Iowa State University Capstones, Theses and Retrospective Theses and Dissertations Dissertations

1948 An ecological study of the minnows of the Des Moines River, Boone County, Iowa William Charles Starrett Iowa State College

Follow this and additional works at: https://lib.dr.iastate.edu/rtd Part of the Agriculture Commons, Aquaculture and Fisheries Commons, and the Zoology Commons

Recommended Citation Starrett, William Charles, "An ecological study of the minnows of the Des Moines River, Boone County, Iowa " (1948). Retrospective Theses and Dissertations. 13571. https://lib.dr.iastate.edu/rtd/13571

This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Retrospective Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. INFORMATION TO USERS

This manuscript has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissertation copies are in typewriter face, while others may be from any type of computer printer.

The quality of this reproduction is dependent upon the quality of the copy submitted. Broken or indistinct print, colored or poor quality illustrations and photographs, print bieedthrough, substandard margins, and improper alignment can adversely affect reproduction.

In the unlikely event that the author did not send UMI a complete manuscript and there are missing pages, these will be noted. Also, if unauthorized copyright material had to be removed, a note will indicate the deletion.

Oversize materials (e.g., maps, drawings, charts) are reproduced by sectioning the original, beginning at the upper left-hand corner and continuing from left to right in equal sections with small overiaps.

ProQuest Information and Learning 300 North Zeeb Road, Ann Artsor, Ml 48106-1346 USA 800-521-0600

NOTE TO USERS

This reproduction is the best copy available.

UMI

AN ECOLOOICAL STUDY OF THE MINNOWS OF THE DES MOINFS RIVER, BOONE COUNTY, IOWA

by

William Charles Starrstt

A Thesis Submitted to the Graduate Faculty for the Oeijree of

DOCTOR OF PHILOSOPHY

Major Subject:. EQo;>pmio Zoology

Approred:

Signature was redacted for privacy. in/charge of Major Work

Signature was redacted for privacy.

Signature was redacted for privacy.

DeanoftJraduate College

Iowa State College

1948 UMI Number: DPI2259

® UMI

UMI Microform DP12259 Copyright 2005 by ProQuest Information and Learning Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code.

ProQuest Information and Learning Company 300 North Zeeb Road P.O. Box 1346 Ann Arbor, Ml 48106-1346 QL63S.C9

StZfla

TABLE OP CONTENTS

I. INTRODUCTION 1

II. DESCRIl-TION 0? THE Rb;SEABCH AREA 3

III. METHODS AND MATERIALS 13

IV. AN ANNOTATED LIST OF THE FISHES OF BOONE COUNTY, lO.VA 18

V. DISTRIBUTION AND ABUNDANCE OP BOONE COUNTY i'lNNOVVS AND DARTZRS 27

A. quantitative Samplln^i Methods 87 B. Distribution of the Minnows and Darters .... 31 C. Hourly and Seasonal Changes In Habitat Usage . . 45 D. Discussion 49

VI. n.-rSCI/IC COKPLTITION FOR FOO J OF TH? DES 0IN23 P.IV::R LIINNOWS 54

. Jeneral . 54 B. Feeding Trends ...... 55 G. Principal Food Items 59 1. Plankton and bottom microflora 59 2. Plant material .69 d. Terrestial invertebrates 71 4. Aquatic nymphs and larvae ...... 72 5. Adult and eraergini^ Dlptera 75 D. Discussion 75

VII. DYMA&aCS OF A /..IOVVEST:-RfJ RlV^i MINNOv/ POPULATION . . 82

A. Changes wibhin the ixed 1 opulatlon 82 3. Spavming Perioia . 83 C* Discussion 87

VIII. fi3h::ry manhji mov. thu oes moimes river .... .103

' IX. CONCLUSIONS 108

X. SUMiMARY 109

XI. LITERATURE CITED Ill

XII. ACKN0WLED(3?.1ENTS 118

XIII. APPENDICES 120

77'PVo - 1 -

I. INTRODUCTION

Tliere are still many onsolTsd problems in the management of our fishery resources in lakes, farm ponds, reserToirs, and trout streams, but the management of these bodies of water can

be considered far advanced in comparison to our meager Icnowledge of the management of rivers. In many sections of the "idwest, rivers and streams furnish most of the fish and fishing or

possess the potentialities to yield more fish if properly

managed.

The environment in a river is much less stable than that

in most other bodies of water , and therefore it is much more difficult to study river biology and to manage fishery resources

in rivers. Extensive studies were made on the biolo.|y of the

Illinois River (Kofoid 1903, 1908; Forbes and Richardson 1920;

Richardson 1921» 1928; and others), but this river is not considerei typical of the {(Silwest. Furthermore, these studies dealt more with the taxonomy and general biology of river

organisms and were not particularly directed toward fishery

management.

Some of the most important problems in fishery management, not only in rivers but also in all bodies of water, are

associated with population dynamics; namely, changes in the

abundance of fish, species composition, and intra- and inter­

specific competition. The causes for the fluctuations of abundano* of rivar fish are for the moat part unknown. Minnows

(Cyprlnldaa) are usually ahort-llred fishes and are abundant

•Tan in relatively small areas. Taay are, taerefore, espeoially

Taluable for studies in population dynamics. The effect of

Tarious factors on a minnow population can be detected within a few yaara, whereas many years would be required to make similar obserTations on longer-lived game or commercial fish.

On the Des Moines River in Iowa, a two-year Investigation has been made on the ecology of the ninnows in that river. The objective of this investigation has been not only to increase our tcnowledge of these important forage fishest but also to leam from such a population why some species are more aucoess- ful than others in the river. - 3.

11. DESCRIPTION OF THE RESEARCH AREA

Th« DOB Moines River is the largest river flowing through

Iowa. It arises in a .glacial moraine In southwestern innesota and flove in a southeasterly direction across lona to the i.'ilas- issippi River. The Des Aiolnes is 535 miles in length and has a total drainage area of 14,500 square miles, of which 93 per cent is in agriculture (Des i-'oines River Report 1931)^. About midway in its course, it passes through Boone County, cutting a deep valley in the otherwise flat land. At one point in Boone County, 257.8 miles above the mouth of the river, the total drainage is 5,610 square miles. The stream gradient is 1.5 feet per mile for the lower 300 miles of the river which includes

Boone County. The next 80 miles have a steeper slope of 3.2 feet per mile, and in the up er part of the river the gradient is 2.2 feet per mile (Des Moines River Reoort 1931).

The average annual rainfall for the entire Des I.Ioines River watershed is 30.07 inches (Des Moines River Report 1931) and for

Boone County the aver.^ge is 31.67 inches (U. S. Dept. of Agric.

Rept. 1941). The heaviest precipitation of the year usually oc­ curs in Aiay and June, causing highwater stages in the river.

Frequently an early spring flood follows thawing and fast run-off of the water. Cloudbursts and heavy rains occasionally cause local temporary floods in summer and floods are not uncommon in early fall.

1. This report is listed in literature cited under official title: U. S. 7l8t Congress. House Doc. 682. 1931. The turbidity of the water inoreaaea with a rising river.

S«cchi diao reading!] of 10 cm. and 10.4 om. were recorded during

periolB of hijh water. During high water the turbidity ia largely causod by silt. The turbidity in perioia of low water durin : the aummer varies ivith the production of Microcystia aeruKinoaa 'iitz, in the summer of 1946 Secohi disc readinga ran:ie3 from 16.5 cm. to 35 cm.; whereas by the middle of October of that year, Migrocyatla was greatly reduced in numbera and a

Secchi disc reading of 85.75 G-.n. was recorded. The river ia covered v;ith ice from late December through the middle of f/,arch.

Durin;^ this period the water is clear.

No lavc^e atreame empty into the river in Boone County, and the run-off is carriei by a number of small temporary and a few

permanent creeks. The hillsides of the valley are partially to fully timbered (oak-hickory) and are grazed to some extent*

Suitaole land in the valley is under cultivation. The banka

bordering the river have a sparse to thick growth of willow,

cottonwoois, box elder, Americsm elm, and soft maple* The higher aiUatic plants are absent from the river, probably because of the current and constant fluctuations of water level.

The bottom of the river is chiefly sand-gravel, with sand- silt, rabble, and boulders in linited areas. At low-water levels ;iiany sand, gravel, and rubble bars appear and the remain- in^i shore line is steep cut banka with an occasional rock out- crot. The channel at low-water staies varies in depth from 1.5 to 4 feet ant in width from 10 to 40 feet. Deep holes are "• 5 — present below bars and at bends.

Silt «tas the only type of pollution observed during the course of this Investigation. In some years ulnter kills of fish have been noted by local residents.

Fish were collected at 17 places on the Des Moines in Boone

County (Figure 6), but most of the detailed studies were made at

3 stations.

Station 1 (Pilot Llound T«p., Sec. 27) was established 2 miles above a lowhead dam at Fraser. The current was slower here thajn at the other 2 principal stations and the bottom was mostly sand-silt.

Station 2 (Yell Twp., Sec. 2) at the Fraser dam was selected for the principal studies because of accessibility for seinint^ operations. The slope and locations of the bluff per­ mitted seining during periods of high water. Below the dam part of tiie channel remained open through the winter months permittin s the collection of liinnows for food habit studies.

Samd and sand-gravel were the princiial types of bottom at this station. Station 2 is approximately the halfway point on the river, 262.2 uiiles from the source and 262.8 miles from the mouth.

Station 3 (Marcy Twp., Sec. 13) was near the town of Moin- goina, 16.8 miles below station 2. liore rubble bottom is present in this locality than at other stations. During low- water stages several small rapids were present. - 6 -

Fi^gure 1. Des Moines River at Station 2 in mid-August, river atage was 0,5 feet.

1

Figure 2. Des iMoihes River at Station 2 In late Movemberi river stage was 1.10 feet. Figure 3. Dea Moines River near station 2 during high water in June. Mote the stack in the foreground for comparison witn figures 1 'and 2, River stage was 16.60 feet.

Figure 4. Des Moines River, Station 2, early June. River stage was 5.72 feet. — 8 "

Figure 5, Des k^oines River valley, Boone County, Iowa.

The other stations on the river were used only temporarily and were locate 1 between stations 2 and 3. The bottom and current at these stations were similar to the other principal stations.

la conjunction with the Des Moines River investigation» minnows were collected from a number of smaller streams in

Boone County.

The headwaters of streams examined were found to be of tile drainage origin. During a drought period in August and

September of 1947, many of the smaller streams were broken up into Intermittent pools, f.^ost of the streams in the county are small prairie creeks (Figure 7), meandering through tilled and pasture land. The banks are mainly mud and the stream bottomst sand In th« pressnos of current and sand-sllt in the pools. Emergent vegetation was found abundantly in only one stream. The widths of the streams in the area are quite indie* ative of the size of the watershed.

In the northeastern part of the county 4 streams were sampled, belonjinc^ to the Skunk River drainacje system. This river lies about 25 miles east of the Oes Moines River and is part of the Mississippi River system. All 4 streams were less than 10 feet in width at the points where collections were made.

One small stream sampled in the southwestern part of the county empties into the Raccoon River. This river is south and west of Boone County and empties into the Des Moines River Just below the City of Des Moines.

Two streams surveyed are confined larsiely to the bluffs and valley of the Des Moines River. The term bluff-creek is used herein to distinsjuish this type of stream from the raore common slug^gish prairie streams. The origin of one bluff-creek was traced to a tile draina^^e pipe approximately 4 miles west of the river.

The data pertaining to the distribution of minnows and darters are presented in a later section on the basis of stream width rather than individual stream. The collection data are listed according to the width of the stream at the point of collection and are classified as less theui 10 feet in width,

10 to 40 feet in width, and the Des Moines River. - 10 -

Station 1 Stafioni

:AV£R

MOINGQNA

MAORIDX

Figure 6. Points at which fish collections were taken in Boone County, Iowa. Figure 7. A tyiiicai siiiall prairie stre .i : in loone 'Joonty, Iowa. Tae central bi^j- laouta sniner ani northern cree»c ohub are ti^e common iuinnow in 'this type of atreatn.

•'»*e 8. Emergent ve;,et.»tion was round aDu». dantly in only one stream. Tne fathe.*^ minnow and brooi<. stickleback aboanded in this habitat. - 12

Figure 9. In late sum.ner aoi.-ie of the streams were intermittent pools. - 13

III. METHODS AND ^UTSRIALS

In this investigation it was necessary to handle minnows in lar^a quantities. Care was taken to prevent killing of any fish not needed for food or other laboratory studies.

Common sense minnow seines of 10, 20, ani 30 feet lengths were used in coiiectini^ the minnows. In beaching the seine, the baj or poctcet containin^i the fish was permitted to remain partially submer^ied rather than to expose the fish to dry sand, atmosphere, and air temperatures. The fish were then removed singly, identified, and returned to the river. If the minnows were to be T.easured, they were scooped by hand and deposited in a small floating live box. A few fiere placed in a pai as needed, n.easured, and released. This procedure permitted the hanllinci of a large collection of minnows with a minimal loss, even at air temperatures of 90° F. or more.

The term "raise nef was coined to describe a method for sampling .cid-stream populations. The seine is pullel down­ stream for approximately 10 yards and quickly raised out of the water. The catch is concentrated in the pocket of the seine.

This method was found to be quite useful in determining the mid-stream fish fauna.

Three wire traps were used in studying daily activity of the Des Moines River minnows. These traps were constructed out of quarter-inch wire mesh and built according to the following 14 - speolfioatlons: 25 by 17 by 10 Inc les with two leads* 10 inches by 7 feet. The accompanyIng photographs (Figures 10 and 11) portray the construction and operation of a minnow trap.

From the Oes :/oines River, 721 collections were made between April 9, 1946, and Movember 21, 1947; however, only 619 colleotions are included in Tables 1, 2, 3, and 5, which present the percentage of occurrence of the various species of minnows and darters found in the river. The other colleotions were omitted either because of a fouled net or inclement conditions which prevented a thorough exa/ninatlon of the catch. In streams other than the Dee Moines River, 100 collections were taken in

1947.

Throughout tnis study the measurements of the fish are In millimeters of standard length unlesf. otherwise specified. The age class of the minnows was determined by the length frequency method (Lagler, 1948, gives a description of this method) and by following the avera.je sizes of the minnows through the various seasons.

The European method of 24-hour time is used in this study.

0000 is midnight and 2359 is the equivalent of 11:59 i ,:.i.

Minnows used in the food study were collected from the Des

Moines River between April 9, 1946, and July 10, 1947, The following is a list of the seasons referred to in the food study tables: - 15 -

Spring 1946 ------April 9 through June 17

Hiih water 1946 - - - - jvine 18 through June 86

Summer 1946 ------June 27 throuj^h September 18

Fall 1946 ------September 19 throUj^h November 23

..'inter 1946-47 - - - - November 24 through March 31

Spring 1947 ------April 1 through June 1

Hitih water 1947 - - - - June 7 through July 10

A total of 3,033 ninnowat representing 19 epeoiee* were examined for determination of food habits. Afield the specimens designated for use in food studies were suffocated prior to preservation in formalin (vVebater 1943). In the laboratory the entire dijeative tract .vas exa/nineJ for food items. An eetir.ate of the volume of eacn fool item was made and recorded as per­ centage of estimate: total volume of the digestive tract. This method appeared to be more satisfactory than the 0 to 10 basis used by ^rost (134VJ), If aii item occurred only as a trace* it was recorded as 1 ^ or cent. .iith the 4 species of Dee Lloines

River :ninnowa poasessinj; lonj, coiled intestines, the contents of t.ifi iigestive tract vore exa.dined at intervals along the tract (Kraatz 1923).

t'.roder and Crawforl (1322) mention t.iat the pharyngeal teetn in minnows probably cause tae listortion of food items, rendering identification of them difficult. The food items were recorded to family and species whenever possible. The adult and emerging Diptera were particularly difficult to - 16 -

5"'-.

Figure 10. A cloi;e-up view of a wire trap used in 8tuiyin,i daily activity of Des l^oines River minnowe.

Figure 11. A minnow trap in operation on the Des ^loines River. - 17 - identify* and the families identified are included in the foot­ notes of the tables in the appendices rather than in the body of the tables. Inclusion of these data in the tables would tend to give more emphasis to a few of the more easily identifiable forms. In the text the food items ure grouped wherever possible.

No attempt was made to Identify the various species of diatoms found in each fish. The diatoms euid other forms identified from the bottom ooze samples are listed In the appendices.

The authors listed below were followed in matters pertinent to the taxonomy of the various biolof^lcal speoimene encountered in this study:

Fishes ------Hubbs (1926); Jordan (1929); Hubbs and

Lagler (1947); and Eddy and Surber (1947)

Ephemeroptera - - fJeedham, Traver, and Hsu (1935)

Plecoptera - - Frison (1935 and 1942)

Trichoptera - - - Ross (1944)

Other Insects - - Comstock (1947)

Crustacea - - - - Ward and vVhipple (1918)

Alsae ------Prescott (1931); and Smith (1933).

Other methods of study are described In later sections dlscussinti the data collected. - 18 -

IV. AN ANNOTATED LIST OF THE FISHES OF BOONE COUNTY, IOWA

In the latter part of the last century, some fish surveys were made on various parts of the Des Moines River (Jordan and irleek 1885; Meek 1892; Cox 1896). Call's (189ii) survey of the

Des Moines River bus in included a fe« Boone County streams.

Bailey and Harrison <1948) mention the more abundant apeoies of fishes occurring in the Des Moines River, Boone County. Fifty- three species of fish were found in Boone County in the earlier and present investigations. Only one of these, the redfin, was not taken in the Des Moines drainage system in Boone County.

In the following annotated list, the species marked with an asterisk (-:0 were not taken in the present study.

Emphasis in thic study was on smaller fishes and, as a result of the gear employed, some of the larger fishes known to occur in the river were either not taken or appeared in only a few collections. The percentage of occurrence in the collections for fishes other than minnows and darters is therefore sel lorr, in­ cluded because of the unreliability of the datti. A detaile i Us- oussion of abundance and distribution of the various specitg of minnows and darters is i^iven in the next section of this pa;j8r.

1. Bigfflouth buffalofiah - '.'.et^astomatobus oyprinella (Valen­

ciennes).

A few adult specimens were taken in the Des Moines River

in April, 1946. - 19 -

2. QuillbaoK - Carplodea cyprinus (Le Sueur).

The young and adults of the various species of Carpiodea

occurred in 38 per cent of tae river collections. This

species was also taicen in Beaver Creek.

3. Northern carpsuclcer - Carpiodea carpio carpio (Rafineaque).

Limited to the Des Koines River.

4. Highfin auclcer - Carplodes velifer (Raf inesque).

Limitel to the Dea i.oinea River.

5. Common white sucker - Catostoams commersonnii commersonnil

(Lacepede).

This species appeared to he rnore abundant in 1946 than in

1947. Found in small prairie streams as well aa the Des

Moines River.

6. Hog sticker - Hypentellum nit^rloans (Le Sueur).

This species occurred in 3 per cant i»f the river collec­

tions. This species was not taken in the smaller streams.

7. aoldenredaorse - l^:oxostoroa erythrurum (Rafinesque).

This si^ecies occurred only in the Des ivioines River

collections.

8. Silver redhorse * Moxostoroa anisurum (Rafinesque).

This species occurred only in the Des Moines River

collections.

9c Northern redhorse - Lloxostoma aureolum (Le Sueur).

This specieg occurred more frequently in the Des Moines

River collections than the other species of ?/.oxostoma.

Further collecting would probably Indicate that this species - 20 -

Is not oonfinsd to ths river.

10. Carp - Cyprinus carplo Linnasus.

The carp is second in importance as a food fish in Boons

County. This species is much more abundant than is indi­

cated by its occurrence in 6 per cent of the Dee Moines

River collections. The carp was not taken in streams less

than 10 feet in width.

11. Northern creek chub - Semotilus atromaculatus atromacul-

atus (Mitchill).

This minnow was found to be more abundant in the smaller

streams than in the Des Moines River.

12. Hornyhead chub - Nocomis bij^uttatus (Kirtland).

This species occurred in the Des Moines River and small

stream collections only occasionally. Not abundant in

Boone County.

13. Silver chub - Hybopsis storeriapus (Kirtland).

Confined to the Des Moines River. Fairly common.

14. Speckled dace - Extrarlus aestivalis (Oirard).

Common in the Des Moines River. A few specimens were taksn

in Beaver Creek.

15. Spotted chub - Erimystax sp.

Two specimens taken from the Des l.'oine8 River in 1946 were

checked by Dr. C. L. Hubbs. A revision of the genus Erlmys-

tax is now being prepared by Drs. Hubbs and Crowe.

16. Vfestem blacknose dace - Rhinlchthys atratulus meleagrls

Agassiz. - 21 -

This species ocourrad in only 2 of the Des Moines RlTsr

collections. In Boone County this daoe is common in small

bluff-creeks.

17. .western golden shiner- Wotemit^onus crysoleuoaa auratus

('^.af ineaque).

un July 9, 1947, 6 specimens were taken from a temporary

pool adjacent to the Des Moines River subsequent to a hi^sh-

water period. This species may be present in some numbers

In the deeper waters above the lowhead Janis in the Des

;oinea. However none waa taken in collections from such

svaters. Near Iioinaona, 1 specimen was taken in April, 1946.

18. Common emerald shiner - Notropis atherlnoldee atherinoides

laf inesque.

'Jot comruon. Confined to the Des I.'.oinea River.

19. Uosyface ahiner - Notropis rubellus (Agassiz).

Fairly common. Confined to the Des Moines River.

20. northern common shiner - Notropis cornutua frontalis

(Agassiz).

Common in the Des Moines River and smaller streams through­

out the county.

31. Spotfin shiner - Notropis spilopterus (Coj^e).

Common in the Des Moines River -nd was found to occur in

lesser numbers in tributary streams over 10 feet in width.

This species was not found in the Skunk River drainage in

loone County. - 22 -

Reifin - 'otrof Is 1 itrenaie lutrensi» (Raird and (lirard).

Mo recorlg of this a[,ecies occurring in the D®s ''olnes

^Iver >ni tributary atrea s in "^oone "O'lnty. It was found to occurfairly abundantly in Squnw OreoJc In the Skunk River drainatje.

River shiner - Tjotropis blenviius ( >lrerd).

^ot coraion. Confined to tae r>efl I'oinea liver.

Central bi ^mouth aninor ~ '.'otropia dorsalle dorsal is

(a,ia33ia).

Coinmon. Found abuniantly in streams of all wiiths in the county.

Pouthwestern aand ahiner - Notropis dellcioaua deliciosua

C Jirard).

"o.imon. Lar^jely confined to streams over 10 fe^t in wiith.

/i thoroa^^h taxono.nic study of this a'.ecies in '^oone County

•li^^ht establish the ^jreaence of intergradations between deliciosus and missourienais. Variation was foan 1 in -J

populations studied, indicating a tendency toward such

inter.5radation.

T'o-eka sliiner - Wotropia topeka (gilbert).

:o speclraena were taken from the Oea J^oines River during

the course of this investir^ation. In the Iowa State College iiuseura taere is 1 specimen collected by Or. R. M. Bailey

fro.'a the Dea Moines River in Boone County on September 24,

1359. This species was found to be fairly common in Beaver

Creek, a tributary of the Dea Moinea. 23 -

27. Suckermouth minnow - Phenaoobius mirabilis Oirard).

Fairly common in the Des 'i^olnes River and smaller streams

in the county over 10 feet in width.

28. Brassy minnow - H.ybo.^nathua hankinsoni Hubbs

Found in limited number?. In strearas of all sizes.

29. Fathead minnow - i itnephales promelaa promelaa (Raf inesqus).

Fairly common in the Dea ii'oines River. Found throughout

the coanty, however, was taken abundantly in a small

unnamei stream in the southwestern part of the county

(Union Tw;i., Sec. 88).

30. Bullhead minnow - Ceratlchthva perspicuus (Oirard).

Common. Confinel to the Dea ".'oines River.

31. Bluntnose minnow - Hyborhynchua notatua (Rafinesque).

Common, round largely in streams over 10 feet in width.

32. Central stoneroller - Gampostorna anomalum pullum (Agassis).

This species was not found to occur abuniintly in 3oons

County streams. 33. Southern channel catfish - Ictalurus lacustris punctatus

(Rafinesque).

This species occurred in 15 per cent of the Des Moines River collections. Specimens were not taken elaewhere in

the county.

34. Northern black bullhead •* Amaiurus melas mslas (Rafinesque).

Found in all sizes of streams. Not abundant in the Oes

Moines River. . 24.

