Bulletin STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION DIVISION OF THE NATURAL HISTORY SURVEY THEODORE H. PRISON, Chiej Vol. XX BULLETIN Article II A Survey of the Fishery of the Kaskaskia River WILBUR M. LUCE I'KIXTED BY AI'THORITY OF THE STATE OF ILLINOIS URBANA, ILLINOIS AUGUST, 1933 STATE OF ILLINOIS DEPARTMENT OF REGISTRATION AND EDUCATION John J. Hallihan^ Director BOARD OF NATURAL RESOURCES AND CONSERVATION John J. Hallihan, Chairman William Trelease, Biology John W. Alvord, Engineering Henry C. Cowles, Forestry Edson S. Bastin, Geology William A. Noyes, Chemistry Charles M. Thompson, Represent- ing the President of the Univer- sity of Illinois. STATE NATURAL HISTORY SURVEY DIVISION Theodore H. Frison, Chief Carroll Chouinard, Editor ILLINOIS PRINTING CO.. DANVILLE, ILL. 8710 CONTENTS PAGE Introduction 71 Hydrography 74 Personnel 80 Methods and Equipment 80 The Value of the Fishery 83 Kinds and Numbers of Mussels 86 Kinds of Fishes Caught with Various Tackle 87 Factors Affecting the Abundance of Fishes in the Kaskaskia 89 The Rate of Growth in Fishes 93 The Fishes of the Kaskaskia 94 Large Fishes 95 Small Fishes 114 Literature Cited 121 111. o CM uJ < O en in ui abiHi. > S3 to !» ID bo a ctS 10 «f-i o a o sS t O^ U -9 Jc, ILLINOIS NATURAL HISTORY SURVEY BULLETIN VOLUME XX ARTICLE II A Survey of the Fishery of the Kaskaskia River WILBUR M. LUCE INTRODUCTION In the smaller streams and rivers of Illinois the principal value of the fishes and other aquatic products is attached to hook and line fishinji and to the recreation and sport of taking fishes, with secondary importance attending commercial fishing. The Kaskaskia, or Okaw, River' is a fair representative of the secondary streams of Illinois. In this survey we have determined what kinds of fishes are present. A comparison with the collec- tions of fishes made in this stream 30 or more years ago by the late Pro- fessor S. A. Forbes and his associates shows that there has been very little alteration in the variety of kinds present. Statistics gathered by the United States Bureau of Fisheries for 1922 (Sette, 1925)- on the commercial fishery of the Kaskaskia present to the hook and line fisherman a very imperfect picture of the kinds and abund- ances of fishes in this stream. Accordingly, special efforts were made in this survey to collect those kinds which are most attractive to the sports- man, and to form some conception of their sizes and relative abundances, with any additional information readily obtained concerning their life history, growth or other features of their welfare. An attempt has been made to analyze the effect of some of the more obvious environmental factors and conditions which are known to affect the distribution and abundance of fishes. The Kaskaskia River is one of the cleaner streams of Illinois and there is little reason to believe that pollution has made any extensive inroads on the fish yield. However, at intermittent periods and at certain places, pollutional conditions do exist which either destroy fishes or force them to abandon certain regions, and destroy a large part of their food resources over wide areas. 1. See map facing this page. 2. References are to literature citations, page 121, follnwiiig. [71] 72 ILLINOIS NATURAL HISTORV SURVEY BULLETIN In the course of tliis survey, 587 of the more important fishes were tagged and released in order to learn whether or not any considerable migrations take place among these useful kinds. While no extremely large migrations have come to our notice from fishes tagged in the Kaskaskiu or any other Illinois waters, we were surprised to learn that the catfishes, and in particular the black bullhead, make rather extensive migrations covering distances 10, 20 or even 40 miles upstream within a few days or Fig. 2.—Kaskaskia River near Bondville, October, 1929. weeks. Migrations of a similar order but somewhat smaller have been found to prevail among others of our more common fishes either in the Kaskaskia or in other waters of the state. This fact leads us to believe that following such catastrophes as pollution, extreme drouth or other condi- tions which may drive the fishes out of wide areas, the reestablishment of suitable conditions is followed by rapid recovery. Within a year sufficient breeding stock will have entered the area as migrants and within two or three years the fish population will have assumed its normal aspects. This is of considerable consequence as a practical matter of conservation since it shows that restocking of our waters by such natural means goes on rapidly and under ordinary conditions makes artificial propagation and distribution of fishes in these waters unnecessary. No evidence has come to light in this