Northwest Science Forum

North*est Science Fonnt protidas ttt oppofiunitl to drticultie and discLrs.s scientiJic is.sues ina less stnrttured lbrnul lltcut peer-rcviev,ed artitles. The Forwn pubLishes short drticles, opinion pietes, utd letters with a.fottts ort stient'e und nalurdl resource isstres i the Pu(ific Norlh-west. ALthough the Fotant is |ot paer-reriewed, it is edited for format antl clarity". Articlesshoulcl genenll-t be less thLtn 2000 words and untail ninimql lileruture citations. Letters inresponse to atrticles are purtictrlorly ent'ouraged: tlr origindl eutltur vill normall,'- be given aclLante b resporul to the letter as \rell. Tltere ure no page t'harges or reprints (tssot:ittted witltthe Forun, ond partitipunts neetl nctl be nembers ofthe Northwert Scienlilic Assttciation. Pleasesertd all strbmissions, ittcluding two hard tr4tias untl tut electronic co1t,r- (anl re(e l rersion ol'Wtrd or WordPe4ect) to the Editor

Thomas P Quinn, F sheries Researc h lnst tute Schoo ofFshefes Box 355020 Un versity of Wash ngton SeatteWashington 98195

Revisiting the Stock Concept in Pacific Salmon: Insights from Alaskaand New Zealand

Introduction and Historical Perspective

Although s)'stematists classify organisnN by phy-lu rn . c l r . . . o tdcr . l r t t r i l l . !enu . rnd .pec ie . . i t i -widcly appreciated that these are poinls along acontinuum oI genetic relatedness and evolution-J r \ \e lJ r ' : r l ron r M15 r 1982 t . Th i . . r ' n t inuum c t .tends to rcproductively isolated breeding unitswithin spccics. known to geneticists as denrcs andto nost t ' ield biologists as populations. Thesepopulations tnay be spatially isolated from eacbothcr ifthey are on sepante islands. mountaintopsor in ponds. Hower,er. in nany animals thc isola-tion of populations is not a simple mattcr of geography and limited mobil ity but rathcr one ofbehavior. Many populations have broad, ovcrlap-ping leeding distributions but segregate at thebreeding season. each returning to the site \\"herethcy were bom. Anorg the nlost t'innous exan-Iplesof this phenomenon are the anadromous fishessuch as Anlcrican shac! (Alosu .sdpitlisslrm) andsalmon (Orrt orfrynclias, &r/no and Snhellrrus spp.)(Quinn and Diftman 1992). Thesc fishes arespawnecl in frcshwater. migrate to sea to teed andg lou . un , . l Iher r re lu rn I i , rpJun. a lmor l in r i r r i -rbly in the sarne stream or lakc where they werespawned.

312 Nor lhues t Sc iencc . Vo l .73 , No. ,1 , 1999

a l 9 ! 9 h t t h . N r i h \ . n S : t r r r i t L i ̂ ! \ o . r d m A l l r i l h r ' e \ e r \ c d

Some astute scientists inlered the homingphenomenon in the 1800s tionr phenotypic dif-ferences in tlsh tiom diff'erent rivers. Milner (1876)noted '[t]he gencrally accepted fact in the habitsof anadronous fishes that they are disposcd toIetum to almost the exact locality where they passedthcir enbryonic and earlier stages of growth...Observations of the shad brought to the largemarkets shows considerable dit ' tbrencc in thcphysiognorny and general contour of those fromditf'erent rivers. The suggestion is natural that the,yarc distinct aDd separate colonies of the samc\pec ie \ . rnd thu . . l igh t .h . r r r ( le r i \ l i . : J Ic perpctuated because they breed in-and-in and do notmix $'ith those ofothcr rivers." Others concludedl ' r , \m Ihc i .u la red locx1 i6n . s l . .1 lm, rn .p . ru n inggroups that these must be fish rcturning to theIocation where thcy had been spawned. A repofifrom thc United States Commission on Fish rndFisheries (1876) stated, "This stream IDearElko,Nevadal is one of the nany that tbrm the head-waten of the Columbia River. and to this point,cighteen hundred miles fiom its mouth. the salt-water salmon come in myriads to spawn... Fromthese lacts we may infcr that the instinct of loca-tion is probably sullicielt to attract a colony offishes as lar inland as the head$'atcrs of the longest

dver, whenever theil home has been once estab-lished there."

Although honing is a fascinating phenomenon in its own right. the separation ofthe salmonspecies into more-or-lcss discrete populations isthe key element in their nanagemcnt and con-servation. The brsis of this so called stock con-cept is that salnron inhrbiting different rivers ex,perience different pattems of natural sclcction,owing to differences among rivers in abiotic factors such ls llow regime, tempelature and sub-strate, and biotic factors such as predators, competitors, prey and pathogens. These diflcrencesin selection result in salmon that differ in color,fat content, size, agc. t iming of migration, disease resjstance, and nany other phcnotypic traits.Rivers may diffcr in the productivity oftheil salmonpopulations or their canving capacity (Moblandet al. 1997). thus thc populations must be managed as separate entities to prevcnt over-fishinglcss productive populations when they intenninglcwith more productivc ones. The coonection between salnon homing. population-specific traitsand conservation wrs the focus of a landmarksymposium held in 1938 in Ottawa. Ontario.Canada (Moulton 1939). Several papers presentedevidence tbr the population specific traits of At-lanLic and Pacific salmon (e.g.. Rich 1939) andthe published discussions mtke it absolutelv clearthat these scielt ists saw the close conncction be-twccn homing. the stock concept. and salnonconservation.

Thc next major advance in the field ofsalmonpopulation biology camc with the publicatior ofanother symposium. also held in Canada, as partof the H. R. MacMillan Lectures in Fisherics atthe University of Brit ish Columbia in Vancouverentit led "The Stock Concept in Pacific Salrnon"(Simon and Larkin 1972). There were severalinteresting papers. but the volume is doninatcdb 1 R i c k e r ' . d ( t r i l c J r ( \ i c \ , ' l i n t i , r l r a t i o n o nsalmon homing, the differences anrong popula-tions in various phenotypic traits. and the gcn-eral failurc of transplanted salmon to thdve asrvell as local populations (Rickcr 1972.). Thisoutstanding review of the early l i terature is sti l lwidel)' cited today and was the key publicationin the field unti l 1981. rvhen a special issue ofthe Canadian Journal of Fisherics and Aquitt icSciences published papers from the Stock Con-cept lntenlational Synrposium. held in 1980 in\ l l i . ton . Onrar io . Thc i \ .u r h i rJ p rpr . r . , , l . r \ r r i -

ety ol fishcs, including sea lamprey (Petl.d7r_r;otnrurinus), largemouth bass ( Mitrt4ttenruthnoi d e s). and walleye (.Sti:o st edi on v i tre u n),but many were on salmonids. including very usefulreviervs on Canadian populations ofAtlantic andPacific salmon by Saunders ( 19131) and McDonaldr l q 8 l , - r e . p e c r i \ e l ) . A \ $ i l h t l r c f r e \ i u u \ \ ) t nposia. thc authors clearly drew the l inks betweenhoming, stock specific variation in phenotypictraits, and thc conservation and management ofpopulations. In the years that fbllowed this sy1nposiurn. many papcrs were published. documcntingvariation among salmon populations in a rvidevaricty of adaptive traits. Taylor ( 1991) reviewedmuch ofthe litcrature and pointed out that in somecases of 'local adaptation," only phenotypic varia-tioD was documented. He argued that local adap-t r t i , ' n imp l ie r no t on l ) phent \ t )p i ( \ r r i . r l i oo"n tL) r ) .populations in a given trait but also a genctic ba-sis firr the trait, and a dcnronstrated survival ad-vantagc associated with the trait.