35. Plftthead eatflah - Filodlctxia ollvarls (RafIneaque),

Paw apaolmana taken by anglers from Des Moines Rirar were

obaerred.

3 6. Stoneoat - Noturua flavua RafIneaque.

Not abundant in Des I^lolnea River. Pew apaolmana taken in

smaller streama.

37. northern pike - Saox laciua Linnaeua.

Few specimens taken in Des Moinea River. Not common.

38. Aifierican eal* - Anftuilla bostonienala (Le Suevir).

One specimen 435 mm. total lenjjth in Iowa State College

. uaeum taken from Oes Moinea River, Boone County, by :ir.

aurice F. Baker on July 10, 1937.

39. Yellow perch - I erca flaveacens (Mitchill).

Not comriton. A few small apecimens were taken from the Des

koines River in 1946 and 1947.

40. Yellow pikeperch - Stizostedion vitraum vitreum (Mitchill).

Confined to the Des Moines River. Not abundant.

41. Blacksided darter - Hadropterua maculatua (airard).

Fairly common. Confined to Des Moines River collections.

43. Slenderhead darter - Hadropterus phoxcephalua (Nelson).

Fairly common. Confined to the Dea Moines River collec­

tions.

4vi. .astern sand darter - Ammocrypta clara (Jordan and Meek).

Fairly co.mnon. Confined to the Des Moines River.

44. Central Johnny darter - Boleosoma nigrum ni^um (Rafines-

que). - 85 -

Fairlycommon. Found in all eizea of streams.

45. "astern banded darter - Poecillohtlya aonalla gonalia

Cope.

Z apecimsna were colleoted from the Dea Moines River.

46. Striped fantail darter - Poeolliohthys flabellaria lineo-

latus (Agaaaiz).

' single specimen occurred in the Dea Moines River collec­

tions. This species was found to be fairly abundant in

the upper 5 miles of aluff Creek. No occurrences in the

other streams in the county. 47. Northern amallraouth bass - i'.icropterus dolomieu dolomieu

Lacepede.

:iot abundant in the Dea .Moines River. Younoj were found to

be coiamon in 2 tributary streams of the river.

48. .)reen aunfiah - Lepomis cyanellua Rafinesque.

This apecies occurred in 1 per cent of the Des Moines River

collections. A few specimens were taken in smaller streams.

49. Orangespotted sunfish - Lepomia humilis (Girard).

This apecies occurred in 4 per cent of the collections. A

few specimens were taken in the smaller streams.

50. "Jorthern rock bass'"^ - Ambloplitea ruoestria rupestris

(Rafinesque).

:,r. Harry a. Harrison, Jr.» of the Iowa State Conservation

joamission has in his collection a specimen of thia species

laken by him in 1946 from the Des Moines River at Fraser. - 26 -

51. White orappie - Pomoxis annalarla Rafineequa.

not. Abundant in the Dea Moines HiTer. Not taken elaewhara

in the county.

52. Black orappie* - Pomoxia nigro"maoalatua (Le Sueur).

Recorded from the river ty Bailay and 'farrison (1946).

This apeclee should be considered as acoldental in tha

Dea Moines River.

53. Brook stickleback - Suealla inconatana (Kirtland).

A ainfi^le specimen vras taken in a minnow trap in the Dea

r.oines River during hi,;!! water In 1947. This speciea ahould

be considered aa accidental in the Dea ?<'olnea River, 3oona

^^ounty. This species is confined to a single small unnamed

prairia atream in the south we.Pterin part of the cormty (Union

Twp., Sao. 28). ' Z1 "

V. DISTRleaTION AND ABUNDANCE

OF BOONE COUNTY MINNOVfS AND DARTERS

A. 4UantltatiTe Sampling Methods

In an ecological study it is usually desirable to know the approximate size of the population under obaarvation. It liad been planned to leterraine the number of minnows per sjuare yard in the Dee Lloines River as Thompson and Hunt (1930) did on the streams in Champaign County, Illinois. This method is based mainly on skilful oper-ition of a seine. Most of the streams surveye i by Thompson and Hunt were small. Even the largest streams incladed in their report do not compare in size with the Des Moines River. This method proved to be unsatisfactory for application on the Des Moinen; however, the method appeared to be of value on the smaller streams. A river the size of the

Des Moines presents obstacles in seinin^i which are usually not confronted on small streaints. r:ince data relative to minnow habitat preference were also sought, the size of the seine was necessarily limitsi. A seine length of over 30 feet was of no value in sampling a single habitat. iVith a shorter length seine the larger fish outgain the seine, even though the out­ board raaji is several yards in advance of the inboard man. The current and snags in a large river reduce the efficiency of - 28 - handling a salno and permit fish to eaoape undar tha saina.

Trial hauls were made several timea in suocesalon over a given area of v?ater and the catches revealed that not all of the fish

ware being taicen. This is particularly true for the stream

bottom species, such as the speckled dace. In a current, a aaine even with additional weights does not operate efficiently

•nough to catch all of ^he bottom dv?ellin3 fish. The applloa- tion of such data to a siquara-yard estimate cf a fish popula­ tion wo il l be inaccurate. As la described later, there are many seasonal and hourly differences in the distribution of tha fish. At 3orae periods of their li/es certain fish school In

particular habitats while at other times the same species may

be widely distributed in all parts of the river.

Knowledge of the life history of the various species is thus a prerequisite in attaraptin^ a quantitative study of river minnows. If several colleotions wore taken in a spawning area in the sorainer or in a deep pool in late fall, an unreliable

estimate of the population would be obtained. The southwestern sand shiner in June is often taken in such small numbers that a few hauls would tend to indicate a scarcity of the species as compared to hauls :aade late in the summer over a spawning area.

Also a few samples in unsuitable habitats during the spawning season or in late fall would reflect a scarcity of the spaoias.

Since these life history data were not available at the

beginning of this study, it was not possible to treat the Des . £9

Xolnea Rivar data on actual count basis.

The f in-clij. pin^i method of estimating population numbers was tried on the n.innows. This method has proven to be rather succesBful with lar^^er-sized fish in lakes and ponds (Krumholz

1944, and others). Observations made on released small fish indicated their inability to withatand tiie current ani were usually carried downstream. Over 400 minnows were fin-clipped and none was recovered. A few minnows were martei with a small hole in the lorsal fin; however, the difficulty in detecting such small markings made this method impracticable when thousands of specimens were to be exaiwined.

The size, current, and turbidity of the Des tv!oines River made it impossible to use poison or electrical shoclclnti methods effectively (Shetter and Leonard 1943; Haskell 1940).

In this study the ;iabitat preference of a species is pre­ sented in per cent based on the number of collections for a habitat divided into the number of collections in which the species occurred (Forbes and Richardson 1920). The percentage of occurrence in collections is also ised herein to ietermine the relative abundance of a species. This estimate of relative abundance appears to be a more accuratu method than actual count, provided 25 or more collections are made in an area of river not exceeding a quarter of a mile. Fewer collections would not permit an investigator to sample a sufficient number of habitats. - 30

Theoretically> the more Individuals present in an area, tiie more occurrences would be expected. The method can be de.iionstrated by a discussion of the data colleot9<^ zn the speoided dace. During the first 3.5 months of collecting in the Des Moines River, this species appeared in only a few col­ lections (Table 16); however, in late August, following a suc- cesijful spawnin.^, the occurrence of the speckled dace increased.

As indicate! in Table 1 this species shows a preference for current. In t, le latter part of 1946 and through 1947, this species fre-iiently occurred in liraited numbers in quiet stret­ ches of wat r ..ni pools. This was not noted prior to the increase in nuibers. Also, observations on other species indicate t iat the abundant species are found in varying numbers in all haoitats.

A preliminary analysis was made of the Boone County data on a sociation of the various species of minnows. The associa­ tion index (Dice 1945) in this instance mainly reveals that the sjecies are either widely distributed or occur abundantly in the habltut rather than indicating a close affinity to each other.

The association index is included for the central bigmouth s ;iner and northern creek chub merely to demonstrate its rela­ tionship to abundance of two widely distributed minnows rather than close association. - 31 -

B. Distribution of the Minnows and Darters

Ttie number of speoiea of minnows and darters in Boone

County streams increases with stream size. In streams less than

10 feet in wilth, a total of 11 species of minnows and Z species of darters were taken as comparel to 22 known species of minnows in the Des !

Hunt (1930) founJ the number of species in Champaign County increased with tho sise of the streaM's watershed. This is apparently associaterl with space, environmental factors, habitat preferences, and intornpecific relationships. The fathead min­ now was found in limited numbers in the various sizes of streams with the exception of one small unnamed stream in the south­ western .art of the county ('Jnion Twu., Sec. 28), This was the only stream surveyed having emergent vegetation i^rowin^s in the pools. Here the fathead minnow was quite abundant (range from

15 to 75 per haul). In this habitat other species of minnows were scarce, the brook stickleback being the only other abundant fish. Hubbs and Cooper (1936) et ite that the fathead minnow does not succeed under severe competition with other fishes and apparently cannot maintain itself in considerable numbers in large leikes or streams. The abundance of the fathead minnow in most of the streams is then possibly restricted by its limited tolerance to other species. - 38 -

0 iC 2'^ 30 40 50 60 70 80 1 i I 1 1 1 1

'

. ;, • • .. ... •: • . • 1

NOTROPIS CORNUTUS FRONTALIS

PHENACOBIUS MIRABlLIS 3_

HYBOGNATHUS HANKINSONI

PIMEPHALES P PRQMELAS —i ,

* NOT'<0(-iRi,IBEI I.IJS

uAr,1P05T0r.'<". A't M .^.UM •

SEMOTILUS A ATROMACl/l.flT 0'-. 1 \ 1

HYBOPSIS STORERIANUS -

p LEGEND NOTROPIS A ATHERINOIOES •••OES MOINES RIVER NOTROPIS BLENMIUS I EZ2S3STREAMS 10 TO 40 FEET IN WIDTH 1-.' • ST REAMS LESS THAN )0 FEET IN WIDTH NOCOMIS BIGUTTATUS k .1 RHINICHTHYS ATRATULUS MELEAGRIS

ERIMYSTAX SP 1 1 1 1 1 1 1 0 10 20 30 40 50 60 70 60 (PERCENTAGE OF OCCURRENCE IN COLLECTIONS)

Figure 12, The abundance of minno^ns in Boone County, Iowa, streams during 1946 and 1947. - 33 - Tabic I

Pvroratage of ooeorrane* of •iimotrs In ooUsotloM

st si I O -w •»A lii;. «a M Ot o » -ect'd ® 13 o tJ ® ih h No* eolloetloBs

Notropls splloptarua j6 91 3® 7^

Notropie delloiosns ^ 76 7h 85 11 7<

%otropia d. doraalia 71 62 93 11 u 6l

Iztrariua aaatlTalla I 9 »»9 0 55

Notropie oornutaa frontalia 57 65 3»» 36 26 ^7

Hjrborlqrnohtta notatua H6 6^ 35 7 h2 3X Caratiohthya parapiouaa 27 hi 26 0 11 «5 Fbaaaeobiua alrabilia 21 6 12 0 5 lis Rybogiiathaa hankinsonl 35 11 2 0 20 Fiaaphalaa p. proaalas 32 32 15 2 11 7 Notropia rabellua 13 1^ 7 0 O«apo«tona anoBkalvai puUua 17 9 3 0 16

Saaotllua a. atroaaoulatua _ 6 12 3 0 u 13

Cyprinua oarpio 6 15 0 5 2.

Etjrbopaia atorarianua 0 6 7 0 0 2

Notropie a. atbarinoidaa 2 3 2 u 0 1,

Notropia blanniua 0 6 3 0 0 t Nooeola biguttatua 0 0 0 0 0 ft Bhiaiahthya atratulaa •alaagria 2 1 0 0 »

Sriajrstax diaaiailia 0 0 0 0 1 *Hi4oatraam aanplea wara takan by tha "raiaa-nat* aotbod. *'^at was held at edge of iea and fiah were drifan oat froM under the ioa i^to theop«k||^

r to 5' deptt Roolcs - bott< % m i Idera cur­ o o o o o o vii ON e ovjipis'romh 5J<£oaNOvji0N0ft.0% 0-2.5» »* depth m ...JHigh-water » •4 o o o vji VJI 6 s v,i^6ss&^>8s^^8 sand-silt « no current •1 0-3» depth Eigh-water 13 Bead current « vjl O O VX OK. o o 0-3 • deptia a o s .Jttigh-water o o o o o vo vji sand-silt eurrent 0-3' depth Winter* ^aooo-q^sk^ok. Mid-strea& oo ooooeooo current 2-3' depth Winter** »- Edge of ie4 oo o oo o -p 6"-1.5' dspth

Average s •«*• i-'umjravv«vop!ir^r3

•^'able 2

Percentage of occuiTence of varlouB species of fish 1B oolleotions from straamE 10 to Uo feet in v/ldth, Boone County, Iowa*

Sand-silt :;«uid-nab- Sand-s

Notropis d. dorBali8 i2 39 ii 67

Semotilus a. atrcnaaculatus 17 k6 3»t

Notropis cornutua frontalis 16 »»3 21 29

Pioephales p. promelas 22 25 2i

Notropis spilopterus 36 17 i 17

Notropis d. delioiostts U5 9 13 17

Hybognathus hankinsoni 36 9 13 16

HyborhynchuB notatus 27 13 If 7

Notropis topeka 27 k 0 7

PhenacobiuB nirabilis 9 k 0 3

Caiapostoma anomalum pullum 0 9 0 3

Nocomie bieuttatus 0 9 0 3

Notropis 1. lutrenslB 0 k k 3

Cyprinus carpio 9 0 0 2

Rhinichthys atratulus raeleagris 0 0 k 2

Extrerius aeatlTfilif. 0 0 k 2

Other fxsheu

Carpiodea cyprinus 9 0 0 2

Catostonus c. coaunerBonnll 1^ 0 0 3 - 35 -

Table 8

Percentage of occurrence of Tariou# Bpeclee of fish in collections from strer^ns 10 to ko feet in width, Boonr County, Iow»?, (Conticufld.)

Sand-Bilt Send«> ^nd-8ome 'Werege Species"' current rubble gravel ii-Ho» (11)*» current current strflaras (23) (2'+) (59)

Amelurue n. melae 1^ 0 0 3

Noturus flaTUB 9 0 0 2

Leponie cyanellus 0 If 0 2

Lep<»iie huaillB 0 9 k 3

Moropterua d. doloaleu k 0 5

Boleosoma n. nierun 9 k 0 3

*Total number of specie®—24 " " " Cyprinida*—16 """dumber of oolleotiona taken in 19^7* Table 3

Perosntag* cf ooeurreno* of TariouB specieB of fish ia collections from streams lees than 10 feet in | | width, Boone County, Iowa* | 1 1 1 S 1 r-i0 % 1 § § « aa 3 ^ Speoies* strsla g A (6)

eurreati (D

(i) • • 4i> 10 w ^ SSL ® »< • - (23) (k)** current stream, rul| current Sand ble Sand-silt current s ^ S? Bluff rubble slight cur­ rent Band- siIt ji Prairie 0 Vegetation (X, 0 • Cyprinidae

Notropis d. dorsalis 75 96 50 75 100 35 20

SmotiluB a. atromaculatus 50 65 0 75 50 ^3 62

Notropis oornutus frontalis 25 26 50 50 0 17 60 32

Pimephales p. promalas 0 22 50 13 0 ^3 20 26

Rhinichthye atratulus meleagris 0 k 0 75 0 0 0 Ik

Byborhynchue notatus 50 0 50 25 0 0 20 12

Noeofflis biguttatus 0 13 50 0 0 0 20 10

Canpostoioa anomalom pullun 0 k 0 0 0 17 20 6 NotropiB d. deliciosus 0 9 0 13 0 0 0 6

Notropis topeka 0 0 0 0 0 33 0 k

Hybognatbus hankin&oni 0 0 0 0 0 17 0 2 Table

Percentage of occurrence of various specleB of fish In collections from streaine less than 10 feet in width, Boone County, Io;¥a* (Continued.)

r-l ' ' t TP— o t I c! «> •0 V) o u •o o s *3u "Sc •W +» 3 cJ O ^ ri q •p 4» U •P i-l O ^ <0 fi P 10 itv SpecleB'* ••2 O i-» VO <0 a —- •P — a a a ^ a <0 a s,9 I « * « « CO g ^ » +J « +J ^ - p ur\ u 4 2 0 U> -P H f-i 6C « > s ^-4- ah cm 1 d cu ^1 « « e a o ^ e (D 4< « o w o o:}S o u3 o ^— •p ih >0 1-10) o ca I* > ifl ag° «a .a a 10 ^ Pi other fishes

Ameiurus m. melas 0 0 0 0 0 17 20

Boleoeoma n. nigrum 0 13 0 0 0 0 20 Oi Catonotus flabellaris lineolatus 25 13 0 0 0 0 20 ID -a

Euealia inconatane 0 0 0 0 0 67 20 10

*Total number of specie8~15 BUBcyprinldae—11 **Number of ooUeetlons taken in - 38

The western blaoknose dace was found to be confined mainly to the upper stretohee of small bluff-oreelcs and occurred in 75 per cent of the collectiona from such streams (rant^e from 0 to

82 per haul), as couipared to 14 per cent in other streams of comparable size (Table 5). This dace occurred in only 2 Des

Moines River collections, representing Z speoimens. These sped mens were possibly recently introduced from fishermen's .uinnow

palls. The distributional data in Tables 1| 'd, and 3 indicate that the western blacknose dace is li.iited in its distribution over tae county arul that audi limitation is due to its definite habitat preference, nvhich in this case appears to be stream size and a steeper atreata eiA-siient than is present in the sluggish prairie streams. Few other species show as marlced a habitat

preference.

The hornyhead chub waa not abundant anywhere in Boone

County. It occurrsd in only 1 per cent of the river collections

According to Hubbs and Cooper (1936), this species is absent from middy, silt-bottomed, and stagnant waters and prefers swift-water streams with gravel bottoms because of its method of spawning. This species is probably limited by scarcity of such habitats in the county. The two most abundant species of minnows in the river, the spotfin shiner and the soutawestern sand shiner, are largely

confined to the Des Moines and streams over 10 feet in width (Tables 1 and Z), A few specimens of the latter were taken in - 39 streams less than 10 feat In width. These species were found in all habitats of the rivert ho.i/eyer seasonal as well as

iiurnal and nocturnal preferences were determinel and are discusseJ later.

The apeclclerl dace in Soone County was found to be confined mainly to the Oes Moines. It OGcurre 1 in only 2 par cent of the collections in atrcama between 10 and 40 feet and was not taken in any of the smaller streams. This species uses the channel of the river more than do other minnows. The scarcer silver chub was occasionally taJcen in the channel with the bottom feeder speckled dace. The spotfin shiner, southwestern sand

shiner and northern common shiner frequently occurre 1 in the channel collections (raise net), however in lesser numbers than the speckled dace. This dace* as evidenced by the 1946-47 mid- streair. winter collections (Table 4), continued to use the channel even t out^h at ot tion 3 it was not covered with ice. The other species of .uinno.vs at this station in winter were seldom col­ lected in the ice-free channel. The bullhead minnow is Unite 1 in its distribution to the

Des Moines River (Figure 1:3). This species wa;"^ found more abundantly in backwaters anl pools than in any of the other habitats. The .reference of this fish for muddy backwaters and bayoiis of large and mo lium si.iel rivers is mentioned by Hubbs and Black (1947). In the Oes iioines River it was found to be one of the more abundant species of minnows. - 40 -

The csntral bl^mouth shiner is the most successful fish

In Boone County insofar aa wide distribution and general abun­

dance are concernel. It is a pioneer fish In small creeks and

Its abundance gradually decreases with Increase in stream size

as shown jranhlcally in Piiure 12. This decrease is not tjreat

enoUi^h to prevent It from beinj one of the three most ab'andant

species la the Des Llolnes. The use of .'shlftlni sand bottom by

the paammophilois shiners is discussed by Hubbs and Ortanburjjer

(1929) and Hubba and '/Valker (1942). On several occasions, col­

lections taken over ne«l/ covered sand bars causei by a rising

river v^era composed mainly of central bitsaoatu shiners, indi-

oatlnii its ability to make use of a newly formed habitat. The

southwestern sand shiner and apotfin shiner were the trio specloa

of minnows ino3t frequently associated with the central blt^mouth shiner in the river.

The distribution of the northern oreek chub In Qoor.- '^ounty

is quite similar to th:it of the central bl^mouth shiner, however

the chub occurs in leaser numbers. The asaoclation index (Dice

1945) of the northern creek chub ta the central bi^imouth shiner

is .9v3. In this Instance the index reveals mainly that both

species are widely distributed rather than indicating a olosa

assoo iation.

The nortaera co.inaon shiner was fairly abundant In most of

the streams surveyed. This shiner is found in swift water as

well as quiet pools. In the Oes t/ioines it is usually associated - 41 -

tditi the spotfin shiner, aonthnointern sand shiner, and bluntnose

ifiinno's.

Table 4

Average number of fishes per haul in ninter 1946-47, Dea Molnsp; ^.iver

r.'id-streara Driven from Jt-ecies of minnow no ice cover (11)^ under the ice (14)

Tixtrarius aestivalis 15.0 2.7

Notropis d, deliciosus 1.5 29.9

'!otropi8 d. dorsalis 0.3 4.3

Phenacobius mirabilis 0 3.2

Notropis cornutus frontalis 0.3 1.6

^Jotropis spilopterua 0.3 1.3

a Number of coiiectioaa.

The central stoneroller was not abundant in any of the

streams. In the river this species indicated some preference

for a rubble bottom in the presence of current. The sucker-

mouth minnow was found to show an even greater preference for

this habitat than the stoneroller. Species Indicating a bottom

preference are often limited in abundance because of scarcity

of a suitable habitat.

The roeyface shiner occurred in 11 per cent of the collee-

tiona and this usually represented only a few specimens. The

adult of this species were found in association with adult •• 43 "• apotfin ahlnars. The roayface ohlner was llnlte'l in its

(iiatrlbution to the river.

The bluntnoo^ minnow v?as found to be more abundant in the river than in the smaller streams. This apecies prefers a deep* quiet pool habitat. In fall of the year in »vater tempera­ tures ranginti from 40° to 50° F., adults were found to be abun­ dant in presence of currsnt over a tjravel to aand-ailt bottoM.

In ttiia habitat tho s^-otfin slainer and northern coM.ion shiner aloo were present in fairly lar^^e numbers. This association was found to be iiabanded at temperatures below 40° F. The adult bluntnose minnows were found at the lower tamporatures with the youn^ fish in deep pools as mentioned above for this specias.

The common emerald shiner and the river shiner were present in the river in small numbers and in only 2 per cent of the oollections. These species were confined to the river in their distribution.

In f^quaw Creek, Hkunk River drainage, the redfin wao found to occur fairly abundantly. This species of minnow is limited in Boone rrounty to the Skun;c River drainage. The apotfin shiner, a species closely relate! to tae reifin (Starrett 1935), is not

Known to occur in the Skunk River drainage. Call (1892) includes the apotfin shiner as part of tn© Squaw Greek fauna; however, he ieacribes t.iis species as having either brilliant yellow or red fine which leada the present writer to believe 43 -

that Call oonfused these two distinct speoies. All male speol-

mens of the spotfln shiner in breeding colors examined from the

Oes ifolnes River had yellowish or orange-black colored fins;

whereas, the redfins from Oquaw Creek had reddish colored fins.

This is corroborated by current descriptions of these speoies

(Eddy and Surber 1947). Other characters are also used for

specific differentiation.

Only 6 specien of darters were found to occur in Boone

County. The central Johnny darter was determined to be the

moat abundant and widely distributed darter in the county.

This species did not show any particular habitat preference

(Tables 2» 3, and 5). The central Johnny darter never occurred

in numbers exceeding 15 in the Des i>1oine8 River collections.

Usually the occurrences represented a sinijle specimen.

The blacksided darter was found to be confined to the Des

Moines River, and its occurrences in the collections were

usually as a single specimen. No habitat preference was deter*

mined for this species.

The slenderhead darter was also found to be confined to

the Des Moines River. This species showed a habitat preference

for sand bottom in the presence of current. The occurrence of

this species in the collections was usually limited to a single

specimen.

