The Anomalous Surface Salinity Minima AreaAcross the Northern Gulf of Alaska and Its

Relation to Fisheries

W. J. INGRAHAM, Jr.

Introduction

The number of oceanographicactivities in the Pacific Northwest hasincreased and there appears to beample support of field activites in thenortheastern Pacific Ocean for thesegroups. Although oceanographicstudies by fisheries groups have notbeen a part of this increase, they havecontributed a considerable amount ofknowledge of environmental condi­tions and processes affecting livingmarine resources in this area. Recentstudies by the N M FS Northwest andAlaska Fisheries Center (NWAFC)provide unprecedented insight into seasurface conditions in the Gulf ofAlaska.

Background

The accumulation of knowledge ofthe marine environment in the Gulf ofAlaska has been painfully slow andaperiodic. In the 237 years since thefirst arrival of "westerners" Bering andChirikof in the Gulf of Alaska, therehave been several significant periods ofmarine investigations in the Gulf ofAlaska prior to current inshore studiessupported by Bureau of Land Manage­ment funding of NOAA's OuterContinental Shelf EnvironmentalAssessment Program (OCSEAP).

For 126 years the area was under thecontrol of the Russian-America Com­pany when numerous voyages ofexplorations and exploitation ofnatural resources (mainly marine

8

mammals) occurred. For nearly 50years, Russian officials controlled theport of New Archangel (now Sitka)and extensive traffic occurred not onlyfrom the Yukon River to southernCalifornia, but to various ports of theworld (Chevigny, 1965). Much of thelocal oceanographic knowledge thatstems from this period was compiledinto the first Alaska Coast Pilot.Davidson (1869) reported that a 0.5-to1.5- knot current was believed to flownorthward, westward, and southwest­ward along the gulf coast.

Near the end of the 19th century andin the early part of this century, a seriesof cruises was conducted using thesteamer Albatross of the U.S. FishCommission. The location and generalcharacteristics of the various offshorebanks along the continental shelf weredefined; sea surface and bottomtemperatures were obtained. Duringthis period it was generally acceptedthat water in the gulf originated fromthe Kuroshio or Japanese Currentbecause of an analogous warmingeffect the Gulf Stream had on northernEurope. In fact, the Kuroshio was alsobelieved to penetrate Norton Sound inthe Bering Sea because of the warmsummer temperatures encounteredthere also.

Extensive investigations in thenorthern gulf were conducted by theInternational Fisheries Commission(lFC) from 1927 to 1934. Winter datafrom only three lines of stations offOcean Cape, Cape Cleare. and Cape

Chiniak revealed a pronounced west­ward current at the edge of thecontinental shelf with surface flow ashigh as 55 cm/second; a markedeastward flow occurred immediatelyshoreward of this current, but flowover the shelf was generally weak andvariable. Also at the shelfedge, the coldsurface layer was determined to beunderlain by a deeper, warmer stratum(McEwen et aI., 1930; Thompson andVan Cleve, 1936), an indication ofwinter overturn recognized today as amajor process in the surface layer.

The possible individual roles of andinteractions between the atmosphericAleutian low pressure system and theEastern Pacific high pressure systemon surface flow were recognized, andextensive drift bottle experiments wereconducted across the gulf and seawardof Vancouver Island. The impliedtrajectories of the bottles indicated abroad sweep of cyclonic flow over thecontinental shelf with a strong onshorecomponent around the entire gulf.However, the source of this flow wasstill considered to be the Japanese(Kuroshio) Current (Thompson andVan Cleve, 1936) until the transpacific,largely locally formed, SubarcticWater Mass was identified by Sver­drup et a!. (1942).

W. J. Ingraham. Jr .. is with the Northwest andAlaska Fisheries Center. N M FS. NOAA. 2725Montlake Blvd. E.. Seattle. WA 98112.