In addition to the large and growing l iteratureon population-specilic variation in adaptive traitsamong *' i ld salmon populations. the lrst tew decades have seen rapid expansion of salmonidaquaculture. The successful cuhurc of sal monidsdepended in part on the choice of suitablebroodstock. and subsequent selective breeding forchosen traits. This requirenent lcd to many experlments on thc gcnetic control of traits of inr-portance in culture such as fccundity and gro$,tl'l(e.g., Gjedrem 1983, Hershberger et al. 1990.Crandall and Gall 1993, Su et al. 1997. J6nassonet al. 1997). The gcncral conclusion ofthese cx-periments is that there is a substantial geneticcorllponcnt to most ofthe traits. though ofcoursethere is a degrcc ofenvironmental control as well.Finally, the 1970s and 1980s sav the de\,elop-ment and usc of molecular techniques to stud)'thc population genetics of f ishcs and especiallysalmon. These tcchniques init ially used naturalvariation in the propofiions of more or less se-lectivcly neutral polymoryhic protcins to denlonstrate reproductive isolation of salmon popu-lations (see review by Ulter 1991). More rccently.vadation in mitochondrial and nuclear DNA hasalso been used to study the population sffuctureof saln.ron and othcr fishes (e.g., papers in thespec ial issue ofReli eu,s of Fish Biology and l islt -erie.i. cditecl b1' Carvalho and Pitchcr 199.1).

Thus thele have been three major l ines of research into thc subject of the "stock concept" or

N0rth$ e\t Science Forum 31-l

evolution of salmon populations: natural variation in phenotypic traits, controlled or selectivebreeding. and variation in more selectively neu-tral molecular traits. As was pointcd out in thel0Q4 Amcr ic ln Fr rher ie : Soc ie r5 s1 mpos ium on"Evolution and the Aquatic Ecosystem" (Nielsen1995, and notably Hard 1995). all are valid approaches and nccd to be integrated into a holisticvicw of salmon population structure, evolutionand management (see also Utter et al. 1993. Grantet al. 1999). These lines of rcsearch. undertakenby scientists with diverse backgrounds and intercsts. form much of the scientific fi'amework tbrthe application ol the U.S. Endangered SpeciesAct to salmon populations (see discussions ofthisissue by Uttel l98l: Waples 1991, 1995).

Taken as a whole. one can look at salmon popu-lations fiom two perspectives. First. they havecountless, genetically-bascd specializations forunique biotic and abiotic features of their environments. This perspectivc, bolsteredby the generaltailure ol anadronrous salmonid transplants(Withlcr 1982. Fedorenko and Shepherd 1986.Harache 1992), sees salmon populations as tightlyevolved fbr their natal systems. reinfirrccd by neulyunerring horning behavior. The intermingling ofp , 'pu l r t ionr mc) p re \en l mrn lS :ernent agenc ie .tiom protccting the fine genetic stucturc but suchstructurc cxists. An altemative and perhaps comple-mentary perspective (e.g., Quinn 1985, Wood 1995)is that since the post-glacial period, dispersal hasbeen as much the hallmark of salmon populationbiology in the long run as homing. Followingcolonizalion of new habitat, subsequelt homingisolates the nascent population. Natural selectionand the high heritability ofadaptive traits can leadto their rapid evolution. Differences in selectivelyneutral differences (e.9., nolecular) traits may arisetr-om fbunder efl'ects at the timc of colonization,or from clrift over long periods of time.

Having presentcd this brief, and obviouslyselective. introduction to thc subjecl of the stockconcept in salmon, thc purposc of this paper is to

nre \en l \ ludrc : \uppof l rnB lhe \e l \ operspcc l i \ ( \, ' n Ihc (oncep l : f ine tuned ad lp ta t ion or g re l tcapacity for evolutionary adaptation. The stud-ies are drawn in luge part frorn my own work.not bccausc it is definit ive but because it is farnr l i r r lo Inc . l t i s n , ' t 1ny ub jcc l i \e lo con\ incercadcrs that either pe$pective is conect. but rathert , \ emphc. , / c the va l id i t l o l bo th \ ieupo in ts .

31 '+ Nor th$es t Sc ience. Vr l .73 . No. ,1 . 1999

What Constitutes a Populatlon?Perspectives from Brlsto Bay, AlaskaSockeye Sa mon

The North American range of sockeye salmon(.Onc:orhynchus nerknl is primarily from the Columbia River to the Kuskokwim River in the BeringSea (Burgner l99l). Early research by the Inter-national North Pacific Fisheries Commrssron re-vealed that Asian sockeye srlmon (chietly fronrthc Kamchatka Peninsula and Russian coast ofthe Bering Sea) dif lered in rnarine distributionfrom North American conspecifics (French et al.1976) and for some management puryoses thecontinent of origin was the relevant scale tbr the"stock" (Figure 1, top; Harris 1987). However,data from tagging studies and analysis of natu-rally occurring parasites revealed that the distdbution of sockeye salmon tiom the Bristol Ba)'rcgion of southwest Alaska differed from thoseof other populations to the east and south (Frenchet al. I 976). For example, the Fraser River com-plex of sockeye populations shows a differentmarine distribution (Figure l, bottom), and alsodiffers from Bristol Bay sockeye in sur\'lval ratepatterns (Peterman et al. l99ti).