The western sand darter occurred only in the Des Moines

River oolleotions. Here this species showed a habitat preference . 44 -

tabl* 5

Peroentage of ooourrenoe of darters (Etheoatomlnae) Tl

•p •pa ft s ^ i-t - •a«§ - •& I irv ta, <0 a dS' I « icf o o • ra 13I ih h itv 13 'i Ho. oolleotlcms tw 4M- Hadropterus maoolatua 9 k 0 10 15 HadropteruB phoxoephaloa 0 0 1 0 5 5

Boleoaonut a. nlgroa 1/ 11 0 16 21

Poeeiliohtbya z. zonalla 0 0 0 0 0 0

ABHOorypta olara 0 3 u 0 0 ff Catooiotua flabellarls lineolatua 0 0 0 0 0 0

*Hid»«tream safflplaa were taken by the "raise-net" awtliod* '*'*Set was held at edge of iee and flah were drlrea out from under the ie« iato tke opem ttri

CTp' ct- depth. a 4 Rooks - bou­ lder6 cur- a\ v3i m3 teat 2'-3* o depth i V Sand-gravel tr current m c;i I VX VJI 0-2,5' deptl

H Saan-ctxv ourreatt i lo v>( 9 0-2.51 depth sr o a Rubble b •3( current o o o 0\ 9n vx o k* 0-2.5' o 0 depth • Hlgh^watar w eand-silt o o o s s* s cs no current 1 0-3' depth ta High-water 0(L o o VIoi 04tu ro sand curresl 1 0-3» depth

High-water '< o o « & sand-silt current vo 0-3' depth •Ir Winter* O O VO o o o Mid-stream current 2-3' depth Winter** Edge of ic< o o o o 6«-1.5» depth

iTerage all ••r HI va VJI vo habitats n

- 45 - for sand bottom on the pressnos of current. This darter ooourrad mainly In the mid-summer collections. Normally, this species is difficult to net because of its habit of partially burrowing itself into sand;* however, in mid>summer it tends to move more.

This actlTlty seems to have been associated with its spawning season as evidenced by gravid females taken in mid-summer. The oollections at this season contalnei as many as 11 specimens.

This species is probably more abundant in the river than is indicated by its occurrences in the collections.

The other darters occurred only rarely in the river colle#-

# tions. The striped fantall darter was found to occur abundantly in the upper 5 miles of Bluff Creek. It did not occur in any^^ of the collections from other small streams and was taken onljr' once in the Des Moines. J-

C. Hourly and Seasonal Chainges in Habitat Usage

Large concentrations of minnows are often seen in the shallow quiet inlets in mid-summer along the Des Moines River*

In this habitat occurs a rich bottom microflora. The majority of the species found in this habitat during the day feed on these bottom forms. The July, 1946 seinin

Indicate an abundance of southwestern sanl shiners eund central bigmouth shiners in the inlets during the day euid the scarcity of spotfin shiners. The spotfin shiners movei into this shallow habitat at dusk and remained there throughout the night. Raise net samples in mld-strearo revealed the presence of the spotfin - 46

Table 6

ConparlsoA of night and day oollections of four speelss of minnows taken over shallow saud-graTel bars during late euruaar and fall.*

0^00-1^ 2000-0500 (17)** (17)

•3 OJS Speoies of Minnow • (Cyprinidae) • « IT A ! H X! P6 M M 1 M A • • "h < <

totropis d* deliolosus 27 0-2Mf 102 l*-521 rotropis spilopterus 10 0-56 1^ 0-133

'otropis d« dorsalis 6 0-16 15 0-95

PhenaoobiuE mirabills 2 0-9 12 0-^2 "All samples were taken with 20 toot alnnow seine. The eol- leetion dates were fron August 23 through November 19^* Bes Koines River. Dspth was 0 to l*^ fsst and some eurrsat was present. '"^Nuaber of eolleotio&s. - 47 • ahiners In aome numbers daring the day and their absence at night. Collections taken in late July, 1947, substantiated the

1946 findings on the diurnal and nocturnal habitat selection of the spotfin shiner. There is some tendency for the spotfin shin­ er to move inshore at dusk throughout the remainder of the summer and fall* Duxint^ the day, they are usually disj^ersed in deeper water and seldom occurred in large numbers in the collections.

Occasionally in the fall and sprint^, this shiner showed a ten­ dency to school in association with the northern common shiner and bluntnose minnow.

Durintg the spawnlnt^ period in early August, the southwestern sand shiner forms large schools in small limited areas in shallor water havin^^ a slight current anl sand bottom, not to be confused with inlets discussed above. In the fall this species is found

In larije concentrations in deep pools. The fall concentrations examined were mixed and contained as many as 14 species of minnows, dominated by the southwestern sand shiner. In late summer and fall, the southwestern sand shiners moved into shallow water over rubble bottom at dusk and they were accom­ panied with lesser nuiubers of spotfin shiners and central big- mouth shiners (Table 7). The suck:ermouth minnows also were found to move into shallower water over rubble bottom in the evening in association with the above-mentioned shiners. During the day, the suckermouth minnow often occurred with the speckled dace in the deeper water over rubble. The latter species was Table 7

CCfltparisoA of night and da7 ooUeotiona taken In inlets and nid-stream of three apeeies of BinaonB during Juljr, 19'<6,»

Inlet {12)** Inlet (6) Hid-Btream (6) Hid-stream (H) (O^OO-lltoO} (2000-0000) (0^00-1^0) (2000-0000)

• h • >4 • • h o • o c 0 A s s. d o, • ft ! spj: 1 S?5 Rang< « oi t of fiah haul Arerage Arerage of fish haul

Notropis spilopterus 7 2^49 73 24-IHI 27 oAj 1 0-2 GB Notropis d. delioiosus Ul 1-129 77 20-2^7 1 0-3 0 0

Notropis d, dorBalis 21 1-Uo 9 0-13 0.2 0-1 2 0-6

rent, sand-silt bottom; for mid-streaa samples the "raise-net" method was employed, depth 2 to 3 feet, current, sand-graTel bottosi. Samples were taken between July l6 and July 31t 1936> D** Hoines RiTer. *'^umber of eoUeotions. - 49 nerer found to show any tendency to move into shallotn water at dusk. In extremely low-water periods, the speckled dace was somewhat concentrated in the channel over gravel bottom.

In late fall large mixed concentr-tions com[.osed mainly of the bullhead minnow, bluntnoee minnow, and brassy minnow, were encountered in deep quiet yools. Such concentrations are found divorced from the dominatit southwestern sand shiner oon- csntr^tions described above. Except in the fall, concentrations of the bullhead minnow were liinitei to hij^h-water periods in late spring. Collectione at this period in the backwaters often contained over 300 specimens.

To verify the 1946 findin^js on movements of minnows, wire traps were uaei in the aprinti, summer, and fall of 1947. The traps were used on 24 days and were examinei at 1-to 2-hour intervals. The spotfln shiner, southwestern sand shiner, and

bullhead minnow were the only species taken abundantly. The activity of these fishes was almost wholely confined to the daylight hours, and often it was most pronounced just at dusk*

The activity at dusk may be correlated with the movement from

dee^. to shallow water.

D, Olscuaalon

The 22 species composing the minnow population (Figure 12)

in the Oes Moines River are not all confined to the river in their distribution. The central bigmouth shiner and ncithern 50

creek chub occur as pioneer fish in the headwaters of small,

tricKlingi prairie streams as well as in the river. The bull­ head minnow, common emftrald shiner, and river shiner are limited

to the river in their distribution. Several consecutive years

of unsuccessful sijawning in the river could extirpate these

species; whereas, a widely distributed species like the central

bigmouth shiner and common northern creek chub could soon

repopulate the river from its tributaries. The most abundant

species are not restricted to the river and could easily re­

establish themselves from tributaries 8ubse]uent to elimination

from the river. Some of tiie scarcer forms in the river also have

a wide distribution, and the fathead minnow and western black-

nose dace are found locally abundant in the smaller streams

t -OUi^h not abundant in the river.

The distribution of minnows in Boone County presents the

problem of the latent potentialities of rare species of minnows

in the river. Jrinnell (1922) discusses the potentialities of

rare birds in California. In California it was found that a

rare species of bird might become abundeuit as a result of

chanige in habitat to a more favorable environment. The occur­

rences of two rare species of minnows in the Des Moines River,

the spotted chub and the topeka shiner, possibly have such

latent possibilities. Two specimens of the spotted chub were

taken from the river in 1946. This chub was not found to occur

elsewhere in Boone County. It was learned, through a communique - 61 - from Mr. Harry M. Harrison, Jr., that this specisa occurs in the Boone River, a tributary of the Oes Moines lying to the north of Boone County. The single record of the topeka shiner from the river is discussed in the previous section. This species was fairly abundant in Beaver Creek, a tributary of the

Oes Moines. The records on both of these rare fish indicate thit they do occur in the river. At present, the environment is evidently not favorable for establishment; however, the reserve force exists in the form of populations in tributary streams. A change to a favorable environment in the river for one of these species might have a measurable effect on some of the other species now abundant in the river. In Beaver Creek, the spotfin sainer and southwestern sand shiner occurred with the topeka shiner. The bullhead minnow, which is an abundant

minnow in the river, was conspicuously absent from the collec­

tions in this creek. Also the speckled dace occurred in very

small ntunbers here as compared to the river. To the writer,

the delicate balance of conditions permitting the existence of species composing the mixed river population is of basic

importance in the understanding of population dynamics. A slight change in environment may bring about speoies change and fluctuations in abundance. Some of these fluctuations

will be discussed further in a later section. The rare species

are disregarded or considered by some fishery biologists as

unimportant parts of the fish population, and if the environ­

ment would remain the same, such reasoning would be Justified. - 58 -

In the two years of observatlonn made on the river, chanj^es occurrei in the abundance of two species (Table 16), To com- prs.ienl these potentialities, it appears aivlaable to approach tViO robleni of population analysis from a dynamic rather than a ^ * ' tic i-ers: ective.

Burton and Odum (1945:193) conclude from their study of stn&.ii floh in Virginia that

...of the various environment complexes considered, te'.'iperature, stream alz«, and gradient of flow appeared to be the idost Ira; ortant factors in determining distri­ bution within streams studied.

In Dooiie County, temperature associated with oxy^ien may be of

Importance to survival in the intermittent pools formed in late saimer in some of the smaller streams. The fish fauiia

In pools were mainly; central bigmouth shiner, northern cree c chub, northern coidinon shiner, central stoneroller, ani t le northern black bullhead. The lowest oxygen reading made in an Intermittent pool was 2,4 ppm., with a water temperature of F, and air of 880 Shelford (1937) mentions the

lariiness of the creeic chub (Semotilus atromaculatu^) in Sinall dry ini pools, and that moat fishes cannot survive such oonditiona. In California, Fry (1936) found a difference in

^rj>vth rate of Hesperoleucaa venustus isolated in intennlttent pools and in continuous strea

Des J-oines Hiver are probably not harly enough to maintain a population in the smaller creeks aa evidenced by their scarcity

In or absence from such streams. The physiological requirements of these fishes (spotfin shiner and southwestern sand shiner) are not known to the writer* but in handling minnows it was found that these two species succumbed more readily under crowded conditions and reiuced oxygen than did the two common species found in the small streams (central bigmouth shiner and northern creek chub). The inability of some species to withstand oxygen reduction (Allee 1912) and the crowded conditions in small intermittent pools is considered the important factor in limiting wide distribution of these species in Boone County. Trautman

(194<2) discusses tne importance of stream gradient in fish dis­ tribution and abundance. In 3oone Coiinty the steepest gradient was noted in the bluff-creeks and aere, as mentioned, the western blacknose dace, occurred. Otner txiaii in this type of stream, the streams were sluggish with a low stream gradient*

The factor of species intolerance has been discussed as a limiting factor for the fathead minnow.

In the next two sections, interspecific competition of the minnows for food and the dynamics of the mixed species population are discussed. - 54

VI. INTBRSPECinC COMPETITION FOR FOOD

OF THE DES MOINES RIVER MINNOWS

A. aancral

Throughout this study an attempt la made to present the

Interspecific relationships among 2Z species of minnona compos­ ing a mixed population la a mldwestern river. The preceding aeotlon sets forth the species composition and distribution of the mionows in Boone County and some of the possible factors

Involved in limiting distribution and use of various sized streams. In this section, food Is considered as a possible factor in determining the success of the minnows In the Des

Moines River. Competition for food may occur not only between individuals of the same species but also betvveen flah of dif­ ferent species. A very abundant species in the presence of a limited food supply would be confronted only with intraapec- ific competition; iiowever, a lar^^e population of mixed species encountering the same condition would be involved with inter- and intraspecifIc competition. Forbes (1914:3-4) states that

fishes have a common body of food resources of iaiscellaneouB character upon wiiict many of them draw almost indiscriminately accordinti to the circumstances at the time, but that from this com­ mon mass of resourceo, habits, and capacities there is a tendency to specialize in various direc­ tions, which tendency ^joes to its limit in soma species, halts at various Intermediate stages in others, and in still others is hardly discernible at all. - 55 -

Tha Tarious species in the Des jJoines River have followed the

pattern described by Forbes. Some have a very specialized diet*

others are partially specialised, whereas the southwestern sand

shiner la quite omnivorous. The sneoialized feeders have little

change in type of food through all the seasons. In the Des

Moines River these specialized feeders may be classified into

two groups. One type feeis on bottom ooze, and tha other on

dipterous larvae. The diets of tlie other minnows are modified

by seasonal chEin,ies and availability of foods. Several species

tend to select certain foods when a variety of foods are

abundant. The food habits of 13 species of minnows were studied, and

a few observations were also made on 6 less abundant species (Tables 10 through 14 and Appendices). To determine seasonal

trends in feeding, collections were taken regularly from April

9, 1946, through July 10, 1947. During the course of each week

in the sura;iier and fall of 1946, collections were taken so as to

cover each 4-hour period day and ni^jht. From these data the

feeding trends of the minnows could be determined.

B. Peeiing Trends

In a previous section it is mentioned that the minnows are

active during the daylight hours and are relatively inactive at

night. The total percentage of the estimated volume of food

items tends to decrease during the night, indicating little or no - 56 - feeding after dark. The volumetric determinations of food

Items In the apotfln shiner* based on 457 specimens taken at

various times of day and night durln,.j the summer of 1946, indicate an increase in feeding through the day, reachlnej a

maximum by late afternoon and (Tahl-: 8). The decrease

in volume in the ni.^ht collection:: t-js tliut this species does little feedintj at nijjht. The /oi i,metric data Included

in the appendices for the other species Indicate a similar trend. The fall data are also Indicative that the river minnows are mainly diurnal feeders (Appendices). The activity of the

minnows determine! by trappinfj and seining seems to correspond

with the diurnal feeling trend.

Bajkov (1935) mentions that our knowledije regarding the daily conrsumption of fiah under natural conditions is still very meager. No attempt was made in this study to determine the exact food consumption; however, the data do indicate that the Mianows feed daily and that the rate of digestion is quite rapid iAring the warmer months. Rlclcer (1946) summari2es the literature on the rate of feeding of fishes in relation to teiapoi^-ture and st-itss that for the few species of fishes that have been studied, there appeare) to be an optimal range correl­ ated witli summer temperatures in the natural habitat. The percent­ age of total volume of the various species of minnows was lowest in winter and spring. The water temperatures in the winter of

1946-47 at station 2 ranged from 32® to 35° F. The lower Table 8

Average percentage total volume of food items occurring at •arlous periods through- out day and nl^ht in Spotfin Shiner (Notropis spilopterus)i Dea Moines River, Saiimer, 1946.

Time 0600-1000 1000-1400 1400-1700 2000 0000 0400

No. collections 19 16 14 10 10

No. specimens 90 77 88 56 77 69

Percentage empty 9 8 2 11 S2 67

Average per cent total volume 13 17 19 26 14 •>56 " t«mp9raturea were accompanie) with a raduotlon in available fieh foods. In the winter there i^; a complete absence of terrestial insects and emerging aquatic insects in the Dee

Moines River. These insects did not appear in the minnows' diet until late April and early Way.

Hi^h-water sta^jes also affect the availability of food.

The quantity of food is reduced for bottom feeding minnows more than the surface feeders. During periods of hi

Fishes able to adapt themselves to surface feadin.3 were found to take terrestial invertebrates and plant materials.

On the Deg iAoines River the emergence of Ephemeroptara and Trichoptera seemed to be mainly In the late afternoon and duslc houra. An increase of those insects was note.I in the food of certain minnows collectedat duslc. Emer^jin^ Diptera were found in the dijestive tracts throughoit the day. The emergence of the subimago staje of Ephemeroptera, according to Needham,

Traver, and Hsu (1935), appears to be at different periods of the day for various species.

No noticeable differences were found in the feeding habits of minnows collected at the 3 principal stations established on the river. These data are combined and are presented in this manner tather than by individual station. 69 -

C. Principal Pood Items

The abundant foods of the minnows are classified in this study under broad headings to facilitate presentation. The same food types do not necessarily appear in the Des .lloines

River throuc^hout all seaoons and in Tables 10 throutsh 14, the food types are included only if they had occurred in large enough quantities to be considered important in the diet.

1. Plankton anl bottom microflora

Bailey and Harrison (1948) list the various insects common to the Des y.oinea River in r^oone County; however, they make little -nention of the bottom microflora and plankton. In con­ junction with the present investit^iitlon, a plejikton and micro­ flora study was conducted. A report of this study hnc been made elsewhere (Starrett and •atrick Ls.) £md will be discussed here only in relation to the Des Moines River fisheries. The various species of plankton and botto.-n microflora forms are listed in the appendices. Figure 13 shov;s the volumetric chanties in plankton in relation to viater level and temperature.

The true plankton of the Des ?/.oines is almost entirely composed of algae. The zooplankton is rather scarce in the river as compared to more sluggish and polluted streams (Kofoid 1908;

Allen 1920). Entoraostraca are almost entirely limited to late fall, winter, and early sprina and appearei regularly in the - 60 -

DESMOIwe^ EWEe PL/^MV^-TON STUD1E*=

N^LWHC.

A6I,' 4gpf' * pt; "ma.«. A.PI?: ' HA.V ' JuBI^IuCv " A.U<«

«Pf' «£T.' V4«v

Figure 13. Fluctuations of the Des Moines River plankton in relation to water temper­ ature and river stage during 1946 and 1947, Boone County, Iowa. - 61 - winter colleotiona when they composed 5 per cent of the plankton on the basis of count (Table 9). These organiama are taken rather frequently in winter by moat minnows. The central big- mouth ahiner seems to show more of a ureforence for entomoatraoa th^fi any of the other minnows. Ocoasionally a single oopepoda was noted in a summer plankton collection or in a minnow.

The food stuiiea indicate that phytoplankton is of little importance aa a direct food for the minnows. The apotfin shiner was founl to feed occasionally on phytoplankton in thn summer, this bein^ almost entirely Ijiicrocystis aerui^inoaa Kiitz. Insect larvae, especially Trichoptera larvae of the family 'lydropsy- chidae, are knovm to be plankton feeders (Ross 1944), and examination of several speci-nena from the Des ^'o.lnes aubstan- tiatse thia. The Mydropsychidae forn an important part of the summer diet of several species of minnows and through thia indirect way the plankton is of importance to the minnows.

The bottom "i.lcroflora or bottoir. ooze in the Des ;.'.oinea is an important food item for 4 species of minnows. The bottom ooze is comprised mainly of diatoms and is differentiated from plankton in the dl,i08tivs tract fay the presence of fine sand and, in some instances, mud. The volume of bottom ooze in the digestive tracts was found to decrease with a risintS river and to increase with a falling river. DurincS hijh water the bottom oo2e feeders containe 1 silt and mud with few to no diatoms. The bottom ooze feeders include: brassy minnow, bluntnoae minnow, fathead minnow, and central stoneroller. Table 9

Percentage abundance of varioue claaees of plankton organisms, Station 2, Dee Moines River

Blue-green Diatoms Green Entomos- Date (Myxophyceae) (Bacillaricae) (Chlorophyceae) traca Others

July 1946 43 40 15 2 August 1946 41 52 6 1 September 1946 14 75 9 2 October 1946 34 59 5 2 November 1946 16 82 « 2 December 1946- March 1947 4 88 * 5 2 April 1947 3 91 2 4 « May 1947 2 90 6 2 June 1947 26 67 7 « July 1947 45 39 14 e August 1947 48 33 14 5

^Lees than one per cent. 63

No pabliahei records on the food habits of the braeey minnow were located. This species has a long intestine simi­ lar to the other bottom ooze feeders. From the river 34 speci­ mens of brassy minnows nere examinel, of which 31 contained bottom ooze and the remainder were empty. The specimens of fathead minnons examined contained only bottom ooze. Coyls

(1930) in Ohio found that this minnow also takes some small aquatic insects. A specimen collected from a small tributary stream of the river containe 1 dipterous larvae and no bottom ooze. The 20 specimens of the central stoneroller examined contained mainly bottom ooze. This species was found by

Kraatz (1923) in Ohio to be chiefly a bottom feeder with diatoms as a preponderant part of the diet. In the Oes Moines

River, the bluntnose minnow was detsrmined to be largely a bottom ooze feeder; however. Its diet was found to be more varied than the other bottom ooze feeders. The specimens exarainel from the river tendei to Indicate that it is less of a general feeder he e than Kraatz (1928) found in Ohio. The variations in the diets of these species as found in other localities tend to indicate that they are able to vary their diet to a limited extent, dependlnjg; on the amount of bottom foods present. In addition to these 4 bottom ooze feelers, the southwestern sand shiner feeds to a considerable extent on bottom ooze as indicated in the accompanying tables. This species is quite omnivorous and seems to adjust its diet with Tabid

Conparisoa of food habit• of tha aora abundao'

BOttOR Plant Adult Adult & Water- TIphi OOB« naterial terrestial emerging boatnan opi insects Diptere (Corixidae) nyn 1 & & • d •Hk «r4CO i cB i 5 1 rH r4 rH 1-4 O o o o > • P- t» is la Spaoiaa of Minnow Is iH rH iH f-4 O ed xt CO (Cyprlnidae) • m A -H «0 •P *> a •a^ O •H W t t € o *•1 o a fish contain­ •p •p 4» fish contain­ •P ing itea ing itou ^ VL ^

Hotropis apilopterub 5 3 2k 2k 23 Itf 35 7 1 T*** 20

Hotropis d. dorsalis 31 6 2 10 5 Ik k 2 T 16

Hotropis cornutas Ik 3H 20 26 18 17 3 0 0 kl frontalis

Smotilus a* atro* naoulatus 0 0 i 2 17 3^ 17 7 0 0 17 Hotropis rubellas 15 15 5 1 15 15 15 5 3 10

Sztrarius aesti' •alia 0 0 0 0 0 0 22 5 0 0 •19

Fhanacobius airabilis l6 6 0 0 0 0 16 13 0 0 k

Oaratiehthys perspieaua 17 kl 0 0 0 0 17 5 0 0^ i

Hotropis d. deliciosus 50 66 11 2 9 3 11 1 1 T 22

^rborhynohUB notatus io 9^ 0 0 0 0 0 0 0 0 7 l^rbognathus hankinsonii 100 100 0 0 0 0 0 0 0 0 0

Caapostcoa ananalum pallum 100 100 0 0 0 0 0 0 0 0 0

Fiaephales p. proaelaa 100 100 0 0 0 0 0 0 0 0 0

*Fariod from 7une 27 through Sapteaber 18, 19^* CoUeotiona taken between OSOO aad 0*33^ f**^ ^0 2,9^ feet. ^Columns under heading "Aquatio n]mipha and larrae" include Xpheaeroptera nyapha, n^leh ***f aignifiea less than 0,5 ot one percent.

« a. 1 4 I ^ fish oo&taln« sow 1 o 6 o IS OK. s i: s; S ing itea h "B-Si B • v • M l\3 M * f o • o ON t: VJI P O !S H -P- ^ tot-;l volume H o o o o vo on ®v o on VO fish oontaln- H* >tH- ing item 51 rc % ^tal Tolua« o o o o VJI o o ra o s ing item 3lg 9® »tr I*c*^ I ro -n| VjJ ^ total Toluae to- ® IV} 8 n *#• t? o o o o\ O § ct t>l A > ^ fish contain­••a 9 o- o o o o M o o o s o M V?J •J t>' S £j ing Item i9 •i » PC» •i P »» to 0 in cr> "fi total TOlums o o o o ro o o o on o 1

m t» rx U » 1 o o o o m VJI VM on 6 Si Vil CTv % total TOltBBS • H •

) o I-" T 13 1 2 1 "H ( VH H lO No. fish szsB^ vn VJI ON £ s s 1 ined (\3 o "o 'o ro OIL H VJI Ml to VJI ro M Ko. fish enpty O % B M Gi G s 1 VJI s 1 § Ifo. oolleetions

\ei on vo on 1 OM on i3 ATsrass tolvmrn & & € la %

65 - ¥«U« U

Couparlaon of food liabita of tha aora alraadaBt

Botto Plant Adult Adult & Watar* Epta ooza auiterial tarraatial amergine boataaa opt insaeta Diptara (Corizidaa) nya

h i h i « 1 « i 0 1 (0 i o o O O c • § g • Is • Is > § s • n s Spaclao of Minnow O o •» O o O 4i iH r-H t4 •ri 1—( 'H (Cyprinidaa) o • e a +> t o ^ V*.