survey which indicates that the fish population of the Kaskaskia is in any, sense seriously depleted, that the river is overfished, or that any of the ordinary popular remedies will be reflected by increases in fish yield. LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 73 At various times in the past decade or two considerable portions of the Kaskaskia have been open to commercial fishing. At present the entire river is closed and fishes may be taken legally only with hook and line. Indeed, it seems that the Kaskaskia as a whole is most useful as a place in which to fish with hook and line, except for the lowermost part of its course from Evansville to the mouth in Randolph county. There the stream has a width and depth not found in its upper reaches and fishes typical of the main channel of the Mississippi are found in great numbers. 5- .,*.'» ^.^'^ eo 30 MiiK Abpvc Mouth Fig. 3.—Profile of the Kaskaskia River. Spoonbill cat, channel cat, bullheads, the huge flathead cat and Fulton cat are numerous, together with still greater numbers of carp and buffalo. All of these are commercial fishes and are seldom or irregularly taken on hook and line. It is commonly known that many commercial fishes of the Mississippi River proper retreat into the mouth of the Kaskaskia during the winter months and move out again in spring. In this paper the fishes of the Kaskaskia have been taken up one by one and in the case of the larger and better known kinds points of interest and usefulness have been discussed, while the smaller, rarer and less im- portant kinds are only mentioned. In the course of this survey quantitative collections were made of the small bottom animals which are the most important constituents of the food of all kinds of larger fishes. Detailed analyses of this material and data will be presented in a later report. Material was also collected for determining the rate of growth of all the more important kinds of fishes, but this, too, can be presented more 74 ILLINOIS NATURAL HISTORY SURVEY BULLETIN effectively when material from other parts of the state is brought into comparison. It may be mentioned here that such a study of the rate of growth of the white crappie is being completed. Comparison of the total lengths in inches of white crappies for different ages in the Kaskaskia and Sangamon rivers is shown in the following tabulation. White Crappie River LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 75 that part of the profile represented by dotted lines were calculated from the railroad elevations on the base map of Illinois prepared by the Illinois State Geological Survey in cooperation with the United States Geological Survey. If we consider the top of Yankee Ridge as our starting point, the stream drops 140 feet during the first 2 miles of its course. Where it leaves the Mahomet quadrangle, at a point about 12 miles from its source, its elevation is about 670 feet—a fall of about 1^0 feet from the highest point in the headwaters. From this point to the mouth of the river the fall 'f »j1 «<> X Am Temperature— Water TCmpcrature. St IS SuUtVAM l3HtLtYviut I Co^ti^ I I fuTl I Pout 1 Cwiyli I Ijn/y i i 1 • » M II 12 1} H 19 Ifc 17 IS l> 20 Zl 22 a U a 24 i^ Z8 2? V/EtilDV , IntwATmm 3li i i 4 i i 1 • » M II 12 1} H 19 14 17 IS \f 20 Zl 22 Zi i^ H 24 2T 28 2? }0 }l i~? i A 3 -AUGUST SEPT. Fig. 4.—Air and water temperatures on the Kaskaskia in the summer of 1929. is much less, varying from a maximum of 55 feet in 18 miles through Moultrie county to the low gradient found in St. Clair county where the fall is only 10 feet in 20 miles. As a result of the stream's very low gradient and winding character, its rate of flow is quite slow after emerging from the Shelbyville moraine. Above Shelbyville, at least during periods of comparatively low water, there are stretches of quiet pools and riffles alternating with comparatively swift water, but below this point the stretches of rapid water occur less often and the stream has a slower and more nearly uniform flow. The graphs in Fig. 4 show the temperatures recorded while the field party was working on the Kaskaskia during the summer of 1929. The water temperatures were taken about 2 inches below the surface, well out in the channel of the river. The air temperatures were taken in the shade. The same thermometer was used for both. As one would expect, the graphs show that there is less variation in the water than in the air. Thus the water ranged from 69.8^^ to 86^ F. while the air ranged from 61° to 76 ILLINOIS NATURAL HISTORY SURVEY BULLETIN 95° F. The general trend is the same in both, and variations in the water are always in the same direction as, and doubtless a direct result of, varia- tions in the air. x /;qc. The water of the river is usually quite turbid, the rcolor of the sus- pended matter depending upon the nature of the soil. Above Shelbyville, where the river is draining the darker soils of the Wisconsin glaciation, the water is grayish brown when turbid; below this point, where drainage is from Illinoisan glaciation, the color is brownish yellow. Fig. 5.