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VANICEK AND KHAMER-SQUAWFISH AND CHUB LIFE HISTORY 203 T\III..: 6,-Percrlltagr oCCllrrellce of food ir,'ms in Colorl/llo SfJl/(/wf;sh stomachs, Grerll Rillt!r, 196,1 -1966 Total length (mm )-Squawfish Item 1.'>-25 26-50 51-JOO 101-200 201-598 --- ----------~------------- .--- Nematodes 0 0 5 0 0 Cn1stnceans Clndocern (Bosm;ua sp.) 27 14 0 0 0 Copepoda 45 14 0 0 0 I used s Ephemeroptt"Tu S Il 9 0 Nymph 0 Adult 0 0 3 9 0 Plecoplern (nymph) 0 0 5 0 0 Thysanoplera (adult) 0 S 0 0 0 ..J.-:lemiptera 0 Corixidne (ndolt) 0 0 II 18 CI)leoptcra 0 L.~r..ne 9 S 2 0 Adult 0 0 2 S 0 Trichoptera (larvae j 0 S 3 S 0 Diplera 0 ChinHl()Inidne (1IIrvae) 60 .11l 2H .5 Ccratopogullidac (Inrvae) S 14 () 0 0 Unidentified larvae 0 10 3 0 0 Unidentified adult 0 0 2 0 0 Hymenopfern (adult) F onnicidae 0 0 3 5 0 Unidentified 0 0 2 0 0 Unidentified insects 23 29 23 18 0 Fj,h Cy"r;nus carl,io 0 0 0 0 3 (;Uo rubus/a () 0 0 0 4 likJlllrf[,wn;us baltClJllu 0 0 2 0 6 IJulIl()stcus de1,Jhi,lus 0 0 () 0 I Unidentified 0 S HI 36 49 Elnpty 5 5 13 27 39 P:.rasilized (Cest",la) 0 0 II 27 65 -----------------------------------------------------------------------------------------. Tutul Jllltnber o( stomachs 22 21 62 Thirty-five percent of the roundtail stomachs examined were empty, while only 11 percent IIf the llOlIylail stllmach::! were empty. The J'Oundtail appeared to be rather opportunistic and sporadic in its feeding habits, taking fish. aquatic insects, and terrestrial insects, while the bony tail fed mainly on terrestrial insects, plant debris, and filamentous algae. No seasonal or geographic differences in diet were indicated, Tapeworms (Proleocephalw sp.) were found jn 23 perccnt of stomachs from roundtails over 200 mm, hut no tape.' worms were found in bony tail stomachs. McDonald and Dotson (1960) reported that the Colorado chub in the Flaming Gorge Reservoir basin before impoundment was largely omnivorous with its diet including, in order of importance, terrestrial insects, plant maUer, and fish. REPRODUCTION AND YEAR-CLASS STRENGTH Spawning activities of the two species had not been observed in the Green River and 22 71 liule was known of their reproductive habits in general. Intensive hut unsuccessful efforts wcrc made in this study tu locate spawning fish and their deposited eggs, Each adult fish collected was examined and was considered to he ripe if eggs or milt were shed when squeezed gently. Relative year-class strengths were estimated horn total numbers of fish taken in each year class. Colorado Squaw/ish Time of spa wning was indicated by the presence of fish in or near spawning condi- tion in several collections although spawning was not observed nor were eggs located, In 1964, a gravid female (age VII) was taken on August 4. In 1965, one ripe male (age VIII) was taken on August 1. In 1966, three ripe males (ages VIII, IX, and X), one gravid female'{age XI), and one spent. female' (age- 'VII) were' collected between June 29 and' July 4, and an additional ripe male (age'