UNITED STATES DEPARTMENT OF THE INTERIOR Walter J. Hickel, Secretary Fred J . Russell, Under Secretary Leslie L. Glasgow, Assistant Secretary for Fish and Wildlife and Parks U.S. FISH AND WILDLIFE SERVICE Charles H. Meacham, Commissioner BUREA U OF COMMERCIAL FISHERIES Philip M. Roedel, Director Alaska's Fishery Resources The Chum Salmon By THEODOHE R. MERRELL, JR. Fishery L eaflet 632 Washington, D.C. June 19 70 CONTENTS Page Intro duction. • . • . • . • • . 1 G eographic distribution . • • •• • . • • . 1 Life his tory . • . • . • • • . • . • . • . 2 E c onoITlic iITlp ortance ............... 5 Selected references . • . 7 iii Alaska's Fishery Resources - The Chum Salmon By THEODORE R . MERRELL , JR. , Fish ry Biologist Bure au of C orrunercial Fisheries Biological Laboratory Auke Bay , Alaska 9982 1 ABSTRACT The churn salmon, Oncorhynchus keta, i s the most wid Iy distribut d and second most abundant o f the five P acific salmon. It is one of Alaska's valuable fishery r esources . Churn salmon spawn in late summer and fall -- s me in small stre ams n ear th o c ean and oth ers in larg rivers in which they trav I as far as 1, 5 00 miles from the ocean . The young hatch in midwinter but stay in he stream grav 1 until spring , when they emerg and migrate to sea . They spend 2 to 4 years in the sea and weigh about 10 pounds when they return t') spawn and die in their native stream . M ost churn salmon are taken in purse seines and arc canned; hundr e d s of tho usands are caught in gill nets and fish wheels f or human and d og f ood . Thi s fishe r y is mostly in the large rivers that run into the Berin~ and Chukchi S eas of northern Alaska . Little biological research has been d nl' on churn salmon , so l ess is known about them than any other Pacific salm n . I TROD1:CTION that gave thenl the generic nanle Oncorh)nc.hus, which means hooked snout. Chwn sal mon are o n e of Alaska's inlportant ish e ry r esources , although they are not as ighly egarded as the other four Pacific salm ­ GEOGH.\PHIC DISTRI 13 l' TIO' n --pink , O. gorbusch a; sockeye, O . nerka; h inook, O-:-t s hawytscha; and coho, O. k~ . Chunl salnlon are th, nlu"t \" idel), dl"t rib .teU : hwn salmon are mor e difficult to catch, are of the five Pacific salmon species and tll'Sl( nd \ortl l ess per p ound, and are l ess palatable nlost abundant. They ( ccur in stn'anl In,' rth han th e other species . One of the reasons for America along the Tor h Pac.iflL ( a ... • fr II he low appeal of canned churn salmon is the pale Oregon tu the Arctic Oc l'an c. ld ~t ! \ I .1, ' o lor of the meat. and in Asia fronl he Arctic CCd" f Sib qa ' The col o r of flesh and the appearance of n orthern Japan. Scienti -t - ith.> L'llI'l'd : hum salmonchangeas they approach nlaturity . Canada, and Japan, who w(lrk tc>~ e her 'I1r I n While they are in the ocean, their flesh is rich the International. Turth PaL ifiL Fill 'r,I C In­ red, butas they approach the spawnin streanls , nlission, ha\ e sho\\ n b) tag in~ l' p' rln t'n it pales to a light pink. At this time they also that Alaska ChWl1 salnlUn n l'r.1 'h lose their general silvery col or, and vertical th 'orth Pacific Ocean and B('rm purpl e -black and dull red streaks begin to ap­ nlingle in sonle drea" \\lth Lhurn In p ar o n th ir sides; as with many fish the color Asian streanlS. The A -idn ~tr c hang s are more pronounced in the nlale than abou four tinle s a - I an\ C. n IT the f mal . The maturing mal also develops year a" he. \ rth An ",r I an re 111 hooked jaw and enornlously enlarged front Anlur Ri\'\~r ,Sib rld hd te th as h ne 1'5 th spa\' nin stream (fig. 1). any river in \, rlu. Ill. 1 The e t eth are us d to threaten and bite other arc n10 1 nUl r c..l in rt:dl1 rnal s who orne t oo close on th spawnin ea"tern Pan andle, C 0 Inl ., round. The hooked ja is comnl0n to all five Arc. IL rib 1 rl ., f h B rln sp of Pa Hi salnl0n and is the haracter tel.::' . the B ring