—Kaskaskia River at Vandalia, July, 1930. The bottom of the river is not worn down to bedrock except for about 20 miles near Shelbyville, where the bed is limestone. Throughout the first 10 miles from its source the stream has been dredged and the bottom is muddy, with little sand and gravel and with cojisiderable aquatic vegetation. For the rest of the river's length the bottom is primarily sand and gravel with very little mud, and is almost devoid of aquatic and shore- line vegetation. Wherever.riffl.es occur in Douglas, Coles, Moultrie and Shelby counties, the bottom is composed of coarse pebbles and glacial boulders of various sizes. Through St. Clair and Randolph counties during periods of low water the bottom is often covered with a layer of fine silt as much as a foot deep, which overlays a bed of hard packed sand and gravel and which is frequently scoured away during periods of flood. In Champaign and Douglas counties the river has developed no extensive valley, and its bed is not much lower than the surrounding plain. LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 77 Through Moultrie and Shelby counties the valley varies in width from 1/8 rnile to 1 Yo miles, the topography being rather rough throughout this region. Where the river emerges from the Shelbyville moraine its valley widens to about 3 miles. This width is maintained as far as New Athens in St. Clair county, except at Carlyle in Clinton county where the valley narrows to about 1 mile for a short distance. From New Athens to the mouth the valley has an average width of 1 mile. Table I. — Monthly Discharge of the Kaskaskia River at Vandalia. Drain- age Area 1,980 Square Miles. 78 ILLINOIS NATURAL HISTORY SURVEY BULLETIN that makes tile laying economically possible. Artificial drainage increases the rapidity of the run-off. In the greater part of the basin, which consists of Illinoisan and earlier drifts, the soil is made up of loams, silts and loess. Here the subsoil is a compact clay, which condition also results in a very quick run-ofiF. Consequently the river is subject to large and rapid varia- Table II. — Monthly Discharge of the Kaskaskia River at New Athens. Drainage Area 5,220 Square Miles. LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 79 sible of passage, e\'en by rowboat. In the spring of 1930 a flood washed out this muddy delta. The floodplain of the Kaskaskia, after the river has emerged from the Shelbyville moraine, is dotted with small overflow lakes and sloughs. These are especially numerous through Bond, Clinton, Washington and St. Clair counties. None of them are extensive in area and their total combined area is not large. Fig. 6.—Kaskaskia River at Carlyle, July, 1930. In the lower Kaskaskia basin there are numerous ponds on the sur- rounding high lands. Individually, these are usually less than an acre in extent but many are permanent, as they contained water throughout the very dry summer of 1930. The main tributaries of the Kaskaskia are Richland, Silver and Shoal creeks to the westward, and Crooked Creek to the eastward. Other than these, there are numerous smaller tributary creeks. Fig. 1. Perhaps one of the most interesting facts in connection with the hydrog- raphy of the Kaskaskia is the stealing of the lower part of the Kaskaskia valley by the Mississippi. The old mouth of the Kaskaskia was near the town of Chester, at the southern end of what is now Kaskaskia Island, about 7 miles below the present mouth of the river. On April 18, 1881, the Mississippi broke through the neck of land at the bend 2 miles above the old town of Kaskaskia. There was at this point a difference of 8 feet in the level of the two rivers, the Kaskaskia being the lower. The result was that the diverted water of the Mississippi soon cut a channel into the Kaskaskia 80 ILLINOIS NATURAL HISTORY SURVEY BULLETIN and appropriated the lower 7 miles of its bed. This new channel was origin- ally but 500 to 600 feet wide, so that at first it carried only a small part of the volume of the Mississippi. Gradually the new channel became widened and deepened until finally the old channel filled up, and at times of low water it is now possible to walk dry-shod from Missouri to Kaskaskia Island. Since the east bank of the Kaskaskia consists of the limestone cliffs that form the bluffs of the Mississippi valley, in widening the new channel the river