iiatachtesene paren rerels pat tp Se ome . ‘ ‘ ¥ i ' > } - PROCEEDINGS OF THE NATICNAL SHELLFISHERIES ASSOCIATION Annual Meeting Atlantic City, New Jersey August 21-24, 1950 5 MOTTAIDOeeA caremeriiscne Iasorat.. 14 Gees AS-IS semwA NATIONAL SHELLFISHERIGS ASSOCIATION 1950 Officers PresidenGier vac atveasicceveoesvvade Nelson Gowankoch Vice-President. eseesoeeoee#senveees eevames Be Engle Secretary... SO Rae NM mia ave lela eis’ gets Te Chestnut _ PSE Behe ue eee ott urea ca David H, Wallace Committees Nominating Committee Joseph Glancey, chairman Victor L. Loosanoff Resolutions Committee Thurlow C. Nelson, chairman David EH, Wallace Mee Che g taut Program Committee Paul S. Galtsoff, chairman if, G. Walton Smith James B,. Engle Committee to survey regulatory or legislative powers to control the introduction of non-indigenous Species of oysters. Paul S. Galtsoff, chairman James N. McConnell David H. Wallace worTatD aah eisauersauene a0 “oser” 7. paeoltio saneacnsnanessnn 20QBE8 dooknswoo Moalek ybaeases. elas . of eartbes s+ PHP ESROERAHF: ducdeed an Wee eost fe’ all bivad. SHA eee ere.” raaeseeceae tote ry 7 rt aeat i immed ect immed gait samt mOt, annitads yeouald age! py otrecod al asotiads . enosiel «0 wot eoal lal. «if biw Jind esdO 4% - .epd¢ temo aoe ametl Bf 9 etiosiisd oe ft Adind- ndgiaw S Lie Boa aeiad? eitase Yisanotq edasrohar of ootactomos Selzeiald antinnt $29) Ven nolson etalygoudos tert Bre oy OF nelidetg art te + HroXte od @otede anion wy rteltifoade ed? to Ila al a Bnvtoqmoo pntvacl of fd eUtIaubms add ot Koltosovong, “HON MO BOLOUIe dons euntinos oF 9e%% Belvotatodel oltieti seb HetaLlely tc astmom blod Yaa 88 Roloodn meg ae | fami, fait aMtor fest .0) wr) Cut? eeenifay’ .. blvad Pandeots 4 oh edT to aoliaevaed Tein) tate eda ts hetcoba pots stopaga etolaeGg TREASURER'S REPORT NATIONAL SHELLFISHERIES ASSOCIATION June 1, 1949 - August 18, 1950 Cash on hand and in County Trust Co., Annapolis, June Ly 1949 eeeseeoeeseevpeoeee sees ee @ Receipts: Membership dues June 1, 1949 - June 1, 1950... TOG aie) eceke Cash on hand - County Trust Co., Annapolis June ce 1950 eeeeoeoevseeesteeveeerveesv eee Receipts: Membership dues, June 1, 1950 - August 18,1950 Total eeese Disbursements - June 1, 1950 - August 18, 1950 Refund - membership dues H. J. Heinz ‘2,00 Bank charges @eesveveeveevaeeeeeveeeoeeeoevee 80 @ MOA ce Cash on hand - County Trust Co., Annapolis, August LB 1950 eoeeseeresreeeees cece Respectfully submitted David H. Wallace Treasurer Audited by: 12 158.65 Bee 101.00 3 259.65 259.65 = & 66,00 & 325.65 oMeeen Ok Sa hl MO uc Slade Mahal | se vee vy m moan at sanvesant WOTRATOOBEA eciAmeTLIENS LiMOTTAM oxet ial gouauh ~ eer “ ocunit ai Loqanna ge00: dsauaT Javed tt bas Pnae; 88,85L § + dda Saiegiempnets © %s 90: ros sd onus, =: ce . aint oo OSOL gf ore ~ 2991 Qt onut seubh qider 80.088 6 sees intot a —ehLogsanA 4.00 deurT Yangou © baad A 88,068 o RUMRUNN SSeS PARSE SOS O osel: af eal (Bs0d_ se ose, Sf deugwis ~ oaer ,f enul (eon qines GB.08E Go gene beso? * “adit oes ght saunvd ~ 0892 sf enut = fae 00.82 ante .t .4 sevh. qidetedmen-) Dm t £0.c 2 «hal Ades dpbeabahanatatetadelntbel: 9: 31 cog aade . | sekfoqanas 200. Joust r yiaso - baad ¢ ri CPs oacit <6 SeunuA Tia i ike hetiindye yiiuisoe son eoel{a.. .ii blva sotmeaen? INTRODUCTION OF NON INDIGENOUS SPECIES OF OYSTERS Report of the Committee submitted to the National Shellfish- eries Association at the Annual Convention, August 22-24, 1950, at Atlantic City Introduction of any foreign plant or animal presents a Serious problem which requires careful study and consideration before final, and frequently irrevocable, action is taken. It is true that there are many useful plants and animals which were introduced from foreign countries. Their cultiva- tion and propagation materially contributed to the progress of American agriculture. Yet it is equally true that many unde- sirable pests were unwittingly brought in to our continent, or were introduced with the valuable plants and animals as their parasites or commensals. Suffice to mention the water hyacinth, the spread of which, in the rivers and ponds of the southern states, interferes with navigation and fishing, and the Euro- pean carp which proved troublesome and undesirable in the Ameri- can habitat, while in Europe the fish is highly esteemed for its meat, and is extensively propagated in ponds. The combat of any pest presents great difficulties, for control operations are, aS a rule, expensive and frequently ineffective. The difficulties arising from the introduction of a non indigenous species are many. The introduced organism may com- pete with the native forms, and in a course of years, may re- place them. An exampie of such a case is the introduction