Notropia apllopterua 6 7 25 5 U9 ifi 16 9 5 k

Notropia d. doraelia kl k5 11 2 23 l4 39 16 1

Notropia oomutus frontalis 7 3»» 35 13 2 17 6 15 « saaotilua a* atro> maoulatua 5 2 5 5 U 2 5 T 16 19 5

Notropia ruballue 6 3 0 0 53 Ml 12 3 8 9 Eztrariua aasti- Talia 1 * 0 0 1 3 9 6 0 0 0 Fhanaoobiua nirabllia 17 u 0 0 0 0 lif 2 3 1 0

Caratichthya perapifuttt 20 69 k 2 13 2 % 2 0 g Notropia d. daliei^aaa 90 sk 1 5 1 i 1 5 1 1

HyborbTaetaiua notatua 100 100 0 0 0 0 0 0 0 0 0

Hjrbognathua bankinaonii 100 100 0 0 0 0 0 0 0 0 0

Caapoatoaa anotaaltia polluB 100 100 0 0 0 0 0 0 0 0 0

Piaaphalaa p. pronelaa 100 100 0 0 0 0 0 0 0 0 0 *Pariod froa Septeabar 19 throosh Voraabar 23, 19^ Oollaotiona vara takaa batwaaa frcn O.'ut faat to 1.20 faat*

FF M o o o o H M H o M 5g' VR % total TOlUB* a I g i • » cr ^ flah OQBtaln- 0 O N o o o o H O o o VO V3I *- I ? o a» p- ® 8 n B ga 5 (S o o o o o o o VX -P" ro ^ total volume •i o 1 0H* 01 ^ fieh contain­ o o o o o M VO o C\ V*l M •1 H" ing item 0 O M trO !i o o o o •4 M iei o no V«l M ^ total Toluna 5^ m I €»• % ->l % fiah contain­ o o o o OB. Ot. ON lO VM OK. Sa-a ing item SA eM 1

M M lO o o o o o \o 8^ NJI \3» \» ^ fiah oontainl: ! item » P' 1* • • O »> at. »» o o o lO ro H ^ total Tolune A* o ON ON s;

o o o o o o O o O a o o ^ fish contain­ 2 9 ing iten 8 H • H if • o o o o o o o o o o cr\ o o ^ total volume \M •P V 9 ^ total Tolune SPJT ) o o o o o) Vj4 \JI v3l •tr OH. 3 7 • B ? 5 7 • ( ( 5 o No. fish exaa- lO ro VO £ o a\ i s ined D —- fO No. fish empty "o "o o "o lO o\ V3I OS Ov IOi :3 • s «• 0 M M lO lO ra ro No. oolleetioni 1 lO ro vjn o\ -P- (-• VJ!

ro ro ATerage Tolome on vn —4 ir VJI v» M in i

66 -

Tabla 12

Cooipariton of food babits of th« aorc •btmdaAt

Bottm Plant Water- Ephemeropt- Triehop- oose aatei•ial bofititan era njrapbe tera (Corixidae} nyaphs

1 1 « 0 a A • i •H •H •H a i 1 CO a rH •H •P i •P rH§ o rH O rH e: O Spaeies of ninBowe • P-O > § a o O 1 i» % o • • O ( rH 1 rH (CTprinidae) h rH 44 i Xi ^ m xi in (B oa 4» ta •H 1 " w O o •H ec Vi 1 >o Vl ct •P +» fish contain­ 4> v« a € ing item

^ yi.

Hotropls apilopterua 0 0 2 1 k 27 2 g 6 6

Notropis d. dorsalis 2 1 0 0 2 1 5 9 l»t 25

Notropie oornutus frontalis 3 k T 12 22 20 50 l6 6

Seaotilue a. atramaoulatus 0 0 0 0 11 19 22 26 33 6 Notropis rubellus 0 0 0 0 0 0 Ik 9 0 0

Eztrarius aestivalis 0 0 0 0 0 0 0 0 3 16

FlienaoobiuB mirabilis 0 0 0 0 0 0 0 0 3 1

Ceratiehtbys perspiouus 0 0 5 Ik 10 3 0 0 10

Notropis d. delioiosus kl 65 0 0 0 0 3 2 6 10

Byborbynobus notatus 50 <7 0 0 0 0 0 0 0 0

Qjrbogaathus hankinaonil 75 100 0 0 0 0 0 0 0' 0 CeapostttiB anomalum puUtai 100 99 0 0 0 0 0 0 0 0 Piasphales p. proaelas 100 100 0 0 0 0 0 0 0 0

"Period from NoTcnber 2H, through Mareh 51* 19'^7* Collaotiosis taken bctwaan OflOO froa 0»k0 feet to 3.00 feet*

» C+ a M 0 ^ fish contain­ *i "a oooov>40oo!ir!o^ » V ing item a e* a 3 DT s • c tli ooooioooovo9>'iS i total TOlune tJ o 1 f B «» t-3 8 ViJ fciii ^ fiah contain- O SVM V*l O V>1 ON • H> •a V o r t ^ total volume ? ? o- O O O O O Ok. 6 ON O ON ON 7 ie*- . L CO r ' RJT & 'ft fish coutair.- C C H- 1 (» ro h; -F \o 3 " ^ o O VA O -<4 -p \ji es g ing item s 9 # • ? ro _ vjj *" ON ON % fish oontain- o vn o s s s $ ro ->i o H* B > a ing Item & Sll g H>VX-*ivO\0 Q ^ON OH OVJ4NJ< •troi.OlkOvOVTI ^ total ToluKe s

I OOOOOOOOOt-'-P' ^ fifth contain­ s ing item m tf o V>l • OOOOOOOOOH<->l % total voluoe 9

2 M to ^ fish contain­ <4 00 OOOOM3VJIOVJIO i ing item 1 H ooooio-r^orao H VJ* ^ total volume 9- So &

4 OOOOOVXMOOOO ^ total volume •B • »" S»* O H B «+ et i> o u fo No. fish exam­ vo VJI >s H* -P" O*. ON \j4 8 « ^ ^ Co ined

No. fish empty o o ro OQL V>l IV) ON -p- (V)

No. coileciions S -f oil ON ON ON V>4 *-^0*.VD •

NJI -<4 VJI lO tr*oak H Average volume in % 1

•i;

- 67 -

Tablff

Conparlson of food habits of the more almadask •!

Bottom Plant Adult Adult & Water- OOSfl Baterial tarrestlal emerging boatman inseota Diptera (CorixldB< -1— ti "iS B 'S ft I "ffl i p r-4 r-i (H O o o O §s Is p- > I s § s O 4» O -P Is o • O -P O 4» Sp«ei*s of Klnncw •H •w O 4* O P f-4 «d iHao •rf 0 (Cyprlnldae) 4» 09 « t)l3 o M ao •2 PO d € •p •p r* ft •p"8 C5 P p

Notropia bpilopterus 0 0 20 6 9 11 36 10 2 k 16

Notropia d. dorsal!e 0 0 21 7 0 5 0 k 7 i Notropia oornutua frontali a 0 0 65 63 10 2 5 1 15 12 10 SMiotilua a. atrona* oulatus 0 0 17 1 33 15 0 0 0 0 50

Notropia rubellua 0 0 2 0 9 62 6>» 0 0 0

Extrariua aeatlTalis 0 0 1 2 5 0 7 0 0 0

Hienacobiua mirabllia 0 0 k 2 0 0 17 10 0 0 0

Oeratiohtbya perapiouua 0 0 27 16 2 5 16 0 2 3 Ik 3 Notropia d. delioioaua 16 59 33 7 2 T 16 3 k 2 16 1 l^borhynohuB notatua 50 ^7 . 17 if 0 0 0 0 0 0 0 Hybognathua hankin- •onii 90 100 0 0 0 0 0 0 0 0 0 Campoatoaa anomalum puUuH 100 92 0 0 0 0 0 0 0 0 • Pimephalea p. promelaa 100 100 0 0 0 0 0 0 0 0 0 1947* CoUeotlona taken between 0000 and 2d0§» ug feet.

»« fish eoatalB ' ^ a w I = O On 4r O O 8 1. ia« it«B r a

33lt p o % total Toluna a h o o 8 ^ o o o VM f a i IS o a r o o i 9 r r a f

«»• T ^ fish aoataln< l 0 o o P 8 VM ON o o \JI lag itan R o o On Ok ->1 ON o o ON *- o ^ total •oluma 1 • H• a p % fiah oontala- >s o <^s.;s>ss^^o VJI lag Ita 'Ui 1 m 1 V7l lO ^ fiah oootain- t-* 0 > i:j >5!. >5" ^ >5 >S s M M iag itaa IIIa • lO % total YOlUM 2 O 9t. OIL ^ ^ ^ 3^ G *5* ns >i «»• o % fiah contain' •d O O O O O O O O o o ing itaa 8 ! •m £ o o o o o o o o o o % total Toluu

% fiah oontain* o o o o o o oa o ON NO ing itaa •- Hsr*u H 0* ,*>' a e o 8 5*^ o o O Ul O O O NA O Ul % total TOllOM ^ a a • -7 a a S O H H- o o M *• \J4 ^ H V«i to % total TOlUBW

8 s s* No. fiah axn- inad

o o 01. VO Vi> o M OIL OK. No. fiah •m.ptj o

No. eolleotiooa a CTN M M M^OIlOOnVDON vo vo 9^ VJI oa Avaraga Toluma vSv CT\ \ji 4r ^ On injt

5 o M I •* Si t 8 »< *i »< a • s »-»•» & s » ,1 3 0 \09 H- •§ n •d :3? O • » t I o t* M <* »* H» •a ^ • §• p c e H- M> » • t3 O :g^: B r-o Q* •* •% 9 m 2 •o a •d m er H» •i D* M S ^ m » (*' • g >1 C3 1 i & 1 S t S t p.- an i o § fli g » sill m i

SMI V0 ON ^ flah eoBtala- 1B« ItM g|

l H a

i M s «s •

• H ^ r 9^ t •H 8 o o o o o ^ total TOlUM a <4 O n t a a l • P o o o oi a M U?M ^ flah coataln* lug ItM

M :l o o ra O M >5 Vj< V>4 5( total Toloao V>1 M o o O 1 'ft total volume e o O V>l O ON VJ) ::ei OSl l-<0 H t) g 5» t-' 3 P- ^ fisil contain­ "O ® C ^!i o o o o a\ o .p- o VO cr •i t-" ing it en O t* **• J »i H- » S »» cn §s o o o o o ->i o ro ^ total voim ie

^ or •s; VtJ o o o -r o o VA o o o % fish contain­ o 5g C4- 8 ing item • El? P* o vrf o o ^ e o o ^ total ToliiiLa flI IS • mm ^ flah oontaln- Ky O M 1 I H* I o B c o « » O 9\ lojt it«a 1

M* 11 cr cr e VM o o o o o ^ total TOlUM ^ u g M li • n flk ^ flab oontaiA- 0 O M S I M I o o S ON o ^ o ON log it«A •5 • a H p* a M P M OB S A II •o ro ^ total volume ^ H s I o o O ff\ VJi o v» o ->« 1 1 i 1 ^ flah oontaln- srtl 1 o o 0^*0 00 0 o o VJ4 • 5. ing item 3 o 1 9 or 1 H AO 1 & B o o O Ok. o o o o o o to ^ total voltsns ­ a 1 v

r ** I 9 e a a l a VX H ^ fiah contain­ a O 1 o o O 4:" VjJ UJ Jtr O o O ing item s gU 9 -t? g ^ fish contain­ B •< .a M ON \»l V*l ^ B C 0 o o O CN VO ->l Vj4 \j4 NO ing itea ^ 10 l» a ai er c«- • • H- tV3 H o o o OS vn v>i ^ 'S NO ^ total VOlUI46

fO VM _ ii fiah contain­ — w o o O O lO o o o o o ing item Hg« IIC p" •J * H- O 4^ Oik. o o o o ro -4 o o o o o ^ total volume S 3 I I I * • * O • » i O «b VX 4=- ^ o g!. VH s ^ total voluae »e • ? ' H H M V ro •«-» CJ No. fish exan- ro M O O ro Vjl M VM ON lO inad

No. fish empty a

O M VP Ov ON O Ml '^• M t a

? D

lO —4 V*t 0\ to ON 0*. No. collections VJI 9 Avaraga voluna Vd on ON ON *r vn !r in fL

- 69

saasonal availability of food. In the fall, the decrease iH

available Sphemeroptera nymphs and Trichoptera larva* was

supplemented by the southwestern sand shiner with bottom ooze.

The ability of this shiner to use foods is a ponaible contrib-

utinj^ factor to its success in an environment subjected to

severe changes. This adaptability is further shown in its

food habits during hijh water. In the absence or scarcity of

true bottom ooze at high-water sta^ea» this shiner made use

of the available plant material, terrestial invertebrates• and

aqttatic insects.

Bottom ooze waa found to be the chief food ite/n taKen by *

fry of the southwestern sand shiner, bulihe.d minnow, blunt-

nose minnow, and river carp-sucker (Carpiodes bpp.). The fry

of these species are ^jresent in August and September when the

bottom ooze is usually rich in diatoms. In the following

section, the spawning seasons of the various minnows are pre­

sented; however, it should be stated he. e that the central

atoneroller and tho brassy minnow are early spawners and their

poor success in the river may* be associated with the reduced

bottom microflora when the fry are seeking food.

2. Plant material.

The food class here designated as plant material does not

include phytoplankton and bottom ooze. The following plant

materials were taken most frequently by the Des Uoines River - 70 - minnows: Sallx ap» erobryoe, Tarious seeds* and filamentous algas. The Salix embryos are available only in early summer and are fei on by all but the bottom ooze feeders. During this period* 61 per cent of the apotfin shiners, excluding 0400 col­ lections, contained Salix embryos which amounted to 53 per cent of the total volume of food. The other apecies of minnows tended to feed on the Salix embryos in lesser quantities. Thess

Salix erabryoG served to supplement the diminished available food supply throutih the high-water periods in early summer of 1946 and 1947.

Filamentous algae are only occasionally taken by most minnows. The northern common shiner was found to contain more filamentous algas t an any of the other ninnows, largely in the summer and fall. Filaments of Cladophora epp. were the most frequent genus of algae in the fish examined. The filamentous al^ae in the river are found attached to rocks and sticks, and in this habitat t ere are several species of Heptageniidae and

Bftstidae nymphs. In some instances, the algae in the fish may have been invested accidentally while feedinij on t.ieae nymphs.

Seeds occurred regularly in the bullhead minnow and only occasionaly in the other minnows. In the fall of 1946, a slight rise in water level covered some of the previous season's growth of Eragrost is sp., Amaranthus and Cyperus sp. Seeds, mainly of Era.^rost is. formed 69 per cent of the total volume of the bullhead minnow's fall diet. Other species of minnows - 71 oollected with the bullhead minnow, including the spotfin shiner, southwestern sand shiner, bluntnose minnow, central bigmouth shiner, and northern common shiner, were seldom found to have taicen seeds. The bullhead minnow in this instance was aelectiv* in its feeiin^ and was found to take seeds whenever available in other seasons.

Terrestial invertebrates.

Miniiows faei upon terrestial insects belonjing to the following oriers: Orthoptera, Neuroptera, 'lampitera, Homop- tera, Coleoptera, and '^ymenoptera. The various families are

included in tho appendices with the food occurrences of the

various minnows. Neta were not set in this study as described

by Needham (1928) to determiao the amount of "drift" food; however, fieli observitions indicated em Increase in abundance of this food in the presence of a wind and in the autumn. The

VBi^etatIon, particularly overhanijinj trees, is undoubtedly an

important source of this supply of food. The small adult

terrestial insects .vero taken more by the minnows in the fall

than at other seasons. The s.^otfin shiner, rosyface shiner,

central biismouth shiner, and northern common ahiner tend to

feed at and near tho surface more than the other conmon minnows.

The increased feeding on terrestial insects in the fall seems to

be associated with the abundance of these insects and with the reduction of ^phemeroptera nymphs and Trichoptera larvae. - 72 -

Terrestlal insects, particularly Coleoptera, are of some iraportanoe In late spring and aarly auraraer hi^^h-water periods.

Even the aiuatic larvae feeder, the speckled dace, occasionally took a small adult terrestial Insect durin.j hi^jh water.

Terrestial Coleoptera and Lepidoptera larvae are taken by the minnows when available to them, as was fo'ind in the spring of 1947. For a period of a few days, LeiDidoptera larvas of the family ?halaenidae appe -red In the diet of 4 species of minnows. Those larvae constituted a main part of their diet while available. In iii^h water terrestial larvae ars taken In the backwaters. Also soine species of minnows take earthworras over the flooded land. These items mi^ht be considered as

8U;jpleraentary food items iurinj some periods of adverse eonditions.

Aggatic nymphs and larvas.

Throuihout the yaar, aquatic nymphs and larvae form an itnportaiit part of the diet of those Des Moines River minnows which are not strictly bottom ooze feeders. The Kphemeroptera nymphs and Trichoptera larvae corapriae much of the summer diet.

A reduction in volume of this fauna is eXj..)eoted following the emergence of the larger forms through the summer months. This reduction was not only refLaoted in the ilet of the minnows but

In the bottom samples aa well. The small size of the youni oymphs makes them rather Inacosasible for most of the minnows. 73 -

Botti the fosaorial and sprawlinj types of Ephameridae iiyrapha are taken by the minnows In the aumraer. The genus Sphoron was almost limited to the summer diet. This foasorial type nyraph appeared to be talcen by the minnows Just prior to its trans- forraution to the subima^o sta^e. The sprawl in^j type nymph

Potaraanthus occasionally occurred in the diet throujhout the year* The Hepta^eniidae and Daetidae nymphs were found in the minnows at all seasons. The ejenus otenonema appeared to be the most abundant of the family Meptu^eniidae of mayfly nymphs in the river and occurred more frequently in the minnows. In the fajnily Baetidae, Baetisca and Blasturus were rather abun­ dant in the rivor but occurred rather infre.juently in the diet.

The fa.aily Hydropsychidae was the comiaon fona of Trichop- tora larvae taken by the lainnows in the sa-rimer of 1946. These larvae are found in the river attached to stones and sticks in the presence of current. In swifter waters they are often associated with the larvae of Siaulidae. The Trichoptora larvae formed oiily a siaull part of the minnows* diet in the fall, winter* and spring.

In the Dos uloinea River, various dipterous larvae are available as food to fluhes throuf^hout most of the year. The

Tendipedidae (Ghironomidae)« Tipulidae and Ephydridae are the most important dipterous larvae. Simulidae were seldom taken by the minnows and appeared to be of more importance to the darters, which feed in the swifter water. The availability of - 74 -

lanrat tends to be lessened during periods of high water as is

clearly evidenced by Table 14. Their small size and more rapid

rate at which they are digested (Raney anl iVebster 1940) con­

duces one to minimize their importance as a fiah food. They

form an important part of the annual diets of the apeckled dace

and suckermouth minnow. Dipterous larvae were found to comprise

much of the diet of yount^ spotfin shiners and northern common

shiners. The other minnows took dipterous larvae in numbers

only during the winter. In winter and early aprin^i these larvatt

formed a large percentage of the diet of 10 of the common minnows

based on occurrence rather than volume. Breder and Crawford

(1928) found th&t Notropia cornutus in the Oxun River, D. C.,

fed more on Ephemeroptera and Plecoptera nymphs during the

winter than other parts of the year. The northern common shiner

(Notropis cornutus frontalis) in the Dee "vloines River was found

to increase ^jreatly its diet on dipterous larvae during the

winter. Some Ephemeroptera and Flecoptera nymphs were taken in

winter, however, in lesser quantities than in summer.

It is doubtful that the increased feeling on dipterous

larvae in the winter of 1946-47 by 10 species of the common

minnows resulted in severe intra- and interspecific competition.

No quantitative bottom sa.nples were taken in the winter; how­

ever, inspection of sticks and rubble indicated a fairly

abundant popjllation of dipterous larvae. Also it appears that

if the dipterous larvae had been depleted through the earlier - 75 - part of the wintert these forms would not have continued to comprls* a large percentage of the diet on up Into the early spring. Other aquatic nymphs and larTae, bottom ooze* and entomostraca were precent and serred as supplementary foods.

Plecoptera nymphs were occasionally taken by minnows.

Taeniopteryx maura (Pictet) nymphs are a part of the Des

Moines River winter fauna, and are sometiraea fed upon by the minnows. The smaller nymphal forms of Acroneuria spp. occurred infrequently in the minnows at other seasons. The large size of many of the Hecoptera nymphs prevents moat of the minnows from taking them. This order of insects may be considered of little Importance to the minnows.

Other nymphs were seldom seen In the Des Ir'ioines River and were rarely taken by minnows.

5. Adult and emerging Diptera.

The adult .nd emerging Diptera are an important food of the spotfin ahiner and central bigmouth shiner in the fall. These fishes appear to feel more at the surface in the fall than in other seasons. This ia further evidenced by the increase in terrestial insects in their diet tliroug;i this season. The rosyface shiner also followei this trend.

0. Discussion

It is of some interest to compare the feeding trends of - 76 - th« spotfin aHlner an.i southwestern sand shiner* the two most abundant species of minnows in the river (Figure 14). The competition, if any, between these two species appears to be quite limited in the presence of many food items. In the summer, these two species as well as others feed on aquatic nymphs and larvae; however, through this season there were other available or supplementary food itexs, such as terreetial insects, emerginj and adult Diptera, bottom ooze, filamentous algae, ani alult aquatic insects. In the winter the spotfin shiner and south^vestern sand shiner fed to a larije extent on dipterous larvae. As stated above, this was a co^nmon trend for most of tne minnows. In vdnter some comi^etltlon among species mii^ht exii^t for dipterous larvae, particularly if the environment had been unfavorable to dipterous production the preceding year. The absence of terrestial insects and emer­ ging aquatic insects in the winter reduces the amount of available supplementary foods. The spotfin shiner and south­ western sand shiner were able in the fall of 1946 to compensate for the shortBi^e of aquatic nymphs and larvae In their diets with other foods. The spotfin shiner did this with terrestial insects and emerjiing and adult Diptera, whereas the southwest­ ern sand shiner increased its feedirigon bottom ooze. It is difficult to establish definite interspecific competition of fishes for food. La^^ler (1944:213), in discussing this problem* states that The mere fact that two or more species feed upon the same organism or group of organisms cannot be taken as direct STidence that an evil exists. Por if the food item is abundant it is possible that the feeding could have little effect on the supply.

In the cpsao of the two abundant shiners in the river, it is doubtful If severe Interspecific competition exists except possibly in the winter and early spring. A true evaluation of thle competition is difficult to make in view of La.^ler's statement. From the data on these two minnows, the writer is led to believe that these fish tend to chan^^e their diet to other abundant foods when available rather than enter into competition.

