaoborus sp. 0 0.10 0 0

Chironomidae

Ablabesmyia sp. 0 0.10 0 0

Chernovskiia sp. 25.80 37.00 15.50 29.70

Chironomus spp. 0 3.20 6.80 4.10

Coelotanypus sp. 0 0.80 1.90 1.10

24

Cricotopus sp. 0 0.10 0 0

Cryptochironomus sp. 11.00 4.80 45.00 17.60

Gillotia sp. 0 0.40 5.60 2.00

Glyptotendipes sp. 0 0.20 0 0.10

Limpiniella sp. 0.35 0.10 0.70 0.30

Lopescladius sp. 0.35 6.40 0.10 4.10

Metriocnemus fuscipes (Meigen) 0 0 0.10 0

Nanocladius sp. 0 0 0 0

Parachirionomus sp. 0 0 0.10 0

Paracladopelma sp. 2.50 0.10 0.40 0.40

Paratendipes basidens Townes 34.30 5.70 0.10 5.80

Polypedilum flavum (Johannsen) 0.70 0.40 0.30 0.40

Polypedilum halterale (Coquillett) grp. 0 0.10 0 0

Polypedilum sp. 0 0.70 1.30 0.80

Robackia claviger (Townes) 1.80 26.20 4.80 18.00

Rheosmittia arcuata Caldwell 1.40 0 2.60 0.90

Saetheria sp. 0.35 6.20 1.10 4.30

Zavrelia sp. 0.35 0 0 0

Chironomini undetermined (pupae) 9.90 0.40 1.90 1.40

Orthocladiinae undetermined 0.35 0 0 0

Tanypodinae 0 0.10 1.10 0.40

Oligochaeta 0 0.40 0 0.20

Hirudinea 0 0 0 0

Ostracoda 0 0.10 0 0.10

Amphipoda

Gammaridae 1.40 2.90 1.30 2.30

Corophiidae 0 0 0 0

Actinopterygii 0.70 0 0 0.10

25

Table 3. Two-way frequencies of non-burrowing prey items x stream hydrograph

Day of Sturgeon Capture

Hydrograph

Habit Rising Limb Steady Falling Limb

Sprawler 31 (1.35) 13 (2.04) 22 (21.90)

Clinger 4 (0.23) 3 (0.34) 4 (3.65)

Swimmer 0 (0.10) 1 (0.160) 4 (1.66)

Climber 7 (1.12) 23 (1.70) 25 (18.25)

Weighted Total 42 (2.80) 40 (4.24) 55 (45.46)

1 Week Prior to Capture

Sprawler 20 (6.26) 28 (1.66) 18 (11.9)

Clinger 6 (1.04) 0 (0.28) 5 (1.98)

Swimmer 4 (0.47) 1 (0.130) 0 (0.90)

Climber 35 (5.22) 8 (1.39) 12 (9.92)

Weighted Total 65 (13) 37 (3.45) 35 (24.7)

2 Weeks Prior to Capture

Sprawler 14 (7.55) 0 (0) 52 (25.32)

Clinger 10 (1.26) 0 (0) 1 (4.22)

Swimmer 2 (0.57) 0 (0) 3 (1.92)

Climber 43 (6.29) 0 (0) 12 (21.10)

Weighted Total 69 (15.66) 0 (0) 68 (52.56)

Observed (Expected)

Discussion

Larval and juvenile pallid and shovelnose sturgeon fed on at least 42 different

prey taxa, primarily Chironomidae in the Harnischia complex (Chironominae:

Chironomini). The Harnischia complex and two other represented genera, Rheosmittia

and Lopescladius are characteristic of the psammophilic community in fast-flowing

water (Cranston & Saether 1986). The majority of prey items ingested by larval and

juvenile sturgeon were categorized as primary inhabitants of sandy substrates in high-

26

current environments, strongly suggesting that young sturgeon are predominantly

feeding in this same microhabitat. This habitat association was also found in a study of

hatchery-reared juvenile pallid sturgeon in the Missouri River and in adult shovelnose

sturgeon in the Platte River (Gerrity 2005, Rapp 2011). Because the majority of sturgeon

prey items are burrowers in sediment, given their small size, functional feeding

morphology, and benthic nature, young sturgeon are probably exploiting the flow

boundary layer to access their interstitial prey (Carroll & Wainwright 2003; Findeis

1997). Non-burrowers, particularly clingers and climbers, were present in higher than

expected quantities in fish that were collected on the rising limb of the stream

hydrograph. These organisms possibly were washed out of their habitats and made

available to foraging sturgeon, which has been documented in adult sturgeon feeding

on cicada nymphs (Harrison et al. 2011). Adult Scaphirhynchus spp. are also benthic

feeders, which is reflected by their diets (Findeis 1997, Hoover et al. 2007, Keevin et al.

2007). Given the nature of the sandy channel habitats, young sturgeon possibly are

feeding over and using sand dunes for station holding and increased swimming

efficiency, as demonstrated in laboratory studies of juvenile pallid sturgeon and adult

pallid and shovelnose sturgeon (Adams et al. 2003, Baker et al. 1997, Hoover et al.

2011). This swift-water, shifting sediment habitat constitutes the majority (~80%) of the

Mississippi River proper, including the main channel and secondary channels, and these

channels are important habitats for large-river fish at various developmental stages

(Galat & Zweimüller 2001, Jack Killgore, pers. comm.). To prevent mortality and ensure

27

successful recruitment of larval and juvenile pallid and shovelnose sturgeon, changes

and disturbances to this habitat should be considered in areas where larval and juvenile

sturgeon are known to occur, especially during and directly following time periods when

sturgeon are thought to spawn.

28

CHAPTER FOUR

INTERSPECIFIC DIETARY RELATIONSHIPS BETWEEN LARVAL AND JUVENILE PALLID AND SHOVELNOSE STURGEON IN THE LOWER MISSISSIPPI RIVER

Abstract

Currently, little is known about the interspecific relationships and early life

histories of sympatrically occurring pallid sturgeon and shovelnose sturgeon in the free-

flowing Lower Mississippi River. Dietary overlap, prey community similarity within

species, and differences in diet composition between species were investigated. Larval

and juvenile sturgeon have a considerable amount of overlap, but also have species-

specific dietary differences. This study also reveals early life-history information (i.e.,

feeding activity peaks and changes in diet with growth) based on the diets of larvae and

juveniles. Young sturgeon appear to feed consistently throughout the day and feed on a

wider variety of prey items as they grow.

Introduction

The pallid sturgeon [Scaphirhynchus albus (Forbes and Richardson 1905)] occurs

in the free-flowing Mississippi River, Atchafalaya River, Missouri River, Platte River, and

Yellowstone River, and is federally listed as an “endangered” species throughout its

entire range (Federal Register 1990, Kallemeyn 1983, Reed and Ewing 1993, United

States Fish and Wildlife Service 1993). Its decline is attributed to habitat modification,

overharvest, contamination, and hybridization with its sister species, Scaphirhynchus

29

platorynchus Rafinesque (1820) (shovelnose sturgeon), which occurs sympatrically in

the Mississippi and Missouri river basins (Keenlyne 1997, United States Fish and Wildlife

Service 1993). Adult pallid and shovelnose sturgeon can be distinguished, but

identification of larvae is problematic (Snyder 2002). This taxonomic challenge

complicates investigations of early life-history requirements of the two species. Adult

pallid and shovelnose sturgeon have dietary differences and feeding associations in the

lower portions of their ranges (i.e., Lower Mississippi River, Atchafalaya River) (Carlson

et al. 1985, Hoover et al. 2007), but little is known about larvae and juveniles in this

same region (USFWS 2007). Adult shovelnose sturgeon are thought to occupy slower

moving water and stream margins, while adult pallid sturgeon are thought to occupy the

main channel (Carlson et al. 1985, Kallemeyn 1983). Adult shovelnose are primarily

invertivorous, and pallid sturgeon are known to consume fish (Carlson et al. 1985, Grohs

et al. 2009, Harrison et al. 2011, Hoover et al. 2007). Also, adult river sturgeon are

thought to have nocturnal and crepuscular activity peaks (Modde & Schmulbach 1977).

The rarity of young sturgeon specimens compounded with their problematic

identification suggests that alternative approaches need to be taken to shed light on the

early life histories of these two species.

This study attempts to gain early life history information for both species based

on their diets. Also of interest are dietary relationships between young-of-year and

juvenile pallid and shovelnose sturgeon. The specific objectives of this study are to (1)

determine the amount of dietary overlap between young-of-year and juvenile pallid and

30

shovelnose sturgeon, and (2) investigate dietary differences of pallid and shovelnose

sturgeon. Understanding these specific features of the early life histories of these

species will provide additional insight necessary to promote the recovery and

conservation of these species.