of the Fortuguese oyster, Gryphaea angulata,to the Atlantic coast of southern France where it gradually replaced the native, and more desirable, Ostrea edulis. Various pests and destructive enemies of native fauna and flora may be introduced with the foreign species. The spread of slipper shell, Crepidula, on the West Coast of this country and in Europe, the introduction of oyster drill, Urosalpinx cinerea, in England and Europe, and the spread of the Japanese conch, Tritonalia japonica, in the state of Washington are well- known examples of this situation. Species which, in its native country is harmless, may be- come highly destructive in a new environment where its propa- gation is not checked by natural enemies. Examples of such cases are numerous. The most spectacular ones are the spread of the giant land snail, Achatina fulica, a native species of East Africa which, more than a hundred years ago, was intro- duced to some of the islands of the South Pacific, and in re- cent years, has spread through the Dutch East Indies, Phillip- pines, iuariannas, and Caroline Islands, and through mail ship- ment reached Hawaii in 1938. Vast destruction of vegetables and decorative plants marked the spread of this voracious snail. LLL Bi URN Aan EO Sk ge exaTeYO 40 Vale BvoMOTIET toM FO MOTTOU - mfeltifedd fecoltall end of Bettinidus aettimnoed edd OSOL .d8-S8 JanguéA .mofimevac) Ieuan’ eld Je noliato 2 . 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Bee ‘effew eta molanidess To otade oid af ao dcoasl. 22 ano fat. gf ' aoldaudie sind to selquaxe tm ~ed yen ,eselerred ef ytiavos ovlden oil al ,doidw soloed ‘eaqotwq etl exeiw dnemnoitlyae wen #2 ai evisounstaeb vias Ce gdowa- to eelqmexd -.¢etmons Latetean yd Dejloero gon @ sf beets oft om seco talussioo ys Jeon eT | -evotenun ots 5 to ealooege ovisad © -@B2ihe% aitjatoA .ftene Baal Jaely “eotjal sew ,oas omey Beibnur 9 aand evton. giotiw ebtatA «een al baa: ,oltioal djvoe et to ebhasfel odd Yo emos oF “eq ki int .aelbet teak dbied edd davyonids beeaqea aed ,.eteey: “eqida ilem dguortd haa: -ebnatel emtiowed bos. .eannebasa. . _.. wefdavegev lo sohtowtiesd sceV.- .8é@l nt ttawall bedoae “,tlane enclostov ald’: to baeiqe edt Beslwem etnelq sv iteage) anh planting of oysters from other areas whenever, in the opinion of a state official in charge of fisheries, such importation might be harmvul. The States of Maine, New Hampshire, Massachusetts, Rhode Island, Pennsylvania, Delaware, Georgia, and hississippi have no laws restricting or regulating, in any way, the importation and planting of foreign shellfish. Among the Federal Laws relating to the protection of wildlife, the so-called Lacey Act (May 25, 1900, 31 Stat. 187- 18 U.S.C. 395), authorizes the Secretary of Agriculture to regulate the “introduction of foreign birds or animals" in localities where they have not heretofore existed. With ref- erence to the words "birds or animals", the meaning of the phraseology of the Lacey Act has not been extended to include fish or any .quatic invertebrate. The U. S. Public Health Service exercises supervision over the importation of species of mollusks which might be con- cerned with the transmission of human disease. This refers primarily to the exotic species of fresh water snails some of which are known to be intermediate hosts of Trematodes. According to the incomplete information the Committee was able to procure, at present, foreign species of oysters and clams have been introduced in the following localities: A few bushels of seed of the Japanese oyster, O. sigas, were ~ planted in Barnstable Bay on Cape Cod by the Woods Hole Oceano- graphic Institution. The oysters are growing very rapidly and have reached six inches in length. A small number of the Euro- pean oyster, Ostrea edulis, was planted by V. 4. Loosanoff in liaine waters and attempts were made, by private persons, to introduce some of the Pacific clams including the giant Geoduck clam into Maine waters. In the past, plantings of the Japanese oyster were attempted, on a small scale, in Louisiana, Alabama, and North Carolina. So far, the Japanese. oyster has not established itself in the Atlantic and Gulf waters, and there is no evidence that Japa- nese conch, or other enemies associated with the Japanese oys- ter beds, were brought to this coast. Continuous attempts to plant Japanese or other foreign species of oysters in the coastal areas of the Atlantic and Gulf States may eventually result in the establishment of for- eign shellfish in these waters and the displacement of the na- tive eastern oyster. In view of the serious consequences to the oyster industry that may result in a haphazard introduc- tion of exotic species, we propose that a committee be appointed to