Only three species of minnows had eaten fish. The river shiner preys on minnows to some extent in the fall. This speciss was rather scarce in the river, and it is doubtful that its predatlon hid any effect on the population. The northern common shiner and the northern creek chub in summer fed largely upon aquatic nymphs and larvae, plant material, and adult ter- restlal Insects. The northern common shiner also ate bottom ooze, an Item which was not taken by the chub. With the fall decre ise in .i^uatic nymphs and larvae, both species started eating minnows. The availability of minnows was much greater in the fall of 1946 t iSui In the precedin^i summer. The abundanoa of youn^ 3outhv;et3tern sand shiners, coupled with their tendency to form larje concentrations in the fall, perhaps made them quite vulnerable to the larger minnows and other fishes. The - 78 -

BOTTOM OOZE

SUMMER FALL WINTER SPRING HIGH-WATER

AQUATIC NYMPHS AND LARVAE

SUMMER WINTER SPRING WTER

ADULT TERRESTIAL INSECTS

SUMMER FALL WINTER SPRING HIGH-WATER

ADULT ArJD EMERGING DIPTERA

SUMMER FALL WINTER SPRING HIGH-WATER

PLAfiT MATERIAL

SUMMER FALL WINTER SPRING HIGH-WATER SEASON

NOTROPIS SPlLO^^TERUS •NOTROPiS D OELICIOSUS

Figure 14. Comparison of seasonal food habits of the Spotfin Shiner (Notropis spilopterus) and the Southwestern Sand Shiner (Notropis d. delicioaus) in the Des Moines River during 1946 and 1947. 79 -

oommon shiner made up part of this fall decrease in aquatic

insects by talcing more bottom ooze, but not the chub. In the

fall, bottom ooze amoLinted to 2 per cent of total food volume

in the northern creelc chub as compared to 34 per cent in the

northern co.nmon shiner. The northern creec chub's diet in

the fall became mostly minnows amounting to 70 per cent of the

volume. It appears that the aquatic nymphs and larvae are poss­

ibly buffers for the smaller minnows In late summer. In winter

some predation existed on the s:naller minnows by the northern

creek: chub and northern common shiner. In the spring of 1947

the northern common shiner's diet was chiefly plant material

includint^ buds and alt^ae, and no specimens examined contained

minnows. The northern creek chub continued to prey on minnowe

in the spring.

The southern channel catfish is the only abundant large

predator fish in the river. Bailey and ilarrlson (1948) made

a detailed ^tudy of the food habits of this flfjh in the Des

Moines River, Boone County, Iowa. They found the food of the younj to be mainly dipterous larvae, with lesser amounts of

Ephemeroptera nymphs and Trlchoptera larvae. These food items

also make up a large part of the minnows' diet in summer. The

speckled dace and suckermouth minnow are mainly dipterous

larvae feeders and It appears that some competition might exist

among these strict feeders and the yo^ng catfish, particularly

if all 3 species were very abundant. - 80 -

Eph«m«ropt«ra nymphs and Trichoptora larvae were found by

Bailay and Harrison to ba taken more by the larger catfish.

The Insect feedin^j minnows* diet in summer was partially com­ prised of these aquatic nymphs (Table 10). The channel catfish appears to have a varied diet and apparently is able to change its feeding as certain food items become abundant or rare.

The ability of certain fishes to modify their diet to take abundant foods and to compensate for the absence of their usual food items is probably an important factor in the abundance of various species. The turbidity of the water and the scarcity of food make the hitjh-water st >ge a critical period for fish.

The scarcity of enturaostraca is considered by the writer as a limitinc^ factor to some species of fish in the river.

According to Bajkov (1932), one of the causes of great mortal­ ity of fry Is the lack of food, especially plankton organisms.

The pleuikton studies on the Des Moines River Indicate the scarcity of true plankton in late spring during high river stages. The fluctuating waters in the spring also tend to reduce the bottom microflora. The youn^j of yellow plkeperch are known to feel on entomostraca (Smith and :.!oyle 1945). Tha faw young of this species taken in the river in late May and early June were all empty. The scarcity of entomostraca in the river through this period appears to be a very important liinitlng factor to this fish. Other spring and early suramar

•pawners in the river may also be limited by the scarcity of 81 -

plankton for the fry and fingerlin^s. The western ^soldan shiner ooourrsd In only two Des bloines River oolleotions.

Accordint^ to ilubbs and Coopsr (1936), this species prefers

weeiy lakes. The Des Moines River may not provide the propsr

habitat for this shiner* as well as lacking entomostraoa. Tha

main food elsewhere for the iolien shiner is sntomostraca

(Pearse 1918; Sibley and Rimsky-Korsakoff 1931; Sibley 1932;

Moore 1933; and others). The common emerald shiner shows a

preference for lakes (Eddy and Surber 1947), and in Lake Srie,

Ewers (1933) fo'ind 2/3 of the volume of its sumraer food is

plankton crustacea. Forbes and Richardson (1920) in Illinois

found tnat it feeds on insects, al^^ae, minute fish, and ento­

mostraoa. This species, as mentioned in the preceding ssction,

occurs in only small numbers in the Des iAoines. Only 5 speci­

mens were examined and were found to contain aquatic nymphs and

larvae and terrestial insects. Perhaps the scarcity of ento­

mostraoa as food is unfavorable to the common emerald shiner.

In summary, the minnows in the Des Moines River may be

classed as specialized feeders and as general feeders. The

general feeders are capable of modifying their feedinti habits

and thus avoid serious competition, food may be a limiting

factor in the abundance of the specialized feeders and ^f the

fry and fingerlings of other species. - 82 -

VII. DYNAMICS OF A MIDWESTERN RIVER MINNOW POPULATION

In the section concerning distribution of the minnowst it

is stated that some species are more abundant in the Des r/ioines

River than In its tributary streams. Also some species have

restricted distributions, whereas others are abundant in sev­

eral habitats. The food studies of the river minnows indicated

that no serious interspecific competition for food existed

during; the course of this investigation. The absence or scar­ city of food at high-water stages for young fishes is considsrsd

as a limiting factor.

During the study, evidence was secure! which indicated that

the time of high-water stages in the river may be a controlling

factor in the abundance of minnows and possibly other species.

A markei difference in the species abundance of the minnow

population was noted in the course of this investigation, and

it is believed that this difference was correlated with water

stages.

A. Changes within the Mixed Population

The abundance of the minnows In this study was determined

on the basis of percentage of occurrence of a species in the

collections, including all a^e classes, as discussed in an

earlier section. The relative abundance of the various species - 83 -

Of minnows coraposinii the total population did not remain statlo through 1946 and 1947. The abundance of oertaln speclee ohanged ooneiderably durlnei this period.

Throughout the study, the apotfln shiner and southwestern sand shiner remained the two abundant species of minnows In the river (Table 16), but the relative abundance to each other ohanged. In the first and last periods of the investi^^ation, the spotfin shiner was more abundant than the southwestern sand shiner.

The speckled dace ai-^d bullhead minnow showed the greatest change in abundance. In the first period the Si.eclcled dace occurred in only 10 per cent of the collections in contrast to

73 per cent in the followin^i spring. The bullhead minnow raads a similar increase from 8 per cent in 1946 to 73 per cent In

1947.

The occurrence of the bluntnose minnow, northern common shiner, roayface shiner, and northern creek ohub increases in the collections subse^ient to August 15, 1946. The fathead minnow, central bigraouth shiner, and brassy minnow dii not make any siinificant changes iurini^ the two years. The other species were scarce both years and were not taken frequently enough to show any changes in their abundance.

B. Spawning Periods

The spawning periods of the minnows were determined by " 84 ••

Tabl* 16

P«riodle«l ehangca in peroeatagc of oootirranoe In tbe D«a Hoines Rirar •oUaetions of tha nora abvndont epaoiaa of mlnaoirs.

May 16 Aug. 1^ Maroh 2^ Aug. 15 to zo to to Aug. 1^ Dao. l4 Aug. 1^ NOT. 22 19^ 19^ 19't6 191^7

Moa of eollaetima (25H) (199) (lOi) (33)

Notropia apilopterua 76 66 M 97

Notropla d.^ delloioaua 62 71 93 i2 Notropia d. doraalla 56 65 52 Sztrariua aestivalis 10 57 73 70 Notropia oomutua fr(mtalia 30 37 92 Hyborliynolius aotatua 29 1*6 )>« 55

Garatiohthya parspiouua i 31 73 5^ Phanaeoblua nlrabllla 10 3» 21 27

Hybognathus hanlcinsonl 16 U 12 15

Finaphalas p* pronalaa 15 10 1^ 2**

Notropia rubellua 5 li 20 3

Saaotllua a. atronaoulatua k 12 11 3 - 85 -

•xamlnatlon of tha ^onadSt appttarance of the yovuitSt anal the literature. Turbidity of the water prerented makinti of direct obeenrations on spawning activities. Live specimens of the

•potfin shiner were hrou.jht into the laboratory for observa­ tions on spawning.

The minnows of the Des t'oinea Hiver may conveniently be broken into three general i^roapa on the basis of spawninj dates

The early a.^avmera are those that spawn in late sprint; and early aummor. In this group the followin^i species are included central atoneroller, western blacknose dace, hornyhead chub, comraon emerald shiner, northern creek chub, carp, brassy minnow silver chub, an! sucl^erraouth minnow. Iravii females of the central stoneroller ware taken in late :iay from the Des :'olnes

River; however, very few younij were observed. Too few speci­ mens of the western blacknose dace and hornyhead chub were examined to determine their spawnin^^ periods in the river, but, according to Hubbs ani Cooper (1936), these species are early spawners. The spawninj season of the common emerald shiner In the river is evidently early. A spent female was collected on

July 17, 1946. Forbes and Hichardson (1920) mention that

Wotropls atherinoides taken in Illinois from the middle of May to the first of June were greatly distended with eggs and were apparently about to spawn. Reighard (1910) in Michii^an found that the creek chub (Gemotilus atromaculatus) spawned from the latter part of April to July. A few young chubs were taken - 86 -

from the Dee Moines River in late July. The spaiming dates given by Heighard are probably applicable to the Des Moines

Hiver since gravid females were taken in late April. Carp

appeared to have spawned in the river durin^^ late May and

early June. Younti northern common shiners were taken both years in late July. The spawning of this speoies in the river

seems to occur from late June on up into the middle of July.

Accordin^g to Hankinson (1932), the common shiner in Michigan

spawns in the latter part of May into June. The brassy minnow

probably spavms in June, as evidenced by spent females. A few

spent females of the silver chub were taken in the middle of

June, 1946. No younj of this species were observed either year.

The suckermouth minnow appeared to have spawned in late June

and early July, 1946. No evidence of spawning was found in

1947.

Ths bluntnose minnow and the fathead minnow are placed in

the group termed intermittent spawners, or fish capable of

spawnint^ throughout the warmer months of the year. The spawn­

ing of the bluntnose minnow in ;

part of May to the latter part of August (Hubbs and Cooper,

1936) at water temperatures of about 70® F. In the Des Moines

River the successful spawning period is confined to late July

and August. At Fairport, Iowa, Markus (1934) found the spawn­

ing season of the fathead minnow to extend from May on into

the middle of August. The spawning season was not definitely - 87 -

established for this species in the Des Moines since too few

specimens were obtained. Females taken in June and July were

ripe.

The third group is the late spanners that spawn from lats

July through August. In the Des Moines River this includes the spotfin shiner, aouthvuestem sand 8hiner» central bigmouth

shiner* bullhead minnows* speckled dace* rosyface shiner, and

river shiner. The spotfin shiner was also found to spawn in

late July in l/tichigan (Hanklnaon 1930). A spent female of the

rosyface shiner was taken on July ^5, 1946. Prior to this

date, the females examined were ripe. Forbes and Richardson

(1920) state that in Illinois females of Notropis rubifrotv,

were ready to spawn in the latter part of May. The river shiner

possibly spawned as early as the middle of July, 1946; however,

too few specimens were examined to establisli a definite period.

One ripe female was taken August 15, 1946. Forbes and Richard­

son (19^0) mention that the breeding season of this species

(Notropis .le.lunus) is apparently late.

C. Discussion

The river stages recorded at the Boone Water Works between

1933 and 1947 are averaged emd presented graphically in Figure

15. The graph includes only the monthly averages during the

spawning seasons of the minnows. Through this 15-year period,

river stages averaged higher and for longer duration in May and - 88 - \

''''\ LEGEND \ \ \ \

1 \ 15 YEAR MONTHLY AVERAGE RIVER \

\ STAGES DES MOINES RIVER AT\ \ BOONE DAM (1933*47 INCL) \ • / \ 1945 MONTHLY AVERAGE \ ——1946 MONTHLY AVERAGE \ \ \

v.-

•• — •• ^ 1 — •• —

1 1 1 MAY JUNE JULY AUGUST SEPTEMBER N. SPILOPTERUS N.D. DELICIOSUS N.D. DORSALIS EXTRARIUS AESTIVALIS N. CORNUTUS FRONTALIS HYBORHYNCHUS NOTATUS | T C.PERSPICUUS PHENACOBIUS MIRABILIS HYBOGNATHUS HANKINSONI [ PIMEPHALES P. PROMELAS NOTROPIS RUBELLUS CAMPOSTOMA A. PULLUM SEMOTILUS A. ATROMACULATUS HYBOPSIS STOREIANUS N.A. ATHERINOIDES NOTROPIS BLENNIUS NOCOMIS BIGUTTATUS RHINIGHTHYS A. MELEAGRIS _L X MAY JUNE JULY AUGUST SEPTEMBER APPROXIMATE SPAWNING DATES

Figure 15. Comparison of the approximate spawn- int^ dates of the Des Moines River minnows with average river stages in Boone County, Iowa. • 69

June than any of the other months. The arerage tended to be lower in July and at tninlmum low ataxies in August and September.

The 1945 and 1946 river stages are plotted separately on the graph for comparison. In August, 1945, river stoges of over

1,49 feet occurred on 12 days and through August, 1946, river stages remained below the 15-year average. Further reference will be made to these contrasting months. A summary of the number of days in each month during the 15 years for which the river stage exceeded 1.49 feet are presented in Table 15. The river stage of 1.49 feet was selected arbitrarily to differ­ entiate between low- and high-water levels. Table 15 indicates that hifih '.vater occurs in August and September; however, euch ocouri^nces are not frequent as compared to Kay and June.

The immediate direct effect of high river stages on spawning was not observed. The success of spawning was estimated from the ocourrenoes of young in subsequent collections. The avail­ ability of food for young fishes is reduced by the increased turbidity, volume, and washing effect on bottom forms. The current possibly also washes downstream some eggs and fry of certain species. The lncrec.se in erosion silt and siltation no doubt has a harmful effect on the eggs, fry, and food supply.

Smith (1940), in discussing silt in relation to salmon and trout, states th t for these fishes silt may limit or entirely prevent successful reproduction and probably limits the food supply.

Ellis (19^6) demonstrated experimentally that layers of silt Table 15

Number of days on whloh river stage was over L.'T9 F^st for Kay through Septenber 1933"19^7, Dss Holass Rirer at Boone, Iowa.

iH >»u ^ TI\ Jt J ir\ 2? o\ .^9 2? 2? S? A 2? H A 2? 1 S 4 2?

May 6 0 0 5 19 2i 0 0 1 22 12 31 31 11 30 k

JOBS 2 k 18 2 li 0 0 22 23 li 30 30 21 30 2

July 0 10 0 0 20 0 0 H ik 29 u 6 21 3 23 5 1 «o August 23 0 0 0 3 12 0 6 0 ll» 25 0 12 0 0 o 1 Ssptember 12 0 0 7 0 23 0 0 6 21 5 0 0 0 0 9 - 91 - from i of an Inch to an inch producad a very high mortality

Araon^ freeh-water mussels. The change of environment by increaaei volume as well as the elimination of possible suit­ able spavminfi sites perhaps postpones spawning for some species. This could also result in absorption of and a disinclination in svawnini.

Bailey and Harrison (1948), in discussing the Des Moinos

River ani other moierate-sized to lar^e prairie rivers, state that they have some evidence to indicate that severe floods during the early an i mi idle smniaer result either in poor reproduction or low survival of younj fiah. The present invest ligation of the mixed species minnow population tends to substantiate Bailey and Harrison's observation. The scarcity of youn^ minnows subsequent to floods was noted in 1946 and

1947. However, during these years some species mere quite successful as manifested by fall collections (Tabls 16). These successful minnows were late and intermittent spawners (Figure

15).

The high-water stages usually come in Utty an J June, and, therefore, the early spawners are not successful in the rivor.

The northern cree!< chub, an early spawner, occurred muoh more abundantly in the small streams where the run-off is rapid and the water level tends to stabilize much faster than in the river. The spawning was successful both years in the araall streams. In ths river throUiih this period chiefly sub- adults Eind adults were taken. It appears then that the sub- - 92 - adults occurrlnti In the river were of Braall-stream origin and that the river population may be partially or wholly dependent upon this source for replenishment in unfavorable years.

The high-rlvor stages probably greatly reluce the high breeiintj potential of the carp, another early spawner. A life history study of the carp in the Dea Moines might show a cor­ relation of years of low-water levels during the spawning period withi iominant year classes. The effects of hiih-rlver stages on early summsr production of intermittent spawnars is not knovnn; hovvsver, the fact that they are a.Je to reproduce later in the season when the river stages viere low tends to explain why sone of these species are successful in the river. The successful bluntnose minnow in

1946 and 1947 produced itn youn^i in 1-ite July and August; whereaSf the fathead minnow which is also an intermittent spawner is not very succeasful in ths river. The possibility that thii5 species is limited by its low tolerance to other species is discussed in an earlier section.

The river carpsuckere(Carplodes sppi^ are a very success­ ful jroup of ducicers in the Dea i'oines River. The fry and young of those fishes occurred abundantly in July, 1946; however, very few were takan in 1947. The water levels remained high up into the middle of July in 1947 in contrast to low-water levels i)i 1946. Here again the succese of repro­ duction of a group of fishes seems to be very definitely - 93 - aaaoolatad with water leTela during the spawning season. This group of fishes is apparently an intermittent spawner. The examination of several ovaries revealed the presence of several size groups of eggsy indicating intermittent spawning as was found in the mud plctcerel (Esox vermiculatus) by Carbine (1944).

The ability of the carpsuckers to reproduce later in the season gives them a decided advantage over the other suckers which are known to be early spawners.

The late spawners are the most abuniant species in the river* and, therefore, it is possible to follow more closely the dynamics of their population. The speckled dace In the

Oes &toines River is a short-lived, late spawning fish and very few attain an age over 1.5 years. The spawning of this fish la therefore largely dependent upon the one-ye-olds. The abiindance of the 1946-year-clas8 of the speckled dace in the fall of that year is indicative of the ability of this species to produce a large spawn from a low population comprised mainly of one-yeur-old fish. Harrington (1944) found on the North

Atlantic fishinj grounds that an averaje the largest adult stocks of haddock (MelanO/^rammus ae.^lefinus) resulted in the anaallest production of young; whereas, the intermediate stocks were the most successful. Small adult stocks even produced better than the large. Herrington's explanation of this relationship for the haddock was that the large adults were cannibalistic and also were in competition with the young at one or more stages in their development. The saccsss of the . 94. low speckled dace poptilation in producing a large spawn in 1946

was associated with what appeared to be a favorable environment

for expansion. That is* the population was favorably low and the physical environment was suitable for apawnlntg and providing food for the young* producing as a result an Increased popula­ tion of the species. The favorably low population must be understood to include not only the spawning species but the existing total population. A satisfactory physical environ^ ment for production in the Dea .Voines Riverls considered by the

writer to be a river stage of 1.49 feet or less. This belitf is substantiated by the increased plankton and bottom micro­ flora production, lower turbidity of water associated with silt reduction, suid fish production. The early 1946 low population of speckled dace appears to be correlated with the high-water levels in August of 1945 (Figure 15), which evidently provided an unsuitable spawnino environment. Data are not available on the population size in the earlier part of that summer. In

August, 1947, the water was low and the physical environment appeared to be satisfactory; however, the production of the speckled dace was low as compared with the season of 1946.

The species was abundant in the summer of 1947, and it appears as though the numbers were high enough to produce an unfavor­ able environment for expansion.

The change in the abundance of the speckled dace de.aon- strates the rapid fluctuation that an individual species oan make within a mixed population. If a hlgh-rlver stage during the spawning season of a species Is an Important limitln,;^ factor

In the river, a change In the periods oT floodln^j would probably reverse the present ralnnow populations. Low water prevailing through May, June, and early July with high-water levels In

August would favor the early spawnars and ^revent successful spawning of the now abundant species. Within a few years of such conditions, a short-lived fish, llKe the specicled dace, would either be extirj^ated or reduced to an insignificant part of the mixed population; whereas, tho e^rly and intermittent apawners would become the abundant species.

The bullhead minnow, like the specicled daoe, appeared to have a spawning failure in 1945 followed by a successful one in 1946. This species attaiaa an age of five years; however, few over three years of age were taken from the Des Xoines.

The few specimens taken prior to the fall of 1946 were largely two-yeeur-old fish. The subsequent collections were comprised largely of fish of the year.

The abundance of the southwestern sand shiner pennltted a more thorough study of a longer-lived fish than was possible to do on the lesser abundant bullhead minnow. The 1944-year- class was as abundant or more so than the 1945-year-class in

1946 prior to spawning In August of that year (Figure 16).

The two-year-old fish, which were so abundant in 1946, were greatly reduced during the winter (1946-47) and the following early spring. It does not appear likely that predation would 96 - b« an Important factor in winter on the Dee Moines River since the only abuniant predator, the southern channel catfish, feeds at a miniraum in the winter (Bailey and Harrison 1948).

No major changes in water level occurred durin«3 this period eliminating any heavy losses through stranding. Food was evidently not a factor as only 11 per cent of the 73 fish ex­ amined for food were empty. During this period, no winter kills were noted or reported* resulting from oxygen deficiency.

The collapse of the two-year-olds of the southwestern sand shiner population appears to have been a result of natural mortality.

The small 1945-yecir-clas8 was also reduced during the winter of 1946-47. By Auiust, 1947, very few specimens of this year class appeared in the collections. Most of the southwest­ ern sand shiners collected in the summer and fall of 1947 were young of the year and one-year-old fish. In contrast to the

1946 collections which contained many two-year-old specimens.

The scarcity of the two-year-olds (1945-year-class) may be traced back to the low production of the southwestern aand shin­ er in the Au^juat of 1945. This low production in 1945 appears not only to be associated with the hit^h water in August, 1945, but also with another factor as discussed later, that being the possible lack of successful aje spawners. The spawning of this shiner was successful in 1946 but not very successful In 1947

(Figure 16). Low water prevailed in Aufjust, 1946, and August, - 97 -

(194 r. 1 JULY 31, !946 fvlAFt' 2®, 1947

(1945) (1944)

OCT 5, 1946 (1946)

945)

(1944) (1947)

(1946

b5 15 A'JDARD length '-n'r.i

Figure 16. Comparison of year classes of trie Southwestern Sand Shiner (Notropla deliciosus) in the Des Moines River from six selected collections taken in 1946 and 1947, - 98 -

1947, but there was a differenc* In the spawning fiah which

may have been correlated with the suceess of spawning. Most of the spawners in 1946 were two-year-olds and in 1947 they

were mainly one-year-old fish.

Table 17

Percsntage of Southwestern Sand Shiners (Motropis d. deliciosus) in each age class in fall, 1946 and 194T.

Year 0 fears 1 Year 2 Years

1946 70 13 16

1947 75 24 1

counts on several specimens for each a^je .jroup of the southwestern sand shiner were made ising the nethod described by

TJlrey, Risk, and Jiicott (1936). It /vaa found that a one-year-old

female in late July contiinel some 250 ejgs, two-year-olis,

1100, and three-year-olds, 1800 ejis. Spent females of one-year- old fish were taken in August, 1946 and 1947, indicating that they do spawn. The one-year-old fish in 1947 were approximately as abundant as the one- and two-year-olds combined in 1946. The

lower production in 1947 mi.iht be attributed to the scarcity of the more fecund two-year-old fiah. The three-year-old fish of this species were scarce both years.

The southwestern sand shiner population in April, 1948,

was found to be similar to that of 1946« bein^ characterized - 99 -

by an abundance of two-year-old fleh. The data on thie shiner

tends to indicate alternate successful spawning; years and a

dominant year cluss. Black (194 5) found that the mimic shiner

(Notropia v. volucellus) populjition of Shrlner Laice, Indiana,

was greatly reduced the second year of his investl^^ation, which

he attributel to an almost complete spawning failure. It is

Interestin,! to note that the two-year-old fish were nearly

absent the year of the suawnin,^ failure; however. Black makes

no mention of this as an important possible fictor in spawning.

The effect of hi^h water in August durinj the epawnina season

of the southwestern sand shiner in the presence of a dominant

one-year-a^e class such as probably was the case in 1945, as

indicated by the abundance of two-year-oli fish in subsequent

collections, was of lesu importance on the population t. an if

it had been in a year with a two-year dominant a^e class. An

unsuccessful spavming in 1946 would have had a drastic effect

on this species; whereas, in 1947 hi,-;h ?/ater or some other

unfavorable condition in Au^just would have had little effect.

In 1948 unfavorable spawning conditions would aave a serious

effect on the population do/ainatei by two-year-old fish, simi­

lar to the year 1946. The ability of a low population of

southwestern sand shiners to replenish itself was not observed

as it was for the jpeckled dace.

