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<br />-158
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<br />CALIFOR:!\'1,A FISH A.."<D GAME
<br />
<br />Food. The stomachs of 72 channel catfish (3.1 to 26 inches in length)
<br />were examined but only 43 of these contained food. The .results of a
<br />quantitative study of stomachs from 38 small catfish taken, ,nom a
<br />drained irrigation canal iu the Imperial Valley is shown in Table 3,
<br />Examination of 5 other stomachs containing food from fish 6,5 to 16.1;
<br />inches in length taken from other parts of the Colorado River district in
<br />early 1942 showed that substantial quantities of aquatic plants (mainl:
<br />N ajas) , aud backswimmers were also consumed. One fish, 7.4 inche"
<br />lorig,contaili.eda small bluegill.' The largest fisht16.~.iMhes::!ong"
<br />, containing food had its st{)mach packed with fragments of bulrush.
<br />From these studies and the work of other investigators it may be
<br />concluded that the channel catfish is rather om~.livorous. The literature
<br />indicates that almost any available food organisms except possibly
<br />planktonic forms--large or small, alive or dead, plant or animal-are
<br />utilized. (See: the bibliography in Adams and Hankinson, 1928:
<br />:McCormick, 1940; Rice, 1941.) Although it is knov;n to be predaceoll"
<br />on other fishes, its piscivorous habits do not appear to be as highly
<br />developed as those or the other major game fish of the river, the large.
<br />mouth bass. Fish were found in but two stomachs from the Colorado:
<br />fragments of a small unidentified species, and a bluegill 1.2 inches long,
<br />Since most of the catfish examined were of small size it might be
<br />argued that these had not yet attained piscivorous habits. However,
<br />McCormick (1940) found even fairly large channel catfish (about 13.4
<br />to 20 inches) from Reelfoot Lake to be eating but little fish. Trichoptera
<br />and chironomids comprised most of their animal foods. The rather
<br />high content of plant foods found in stomachs is of interest, and both
<br />small and large fish are apparently quite efficient in making use of dea,l
<br />organic matter. About 15 per cent of the food of young fish 0,8 to ~T3
<br />inches was found to be "ooze and debris" by Shira (1917). Table:3
<br />shows that this is also an important constituent of the food of smnl1
<br />channel catfish in the Imperial Valley.
<br />
<br />TABLE 3
<br />
<br />The food of 38 small channel catfish taken f~om West Main Dit.ch, Imperial
<br />Valley, Califo~nia. when d~ained on Feb~ua~y 7, 1942. Ave~age length 6.1
<br />inches (~ange. 3.1-10.6 inches). Total volume of stomach contents 9.034
<br />c.c. (Forty stomachs we~e examined; two we~e empty.)
<br />
<br />Per cent of stomach,
<br />containing
<br />organism
<br />
<br />Per reli of
<br />total rc,lullle
<br />
<br />ClaBB of food organi~1Il
<br />
<br />Filamentous green nlgae______________________
<br />Higher plants (mainly terrestrial) --- ----------
<br />
<br />lsopoda ______________________________________
<br />Mayfly nymphs (Ephemerida) ----------- -------
<br />
<br />Odonata* ____________________________________
<br />Caddisfly~arvae (Trichoptera) -----------------
<br />Midge larvae (Chironomidae) ------------------
<br />Terrestrial in~ctl; and spider5_______,.___________
<br />Fish (unidentified) ----------------------------
<br />Ooze (organic detritus, sand) --------------------
<br />
<br />Bird's foot _____:._____________________________
<br />
<br />2,63
<br />21.05
<br />2,63
<br />2,63
<br />39.47
<br />47,36
<br />89,47
<br />36,84
<br />2,63
<br />31.57
<br />2,63
<br />
<br />4.3
<br />10.4
<br />1.1
<br />0,3
<br />11,3
<br />5,3
<br />16,0
<br />4.1
<br />lIP
<br />21),\)
<br />10,\)
<br />
<br />* All damseltl)' nymphs except 0.08 C,c. dragontly nymph In 1 fish,
<br />
<br />THE FISHERY OF TEE LOWER COLORADO RIVER
<br />
<br />159
<br />
<br />lace in the Fishery. The channel catfish fulfills three of the criteria
<br />y applied to game fish, being a good fighter, having a tasty flavor,
<br />. dilaving at least some susceptibility to the attraction of artificial lures.
<br />'is true that most of them are caught on 'bait, but flies, spinners and
<br />ugs can also be used with some success.
<br />At some places (as at Lake Havastl or Martinez Lake) the catch of
<br />may exceed that of catfish, but in the area as a whole, including the
<br />ificial waterways, it is believed that the cateh of channel catfish exceeds
<br />~.Qtb. numbers and pounds that of any other fish. There are several
<br />---us for this: abundance of fish iri different types of water andin-'
<br />c- y accessible ones; ease of capture on simple equipment; preference
<br />'an article of diet.
<br />'.As has already been mentioned, this fish has an important role as a
<br />'enger and as a utilizer of foods not taken readily by some of the
<br />r'game fishes, It is possible that its. predation has, in part, been
<br />usible for the d~letion of native fishes.
<br />
<br />bullhead, AftUiurus .at,,zu (Le Sueur)D
<br />
<br />Names. Mudeat, yellowbelly, "native" bullhead.
<br />
<br />'nitio-n Characters. Rounded tail; whitish chin barbels; 24-27 anal
<br />; yellow coloration.
<br />
<br />ribution; .Abundance; Habitat. Its origin in the river is unknown,
<br />e presence of this or some other species of Ameiurus is believed to
<br />ate that of the channel catfish. 1-Iany of the residents have con-
<br />eiurus to be native.
<br />e reports of fishermen (if their identification is correct) indicate
<br />this species is the commonest bullhead in the lower river. However,
<br />six specimens were seen during the 1942 survey. Three of these
<br />from Haugbtelin Lake; one was seen at I.1ake Havasu; one in an
<br />tion ditch near Bl:rthe; one at the Imperial State Game Refuge on
<br />amo River, There appear to be no authentic records for its presence
<br />. ornia outside of the Colorado River drainage,
<br />Mr. W, C. Blewett (letter of April 9, 1944) informs me that it thrives
<br />:m backwaters and sloughs as in the Palo Verde region. Several
<br />.ents of Blythe and Needles state that it is fairly common in such
<br />'. :,.It in no way approaches the abundance of the channel catfish,
<br />er.
<br />
<br />\~Those seen ranged from 7,0 to 11,4 inches in length. Forbes and
<br />." on (1920) give the length of this species as 12 to 18 inches, but
<br />t it is not often found over 12 inches in length.
<br />
<br />",cHon. All of the specimens examined were taken between J anu-
<br />,and February 25, 1942. They were all mature females which
<br />,,;'yet spawned. A spawning season in the spring or early summer
<br />.t~. Authors cited by Adams and Hankinson (1928) give May
<br />, e as the spawning season in the east a~d middle west.
<br />
<br />',7 Three stomachs were examined; one contained food. This:fish
<br />~')hes) taken in a gill-net from HaughtelinLake on January 30th
<br />.'-.^~- '..
<br />
<br />.0- of the specimens collected. a female 10.6 inches In length taken In a gill-net
<br />Lake, January 30. 1942. has been identified as the northern yellow bull-
<br />......._.. _~.~u,. "ntnli.<l (Le Sueur) by Dr. Carl L, Hubbs,
<br />
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