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. E 'gti dnd ~ t'.tn, t1 t') t'el .,n 11 n drln fr\' p,'rish [1)1' n any l' u )n~: utiler ... pa\\nin~ d "\' h d bd rn.. Ie n sdln n(espL'ci,dlyldt('r "'Pd\\nin~pink "alrl1UIl) . " the) ro \. 1.1 r 11 d l II cidentall, di.,: up thL' ,.~t:,,; lll\\ stl"'.1I11 - 11 .; ind \\c rn \ "dth, ./1 a) reduLc the anlCJunt d. l X\ ~'n In ttl' '\dter t :ess thdn that r"quired b') (' d", Ina) \\'.1sh out deposited L'~g" vr ol('n. \\ i th thick layers uf gravel. excep­ tl)n 11\ low ten1peratures nlay freeze the eg~" • dlc,n~ tilL l.'dcc·" uf the "treanl during the winter; o r bird,; or uthe r fish may eat the fry as they mi.,:rdte duwnstream. EgC;s hatch during th e winter , and th e young salmon are nourished by the yol k of th e egg until they emerg e from the gravel in the spring . The time r e quired for an egg to hatch depends o n the temperature of the water; eggs hatch earlier in warm water. Laboratory experim e n ts have shownthat ata constant tempe rature o f 50 · F. , sal mon eggs h atch in a b out 50 days . Churn salmo n fry have a c haracteristic ap­ pea r ance -- g r eenish b ack, s ilve ry sides and Figure ,J" --Fry of churn salmon (upper) and pink b e lly , and a series of more o r less prominent salmon (lower) . The two species often occur narrow dark blotches o r parr marks o n the t ogether but are easily distinguished by the par r sides. In the sea the parr marks fade r apidl y marks on the churn salmon .

4 rther out into the o p e n ocean, they feed on fo re partic ularly d esira ble for caviar or fish lall fish, such as herring, o r o n larger in ­ bait. In 1968 the value of egg pro ducts from J: teb rates, especially e uphausiids . Altho ugh all specie s o f salmon in A laska was a b out $1 2 3 ture churn salmon stop feeding when they million; the value of canne d chum sal mon was ':ur n to the stream where they w ill spawn, the $ 28 million. M ost of the c hurn salmon for the . ~ rgy sto red in the o ils of the ir fl esh s ustains canning a nd egg industries are caught i n purse (!m thr ough migration and spawning . seines , although a f ew are taken in drift g ill n e ts. The commercia l fishing season varies ECONOMIC IMPORTANCE in diffe r e nt secti o n s of Alaska from year to year but gen e rally i s from July t o October . F i sherme n get l ess mon ey per poun d fo r churn Churn salmo n a r e more d ifficult t o catch in .lmon than any other salmo n; nonethel ess purs e seines than o ther salmon, a nd fishe rm e n lurn salmo n ar e important t o A laska ' s econo ­ often credit them w ith superio r intelligenc e . y b ecause o f the ir abundance a nd w ide distri­ When a school i s e n c ircle d w ith the seine the l tion. Table 2 s h ows the numb e r of fish, the fish tend t o sound o r d i ve unde r the l ead line e sh weight, the number o f cases o f cans, and b efore the n et can b e pursed. Also, b ecaus e .e val u e of c hurn salmo n caugh t in A laska in c hurn salmon a r e often cau ght at a n advanced ;1 59 - 68. The value r epr esents the whol esal e stage of maturity , th e e nlarged sharp teeth and r ice of canned sal mon at the tim e it is first hooked jaws of the mal es may catch inthe web­ ::l ld. In additio n to the canned sal mon industry, bing, and valuable fishing t ime is lost disentan ­ pres e r ved - egg industry i s devel oping rapidly. gling them. hurn salmon eggs are l a r ger and brighter col­ In additio n to the churn sal mon caught fo r can­ red than those of oth er salmo n and are ther e - ning, hundr eds of tho u sands are taken each y e ar

'a b l e 2 . --Number of fi sh , 1 weight, 2 numbers of standard c ases, 3 and whol esal e value of canned pr oduct4 for churn sal mon in A laska, 1959 - 68 (not includin g subsistence catche s)

Wholesale value ~ e ar Fish caught Pounds Cases of canned pro duct

Millions Millions T h o usands Millions

L9 59 32 415 $ 8.5 19 60 48 62 7 12. 9 19 6 1 6 46 5 15 12.5 1962 7 58 702 16.3 19 63 4 36 433 8 . 6 1964 7 63 69 1 12.2 1965 3 29 301 6 . 3 1966 6 52 585 14.6 1967 4 32 339 9. 1 1968 6 52 641 28.0 Average 6 45 525 $12 . 9

lWhole or r ound fi sh. Source: 196 1 data--A laska Dep. Fish Game , Statist . L e afl . 11, table 21; 1962- 67 data--A laska D ep. Fish Game , Statist. Leafl. 15, table 1 0; 1968 data-- on file Bur. Commer . Fish. Statist. Off., Juneau , A laska 9980 l.

lW"h ol e o r r ound fish . Source: 1959 - 67 data-- A las ka Dep. Fish G ame , Statis t. L e afl . 15, table 20; 1968 data-- on fil e Bur. C ommer . Fish. Statist. Off., Juneau, A laska 99801.