The late apawnin^ period of the southwestern sand shiner

seems to be the important factor to its suoceee in the Oee 100 -

Moines Hlver. The majority of other species are not able to

compete with this ehiner nd other late spawnera because of

their spawning failures earlier in the year. The writer is not able to furnish direct evidence of the apace factor in

mlnnovis; howeyer* it appears that under favorable conditions

for the early spawners^ their abundance could have a direct

effect on the late spanners. Also the abundance of the late

spawners in the subsequent sprinj could be of Importance in

reducing production of early spawnera In an otherwise favorable

environment.

The other lite spawning minnows had a somewhat similar

history to that described for the southwestern sand shiner.

In 1946, two-ysar-old central bigmouth shiners were abundant

in the river euid were rather scarce in 1947, similar to the

findint^s on the southwestenu sand shiner. The central bigmouth

shiner did not have as successful spawning seasons in 1946 or

1947 as it evidently did in 1944. Some evidence of a dominant

year class of this species was also noted in several of the

smaller streams surveyed.

The 1945-year-clas3 of the spotfln shiner did not seem to

be affected by the hi^^^h water in August as much as the specKled

dace and bullhead minnow; however, the 1944-year-class appeared

nearly as abundant as the 1945. The species lives to be five

years of a^e in the river and the first three year a^ie classes

appeared re^^ularly in the collections. In 1946, five-year«old 101 - fish (1941'-yaar-cla8s) were occasionally taken, whereas in 1947 only one five-year-ol1 (1942-yeai—class) occurred In the col­ lections. A review of the river sta^je iata for 1941 and 1942 reveals that the river was very low in leite July and Auj^uat in

1941 as compared to 1942, This possibly illustrates the effect of higher river atM^es on the abundance of year classes of the spotfin shiner in the .river.

So far we have been concerned largely with the effeot of the time of spawning, spawning population, high-river stages, and the availability of food upon the abundance of various minnows. : erhaps brief mention should be made of predatlon as a possible factor. According to Bailey and Harrison (1948), fish comprised 37 per cent of the adult southern channel cat­ fish diet in the Des Moines River. The spotfin shiner was found by these writers to comprise 43 per cent of the fish eaten by the catfish. The southwestern sand shiner comprised 17 per cent and tho bullhead minnow 10 per cent. These three minnows amounted to 70 per cent of the fish taken by the catfish.

Under adverse conditions, these same minnows could enter into severe competition for food with the smaller catfish, partic­ ularly for a^uatio nymphs and larvae.

The adult northern creek chub and northern common shiner prey on the smaller minnows, especially in the fall. The scarce river shiner also takes small minnows during this season.

The yellow pikeperch, northern smallmouth bass, flathead cat­ • lOS "•

fish, and the northern pike are not abundant enough in the

river to have much of an effect on the minnow population.

During tho winter of 1946-47, the speckled dace continued

to use the open channel at station 2 even though ice coTer was

available. As a result this minnow was possibly subjected to

aorae predation by aquatic birds. Several belted kin^ifishers

(Me;^aceryle alcyon alcyon) were noted in the vicinity of the

open Ciianxiei throujiliout the winter. Also a few American

aieriiansers (;.'er.:ua ..ier,4anser ainerlcanus) were observed on

several occasion on the o >en water. The other species of minnows

were chiefly confine! londer the ice where it appears that they

would be subject to lesa predation by the fish-eating birds

than in ice-free waters. IJo measurable effect was recorded on

the reduction of the speckled dace in this area by birds.

In this investigation, no evidence was found that would

indicate any effects of predation reducin.i the minnow popu­

lation. - 103 -

VIII. PIP-HERY MANAaFMENT ON THE DES MOIN^^S RIVER

In connection with the ecological study, certain observa­ tions were made which have a possible ^earint: u;;on river management. Although these observations were incidental to the main study, they are briefly diacussed at this time.

The Dee I.ioines F;lver is a constantly chan^in^ body of water. The t^r idient is a fairly constant factor, whereas the varied run-off from the watershed causes fluctuations in the water level, turbidity, ani richiieae of the water. A river fishery management program must, therefore, bo flexible enough to fit the ever-chun^inei environment.

k:oder;i tr^mds in conservation are toward lireater utiliza­ tion of the fishery resources r ither them mere ly preeerving a species (Westerman and Hazzard 1945). Mauiy fishing laws are bused upon the philosophy of preservation rather than utiliza­ tion (Eachmeyer 1946). Observations on the Des Moines P.iver indicate that it:j fishery resources are not beinj utilized most profitably. The carp, waich is one of the most abundant of the larger fishes in the river, is not utilise! to any threat extent; but it is permitted to occupy space in the pools, which could possibly be used by the southern channel catfish. The larj^er carp are often difficult to catch with a pole and line.

Present laws in Iowa prohibit the use of set lines, an effectiv# 104 - way to catch carp, north of Route U. 3. 30. In the writer's opinion, this law tends necessarily to protect the carp rather than the catfish, which it is intended to protect. The law in a difficult one to enforce, and some fishorraon continue to use the set lines re^^arlless of the law. -Ji^jintj. now prohibited by law, not only provides another effective way to procure carp but would also furnish excellent sport. Trapping of carp would also permit greater utilization,if properly controlled.

The carp is in the riv-r and tiie extirpation of it from the river by application of known laethods and ^^ear la not possible.

Therefore, it would be wise management to make use of the carp and profit by its presence.

The principal arjuments against set lines and gi.^,iing are that their uae woull en linger the game fish. Actually in the

Boone County area the ^aine fiah that are present, other than the southern channel catfish, are not bein<5 utilize I to a .jreat extent. The northern pike, yellow pikeperch, and northern emallmoith bass are not abundant in the river because of unfav­ orable environmental conditions. He.iiovai of these fishes by sport fishino or even would not be an important factor in their survival. The southern channel catfish is fairly important to the anjlers, and it might be advisable to continue to prohibit and trappins^j for this species.

Ade iUate rnanajo ..ent of the Des ?.:oine9 River should include plans to increase the fish production, fish production Is - 105 - reduced by the periodic flooding and by the eilt carried in the

water. Greater utilization of the fishery and recreational resources couli be made if the flow could be controlled to a

greater extent and if soil erosion on the watershed were reduced

These improvements can be made only by cooperative action over a

period of years. It will require the application of soil conser ration practice over the entire watershed. Habitat improvement

in the river is part of a much lart^er program of land use.

Certain other stream improvement practices might increase

the fish and fishing in local areas. Fish are limited in space

during low water because of the scarcity of deep pools in the

river. In Boone County much of the better fishing is directly

below the two lowhead dams at Fraser and at the Boone iVater

Works. The current below these dams is swift enough to keep

the channel free of silt and to provide long deep holes. In

the pools above the dams, silting is heavy and fishin,^ is

usually poor. Lowhead dams to improve fishing generally are

impractical because of the costs involved. Also dams interfere

with canoeing, a sport enjoyed by many on the Des Woines.

Deflectors would probably provide pools; however, silting,

change of the river channel, ice jams, and floods all present

problems that would have to be thoroughly considered before

installing deflectors. Observations made in tuis investiga­

tion indicate no shortage of fish food. The installation of

brush piles would provide more habitat for a-iuatic insects; - 106 - howevert the increase in fish food would not offset the damage to pools nhlch brush piles would cause by diverting the channel and silting. It does not, thereforst seem advisable to Install brush piles in the river.

It has been ;ointed out that in the Dea Moines River, the successful minnows are late spawners and that the present fauna of commercial and ^ame fishes in the river are mainly early

•pawners. It appears that if a strain of a desired species that would spawn in late July and early Aujuat vsere to be devel­ oped throu^a selection and breeding and introduced into the river, more natural reproduction would be assured. No experi­ ments alon.i this line were conducted in this investigation.

Hayford and Embody (193G} and Davis (1935) have had some success in selecting and breeding strains of trout for early spawning, faster growth, and higher breeding potentialities. These experiments indicate some of the possibilitiss in selective breeding of fish for a desired purpose.

The minnows are abundant in the river and it appears that no shortage of forage fishes exists. Periods of high water extending throughout several consecutive summers would have a drastic effect on the minnow production, as well as other fishes*

TJie smaller tributary streams would probably soon replenish the river breeding stock, and euiy policies of restocking the river with minnows should be discouraged. Continuous seining opera­ tions in the fall could have a reducing effect on a river - 107 - ainnow popttlation. Certain Bpecles* particularly the southwest- em sand shiner, bullhead minnow, brassy minnow, and the blunt- noee minnow, form large schools in the fall. It was found that even a 10-foot common-sense minnow seine was quite effective in talcing lar^e numbers of minnows during this season. This is an excellent time to sample a river minnow population with the least effort. Tear classes of the population can be determine! as well as the success of the preceding spawning season.

To commercial bait dealers the river offers little possi­ bilities. The abundant species in the river are usually not considered as good bait minnows. The northern ccnmon shiner and bluntnoae minnow are fairly abundant in the river, but the majority talcen usually are too small to be of much value as bait. The smaller streams in Boone County proviie minnow bait for many local fishermen and offer more possibilities for commercial development of minnows than the river. The northern creek chub is quite abundant in these streams and is considered an excellent bait minnow. - 108 -

IX. CONCLaSIONS

The relative abundance of the individual species of minnoim was found to fluctuate. A study of the minnow population indicates that the followinj factors are of particular import­ ance in controlling^ the abundance of the various species:

1. The scarcity of entomoatraca during late spring and

early summer.

2. High river-sta^jes during spawning season.

3. Absence or scarcity of habitats required by certain

species.

4. Several consecutive years of unfavorable spawning

to a short-lived fish.

5. Invironment not favorable for the Increase of a

species.

6« Absence or presence of a dominant spawning year

class.

7. The food studies indicate that probably no severe

competition for food existed among the various species

of minnows for food. The diversified feeding habits

and the ability of some to claange their diets and

take available food tends to reduce interspecific

competition for food. • 109 -

X. SUI4MARY

There are 52 apeclee of fishes knovm to occur In the

Dee Moines River, Boone County, Iowa. The southern channel catfish and carp are the only abundant food fishes in the riTer.

The noinber of specias of minnows was found to increase in Boone County with increased stream width. The hardiness of a species to withstand low oxygen and limitei space is considered as an Important factor in limiting the number of species in small streams subject to partial drying. Intoler­ ance to other species is believed to be eui important factor

in the local abuniance of the fathead minnow. Some species tend to have a United distribution because of ecological

preference. In the river, habitat preference varied among some species with li^jht intensity and season. The speckled

daoa reiiiained in the channel regardless of lijht and season.

Severe interspecific competition for food was not thought to exist arnoni the minnows durin^i the course of this investi­

gation. Some competition possibly existed in the winter of

1946-47 for dipterous larvae; however, it appears that other

corapensatin,j foods and diversified feedinj habita of the

minnows reduced the competition to a minimum.

The scarcity of entoraostraca during late spring and early - 110 summer Is believed to be a limiting factor to some fiahest including the yellow pUceperoh* ioldsn shiner* and common eraerald shiner.

The abunlant species of minnows in the Dee Uoinos River are late siJavnriers, which is correlated with low-river stags.

The river shiner appears to be a late spawner and no explana­ tion of its scarcity is given.

The total minnow population of the Des Moines Hiver is known to be corapoaed of 22 species. These species vary in

their abundance from rare to the most abundeuit fishes in the river. This population is dynamic and is subjected in Virying amounts to the deciraatin;^ factors, dependintj upon the indi'/id- ual species' requirement-3. Several consecutive years of low- river staces in tae spring and early summer followed by hi^h- river stages later in the aummor could have a serious effect on the present abundant species and would tend to favor greater production of the early spawners. Based on a 15-year average of river stages# there seems to be little possibility of such a condition continuing over a long period and the return of river stages to the average would again favor the now abundant species.

The total population of the minnows in the Des Moines River could remain 8oms.vhat constant with great changes in the abundance of its composite species. - Ill -

XI. LITERATURE CITED

Allee, n. C. 1912. An experimental analysis of the relation bet«e«n physiological states and rheotaxia in laopoda. ijotiir • Exp* Z>ool« f 13 a 2S9**344.

Allen, W. E. 19S0. A qttantitatiTe and statistical study of the plank- ton of the San Joaquin River and its tributaries in and near Stockton, California, in 1913. UniT. of Calif. Fub. 2ool., 22: 1-292.

Balleyt Reeve M. and Harry K. Harrison, Jr. 1948. Food habits of the Southern Channel Catfish, Ictalurua lacustrla punctatus. Trans. Amer. Fish. Soc. for 1945, 75 (In press).

Bajkov, A. D. 1932. Fish population and productivity of laKes. Trana. Amer. Fish. Soc. for 1932, 62: 307-316.

1935. How to estimate the daily food consumption of fish under natural conditions. Trans. Amer. Fish. Soc. for 1935, 65; 208-289.

Black, John 0. 1945. Natural history of the Northern Mimic Shiner (Notropia volucellus volucellua) Cope. Inveat. of Indiana Lakes and Streams, 8; 450-469.

Breder, C. M., Jr. and D. R. Crawford 1922. The food of certain minnows. A study of the season­ al dietary cycle of six Cyprinoids with especial reference to fish culture. Zoolo^ica, Sci. Contr. N. Y. Zool. Soc., 2; 287-327.

Burton, Jeorge .V. and Eugene P. Odum 1945. The distribution of stream fish in the vicinity of Mountain Lake, Virginia. Ecology, 26: 182-194.

Call, R. Ellsworth 1892. The fishes of the Oes L!oines 5asin. Froc. Iowa Acad. Sci. for 1890-91, Part I: 43-56. - 112

Carbine, William 7. 1944. Egg production of th« Northern Pike, Esox luciua L.t and the peroentage survival of egisa and young on the spaiminci grounds. Papers <^Jilch. Acad. Soi. Arts and Letters for 1943, 29; 123-137,

Corastook, John Henry 1947. An introduction to entomology, 9th Rev, Tild. 1064 pp. Comatoclc Publishinjj Co.

Cox, Ulysses 0, 1896, A report upon the fiahes of southwestern Minnesota. Kept. U. S. Fish. Comm., 1894: 605-616.

Coyle, Elizabeth E. 1930. The al^ial food of Pimep^les promelas (Fathead Klnnow). Ohio Jour. Sci., iO; 23-35*

Davis, H. S. 1935. Improvement of trout brood stock of trout. Prog. Fi3h. Cult., 13: 1-6.

Dice, Lee R. 1945. Measures of the amount of ecologic association between species. i:colo,iy, 26: 297-302,

Eddy, Samuel and Thaddeus Surbor 1947. Northern fishes with special reference to the Upper Mississippi Valley. Rev. Ed. 276 pp. Univ. Minn. Press.

Ellis, M. M, 1936, Erosion silt as a factor in aquatic environments. Ecology, 17: 29-4/5,

Eechmeyer, R. w. 1946. Have vre over overregulated our sport fishery? 11 pp. 36th Conv. Int. Assoc. (Jams, Fish and Conserv. Coram.

Ewers, L. A. 1933. Summary report of the crustacea used as food by the fishes of the western end of Lake Erie. Trans. Amer. Fish. Soc. for 1933, 63: 379-390.

Forbes, Stephen A. 1914. Fresh water fishes and their ecolog/. 19 pp. Ill, State Lab, Nat. Hist, - 113

and Robart E. Richardson 1920. The fishes of Illinois. 2nd Ed. 357 pp. 111. Nat. Hist. Surv.

Prison, Theodore H. 1935. The stoneflies, or Pleooptera, of Illinois. 111. Nat. "list, surv., 20: 281-471.

1942. Studies of North American Plecoptera. 111. Nat. Hist. Surv., 82: 235-355.

Frost, Winifrei E. 1944. The natural history of the minnow, (Fhoxinus phoxinus). Jour. Anim. Ecol., 12: 139-162.

Fry, Donald h:., Jr. 1936. Life history of Hesperoleuous venustus Snyder Calif. Fish and 3£une, 22: 65-96.

Orinnell, Joseph 1922. The role of the "accidental". Auk, 39: 373-380.

Hankinson, T. L. 1930. Breeding bebavior of the SilverfJ.n minnow, Notropis whipplil spilopterus (Cope). Copeia, 1930: 73-74.

1^32. OlissrTations on the breeding behavior and habitats of fishes in Southern Michigan, papers Mich. Aoa4. Sci., Arts and Letters for 1931, 15: 411-425.

Haskell, David C. 1940. An electrical method of collecting fish. Trans. Amer. Fish. Soc. for 1939, 69: 210-215.

Hay ford, C. 0. and Gr. C. Embody 1930. Further prot^ress in the selective breeiing of brook trout at the New Jersey State hatchery. Trans. Amer. Fish. Soc. for 1930, 60: 109-113.

Harrington, v/illiam C. 1944. Factors controlling population size. Trans. 9th N. Amer. Wildlife Conf. x'or 1944: 250-263.

Hubbs, Carl L. 1926. A check-list of the fishes of the areat Lakes and tributary waters, with nomenclatorial notes and analytical keys. I>U8C. Pub. Mus. Zool. Univ. Kich., 15: 1-77. 114 -

______and John D. Black 1947. Revision of Ceratichthye a genua of American Cyprinid fishes. Misc. Pub. Mus. Zool. Univ. Mich., 66: 1-56.

and Oerald P. Cooper TSTe. Minnows of Michigan. 95 pp. Cranbrook Inst. Sci. Bui. 26.

and K. F. Lotiler "1^7. Fishes of the Oreat Lakes region. 186 pp. Cranbrook Inat. Scl. Bui. 26.

and A. I. Ortenbur^er 1929. Further notes on the fiahea of Oklahoma with descrip­ tions of new a^ecies of Cyprinldae. Pub. Univ. Okla. Biol. yurv., 1: 15-43.

and Boyd v.. f.alkcr 1942. Habitat and breeding behavior of the American Cypri- nid fish Notropls lon,^iroatrla. Copoia, 1942; 101- 104.

Jordauif D. S. and S. £. Meek 1885. List of fiiBhes collected in Iowa and f'isaouri in August 1884, with lescriptions of three new species. Proc. u. S. flat. ;.'U8., 8: 1-17.

1929. Kanual of the vertebrate animals of the northeastern United States. 446 pp. World Book Co.

Kofoid, C. A. 1903. The plankton of the Illinois River, 1894-1899, with introductory notea upon the hydrography of the Illinois River and its basin. Part I. iuantitative investigations

TWS. The plankton of the Illinois River, 1894-1899, with introductory notea upon the hydrography of the Illinois River and its basin. Fart II. Constitu­ ent organisms and their seasonal distribution. 111. State Lab. Nat. Hist., 8: 1-354.

Kraatz, Walter C. 1923. A study of the food of the minnow (Campostoma anoraalum). Ohio Jour. Sci., 23: 265-883, 115 -

1928. Study of the food of the Blunt-nosad l^linnow* Plmt- phalas notatua* Ohio Jour. 3ci.» 28: 36-98.

Krumhols, Louis A. 1944. check on the fin-cli^pinei method for estimating fish populations. Papers :/iich. Acad. Sci., Arts and Letters for 1943, 29; 281-291.

Lagler, Karl F. 1944. Problems of competition and predation. Trsuns. 9th N. Araer. kl/ildlife Conf. for 1944: 212-219.

19^8. Field and laboratory studies in freshwater fishery biology. 261 pp. "dwards Bros. Inc.

Marktts, Henry C. 1934. Life history of tho Blackhead Minnow (Pimephales promelae). Copeia, 1934: 116-122.

Meek, S. E. 189<^. A report on the fishes of Iowa based upon observa­ tions and collections made during 1890, and 1891* Bur. U. 3. Fish, Co an., 10: 217-348.

Moore, Emmeline 1933. Certain minnows snowing adaptability to conditions in impounded waters. Trans. Amer. Fish. Soo. for 1932, 62: 290-291.

Needham, James G., Jay H. Traver and Yin-Chi Hsu 1935. The biology of mayflies with a syatematio account of north American species. 759 pp. Comstook Publishing Co.

Needham, P. R. 1928. IX. A quantitative study of the fish food supply in selected areas. Suppl. Ann. Rept. N. Y. Coneerv. Dept., 17: 192-206.

Pearse, A. S. 1918. The food of the shore fishes of certain Wisconsin Lakes. Bui. U. S. Bur. Fish, for 1915-16, 35: 249- 292.

Preacott, Gerald w. 1931. Iowa algae. 235 pp. Univ. Iowa Studies in Nat. Hist., 13 (6). - 116

R«ighard, Jacob 1910. Mothods of studying the habits of fishea with an account of the breeding habits of the Horned Dace. Bui. U. S. Bur. Pish, for 1908, 28: 1111-1136.

Richardsont R. S. 19S1. The small bottom and shore fauna of the middle and lower Illinois River an 1 ita connectinii lakes, Chillicothe to irafton; its valuation; its sources of food supply; and ita rel^ition to the fishery. 111. Mat. Hist. Surv., 13: 363-522.

1928. The bottom fauna of the middle Illinois River, 1913-1925. 111. Nat. ffist. Surv., 17: 387-475.

Ricker, 'jfilliam E. 1946. Production and utilization of fisa populations. 3col. L"ono,ir., 16: 373-391.

Ross, Herbert H. 1944. The caddis flies, or Trichoptera, of Illinois. 111. Nat. Hist. Surv., 23: 1-326.

Shelford, Victor E. 1937. Animal communities in temperate America. 2nd Ed. 368 pp. aeotsr. Soc. Chicajo Bui. 5.

Shetter, David S. and Justin W. Leonard 1943. A population study of a limited area in a Michigan trout stream, September, 1940. Trans. Araer. Pish. Soc. for 1942, 72: 35-51.

Sibley, C. K. 1932. Fish food studies. Suppl. Ann. Rept. N. Y. Conaenr. Uept., 21: 180-132.

ani V. N. Rirpsky-Korsakoff j.CojL. Food of certain fiahes in the watershed. Suppl. Ann. Rent. H. Y. Conserv. Dept., 20: 109-120.

Smit|i, Jilbert m. 1933. The fresh water algae of tae (Jnited States. 716 pp. Mcjraw-Hill Book Co., Inc.

Smith, Lloyd L., Jr. and John 3. Lioyle 1945. Factors influencinii production of Yellow Pike-perch, Stizostedion vitreum vitreum, in Minnesota rearintj ponds. Trans. Araer. Fish. Soc. for 1943, 73; 243- 261. - 117 -

Smith, Osgood R. 1940. l^lacer mining silt and Its relation to salmon and trout on the Pacific coast. Trans. Amsr. Pish. Soo. for 1939, 69:225-

Starrett, W. C. 1935. A study of characters for the differentiation of two species of minnows of the ^en^e Notrople. Trans. 111. Acad. Sci. for 1934-35, 2"/: lol.

and Ruth Patrick Ms. Net plankton and bottom microflora Des Moines River, Iowa, i-roc. Acad. Mat. Sol. Phlla. (To be published).

Thompson, Oavld H. anl Francis 0. 'lunt 1930. The fi^hee of Charapai^^n County. Ill, Nat. Hist. Surv., 19: 1-101.

Trautman, Milton B. 1942. Pish distribution anJ abundance correlated with stream gradients as a consideration in stocking prOt^raras. Trans. 7tii N. Araer. tVlldlife Conf. for 194!^; 211-224.

Ulrey, Lorraine, Clifford Ris.:, and ':V111 Scott 1938. Egjs produced by fresh-water fishes. Invest, of Indiana Lakes and Streams, 6: 73-77.

U. S. Department of A^iricultare 1941. Climate and man. 1248 pp. Yearbook of At^ricultore, U. 3. uovt. Printing Office.

U. 3. 7l8t Congress, Sri Session 1931. Des r.oines River lowe. Letter from Seer, of iVar, transmitting report from the Chief of Englniers on the Des ''oines River, Iowa, covorlng navl^jation, flood control, power development, and irrigation. 127 pp. House Doc. , a. S. .lovt. Printing Office

Ward, Henry Baldwin and leor^e Chandler Whipple 1918. Fresh-water biology. 1111 pp. John '.Vlley and Sons, Inc.