study the problem from various angles. We further propose that the National Shellfisheries Association place itself on record as having recommended the adoption, by all Atlantic and v ‘ebetqnesis stew soteyo eeonsqal odd 0 aanlineliq .desq edd a] motnitgo sat at .covens MOkd ad atoqm! ou ho) w arete tedio mort ans: efelt Io ontedo at Lalor eboih ,atiegmdomersil ,onideqnst weil yorled to aetade ex] evad laqleeleatt Soe ,alatoed ,oraveled ,stoaviventad A molisixoqm! ett ,yaw Yar al wyaldaluxer to goitolwdeet sw elaltiloie mpterst to getdas ‘to sottostony edt oF yattolor avai Larebe% edd nom “POL sdasc £5 ,00@Z eS yall) Jos yeos- belieo-o2 oft otk o2 tut foo lig’ HO YUeion90e edt cestrodgus , (80S Oe at "elsmiae to ebtid aatetot to aolioubortn " ‘end om “let dvi; .bedaixe etotodeted ton evar vert prety sett. ei? Io gninsem ad? ."afemine +o shrtd" ebaow edd of 5 ohufont of hehaetxe need ton esd #2 yeosl eft to yRofe -otardedreval olieup . qne'4 . a: aa motatvreque Beetotexe estviec itfesll alfdwi .2 UL ' “neo ed sdgin doldw adeatiom 10 eetsede to noltisttogmt edt atetet eliT .eemestd aemud Io molaetmanetd odd Ad Bw! to emon allene tefew desert to colooqe otioxe edt od yf -esebotametT to etcon elelbentetal ed of awvoml ef saw ceddinnod edt soltomiotat osolqmosnal edd od antbzo Bis eisteyo to eeloece nptotot yiseceta ga eo TeIONg ¢ -A seeltifwool gntwollot oft a? bsovboutat nesd evad 4 ’ oftew S .0 «tedeyo ssenagel ot’ to bese Yo sled ‘ wONBeD9 efolt # ol" old ¥¢ bod eqe2d ao ved elfdatenxefl Bh Bua Yiblqet ytev snatwors ove cioseyo edit ,.noliudivent: “O71 etd to gedmun f[fome A .citgnel at eonom? xfs beciones QE Diowmeool 4. .V yc: bednalq enw eeilube see «103 By Ot, ,BaoETeG etaving yd ,obem evew edqnedda- (m- etedaw Wowhoed Jaaty ed? antbulont anelo oftioe'’ ot To emoa. eos -Etodsw ental off. eSatloreo Asdou bne ,emadelA ,eneletuol -at ,efsos Liam wid at ifeei! beteiidajas jon ead tedayo . esenadab od ig weqet ders eonebive .om co! ered? bap e2totay Wy) baa ok ' *8YO esenaget oft citiw beietooess eetmene tsdto Yo lone eJeno9 Bldt of dnguoid etew . eb “Mgleror tedio to s¢enaqel jneic of etynedde evount? bra olineliA efi to aeete fatenoo od at etoseyo to # “76% Io gaomietidnies elt at Jfueot yLflantaeve yen tetas wat edd To dmenedelqelh ould dae atotew overt wt dertre OF BOdMeuUpORMOD avoltes edt to wolv AT »tevero mrote v sgubortta! Orasadesd a at dfuzer yan taco yateubat “tosayens Betniorge od epriinmos @ tadtt seogomq ew ,neloece ofsoxe to mor OROgOtR Seddavt of .eelsna avolasy mont moldoag edt -ybudi - to feet! soale motiatsoasdé aot terelifirods Lanois | od -, Bae ofinalsA Ila ed etoftiqobs sAt bebvommoser nafvad v % tae "yee Ges Ad Gulf States, an uniform legislation for the control of the im- portation and planting of non indigenous shellfish in the waters under their respective jurisdiction. Respectfully submitted, James N. McConnell, Member David H. Wallace, Member Paul S. Galtsoff, Chairman vi £ ed? to foxrtnos oteaw ont nt pe aatnitede am “gon to ¥ i} . ; sMpnoldetaer aut 8 aN 8029 dade citantonses ae tedmeu ,llomnovet wi semat ‘ cantian) ,iioesiay .c Inst iv ies: * ae "On the functions of the mantle, gills, and palps in feeding of the oyster with especial reference to their operation in turbid waters." Thurlow C. Nelson, Ph.D., D.Sc., Professor of Zoology, Rutgers University. Biologist, New Jersey Division of Shellfisheries, State Dept. of Con- servation and Economic Development. A problem which has interested both the practical oyster grower and the scientist for many years is whether oysters are able to feed in muddy waters or in the presence of high con- centrations of food organisms. Time will not permit a review of the conclusions presented during the past 34 years since the famous controversy between the late Doctors Grave and Kel- logge in 1916. From the position taken by these two outstanding zoolo- gists one is forced to conclude that oysters will starve to death in water heavily charged with food organisms or with dirt. In 1921, however, 1 showed that oysters would continue to feed in water bearing as high as 0.4 gram, dry weight, of suspended matter per liter, which over most of the oyster's range in America would be classed as muddy water. In 1925 I published a summary of our observations on feeding of the oys- ter under natural conditions to date in which it is concluded: "4, The rate of filtration of water during any given period of time, as deduced by the rapidity and extent of ejections of accumulated sediment from the mantle cavity, may vary widely independently of the temperature and the turbidity of the water." "5. Oysters do not necessarily feed at all times when wa- ter containing food particles is passing over the gills. Rela- tively little