336 



Illinois Natlral Hlstorv Survey Bulletin 



Vol. 28, Art. 2 



Firneplidles iiotatus 

 . Noturus niiiinis 

 Ethc s 1 III (I II if) r u in 

 Cyprintis caipio, young 

 JMoxostonui spp., young 

 (jfirpiotlcs spp., young 

 Ilypiiitiliuni iiif/ritaits, \oung 

 Percina maculata 

 Carpiodes cyprintis 

 Hyhoi/iinthns nnrluilis 

 Xotropis littrensis 

 Pools: deep, sluggish 

 Lepfjinis rnef/alotis 

 Alinoptcrns tloloniieui 

 . I iiihl'iplitis nipistris 

 Esox niiwricnnus 

 Eriniyzon ohlonyus 

 Kotcniif/onns crysolciicas 

 Lcpoinis hum ill 

 Pimephahs pro nichis 

 .1 pli red 0(1 cms say a n us 

 Lf porn is nun roi liirus 

 htalurus natalis 

 Ictaluriis III el as 

 Noturus f/yrinus 

 Notropis unihratilis 

 Lepomis cyanellus 

 lundulus notatus 



Species of Small Rivers 

 Riffles: sand and gravel 



Xotropis whipplei 



.} niniocrypta pellucida 



P h e nac o h i u s in ini h His 



Notropis dorsalis 

 Riffles: boulders and rubble 



Hypentcliuni nif/ricans 



Etheostoina hlennioides 



Noturus ftavus 



Notropis ruhellus 



Etluostorna zonule 

 Pools: shallow, moderate velocity 



Aioxostoma erythrurum 



P( rcinu phoxo< epliuln 



Aloxostonia macrolepidotuin 



Carpiodes velifer 



Percina caprodes 



Hyhof/nattius nuchal is 



Lepomis meijalotis 



Lepomis cyanellus 

 Pools: deep, sluggish 



Micropterus punctulatus 



Aloxostoma anisurum 



Cyprinus car pi o 



Dorosoma cepedianum 



Micropterus salmoides 



Pom ox is annularis 

 P y Iodic t is olivaris 

 Lepomis macrochirus 

 J plodinotus grunniens 

 htalurus natalis 

 htalurus melas 



Species Associated With Various 

 Ecological Factors 



From each of our cjuantitative samples, 

 the number and weight of each species 

 per 100 square yards were recorded on 

 IH.M sorting cards along with measure- 

 ments or appraisals of the following 13 

 ecological factors of the habitats: (1) 

 average depth, (2) average wndth, and 



(3) average water velocity; composition 

 of the bottom materials as percentage of 



(4) clay, (5) silt, (6) sand, (7) silt 

 ami sand, (8) gravel, and (9) rubble; 

 occurrence of (10) aquatic vegetation, 

 (11) debris, and (12) bank vegetation; 

 degree of (13) water turbidity. Each of 

 these ecological factors was assigned 

 numerical values to express the total actual 

 range of field measurements (examples: 

 depth in feet, per cent sand). 



For each value of an ecological factor 

 (for example, over bottom materials that 

 ivere 30 per cent sand), we determined: 



( 1 ) the total number of individuals of 

 each species associated with tl'.e 

 value. 



Example: 100 creek chubs taken 

 over 30 per cent sand. 



(2) the number of collections in w^hich 

 this species occurred. 



Example: Creek chubs occurred in 

 10 collections. 



(3) the total number of collections associ- 

 ated with the ecological value. 



Example : Bottom materials com- 

 posed of 30 per cent sand were 

 found in 20 collections. 



(4) the average number of fish of each 

 species found with the \alue, figured 

 by dividing (1 ) by (3). 



Example : 



100 creek ch ubs over 30% sand _ 

 20 collections over 30/o sand 



5 chubs per collection over 30% sand 



(5) the per cent of collections associated 

 with the ecological value that con- 

 tained the species, figured bv dividing 

 (2) by (3). 