Webster* Dwijht A. 1943. Food progression in younj White Perch (f.Iorone araer- icana)(Gmelln) from Bantam Lake, Connecticut. Trans Amer. Fish. Soc. for 194iJ, 72: 136-144. ilesterraan, Fred A. and Albert 3. Hazzard 1945. For better fishing. 14 pp. Klch. Dept. of Conserv - 118 -

XIL ACKNOWLEDOMENTS

The writer wishes to express his appreciation for counsel to Dr. George 0. Hendricksony under whose direction this inves­ tigation was Inaugurated. Dr. Kenneth D. Carlander later assumed direction of the research, and the writer sincerely thanks him for his numkrous sugc^estions, helpful criticisms, and encourage­ ment. The planicton study carried out in conjunction with this investigation was under the direction of Dr. Ada Hayden, to whom the writer is indebted for aid and augjestions in the identifi­ cation of the many algal forms encountered.

Acknowledgment for aid in identification of certain food items is due Dr. Elmo Hardy and Dr. H. H. Knight, of Iowa State

Colletje; Dr. A. C. Kartin, of the Fish and Wildlife Service; and Llr. A. R. Brooks, of the Department of Agriculture of Oanada.

This investigation wo aid not have been possible without the financial aid furnished by the Iowa State Conserv tion Commis­ sion, Iowa Ai^ricultural Experiment Stution, and the Iowa

Industrial Science Research Institute.

The direct administr tive supervision of this research project was originally under Dr. C. J. Drake and later under

Dr. H. K. Harrin, of lov/a State Colleije, and Dr. T. 3. Scott, of the Fish and Wildlife Service and Iowa State College. To these men, the writer is sspecially indebted for their cooperation. - 119 -

Appreciation is expreseed to Mr. Don Briden for hie assist­ ance in the field and laboratory. Aclcnowledgment is also made for field assistance to Uessrs. Harry Harrison, Jr.» Daniel

Nelson, Vard S. Stevens, ''.arvin Hichols, '.'.'illiam H. Tate, James a, Sieh, and Robert E. Clmary.

The writer wishes to thank VT. William Lewis for furnishing the photographs used in Figures 1 through 5. - 180 -

XIII. APPENDICES Table A

Feroentage of occurrence and of tot&l volume of food items in Silvor Cliub (Eybopsia storerienus), Des Moines Rirer,

u m *» fid h O «od cu fi O •n I i<^ fe e i.2? ft 2? h O (/}«AO w O "8 » Data No. fiah examined (26) 1 6 1 15 3 No. fieh empty (2) 0 1 0 1 0 No, collectiona (l6) 1 3 I 6 3 Average volume in ^ Jl 23SL Jl 23L jaL good items in %

Plant material 73 33 lAidet. plant material 27 AmaranthuE sp. (seeds) Graminalcfi ((fruita) 4 33 Ulmus Ep. ('fruits) 7

Aquatic p/mphe & larrae 67 100 IK) 66 A, njraphs & larvae (undet») 100 (Dipterous larvae) Tendipedidae 67 7 Tipulidae 7 (Zphemeroptera nynphs) Ephe^neridae 17 20 Reptageniidae 17 13 33 Trichopters larvae (undet.) 33 33 Bydropsyohidae 13 (Ooleoptera larvae) Gyrinidae 17 Table ^

Pereentage of oeeurrecoe and of total volume of food iterus in Eilver Chub (Hybopala storerianus), Dee Hoines RlTer, 19^6-47* (Continued*)

« bu «o^ CO O CM • ts- •rH -T h Fall (odooj Sumner WBO u:: o (2000-0000) X (Aquetio insect^ V/ater-boataan (Corlxidae)

Adult & emerging Diptera Diptere pupae 17

Adult terrestial inseota 100 17 7 100 Ooleoptere (undet.) 100 17 33 Cerabidae 7 Rhynoophora 33 (HyHenoptera) Foxvicidae 33 (Klgeglleaeoue) Piece of Uhionidae shell 17 Table B

Percentage of occurrenoe and of total voliune of food items in Speckled Dace (EitrariUB aeatiTalia). Dee Moines River, 19^-^7•

h 1 O MtOB o O 11 Data No. fi&h examiaed (3^2) 33 35 26 21 71 l»f l6 17 3^ 50 21 No. fish empty (tS6) 6 2 11 6 2if 5 6 5 6 9 Ko. oollectiona (9^) 10 7 6 5 1^ 5 6 5 l»f 16 6

Average toIubis in ^ 12^ 2i 1$ Food items in %

Pltmt material (undet.) 2 Seeds (undet.) 5 2 5

BottoB ooze 5 7

Aquatic aymphs & larrae 6i ^3 57 99 57 63 65 66 33 A. nympbe & larrae (ondet.) 3 5 6 Diptersua larvae (undet.) 2k 17 u 5 6 6 5 Tendipedidae 27 it6 31 33 57 50 53 60 10 Tipalidae 3 1 Rhaglonidae 2 i:phemeroptera nympha (undet.) 3 Fpheiaeridae 3 IH 19 10 Haptageniidae 6 9 5 6 10 Baetldae 3 Trichoptera larvae (undet.) 3 3 6 3 6 Hydrop aychi dae 3 4 7 H^roptilidae 3 If 1 6 Coleoptera larrae (undet.) 5 1 Hydrophilidae Table B

Percentage of oocurrenoe and of total Toluae of food items in Speckled Daoe (Sxtrariua aeativalie), Dea Moinea Ri-ver, I9I16-U7. (Continued.)

o U u — fi o o e ^vx> •I-P "oO 8 «-4 O •3 CM CD i-< 9 o ft o a cu « • o m o -1^vO CQ^ te to •33 o o (Aquatic inaectal Water-boatman (Corixidae) 5

Adult & energing Dlptera 27 23 33 21 1»» Dlptera pupae (undet.) 3 i 7 2 Teadipedldae pupae 9 Cullcldae pupae 6

Adult & emerging Epheaeroptera

Adtilt terreetial Inaeeta (Coleoptera) Carabldae 2 Staphylinidae 2 (Hyasaoptera) Chala Btogastra

Rotlfera

Entoaostraca 6 5 Cladoeera (undet.) 3 5 Boaalna ap. 3 Cyclopa epp. 1

(Mlacellaneoue) Gaetrotrloba Undetermined inaects (traeea) Table ®

Percentage of occurrence and of total volume of food items in Northern Creek Chub ftro- aaeulatus atromeculrttus). Dee Moinec Fiver, 19^b-U^7»*

c fi) o vo o h — f-t » o iH O o> 1 O •H O wS 5S N O &€ u o S O Oi o Date No. fish sxamiaed (^) k 12 3 19 1 9 6 No. fith eapty (lU) 0 5 1 5 1 1 1 No* collections {kl) 2 11 1 12 1 6 Average voltme ill H « H H 0 12* Food iteiBE in %

Plant i&aterial 25 5 17 Utodet. plant material 17 Seede (Ciraium laaceoietum) 5 Salix embryos 25 Cladophora sp* i

Bottoan oose 5

^^quatic nympha & larvae 75 33 5 67 50 Dipterous larvas ^undst.) U

Tendipedidae 6 33 33 Tipulidee 50 Ifplieieroptera jaynphs (undet.) Tpheraerldae u Heptapenildae i u Trichoptera lerrae (undet.) 50 i Hydropeychidae 33 (Plecoptera nyrnphs) Perlidise Taeniopterygldae 11 Tebl# ^

Percentage of oeeorrenee and of total volume of food Itene In Northern CrceJc Chub (gemotllus atro* laactilatue etraaaottlatus), Des Koines River, 19^-^7* (Continued.)

<•> o *» u «> «-t o o iH o u\a ftOO G) r-l 4 cvj i-? •P I I i H 3 o o 58 a.8 00 rfw o o o (Aquatic Inseetfe'} Water-boataan (Corizidae) 16 u Dytiscidae (adult) i

Adult & emergine Diptera 17 itfiulT Trichoptara 17

Adult terrse-tlal Inaeets 50 33 U 33 to Hemiptera (undet.) o» Coleoptere (undet.) 25 33 5 33 Hynenopt era {und et.) 50 5 Formicidae ColeDptert pupaa 25

Fifioes 53 11 Undet. CyFrinida* 11 Notropis d. dellciosus 16 Notropis spilopterua 5

Ejatoaostraea u Boemina ap. u Cyclops sp. 11 apeoiaena taken July 1, 1947 from BeaTtr Cr«ek in Boone County, Iowa, war* found to contain the following food iT.eTas: Earthsrom (Luabrieua ap.), adult Tan«bri(aiidaa, adult or euarging Culieidaa, and unidentified 1'richoptera larvae. Tabl* ®

Ftroentag* of ooeorrence and of total Toluae of food iteme in Northern CooiaoQ Shiner (Notropis oornutm frontaliB), Dee Moines River, 19^46-^7

_ o o M o rO o • o X> 6D O +3 -CO ao •P h — — o i-i rH a H I H O +3 O o I O CTS 1 a^ i 0 g 0 § 0 1-? CO O a> o •35 a o P, o a o P, H ^ -H 9 0 3 c\j 3 0 fn o O •H to c i -so oc-eo 00 to 0:1 ^ 05 — CO S s o o •r-l 0 o 53° a >-» Data Ho, fisb examined {23fi) 10 63 13 6 23 5 9 25 20 6 No. fish enpty (23) 3 1 1 1 2 6 0 0 2 2 1 k No. eolleetions (110) 7 5 30 6 3 7 21 3 4 9 9 6 ATerage Toluae in f 6^ 20^ 2»t 21^ 26^ 10% 31% 6^ 16» 17i in good items in %

Plant aaterial 20 37 23 Jf 37 ko 11 65 25 10 Undet. plant material 10 2$ 5 15 35 13 Seeds (undet.) 2 Folygonuia sp. seeds 2 Ulmus sp. fruits 20 Saliz sp. embryos 10 6 It Cladophora sp* 13 21 IfJ 23 ko U 15 13 Stigeoolonium sp. 5 Taueheria sp. 2

Bottom ooae 20 13 27 i 33 ki kk

Aquatic nymphs i larvae Uo 25 3^ 33 »^3 25 11 60 20 13 A. nymphs & larvae (undet.) 2 If (Dipterous larrae) Tendipedidae 30 33 )K) Tipulidae I Xphydridae Table 0

Peroentage of ooourrenoe and of total Toluae of food Items in Northern Coomon Shiner (Notropia eornqtua frontalis), Des Koinee RlTer, 19l|6-U7« (Continued.)

o u« o & - 60 c ~ rH O «vX> rH O •P ft 0.7 d I 11 N O fe. J ti £8 58 u CO 4^ •«o * CO —' o o 3 o Ephemeroptera nymphs (undet.) 13 IT 2 Xphemeridae 10 22 17 26 6 Heptageniidae 13 5 17 6 12 10 Baetidae 13

Triohoptera larrae (undet*) 2 E^dropsyehidae 2 16 Leptoceridae 2 11 (Pleooptera nymphs) Taeniopterygidae (Coleoptera larrae) Haliplidae

(Aquatic inBeete) Wateroboatman (Corizidae) »» 17 U 12 1? Oyrinidae (Ad.) Hydrophilidae (Ad.)

Adult & emerging Diptera 20 5 17 12 11 Adult & emerging Ephemeroptera 2 k Adult 4 emerging Triohoptera 3 * k

Diptera pupae

Adult terrestial insects Hemi ptera (undet.) 2 If Miridae Cioadellidae 2 13 Table O

Pareentage of ooeurrenoe and of total Toltme of food items in Northern Canon Shiner (Hotropia eornutaa frontalis). Dee Koines RiTer, 19l»6-U7, (Continued.)

- ' Sg h — |4 4» 9 i O H ai H O MvO 8 ft I CM ' 5 H Is 43 ON e o +» ji I o a' U aCi-4 £ P.< AA o o o 23^ Coleoptera (ondet.) 10 IT 8 33 23 w TT Carabidae 2 4 20 13 Staphyllnidae 13 Tenebrlonidaa 13 Bhyneophora 3

Hyitenoptera (undat.) 13 i 12 11 5 lohneuBonidae 5 N formieldae 5 <0

Entoaoetraca 10 24 Cladoeera (undet.) 10 Boeolna 2lf Daphnia longiapina if Cyolops app* 12 D.iaptawis spp. 12

Pisoes (uadet.) 2 Cyprinidae 10

(Miseellaneoua) Spider (Araehnlda) 2 Sarthworm (Luabrleus sp.) 13 Coleoptera pupae 2 Undetermined insecta (traces) 25 3 15 13 if 13 Unidentified material 25 6 Table S

Percentage of ocourrenee and of total Tolume of food items in Rosyfaee Shiner (Notropis rnbellm), Des Moines River,

o is S o •p-io H S « ot r-t I •» I m a p >4 i ^2? Hn-co £8*3 o O •s h. Data No. fish ezaained (^} 1 20 5 1 7 13 3 No. fish empty (1^) 0 2 6 4 1 1+ 0 1 No. oollections (^2) 1 10 13 2 1 k ? 2 Average volume in % iH loi 1% lit 0 2i 12lt Food items in %

Plant material 100 5 i 33 TJndet. plant material 5 Seed (undet.) i Salix sp. einbryos 100 33

Bottom oose 15 6

Aquatic nymphs & larvae 25 15 ?3 33 Dipterous larvae (undet.) 5 23 Tendipedidae 15 3 »»3 23 Sphemeroptera nymphs (undet.) 5 6 Bphemeridae Ik 33 Heptageniidae 5 3 (Coleoptera larvae) Hydrophilidae 3

(Aquatic insects) tfater^boatnan (Corizidae} 20 Table ®

Percentage of oocurrenca end of total Tolume of food iteas In Rosyface f^hiner (Notropls rutoellns). Dee Koines Blver, 19^6-47. (Continued*}

o 8 8 o U <-i » CVI H W p-» o rH O a> O SS si r-4 O •P r-t f* I Id H k h o ?>• N O o &0 P, o «r4 ucTi xo a o o o o as Adult fc emerging Diptera* 40 44 Adult & emerging Ephemeroptera 20 Adult 4 emerging Trioboptera 6

Diptera pupae 15

Adult terrestial ineecte 100 15 53 33 Hemi pt era (lind et.} 1^ Jliridee 6 Lygaeidae 3 Cicadellidee 3 Coleoptera (undet.) 100 5 26 Cerabidae 3 ^jtaphylinidae 33 Tenebrionidae 9 Hyi:ienoptera (undet.) 10 3 lohneuaonidae

Entomoetraea** 15 Boaialna i Cyclops spp. 15 Diaptaiaoue spp. 15 Table S

Feretntage of oooorrenoe and of total Tolume of food itens in Ro^face shiner (Hotropie rubellae), Oea Noinee RiTer, 19^^6-47. (Continued.)

o (4 S 0 8 «oS • H a cvj 1 C5N 4*« "• J, ctf o to CO i: o a.° (Wiaeellaneom) Tish egga Lepidoptera larrae (Phalaenidae) Iftidetemined inseots (traeet} Unidentified naterial 1

*Fa]ftiliea of Diptera detemined were Tendipedidae and Seiaridae. a ^*The apriag ooonrrenoee of Entosoatraoa «ere between April 2 and April 19^7• to Tabl# F

P*ro«ntage of oeeurreooe and of total Tolune of food Items in Spotfin Shiner (Notropia apiloptarm), Da a Moinea River, 19^»6-47.

0 g *» i H W H 0 wo s:$ |S •-4 0 f-i 0 ? CVj si 6» il 2? ei fig m 00 35H "W Is 1 ® 21 ll II 0 0 u 4 aa Data No. fish examined (^11) 30 67 255 56 77 106 12 13 *•5 ?! No. fiah eapty (IjS) 3 W lb 6 26 26 10 1^ i No. oolleotiona (173) i 10 ^10 10 25 5 1^ 16 Average yoluaa in jt 20i 26i IH i2l il rood itema in

Plant material ^ 60 27 9 25 33 20 25 Uhdet. Plant material 20 7 6 11 9 9 Seeds (undet.) Polygonum ap. aeeda Saliz ap. embryoa 13 15 7 13 Lepidium virginieun (pods) O Buds or embryoa (undet.) 3

Spirogyra sp. T Gladophora ap. 7 3^2 12 17 U Sbisocloniua sp. T Stlgeoeloniim ap. 4 2 1

Bottom ooae 5 5 1 1

Aqoatio nympha & larvae 27 39 1^3 3^ 17 20 6 ^ 22 19 A. nymphs & larvae (undet.) 3 1 2 2 3 Tablt f

Peroentage of ocoorrence and of total voluae of food items in Spotfin Shiner (Notropis fepllcpterus), Des Moines RlTer, (Continued.)

>4 « o o «o u ^ o QOO a> o V vo 4* V) r-l 58 3 o •^8 to ca TBO :s o M O o o O II•H O

Dipterous larrae (ondet.) 2 TT T Tendipedidae 17 16 15 1^ 9 6 If 33 i^3 7 Tipulidae 10 k 1 1 5 If Culieidae 1 1 Zygoptera nynph 1 Anisoptera nymph 1 T 2 1 Ephemeroptera nymphs (undet.) 7 6 2 k 9 2 Ephemeridae 1 12 5 li 1 3 Heptageniidae 1 3 5 3 Baetidae 1 2 J " Triehoptera larvae (undet.) 2 k Hydropsyehidae 5 20 2 Psallidae T Pleeoptera nymphs (undst.) t Ta eni opt eryg idae 1 Perlidae 1 3 Coleoptera larvae (undet.) 1 1 2 ayrinidae T Dytiscidae T 1 Hydrophilidae 1 3

(Aquatic insects) Water-boatnan (Corixidac) 1 Gerridae T ayrinidae (adults) 1 Oytiaoidae (adults) 2 Hydrophilidae (adults) 2 Tabic r

Peroantage of oeourra&ee and of total Toluaa of food itaaia in Spotfia Shiner (Notropia apiloptarua), Daa Hoinea RiTer, 19^6-^7. (Continued.)

O « 8 K\ S8 u ^ 8 o § ds •H O A iS o £ o IM O •as •«Q S O II a O jas 33 yr IT Tfl 55" ir-TT (AduTt Pleooptara) Perlidaa

Adult & emerging Epheaeroptera 3 2 11 12 3 Adult & amereing Triohoptara 2 3 1 Diptera pnpae 3 5 I Triehoptera pupaa 1

Adult terreatial inaeota 33 3^ 2>* li 17 k 23 9 25 Looaatidae 1 Gyrallidae T Oliryaopidae T Hamiptera (undat.) 1 3 Miridaa T 3 lorgaeidae T Cieadellidaa 2 3 6 Coleoptera (undat.) 20 l6 9 11 10 19 15 3 Carabidaa 3 7^ 2 1 1 13 Staphylinidaa 3 3 2 1 3 Anthioidaa 1 Blateridae Tanabrionidaa 3 T 3 Soarabaaidaa 7 1 2 Chryaoaelidaa T 1 Bhynoophora 7 1 3 Table T

Percentage of occurrence and of total volujne of food iteias In Spotfln Shiner (Notropls Bpllopterus), Dee Molnee RlTer, ISko-kj. (Continued.)

u o o o 8 o « B S" cm tiBo « rH 0 o H O a CM T*' - I

BntaaoBtraea J 1 16 Entoi&OBtraoa (undet.) 3 (A

(Miscellaneous) Spider (Arachnlda) 7 2 Lepldoptera larvae (undet.) 3 T I Phalaenldae larrae 3 Centipede (Chllopoda) 2 Insect eggs Tabl* T

Percentage of oecurrenee and of total Tolone of food Itene in Spotfiu Shiner (Notropls spllopteraa), Dee Moines RlTer, 19^-^7. (Continued.)

« o «D +> H O « vo SB V w m I-I cu H O >-l II* ON • O 5!Li •* 1 s i N O o OiO CQ QO » o U} O •38 TSO "to s o o o Coal T 2 1 Piece of yarn T nadete;iained Insects (traces) 17 7 5 1 3 5 Unidentified material 3 2 1 3

^he following fanllles of emerging and adult Diptera were identified: Tendipedldae, Tipulldae, Culiciias, Simulldae, Ceeidamyildae, Enipldidae, Dollchopodldae, Sciaridae, £yrphidne, and Taohlnida«« No occurrences of Pisces were noted; in the laboratory young N. spilopterus (less than 20 la.n.T.L.) were placed in an aq.uarlum with large adults of N. spilopteruT which had not been fed for &eT«ral days. Imoediately they started to feed on the y?ung fish and continued until all the young had been devoured* Further studies on this species might reveal STldence that it occasionally feeds on other fishes under natural conditions* Table O

Percentage of ooourrenee and of total Tolume of food iteraa in Central Blgnoutli Shiner (Motropie dor- •alls doraalls), Des Moines River, 19^-^7•

o 8 o fs8 eo a f* wo feO rt

Plant material l6 6 u 11 21 16 Dhdet. plant material l6 2 7 19 16 Iragrostls sp. seeds 1 Cyperace?; fruits 1 S^iz ap. e -ibryoa 5 Cladophora sp. Tauoheria sp. 1

Bottom ooze 26 7 10 7 kl 17 2

Aquatic nyapha & larvae 75 57 64 52 37 20 56 51 16 A. nymphs & larvae (undet.) 5 7 3 5 Dipterous larvae (undet.) 3 u k 16 Tendipedidae 75 2u ^3 32 17 10 65 24 Tipulidae 25 3 7 3 3 56 i Fphydridee 6

Xpheraeroptera nympha (undet.) 6 3 13 h 11 Ephesieridae lu 19 2 ri 3 Heptageniidae 25 7 1 5 Baetidae 2 Table ®

Feroentage of occurrence and of total volume of food items in Central Bigr.outh Chinar (Notropls dor- •alls doraalis), Des Koines River, 19^+6-^7. (Continued.)

o • o o 8 eo •P ^ u r^ too 4»-«0 0 o — W H ^ H o tn (M a r-l at-* H O i-l 1 o S J -38 Ct 1 |8 o fc o U Xi O (2000) 58 CO *5 w 55 ISO Sunmer 5 ^ aoY) o is o •«o o o as TriohoirtarB larvae (undet.} 3 3 7 3 2 2 EydropByehida* 6 7 1 13 33 (Pleeoptera nymphB) Taenlopterygidae 7 (Cole opt ere lairvae) Hallplida* 2 7 Dytlscidae 1 Hydrophilidae 1 1 33

(Aquatic Insects) Uater-boatman (Corixidae) 2 6 25 11 2 k Gyrinidae 3 i\dult k emerging Dlptera* Ik ik 19 13 39 25 11 i

(Adult Pleeoptera) Taeniopterygidae 2 Isoperlidae 2

Adult & energing Epheneroptere 7 13 Adult & emerging Trichoptera 7 3 Diptera pupae (undet.) 2 7 3 1 11 Tendipedldae inipae 7 Simulidae pupae 7 Tablt ®

Pereantage of occurrence and of total volume of food Items In Central Blgmouth f:hlner (Notropla dor» •alls dorsalia). Dee Moines River, 19^-^7• (Continued.)

f£ o *> 8 • o (d u s « rH u\o eo § I-d- • H c: oi X i-l XJ <7N d8 I I 19*+6

(2000) (0000) s§ Fall Spring Summer Summer •3,8 n-S (0000) 0^ -ao a o o O o

Adult terrestial Insects 16 ^ 21 16 20 23 te 33 33 Hemiptera (undet.) 3 Aphldldae 7 Cicadelliilae 16 Coleoptera (undet.) l6 25 3 7 10 ik 33 Carabidae 1 3 3 17 l6 Staphylinidae 1 I Scarabaeidae 1 Rhyncophora Hynenoptera (andet.) 25 1 3 6 17 2 16 lehaeumonidae 2 Pormicidae 3 3 3 j-atonostraca** 1 7 Mo Boflaina 7 39 Copepoda (undet.) 1 Immature copepoda 2 C/clopa spp. 26 Diaptamous epp. 12

Pbytoplankton 3 Tabl* ®

Fvrecntage of oeeurr«nc« and of total Toltine of food ttema in Central Blgnouth Shiner (Notrople dor- •alia doraalie), Dea Moinea River, 19'(6-47* (CoatiniMd*)

9. • o r-r -T' ^01 -ro So r-t I kvO nop •4»ev CVI H « H 1-4 3-^

*In ao nany instanoea it waa not poaslble to make an aoeorate deterxination of the eserging tmd adult Diptera and to avoid giving a miarepreeentation of the abondanoe or aearoity of certain faailiee, the faRilies are therefore inoluded in the table with the order. FaBiliea determined were: Tendipedidae, Cttlieidae, Tipulidae, and Ceoidoayiidae* **rhe ^ ooourrenoee of Entoaostraea in the fall were at the cloee of the aeaeoo. Table ^

Fareentage of ooourrenoe and of total Tolune of food items in Southwestern Sand Shiner (Notropis deliO" iOBUB delicioBua), Dee Moines Rirer, 19^t6-U7»

u m CO to •p U h- 0) o *4 ' hvo e iH « « H 18 i o 4> I 1^3 t ON i o iSg 51 s o ^ o 58 CO -to I've 05 ^ jfW llCQ-S o •H o P o « o a 2 No. fiah ezefflined (^66} ir 3^ 125 28 5l 56 77 W 21 73 23 No. fish empty (76) 0 2 C k 15 1^ 2 3 11 3 6 No. eollectionB (1^1) k ?5 9 i 11 25 6 5 l6 17 7 Arerage rolume in % 20jt lUi iH 22^ 12^t 11^ 15lt Food items in J

Plant laaterial 2^ 12 7 k 2 17 5 33 Qndet. Plant material 19 5 k 17 27 k Seeds (undet.) 1 If 13 to Polygonum sp. seed* 1 17 I Eragrostis sp. seede 1 6 5 Qrafflinale« fruits 9 Amaranthua ap. seeda 2 Salix embryos 6 13 5 k 2 13 Cladophora sp. 9 1

Bottom oose 5< i»» 12 25 90 6l 3< kl 16 9

Aquatic nymphs & larrae 12 33 23 10 19 ki 36 26 Undet. aquatio nymidia & larra* 6 6 2 1 Dipterous larvae (undet.) 6 2 2 5 k Tendipedidae 6 6 7 16 2 5 H5 Itf Tipulidae 1 1 5 Simulidae 1 Ephydridae 2 Table H

Psreentage of oeeurrenee and of total TOluoe of food iteas in Soutlurestern Sand shiner (Hotropie delio- iostta delieiostts), Des Koines RiTer, 19^6-^7* (Continued.)