food is taken on the ebb tide and during the lat- ter part of the night and early morning.” The issue was again brought to the fore in 1947 by the work of Loosanoff and Engle who in supporting the conclusions of Kellogg '15 and '16 showed the harmful effects of heavy con- centrations of food organisms. Since these authors further proved that clear filtrates from the cultures of such food organisms likewise caused reduction or stoppage of feeding, it is highly probable that their results were due to excre- tions from these food organisms which the oysters found objec- tionable. The role of such excretions of "external metabolites" in the economy of the sea has been ably dealt with by Lucas, C. E. '47. The difficulties experienced in growing and fatten- ing oysters in Great South Bay in recent years may well be due to similar excretions by the algal "small form" which occurs there at times so abundantly. af ogfen See ekee ot sonene' ter ri “eited aw: bi 4g +98 F gotta 4H nL ott #0 wolasl? oUtionvevtal avoenieh proofooS to tebsetor? to noheivid poorest wet ,delnolokd “naD to siqed evade ,eoivetehiifed2 -tromyolovedi ofmtortook Hrs aoljawvies ,olinen eft lo eeotdanet m" Bis. ee diiv tegoyo old to saa id Me ih nokistego tied . a Medeye Esotsonng ont ddod bodeorodnt. aor dofdw moidoug oe ome ateteato wordedw az auney ynom tol teldnefos odd Bas ft 20 ag 4-2eo esneeedg oft mi to esedew ybben al Deet oF” wolvex 2 tinser dom Iifw omit ane largso boot to smokin eonta eise Sane ects Subiuh betacseiq esoleslonoo 1 efel tas svat axpio etel als noowted Weneventase ee “ofoos pebaela. see evedt yd modad aolttieod edd moa of ovusda Iifw wietero tadd ebulonoo 09 beotct af ene, divin +o aneinente boot odtw hegtato yliveod cedaw f * onnticed bisow exogayo data bewots I ,.tevewod , (SCL az © to ,ddighow Zeb. mom d,C ac datd oe aniaeed totaw ‘at Oe etroiayo oft to gear tevo doldw .set RM 16q aetdam Bebom EOSOL ml .medew ySbuo ce Decueld od Bluow sotaemd at “eyo edt to. sibeot no anotieviesdo 40 Yo ytaomue 4 Sede big remy (ol dotsiw at eiob of snotdhbuco Lesson % Botateg yas rte, tstow lo motjexsitt to efee 30 patigy More G Pnelxe Hae ziihtaet ed? yd beouheb eA oe yiehlw vay Yam qyiivao ofinen edd mort toenthos Bedaimm ",toIne oad Xo wtb ids at? boa sivtategaed ed? te iat at “se gedw somtit rth an beet yiinasesosn tom ob otesey0 een ~areH .affks edt “evo onieesc ct sefoligaq boot an nisaned egal mit aniaes Ban eb? dde edt so nedead ef boot efedit yee : Megateron qineo ong ddgia edt Lo dae ait yd Teer et ortot esd od. ddguowd . + ‘ORw reed antatonflomes end anlinoaqus ai odw olanS Bas Plenasool onde yveed to etoetio LW lmted orld Lowore OL! ban aL" 7 ports aird Bacitve epadd oontd .emelnegte boot Yo anoky, ay Loot dows To) eonvtivo oft mort aceietd[?) aaelo dads Dawe ganiseed to dgeqdote. to noliouber beevao salwoddt aie. ‘meee of bac eaioy advan: «lets Jgadd eidodorg ylupid & ps bree) ‘ered ayo eid doldw ooaknagye boot @tedd, mogk heodt odetem Lanveatne" to anolsoroms done lo efot mci wo ldap .«l «4fetaalqenet? od 5 pis to eerie a” eqad oft to edee esaob edi gn lventny woue alas 16 Yeosk§ tao fonds adhe eyab ned abative 2 ant etedi. 00" ineost he ont al didldxe aa al qwoda Pedenteifese ete atetero xc urce edd to amos tan’ yvaeer os. ‘othe aofdw exorid Lexenoyn al isdt awolfot #2 “edoddnlen 4 ted tien ietiew eno tL .s0%m Jest od Bodiva toed ofeste te Bs “odd | Bbavory.yaldise edd mo bestwooe ead, cold: ile ¢ yan doldw .fasrmoiwtvae jets of betine deed exods “om 4 "galwons extd to uneaaanie enolsvibaco edd mot?) tnetoe Thies beiuian ete aredeyo Tyo" overly / fom gicod # a! ons ,nbr0907 tested bae oro geet ASP stead stegifaove! og nil helieo taldnelos yrov «heed rite, of Bestel meed aad utotayo Yo ytliodnom to eer ‘So YuoFetd auotvetr eid es an? oc a? o1ps modt etlup.aag pie cogs y Lotoe YaebnaqeS sf of ~hentiegios sh nretey wapheaiain doa of ,ceteslooese cli¢ Lo boa tesvaniq ent te we Peeitd basiet oved I sacey OF .omos to eonefteaae ye af jee # ~epitonen Door dify atevrosdo neal one etewor 036 ) aevo oval T dsicw epetiit om. ot -tuo Setatog plage oat Hood nol booy e qeoil :e1 [diifotnl 20m. ems ao hetomert sue | eno Bqesx oletqss $a odd Eteve Yad? sor Dae dneiq awo Me tees se .20 arid gid te nottiay veton dtlw eiab of qu Brame Sime Le yo tqext anol Hheliaseb bood ted aeterd efdingog tt To ontn Boa 8 swooed cocoa hluog cvtevgeedo Lotetas. fe : ‘bs Pose calcu dehaule Sem Woy med’ moms ateliaoter edt od: aeke, 200% OR Bpaidd. cotw 80 ae _tie® egref we etealg tenath tonne e 20825 yitbidand a. “exeid eqeeih topt vf L523 ntl boterdiiss a a0. berewol ,ob Lf}w! gait end den: tod ded. «tail end no diqgeh edd. efon- ‘nodd a “dnlaq hue .geques yo moat deods to efoto font @ nm woes tgtew 2 aeten? ,odtdv bas