Materials and Methods

Sturgeon specimens (Scaphirhynchus spp.) were collected between 2001 and

2010 (February-October) during systematic sampling of the Lower Mississippi River,

using a 3.05-m modified Missouri trawl with 6.35-mm mesh outside and 25.4-mm mesh

inside (Herzog et al. 2009), pulled approximately 1.6 km per haul along the benthos. This

sampling equipment and technique is useful for capturing small sturgeon in large river

systems (Herzog et al. 2005, Hrabik et al. 2007, Kirk et al. in press). Sturgeon were

immediately placed in either 95% ethanol solution or buffered formalin solution and

taken to the U.S. Army Engineer Research and Development Center in Vicksburg, MS.

Locality data including river kilometer, latitude, and longitude, and environmental data

including substrate type (i.e., sand, gravel, mud, detritus), water temperature,

conductivity, pH, dissolved oxygen, turbidity, water depths at the start of the haul and

the end of the haul, and distances from shore at the start of haul and the end of the

haul were taken at each collection site. Preserved specimens were identified to species

(pallid or shovelnose) or categorized as “undetermined” if species identification was not

possible, by larval fish taxonomist, Mr. Robert Wallus, (e.g., Hogue et al. 1976, Wallus

31

1986, Wallus & Buchanan 1990, Wallus et al. 1990) using a key to larval sturgeon

(Snyder 2002).

For this study, additional measurements were taken and sturgeon digestive

tracts were dissected (see Chapter 3, pp. 13-15). Gut contents were removed, processed

and prey items were identified to genus or species level when possible. Voucher

specimens were deposited at the U.S. Army Engineer Research and Development

Center, Vicksburg, MS, alongside sturgeon.

Dietary overlap was tested using Pianka’s Overlap Index (Gotelli and Entsminger

2004). Sturgeon were segregated by species (i.e., pallid, shovelnose, undetermined),

and prey taxa were combined across all samples to reflect total consumption (n=4457)

by the respective sturgeon grouping. A pairwise comparison was calculated noting

percent dietary overlap between each species. Values range from 0 (no overlap) to 1

(complete overlap) and overlap is considered “biologically significant” when values are

≥0.60 (Pianka 1976). To test for dietary similarities between samples, a “prey taxa” by

“sample” matrix was constructed. Raw abundance values for prey taxa were square-root

transformed to reduce the influence of dominant prey taxa (Clarke and Gorley 2006)

and no taxa were excluded due to rarity. A resemblance matrix was created by

computing Bray Curtis similarity values for each sample comparison. Analytical

assessments of similarity comparisons were computed with the procedures included in

the PRIMER (Plymouth Routines in Multivariate Ecological Research) version 6.1.12

statistical package (Clarke and Warwick 2001; Clarke and Gorley 2006). A cluster analysis

32

(CLUSTER) based on the hierarchical agglomerative method with the group-average

linkage procedure was computed on the resemblance matrix to graphically illustrate

(dendrogram) the grouping of taxonomically similar diet samples by sturgeon sample

number. These values range from 0% (no similarity) to 100% (identical). Within the

dendrogram, black lines represent statistically significant breaks between nodes.

Conversely, red lines denote statistical non-significance. Sturgeon taxon (pallid=PLS,

shovelnose=SS, “undetermined”=UNDET) was then overlaid on sturgeon sample

number. The SIMPROF option was incorporated to test for significance (α=0.05) of

internal structure (Clarke 1993; Clarke and Warwick 2001). Analysis of similarity

(ANOSIM) was conducted to assess differences in prey taxa assemblages between

sturgeon taxa (pallid, shovelnose, “undetermined”). The test statistic for ANOSIM (R),

ranges from 0 (no difference between groups) and 1 (complete separation of groups)

(Clarke and Warwick 2001). ANOSIM is an analytical approach analogous to a one-way

ANOVA that assesses variability in similarity values within treatments to establish the

strength of differences found between treatments. Similarity percentages (SIMPER)

were calculated on the raw abundance values to determine which prey taxa contributed

to the similarity pattern depicted within sturgeon groupings (i.e., typifying prey taxa) as

well as those prey taxa that contributed to the dissimilarity between groups (i.e.,

discriminating prey taxa). A regression analysis (α=0.05) was used to correlate sturgeon

feeding with time of day, using JMP statistical software (JMP 2012). Specimens were

divided into four groups: 1=early morning (7:00-10:00), 2=late morning (10:01-12:00),

33

3=early afternoon (12:01-14:00), 4=late afternoon (14:01-17:00), based on time of fish

collection, and plotted against percent fullness of sturgeon (gut content weight/ weight

of full visceral mass). In addition, a regression analysis (log-transformed) was used to

correlate dietary richness with fish size (total length). Dietary richness was computed by

enumerating numbers of species present in each sturgeon specimen. This analysis was

repeated with species richness by species (JMP 2012). All regression analyses were

performed using version 9 of JMP statistical software (JMP 2012).

Results

A total of 75 pallid (n=20), shovelnose (n=26), and undetermined (n=27)

sturgeon were examined. Dietary overlap was biologically nonsignificant (<0.60) among

all three sturgeon groupings (Table 1). In the dendrogram of Bray Curtis similarity and

cluster analyses, there is separation in sturgeon species based on prey taxa (Figure 1).

Among the 75 specimens analyzed, twelve statistically significant groupings were

present. Dissimilarity between pallid, shovelnose and “undetermined” sturgeon was

significant (R=0.091, p=0.01). Pairwise tests indicate a significant difference in diet

composition between pallid sturgeon and shovelnose sturgeon (R=0.196, p=0.001) and a

significant difference in diet composition between shovelnose sturgeon and

“undetermined” sturgeon (R=0.086, p=0.01), but diet composition between pallid

sturgeon and “undetermined” sturgeon were not significantly different (R=0.003,

p=36.8) (ANOSIM). In pallid sturgeon, typifying prey taxa were Chironomini pupae,

34

Cryptochironomus sp., early instar Ephemeroidea, Amphipoda, and Rheosmittia arcuata

(SIMPER). Typifying prey taxa in shovelnose sturgeon were Chernovskiia sp.,

Cryptochironomus sp., Robackia sp., Amphipoda, Paratendipes sp., Polypedilum flavum,

Saetheria sp., and Polypedilum sp. Typifying prey taxa in “undetermined” sturgeon were

Cryptochironomus sp., Chironomini pupae, early-instar Ephemeroidea, Chernovskiia sp.,

and Paracladopelma sp. (SIMPER). The average dissimilarity in prey taxa between pallid

sturgeon and shovelnose sturgeon was 93.97% (SIMPER). Average dissimilarity in prey

taxa between shovelnose sturgeon and “undetermined” sturgeon was 93.54%. Average

dissimilarity in prey taxa between pallid sturgeon and “undetermined” sturgeon was

90.08% (SIMPER). Time of fish capture and percent fullness of sturgeon gut were weakly

correlated (r2=0.076, p=0.0244) (Figure 2). There was a positive correlation (r2=0.58,

p<0.0001) between sturgeon size (total length) and dietary species richness (Figure 3).

The relationship between species richness and fish species varied between taxa (pallid:

r2= 0.33, p<0.0066; shovelnose: r2=0.44, p<0.0002; undetermined: r2=0.74, p<0.0001).

Table 1. Pairwise Comparison of Dietary Overlap (Pianka’s Overlap Index)

Species Pallid Shovelnose Undetermined

Pallid --- 0.583 0.421

Shovelnose

--- 0.416

Undetermined

---

35

Figure 1. Similarity of prey taxa among sturgeon samples.

Figure 2. Regression analysis of time period of capture by percent total gut weight (r2=0.076).

Time Period

1=early morning (n=5)

2=late morning (n=35)

3=early afternoon (n=18)

4=late afternoon (n=17)

36

Figure 3. Regression analysis of sturgeon total length (mm) by dietary species richness (r2=0.58).

Discussion

Although pallid and shovelnose sturgeon occupy the same macrohabitats, a

significant amount of resource partitioning occurs between the species in early life

stages. Dietary differences between pallid and shovelnose sturgeon are well

documented for adults (Carlson et al. 1985, Gerrity 2005, Grohs et al. 2009, Hoover et

al. 2007), and niche partitioning between the two species is present in early life stages

as well. These analyses (i.e., Bray Curtis similarity, cluster analyses, ANOSIM, SIMPER)

suggest that a species-specific dietary component exists in larval and juvenile sturgeon,

as differences in diet composition between species were statistically significant.

Groupings in the Bray Curtis similarity matrix could also be related to seasonality or

37

sturgeon size. No significant differences between diet composition of pallid sturgeon

and undetermined sturgeon were found, which implies that undetermined specimens

may actually be pallid sturgeon. These fish could be re-examined by larval fish

taxonomists to locate additional distinguishing characteristics. A better understanding

of distinguishing morphological characteristics would be beneficial to scientists

monitoring young-of-year and juvenile populations of each species.