Marine Fisheries Review

During 1950-52, the Pacific Oceano­graphic Group of the Fisheries Re­search Board of Canada conductedfour offshore oceanographic cruisesfrom the southern end of VancouverIsland to the northern end of the QueenCharlotte Islands in an attempt todefine the role of this area in relation tothe oceanography of the northeastPacific Ocean and to define subsystemswithin the Subarctic Water Mass.Doe (1955) showed the continuity andbroad offshore extent of coastal andoffshore water masses in the easternand northern parts of the gulf and (onthe basis of data from only a fewstations) indicated that these watermasses narrowed considerably alongthe western side of the gulf, suggestingthe presence of a boundary current.Seaward of the offshore water mass arather vague outline of a mid-gulfwater mass was presented, defined by afew widely spaced stations obtainedaboard the U.S. Coast Guard vesselOgalala in 1936 subsequent to theIFC studies. Thus, only 20 years ago,the nature of the southwest flow out ofthe Gulf of Alaska and conditions inthe mid-gulf area (other than at thesurface) could be ascertained fromthe limited data at several oceano­graphic stations.

INPFC Studies

Our present concept of the physicalenvironment of the Gulf of Alaskastems largely from the extensiveoceanographic studies conductedunder the supervision of the Interna­tional North Pacific Fisheries Com­mission (INPFC) from 1953 andcontinuing in varying scope andintensity up to the present. These andother concurrent studies, such as theNorth Pacific Expedition ( ORPAC)in 1955, provided the extensive datarequired to show the transpacificcontinuity of flow into the gulf and theorigin of local water properties.

Summaries of oceanic environment­al conditions from 1953 to 1959(Dodimead et aI., 1963) and from 1960to 1971 (Favorite et aI., 1976) and ofconditions in the Gulf of Alaska

May-June /979

(Ingraham et aL') form the basis ofmuch of our current knowledge ofoceanic ~onditions. There is a greatlyincreasing body of informationconcerning physical conditions in thecoastal regime at the head of the gulfas a result of OCSEAP and otherstudies (e.g., Royer, 1975; Royer andMuench, 1977; Muench et aI., 1978;and others).

General Conditions

Changes in environmental condi­tions in the Gulf of Alaska are largelycharacterized by water temperatureand salinity-the former largely re­flects cycles of warming and coolingcharacteristic of high latitudes andresults in relatively uniform condi­tions over large areas except incoastal regimes where snowmelt andtidal mixing results in lower valuesthan in offshore areas; whereas, thelatter largely reflects imbalances be­tween evaporation and precipitationas well as seaward discharges ofsnowmelt and runoff from the coastand mountain ranges ringing the gulfthat result in marked seaward gradi­ents and contribute to a salinitymaxima area in the central part of thegulf. The general nature of the perma­nent flow is cyclonic (counterclock­wise) and, as coastal dilution inspring from the eastern side movesseaward, it is advected slowly north­ward around the gulf. During sum­mer this offshore flow of dilute waterin the eastern gulf is further altered bylocal northwesterly winds whichcause an Ekman transport 90° to theright of the wind. These seawardintrusions were detected by Favorite(1961), Dodimead et at. (1963), andothers, who reported offshore continu­ity of coastal plumes of dilute water inexcess of several hundred kilometersalong the northeast Pacific coast.

Sea Surface Studies

During a WAFC oceanographic

'Ingraham, W. J., Jr., A. Bakun, and F.Favorite. 1976. Physical oceanography of theGulf of Alaska. NMFS Northwest and AlaskaFisheries Center, Seattle, Wash., ProcessedRep., 132 p.

cruise aboard the NOAA researchvessel George B. Kelez conducted inspring 1972 to ascertain environmentalconditions in the vicinity of Portlockand Albatross Banks south and east ofKodiak Island in the western gulf, aband of surface salinity minima «32.5

%0) of unknown origin was discoveredalong a 500 km stretch generallyparalleling the edge of the continentalshelf (Favorite and Ingraham, 1977). Itwas assumed that this feature wasprobably continuous to the eastwardaround the head of the gulf andmarked the boundary between coastaland oceanic water and could serve as aguidepost or path for migratingsalmon.