deed Lo. siostiagp tanned most If towel “sth eveda Jost be Cahiadealaucansi) baiaa | the sunny side of the boat, note the depth at which it dis- appears. Record this together with the hour, clearness of the sky, roughness of the water. Collect salinity samples especially at high and at low water and during times of excessive dry or wet weather, Crdi- nary pop bottles can be used if fitted with good tight stoppers and delivered promptly for analysis. Most of the maritime states now have marine laboratories the staffs of which will be glad to assist you. Remember, you are many, you are out on the grounds at all seasons and in all weathers. You are in 2 posi- tion to obtain much information of value to your scientific friends as well as to yourself. (3). Keep accurate records of the volume of shucked oysters obtained from the various beds from year to year. Keep track of unusual storms and note whether volume falls off there- after. Be sure to take salinity samples as soon as possible after such storms, for frequently they are accompanied by greater ingress of sea water which shrinks the oysters through withdrawal of water from their meats. If you are using some muddy bottoms, watch carefully for signs of mudding of the oysters and determine the sdvisable duration of time to leave them on such bottoms. Cften early marked improvement of oys- ters from superior food conditions here may be obliterated through subsequent interference with feeding as the oysters sink into the mud. (4). Finally, muddy water in itself is usually not harm- ful to oysters provided it does not deposit mud in too larse amounts or too rapidly about the oysters. ‘When md rises above the bills of the oysters in such quantities as to inter- fere with feeding, or when by cutting off oxygen it produces large amounts of hydrogen sulphide, oysters may be suffocated, as in the severe Polydora or mudworm invasion of Maurice River Cove in the mid thirties. hud often contains much that is of value to the oyster. When mixed with sand it prevents it from shifting, binding it together to form some of our best oyster bottoms. Chemical and biological chanses going on in mud, similar in many ways to those in the soil of a good farm, produce much of the food responsible for some of our oysters of most distinctive flavor. Dr. Caswell Grave '12 in his "Manual of Oyster Culture in Maryland," a work which deserves reading and rereading by every research worker on oysters, was one of the first to emphasize the importance of the bottom to the food of oysters. Twenty- four pages of this excellent report are devoted to the food of the oyster and the factors “avoring its increase or decrease, with emphasis upon the bottom. He attributes the superior fla- vor of Lynn Haven oysters to the nature of its muddy bottom. In 1921 we reemphasized the importance of bottom diatoms to i ets. dotiw 9s digeb etd ton. dood add: 20 9 t “to sarnand vane ote dtiw aoddonot eld? bc stedaw odd To sat ‘wot de bas dgid te eilaloedes selqraes causes spots ehbt9 .serdeev tow. to yah evicaeoxe to nomid gatayb f aveqqote fdgti boos dilw Bessit If beau od aso celitod & sotate omittaam edi to deol .eteyfsns tot yLiqmotg tenor lal bells ed [ftv dotdw io ctinie odd seltotetodal snisem vi yes edd no duc ote woy ,{nam ete Boy ,tedMere! §.NOY-s ~leoq 2 af etm soY s2terdaew Ife hl bas sncesee ifs joe gbthdnefoe aoy of ovley to moftdmtotat dom aleddo ¢ «tfLeewvoy of en Lflow ta: belowie to emufov ed? to ebrceea edatoom qeed ie “qeel .te0ey of taey movi cbed evolaay att ott bealaido a4 “oted? Ti effet emufov zsitedw edon bna emioda Isyeunts To) Gidletog ea noose se selquse ytiniles wlad of vies beflaeqmooos eis yout yLineupetl tol ,emtois degee Mayvoms eteteyo od exmitie doldw tevaw Hoe to. peli ce emes nalew e1e@ voy tI .ateen tledd movi tstew lo faweq end %o gatbhbir: to angie iwi ylivtereo dotar, ,emoriony eveel o? omid to molsenrub ofdaelvha ed? onlertodeb Sar ae “879 20 Yoovevotqa! bexaem céaee nett sanotitod dove ma bojates Lido od yar oied enoltibaes bool tolssque samme evelsyo edt as paliest : igiw 99% wore tted M2 tneupesdes dp bum end ode 4 sHted ton yffeveu af Yiecd! at totaw cbbym ,ylfonti of ry enaet ood af bu: sleoceb jon seob Jf beblvoiw si9eseyo Ge eeeta Sum got) .eteiayo oft tuoda yibtqa1 90% 10 Bm sesnt of so veld iinaue dove af atedero odd to elild « Geeubonm si nenyxo Tie gnivdwo yd nedv 10 yalboot ad? Petaootivs ed yam exotero ,ebidqive nenoth “a to edanons: tevifl eolwel to acleeval miovbem 20 atoby Lot exover odie sols alas bin edd a 7 pintaes @id od oylov io at ted dou antedaoco netto Bat i gmibatd wyaidtise mov 31 etqeverq a1 buse diiw bext " * eteedo. samotdod tejeyo teed ao Lo esot wx0l of Ff Ade eyew qaem at tlintc ,Oum ai mo gokon