cut away the softer alluvial west bank and approached the site of the historic town of Kaskaskia. This town had been settled about the year 1700 and had played an important part in the early history of Illinois, as it was the first capital of the state. The town was not destroyed immediately, but the Mississippi in widening its new channel cut away the soil so that Kaskaskia's buildings and improvements gradually disappeared in the bed of the river during the years 1886-1909. Only a small corner of the original town site now remains. PERSONNEL Field work on the Kaskaskia was done mainly during the summers of 1928 and 1929 and early in the spring of 1930. During the summer of 1928 Dr. David H. Thompson and Mr. Francis D. Hunt made a study of the headwaters of the Kaskaskia as part of the field work for a report on the fishes of Champaign county. During the summer of 1929 Dr. Willard F. Stanley and the writer conducted field studies on the Kaskaskia from Sulli- van to the mouth of the river. In the early spring of 1930 Mr. Hunt made further field observations near the mouth of the river. Occasional observa- tions were made at various points during the summer of 1930 by several staff members. Identification of the minnow collections was made by Mr. Hunt and checked by Mr. R. E. Richardson. The plankton identifications and estimates were made by Dr. Samuel Eddy. The entire project has been under the close supervision of Dr. Thompson and any value which it may have is largely due to his guidance. The study was begun under the general supervision of the late Professor S. A. Forbes, formerly chief of the State Natural History Survey, and has been continued under Dr. T. H. Frison, his successor. METHODS AND EQUIPMENT The general plan of the field work in the summer of 1929 was to make collections and observations at intervals of 10 to 20 miles through- out the course of the river. Temporary headquarters were established for periods of three to five days at each of the following places: Sullivan, Shelbyville, Cowden, Vandalia, Keyesport, Carlyle, Venedy Station, New Athens and Reilly Lake. LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 81 For transportation the field party used a half-ton truck with a trailer carrying a 16-foot flat-bottomed skiff. Where depth of the water allowed, an outboard motor was used to propel the boat, but elsewhere oars were used because the stage of water was so low and there were so many bars and snags in the river that the outboard motor was of little use. The field party carried the following equipment: a canvas tent, 6X8 feet; three 30- inch, 1-inch-mesh hoop nets with 5-foot wings; a "common sense" minnow Fig. 7.—Kaskaskia River at New Athens, July, 1930. seine, 1/6-inch mesh, 4X12 feet; a 1-inch-mesh trammel net, 6X75 feet; a bottom-sampling outfit consisting of a Peterson dredge, a circular sieve (12 inches in diameter, with 40 meshes to the inch) and a water-tight wooden box (20 inches square and 3 inches deep) ; a 14-quart galvanized iron pail ; a galvanized iron washtub ; a plankton-sampling outfit consisting of a piece of No. 20 silk bolting cloth, a 1 -liter dipper and a glass funnel; an aquatic dip net with 5-foot handle ; two 250-foot trot-lines with 100 snells and 3/0 hooks; a thermometer in a wooden case; a dairy balance with dial graduated to tenths of a pound ; a fish measuring board attached to the balance ; Monel metal fish tags, sizes 2 and 3, each bearing a serial number on one side and the initials INHS on the other; tongs for affixing the tags; a supply of bottles and jars of assorted sizes, together with labels, alcohol and formalin; and a leather notebook filled with 5 X 8-inch cards bearing serial accession numbers. The general procedure of work at each place was as follows. As soon 82 ILLINOIS NATURAL HISTORY SURVEY BULLETIN as a suitable place was found on the river bank, the equipment was un- loaded, the tent pitched, the boat launched and the hoop nets set in likel}' situations, since the main object was to catch as many fishes as possible. Temperature of water and air were taken and recorded three times daily. The hoop nets were raised twice daily and the fishes removed from them into a tub of water and taken to the bank where the weighing and measur- ing apparatus was set up. Each kind of fish, its length from tip of snout to base of caudal fin and its weight to the nearest twentieth of a pound were recorded in the notebook, together with length of time the net had been set, date and description of environmental conditions. About ten scales were taken from the left side between the lateral line and the dorsal fin of each of the scaled fishes and were placed in a small manila envelope. On the out- side of the envelope