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<br />'157~"":::': -':'-:' '
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<br />156
<br />
<br />CALIFORNIA FISH A~L> GAME
<br />
<br />THE FISHERY OF THE LOWER COLORADO RIVER-
<br />
<br />preference, it has not kept it from inhabiting some of the muddiest sec.
<br />tions of the Colorado drainage. It has been taken from the Grand
<br />Canyon where the silt load is still extremely great, and from the .Alamo
<br />and New rivers which run chocolate-brown.2o, The collections made in
<br />1942 would lead one to believe that it has shOwn a greater degree of suc-
<br />cess in all types of Colorado River water than has any of the other game
<br />fishes.
<br />
<br />Size. In the Colorado it reaches a large size which is comparable in
<br />every way to that usually attained in its native waters, Forbes and Rich.
<br />ardson (1920) say that in Illinois" It is seldom taken of more than fiw
<br />pounds weight, aIthougnspecimensal'e occasionally seen weighing from
<br />fifteen to twenty pounds." Similar statements are given by other
<br />authors.
<br />
<br />~.aphs which have been seen make it certain that quite a number
<br />," nl:l catfish weighing 10 to 15 pounds or over have been taken in
<br />rs,-the fish which are usnally caught are muchsmaHer. During,
<br />~ survey many large catches composed entirely of fish from about
<br />,}~ches in length were seen.
<br />
<br />(f,uCtion, The smallest fish seen which could definitely be said to
<br />ally mature (adults) were two females 7.3 inches in length taken
<br />ions Dam on April 14, 1932, by E, H. Glidden. In 1942 eight
<br />:e females were seen which would have spawned in that year. These
<br />in size from 8,3 to 26 inches in length. Fourteen other females
<br />g from 1.3 to 15.0 inches in length were examined which may have
<br />~-irfiS1i:-' 'The largest female seen which it was believed was a sexll,-
<br />ature (young) fish was 10,4 inches long. - .
<br />,'e segregation of the fish examined into three classes (young or'
<br />fiire, ripening or ripe adults, spent adults) was not based on very
<br />i~r.n~ria. Those classed as ripening adults were easy to distin-
<br />\:llrossexamination of their ovaries showed them to be turgid and to
<br />~large trl1nslucent eggs. Fish whose ovaries lacked these eggs could
<br />~', ejther immature or fish which had spawned. No exact line
<br /><be drawn between these two classes in the material available. Flac-
<br />\r.the ovaries and the size of some of the fish examined made it
<br />atsome of those lacking the large eggs might have spawned.
<br />...::tbe collections were not large enough to settle this question
<br />, , roy, one can not offer an opinion as to the upper size limit at
<br />~uspecies usually becomes sexually mature in the Colorado. It
<br />yoe said that some females spawn at the small size of 7,3 inches;
<br />'. in&. size of at least 10,4 inches may possibly be reached befor~
<br />.is attained.
<br />eonly fish seen which appeared to be almost ripe (i.e" haTIng large
<br />". Qst free from the ovarian walls) were two females, 12.0 and 16.6
<br />in length, taken on April 26, 1942, at Laguna Dam. A fish in
<br />well-developed eggs were apparent was taken as early as January
<br />,!2.at Yuma. The ripening eggs from this fish (26 inches long and
<br />riTln;i'ID weight) had an average diameter of 2,5 m,m. (about one-
<br />,]ncnJ,but were still undetached, Another fish ( 8,9 inches) with
<br />,~.ed eggs of the same size was taken at Parker just four months later
<br />:TJ9, 1942) .21 'Mature but unspawned females were also seen at Lake
<br />~on May 21, 1942. The earliest date at which fish presumed to be
<br />":-w:ere seen was April 26th.
<br />neo--ril such meager data it can only be assumed that the spawning
<br />,'inthe Colorado oceurs during the spring and summer. This agrees
<br />.obsj:!rvations made in other regions. (See Adams and Hankinson,
<br />;r":-."'"
<br />~Bumber of mature (translucent) eggs produced was calculated
<br />-~~specimens.22 A fish 8.5 inches long taken on February 7, 1942,
<br />ed:approximately 1,600 eggs; another, 26 inches long, taken on
<br />)9, 1942, contained approximately 34,500 eggs,
<br />
<br />FIG, 68, Catfish fishermen at th" heau of the Alamo Canal. Jan, 1942,
<br />
<br />There is a photograph at Needles Boat Landing of a catfish eanght
<br />in Lake Havasu in 1941 and reported to weigh 22 lbs, 9 oz. Sinet' 19W
<br />the Yuma Valley Rod and Gun Club has held a "prize fish contest" dur'
<br />illg the February-April period of each year, The weights of the large~t
<br />channel catfish entered in these contests are as follows: 1940, 19 Ibs, 1~
<br />oz, ; 1941, 14 lbs. 8 oz.; 1942, 20 Ibs, 8 oz,; 1943, 16 lbs, 12 oz. (_-\.11 fish
<br />are weighed on accurate scales.) Of course, as for all fish, there are
<br />reports of some phenomenal catfish in the Colorado which-had they
<br />\reen caught-would have far exceeded these weights. While the report'
<br />of local game wardens, the accurate records of the Yuma Club and other
<br />
<br />,., Several specimens taken from the Grand Canyon in 1937 have been eX3~lin<';
<br />by the author in the collection of the United States :-;"ational Park Service at 'Jf"llu
<br />Can;-on Village,
<br />
<br />n" egg sizes based on the measurement of 200 eggs from each fish atter preser-
<br />: :1>% formalin for several months. Shira (1917) gives the size of channel
<br />:~ as :\.I;S m,m. when extruded.
<br />Samples of known percentage (by weight) were taken from three parts of the
<br />:.'the eggs counted.
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