Bristol Bay has somc of the world's lafgcstpopulations of sockeye salmon (Burgner l99l).These populations suppot imponant lisheries andhave been the focus ofmuch research, and in somecontexts ''Bristol Bay sockeye" is a meaningfulstock or stock-complex. Despite the many lakesystems tributary to Bristol Bay where adult sockeye salmon spawn, the adults gcncrally rctunr overa rarrow time period (Burgner 1980). The popu-lations also display cohercnt patterns of size atage and age at maturity (Rogers and Ruggerone1993, Pyper et al. 1999), suggesting comrron re-sponses to ocean temperature and density-relatedprocesses. Although for some purposes it is appropriate to speak of Bristol Bay sockeye, themanagement is based in disfficts at the mouthsof the major dver systems: Ugashik, Egegik,Naknek-Kvichak, Nushagak and Togiak, and tosome extent these distdcts are functional stockunits (Figure 2). As Minard and Meacham ( 1987)pointed out, this district based management canlead to diff iculties. For example, f ishing in theNaknek Kvichak disbict catches sockeye migratingto the mydad streams in the Naknek and Iliamnalake systems, and fishing in the Nushagak dis-trict intercepts fish with very different pattems

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Northwest Science Forum 31-5

districts ) \Wood

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Figur!'2. Map of Bristol Bay. Ahska. sho$ing the lisling disrricls and localiolrs of couniing to\rers rbf $cke)e salnn)n (nmdi-

r'ied rionl Nfmard md Mcacham 1987).

ofproductivity and lite history. going to discretespawning sitcs in the Wood River. Nushagak,Nuyakuk and lgushik systems. There is alwaysthe danger of over-fishing one population whileattempting to fully fish another. Eflbrts to avoidsuch management problcms are complicated bythe similar t imirg ofthe populations and the geo-graphical proxinrity of thcir mouths. Counts ofadult salnron rnigrating past torvers such as theone at Igiugig on the Kvichak River provide in-season feedback tirr managcnrcnt (Minard andMeacham 1987) but sti l l ercompasses mirnyspau ning populations.

Evcn thc l'ish migrating to a given liyer s)s-tem may have very similar t iming, as Smith ( 196.1)and Jensen and Mathiscn (1987) denonstratedfi)rthc Kvichal system. Sockeye tagged throughoutthe lun were rccoveled at diverse sparvn in-{ grounds

316 Nor thwest Sc ience, V01.73 , No.4 . 1999

in tributaries and beaches of lliamna Lake andLake Clark. Thus from thc viewpoiDt ofcomnercial fishcrics nanagement, the Kvichak River isthe smallest practical unit. even though it encom-passes about 100 documented spawning sites (Figure 3) and tu'o of the largest )akes in AlaskarDcnror ) e l r l . lq6+r . Th( Wood R i rc r r )s temincludes about 50 spawning populatrons assocr-rted rvith a complcx chain ollakes (Mariott 1961).Like the Kvichak River system. it is also managed as one unit theugh estimates are made ofthe abundancc of adult sockeye salmon at mostof the spawning sites.

The sockeyc salmon ascending the Wood Rivertend to spawn in three major types of habitats:small streams,large rivers (flowing between lakes)and beaches. Rogcrs ( 1987) pointed out the greatvariation in age structure among these groups.

F i g u r c 3 . l V a p o l l l i u m n a I - a k c . A l a s k a . s h o $ i n g \ o m c o l t h c i s l a n d s i n t h c $ L ' \ l c m p a n o l t h c l a l c a n d l l c r i \ c n r h a r a r c u s c d i b rspa$ning by sockete salmon.

Notably. river spawners tend to spend three yearsat sea and so are largel thalt the creek spawners,which tend to return afier two vears rt sea. Thepopulations also differ in morphology. especiallythe development ofthe dorsal hump in males. Creekspawners are much less deep-bodied than riverfish ancl the beach spawners are very deep-bod-ied (Bishop 1990, Wetzel 1993). The river andbeach spawners in Il iarnna Lake show parallelpatterns of morphology (Blair cL al. 1993) andthese have been hypothesized (Blaif et al. l993,Quinn and Foote 1994) k) result t iom the con-flicting pressures ofsexual selection (filvoring deepbodies) and bearpredation (Hanson 1992. Quinnand Kinnisol, in press).

In Iliamna Lake. there are sockeye salmonsparvning on beaches oflor-lying islands. u'herethe embryos incubate in watercirculated by winddriven surtace currents. Only a t'erl knr a*ay otherfenales spawn on mainland beaches and spring-l 'etl punrl: .upplir 'rJ u ith upu r:l l ing u atcr Thc eggrdeposited by lemales on the island beaches areexceptionally Iarge whereas mainland beach andpond ttmalcs havc vcrl ' small eggs, and thesepattems of egg size natch the size of the sub-

strate in which the embryos incubate (Quinn elal. 1995). There have been no tagging studies toexplicit ly demonstrate homing by sockeye salmonlo d i sc re le .pau n inF . i te . bu t na tura l r a r ia t ion inotoliths strongly indicates that sockeye return totheir natal incubation sites (Quinn et al. in press).This finding is consistent with molecular gencticvadation among spawning sites within this andother lake systems (Varnavskaya et al. 199.+).

For some purposes we might think ofthe sock-eye salmon spawning on the beaches of [ l iamnaLake as a population because they clearly sharemany attdbutes such as egg size, fecundity. ageand lcngth at maturity (Blair et al. 1993). How-ever. is there finer stlrcture to the populations?Experimental displacement of mature salmon(B la i r and Qu inn 1991) and surveys o f spawningdates (Quinn et al. 1996a) provide circumstantialevidence that the fish using each island representseparate populatioDs. Not only is there apparcntlyfine populaLion structure on spatial scalcs butthcrcis evidence tbr tenporal isolation as well. Evelwithin a singJe beach on one island, a certaln sectroDis always occupied prior to nearby areas (Hcndryet al. 1995). The high heritability of maturation

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date (Snoker el al. 1998) means that there ma)'be patterns of genetic structure over the courseoI thc spavning season within a single site(McGregor et al. l99U). The fish that anive carlyin the season not only sccm te l ive longer i it thestream than late ariving fish but also display dif-ferent pattems of energy rllocation (Heldry etaJ . 1999) .

These studies of Bristol Bay sockeye salmonrurcu l r .e r ic i o [ .ca lcs a t uh ich ue mul r ieupopulations: Nofth America. Bristol Bay. Naknek-Kvichak or Nushagak fishing districts, KvichakR i r e r o r W o o d R i r c r t o u e r c o u n l \ . . p l $ n i n ghabitat types (bcaches, creeks and rivers). indi-vidual islands or crccks, and even temporal seg-ments of the run at a givcn site. Sonre scales suchas contlnent or_reglon ate too coarse to be meaningful as populations and othels such as creeksor segments of the run to I creek are much toofine to be manageablc. Nevertheless, studieson the tlnest scale arc useful because they re-verl the extraordinary suite of adaptations thatnatural populations can display as evolved andphenot l p rc r l l l n l r . t i c re \pon\c \ to cn r i r , ' nmen-tal variation.

How Rapidly Can Popu ations Evolve?Perspectives from Ch nook Sa mon in NewZedand

Thc almost endless ways in which natural populations difler f iom each other. and the complexadaptations to the environmenI that these di11-erences sccm to demonstrate. raise thc question ofhou'rapidlv these differenccs can evolve. Muchof the present range of Pacific salmon was lastglaciated about 1G15.000 years ago. and straysfounded thc present populations. Thus not onlyhon]i[g but a]so str-aying is an ill.rportant compo-nent of the l if 'c histery and evolution of srlmon(Quinn 1985). The ditlerences in genc fiequen-cies that are observed among populations haveprcsumably accurnulated gradually through ge-netic drilt but selective breeding studies revcalhigh heritabilitics ft)r important life hislory traitsand imply that populations might evolvc quitequickly, given sufl iciently intense natural selec-tion.