eeonrtarts {sotnolokd boaot eid to down eouborg wii2t S003 @ to floes aid al ecadd stovel?t ovidontdelb soon ic axejayo two Yo. enoe i101 efdis mf enodsi tede~9 Lo [euned" eld at BE! evesd {Leoward ae yreve yd golisorst bie galbse: cevreesS doliw wrow ° * baal 1 esisadaqne of dexft odd lo eao vay ,.etedeyo no casnee doteesee wet new e@tedeyo to boot ort o¢ motdod edd Te onal sogntF to boot eff of betcveh ox s100 9 tanelLeoxe eld? Yo eb ee eezeteeb 10 seeotont est nittovs erxogoa? efi Bae sedeyo 6 -al soiltequa od esiuditasia of ,moddod at? noqu-els ne aed etodtod ybbre; 2d? lo ervisa end oF atetayo aevall nayt. 20. od amodath motiad to ones soqme eid Hees Ken GEINt otis .y the food of the oyster estimating as many as 52 million diatoms on the shells of a single oyster 4 x 3 inches in size. In 1947 we again stressed the importance of the bottom showing the heavy films of diatoms occurring on the Cape May flats. The great majority of studies carried on in oyster bear- ing areas have dealt with the water flowing over the beds, These studies are important, and we could ill afford any de- crease in their number. Rather do we need considerably more of such investigations. Of equal importance, however, are companion studies of the bottom, of the contributions to it from the land, from the sea and from the animals and plants which live thereon. Dr. ZoBell in his most valuable book on "Marine Microbiology," 1946, devotes two of the 18 chapters to bottom deposits and to the activities of the microorganisms contained therein, It is a splendid beginning, but we need far more research in this field. In our knowledge of this all important problem we are about where the farmer was a half cen- tury ago, but as he and the world at large have reaped vast benefits from the researches in soil science, so may you and we gain much in the future as we learn more about the relation of the oyster to the grounds on which it lies. ‘bei ‘wedcieae a ee ay of tt f ior by aectont’ £ i | ~ erld natwode god tod ‘ery "he ovrunds eh leit bat ana ena so Bal amweeo | iil wtsod tedeye a me Bela’ eolbude Yo) strobe ssbed ont a600. gui wolt tetaw ‘ert? tg #8. Bhs Pi iL vista sv = we ednelg bos efentas oda ae’ bor Bes a “movk ‘bit Ho aAood eideviey Jeom aid at {fefos +t eresqedo OL exit to. ow? eetoveb geet Ps sarod enetne@atoordic edi to selilvidosm edd at bas etleogeD Beer ew Jud paLaained Hbibuetqe a et tI ‘enteted? Efe aint to enbelwor: myo al eblett afd? at corset aed Ifet 5 ase tects? ofd esedw duods ets ew mofo jeay beqaes evar opted ja Bidow oid Bae ot es sd Boe wer Yet oc .voneltos LLoe al eetoweest add. Biss eal edd fuoda etom aunen ow no eatutel edt mt do etoll sf doldw ao ebugoty edz o2 ted References Cited Chestnut, A. F. (Unpublished) "Studies on the digestive processes in Cstrea virginica." Thesis submitted to the Graduate Faculty of Rutgers University in partial fulfillment of the requirements for the degree of Doctor of Philosophy. pp. 89 (typewritten), 16 © figs. Rutgers University Library, New Brunswick, N. die Grave, C. 1912, “A manual of oyster culture in Maryland," Fourth Report of Board of Shellfish Commissioners of Mary- land, 1916, "The process of feeding in the oyster." Science 44: 178-181. Kellogg, J. Le 1915. "Ciliary mechanisms of lamellibranchs with descrip- tions of anatomy." Journal of Morphology 26: 625= 701. 1916. “Opinions on some ciliary activities." Science 44: 852-855, Loosanoff, V. L. and J. B. Engle. 1947, "Effect of different concentrations of microorgan- isms on the feeding of oysters." Fishery Bulletin 42, U. S. Fish and Wildlife Service. 51: 51-57. Lucas, C. E. 1947. "The ecological effects of external metabolites." Biological Reviews 22: 270-295. (Great Britain) Nelson, T. Ce 1921. Report of the Dept. of Biology, N. J. Agr. Expt. Sta. for 1920: 319-549, 5 pl. 1923, “On the feeding habits of oysters." Proc. Soc, Experimental Biology and Medicine 21: 90-91. 1923. “The mechanism of feeding in the oyster." Proce Soc. Experimental Biology and Medicine 21: 166-168, 1938. “The feeding mechanism of the oystere 1. On the pallium and the branchial chambers of Ostrea vir- ginica, Cedulis, and O. angulata, with comparisons with other species of the genus." Journal of Mor: h- ology 65: 1-61, 21 figs. easoon evideeald etd ao egtbuta Sedétt i ed? of Host hudye afeced? " 24 Ne ae aee ai ydlevevinl ete son to viivost oy Ae ii pod ‘edd tat etremertupet ett. to, oT siterias ji KC ners Lowoqyd) 28 wox etdqosoltdt to toso0T | | glodwenwsa wet .