A U.S.-Poland cooperative fishing­oceanographic survey aboard thePolish research vessel Profesor Sied­lecki in July 1977 provided an oppor­tunity to trace the band of salinityminima eastward. Data from a ratherextensive grid of stations clearlyindicated a marked separation at theeastern side of the gulf of surface waterof salinity <32 %0 near lat. 58° 30'N,long. 138°30'W (Fig. I)-one branchextending northwestward along thecoast over the shelf, and the other anoffshore intrusion that protrudedwestward across the gulf as a band ofoffshore salinity minima. The latterwas the first known indication of theexistence of an offshore band ofsalinity minimum in this area.

At the head of the gulf, this offshoreband was clearly separated from theextensive dilution caused by the runofffrom the Copper River, one of the fivelargest gauged rivers in Alaska and theonly one of the five that discharges intothe Gulf of Alaska; with an averageannual discharge of 8.3x 106cfs/ year,it ranks third (Yukon, 62.3x I06

;

Kuskokwim, 16.4xI06; Kvichak,

6.4x I06; Kuzitrin, 4.4x I06

)2.

2Seifert, R., and D. Kane. 1977. Effects ofseasonability and variability of streamOow onnearshore coastal areas. In Environmentalassessment of the Alaskan Continental Shelf.annual reports of principal investigators for theyear ending March 1977, Vol. 14. Transport. p.96-250. U.S. Dep. Commer.. NatL OceanicAtmos. Admin. and .S. Dep. Inter., Bur.Land Manage., Boulder. Colo.

9

Although a mean daily discharge ofapproximately 10,000 cfs usuallyoccurs from November to April, valuesof over 100,000 cfs may occur by Juneand continue into September. Thus,the Pro!i'sor Siedlecki data in Julv1977. r~nect only the initial stages ~fthe annual discharge of Copper Riverwater into the oceanic regime. Thisseparation of dilute surface water in theeastern gulf is significant because itcould determine whether fish eggs andlarvae along the continental shelf andslope in this area would either becarried offshore or confined inshore;whereas. in the northern and westerngulf planktonic forms over the shelfand slope would be confined entirelyinshore.

The western gulf may be even moresignificant as a mixing zone of theminima caused by the Copper Riverplume and the offshore salinityminima area as they merge and nowsouthwestward out of the gulf. Thus,at any specific time or specificlocation either source may dominate.Unfortunately, the Pro{esor Siedleckidata are not adequate to detect theextension of the offshore salinityminima to the western side of the gulf,but fragmentary portions of one orboth minima are evident in some datafrom OCSEAP cruises conducted offKodiak Island during 1977. An area ofsalinity minima near the shelf edgewas well defined in March with values< 32.0-32.2%0 (much lower than inMay 1972), detectable in July. andstrongly evident in September as apronounced offshore minima area withvalues < 31.8 %0.

During October the minima areawas poorly defined as salinities increas­ed slightly, but by November it becamemore pronounced as the salinities oversome of the shallower banks atmidshelf increased as a result of wintermixing and turnover. Thus, east ofKodiak Island the salinity minimaoccurs year-round and cannot beattributed to a single local, seasonalcoastal source of runoff, for example,the Copper River-but a combinationof local and trans-gulf sources.

-------

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oNM

Nltl

10 Marine Fisheries Review

L --lI.- ..J.-_-'-_........_.....&_..:=~54°

56°

32.2 %0. Considerable complexity,with numerous lenses, offshoretongues, and small scale features was

200 m.

Dlxoiir·········ENTRANCE

......

I,~

:/.....

. :

Figure 2.-Surface salinity(%ojtaken from !'IOAA R V i.til/er Freell/(J/I. 25-:'0August 197R. and cruise tracks along which continuous salinity measurementswere made. Arrows indicate the rrohahle direction of mmement of thc majorsources of dilution into the onshore area. .

were quite dilute (Fig. 2) with surfacewater salinity over the shelf of 31.3­32.0 %0 and offshore water from 31.6 to

1380 1360 1340 1320

W~--------,--------r-------r 59°N

The area of low salinity detected atlat. 55°-56°N, long. 139°W during theProfesor Siedlicki cruise (Fig. I)suggests another source. The lowsalinity values in this area are believedto originate from seaward discharge inspring of coastal water out of DixonEntrance (lat. 54° 30'N) and/ or QueenCharlotte Sound (lat. 51°-52°N).Favorite (1961) has shown that suchplumes reach to at least long. 137° W.

