7006

• UCREFRP Catalog Number: 7006
• Author: Gustafson, E.
• Title: Early Development, Adult Sexual Dimorphism, and Fecundity of the Razorback Sucker,
• USFW Year: 1975
• Copyright Material: NO

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tlon 0; preUa0E:OU& spauies, hci~e ~een related to th0 decline of

X,ITuuck::n &110. OC (i<.:r endigenou3_~y'Ua.~ i. G

r .
launa from that region

since ~he earlY 19)Crs(stevens, 1938; Noffett, 1942; Dill, 1944).

Wi~h l,:l~ Gomple(;;ii.in or' iU.it-i,s D-4.w. ill 1)53, a substanchial razorback

sucker population oecarne isolated. wi thl.r.l. the reservoir. Erection

of St.:C(l impoundments h.as served. to impe..le the ups~ream spawning mi-

grations of XyrdU-:':i-len, repurL,ecl by Jora.an (13)1) and by Hubbs and

Miller (1953). In addition, fluc~uations in water leve~s beloW

these l.mpou~~drne.l1t,s .\':.1S ODservcG. La to ueseroy uevelopi11g Xyra.uche.a

CZl'ur,y'OS w/1ich wt:re deposited by sp~~'mi1..e; alults along shorelines

at dephs of less Ghan a meter.

l.a the c;.ourse of bl.'oodst;oc:'~ J.:e:.::.o',;(;1.'/ efforts, some JO.t-' Indlv-

iduals maiataineu.at the Willow cleach hatchery expired as a result

of bacter'L-,~l ini'ectio.i.1S. Pathological examinat;,o11 of these fish

;:;:l Hr. B; D. Rosenlunll ot: the USDI Fish and. Viildlife Service reveal-

cd ht;d.v,y sysl:.~mic iIlfestatlons of Pseudomonas E,E- and' Aeromonas sp.

iLLfe(:.t,ii.>4~::>. It W':lS furth8r decermiI...,cd~hat tae .bacterial agents

lf~v 01 \/',>_.i. ~j(~re .;....lreau,y preS~.L1t; ill the suc~(ers W~leL1 they were removed

[rUill ~he reservoir.

I,

.J.\Iot~ljl th.3~d.Ild.ing the Jetrlrj,dntal ecological and pathological