~iand it XFEnay av ered uit or cdeavot ".Snefyiall at ead luo neieyo 0 Ieunem ao “asa te wkenat esfeued sorts tone to ag to po * @onelo® "“.xodeyo add at aatbest to eaes0% eit” elf leHVE oo] Unghgeet djiw edoneatifemal to smesaedoen pansttee ua 98 8 2s ‘YaeLorigntont to feniot. "._motaae Io enokd et poneios ",nettiviteos yitalite emer ao onolatao” " 25d 828-888: 585. ; pelget «Gh 4b Bae ot oV ; ieaseo-tote to eolsatdneonoo g¢neteliih to toettZ” Giteline yisistt “,oveteyo 10 guibeel ons so amet evael& £2 ,ootvree erlipitw baa deft «2 .U ,&d . Pe * eoti Lodad om fearedxe to etoette Leotgzolooe eT" ~ .Vi » (ated 246 dae) .G@S-O0TS 8S ewelvor faotgofota ie , ed .D ) wiGe® .tyA .t eakene to eae odd ‘to sroget «LS. \ «fc & ,@bb-OL6 sOS0L tot sata 9902 .00%% "Letodexe rt edided anfbost edd m0” of@-08 :f£2 ontoltbo bus yaofold fadnembteqna — gpotd "Vaedeyo ert? nt gatbeot to meinatoem eft? “qB8EOAL 218 ontotde ban vaolotd fataentreqal «998 Ag AO LE stedeyo odd 20 matnadodie'ga bug? edit” - ad, paeise 20 exednedo Ietdonatd edt bar mob leg o GAGA raiaeD cht iw pataiuane « «2 Dee . wl: om on oneetmald ens al¢ to seloode weado & ae Va ee et 388 sae 1 tar Nelson, T. C, 1947, Yonge, C. M. 19266 1936, "Some contributions from the land in determining conditions of life in the sea." Ecological Mono- graphs. 17: 3557-346, 7 figs. "Structure and physiology of feeding and digestion in Ostrea edulis." Journal Marine Biological Asso- ciation of the United Kingdom. 14: 295-386, 42 figs. "The evolution of the swimming habit in the lamelli- branchia.": Memoirs of the Museum of Natural History of Belgium, 2nd Series, Vol. 5. Paul Pelseneer Memorial Volume: 177-100, 10 figs. 10 basen ai nt “Broth inofgosood ' ditsbauen bre pared Yo: raofoteyia bane oud “ea ofeih ealaat Lannuyol eO0E-O88 :bt amobye tu betin “ead ote aninmiws edd to withgeete ean soteat Prete ‘to meetul ort to ettomel “setdonssd — tosnoetet ced.) ot afov goelted Sas: qiwty Leu to. etytt OL OOLety tomo rattonell Studies on the digestive system of the oyster. A. F. Chestnut Institute of Fisheries Research University of North Carolina Morehead City, North Carolina Many papers presented at the annual National Shellfish- eries Association during the 1930's were on the-role of oysters in human nutrition. These papers by Drs. Pease, Remington, Coulson, “hipple and others discussed vitamin values, iodine content, oysters and anemia and nutritional values. One result of these studies was applied in advertising to promote greater sales of oysters. Since 1942 a number of papers have been presented at the annual meetings on the basic problem of the oysters' nutrition or "what do oysters eat?". Oyster growers and shucking house operators are well aware of the fluctuations that occur in a single season and from year to year in the yield of oyster meats per bushel measure. Some years the yield from the same locality may be as low as 4 pints of meats per bushel and in other seasons the yield may be as high as 9 or 10 pints per bushel. During the past fifty years many scientific studies in this country and abroad have shown that the chemical and phy- Sical environment closely associated with the food or plankton in the water may exert a great influence on the condition and yield of meats. The literature is too voluminous to review in this brief discussion but various theories have resulted from the studies on the nature of the food of oysters and other lamellibranchs. Some investigators have concluded that oysters feed exclusively on plant-like organisms; others be- lieve that animal forms are utilized as readily as plant forms; and still others maintain that living forms play a minor role in contributing to the actual food supply. The original intent of this study was to follow the diges- tion of various foodstuffs by the oyster and thus determine the process involved in increasing the yield of meat. In the course of study it was found that descriptions of the internal anatomy of Ostrea virginica were lacking and needed to under- stand the processes of feeding. The internal anatomy was found to differ from that described for the European oyster (Ostrea edulis) by Yonge (1926), for the Portuguese oyster (Ostrea angulata) by Leenhardt (19265) and for the Bombay oyster (Ostrea cucullata) by Awati (1931). This is not surprising for other investigators have shown differences in the gross anatomy in the gills and other structures, in reproduction and in physio- logy between various species. (Orton, 1928, Elsey 1935, Nelson 1938, Galtsoff 1932). th Samed nodD. * e A seisenen eeicedalt 4c hicesasat’ anifortao rdtod Bo eolesevia’ - win 8 bind au? to baedenoy efeltifed2 Laaolsatt. leuane etd de bevdeney, ‘eterod areteyo ta sfot'edt no etew e'OS@Ol add yaleub coliatoor anod gr Lief gonaod .end yd ateqaq seett cold batons BAEDOL yt soulhy almediv dessvoat® etatto huis elqgia tfiaes on .seciov Lsnoltfadyn hae stmoena brie ete: e *otaetn otomosg of gnislinevhe af Beliqge saw telbude. en ested eyo: oY: nolitatina taxeyeyo etd to mefdorwq slesd et? fo cgnlibed eenot onblomie bas eroworn sedeyO ."Ptao axetego Ob a2 a2 tuooo dort snoliantonl] ed? to evawa Ifow eve tetezo to bfely edd al wey 3? 