The increased data coverage in1977 thus provided knowledge of theseasonal complexities in the continu­ity of surface salinities which, al­though subject to mixing and stirring,reflect surface water movement. Withthis background, plans were made totake an opportunistic look at as muchof the area as possible in summer1978 during a NWAFC fishing cruiseaboard the NOAA research vesselMiller Freeman in August-September.As a result of a meeting at the NWAFCon 13 July 1978, with scientists fromthe Korean Fisheries Research andDevelopment Agency who were aboutto conduct operations in the northerngulf aboard the Korean research vesselOh Dae San, a cooperative plan toobtain surface salinities was approved.Surface water samples obtained in thenorthern gulf during August fromaboard the Oh Dae San would bedischarged at Kodiak for analysis byNWAFC personnel when the MillerFreeman reached Kodiak in Septem­ber. Subsequently a salinograph unitwas installed aboard the Miller Free­man during an August 1978 port callin Seattle in order to obtain acontinuous record of surface salinityalong cruise tracks normal to thecoast at the head of the gulf.

Because this study aboard theMiller Freeman had to be a part of afishing cruise, observations were ob­tained during two different periods ofvessel operations. From 25 to 30August 1978, the salinograph wasoperated during hydroacoustic-fishingtrawl transects over the shelf during theday and on offshore excursions duringthe night between Dixon Entrance andSitka. Surface conditions in this area

Mar-June /979 /I

cJCb

57· N

56"N

59" N

6O"N

138" W140" W142" W144· W1460 w

v148" W

~;f

150" W

i#

152" W154·W156"W....."-'

56· N

55° N

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Figure 3.-Surface salinity ( %o) taken from NOAA RV Miller Freeman. 1-6 September 1978, and cruise track along whichcontinuous salinity measurements were made. Arrow indicates the probable direction of movement of the major sources ofdilution into the offshore area .

~<:",'~

evident. The predominant featuresalong the southeast coast are the salineoffshore water (>32.2%0) and tonguesof dilute water «32.2%0) which pro­truded as much as 135 km into theoceanic water from two major sourcesof dilution, Chatham Strait (near lat.56°N) and Cross Sound (near lat.58°N).

Much small detail is evident by thecontinuous sampling in the range of0.1-0.2%0). Offshore minima werepresent where the seaward tongueswere either cut off by mixing or turnedwith the flow beyond the shelf; but nocontinuous, alongshelf band of salinityminima was evident. Normal oceanicsalinities >32.5%owere not encounteredalong any of the cruise tracks offsoutheastern Alaska.

Observations at the head of the gulf,the area of prime interest, wereobtained by requesting a 3-day delay inthe scheduled arrival of the MillerFreeman at Kodiak. Data were ob­tained from I to 6 September 1978along 2,780 km (1,500 miles) ofcontinuous zig-zag tracklines at aspeed of 13 knots as the vessel wasenroute (Fig. 3). Hourly water sampleswere taken and analyzed aboard shipwith a precision laboratory salinome­ter (Autosal J 8400) and salinity andtemperature values were digitized fromthe traces by hand to show linear trendsand peaks on a 5-15 minute interval(about every 2-6 km). The analysis ofthese data, probably the most detailedand synoptic surface salinity record forthe area, revealed several interestingfeatures.

Along the northeast coast the trendof the isohalines was generally parallelto the shoreline apparently reflectingalongshore processes in the absence ofmajor freshwater sources. The domi­nant feature is the seaward penetrationof the low salinity (31.6%0) plume fromthe Copper River area extending 80 kmsouth of the shelf break well into theoceanic regime of high salinity(>32.6%0) water.

3Mention of trade names or commercial firmsdoes not imply endorsement by the. ationalMarine Fisheries Service, OAA.