Although adult sturgeon are thought to have peak periods of feeding activity at

crepuscular periods (Modde & Schmulbach 1977), larvae and juveniles feed throughout

the day. Continual feeding could be necessary for rapidly growing larvae and juveniles to

meet nutritional requirements. This observation is limited, however, by the absence of

young sturgeon collected at night.

Young sturgeon feed on a wider variety of prey items (i.e., more species) as they

grow. These findings are in line with observations of age-0 sturgeon from the Middle

Mississippi River and Missouri River (Braaten et al. 2007, Sechler et al. 2012). These

changes could be related to seasonal prey availability, reduced gape limitation, or the

movement of larger, more mobile young-of-year and juvenile sturgeon into different

habitats. Previous diet studies of adult pallid and shovelnose sturgeon show higher

percentages of Trichoptera and Ephemeroptera in winter and spring months, but in the

current study these groups constituted a minimal percentage of prey items and the

trend was not observed (Hoover et al. 2007, Modde & Schmulbach 1977). Prey species

richness among sturgeon species (pallid, shovelnose, “undetermined”) differed between

38

taxa. This observation was limited, however, by the lack of specimens of each species

across a continual size range. Future investigations of early life histories of these

sturgeon are needed and should focus on seasonal and size-based dietary changes. This

information is necessary for accurate monitoring and successful recovery of pallid

sturgeon.

39

CHAPTER FIVE

UPDATE TO THE MACROINVERTEBRATE FAUNA OF THE MISSISSIPPI RIVER

Abstract

The invertebrate fauna of the Mississippi River is compiled from published

material (205 taxa) and records of 10 new taxa obtained in a dietary study of sturgeon in

the Lower Mississippi River. The previously undocumented taxa are Leptophlebia sp.

(Ephemeroptera: Leptophlebiidae), Pseudiron centralis McDunnough (Ephemeroptera:

Pseudironidae), Gillotia sp. (Diptera: Chironomidae), Lipiniella sp. (Diptera:

Chironomidae), Metriocnemus fuscipes (Meigen) (Diptera: Chironomidae),

Parachironomus sp. (Diptera: Chironomidae), Paratendipes basidens Townes (Diptera:

Chironomidae), Polypedilum flavum (Johannsen) (Diptera: Chironomidae), Saetheria sp.

(Diptera: Chironomidae), and Zavrelia sp. (Diptera: Chironomidae).

Introduction

Although much attention has been given to the fish and other vertebrates of

North America’s largest river system, the Mississippi, the invertebrate fauna has been

poorly documented and existing records are patchy. This faunistic uncertainty is at least

partially due to the length (3,766 km) and breadth of the Mississippi River, which

extends from Lake Itasca in western Minnesota to the Gulf of Mexico (Kammerer 1990).

Some macrohabitats have been sampled extensively, but others, such as the main

40

channel, remain largely unknown. As a result, no clarity exists regarding the true fauna

of the Mississippi River, especially the invertebrates. New approaches and techniques

should be employed to understand better the fauna of this system and its role in

bioenergetics, nutrient cycling, and water quality.

My study takes an ecosystem approach to documenting the extant fauna of the

free-flowing Lower Mississippi River, which stretches from the mouth of the Ohio River

to the Gulf of Mexico (Baker et al. 1991). This portion of the river has been modified

drastically from its natural state. Modification for ease in navigation began in the 1700s

and over the last 300 years has significantly changed the river’s form and function

(ARMP 1994, Baker et al. 1991). The natural floodplain has been reduced significantly

and ancient hardwood forests have been replaced with row-crop agriculture. These

alterations have changed the sediment load and have increased the amounts of toxins

entering the river (Wildhaber et al. 2007). The Lower Mississippi River is now lined with

cement, has stone dikes and levees, and has been shortened by many miles (ARMP

1994). Also, because of organic loading and input of toxins, the Gulf of Mexico at the

mouth of the Mississippi River annually becomes a hypoxic dead zone (Rabalais et al.

2002).

The macroinvertebrate community of the Lower Mississippi River was explored

through examination of the gut contents of two benthic fish, pallid sturgeon

[Scaphirhynchus albus (Forbes & Richardson, 1905)] and shovelnose sturgeon

[Scaphirhynchus platorynchus (Rafinesque, 1820)]. Sturgeons scour the benthos in

41

search of food, and their preference for aquatic invertebrates makes them ideal study

animals for investigating invertebrates in big rivers. Museum specimens of fish are

useful when looking at distributional records of invertebrates through history.

Specimens can be dissected without harm to the integrity of the specimen, and

ichthyologists commonly use formalin or ethanol (EtOH) as a preservative, which also

preserves invertebrate prey items in fish stomachs. Studying fish diets can be a

productive, applied approach to investigating river fauna, because fish are sampling as

they meet their daily nutrient requirements.

Materials and Methods

A total of 75 young-of-year sturgeon specimens (Scaphirhynchus spp.) captured

in the Lower Mississippi River (RKM 131.32-1361.18) in 2001-2010 were studied. For

most specimens, a midventral longitudinal incision extending from the pectoral fins to

the anus was made using a small scalpel and microscissors. For fishes too small (<25

mm) to cut with blades, skin along the venter was pulled apart with forceps, and the

visceral mass was removed. Gut contents were removed from the stomach and

intestines and sorted by taxon (class and order) under an Olympus SZ61 dissecting

microscope. When possible, prey items were identified to genera and species with

appropriate taxonomic keys (Epler 2001, Merritt et al. 2008, Pennak 1953). Voucher

macroinvertebrates were placed in either ethanol or formalin solution (depending on

the preservation method of the respective source fish) in 1.5-ml snap-cap microtubes

42

and stored at the U.S. Army Engineer Research and Development Center (ERDC) in

Vicksburg, MS, with their respective fish. Chironomidae were separated into

morphotypes and at least one representative of each morphotype was cleared in lactic

acid, dehydrated in a series of increasing ethanol concentrations (80%, 90%, and 100%),

and mounted on a plain glass slide, using Euparal® mounting medium (Epler 2001).

Under a Bausch and Lomb Balplan Illuminator compound microscope, I identified

specimens with a key to the larval Chironomidae of North and South Carolina (Epler

2001). Slide-mounted specimens were stored horizontally in slide cases alongside

respective fish at the ERDC in Vicksburg, MS. Uncertain identifications were confirmed

by Mr. Will Green (MS Department of Environmental Quality, Mr. Charles Watson (U.S.

Environmental Protection Agency), and Dr. Patrick McCafferty (Purdue University). A

taxonomic list of all prey items was compiled, including collection location of fish (river

kilometer). I followed Turgeon et al. (1998) for current nomenclature on mollusks.

Results

In total, 215 taxa from the Mississippi River were documented. Represented

phyla, subphyla, and classes were Arachnida, Clitellata, Crustacea, Insecta, Mollusca,

Nematoda, Rotifera, Tardigrada, and Turbellaria. The best-represented family of

invertebrates in the Mississippi River, in both the literature and my study, was

Chironomidae (Diptera), which occupy a wide variety of habitats worldwide (Oliver

1971). Appendix B is a list of Mississippi River invertebrates previously recorded in the

43

literature and new records from my study. The previously undocumented taxa are

Leptophlebia sp. (Ephemeroptera: Leptophlebiidae), Pseudiron centralis McDunnough

(Ephemeroptera: Pseudironidae), Gillotia sp. (Diptera: Chironomidae), Lipiniella sp.

(Diptera: Chironomidae), Metriocnemus fuscipes (Meigen) (Diptera: Chironomidae),

Parachironomus sp. (Diptera: Chironomidae), Paratendipes basidens Townes (Diptera:

Chironomidae), Polypedilum flavum (Johannsen) (Diptera: Chironomidae), Saetheria sp.

(Diptera: Chironomidae), and Zavrelia sp. (Diptera: Chironomidae).

Discussion

Freshwater macroinvertebrates are vital to the health and biodiversity of flowing

water systems. These animals are also crucial components of food webs and serve as

prey items for endangered predators such as pallid sturgeon. Among

macroinvertebrates, at least two mussels, Lampsilis higginsii (Lea) and Potamilus capax

(Green) (Bivalvia: Unionidae), occurring in the Mississippi River are federally listed as

endangered, and most other mussels are listed as endangered or threatened in parts of

their ranges by state wildlife agencies (USFWS 2006; IUCN 2011). Several insect species

found in our study are rarely collected by entomologists because they occupy habitats

that are not easily accessible, such as the sandy main channel and steep clay banks.

These organisms include Pseudiron centralis McDunnough, Chernovskiia sp., Saetheria

sp., Gillotia sp., Rheosmittia arcuata Caldwell, Paracladopelma sp., Tortopus puella

(Pictet), and Pentagenia vittigera (Walsh).