Transplanted populations provide opportunities lor studying the early stages of adaptation k)neu envifonments. There are couDtless iDtroducedlieshwater populations of salmon. trout and char

318 Nor thwest Sc ience. Vo l .73 , No. ,1 , l999

worldu'ide but anadromous salmonids havc pnrvenvery diff icult to successfully lransplant. This re-striction is surprising bccause most population-specific difltrcnces seem to be adaptations foraspccts of the freshwaler environment (Tavlorl991.1 and one would think that marine I it'e wouldbe more generalizcd and so less problernatical innew environments. Ncveftheless. the transplantof chinook salmon tiorn the Sacramento River(probably Battle Creek, Quinn et al. 1996b) tothe Hakataramer River on the South lsland ofNewZealand (NZ) in the early 1900s was successfuland the fish quickly colonized much of the suitable habitat and established sell sustaining popu-lations in such large rivers as the Waimakariri,Rangitata and Rakaia (Figure 4), as well as smallerrivers.

Colonization must have becn prevalent in theearly years. given the rapidity with which thesalmon distributed themselves. but presenldayestimates indicate that the homing ol NZ salmonis comparable to North Anerican populations(Unwin and Quinn 1993). Examination of datacollected over a period of years in several of themajor chinook salmon rivers revealed diflerencesin several ofthe life history traits conrmonly usedto charactcrize chinook salnon populations inNonhAmerica: frcshwater lile history type (yearling or subyearling migrants to sea). age at matu-flty, length at age. weight at length, fecundiry.and the timing ofretum fiom the ocean and spawning (Quinn and Bloomberg 1992, Quinn andUnwin1993). These differenccs indicated that thc popu-lations are now phenotvpically ditferent, thoughthe extent to which these diflerences reflected onlydiffercnt rearing conditions could not be dcter-mrDed.

To determine *hether chinook salmon havcevolvcd into genetically distinct populations (insome sense of thc word) during about 30 generations since the transplant (at a mean age of about3), rve initiated a large-scale controlled breedingand rearing experimcnt in 199,+. The null hypothesis was that the fish from diff'erent rivers wouldnot differ when reared under common conditions,implying that the differences in phenotypic trairs, 'hservcd in thc ca r l ie r s rud ie . werc cn r i ronnrcntally induced. On the other hand, consistent dif'-Ie rencc . be lueen p , . rpu la t ion . rn t l genet ic con-trol (i.e.. heritabil ity) within popularions wouldlnply that the populations had already reachedsome level of gcnetic dil lerentiation.

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In 199.1 and 1995. we sampled adult salmonfron two populations that had shown phenotypicdifferences. thc Hakataramea River and Glenarift eStream. and recorded data on length, weight, age.morphology, egg size and t'ecundity. These phenotypic data were compared to data on fish liomthe cunent representatives ofthe ancestral BattlcCreek. California population. We then spawnedthe NZ fish in a half:sibling mating design to al-low us to eslimate the geDetic contribution to lit'ehistory traits, and began a complex incubationand rearing experiment. Wc rcared some families to nlaturity under common, controlled con-ditions in freshwater. In addition, wc released

representatives from the families from two dif-t'erent hatchcrics (Glenariffe and Silverstream).The use of two hrtcheries provided somc mca-surc ofinsurance against poor year class sur-vivalat one site and also allowed us to compare thepcrtbmance of fish retuming to one hatchery l]earthe coast (Silverstream) and onc larthcr inlandand at higher elevation (Glenarit le). In 1997, rveinitiated anothercontrolled breeding experiment.this timc with fish fron Glenariffe Stream andthe Poulter River. the lirtter chosen because theadults diff'cr from Glenarifle Stream fish in spawning date and juvenile l i fe history.

Northwest Science Forum 319

Our lesults shorv a ntosaic of traits. somc ofu i r i ch r rc i rppr ren l l ) unL le r : l r . ' n1 : e l ) \ i ronmen-lal control and othcrs have a clear gcnetic basisand dif ltr bet*een populalions. The adult chinooksaln.ron ditler in morphology fionr Battle Creek,Calit irrnia fish. and also clift 'cr (though to a lesscrextcnt) bet\\"een the two New Zealand populations (Kinnison ct al. l99Ea). \! 'e arc presentlyexamining the data on the otfspring l iom the cx-perimeotal NZ parents and so arc nol sure yethow nruch of the variation has a genetic basis.We have e!idcnce that the tempcrature specit'icr-ate of cmbq/onic development does not clifltrbel\\,een populatiurs, dcspite difterences bclweenthe ri\,ers in thcmd rcgime (Kinnison et al. 1998b).Salmon populations adapt the timing ofjuvenilecnergence primarily by diflerences in parentalspawning date, which is strongly heritablc (ourunpublished data) lather than dcvelopmental rate.

Growth ratcs differed slightly bet*een Haka-taranrca lliver and GlenrrillL Stream tish (Kinnisonct 11. l99Ec) but thc Poulter River fish grerv muchslower than Glenarill-e Stream fish under com-mon conditions (our unpublished datt). This diflerence is particularly intercsti ltg because thcPoulter River fish Lend to spend a full year i lt leshu'ater prior to seauard migration whereasGlenarific Stream llsh rear in warmer water andt)'pically migrate to sea in thcir f irst year of l i fe(Unwin and Glova 1997). wc infer that the fun-drmcntal environmental basis for grorvth di1'fer-cnces betrveen populations is becoming reinforcedb1 r genclic difttrence as wcll. Smaller f lsh rreless tolcrant of seawater than larger lish (Kinnisonet al. 1998c) and also have lo$er survival ralesat sea (unpublished data) so there wil l be conlin-ueJ .c lc r t ion lh r l i .h in . l t ' u g to \ \ lhen \ i f , ' r rmun l .to rcnain lbr r full ycar before going to sea thelife historl pattcrn refened to as stream type (seeTeel et al. 1999 for insights into the evolutionar)'basis of stream-type and ocean t,vpe l ite historics in Nolth America).

Survival al sea was rot onl," ' correlated withsnolt size but thcre were also family-level dif:ferences independcIrt of size, suggcsting sonegenetic basis tirr survilal. Survival is nol a tmitin itself but a consequence of many traits includ-ing growth, seawrter tolerance, prcdator avoid-ance. etc. Perhaps mosl exciting $'as our finding thal the two populations (Glenarit le andHakataramca) showed sinrilllr sur!ival rates when

320 Northwcsl Scierce. Vol.73. No..1. 1999

released from a site which was home to neitherpopulation (Silverstream) but that Glenariffe fishhad a significantly higher suryival rate thanHakataramea River fish when released fromGlcnariffe Stream. This "home site advantage"implies that some form of adaptation for the na-tal site has taken place that all-ects survival. Ofthc fish that swvived and returned to the hatcher-ies, there is littlc evidence ofinter-population dif-fcrences in size at age, but we have detected con-sistent differeDces between populations in thetiming of return and maturation, and also in fe-male reproductive traits such as egg size. Theenergctic demands ofuprivcr migration also seemto affect egg size. so the phenotypic traits seen inwild tlsh ret'lcct the interplay betwecn genetic andenvironmeDtal controls. The genetic ditlerencesbetween populations inphenotypic (possibly adap-tive) tmits contrasts with the low level of varia-tion among populations fbund using molecularmarkers rvithin NZ, though the NZ tish difleredirom the Sacrrnrcnto River l lsh (Quinn ct al.1996b). Furrher srudies, using DNA microsatellites,are ongoing but it seems that selection hils workedquickly on lilt history traits and ddft nray lead todifferences, albeit snall. in more neutral traits.