& ^ 2 aoo >4 o rH O « vO * i 1^ 4* r-t 58 JS ft* Jj 2? _ o o 00 CO CO S '•8 o 3 0 0 ^ 1 s 3 Ephemeroptera nymphs (undet.) 667^^ 10 Ephemeridae 6 9 ^ 21 IS 'f 1 2 Heptageniidae 6 2 2 1 11 21 Baetidae 2 Triehoptera larvae (undet.) 7 8 2 Hydrops/ehidae 67^ 9 k Hydroptilidae 2 (Pleeoptera nymphs) Taeniopterygidae Perlidae 3 Coleoptera larrae (undet.) 'ilk Haliplidae 1 Bydrophilidae 2

(Aquatic inseots) tfater-boatnan (Corixidae) 1 H 2 5 A* Coleoptera (undet.) 1 1 Hydrophilidae 1 ^

Adult or energing Diptera (undet.)6 6 6 1^ 6 I6 i 17 Tendipedidae 2 ^ 5 16

Diptera pupae (und^t.) H Ad^t U emerging gphemeroptera 3 2 1^ 2 Adult S emerging Triehoptera 1 I'f 2 5 Table ^

Fereentage of ooeurranee and of total Tolurae of food items in Southwestern Sand Shiner (Notropis delio- iosus delioiosus), Des Moines Rirer, (Continued.)

o to « h— o o « •P H o o +» s s:# « o f-< cu Vl iH «0O C0 ••p at I d8 t3 I rt evi p. HO £§ ^8 W T«0 a> S h o •H-W S.I o "* O o O PS o Adult terreetial insects 18^ 31 13 5 IT 2 Miridae 1 Cieadellidas Coleoptera (undet.) 12 25 3 k 11 Carabidae 1 k Staphjrllnidae 6 2 Tenebrionidac 1 Curculionidae 1 2 HyBsnoptera (undet*) 2 2 ForBieidae 1 k

Entomostraea 19 BosBina li Copepoda (undet*) 1 Cyolops spp* i Diaptaaous spp* 7 Isaatare copepoda 1

(Miecellaneous) Coal 1 Spider (Araohnida) 1 Coleoptera pupae Lepidoptere larvae (undet.) k Phalaenidae larrae 7 Undetermined insects (traces) 1^ 19 7 2 If Unidentified material 19 1 2 Tabl*

Pareantage of ooeorranoe and of total Toloma of food items in Suokeraouth Minaoar (Rienaeobitts aira* bilia), Dea Moines Hirer, 19^6-^7.

0

9if 0 CU Fall fii u (0000) (0000) 0 V (2000) "'BO Summer Suamar II (0400-1400)" — High-water || Data No. fish examined (1^) 17 k 5 27 9 11 33 2H 3 Bo. fish empty (2^) 2 1 3 3 0 1 i 2 9 0 No. eolleetiOBs (6^) 11 3 12 2 13 10 ATerage volaae in 2LJI li 7^ 21* li -2i 21 k good items in % il

Plant material (undet.)

Bottoa ooae 1^ 13 56

Aquatic nymphs & larrae 76 50 50 ko 41 100 i2 67 A. nymphs & larrae (undet.) 6 u 9 li 33 Dipterous larrae (undet.) 6 13 16 8^ Tendipedidae 59 3< 25 20 67 »»5 29 70 Its 33 Tipulidae % 33 13

(Epheneroptera nymphs) Ephemeridae 25 Heptageniidae 20

Trichoptera larrae (undet.) 6 7 82 14 k i^dropayohidaa 12 7 11 9 (Pleoopters nymphs) Ferlidae h 1% Tabla I

P«ro«atage of ooourrmoo and of total voluma of food Itaas in SaoJcazsouth minnow (Fhanaooteiug wira- bilia), Daa Moiaaa RiTer, 1946*^7. (Continued.)

0 — tep « o a o o O H S ^ ::iS a? H-a" 31 1 c ° S CU £ o • o row w "«0 II •3€ o o o (Coleoptara larraa) Ojrinidaa 13 Hydrophilidaa

(Aqaatio ineeote) k'ater-boatman (Corizidaa) k

Adnlt i anerging Diptere 13 25 33 17 Diptara pupae (undet.) 6 I Tendipedidaa pupae 6 13

(Macellaneous) Earthworm (Luabrioua ap.) 33 Spider (Araohnida) Piece of a TJnionidae ahell Ubdetemined inaeet (traeaa) 20 Tabl« ^

Fereentage of oeourrenoe and of total TolUBie of food items in Brassy Minnow (gybognathas hanldasoni), Des Moines Sirer, 1946-^7•

o o ^vOUO & o h8 vO spi-i •H^ rA i CXI 88 H CU 4* M •*4^ CU 54 M O U Is If (0 S •to w >80 o o o o o Ko* fi^ exaidned (3^) 4 U 3 1 2 No. fish empty (3) 0 0 0 0 0 2 1 No. eolleotions (30) 3 9 3 1 k i 2 Average yoluae in ^ 65 JO 7? 2i Food iteas in ^

Bottoa oose 100 100 100 100 100 75 90 Tabic K

Percentage of ooeurrence and of total volune of food iteme In Fathead Hinnoir (Piaephalee prowielas proanelaB), Dee Moines River,

o o 8 M S • § » vi> IS i^'S |8 <-4 "S 1 a tt> o WW h •«o o o o No. fish ezamined (23) 6 3 2 2 1 7 2 No. fieh empty (1) 0 1 0 0 0 0 0 No. aoUeetions (1^) 5 1 1 2 1 6 2 Average voluae in ^ 6^ 2 73 5i 1 ?? 30 Food itea ia f>

Botton ooze 100 67 100 100 100 100 100 ii^ c» '''One speoinen fron BeaTer Creek (July 1, 19^7) contained 80% snail dipterooB larvae* Tabla L

Peroantage of oocurrenee and of total TOIUM of food itaaa In Bullhead Hlnno* (Ceratlohthy peraplouna). Des Hoinee River, 19^6-47*

u "F o o f-4 CVJ SS r-l CM 3k4 O ig- Xt tH 4S f3i U> 3 s 'S Data No. fish examined (203) 13 12 5 1 53 10 i 20 ks 32 No* fish eapty (31) 0 1 2 1 6 3 1 3 i 6 No. colleotions (70) 7 7 3 1 iH 5 2 6 li 7 Average Tolume in ^ 2J3t 3^ 0 23* i7?t 2ii, n 16^6 Food items ia %' Plant material 23 l»9 30 75 5 27 22 UndetT^jlant" oaterial 15 2 10 12 16 Seeds (undet.} 10 Eragrostis sp. seeds 20 75 5 Cyperaoea fruits 1W Hollugo Tertioillata 2 Qraminales fruits 3 Saliz embryos t 3 Cladophora sp. e 4 fiottoa cose 17 3H 6

Aquatie nymphs & larras 62 He Ho 9 70 H5 9 A. nymfAS It larrae (undet.) 2 Dipterous larvae (undet.) 2 Tendipedidae 31 17 2 60 22 3 Tipulidas 3^ 2 30 Iphydridae 17 Simulidas 6 Table ^

Percentage of oceurrenoe and of total voluae of food Items In Bullhead Hlnnoir (Ceratlchthye pereplqutts), Des Hoinee Rirer, 19^'-47* (Continued.)

& o 8 h «cd 1 • o m rH IOJ ct cu r-l I *' J h 31 a Q •S^ fi| £ o o •asri I'M) ui' » O O 53 1 (Epheneroptera nymphs) Ephemeridae i 20 2 Heptagenildae tS i 10 Baetidae 2 Trichoptera larrae (undet.) 2 5 2 Hydropsychldae 2 10 5 6 Pleooptera nymphs (undet.) 2 Taeniopterygldae nymphs Perildae nymphs ^ Coleoptera larrae (undet*) 23 20 Hydrophllidae larrae 20 2

(Aquatic insectb) fa/ater-boatman (Corixldae) k 10 12 10 3 Oyrinidae (Adult) 5

Adult & emerging Diptera (undet.) 23 17 'K) 13 10 k 3 TendTpedidae 10 Psychodldae 2 Syrphidae 3

Adult terreatial insects 23 k 10 9 Headptera (undet.) 2 Cicadellidae 3 Coleoptera (undet.) 2 3 Carabidae 2 Scarabaeidae 2 Staphylinidae Table L

Pereantage of ooeurrenee and of total roluae of food items in Bnllliead Minnow (Ceratlchthya perspiaaue), Dea Hoinea Hirer, 19't6«>f7« (Continued.)

•u o o s 8 cvi o h o • ON h q 1^ Tl o •32?

1^ Fall •h-wj (0000) a-w Sunner o (0000) o a o •Ji o a

Hyaanoptera (undet.) i 10 Fozsicldae 6

KBtoaoatraea 2$ BosBina sp. 20 Copepoda (undet.) 5 Cyclops Bp* 15 Diaptamous sp. 10

Wiaeellaneous Xartfaworm (lumbrious sp.) 22 Lepidoptera larrae (undet.} 13 Terreatial Coleoptera larra 9 Terreetial Coleoptera pupa 3 Spider (Arachnida) 3 Inseot eggB i Q^detenained insects (traees) 25 Otaidentified material 6 i Tabl« H

Peroentag« of ooourrenoe and of total volume of food Iteas in Bluntnoae Minnow (Hyborhynchua notatua), Dea Koines River, 19'46-'t7*

8 o 4f-¥i evi u\o -I •H O SI H o '* m o ? o mxo 58 O.C i.8 w • o o 55 V) w toto o o as Data No. fiah examined (6^) 15 7 6 6 3 3 6 12 10 No* fialx empty (11) 2 3 0 0 0 1 1 1 3 Ho. eoUeotiona (^2) 10 3 5 5 3 2 6 11 7 Average TOluae in ^ JLl 105t iZl iZl 20^ i2l Food itama in jh

Plant material l»f 17 10 IMdet* plant material l4 17 Seeda (undet.) 10

Bottom ooae ^0 29 «3 100 100 33 50 50 »I0»

Aquatio nyapha i larvae 7 lU 35 17 (Dipteroua larvae) Tendipedidae 1^ 17 (Ephemeroptera nymphs) Kphsmeridae (Triohoptera larvae) Bydropeychidae (Pleooptera nympha) Taeniopterygidae 17

Adult terreatial inaeeta 17 33 Coleoptera (undet•} 17 33

*CMefly mud, few to no diatama Tabic H

Pereentage of ooourrenee and of total voluffle of food Itema in Bluntnose Minnow (Hyborhynchue notatus). Dee Moines River, 19^^^7* (Continued*)

o 0 o t4VO »s 9 O H O ® H {3 C\J •H I 1 5 •35 o £8 ht O u {Q ^ Ttyo 01-is too o o Entoaostraca 8 Cyclops Bp.

Uttacellaneoug) Lepidoptera larrae (uttdet.) 10 Unidentified aaterial 10

""Chiefly and, few to no diatoiUB. cn Table ^

Pereeatage of ooourrenoe and of total Tolume of food Items la Central StoneroUer (Campostttaa anc«a- lon pullua), Des Holnes River» igU6-U7«

o g o o u — u — \0 (do •» to « O a®? «B h-H « o O o |S 10 I'i o a ® No. fleh examiaed (20) ~Tr T- 3 2 -Tf 2 T No. fish empty (2) 0 0 1 0 0 0 1 No. oollections (17) k 1 3 2 k 2 1 Averaee volume In jt io 6 JL JL J5L JL 0 Food items in ^ I Bottom ooze 100 100 67 100 100 100 M 1^OI Aquatic nynphs & lai^rae 25 50 I Dipterous larvae 25 50 Tendipedidae 25 50 - 156 -

Tabl« 0

foot habita of mlao«llan«oua flahea Dea Hoinei RlTar, Booao County, loura

Family Cypi'lttidaa

Vaatern blaoknose daoa (Rliinichthys atratulua neleagria) 1 apaolaoa. (IJ Gaptemoer 1^, 19^ (0000), contained 1 Ephanardia*

Hornyhead ohub (tToooiaia blguttatua) 1 speoimaa. (1) High wateir~19^?7r"oontaIned' bot' ac ooBe«

River abinar (ilotropia blenniua) 7 Bpaoinens. (1) High watrar 19%* contained trace a of plant natarial. {1} Samper 19*^6, araj/t:'. (2) Fall I9^t i contained a mii now. 1 " '' , traoea of an adult Colooptera and 1 Eph«neridae nynpb. (2) Spring: 19^7» 1 enpty. 1 contained a watar-boutoan.

Common enarald shiner (Hotropia a. atherinoidea) ^ apeoimena. (1) Higb vuater I9U6, contaiaed trace of an insect. (1) Sumraer 19'^t contained 2 Epheneridae ny«ptus. (1) Fall 19^, contained an adult Uymanoptera. (ij Spring, 19^7• " 2 Lepidoptera larvue (Fhalaenidae) and plant fibrea. (1) Higb water 19^7• contained 1 hollgraanita larra and 3 Homoptora (Cioad- ellidae).

Carp (Cyprinus oarpio) 2 speoiaena. (1) Suoraer 19%, (33 m. S.L.) contained 1 peroant plant aatarial. (1} " " * (30 nm. S.L.) " 10 percent KpbaBteridae nTmphs (Kphoron ap.) and 10 peroant onidontified inaeot naterial.

Faallj AMiuridao

Black bullhead (Aanoiurua n. melaa) 1 apeoimen. (1) May 25, 19*^7» (7«5" T.L. J contained 1 orayfiah {CambaruB ap.).

Fasiily Centrarchidae

Nojrtharn amallmouth baas (Micropterua d» dolomiattj 'j apeoimena. (75 to 90 Bn. ii.L.) (5) Summer 19^, 2 enpty. 1 contained n Lepidoptera larra and a i^eptegeniidae nynph. 2 " udult Coleoptera (terraatialJ. 156 -

Table 0

Tood liabits at •laAellaMous fishes Dee Hoinea SiToir, Boone Ononty, loira. (Cmtlnaed)

Sleaderbead darter oontlnued. (2) fall IS'^* 1 oont&ined Siomlldae larvae, Tendlpedidae larvae and Col- eoptera larvae. 1 oontaiaed Slmulidae larvae, Tendlpedidae larvae, Heptag- enildae oynph, and emerging Diite7*a. (9) High water 19*17» ^ empty. 1 contained 2 land analls (Qestroeopa ep.). 1 ** Anlaoptera nymph and Tendlpedidae larvae 1 *1 traees of an Inseot larva. 1 " Heptegenlidae nynph and Trlohoptera ease 1 I' trace ^Jpheneroptera nyaph.

BiMkslded darter {Hadroptems Macttlatus) 26 apeolmena. (7) SUBaer 19^» 3 contained EeptageniIdae nympha. 1 •* •* •* and Tendlpedidae lervae. 1 contained Bactldae nyapha. 1 M n aQd Tendlpedidae larvae. 1 " undetermined dipterous larva. (7) Adl 19^, 1 contained Hydropayehidae larvae, Heptageniidae nynpha, SlKUlldae larvae, and Tendlpedidae larvae. 2 contained Baetldae nymiha. 1 " n n and Tendlpedidae larvae. 1 " Hejjtagenlldae nymphs and Tendlpedidae larvae. 1 " traces of an Inseot larva. 1 II water<-boatraan. {k) Vlnter 191^6-^7, 2 oonteined Plecopt.era nympha (Taenlopteryx naura) and Tendlpedidae larfae. 1 oontained Ephemeridae nyraphe, Triohoptera ease and Tendipadldae larvae. 1 oontaintd Heptageniidae nympha, Hydropsychidas and Tendlpedidae larvae* (4) Spring 19^7» 2 contained Baetidae nympha. 1 <1 Hei tageniidae nynpha. 1 '• " " , Trichoptera case and Tendlpedidae larvae, (k) High water 19''*7» 1 eapty. 1 contained a leech (Hirudinea). 1 *< a water-boatman and Baetldae nympha. 1 « n II n Heptaf^enlldae nynpha.

Central Johnny darter (Boleo&oma n. nigrum) epeoiraens. (1^) dammer 19^» 12 contained Tendlpedidae larvas. 1 M R H and a Heptageniidae - 157

Table 0

Food habits of aiaeallaaaous fiehes Dea Koines Riyar, Boone County, Iowa. (Coatinued)

Family Catostoiaidae

Carpsuakar (Carpiodea spp.} 12 speolaeaa. (29 to 120 am. S.L.) (3) Fall 19^, 1 enpty. 2 eoatainad bottoa ooza. (2} Winter 19^6-^7t empty, (4) Spring 19^7* 1 oontained 2 Tendipedidae larrae and bottoa ooaa* 2 *< entomoetraea. 1 " ^ Tendipedidae larraa. (2) High water 1947, contained bottoa ooaa. (1) Suornar 19^7> ooatalned bottoa ooze.

Common wbita sucker (Catoatoaas c. ooBBnerBongii) 1 spaelman. (1) May 3, 19^7 • nn. S.L.} enpty.

BMMan redhorae (Moxoatona aureolua) 1 apeelBaa. (1) April 13, 194b, (W.5 m. S.L.) eapty.

Family Ivreldaa

Tallpw plkeparch (Stlaoetadion t. Titraua) 3 apeclmaaa. (1) Juna 27, 19*^, £.L.) ampty. (2) Juna 19, 1947» (27 and 29 m. S.L. } enpty.

Wastam aand darter (AMoerypta elara) 9 apeolmsna. {d) Sasmer 19^, 3 empty. 1 contained adulte of Coleoptera and Hyoanoptera aai Selix embryos, 2 contained Tandlpedidas lerrae. 1 f " *' and Bsetidae nyapba. 1 " ** <* and HeptaEenlidaa nymphs. {1} Fall 19^, 1 contained Tendipedidae larvae.

Slandarhaad darter (Hadppterua phoxce;:halus) 1^ specimens. (7) Summar I9H6, 1 emj-ty. 1 contained trace of Ooleoptera larvae. 1 " Tiiuditediiae larvae and trace of Fphewarop- tera nymph. 1 contained Heptageaiidae nympha and flecoptera nymph (Acroneuria sp.) 1 contained Heptngenildae nyrsphs aa»t Hydropaychldae larrae. 2 K H " • 1 n Baatldaa nymphs and dipterous pupa*. - 158 - Tabic 0

7ood habits •iseallanaoas fishes Das Hoinas Hirer, Booaa County, Iowa. (OoatloBod)

Central Johnny darter oontinued. nymph. 1 contained an rj^eaeridae nynph (Ephoron sp«) 1 •* emerginfi Diptera. (21) rsii 19^, 3 empty. 1 oontaincd emerging Dirt era. 1 n iubect eggs. 3 " Tendipedidae and Tipulidae larraa. 1 >* bottom ooze* 1 •* Baetidae nynphs and Tendipedidae larras. 5 " Tendipedidae larree. 1 " HeptagenLidae nyiiq>hs, Hydropsychidae and Tendipedidae larrae. If contained Tliulidae larree. 1 " " « and eaarging Diptera* (1) Winter ISkS'MiJ, 1 contained Tendipedidae larrae. (5) Spring 19^^?, 1 euapty. 3 contained Tendipedidae larrae. 1 " 'I " and entoQoetraoa. (2J High water 19^7, 2 contained Tendipedidae larrne. - 159 -

Tabls P

Sis« distribution of :ioutbHeGtern Gand Shlntr (Notropis d. delloiOBUs) from Des Molnee niTer oollbotlona. "

Standard July 31 Oct. 5 NOT. 23 MQR.2^ Aug* 1 HOT. 21 Laoigth I9U6 19'»6 I9U6 19'»7 I9H7 19»f7 la Milliaeters

16-17 2 1 3 1^-19 2 5 lU 37 20-21 13 17 26 105 22-23 25 50 3»^ 1 96 2l»-25 k9 176 10 75 26-27 63 222 19 53 2^29 79 262 31 60 32

30.31 6 ^3 ll»7 7 17 32-33 6 12 25 6 16^ 16 3^-35 6 13 H 202 33 36-37 21 u 19 1 1^ 3^39 17 13 H7 2 ii^ii 35

ko-kl 9 16 ?2 2 U (•2-43 9 16 <3 5 16 5 M4-H5 16 15 46 9 5 1 46-lf7 21 6 39 5 5 9 11 79 7

50-51 1 5 31 2 1 52-53 1 12 1 2 9it-55 1 3 1 56-57 1

62-63 1

Total Monber 13»» 3^ 1290 24^ 972 57H 160 -

Table Q

OrganiHis ooRposiag the bott

HItte-RrecB algaa Diatoaa continued Heriiiiiopedla glauoa Pinnnlaria viridis Oaaillatoria prolifloa Caloneie faseiata Dlatcma 1 Lewlsii Heloeira ambigua " Schuffiaoniana » "7.tenuis " siUioula T. ventrieosa " grairalata " ** T. angttstlSBiiMi Hsidiun affina " aufflRuloides " " r« aKphirhynehuA n dubiun Cyelotella HeaagbiJiiaxia " iridlB

Stephaaodisous astraea Stauroneis astraea t* ninutulua " t* aiaotula Hiagarae •atilsttrokla rulgaris OyroaigBa acuadnatuB Synedra a«as n attenuatioi " 1 T. angastlB&iaa " soalproides « radians 1 Gkaili^onMU olioaoeua n " •». Tulgaris AsierioAella foniosa t» aabtilissisa " jjarrulim N •) T. •ioropuB Coeeoaeis pedieulus Oynbella mexieana HaTioula angllea « rhoHboides tt einota Haufleri •* trianeulatun tt eryptoeephala t. intermedia » yentriaoea II media H oryptoeephala •. puinila ABi^sira oralis II euspidata N n t. aiabigua Rhopalodia gibba fl •xLgua T. capltata 11 graeiUs NitBsohia loiplilbia n hunearioa " apicttlata H " T, capitnta M closterium N lanoeolata n dlBsipata H peregrine t. nenlBculus (I gracilis T. Behizonent- n pujula oidea n " T» oapitata N hungarica II rhyneooephala •. rostelleta H linearis It pale a Pinwilaria arabissooii H » T* tsaoirostris <* interrupta H 161 -

Tabls q

OrganslAa coBposiac the botton inicroflora Dea Hoinaa Rlrar, Boone County, loam. (Coatlmiad)

P^tatoaM continued Qpaea alga# mtzBohla alffioldea Badiastrtn Boryanuo " aabtllla 1 duplex <* slBplex Hantssehle asphloxya SaanedeaiBua aeumlnatus Ojaatoplaura aolea n quadrleeuda

Svrirella angueta " Uaaarla n ainuta " oTalls " orata <• Btlaerl * robuata t* si>leiidl4a " tenera « " T« nerroaa

Odoatldlua Tolgarla

Oyptopleura turgida