44

CHAPTER SIX

SYNTHESIS

My study integrates two fields of study, entomology and ichthyology, to gain

insight into the life histories of two sympatric species of sturgeon in the Lower

Mississippi River. These species, pallid sturgeon (Scaphirhynchus albus) and shovelnose

sturgeon (S. platorynchus) are federally listed as “endangered” and “threatened,”

respectively (Federal Register 1990, Federal Register 2010). Without careful planning

and protection, these species are vulnerable to extinction in parts, if not all, of their

ranges. To protect these fish, life history requirements, especially those of larvae and

juveniles, must be better understood. The survival of these species depends on the

successful recruitment of the young fish.

This study sheds light on the early life histories (i.e., habitat requirements,

feeding patterns, interspecific relationships) of pallid and shovelnose sturgeon, based on

their diets. Because young-of-year sturgeon are primarily insectivorous and much is

known about the habits and habitats of freshwater insects, it is possible to use life-

history information of sturgeon prey items to make inferences about life-history

requirements of the sturgeon themselves. To fully understand feeding dynamics of

sturgeon in all life stages, it is important to understand also the insects that sturgeon do

not usually eat. To accomplish this, the benthic fauna of the Lower Mississippi River

must be extensively sampled.

45

This survey of the invertebrates previously documented from the Mississippi

River serves as a running list of potential prey items and non-prey items of sturgeon in

this region. Future efforts should be made to describe this fauna more accurately.

46

APPENDICES

47

Appendix A

Diets of pallid sturgeon and shovelnose sturgeon

reported in previous dietary analyses

.

Sturgeon Species Life Stage Prey Item Phylum

or Class

Prey Item Order Prey Item Family or Genus Reference

SS, PS Adult Nematoda Hoover et al. 2007, Modde and

Schmulbach 1977

SS Adult Clitellata-

Oligochaeta

Haplotaxida,

unknown

Oligochaeta

Bock et al. 2010, Modde and

Schmulbach 1977, Wanner et al.

2007

PS Adult Mollusca Veneroida Dreissena Hoover et al. 2007

SS Adult Mollusca Veneroida Corbicula, Dreissena,

unknown Sphaeriidae

Bock et al. 2010, Hoover et al.

2007

SS Adult Crustacea-

Branchiura

Wanner et al. 2007

SS Adult Crustacea-

Copepoda

Hoover et al. 2007

PS Adult Crustacea Cladocera Hoover et al. 2007

SS, PS Adult Malacostraca Isopoda Asellus, unknown Isopoda Hoover et al. 2007, Modde and

Schmulbach 1977, Wanner et al.

2007

PS Juvenile Malacostraca Isopoda Wanner et al. 2007

SS, PS Adult Malacostraca Amphipoda Gammaridae Hoover et al. 2007, Modde and

Schmulbach 1977, Wanner et al.

2007

PS Adult Malacostraca Decapoda Macrobrachium ohione Hoover et al. 2007

SS Adult Malacostraca Decapoda Macrobrachium ohione,

Cambaridae

Bock et al. 2010, Hoover et al.

2007

PS Juvenile Malacostraca Decapoda Astacidae Grohs et al. 2009

PS Adult Insecta Ephemeroptera Hexagenia, unknown

Ephemeroptera

Hoover et al. 2007

48

SS Adult Insecta Ephemeroptera Ameletus, Isonychia,

Pseudiron, Parameletus,

Hexagenia, Litobranchia,

Pentagenia, Tortopus,

Ephoron, Brachycercus,

Cercobrachys, Baetidae,

Baetiscidae, Ephemeridae,

Leptophlebiidae,

Metretopodidae, unknown

Ephemeroptera

Bock et al. 2010, Modde and

Schmulbach 1977, Wanner et al.

2007

SS Larva Insecta Ephemeroptera Braaten et al. 2007

PS Juvenile Insecta Ephemeroptera Isonychia, Pseudiron,

Hexagenia, Cercobrachys,

unknown Caenidae,

Polymitarcyidae

Grohs et al. 2009, Wanner et al.

2007

PS Adult Insecta Odonata Anisoptera, unkown

Odonata

Hoover et al. 2007

SS Adult Insecta Odonata Libellula, Gomphus,

Stylurus,Calopterygidae,

Coenagrionidae, unknown

Odonata

Bock et al. 2010, Modde and

Schmulbach 1977, Wanner et al.

2007

PS Juvenile Insecta Odonata Gomphus Wanner et al. 2007

PS Juvenile Insecta Plecoptera Unknown Perlodidae Grohs et al. 2009

SS Adult Insecta Plecoptera Perlidae, unknown

Plecoptera

Bock et al. 2010, Modde and

Schmulbach 1977

PS Adult Insecta Hemiptera Corixidae Hoover et al. 2007

SS Adult Insecta Hemiptera Belostomatidae, Corixidae,

Pleidae

Bock et al. 2010, Hoover et al.

2007, Modde and Schmulbach

1977

SS Adult Insecta Megaloptera Corydalidae Bock et al. 2010

PS Adult Insecta Coleoptera Dytiscidae, Haliplidae,

unknown Coleoptera

Hoover et al. 2007

SS Adult Insecta Coleoptera Dytiscidae, Chrysomelidae,

Elmidae, Haliplidae,

Psephenidae,

Bock et al. 2010, Hoover et al.

2007, Modde and Schmulbach

1977, Wanner et al. 2007

49

Ptilodactylidae, unknown

Coleoptera

PS Juvenile Insecta Coleoptera Wanner et al. 2007

PS Adult Insecta Trichoptera Hydropsychidae, unkown

Trichoptera

Hoover et al. 2007

SS Adult Insecta Trichoptera Hydropsyche, Potamyia

flava, Hydropsychidae,

Psychomyiidae, unknown

Trichoptera

Bock et al. 2010, Modde and

Schmulbach 1977, Wanner et al.

2007

PS Juvenile Insecta Trichoptera Hydropsyche, Potamyia

flava, unknown

Hydropsychidae

Wanner et al. 2007, Grohs et al.

2009

PS Adult Insecta Lepidoptera unknown Lepidoptera Hoover et al. 2007

SS Adult Insecta Lepidoptera Crambidae, Noctuidae Bock et al. 2010

SS Adult Insecta Hymenoptera Formicidae Bock et al. 2010

PS Juvenile Insecta Hymenoptera Formicidae Grohs et al. 2009

PS Adult Insecta Diptera Ceratopogonidae,

Chironomidae, Chaoboridae,

Simuliidae, Stratiomyidae,

unknown Diptera

Hoover et al. 2007

SS Adult Insecta Diptera Ceratopogonidae,

Chironomidae, Chaoboridae,

Simuliidae, Stratiomyidae,

Tipulidae, unknown Diptera

Bock et al. 2010, Hoover et al.

2007, Modde and Schmulbach

1977, Wanner et al. 2007

SS Larva Insecta Diptera Chironomidae,

Ceratopogonidae

Braaten et al. 2007

PS Juvenile Insecta Diptera Chironomidae, Simuliidae,

Ceratopogonidae

Wanner et al. 2007, Grohs et al.

2009

SS Adult Arachnida Araneae,

unknown Aracnid

Bock et al. 2010, Modde and

Schmulbach 1977

SS, PS Adult Arthropoda

unkown

Hoover et al. 2007, Modde and

Schmulbach 1977

PS Adult Actinopterygii Cypriniformes Macrhybopsis aestivalis,

Macrhybopsis storeriana,

unknown Cyprinidae

Hoover et al. 2007

50

PS Juvenile Actinopterygii Cypriniformes Macrhybopsis storeriana,

Notropis atherinoides

Wanner et al. 2007

PS Adult Actinopterygii Clupeiformes Unknown Clupeidae Hoover et al. 2007

PS Adult Actinopterygii Perciformes Aplodinotus grunniens,

unknown perciform

Hoover et al. 2007

SS Adult Actinopterygii Perciformes Etheostoma nigrum Wanner et al. 2007

PS Juvenile Actinopterygii Perciformes Etheostoma nigrum, Grohs et al. 2009, Wanner et al.

2007

PS Adult Actinopterygii Non-Perciform Hoover et al. 2007

PS Juvenile Actinopterygii Siluriformes Ictalurus punctatus Grohs et al. 2009, Wanner et al.

2007

SS Adult Actiopterygii Unknown fish, fish eggs Bock et al. 2010, Wanner et al.

2007

PS Juvenile Actinopterygii Grohs et al. 2009, Wanner et al.