One additional f inding, though not cxplicit lya gotl of the study, was that many male chinooksalmon held in lieshwatcr becane sexually ma-ture at one year ofage. This is not unprcccdented,either in New Zealand or in thc native range, butwhat was surprising was that they survived spawning and lived to spa*'n again, not onl)' at age twobut in sqnc cases a third time at agc three (Unwinet al. 1999). This i l lustrates that some aspects ofsalmon lite histories, which we view as flxed, suchas senelparity (i.e.. death afier reproduction). mayactually be flexible but reveal only one patternunder normal cnvironmental conditions. Anothercxample ofthis phenomcnon ofapparentJy tixedtraits thrt change in new environments is the ageat matudty of pink salmon. Alnost without ex-ception they are two yeaIS old at maturity in theirnatural rangc but they have been reportcd to mature fuom ages l-.1 in thc Great Lakes (Kwainr 987).

Conclusions

The population biologl'. genetics and conserva-tion of l ishcs and salmon in particular is anexceptionally vital area of lesearch. as revealcd

by thc diversity of papers in the American Fish-eries Society symposium edited by Nielsen (1995),the set of papers in a spccial section of the iour-nal Consen ation Biology (Hed-eecock et al. 199.1).and thc contributions ofmany scientists to a widevariet.v of other publications. Ihavc triedtopfesenttwo perspectivcs on the subject.InNofib Arnerica.we see stocks or populations delincd over a rangeofscales, dcpcnding on the management goal andthe tools of the scientists. We can observe differences in phenotype and often also genotype rtspatial scales that may be too small firr all bc themost draconian tisheries managcment to activelyprotect. These myriad specializations are clearlycrit ical to the hcalth of salmon populations. Inmany cases there are obvious adaptive advantagesto the traits, and t'ailurc of the vast maiority ofsalmon inffoductions $'ithin and outsidc the naturallange of the species dso testifies to the impor-tance of local adaptations.

How. then do we intcrprct &e evideDce liomNew Zealand that sdmon can apparently evelvequite quickly? Does this mean that all wc need toconserve are a t'ew gcncdc salnoD stocks and u'ecan use them to replenish any habittt from whichsalmon are lostl Or does thcir rapid evolutiondemonrlrl l te hrr$ erit iell the Iocal adaptrtion\ ! lreto the l itness of individual salmor and the pro-ductivity ofpopulations? The scientists and policymaken $'restl ing with the application ofthe U.S.Endangercd Species Act to "distinct populationsegments" have a very difTicultjob. rveighing thevi:dous attributcs that define populations (Uttef1981, Waples 1991, 1995) . They must re ly onditfcrcnt kinds of data. including molecular markers. l i fe history traits, and gcology (e.g., Myerset al. l99E) k) definc the "evolutiorari ly signiti-

Literature Cited

ts idlop. S. NI. I 990. Nlorphonclric difierences rnnng spa$ n

ing populations of socke,ve srlnlon (On.orh\n(h s

,.,ftrl) in lhe Wood River L&e s)neln. \{rncr's llcris. tlni!er\ir) of \\'rshinston.

BlrLn. G. R. and t P Quinn. 1991. Honing and sp.r i 'n i rg

silc sclection b! sockeye sdmon (Or..),rrr.r&! nfr{24in l l iamnr Lake. Alaskr. Canadirn Journal of Zool-

o g y 6 9 : 1 7 6 - 1 8 1 .

cant units" that society viJl try and protcct. andmust deal with criticisms ofthe ESU concept (e.g.,Pennock and Dimmick 1998). My ou'n vrew rslha l lhere r re . , '16 , r p , 'pu l i r t ion . w i th un ique r ttdbutes and we should strive to protcct them butlbr the most pan we need to give salmon accessto healthy, diverse physical habitats and al1ow thoschabitats ro be filled (or over-tllled) with the llllcommunity of salmonid species nativc to thc re-gion. The salmon can take it lrom there.

Acknowledgements

Thc rcsearch conducted on Bristol Bay sockeyesalnon that I have dcscribed has been largelysupported by the Pacific Seatbod Processors As-sociation. I am very grateful to Don Rogers ofthe Fisheries Rescarch lnsti lute. School of Fish-eries, University of Washinglon, lbr his insightsinto thc salmon of that region. and the opportu-nity to participate in the rcscarch progran there,and I thank the nany graduate and undergradu-ate studelts who helped with thc work. The research on chinook salmon in Nerl Zealand hasbeen a collaborative effofi \\"ith Marlin Unwinand Nelson Boustcad of |he National Institute ofWater and Atmospheric Research. and MichaelKinnison and Will iam Hershberger of the Schoolof Fishe es. I thant the many staff associated withfish husbandry at Glenaritfe and Silverstleam, andwith sample processing throughout this sludy.Funding was provided by the Ne* Zealand Foun-dation firr Rcsearch. Science and Technology(Contract COl50l in Ncw Zealand.), and b.v aconsortium of Pacific Northwest power uti l i t iesand the H. Mrson Keeler Endowment (in the U.S.).Martin Unwin, W Stewart Graot and Fred Utterpror ided he lp lu l L . t ln Incn l \ t ,n lhe mr t )us( r ip l .

Blxi f , G. R. . D. E. Rogers and T. P Qui , ' . 1993. var ia l ion in

l i fe h istor ] chmlclc ist ic \ and nrorpholog, \ 'of sock-

eye salnlon in lhc K!ichak River s!stem. Brislol Br],

Al.rsla. Tra.sactions ofthe Ameficar Fisheries Soci

cry l l l :550-559.tsurgnef, R L. 1980. Some 1calurc\ o l occan migrat ions and

r iming oi Pic i i ic salmon. ln: Sal l lnrn id ecos!stensof ihe Nofih Pacific. \l'. J. NIcNeil rnd D. C. Hnns$ol1h(eds.) . Ofegon Srate Uni \er \ i t ) Prcss. Cor\a l l is . Oregon. USA. pp 153 16.1.

Nofih\\"est Science Forum 321

BurSner. R. L. I99 L Socke\e \a lmon. ln: P.rc i f ic salmon l i fehisrof ies. C. Groot rnd L. N{argol is (cds.) . Uni !ers i r !o I B ri ti sh Colu mbi.r Pfes s. Vancou! cr. British Coluln-bia. Canada. pp. I l l7 .