May-June 1979

In July 1977 this plume was confinedlargely to the shelf area westward of theriver mouth. The sharpest frontal zone(a change of 2-4%0) occurred at thehead of the gulf; downstream to thesouthwestward both minima andmaxima were evident along the shelfbreak. The seaward terminus of theplume reflects an anomalous eastwardmovement in the proximity of theAlaskan Stream, a narrow, high velo­city (50 to 100 cm/second) boundarycurrent which is known to flow in asouthwesterly direction along thecontinental slope area. As evident indata from other years, intense mixingand stirring at the surface just east ofKodiak Island (lat. 58° N, long.148°W) has largely eradicated most ofthe dilute plume south of lat. 58°N.

Unfortunately vessel-time limita­tions did not permit steaming farenough into the central portion of thegulf to adequately define the offshorefeatures; however, fortunately, addi­tional data from the University ofAlaska research vessel Acona andfrom the NOAA research vesselOceanographer obtained during thesame time period, were made availableto us (Fig. 4A). The former permittedclarifying distributional patterns at thehead of the gulf; the latter providedevidence of a seaward extension ofdilute water from the eastern side of thegulf at lat.56°-57°N to long. 143°Wwhere it terminated at a salinity frontoriented in a north-south direction.

Normal cyclonic circulation in thegulf would indicate that the dilutewater of salinity<32.2%0 should havemerged with the eastward componentof the Copper River plume by fall.Whether the resulting water masswould eventually move northward tothe head of the gulf before turningsouthwestward or turn westward nearlat. 58° , it is obvious that bothsources will contribute to the offshoresalinity minima east of Kodiak on ayear-round basis.

Although surface temperature infor­mation is the most readily attainabledata base to investigate ocean condi­tions and anomalies (e.g., the data areeasily measured from an instrumenta-

tion standpoint, routinely collected bymost vessels, and now supplementedby gradient information in cloud-freeareas of infrared satellite photos), it isstrikingly apparent (Fig. 48) thatneither of these sources of dilution northe patterns of flow suggested by themare as clearly evident in the tempera­ture distribution.

One feature readily apparent near­shore between lat. 56° and 57°N at theeastern side of the gulf is the colder (2­4° C) water associated with snowmeltand runoff; but, perhaps, more signifi­cant is the extensive seaward protru­sion of the 14°C isotherm in this areathat is similar to the 32.2 %0 isohaline.Nevertheless, in the offshore area, thereis only about a 1°C change across theentire gulf with the eastern gulf beinggenerally warmer. Further, if oneaccepts the significance of 0.5°Ctemperature differences, the warm(>14°C), southward protrudingtongue offshore in the northern gulf atlong. 146°W, which occurs at theeastern side of the area of the offshoresalinity minima, appears to support theidea of an eastward flow of CopperRiver dilution near lat. 58° N as sug­gested earlier. Finally, the possibilityof the trans-gulf band of 14°C waternear lat. 58°30'N being a harbingerofatrans-gulf salinity minima band isintriguing.

Discussion

The question of the existence andnature of the offshore salinity minimaarea across the head of the gulf and themixing and merging area near lat.58°N at the western side of the gulf isnot completely resolved and willrequire more intensive observationsalong even more closely spaced track­lines and repeated surveys from monthto month. Certainly the data presentedindicate that the offshore salinityminima area eastward of KodiakIsland represents a convergence ofsurface water from two distinct sourcesbut at times only one of these sourcesmay be represented.

Now that presence of this surfacefeature has been clearly established, itis easy to find evidence of it in previous

13

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«

•~L_....... ....... ....... ....... ............._,,"-__......__---,

'Pacific Oceanographic Group. 1958. Physical3nd chemical data record :'<orth Pacific surveyscontinental shelf and Gulf of Alaska July 22toAugust 10. 1958. Fish. Res. Board Can ..Manuscr Rep. Ser.. Oceanogr I.imnol 29.107 p. + append'Dodimead. A. .1 .. F M Boyce. f KChippendale. and" .1 Hollister 1961.Oceanographic data record "\orth Pacificsurveys May 10 to July I. 1901 Fish Res.Board Can .. Manuscr Rep. Scr.. OccanogrI.imnol 101.337 P

data, which in most cases were toofragmentary to justify assuming theextensive continuity that apparently z z z z z z z