2007

51

Appendix B

The Macroinvertebrate Fauna of the Mississippi River

Phylum/Class/ Subclass/Order

Family/ Subfamily

Genus Species Location (RKM) Source

Insecta/ Parainsecta

Collembola 825.59-828.18 (LMR)

Bingham et al. 1982

Ephemeroptera Ameletidae Ameletus sp. 402.34-1504.74 (LMR)

Aartila et al. 1988

Caenidae *Brachycercus sp. 106-114 (UMR); 131.32-1361.18 (LMR)

Battle et al. 2007

Caenis latipennis Banks 106-114 (UMR) Battle et al. 2007

Caenis sp. 402.34-1504.74 (LMR); 0-1393.69 (UMR); 820.76-828.18 (LMR)

Aartila 1988; Angradi et al. 2009; Payne et al. 1989

Tricorythodes sp. 820.76-828.18 (LMR)

Payne et al. 1989

Baetidae 402.34-1504.74 (LMR); 106-114 (UMR)

Aartila 1988; Battle et al. 2007

Baetis sp. 811.11-910.89 (LMR); 820.76-828.18 (LMR)

Beckett and Pennington 1986; Payne et al. 1989

Pseudocloeon sp. 0-1393.69 (UMR); 820.76-828.18 (LMR)

Angradi et al. 2009; Payne et al. 1989

Ephemerellidae Ephemerella sp. 106-114 (UMR) Battle et al. 2007

Eurylophella sp. 106-114 (UMR) Battle et al. 2007

Ephemeridae *Hexagenia sp. 402.34-1504.74 (LMR); 0-1393.69 (UMR); 106-114 (UMR); 825.59-828.18 (LMR); 1.61-305.78 (MMR) 249.45-1375.99 (LMR); 131.32-1361.18 (LMR)

Aartila 1988; Angradi et al. 2009; Battle et al. 2007; Bingham et al. 1982; Hoover et al. 2007; Jude 1973

Hexagenia limbata (Serville) 811.11-910.89 (LMR)

Beckett and Pennington 1986

Hexagenia bilineata (Say) 811.11-910.89 (LMR)

Beckett and Pennington 1986

*Heptageniidae 0-1393.69 (UMR); 131.32-1361.18 (LMR)

Angradi et al. 2009

Heptagenia flavescens (Walsh) 106-114 (UMR) Battle et al. 2007

Heptagenia grp. 106-114 (UMR); 820.76-828.18 (LMR)

Battle et al. 2007; Payne et al. 1989

Leucrocuta sp. 106-114 (UMR) Battle et al. 2007

Mccaffertium mexicanum integrum (McDunnough)

106-114 (UMR); 315 -1223 (UMR);

Battle et al. 2007; Lewis 1974

52

Mccaffertium terminatum terminatum (Walsh)

106-114 (UMR); 865 (UMR)

Battle et al. 2007; Lewis 1974

Stenacron sp. 820.76-828.18 (LMR)

Payne et al. 1989

Stenonema sp. 0-1393.69 (UMR); 106-114 (UMR); 820.76-828.18 (LMR)

Angradi et al. 2009; Battle et al. 2007; Payne et al. 1989

Isonychiidae Isonychia sp. 106-114 (UMR); 820.76-828.18 (LMR)

Battle et al. 2007; Payne et al. 1989

*Leptophlebiidae Leptophlebia sp. 131.32-1361.18 (LMR)

Neoephemeridae Neoephemera sp. 106-114 (UMR) Battle et al. 2007

Palingeniidae *Pentagenia vittigera (Walsh) 402.34-1504.74 (LMR); 811.11-910.89 (LMR); 131.32-1361.18 (LMR)

Aartila 1988; Beckett and Pennington 1986; Beckett et al. 1983

Polymitarcyidae *Tortopus puella (Pictet) 131.32-1361.18 (LMR); 402.34-1504.74 (LMR); 811.11-910.89 (LMR)

Aartila 1988; Beckett and Pennington 1986

Potamanthidae Anthopotamus sp. 106-114 (UMR) Battle et al. 2007

Potamanthus sp. 820.76-828.18 (LMR)

Payne et al. 1989

Pseudironidae *Pseudiron centralis McDunnough

131.32-1361.18 (LMR)

Odonata Corduliidae Macromia illinoensis georgiana (Selys)

106-114 (UMR) Battle et al. 2007

Neurocordulia sp. 820.76-828.18 (LMR)

Payne et al. 1989

Coenagrionidae 820.76-828.18 (LMR)

Payne et al. 1989

Gomphidae Dromogomphus sp. 106-114 (UMR); 820.76-828.18 (LMR)

Battle et al. 2007; Payne et al. 1989

Gomphus sp. 106-114 (UMR) Battle et al. 2007

Stylurus sp. 106-114 (UMR) Battle et al. 2007

Plecoptera Taeniopterygidae Taeniopteryx sp. 106-114 (UMR) Battle et al. 2007

Perlidae Acroneuria abnormis (Newman)

106-114 (UMR) Battle et al. 2007

Acroneuria evoluta Klapálek 106-114 (UMR) Battle et al. 2007

Attaneuria ruralis (Hagen) 106-114 (UMR) Battle et al. 2007

Neoperla sp. 106-114 (UMR); 820.76-828.18 (LMR)

Battle et al. 2007; Payne et al. 1989

Perlesta sp. 106-114 (UMR); 820.76-828.18 (LMR)

Battle et al. 2007; Payne et al. 1989

Perlodidae Hydroperla fugitans (Needham and Claassen)

106-114 (UMR) Battle et al. 2007

Hydroperla sp. 106-114 (UMR) Battle et al. 2007

Isoperla bilineata (Say) ~764.44 (UMR) Webb and DeWalt 1997

53

Trichoptera Hydropsychidae Cheumatopsyche sp. 106-114 (UMR) Battle et al. 2007

Hydropsyche bidens Ross 106-114 (UMR); 820.76-828.18 (LMR)

Battle et al. 2007; Payne et al. 1989

Hydropsyche orris Ross 402.34-1504.74 (LMR); 106-114 (UMR); 811.11-910.89 (LMR); 820.76-828.18 (LMR)

Aartila 1988; Battle et al. 2007; Beckett and Pennington 1986; Payne et al. 1989

Hydropsyche simulans Ross 106-114 (UMR) Battle et al. 2007

Hydropsyche venularis Banks 106-114 (UMR) Battle et al. 2007

*Hydropsyche sp. 0-1393.69 (UMR); 131.32-1361.18 (LMR); Pool 19 (UMR)

Angradi et al. 2009; Jude 1973

*Potamyia flava (Hagen) 402.34-1504.74 (LMR); 106-114 (UMR); 814.33-910.89 (LMR); 820.76-828.18 (LMR); 131.32-1361.18 (LMR)

Aartila 1988; Battle et al. 2007; Beckett et al. 1983; Payne et al. 1989

Hydroptilidae Neotrichia sp. 402.34-1504.74 (LMR); 820.76-828.18 (LMR)

Aartila 1988; Payne et al. 1989

Hydroptila sp. 0-1393.69 (UMR); 106-114 (UMR)

Angradi et al. 2009; Battle et al. 2007

Leptoceridae 106-114 (UMR) Battle et al. 2007

Ceraclea sp. 820.76-828.18 (LMR)

Payne et al. 1989

Nectopsyche sp. 402.34-1504.74 (LMR)

Aartila 1988

Oecetis sp. Pool 19 (UMR) Jude 1973

Polycentropodidae Cyrnellus fraternus (Banks) 820.76-828.18 (LMR)

Payne et al. 1989

Neureclipsis sp. 106-114 (UMR); 820.76-828.18 (LMR)

Battle et al. 2007; Payne et al. 1989

Coleoptera Elmidae 820.76-828.18 (LMR)

Payne et al. 1989

Stenelmis sp. 106-114 (UMR) Battle et al. 2007

Dytiscidae 1.61-305.78 (MMR) 249.45-1375.99 (LMR)

Hoover et al. 2007

Haliplidae 1.61-305.78 (MMR) 249.45-1375.99 (LMR)

Hoover et al. 2007

Staphylinidae 106-114 (UMR) Battle et al. 2007

Diptera Ceratopogonidae Bezzia sp. 402.34-1504.74 (LMR)

Aartila 1988

Ceratopogon sp. 106-114 (UMR) Battle et al. 2007

Culicoides sp. 106-114 (UMR) Battle et al. 2007

Monohelea sp. 106-114 (UMR) Battle et al. 2007

Palpomyia/Bezzia sp. 402.34-1504.74 (LMR); 106-114 (UMR); 814.33-

Aartila 1988; Battle et al. 2007; Beckett et al. 1983

54

910.89 (LMR)

*Probezzia sp. 106-114 (UMR); 131.32-1361.18 (LMR)

Battle et al. 2007

Chaoboridae *Chaoborus sp. 106-114 (UMR); 825.59-828.18 (LMR); 131.32-1361.18 (LMR)

Battle et al. 2007; Bingham et al. 1982

Chaoborus punctipennis (Say) 402.34-1504.74 (LMR); 811.11-910.89 (LMR)

Aartila 1988; Beckett and Pennington 1986; Beckett et al. 1983

Chironomidae Chironominae

Chernovskiia orbicus (Townes) 402.34-1504.74 (LMR); 811.11-910.89 (LMR)

Aartila 1988; Beckett and Pennington 1986; Beckett et al. 1983

*Chernovskiia sp. 131.32-1361.18 (LMR)

*Chironomus sp. 106-114 (UMR); 814.33-910.89 (LMR); 0-1393.69 (UMR); 820.76-828.18 (LMR); 131.32-1361.18 (LMR)

Battle et al. 2007; Beckett et al. 1983; Canfield et al. 1998; Payne et al. 1989

Chironomus plumosus (Linnaeus) grp.