Can r lho. G. I t . and T. J. Pi lcher (eds.) . I 99,1. \4olecular gc

net ics in f ishcr ics. Revie$s i r F ish Biology i lnd Fisher ies. l : 269 399.

Cfandal l . P A. and C. A. [ . cr l l . I99] .Thegenct icsolageind wcighl at se\ual manniry bascd on ll1di!iduall)taggcd rainbow trout ( O/rc,r'li \) kri?,J ,,r li rjj. Aquucul ture l l l : 95 105.

DeInoN R. L.. li. F. Orrcll rnd D. R. Heinle. 196'1. Spalvnirg grou nd cltt.rlog of tlr!' K \ ichak Ri! er s)\tem B d stolB.r,'-. Al sk.r. Lr. S. Fish and wildlile Senice SpecialScient i f ic Repon. Fisher ic\ No. .188.

fcdorcnko.A. Y rnd ts. C. Shcphcrd. 1986. Relie\| ofsalmontrirnsf lanr pmcedurcs and susgested t|tlnsplant guidel ines. Canadjan Tcchnicul Report in Fi \her ies andAqurt ic Sciences No. l :179.

Frcnclr. R.. H. Bikor NL O,ixko and A. H,rnl. 1976. Disni-burion xnd origin of sockeve salmon (Oa.rrrr,.irr

rrl(., in o1.Ishore \iatef\ ofthe North Pacjic Oceun.lnt ! ' rnal ionxl North Paci f ic Fi \her ies CommissionBuucl in 3, t : I l - l p.

Cjedrcm. T. 1983. Genetic vrriation in quantilali\c rrails rmdsclcct i !e breeding in f ish and shcl l f ish. Aqu.rcul ture3 l r 5 l 1 2 .

Gmnt. W. S.. J. I-. Grrcia Varir lLnd F. Nl. Utter 1999. Dcfining topulation bound.rries lir fisbery managcnrcnl./, Genetics in su\lainablc lisheries n.rnagement. 1' /n.d rI S. N,iuslaia. Fishing News Books. BlackwellScience. Oxibrd. pp. 27 72.

HlL|.rche, Y. 1991. Pacilic sxlnlon in Arlantic rlaters. Inrc ational CoLrncil lbr the Erploration ofthe Sea. NirrincScience S!nrpo\ iurr 191: 1q55- 1977.

H.rnson. R 1992. Bro$r bcar ( al,:rrr ./rcror) predaiion onsockeve srlmon ( 0r. r'lrvrr fulj r.,*d) spa$,ne|s intso tributaries ofthe\\'ood liilcr 1-akc s!stem. BristolB.ry. Alaska. Nl$ter 's dre\ is . Unj \cr \ i ty of \ \ 'ashing-(D. Serrtle.

I Iard. J. J . 1995. A qurnt i tat ive gcocl ic pcrspect i le on theconseNrtion ofintrrspcciljc dn ersit). Amefican Fjsher ies Socie l ) SlmposiLr lT: 30.1 3:6.

1 lanis. C. K. I 987. Crlche\ of N(rrth Ar r rcricul sockeve salmon(Onurh| |chus r . i ' ta) b) Ihe Japancsc hiSh serssalnron lishcr,,-. 197:-8.1. C.rnrdian Spccial Publication of Fi\ircrics rnd Aqu.rtic Sciences 96: ,158 ,179.

Hedgecock. I ) . . P Sir i and D. R. Strong leds. l . 199,1. Specia lscctron: cndangered Prcilic salmonjds. Conserv.rti(nrBiolog] 8: 861 89.1.

Hendr) . A. P F [ . Leonett i rnd l P Qui n. 1995. Sput ia land rc porr l isoi t t r ing mechanisms: thc lonni l ion ofdi \crete brceding rggregat idrs of sockeyc salmoniO n.o tttv.ht \ tk rk,]). Canrdirln Joufnal of Zoologl7-r : 339-t52.

l lc l1drt . A. P. O. K. Berg and T. P Quinn. 1999. Breed:ngdate. life historv. and cnerg) .rlloc.rtion in a population of sockevc sahnon (Or.rr.l\r.lr n"r*r). Oiko\8 5 : . 1 9 9 5 1 , 1 .

322 Northwest Scicnce. Vol.73. No.,1. 1999

Hef\hberger. W. K. . J . I \ , { . M)ers. R. N. Iwamoto. W C.McAulei. and A. Nl. Sarton. 1990. cenetic changesin rhe gro$rh ofcoho salmon tOtrcorh)"rhus ki\utu h)in marinc nct pens. produced bv lcn vears of selec-t ron. Aquacul turc l i5 : 187 197.

Jcnscn- K. A. rnd O. A. Maihjscn. 1987. N{ismtory struciurcof the Kvichrk Rir'er sock.ye salDon (O".,/rrr.r{r,rdr.ld) escapement. 1983. C.rnadian Special Publication LrfFi\heries and Aquatic Sciences 96: 101 109

J6nasson. J.. B. Cierde, and T. Gjedrem. 1997. Genetic fa-rameters lbr retum r ac rnd bod) lveighr of sea ranchedAt landc sal lnon. Aquacul turc l5. l i 219,231.

Kinnison. N4.. Nl Unwin. N. Boustead and T. Quinn. 1998a.Pofulaijon spcciiic vrriation in body dimcnsions ofadult chinook \almon (Or?.rd_\r.rr{J trhaw\1scha)liom Nell Zealand and a relared Sacramcnlo Riverpopulrtim. 90 ,vear\ alicr introduclion. Canadian Journal ofFisheries and Aqualic Sciences 55: 55'1-563.

Kinnison. Nl . T. . M. J. Unwin. W K. Hcrshberger and T. P

Qumn. 1998b. Egg sirc. iecuDdiry and earl] dcvelopmenl rate of t$o Ne\\ Zcaland chinook salmon(O erh)"nchus tshar)!!t:la) populitions. with a conrparison 1() their ancestfal Sacramcnlo Ri\er popula-tion. Canadian Journal of Fisheries and Aquatic Sci-ences 55i l9:16 1953.

Kinnison M. t NI . .1. Unwin al1dT. P Quinn. 199Ec. Cirowthand sal in i ly to lerance of juvcni lc chinook salmon(O!1rh)tuh s tsl|.|d\tltld)from two inrroduced Ne\\,Ze. and populations. Cl.rnadian JoumalofZoolog) 56:2219 2226.

K$ain. W: 1987. Bidogy of pink salnon in tbe Nofh AmericanGrcal Lrkes. Americar Fishcries Societv Svmposiuml : 5 7 6 5 .

Nlaffiott. R. A. 196,1. Srre.rm calalog ofthe Wc'od Rivef sls-tem. Bristol tsay. Alaska. U. S. Fish and Wjldlill Ser,!icc Special Scienrific Rcpo4. Fisheries No. 49,1.

\I.r]r, E. 1982. Thc gro$th ofbiological ihought: diversrt).evolutlon andinhcliunce. BelknapPress.Cambridge.\frss.