exists. (It should be pointed out that' Sl $ ~ ~ :g ~ ~such data were obtained largely to ~ r--.:;:...---..:;:..---....:;:.---...:;:---~...:;:----:;:.-:---'define large-scale features of oceaniccirculations in the eastern Pacific r'Ocean.) For example, data for 19 July • I) ~ '\,,,l'lto II August 19584 (Fig. 5) reflect ~ ~ 0 .q J

surface salinity minima in several lines .. l), . /

of data normal to the coast at the head ~7of the gulf that is not evident on the /map of surface salinity presented in ~ /Dodimead et at. (1963: J33) because of J

isoline intervals and map scale. Furth- \",-/"'-, //er. this feature can also now be detected <.~ ,/

Iindatafor22MaytolOJunel96J5off • F'\"/Kodiak Island and other more frag- ~ (mentary data sources. Although the l~/ ._-.,overall patterns of surface salinity are W \markedly different, the presence of the • \ ....,,___ \_~ )band of offshore salinity minima is ~ '\ /readily apparent. 1 (

A schematic of the effect of the ~ \annual cycle of dilution is presented • J "'-_~)

/with likely locations by season of the ~ --./ //extent of dilute water (Fig. 6). During (_~_----/;////spring the initial movement offshore ' .__ ;~-- _---/aoccurs at sites of extensive runoff. Insummer, spring dilution has extendedfarther offshore in the eastern gulf withsome contributions from the south. Byfall, runoff sources are diminishingwith the advent of freezing, anddilution that entered the area from thesoutheast is traversing the gulf. whilespring and summer dilution from theeastern gulf has reached the easternKodiak mixing area. Here, overturnand mixing produce high salinities onthe shallow shelf areas-thus the off­shelf minimum is most pronounced.

Finally, in winter there are no majorsources other than a general area

/4 Marine Fisheries Review

contribution from precipitation at seawhich IS not considered. Mixing isincreased both vertically and horizon­tally but spring and summer dilutionfrom the eastern side of the gulf is stillsufficient to maintain a remnant of thetrans-gulf salinity minima area. Thissuggests year-round convergence in theoffshore band of salinity minima anddivergence in the band of salinitymaxima that occurs shoreward of theminima at the head of the gulf.

Relations to Fisheries

For over half a century fisherybiologists have been trying to ascertainhow Pacific salmon, Oncorhynchusspp., find their way In the ocean.Although the extensive INPFC studieshave fairly well documented theoceanic distribution of various species,little is known about seaward migra­tions of smolts or shoreward migra­tions of adults. The available evidenceindicates that the seaward migrationpath of nearly a billion juvenile sockeyesalmon, 0. nerka, in the VancouverIsland-Queen Charlotte Sound area isnorthward along the coast and aroundthe Gulf of Alaska to the KodiakIsland area, where they diffuse into theoceamc regime.

Since downstream migrations occuras snowmelt and runoff commence orpeak, it is reasonable to assume thatsalmon, particularly the sockeye, couldhave some affinity to river plumes andremain within their influence as long aspossible. This would suggest thatseaward migrants from the above areamove offshore and into the central gulfsouth of southeastern Alaska, therebyavoiding not only the necessity ofintermingling with stocks In thenorthern areas, but also the encounterof seaward discharges and associatedwater characteristics of innumerableother coastal streams.

Perhaps most significant is the factthat such a migration path would serveto isolate these salmon from thejuvenile sockeye salmon from theCopper River until the latter hadentered the oceanic regime.

Keys to shoreward migrations are

May-June 1979

z z z z z z~ ~ !; !l f; !l);~r--""';'---:;:""--":;""--":;:"--"""--""""'"""'r~

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complex because widespread oceanmigratons involve environmentalconsiderations from a wider area thanconsidered here; however, the datapresented here indicate for the firsttime that salmon returning to theCopper River can find strong clues tothe river discharge over 200 km sea­ward of the river mouth. As a result ofthis, studies on the oceanic distributionand migration of salmon in this areashould no longer be undertakenwithout extensive knowledge as toimmediate location of seaward exten­sions of coastal or river plumes.