402.34-1504.74 (LMR)

Aartila 1988

Cladotanytarsus sp. 106-114 (UMR); 820.76-828.18 (LMR)

Battle et al. 2007; Payne et al. 1989

*Cryptochironomus sp. 402.34-1504.74 (LMR); 0-1393.69 (UMR); 131.32-1361.18 (LMR)

Aartila 1988; Canfield et al. 1998

Cryptotendipes sp. 106-114 (UMR) Battle et al. 2007

Dicrotendipes sp. 0-1393.69 (UMR); 106-114 (UMR); 820.76-828.18 (LMR)

Angradi et al. 2009; Battle et al. 2007; Payne et al. 1989

Einfeldia sp. 402.34-1504.74 (LMR)

Aartila 1988

*Gillotia sp. 131.32-1361.18 (LMR)

*Glyptotendipes sp. 0-1393.69 (UMR); 106-114 (UMR); 814.33-910.89 (LMR); 820.76-828.18 (LMR); 131.32-1361.18 (LMR)

Angradi et al. 2009; Battle et al. 2007; Beckett et al. 1983; Payne et al. 1989

Goeldichironomus sp. 402.34-1504.74 (LMR)

Aartila 1988

Harnischia sp. 106-114 (UMR) Battle et al. 2007

*Lipiniella sp. 131.32-1361.18 (LMR)

Microchironomus sp. 402.34-1504.74 (LMR); 106-114 (UMR)

Aartila 1988; Battle et al. 2007

Microtendipes sp. 106-114 (UMR) Battle et al. 2007

55

*Parachironomus sp. 131.32-1361.18 (LMR)

*Paracladopelma sp. 106-114 (UMR); 131.32-1361.18 (LMR)

Battle et al. 2007

Paralauterborniella nigrohalterale (Malloch)

106-114 (UMR) Battle et al. 2007

*Paratendipes basidens Townes 131.32-1361.18 (LMR)

Paratendipes connectens Townes 402.34-1504.74 (LMR)

Aartila 1988

*Polypedilum sp. 0-1393.69 (UMR); 106-114 (UMR); 811.11-910.89 (LMR)

Angradi et al. 2009; Battle et al. 2007; Beckett and Pennington 1986

Polypedilum convictum (Walker) 402.34-1504.74 (LMR); 106-114 (UMR); 820.76-828.18 (LMR)

Aartila 1988; Battle et al. 2007; Payne et al. 1989

*Polypedilum flavum (Johannsen) 131.32-1361.18 (LMR)

*Polypedilum halterale (Coquillett) grp.

402.34-1504.74 (LMR); 131.32-1361.18 (LMR)

Aartila 1988

Polypedilum scalaenum (Schrank) grp.

402.34-1504.74 (LMR); 106-114 (UMR)

Aartila 1988; Battle et al. 2007

Rheotanytarus sp. 402.34-1504.74 (LMR); 0-1393.69 (UMR); 106-114 (UMR); 811.11-910.89 (LMR); 820.76-828.18 (LMR)

Aartila 1988; Angradi et al. 2009; Battle et al. 2007; Beckett and Pennington 1986; Payne et al. 1989

Robackia sp. 106-114 (UMR) Battle et al. 2007

*Robackia claviger (Townes) 402.34-1504.74 (LMR); 811.11-910.89 (LMR); 131.32-1361.18 (LMR)

Aartila 1988; Beckett and Pennington 1986; Beckett et al. 1983

*Saetheria sp. 131.32-1361.18 (LMR)

Stempellina sp. 106-114 (UMR); 0-1393.69 (UMR)

Battle et al. 2007; Canfield et al. 1998

Stenochironomus sp. 402.34-1504.74 (LMR); 106-114 (UMR)

Aartila 1988; Battle et al. 2007

Stictochironomus sp. 106-114 (UMR) Battle et al. 2007

Stictochironomus caffrarius Kieffer grp.

106-114 (UMR) Battle et al. 2007

Tanytarsus sp. 402.34-1504.74 (LMR); 106-114 (UMR); 820.76-828.18 (LMR)

Aartila 1988; Battle et al. 2007; Payne et al. 1989

Tanypus sp. 811.11-910.89 (LMR)

Beckett and Pennington 1986; Beckett et al. 1983

Xenochironomus sp. 814.33-910.89 (LMR)

Beckett et al. 1983

56

*Zavrelia sp. 131.32-1361.18 (LMR)

Diamesinae Pagastia sp. 0-1393.69 (UMR) Canfield et al. 1998

Orthocladinae Corynoneura sp. 106-114 (UMR) Battle et al. 2007

Corynoneura celeripes Winnertz 402.34-1504.74 (LMR)

Aartila 1988

Corynoneura taris Roback 402.34-1504.74 (LMR)

Aartila 1988

*Cricotopus sp. 106-114 (UMR); 820.76-828.18 (LMR); 131.32-1361.18 (LMR)

Battle et al. 2007; Payne et al. 1989

Cricotopus/Orthocladius

sp. 0-1393.69 (UMR); 106-114 (UMR)

Angradi et al. 2009; Battle et al. 2007

Epoicocladius sp. 106-114 (UMR) Battle et al. 2007

Eukiefferiella sp. 820.76-828.18 (LMR)

Payne et al. 1989

Hydrobaenus sp. 402.34-1504.74 (LMR); 106-114 (UMR)

Aartila 1988; Battle et al. 2007

*Lopescladius sp. 402.34-1504.74 (LMR); 106-114 (UMR); 131.32-1361.18 (LMR)

Aartila 1988; Battle et al. 2007

*Metriocnemus fuscipes (Meigen) 131.32-1361.18 (LMR)

Microspectra sp. 820.76-828.18 (LMR)

Payne et al. 1989

*Nanocladius sp. 402.34-1504.74 (LMR); 106-114 (UMR); 820.76-828.18 (LMR); 131.32-1361.18 (LMR)

Aartila 1988; Battle et al. 2007; Payne et al. 1989

Orthocladius sp. 402.34-1504.74 (LMR); 106-114 (UMR)

Aartila 1988; Battle et al. 2007

Rheosmittia sp. 402.34-1504.74 (LMR)

Aartila 1988

*Rheosmittia arcuata Caldwell 131.32-1361.18 (LMR)

Smittia sp. 106-114 (UMR) Battle et al. 2007

Thienemanniella sp. 106-114 (UMR); 820.76-828.18 (LMR)

Battle et al. 2007; Payne et al. 1989

Prodiamesinae Prodiamesa sp. 0-1393.69 (UMR) Canfield et al. 1998

Tanypodinae *Ablabesmyia sp. 106-114 (UMR) ; 131.32-1361.18 (LMR)

Battle et al. 2007

Ablabesmyia annulata Say 106-114 (UMR) Battle et al. 2007

Ablabesmyia cinctipes (Johannsen)

402.34-1504.74 (LMR)

Aartila 1988

*Coelotanypus sp. 402.34-1504.74 (LMR); 106-114 (UMR); 131.32-1361.18 (LMR)

Aartila 1988; Battle et al. 2007

Pentaneura sp. 825.59-828.18 (LMR)

Bingham et al. 1982

57

Procladius sp. 402.34-1504.74 (LMR); 106-114 (UMR); 0-1393.69 (UMR)

Aartila 1988; Battle et al. 2007; Canfield et al. 1998

Tanypus sp. 106-114 (UMR) Battle et al. 2007

Tanypus stellatus Coquillett 402.34-1504.74 (LMR)

Aartila 1988

Telopelopia sp. 106-114 (UMR) Battle et al. 2007

Thienemannimyia grp. 402.34-1504.74 (LMR); 106-114 (UMR)

Aartila 1988; Battle et al. 2007

Empididae 402.34-1504.74 (LMR)

Aartila 1988

Hemerodromia sp. 0-1393.69 (UMR); 106-114 (UMR)

Angradi et al. 2009; Battle et al. 2007

Psychodidae Psychoda sp. 106-114 (UMR) Battle et al. 2007

Scathophagidae 106-114 (UMR) Battle et al. 2007

Simuliidae 106-114 (UMR); 1.61-305.78 (MMR); 820.76-828.18 (LMR)

Battle et al. 2007; Hoover et al. 2007; Payne et al. 1989

Cnephia pecuarum (Riley) 249.45-1375.99 (LMR)