McDonald, J. I98I . Ihc stock concept and i ts appl icadL'n toBriti\h Columbia \almon Iishefies. Canadian Joumalol f isher ies and Aqual ic Scicnces 38: 1657- 166,1.

Mccreeor. A. J.. S. Lane. N{.A. Thomason,l-.A. Zhivorovrky.$'. \\'. Smoker and A. J. chafrett. 1998. Nligrarionr . m i r r ' . . , l i l e h i . . ' r l r r . r r m f r - | | n l \ e j e n e r . . r u (ture oi pink salmon. North Pacilic Anadromous Fi\hComrnissiur Bul let in l : 262 273.

Mi lner.J.W. 1816. The proprgat ion a d dist r ibur ion ofrheshad. A Opciuions in the distriburion of shad in 187,1.1, U.S. Commission oi Fish and Fishefle\. Rcport ofrhe Conmissioner for 1873 ,l and 187.1-5. pp. 3tl126.

Nlinrd. R. E. and C. P Nlcrcham. 1987. Sockcye salnon(Otrcorh\n.hus netke) management in Brisrol Bay.Alaska. Canadian Spccirl Publicatiur ofFishcrics andAqualic Science\ 96i 336 -1,12.

Nlobrand. L. E.. J. A. Lich.rto$ich. l-. C. Lestelle .rnd T. S.Vogel. 1997.,A.n approach to descrbng ccoslstempe|fofmance'lhrough the e,ves of salmon." CanadianJoum l oi Fisheries and Aquatic Scicnces 5'1: 296'l-

2971.\,loulton. F. R. (cd.). 1919. The nigr.rdon and consenirtron

of sulmon. Publicrtion of the Ancrican Associatidl

fi)r the Adlancement Sc ience 8: 106 p. I -ancaster. Penn.

Ni lers. J. NL. R. C. Kope. G. J. Br l rn l . D. Teel . L. J.

L ierheincr . T. C. \ \a in\ \ ' r ighl . w. S. Crant . F. W

\\'knit. K. Neely, S. T. Lindlc) and lt. S. \\'aples.

1998. Siatu\ re l iew ol cbinook salmon f fom Wrsh

ington. Id.rho. Orcgon. l1nd Califorria. NOAA Tcch

nical Memo NMIS NwFSC-15. .:1.13 p.\ r . l , c 1 J | , p u , l ' r l r . l L l o r : , n J r h e . r l r r r i . r c o ' 1 .

lcnr: defining unique unils in potulation conser!ulion.

A nrerican Fishefies Socicly S,vmposiu m I 7. B ethcsda.

\{ D.Pclcrnrin. lt. N{.. B. J. P)pcr. Nr. F-. Lapointe. N{. D. Adkison.

- n . r L . l . \ \ . d r ( r r . l v v s . P , . e n ' , , 1 i o \ - n r l ' ^ n . n L r -

vivrl ratc\ ol British Columbiar ,rnd Alaskan sock-

eye salmon ({), k ,r'lir)rclr.t ,.J'i., slocks. Canadi n

Joumrl o l F isher ies rnd Aquat ic Scicnces 55: 2503

2 5 1 1 .qper. B. J.. R. M. Pclcmran. Nf . F. L poirlc andC. J. Walte|s.

1999. P.r l l . rns of covaf iat ion in lcnglh and rge at

I l la lur i t ] o l Br i r ish Columbir und Alaska socke),e

srlmon (0tr.r,rh /1./, rr /1.,J'i.r ) nocks. Crnadian Jour.a lo l 1- isher ieslLndAqual icSciences56: 10.16 1057.

Quim. T. P 1985. Homing and the elo lunon ()1 sockcve

salmon. aln.r,rr)r.rrr /r('*d. /lt NI. A. Runkin. (cd.)

Migrat ion\ : mechanisms and adapt ive s igni l icance.

Conlribrnions in NI ine Scicnce 27 (Supplenlent): l5l

- r66.

Quinn. T. P. and S. Bloonberg. 1992. Fecuncl i ty o lchinooksalmon (On.o/trlr.rrr r!r.?hrl.!.rd) iionl lhc \\ailaki

and Rrkria Rivcrs. Ne\ Zealand. Ne\r Zcalard Jour-nal of \1 rir1c Fresh$atef Reserrch 26: .129-'11'1.

Quinn. T. P and A. l l . l ) i f tmnn. 1992. Fishc! . /n I - l Papi . (ed.)

Aninal honing. Chxpman rnd Hal l . pp. l , l5-211.

Qujnn.T. P 1993.Arc\ ie$ ' of homing and s l raying ol lv i1d

and hatchery produccd salmon. Fisheries Rc\carch l8:

29-.1.1.

Quinn. T P and \1. J. Un\ in. 1993. L i ie h is lory pat terns oi

\e i ' Zcal ind chinook salmon (O othvchus

rrl.tlr.A.lra) populations. Clrn.1dian Journal oi lish

cr ics and Aquat ic Scienccs 50: l . l l . l -1.111.

Quinn. T. P rnd C. J. F(xrle. 199,1. Thc elTects of bod) sirc

ard \crual dift)ehisln on (hc rcproduciile beha\iour

of sockcve sr lmon. Onont\ tk hu\ ,er td. Aninr l

Beha! iour, l8: 751-761.

Qunm. T. P. A. P Hendr] rnd L. A. \Vctzel . I995.Theinl lu

cnce of life hrstor,,- radc oifi and the sire ol incubat ion gfavels on cgg s iTe vaf iat ion in sockc!c salmon(.On.orh\ t l .hu\ ' . ( tkd) . Oiko\ 7.1: , l l5 43E.

Quinn. T. P, \ { . D. Adkjson and l \ '1 . B. Ward. 1996a. Behrv-

ioral l rc t ic \ o l nnlc socke!e s.r lmon (Otro?l l i , i r r rJ

tr"rtd) under !trr)ing operalionrl se\ ralio\. Elhology

102: l0, t -322.

Quinn. T. P. J. I . . \e i lsen. C. Gan. N{. J. Unwin, l t . Wi lmot,

Cl. Culherie and F. NI. Ullcr. 1996b. Ofigin.rnd ge

nct ic st ruciufe of chinool salnron. Onco i \nc l lst\hur \tsrhd. transplanted fron Californir lo Ncll

Zer land: a l loryme and mtDNA e! idcncc. Fishery

Bul let i r 9, l : 506 5l l .

Quinn. T. P and !1. T. Kinnison. Size-select ive rnd scl !eleciile predation by bro$n berN on sockelc sal on.

Oecologia ( in prcss).

Quinn. '1. P. E. C. Volk and A. P Hendry. Nr lu la l o(ol i lhmicrostruclurc palGrns feverl precrse nomlng to na_

tal incubalion siier by sockeye s.imon (Or.!/,t)tr./irr

"./td). Canadian JourD l ()1 Zoology (in press).