were recorded the notebook accession number, the tag number, the name of the stream, the location, date, kind of fish, its length and weight. The fish was then tagged near the base of the caudal fin, on the dorsal edge, and returned to the stream. The catching, measuring and tag- ging of the fishes taken in the hoop nets consumed the greater part of the time at each stop along the river. A record was also kept of turtles and other animals in the hoop nets. Since certain kinds of fishes avoid small-meshed hoop nets, other methods were also employed. A trammel net was occasionally dragged as a seine, or set and the fishes driven into it. On account of the number of snags and other obstructions in the Kaskaskia, its use as a seine was not satis- factory, few fishes being caught. Trot-lines were also set across stream, with about 50 hooks to the line. Crayfish, minnows or soaked corn were used for bait. The trot-lines were quite satisfactory for catching carp, which avoid hoop nets of small mesh during periods of clear water. Some catfish were also caught by this method. Samples of small fishes were taken with a minnow seine, dragged over an estimated area of 15 square yards to each haul. The entire sample was killed in formalin, transferred to a cheesecloth sack, labeled and stored in a keg of formalin. Identification of the minnows was made later in the laboratory. Samples of the bottom fauna were taken in as many different kinds of bottom as could be found in each vicinity. A Petersen dredge was used for taking samples in mud, gravel and sand bottoms. Where the bottom consisted of pebbles or rocks and the dredge could not be used, the organ- isms were rinsed and picked off the rocks by hand. The samples were pre- served and sent to the laboratory for identification. A plankton sample was taken at each stop along the river by straining 20 liters of water from midstream through No. 20 silk bolting cloth. These collections were preserved in 80 per cent alcohol and examined later in the laboratory. LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 83 A sample of the fresh-water mussels was taken at each place visited. These usually were taken by hand, as all other methods were found to be unsatisfactory, and the shells were preserved and taken to the laboratory for identification. THE VALUE OF THE FISHERY Principal sources of information on the fishery of the Kaskaskia, or Okaw, River are the survey made by Forbes and Richardson for "The Fishes of Illinois," published in 1909; a local survey near Charleston, Illi- nois, made by Hankinson (1913) ; statistics compiled by the United States Bureau of Fisheries (Sette, 1925) ; and a detailed study of the distribution and abundance of fishes in Champaign county (Thompson and Hunt 1930). The first two of these sources show the kinds of fishes found in the Kaskaskia and give notes on their habitat relationships, life cycles and gen- eral abundance, but afford little information for a comparison with other streams of the state from the standpoint of fish yield. The statistics of the United States Bureau of Fisheries show the value of the commercial fishery supported by each stream s)'stem. The latest statistics, those for the year 1922, indicate in a general way the relative importance of the main rivers of the state as follows. River 84 ILLINOIS NATURAL HISTORY SURVEY BULLETIN According to this criterion the Kaskaskia ranks eighth among the rivers of the state. At the time this census was taken commercial fishing in the Kaskaskia basin was limited to the main channel from Covington bridge to the mouth. This includes the course of the stream across Randolph, St. Clair, and about one-half of Washington, counties. Up to 1915 the entire river was open to commercial fishing. The history of its status since that time is out- lined in the following records obtained from the office of the State Depart- ment of Conservation. Record of Fish Preserve Orders Issued in Connection WITH the Kaskaskia River. Jan. 14, 1915 Kaskaskia River and tributaries made a fish preserve. Apr. 12, 1916 Kaskaskia River opened to commercial fishing from Carlyle to confluence with the Mississippi (but all tributaries remain closed). May 31, 1921 Kaskaskia River and tributaries from Carlyle to Covington bridge made a fish preserve. Sept. 15, 1927 Kaskaskia River and tributaries opened to com- mercial fishing in Fayette, Moultrie and Shelby counties. June 5, 1928 Main channel of Kaskaskia River opened to net fishing, from the point where said river crosses the dividing line between Fayette and Clinton coun- ties, south and southwest to the Covington bridge between Clinton and Washington counties,— all tributaries in said section of the river to remain preserves. Oct. 