Hoover et al. 2007

Stratiomyidae 1.61-305.78 (MMR) 249.45-1375.99 (LMR)

Hoover et al. 2007

Tipulidae 106-114 (UMR) Battle et al. 2007

Limonia sp. 0-1393.69 (UMR) Angradi et al. 2009

Hemiptera *Corixidae 0-1393.69 (UMR); 249.45-1375.99 (LMR) 1.61-305.78 (MMR); 131.32-1361.18 (LMR)

Angradi et al. 2009; Hoover et al. 2007

Non-Insecta

Turbellaria Planariidae 106-114 (UMR) Battle et al. 2007

Dugesia tigrina Girard 402.34-1504.74 (LMR); 820.76-828.18 (LMR)

Aartila 1988; Payne et al. 1989

Rotifera 402.34-1504.74 (LMR)

Aartila 1988

Tardigrada 402.34-1504.74 (LMR)

Aartila 1988

Nematoda 402.34-1504.74 (LMR); 0-1393.69 (UMR); 106-114 (UMR); 1.61-305.78 (MMR) 249.45-1375.99 (LMR)

Aartila 1988; Angradi et al. 2009; Battle et al. 2007, Hoover et al. 2007

Oligochaeta 106-114 (UMR); 131.32-1361.18 (LMR)

Battle et al. 2007

Aeolosomatidae Aeolosoma sp. 402.34-1504.74 (LMR)

Aartila 1988

Enchytraeidae Barbidrilus paucisetus Loden and Locy

402.34-1504.74 (LMR)

Aartila 1988

58

Lumbricidae 825.59-828.18 (LMR)

Bingham et al. 1982

Lumbriculidae 814.33-910.89 (LMR)

Beckett et al. 1983

Naididae Dero sp. 825.59-828.18 (LMR)

Bingham et al. 1982

Nais sp. 0-1393.69 (UMR) Angradi et al. 2009

Nais communis Piguet 402.34-1504.74 (LMR)

Aartila 1988

Pristina foreli Piguet 402.34-1504.74 (LMR)

Aartila 1988

Pristina idrensis Sperber 402.34-1504.74 (LMR)

Aartila 1988

Pristina osborni (Walton) 402.34-1504.74 (LMR)

Aartila 1988

Pristina sima (Marcus) 402.34-1504.74 (LMR)

Aartila 1988

Pristina sp. 0-1393.69 (UMR) Angradi et al. 2009

Tubificidae Aulodrilus sp. 0-1393.69 (UMR) Angradi et al. 2009

Aulodrilus pigueti Kowalewski 811.11-910.89 (LMR)

Beckett and Pennington 1986; Beckett et al. 1983

Aulodrilus pluriseta Piquet 825.59-828.18 (LMR)

Bingham et al. 1982

Ilyodrilus templetoni (Southern)

811.11-910.89 (LMR); 825.59-828.18 (LMR)

Beckett and Pennington 1986; Beckett et al. 1983; Bingham et al. 1982

Limnodrilus sp. 0-1393.69 (UMR) Angradi et al. 2009; Canfield et al. 1998

Limnodrilus cervix Brinkhurst 814.33-910.89 (LMR); 825.59-828.18 (LMR)

Beckett et al. 1983; Bingham et al. 1982

Limnodrilus claparedianus Ratzel

811.11-910.89 (LMR)

Beckett and Pennington 1986

Limnodrilus hoffmeisteri Claparede

811.11-910.89 (LMR); 825.59-828.18 (LMR)

Beckett and Pennington 1986; Beckett et al. 1983; Bingham et al. 1982

Limnodrilus maumeensis Brinkhurst and Cook

402.34-1504.74 (LMR)

Aartila et al. 1988

Peloscolex multisetosis (Smith) 825.59-828.18 (LMR)

Bingham et al. 1982

Peloscolex superiorensis Brinkhurst and Cook

825.59-828.18 (LMR)

Bingham et al. 1982

59

Tubifex sp. 840.88-989.91 (UMR)

Eckblad 1986

Tubifex newaensis (Michaelsen)

825.59-828.18 (LMR)

Bingham et al. 1982

Varichaetadrilus sp. 0-1393.69 (UMR) Angradi et al. 2009

Hirudinea 106-114 (UMR) Battle et al. 2007

Crustacea 106-114 (UMR) Battle et al. 2007

Cladocera 1.61-305.78 (MMR) 249.45-1375.99 (LMR)

Hoover et al. 2007

Daphniidae Daphnia sp. Pool 19 (UMR) Jude 1973

Copepoda Diaptomidae Diaptomus sp. Pool 19 (UMR) Jude 1973

Leptodoridae Leptodora sp. Pool 19 (UMR) Jude 1973

Parastenocarididae Parastenocaris sp. 402.34-1504.74 (LMR)

Aartila 1988

Isopoda 106-114 (UMR); 1.61-305.78 (MMR) 249.45-1375.99 (LMR)

Battle et al. 2007, Hoover et al. 2007

Asellidae 106-114 (UMR) Battle et al. 2007

Assellus sp. 840.88-989.91 (UMR)

Eckblad 1986

Lirceus sp. 814.33-910.89 (LMR); 825.59-828.18 (LMR)

Beckett et al. 1983; Bingham et al. 1982

Amphipoda 106-114 (UMR); 249.45-1375.99 (LMR)

Battle et al. 2007, Hoover et al. 2007

Corophiidae Apocorophium lacustre (Vanhoffen)

0-1393.69 (UMR); 820.76-828.18 (LMR)

Angradi et al. 2009; Payne et al. 1989

Corophium sp. 814.33-910.89 (LMR)

Beckett et al. 1983

Dogielinotidae Hyalella azteca Saussure 0-1393.69 (UMR) Angradi et al. 2009; Canfield et al. 1998

Gammaridae Gammarus sp. 0-1393.69 (UMR); 825.59-828.18 (LMR)

Angradi et al. 2009; Bingham et al. 1982

Decapoda 106-114 (UMR) Battle et al. 2007

Palaemonidae Macrobrachium ohione (Smith) 1.61-305.78 (MMR) 249.45-1375.99 (LMR)

Hoover et al. 2007

Ostracoda Pool 19 (UMR); 131.32-1361.18 (LMR)

Jude 1973

Arachnida 825.59-828.18 (LMR)

Bingham et al. 1982

Acari 106-114 (UMR) Battle et al. 2007

Hydracarina 820.76-828.18 (LMR)

Payne et al. 1989

Gastropoda 106-114 (UMR); 825.59-828.18 (LMR)

Battle et al. 2007; Bingham et al. 1982

Hydrobiidae Fontigens sp. 552.33-582.12 (UMR)

Jahn and Anderson 1986

60

Somatogyrus sp. 552.33-582.12 (UMR)

Jahn and Anderson 1986

Planorbidae Ferrissia sp. 820.76-828.18 (LMR)

Payne et al. 1989

Pleuroceridae Lithasia armigera (Say) 820.76-828.18 (LMR)

Payne et al. 1989

Pleurocera sp. 552.33-582.12 (UMR); 820.76-828.18 (LMR)

Jahn and Anderson 1986; Payne et al. 1989

Viviparidae Campeloma sp. 552.33-582.12 (UMR); 820.76-828.18 (LMR)

Jahn and Anderson 1986; Payne et al. 1989

Bivalvia Corbiculidae Corbicula sp. 106-114 (UMR) Battle et al. 2007

Corbicula fluminea (Müller) 0-1393.69 (UMR); 811.11-910.89 (LMR); 820.76-828.18 (LMR)

Angradi et al. 2009; Beckett and Pennington 1986; Beckett et al. 1983; Payne et al. 1989

Dreissinidae Dreissena polymorpha (Pallas) 106-114 (UMR) Battle et al. 2007

Dreissena sp. 1.61-305.78 (MMR) 249.45-1375.99 (LMR)

Hoover et al. 2007

Sphaeriidae Musculium sp. 552.33-582.12 (UMR)

Jahn and Anderson 1986

Musculium transversum (Say) 811.11-910.89 (LMR); 0-1393.69 (UMR); 552.33-582.12 (UMR)

Beckett and Pennington 1986; Beckett et al. 1983; Canfield et al. 1998; Jahn and Anderson 1986

Sphaerium sp. 825.59-828.18 (LMR)

Bingham et al. 1982

Sphaerium striatinum(Lamarck)

552.33-582.12 (UMR)

Jahn and Anderson 1986

Unionidae Actinonaias ligamentina carinata (Barnes)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Alasmidonta marginata Say 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Amblema plicata (Say) 840.88-989.91 (UMR)

Eckblad 1986

Arcidens confragosus (Say) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Cyclonaias tuberculata (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Ellipsaria lineolata (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Elliptio crassidens (Lamarck)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Elliptio dilatata (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