Obviously it is difficult to relatesurface phenomenon to behavior ofground fish, although it can be shownthat surface manifestations of subsur­face flows are common, i.e., upwellingwherein offshore transport of surfacewater by winds requires replenishmentof mass from subsurface water alongthe coast. This causes an inshore flowat some point along the sea floor that issubsequently readily apparent at thesurface in lower sea surface tempera­tures. However, those species ofbottomfish having pelagic eggs andlarvae can be greatly affected bysurface conditions.

Pacific halibut, Hippoglossus Slen­o lepis, for example, have two knownmajor spawning grounds: I)South ofQueen Charlotte Island, and 2)offYakutat. Eggs deposited off the shelf atdepth, 200 m or greater, in winter riseto the surface layer in spring. Larvae,whose survival is dependent on settlingout of the water column in coastalareas, are at the mercy of surfacecurrents during spring and summer.

Heretofore, it has been assumedthat the general surface winds andcyclonic flow in the gulf have providedmechanisms wherein surface transportalong the coast has been shoreward,thereby contributing to, if not respon­sible for, the successful survival ofhalibut larvae. Obviously evidencepresented here indicate some mechan­isms that are not conducive to the

/6 Marine Fisheries Review

d' ,4

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.~ ,.'3C.,q, -c

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Literature CitedC'hevigny. H. 1965. Russian America. The

Viking Press, . Y., 274 p.Davidson, G. 1869. Report of assistant George

Davidson relative to the resources and coastfeatures of Alaska Territory. U.S. CoastSurvey Report 1867. App. 118, U.S. Gov.Print OfL, Wash., D.C.. p. 205.

Dodimead. A. J., F. Favorite, and T. Hirano.1961 Salmon of the North Pacific Ocean. PartII. Review of oceanography of the Subarctic

survival of the larvae and must beconsidered in any study of this species,or other groundfish species withsimilar early life stages. One can easilyextend these remarks to concur as tothe ultimate fate of larvae of decapodssuch as king crab, Paralithodescamtschatica, and snow crab, Chion­oecetes spp., and pandalid shrimpwhich are also abundant along thisstretch of coastline.

Finally, it should be obvious thatany hydrodynamic-numerical or othercirculation or water transport modelsdeveloped by OCSEAP and othergroups to forecast or to ascertain theultimate fate of pollutants frompotential oil drilling sites in this area,must include aspects of all the condi­tions and processes associated with theyear-round occurrence and variabilityof this phenomenon.

Acknowledgments

I thank Felix Favorite, NWAFCResource Ecology Studies Coordina­tor, for instigating this study; KimYeon-Hwan, Korean Fisheries Re­search and Development Agency, forsurface water samples from the OhDae San; Henry J. Niebauer from theInstitute of Marine Sciences, Univers­ity of Alaska, and Ronald K. Reedfrom the National Oceanic and Atmo­spheric Administration, Pacific MarineEnvironmental Laboratory, for datafrom the Acona and Oceanographer,respectively; Robert L. Charnell,Pacific Marine Environmental Labor­atory for access to OCSEAP cruisedata: and Roger E. Pearson ofNWAFCfor editorial comments.

Mar-June /979 /7

-.00

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130" 1250 W

- SPRING

~ SUMMER

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Figure 6.-Schematic diagram of the seaward extent of the major effects of coastal dilution by season.

1550

'·:ro,<'O"~

'''"'~ \ I~~.~)})S,ft'{r .. I

~f~~~} t'\ -,~.{;~".. 0-

' "", '." ';1 - 50I '3.1<1,.--- .."'r'~_~__~ h ...__.;- ._, ';;:~ 'ft.~~~3~...~ ----~ :"t<! ~ .. _",!"J ;__ 'Pon .. 11>r,", • I''''f) _\~ ~

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.:..,:;.r,..,omo

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Pacific Region. In!. North Pac. Fish. Comm.,Bull. 13, 195 p.

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Favorite. F. 1961. Surface temperature and sali­nity off the Washington and British Columbiacoasts, August. 1958 and 1959. J. Fish. Res.Board Can. /8:311-319.

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