1, 1930 Kaskaskia River and all tributaries made a fish preserve, As shown in Table III, the bulk of the catch of fish in 1922 was carp and buffalo, together totalling 16,800 pounds and valued at $1,835. Catfish and bullheads, weighing together 7,300 pounds, were valued at $1,245. The drum, or sheepshead, contributed 5,200 pounds, worth $640. Mussel shells and pearls, however, almost equalled fish in money value, compris- ing 43.6 per cent of the total commercial fishery in that year. Perhaps a greater asset of the Kaskaskia consists of those intangible benefits accruing to health and enjoyment which result from use of the stream as a place of recreation. Throughout most of its length the river is large enough to afford ample opportunity for boating and swimming as well as angling. Numbers of fishing clubs have camps along the middle LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 85 reaches of the stream. These camps are especially numerous on the flood- bottom lakes in Clinton, Washington and St. Clair counties, but the river is visited at other points also by many people. At the time this survey was being made on the Kaskaskia the Natural History Survey was also carrying on a similar survey of the Sangamon River. Since the same methods of study were used in both systems, we Table III. — The Commercial Fishery of the Kaskaskia River for 1922.* 86 ILLINOIS NATURAL HISTORY SURVEY BULLETIN KINDS AND NUMBERS OF MUSSELS Five general collections of mussels were made by hand at well dis- tributed points on the Kaskaskia, with the various kinds appearing in the numbers shown in Table IV. Table IV. — Kinds and Numbers of Mussels Taken in the Kaskaskia River FROM July 30 to September 1, 1929. UNIONINAE ^uadrula lachrymosa (Lea) Maple Leaf. ^uadrula pustulosa (Lea) Pimpleback. . Tritogonia tuberculata (Barnes) Buckhorn.. . . Megalonais gigantea (Barnes) Washboard . Amblema rariplicata (Lamarck) Three Ridge Amblema costata (Rafinesque) Three Ridge Fusconaia flava (Rafinesque) Pig Toe Pleiirobema catillus (Conrad) Elliptio dilatatus (Rafinesque) Ladyfinger. . ANODONTINAE Strophitus j-ugosus (Swainson) Squawfoot. . Anodonta grandis near var. plana (Lea).Papershell. . Arcidens conjragosus (Say) Rockshell. . . Alasmidonta marginata (Say) Deerfoot . . . Lasmigona costata (Rafinesque) Fluted Shell , Lasmigona complanata (Barnes) Heelsplitter . LAMPSILINAE Obliquaria reflexa Rafinesque Truncilla truncata Rafinesque Proptera alata (Say) Leptodea fragilis (Rafinesque) Actinonais carinata (Barnes) Mucket Ligumia recta var. /aZ/jj/wa (Rafinesque) Butterfly Lampsilis ventricosa (Barnes) Pocketbook Lampsilis siliquoidea (Barnes) Fat Mucket Lampsilis anodontoides (Lea) Lampsilis fallacoisa (Smith) Slough Sandshell Total < > 2 2 26 15 8 5 1 16 11 12 1 5 H ei O b CO (d >• U 1 1 1 19 17 7 10 < 11 12 11 10 29 < H O 4 25 22 11 13 17 18 17 7 7 1 2 1 3 10 1 1 12 54 43 1 32 23 4 26 355 LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 87 KINDS OF FISHES CAUGHT WITH VARIOUS TACKLE Table V presents the hoop-net catches in the Kaskaskia River. The percentages in the last column of the table are summarized in Table VI and show that the hoop net catches consist predominantly of a few kinds of fishes. Thus the catfishes and bullheads make up 61 per cent of the entire catch, the sunfishes 28 per cent and all other kinds together the remaining 1 1 per cent. The high percentage of catfishes may be due to Table V. — Fishes Taken by Hoop Nets, Kaskaskia River, 1929-1930. 88 ILLINOIS NATURAL HISTORY SURVEY BULLETIN their seeking the hoop nets as places of concealment. Sunfish likewise seek concealment in brush and around stones and may also enter the hoop nets for the same reason. Suckers, carp and buffalo, being active and strong swimmers and seeking open waters as a rule, are rarely caught in small- mesh hoop nets. Table VI shows percentages of the different kinds of larger fishes caught by various kinds of tackle. The second column of this table shows the fishes caught by means of a trammel net. Though the total number caught by this method was very small, the proportion of the various kinds of fishes, even in such small numbers, indicates a marked contrast to the catch by hoop nets. More than half the trammel-net catch consists of suckers, carp and buffalo—the kinds that ordinarily avoid hoop nets. Sun- fishes make up a much smaller percentage, and catfishes, which represented the largest percentage of the hoop-net catch, were not taken at all in the trammel net. Trot-line catches were so small as to lack significance except for the 13 carp, which were taken on soaked corn. Table VI. — Comparison of Numbers and Kinds of Larger Fishes Taken with Different Kinds of Tackle. LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 89 FACTORS AFFECTING THE ABUNDANCE OF FISHES IN THE KASKASKIA Since one of the aims of this reconnaissance of the Kaskaskia River was to obtain information on its fitness for the production of fishes, some general observations were made on the conditions in the stream as a basis for comparisons with other streams in Illinois. Bottom.