Rich. w. H. 1939. Local populal ions and migfat ior i r re la

tion to the con,ienation ofPacitic salmon in the westerr

narcs and Alaska. 1, F- R. Moullon (ed.) The migra'

tion and consenation of srlmon. Publicalion of the

American Association for the Ad\ancenrent of Sci-

encc li: .15 50- Lancaster. Pcnn.Rickcr. w. E. 1972. Hereditary and enlironmental lactor!

affecting ceftair salmonid populatiors. 1, R.C. Simorand PA. Larkin (cdr.). lhe slock concept in Pacific

salmon. H. R. MacNlillan Lectures in fishcrics. Lini-vefsity of Brilish Colunrbia. Vancouver. pp. I9 |60.

Rogers. D. E. I 987. The regulalion of age rl maturity in wood

liivef sockeye salnon (Ont o*rnchus ncrkd). Canadian Special Publicalion ofFisheries lllld Aquatic Sclences 96:78 89.

Rogers. D. tr.. and C. 1. Ruggefone. 1993. Factors affecting

marinc growdr ofBfistol Ba) sockel'e salmon. Fish

cr ics Research l8: 89 101.SauDders. R. I - . l9El . At lant ic s i lnon (S.r / ,n, r r r1df) stocks

and nanrgcinent implic.rtions in thc Canadian Athn-

tic pro!inccs and Ne\r Engllllld. US,{. Canadian JouF

nal o l F isher ies xnd Aquat ic Scicncas 38: l6 l2- 1625.

Snnon. R. C. ind P A. Lark i r (eds. l . 1971. Ihe stock con

ccpt in Pacific salnon. H. R. \4acN'liUaD Lectures inFishefies. Univ. ol Brilish Cohmbia. V.rncouvcr. B.C.

Smith. H. D. 196'1. Thc scgregation ofred salmon in thc escapements to lhc Kvichak River s)stem. Alaska. LJ.

S. Fish.Lnd wi ld l i l i Scr \ jce, Speci . r l Scien( i ic Rcport Fishef ie\ . .170: I 20.

Smokcr, w. $ ' . , A. J. Ghar i r t l . and Ni . S. Stekol l . 1998. Ccnetic varation of rc(urn date in r population ol pink

salmon: a conscqucnce offlucruatirg en!ironmcnt and

dispersi\c \clection? Alaska Fishcrics Reseffch Bul-

lerin 5i 46 5.1.Su. G.-S. . L. E. L i l jcdahl , and G. A. E. Gal l . 1997. Genet ic

and en!iron rental vafiation ol lcmalc reproductive

traits in rainbow rout ( Orlcd,rrn.r&r ,r)t,r !). Aqu.tc-

uhure 15.1i l l5 12.1.Tai lor . E. B. 199l .Arevie l r 'of local rd.rp ld ion in Salmonidae,

$ith particular reference to Pacilic andAthntic sallnon.Aquacul ture 98: 185 207.

T.c] .D.J. .G.B Miher. G.A. winans and \ \ ' . S. Granl . 1999.

Genetic populalion srLtcture and origin oflilt histor)

t r -pcs in chinook sdmon in Br i t ish Columbia. Canada.

Transactions of the Ancrican Fi\hefie\ Sociely (in

North\\ est Science Fomm 323

U.S. Commissi(n l on Fish and Fi lher ies. 1E76. Rcport o l lheCom is\ ioncr lar 1873 : l rDd 187.1-5. Part 1 l l : \ \v i i i

t -n! \ in, N4. J. and G. J. Clota. 1997. Changes in l i fe h istorypammeteN in a wild population ol chinook srLmonlon(orhvrll s tshdr,\ | s.rd ) associated \lith rclcascsof hatchcry rcarcd f ish. Canrdian Journal of Fishcries andAquar ic Scicnccs 5.1: 1235-11,15.

Un!\,h, \,1. J. rnd T. P Quinn. 1993. Honing and stf.r,vingparte|ns of chinook salmon lOnerh|nchus^/rdtr fr'r'r.i) lrom a Ne\i Zealand hrtchery: spatialdistribution of stfa!s and elfecls oi rclcasc date. Ca,nadian Joutual ol fisheries and AqLtatic Sciences 50:l l 6 8 - 1 1 7 5 .

I r s i n . N l J . . \ 1 . T . K i , r i - , , , n d L P Q u , r r l u u u l \ ( < pdons 10 senelprLrit): po\t-mrturation survi!al. morphology and cncrSctics of m.rle Lhinook salmon. Canadian Journalof Fi \hcr ic \ . rndAqurt ic Sciences 56:I l l 2 1 1 8 1 .

Ulref . F. M. 1981. Bio logical cr i ler ia fbrdei in i t ion ofspecies.rnd distirct i frspecific populations ol anadrcmoussalmonids undcr lhe Ll .S. Endangered Sfecies Acl of1973. C.rnadian Journalol Fishcrie s ,tnd Aqu rtic Sci-ences 3u: 1626- 1615.

U(cr . F Nl . 1991. Biochenical lenet ics and i - ishe. ! nanagenrcnii an hislorical perspecti\,e. Joumal of I-ish Biology 39 (Supplement A): | 20.

Uucr. n M.. J. E. Seeb and L. W Secb. 1991. Complelnen-tary uscs of ccolosical and biochenical genetic datah entirying rnd conserving salnon populrttiurs.Fishcics Research I l i : 59-76.

Varnalskr lu. N. V. C. C. Wood. R. J. Elcrc l r . R L. Wi lnnn.V S. V[navsk]'. V. V \,lidanaya,rnd T. P Quinn. 199,1.Genetic differentiation ol subpopulIrions of sockeyc\alnon (Onta lt)n( hu\ .r/r.J) !vithin lakes of Alaska,Bfitish Colunrbia and Kamchatka. Russia. CanadianJournal 01 Fishcries andAquatic Sciences 5l (SUpple

menl 1) : 1.17-157.\laples, R. S. 1991. Pacific salmon. O/r.d/rlJrr.rr! spp.. and

ihc dclinidL'n of"\pecies" underthc Endangered Spe-cics Act . Muine Fisher ies Rcvicw 53: l1 22.

\\'aples, R. S. 1995. Evolutionary signilic.rnt units and theconsefv.rtion ofbiological di!ersily under the endangefed species act. Anrcrican fisheries Society S)lllposlum 17: i t l l .

wetzcl. L. A. 1993. Genetic, morphomctric and liie hi\t(rycharacter is i ics of sockclc sr lmon (On.arh\n(h \,.rta) in lhc Wood Riler Lake s,vstem. B.j\lol Bar-.Alaskr. \{aster'\ rhesis. University o1 Wrslingtdr.Scalde.

Wood. C. C. 1995. Life history rariation and popul|tiur strxcture rn sockeye salmon. Anrcrican Fisheries SocierrSyDrposiun l7: 195 216.

With lef, F. C. I 9 82. Tr.rnsplanting Pac ific Sal mon. CanrdianTechDical Repofi in Fisherics and Aqu:rtic SciencesNo. 1079.

32,1 Northrvest Science. Vol. 73. No.4. 1999