61

Fusconaia ebena (Lea) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Fusconaia flava (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Lampsilis cardium Rafinesque 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Lampsilis higginsii (Lea) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Lampsilis siliquoidea (Barnes) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Lampsilis teres (Rafinesque) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Lasmigona complanata (Barnes)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Leptodea fragilis (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Ligumia recta (Lamarck) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Megalonaias nervosa (Rafinesque)

840.88-989.91 (UMR); 255.89-1393.69 (UMR)

Eckblad 1986; Van Der Schalie and Van Der Schalie 1950

Obliquaria reflexa Rafinesque 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Obovaria olivaria (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Plethobasus cyphus (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Pleurobema sintoxia (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Potamilus alatus (Say) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Potamilus capax (Green) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Potamilus ohiensis (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Pyganodon grandis (Say) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Quadrula metanevra (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Quadrula nodulata (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

62

Quadrula pustulosa (Lea) 840.88-989.91 (UMR); 255.89-1393.69 (UMR)

Eckblad 1986; Van Der Schalie and Van Der Schalie 1950

Quadrula quadrula (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Simpsonaias ambigua (Say) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Strophitus undulatus (Say) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Toxolasma parvum (Barnes) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Tritogonia verrucosa (Rafinesque)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Truncilla donaciformis (Lea) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Truncilla truncata Rafinesque

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Utterbackia imbecillis (Say) 255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

Venustaconcha ellipsiformis (Conrad)

255.89-1393.69 (UMR)

Van Der Schalie and Van Der Schalie 1950

[RKM = river kilometer; UMR=Upper Mississippi River (Lake Itasca, MN-St. Louis, MO); MMR=Middle Mississippi River (St. Louis, MO-Cairo, IL); LMR=Lower Mississippi River (Cairo, IL-Gulf of Mexico)] *Asterisks (*) indicate macroinvertebrates found in my study

63

APPENDIX C

LIFE HISTORY COMPONENTS OF STURGEON PREY ITEMS

Prey Taxa Associated Habitat

Habit Functional Feeding Group

Reference(s)

Insecta

Ephemeroptera

Caenidae

Brachycercus sp.

Lotic-depositonal (sand with silt on top)

Sprawler Collector-gatherer

Edmunds et al. 1976

Ephemeridae

Hexagenia sp.

Lotic and lentic-depositional (sand-silt)

Burrower Collector-gatherer; Filterer

Merritt et al. 2008

Heptageniidae Lotic and lentic-erosional

Clinger Scraper; Facultative collector-gatherer

Merritt et al. 2008

Leptophlebiidae

Leptophlebia sp.

Lotic-erosional (sediments and detritus)

Swimmer; Clinger; Sprawler

Collector-gatherer; Facultative shredder-detritivore

Merritt et al. 2008

Palingeniidae

Pentagenia vittigera (Walsh)

Lotic-depositional (hard clay banks, large rivers)

Burrower Collector-gatherer; Passive filterer

Merritt et al. 2008

Polytimarcyidae

Tortopus puella (Pictet)

Lotic-depositional (hard clay banks, large rivers)

Burrower Collector-gatherer

Merritt et al. 2008

Pseudironidae

Pseudiron centralis (McDunnough)

Lotic-depositional (large rivers on sand)

Sprawler Predator (engulfer, uses vortices to search for prey)

Merritt et al. 2008

Siphlonuridae

Generally lentic

Swimmer; Climber

Collector-gatherer

Merritt et al. 2008

Ephemeroidea undetermined

Burrower Edmunds et al. 1976

Hemiptera

Corixidae Generally lentic

Generally swimmers

Generally piercer-

Merritt et al. 2008

64

(vascular hydrophytes); Lotic-depostional (vascular hydrophytes)

herbivores; Some predators (engulfers and piercers) or scrapers)

Trichoptera

Hydropsychidae

Hydropsyche sp.

Lotic-erosional

Clinger (net spinner, fixed retreat)

Collector-filterer

Merritt et al. 2008

Potamyia flava

Lotic-erosional (larger rivers)

Clinger (net spinner, fixed retreat)

Collector-filterer

Merritt et al. 2008

undetermined Hydropsychidae

Generally lotic-erosional

Clinger (net spinner, fixed retreat)

Collector-filterer

Merritt et al. 2008

Diptera Ceratopogonidae

Probezzia sp. Lentic-littoral and limnetic

Burrower; Occasionally planktonic

Predator (engulfer)

Merritt et al. 2008

Chaoboridae

Chaoborus sp.

Lentic-limnetic, profundal, and littoral

Sprawler (day); Planktonic (night)

Predator (engulfer)

Merritt et al. 2008

Chironomidae

Ablabesmyia sp.

Lotic-erosional and depositional; Lentic-littoral

Sprawler Predator (engulfer and piercer); Collector-gatherer (early instars)

Merritt et al. 2008

Chernovskiia sp.

Lotic (sandy areas of deep rivers)

Burrower Cranston 2010, Epler 2001, Merritt et al. 2008

Chironomus spp.

Lotic-depositional; Lentic-littoral and profundal

Burrower (tube builder)

Collector-gatherer (a few filterers); shredder-herbivore

Merritt et al. 2008

Coelotanypus sp.

Lentic-littoral; Lotic (slower portions of streams and rivers)

Burrower Predator (engulfer)

Cranston 2010, Epler 2001, Merritt et al. 2008

Cricotopus sp.

Lentic (vascular hydrophytes); Lotic-erosional and depositional

Clinger (tube builder); Burrower (miner and tube builder)

Shredder-herbivore; Collector-gatherer

Merritt et al. 2008

Cryptochironomus sp.

Lotic and Lentic (sandy substrata)

Burrower Predator (engulfer)

Epler 2001, Merritt et al. 2008

65

Gillotia sp. Lotic (sandy rivers)

Burrower Collector-gatherer (a few filterers); shredder-herbivore

Merritt et al. 2008

Glyptotendipes sp.

Lentic-littoral and profundal; Lotic-depositional (rarely)

Burrower (miner and tube builder); Clinger (net builder)

Shredder-herbivore; Collector-fliterer and gatherer

Merritt et al. 2008

Limpiniella sp. Lotic and Lentic (sandy substrata)

Cranston 2010, Epler 2001

Lopescladius sp.

Lotic (sandy substrata)

Sprawler Collector-gatherer (a few filterers); shredder-herbivore

Cranston 2010, Epler 2001, Merritt et al. 2008

Metriocnemus fuscipes (Meigen)

Wide variety of habitats (pitcher plants, pools, moss, tree holes, rivers, streams, lakes)

Burrower; Sprawler

Collector-gatherer; Predator (engulfer)

Cranston 2010, Epler 2001, Merritt et al. 2008

Nanocladius sp.

Lotic-erosional; Lentic-littoral

Sprawler Collector-gatherer

Merritt et al. 2008

Parachironomus sp.

Lotic and Lentic (miners and ectoparasites)

Sprawler Predator (engulfer); Collector-gatherer; Parasite

Epler 2001, Merritt et al. 2008

Paracladopelma sp.

Lotic (usually) and Lentic (sandy substrata)

Sprawler Cranston 2010, Epler 2001

Paratendipes basidens Townes

Lotic (sandy substrata)

Burrower Collector-gatherer

Epler 2001, Merritt et al. 2008

Polypedilum flavum (Johannsen)

Lotic (commonly)

Epler 2001, Merritt et al. 2008

Polypedilum halterale (Coquillett) grp.

Lentic (vascular hydrophytes)

Climber; Clinger

Shredder-herbivore (miner); Collector-gatherer; Predator (engulfer)

Epler 2001, Merritt et al. 2008

Polypedilum sp.

Lentic (vascular hydrophytes)

Climber; Clinger

Shredder-herbivore (miner); Collector-gatherer; Predator (engulfer)

Epler 2001, Merritt et al. 2008

Robackia claviger (Townes)

Lotic (sandy substrata)

Burrower Collector-gatherer

Epler 2001

66

Rheosmittia arcuata Caldwell

Lotic (sandy substrata)

Burrower Epler 2001, Merritt et al. 2008

Saetheria sp. Lotic (sandy substrata)

Epler 2001, Merritt et al. 2008

Zavrelia sp. Lotic Climber; Sprawler; Clinger (portable, mineral tube builder)

Collector-gatherer

Merritt et al. 2008

Chironomini undetermined (Pupae)

Cosmopolitan

Orthocladiinae undetermined

Cosmopolitan

Tanypodinae Cosmopolitan

Oligochaeta Cosmopolitan Pennak 1953

Hirudinea Cosmopolitan

Pennak 1953

Ostracoda Cosmopolitan

Pennak 1953

Amphipoda Cosmopolitan

Pennak 1953

Gammaridae Cosmopolitan

Corophiidae Cosmopolitan

Actinopterygii Perciformes undet.

67

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