—The small bottom animals constitute the most important source of food fishes in this stream as well as in most of the other, larger Illinois streams. Rather extensive collections of bottom fauna are being worked over and a full account of their kinds and amounts will be included in a later report. Superficial inspection of the organisms found in the samples indicates that they occur in amounts common to Illinois streams uf this size. The prevailing kind of bottom in the Kaskaskia is sand and Table VI. — Contd. Comparison of Numbers and Kinds of Larger Fishes Taken with Different Kinds of Tackle. CARP and SUCKERS pAiropean carp Red-mouth buffalo Mongrel buffalo 90 ILLINOIS NATURAL HISTORY SURVEY BULLETIN 2;ravel. Exhaustive studies of the amounts of small bottom animals avail- able as fish food on rock, gravel, sand, and mud bottoms have shown that sand is least productive, while gravel may be of intermediate or of superior productivity. Plankton.—The few plankton collections taken in July and August, 1929, seem to show that plankton is of very slight importance as a source of fish food in the main stream. Practically no plankton organisms were found in the collections except in the one taken just above the mouth Fig. 8.—Kaskaskia River at Evansville, July, 1930. of the river, and even this collection contained only 1 1 species, none of which was very abundant. Vegetation.—Streams which have considerable amounts of submerged aquatic vegetation are quite commonly found to be our heaviest producers of fish. Such vegetation, besides serving directly as food for fish, provides favorable situations for the production of large amounts of small animal life which serve as fish food. Such vegetation also provides cover and pro- tection for many kinds of young fishes. Other studies of the Illinois Natural History Survey have shown that the high fish productivity of the Illinois River is intimately associated with the wide areas of connecting bottomland lakes and sloughs. Along the course of the Kaskaskia through Bond, Clinton, Washington and St. Clair counties there are numerous floodplain lakes and sloughs, but the total area of these is so small that it is not likely that they materially affect the yield of fishes. The submerged LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 91 aquatic vegetation of the Kaskaskia system is limited to the smaller head- water streams. The factors which seem to determine the presence or absence of submerged aquatic vegetation in Illinois streams are (1) turbidity, (2) nutritive substances brought in from the soils of the drainage basin and (3) constancy of flow. The turbidity of the Kaskaskia throughout most of its length is so great that light probably cannot penetrate the water sufficiently to allow the growth of submerged vegetation. Scarcity of nutritive sub- stances for plants from the less fertile soils of the area covered by the lUinoisan glaciation may have something to do with the lack of vegetation. The water level in the Kaskaskia is subject to such variations that plants are either drowned or left stranded. Enemies.—All game fishes feed for the most part upon minnows and other small fishes. Our minnow-seine collections show that there is a plenti- ful supply of this kind of food throughout the Kaskaskia River and that in number of minnows per square yard of water it compares favorably with other rivers of the state. Natural enemies of fishes in the Kaskaskia appear to be of the same kinds and numbers as in other streams of the state, except for sporadic depredations of the lamprey, which will be described later. Thirty-two turtles were taken in the hoop nets during this survey, a number of which were large snapping turtles which commonly devour several fishes each day. Herons, kingfishers and other water birds which feed almost ex- clusively on fishes were noticed at many places. Minks, otters, muskrats and raccoons also take their toll of fish life. Fishing.