3A standard case contains 48 I-lb. cans. D ata from Nat. Fish. Yearbook Issue, 1968 , p . 110.

4Source : 1959 - 66 data--Pac. Fish., 64th Yearbook Number , 1967, p . 110; 1967 data--A laska Dep. Fish Game, Statist. L eafl. 11, table 18; 1968 data - - on file Bur. C omme r. Fish. Statist. Off., Juneau , A laska 9980 1. 5 for personal use by A l aska natives (Indians , mon , and th n d for larg quantities of A l euts, and Eskimos ) a l ong the large riv rs of for dog food is diminishing . the Bering and Chukc hi Seas north of Bristol Th State of A l aska D partment of Fish Bay. The importance o f this perso nal - use G ame regulates fishing for chum salmon to catch i s sometimes overlooked b ecause the fish sure that suffici nt numbers of spawners es are not normally sold and therefore are not re­ to spawn and maintain productio n. To ach corded in most tabulations of the catch . Set this goal the agency uses information from gill nets anchored in river eddi es ar the usual search done by its own department and by means of capturing these fish, but in the Yukon Bureau of Commercial Fisheries. The se and Kuskokwim Rivers n10st of them are caught tists work to sol ve such questions as: How with fish wheel s. chum salmon will return to Alaska waters The natives preserve c hun1 salnlon for later year? What abundance of spawners is ne use as human or dog food by drying it in the sun t o produce th greatest number o f fry migra and wind o n pole racks along the river banks (fig . to the sa? What factors in the fresh - water 5). The entire carcass , including the head, is early marine life limit survival of eggs and us ed, and thick portio ns are slashed to facili­ Why do the number s of adult chum salmon tate drying (fig . 6). The milt Lind the eggs are widely from year to year? Research is often dried a l so. viding some of the answers to these questi The recent rapid increase in the use of mo ­ but so far only a beginning has b een made. torized toboggans for transportatio n by Arctic is known about the biology of chum salmon Alaska natives has made dog teams less com - of any of the other Pacific salmon.

Figure 5. --Chum salmon drying on the bank of a river.

6 1954. Age and growth study of Tillamook B ay chum sal mon (Oncorhync hus k e tal. Fis h . C omm. Oreg., C o ntrib. 19 , 28 pp. HUNTER, J. G. 1959 . Survival a nd production o f pink a nd c hum sal mon in a coastal stream. J. F i sh. R es . Bd. C a n. 16: 835 - 886. MA TTSON, CHESTER R. 1962.. Chum sal mon r esources o f Alaska from Bristo l Bay to P o int H ope . U. S . Fish Wil dl. Serv., Spec . Sci. R e p . Fis h. 425, i v + 22 pp. M c NEIL, W I LLIAM J. 1966. Effec t o f the spawning b ed e n v iro nm e nt o n r epr o ductio n of pink and chum sal mon. U . S . Fis h Wildl. Serv., Fish. Bull. 65: 495 - 523 . NEA VE, FERRIS . 1953. Princ i pl es affecting th e size of pink and c hum sal mon populations in British C o lumbia. J . Fish. Res . Bd. Can. 9: 450 - 49 1. 1958 . The ori g in and speciation of Onco ­ rhynchus. Trans . RoyalSoc . Can. 52: 25 - 39 . 1966. Chum sal mon in B ritish Columbia. Int. N . P a c . F ish. C omm., Bull. 18: 8 1- 85. SHEPARD, M . P., A . C . HARTT, and T. ·gll re 6. - -Chum salmon which have been s lashed YONEMORI. t o facilitat e drying . 1968 . Salmon of the No rth Pacific Ocean, part 8 , Chum salmon in offsh ore water s . SELECTED REFERENCES Int. N . Pac. Fis h. Comm., Bull. 25, 69 pp. THORSTEINSON, FREDRIK V., WALLACE H. IAIG- BROWN, RODERICK L . 1956. Canada ' s Pac i fic sal mon. D ep. Fis h . NOERENBERG, a n d HOWARD D. SMITH. Can., Ottawa . 29 pp . 1963. T h e l e n gth, age, a nd sex ratio of c hum . ENR Y, K E NNETH A . sal mon in the A laska P enin sul a , Kodiak 1953. Anal ysis offactors affecting the pro ­ Is l and, and Prince William Sound areas of ducti o n of c hum sal mon (Oncorhynchus A l aska . U. S . F i s h Wildl. Serv. , Spec. ketal in Tillamook B ay. Fish. C omm. Sci. R ep. Fish. 430, i v + 84 pp. Oreg., C ontrib. 18 , 37 pp. MS. # 1935

7