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1,H TABLE 1 I Collections U&ed in the Growth Study _:~ , """" ! "...,".... -1 Date l! t ,:~ :;~~ From the eurw it can be seen that the small fish bave an ext.remelyl'. rapid gro\ytll from the time they arc hatdJerl in ~ray unt.il the early part' of July. G]'(.wth graduaJl~' falls off during .Jul~', and from August to~ November there is very little grc.w1h. It is during this period that the-~: stream is nearly dry. Furthermore, it will be noted that growth is~ resumed with the increase of the stream flow during November and con:fi tinues ~t a constant rate until April, when the curve again turns upl sharph. j- In each group of the foregoing fish, examinations were made of thet:- scales. The smallest fish of group 1 on which any scales were found wasi-. 21 mm. Three 16 mm. fish had no sign of scales, On the 21 mm. fish th~ scales were small, round plat.es without ridges, approximately the sam. size as the clear cent.ral area found in t.he scales of older fishes. It might be expected that a check would show on the scales of th fish of the year as a result of the slow growth during August, September and October, and the increase of growth during' No\~ember and the follow ing months. Such was not the case. In fact. there was no evidence 0 retarded growth on the scales until ~iarcll. This is probably due to th fact that duril1g August, September, and October the scale was gro . at a much greater rate than the fish. That the scale was growing very f at that time will be demonstrat.ed later in Figure 45. The evidence of slo . growth in March is most apparent on the scales of the larger fish. Scales from several hundred fish at various times throurrhout a ve gave a consistent pattern of scale growth for each year of life. The-fi annulus is formed in the spring, when a period of rapid gro-wth (widel- spaced circuli) follows the formation of the annulus. Slow gro (closely spaced circuli) follows and the time of its appearance coincid . almost exactly with the time of low water in the streams. This pattern . so consistent that in only five of over 900 specimens was it impossible - determine the age. Figure 44 illustrates a typical scale. - Since it appeared that during the first year the scales and the - had 8 different rate of growth, it would be of considerable importance, know whether this difference occurred during succeeding years. ,'" The regression of scale size and fish length is plotted in Figure The points indicated are the 8yerage fish lengths for each five units scale size. The number of measurements used to determine each point. F,GUHE H. Scalf: of ~~O-nlillinH>ter ~quawfi.!:h in its fifth - . C - February 12, 1927 }t:aJ, OJ ot~ Creek, i,"li\:ated. The dotted lines C(lnn t . d . ~II!~::: ~ ;~I:: ~]~ ~v~~~~~ ;;t~ae:]~ h 1~1 istri b~~t i o~~:):~ ~~ ci:~ ~t~~~ \~~;:ea \~~IT :~le~~ IIIl' J;,;]. were toe f _' Pb to a length of 140 mm. Beyond this point . _ .. ) ev. m num eJ' to u"e thi" tJ d- If 1 . . . \'Ilrrc!atioll b,e-'-,rnen th . f'- - me 10. t Jere ]S suffiCIent I 'c e rerrrCSSlOn 0 s' l' d fi h . \'I'J'sa. th(' U' f b ,.. . - ca e SIze an s length and ...-lce 11l1'~I'), fish r::~r~ I' l(~thb' IregWrehsslOnhs would make .the measurements for the e e la e en t p two reo"!' .'S' f fi h W"I'I' plotted i" - ,.. en 10nS 01' S up to 140 mm. Fi::III'" .ftj th~ ~i~~;ss f~~nd that there was a very close correlation. In lis!! kll;.!'th fO; the' n::l~~~ ~t~~~~. ~.~resent average seale and average \\'1" slI'lJotbed bv a" - III l\:ated. The curve below 140 mm. ,. . mO'll1g average of three. }JOTnr 4-' r 1 '''I ,.. e ,) 1J1( lcates t lat the scale appears at a fish leno-th of ab t ';;' IlJIII and that t};' . .., . . '" ou IIhollt :i~) ~m ], ':a .l~;.e I~ a w~y rapld ll1!tlal growth until the fish is "lIIalles1 'cal' 0...,.. -rT..Isda,.. ree.s ,ery well WIth the observed fact that the - ". e" as 011n on a fish '>1 . I h d \:1'.'\\' at a I' . d . - - mm. Il1 engt an that the scale li"}1 W'" .apI. rate dU~lJ1g the summer months of the first veal' when the P\lrt;(:;;af\~::'~:s;'ei~' ;~tt1e: Frotfi3~ to 160 mm. there is a' constant pro, ""'Illl' CYTC.wth i' . . e ~Ize 0 s and scale. Beyond that point the JllIiut beyond ~5l:reaSlDg.y. small in proportion t~ fish growth. At no IIl1tke it unreli bI ,m.,. hdo,":e.er, does the scale grow at such a rate as to a e ill JU gmg the growth of the fish. -,. "- 7'" -~ ......