—From 1916 to 1930 commercial fishing was permitted in the lower reaches of the Kaskaskia. As shown by the reports of the United States Bureau of Fisheries (Sette, 1925), the important commercial kinds taken were carp, buffalo, catfish and sheepshead. Since buffalo and certain other suckers are rarely caught with hook and line their removal with nets and seines does not materially affect hook and line fishing. Commercial fishing may, however, reduce the numbers of carp, catfish and sheepshead available to hook and line fishermen. While bass, crappie and sunfish are supposed to be returned to the water when taken with commercial tackle, the temptation to keep these game fishes is very often too great. Continued operation of trot-lines may have some effect in lowering the numbers of certain kinds of fishes in the stream. During our survey we encountered several men who were making their living by catching sheepshead and catfish with trot-lines. One of these fishermen reported catches of 120 channel cat in a single night as not uncommon with the amount of tackle that he alone used. Disease.—Practically all of the fishes taken in the course of this study appeared to be clean and healthy. This does not indicate, however, that 92 ILLINOIS NATURAL HISTORY SURVEY BULLETIN disease is not an important factor affecting the abundance of fishes in the Kaskaskia, just as in other streams, since there is a wide variety of diseases which probably take a small but steady toll of fishes, with only an occasional outbreak which may kill off large enough numbers to be noticed. Dead fishes are quickly devoured by scavengers both in water and on land, and diseased or injured fishes with slow or erratic movements are easily caught by predators. Fig. 9.—Kaskaskia River 2 miles above the mouth, July, 1930. Pollution.—Finally, abundance of fishes is influenced by the amount and kind of pollution which a stream has to bear. The sewage load of the Kaskaskia, or Okaw, is small and has little effect except during periods of low water, when some stretches, especially in summer, may become heavily polluted. For example, a septic condition existed below Carlyle in July and August of 1930. The untreated domestic sewage which goes into the river at Carlyle is augmented by wastes from a strawboard factory and a milk plant. As a result of this pollution, for a distance of at least 25 miles down- stream there was no dissolved oxygen in the water. Thousands of fishes were killed, and all the bottom animals, such as mussels and snails, must have perished also. The water was black, a layer of black sludge several inches thick covered the bottom and a strongly putrescent odor was ap- parent, even at some distance from the stream. Normally this, section of the river is a very productive one^- -^snart ':a zc About 100,000 people live in the Kaskaskia basin in towns and cities LUCE: SURVEY OF THE KASKASKIA RIVER FISHERY 93 8 7 6 - of more than 500 population. The river receives untreated sewage from about 17,000 of these people and effluent from treatment plants in cities representing a population of 65,000. A remainder of some 20,000 persons resides in cities and towns with no sewer systems (Buswell, 1927). Since the Kaskaskia basin con- sists predominantly of agricultural lands, without large industrial centers, the chief industrial wastes received by the river are such as result from treatment of agricul- tural products, particularly wastes from milk products plants and strawboard factories. In the south- ern part of the river basin there is considerable coal mining and a few limited areas which produce oil, but pumpage from these mines and wells is believed to have negligible effect on the river. i - fi 5 ft 6 it Lenqth. in inch*s Fig. 10.—Age groups of rock bass. THE RATE OF GROWTH IN FISHES 11 a a- » a- u- a- Ltnqfh in Inehu -Age groups of channel cat.Fig. 11 tinctly and are presented in Figs. 10, 11 and 12 Since most fishes spawn in a certain restricted season of the year and since the young grow at approximately the same rate, the different age groups can often be recognized. If the lengths of a con- siderable number of individuals of the same species taken from one area in a short period of time are plotted in the form of a frequency curve, these groups appear as humps in the curve. During the course of our study, data on the lengths of several species of fishes were ob- tained. These measurements were made from the tip of the snout to the base of the caudal fin. The data for rock bass, channel cat and mud cat show these age groups most dis- 94 ILLINOIS NATURAL HISTORY SURVEY BULLETIN Figure 10 presents graphically the lengths of 19 rock bass. These measurements fall into two well separated groups, each representing a year class. One group, probably two years old, varies from 4^^ to 514 inches with a mode at 5 inches, while the other group varies from 6 to 714 inches with a mode at 6I/2 inches and is made up presumably of three-year old fish. In Fig. 11, which summarizes the data for 88 channel cat, three fairly well defined groups appear, presumably representing fishes two, three and 19 ZO Tl H Z9 «4 ZS ZS Length in inche