Sea. Chum sal mon b ury their e in the g rav I in th late summe r or fall; I all o ther Pacific sal mon, the y die soon af' s pawning . Th young, which are c alled "h until th yareabout l-lflinches l o ng, hal in midwinter , emer g the fo llowing s pring, a m i g r ate directly t o sea . They grow rapidly thea ean, andafter2. t04years returntospa in th· stream wher they wer e hatched. September of their first summer, they art t (J inches l ong . When mature, most c ht salmon are 3 to 5 years o ld, weigh 8 to pounds, and are about 30 inches l o ng; mal an usually larger than females (fig . l ). A rl'sumeofthelifehis t o ry ofthechum salr on i s show n in figure 3 , and principal featur Figure 1. - - Mal e chum salmon at t1ll1~ ,)f spawning . of th ' life history are compar ed w ith those the other Pacific salmon in table 1. LIFE III STOll\'" The f,'ma l e takes a more active partthant: male in th e spawnin g process. When she Chum sal n10n are anadrornulls, i. e., they r eady t CJ spawn, s h e turns on her side and di rpturn to fresh wat e r to spawn aitl'!" spending a serit's of '>mall depressions o r pockets inti _nost uf their life in th e sea . [hey spawn in gravel by b eating h e r tail o n the str eam b o ttor gravelly riffles in a wide range of stream hab­ The aggregate CJ f these d e pr ess ions is call, itats - -from the tidal flats o f small strcams tu a nest o r r e dd. As ed.c h depression is dug, tI springs in the h eadwaters uf large river sys ­ fen1ale extrud s a few eggs, w hich are f e rti tenlS that are hundreds ufn1 iles fronl the occan. i zed b y m ilt extruded s imultaneously by tl The lungest known migration to a fresh - water male . The female immediately covers the fe) spawning area i s b y Yukon River churn salnlon, tilized eggs b y digging slightly upstream, wasl which swim over 1,500 m iles ups tream from ing more gravel into the pocket. After a ll eg~ Figure 2 . - -Mature male (uppe r ) and female (lower) churn sal mon. 2 EGGS IN STREAM GRAVEL 1/4 -INCH DIAMETER-SEPT.-DEC. It.... .~ ... ' ~~ ~~ .:. .... ~ 1It. '" 'I'.~f'¥. ..., l ~ ....,p j ap ~5' ~ ~"' I.,,;. <" .... i!':.~~.t. I \.~\ r: / , -­ :A.II"~_ : !" SAC FR Y, IN STREAM GRAVEL, I INCH L ONG - JAN. - APR . - . FEMALE ,.t'li';.~ ';:.. (>;; r. " ,..-_______________..... :~~~ ~~" SPAWNING FISH , IN STREAM , ~~ ABOUT 30 INCHES LONG, ~~3--T-0-5--Y-E-A-R-S-0-L-D----------~ ':» .~ ~-:;'W1j ~/ r ..~ i :·· · '· ~ ~-a:.~; ",~·~!f t-.... ~ ~ ~;~ FRY IN ESTUAR Y, 1-1/2 INCHES '~~~~ ~~~1,;; LO N G - MAY - J U N E ; .. ;. ..:, MATURING FISH, IN OCEAN , SECOND TO FOURTH YEARS Figure 3. --Life c y cle of chum salmon. 3 Tabl ' 1. --Genl'ral life hist r y features f th ' fiv ' IIpt' i'II)( cifi ,.lim ,n In AI sk ( xc lions t ( thes' g ·ne rd.] ell: cripti:>l1s ) cur fn·qu( ntly) Timl' sp 'l1l in [r 'sh 'r i m' y,.tr f SpeciL'ti Frl'tih- w<.lt'r o[ h<.lbit<.lt wa ter <.lfl 'r lif. a tialn1)11 l'I111' rg'l1 fJawnin. fr o l.l g rav ,I '\. l r Churn Sh \j't dlld Ll's" t h.1/) 2 - I 3- :; 3 . u 1 ln~ !"i t 1'".1 illS I 111 .nth Pink Sh lrt "trl'dll . u,tll I, s" 2 2.0 th,ln 1 dd Y C)ho '-ih lrt !"'tr\~l.1ll~ 12 - 2 I III .nth H J - I 3 - I 3 . 5 dlHI 1,\ l" S ,ckL'\'l' SI )1' tr".LI11~ 12 - ~! I nths I - I 3 - I 3 . 5 and 1..11 l'" Chin' )h, Lar~l' r i\ l 1'" 1- 12 'I 'Il h:; 1 - I 1- f 20 .0 ,\'ll~ht ,[ \\ h ']l II' l' llnd fls' . S. II' ,,: In. I' VI h . C nnm ., Bull . 12 , p . 1 (, ";Il,'d, thL' i"lll.L1, '::,I<.1l'd., 1, It,' 1r /I .Lnd • I r \ .1 d - b, l \ Ill' I' " 111 til h, (' I ... d I. \\ 1 r \ d • \ 1 •• ,'1' . h. h il'\\ "iUI'\ 1 l' tu L'nt, rthL' Ct' n .. 1 "it • 'j). 1 (lisdPPt' 11' d Irin", ti fJd\\ nln ,r eli" in /l., f r \\ . t.::1' 1\ L 1 cllrin.,: th, \\ inter. A i"ll.dl,· prl)d\ll , .... l' I 1, ()) t I, J ( l' (, g" 1 n h L' i,111, bu tilt' ~ n" 11\II11bL l' i fr~ tll it hatdl in thl "pring .ind 11 1 - ti),'Y .,:rate tc the "'.tn i" u";,I •.dly les,; than 10 per­ cent, fthl' n,lll bl'1' f e.,:_s "ducl'd.