18 oY mont five nosaee emse oid mort Diely odd. ewey emoe ,ercesom Lodead ge ni Dna Ledend toq ejaem to stalg & as wot ca ed yang toq asaiq Of 40 @ en datd sa ed yom blely odd ano ea! ony dn beinesetq need eved etenaq to tedmum ae Si mi selhiois ofthinetog yaam exeey yITlt deaq ed? pale “yiq bue Isotmedo edt dadd. swore eved beoaws Dew yu rm movunetq xo hoot edt dtiw betaloocan ylerofo taomaoaky bas aolitSnoo ait mo eomeulLtal Seer & diexe Yam Ode watver of ewontmwfoy oot at emiaterli oAT ~edaon Hheifyest evead seltoedd avolaay ted aoteswoelS tok a ‘bag ateieyo to bool edd to stsdan ol? cio getbuga wf tend Dbebvlones evad evotenlideaval emote .eadoneadl {fe “od weteijo ysmetnanro elif-tnaly ao yloviantone boot | pamrot gnalq sa yfibeer as beslitiu exa enol Lemtas 8 akon tonin 8 yelo emtot patvil dadd alsitatem atedio. «Yfaque boot {arto od oF gattadl ra i, ae iF w@eptbh en? wolfot o¢ saw yhude sind to tnasat faniotao 4 ‘i enlmiedeb suit Dos toteyo edd Yd elivdeboot evoltay edd mI .dsen io Bfoty ond yatoseront at bevfoval ee fanreinl oft to anoltqltoseb Jedd Bawot saw df ybuds to AGE wteiug ot Debeen bias ga hloe f eter BO assed % i iwel sew ymotene Leaietal ed? ~aakbes oO seeeepatg es: bh Bettis0) teteyo neegot eft tot hediaeeeb dads mout, tee Re Betico) teteyo exowyutrol eft tot ,( ase). satoY xd. ‘tedeyo yadmud axl “ot baa (ages): -SDradaoed vw f TO) ot ert @ squire ton al att. ALSOE)) Siere ya ity “nt reo facie seotn odd mt soonetottib awode oved Pesta mOteeiy mt Deo pi on in wqeu af ,sermtoutie teddo Bae of} Moston ~G8C0l yeels ,8ses e099) snoetoods eet SOM a a ol Gees Toes, Description of Stomach: The sorting mechanism of the gills and palps has been de- scribed in the previous paper by Prof. Thurlow C. Nelson. The various food and other materials passing over the gills and palps enter the mouth and pass to the stomach through a rela- tively short oesophagus. At first glance the stomach appears to be without definite shape but gelatin casts show that sev- eral definite ridges are present. Seven openings are found leading into or from the stomach lumen. At the anterior end of the stomach is the opening of the ocesophagus and at the pos- terior end is the combined opening of the style sac and intest- ine. There are four openings connecting the stomach with the digestive diverticula, two in the antero-ventral region, one in the posterior half of the stomach on the lower left wall and the other nearly opposite on the lower right wall. At the anterior lower left corner of the stomach is the opening lead- ing to the food sorting caecum. The most conspicuous structure is the ridge or typhlosole along the floor of the stomach. The anterior end of the typhlo- sole passes into the food sorting caecum and the posterior end turns dorsally to enter the intestine. On the right wall are three ridges lying in a dorso-ventral position. These ridges end slightly below the mid-section of the right wall at a long- itudinal ridge which overhangs the posterior right duct, and continues anterior to form a transverse ridge under the oeso- phagus. On the left wall is one large convoluted ridge extend- ing from the roof of the stomach ventral to the mid-section of the left wall. The food sorting caecum is an outpocketing of the stomach originating at the left anterior portion of the stomach and ex- tends posteriorly between the mantle and stomach, then curves to the right under the floor of the stomach and continues in a coiled fashion to end under the stomach after describing one and one-quarter turns. An irregular, two-lobed translucent gastric shield is lo- cated along the dorsal portion of the left wall, extending to the dorsal surface of the stomach. In animals which have been actively pumping water, a crystalline style extends from the opening of the style sac and projects across the stomach to bear against the gastric shield. Course of Ciliary Paths in the Stomach: The stomach was laid open by dorsal, ventral and lateral cuts to determine the paths followed by the particles entering the stomach. Mixtures of carmine and various grades of car- borundum were used for inert materials and suspensions of algal cells (Navicula, Platymonas, Chlorella, zoospores of Ulva), and starch grains were used as food material, 12 ~ob need enc yaa na efits edt to jig eat ,moaled .o woltudT . tort yd weqeq auotve My eg bre 2iiiy eit tevo antsesq: Seu lnetan ted to } ~elox s duvontd dosmoia efd of @eaa San désonm edd mode etsedas Sonnets ony yr ry fowl FA 6B oeeo tte ae} “veo jodg wore aiese aivaley. tad eqare siintieh Jaom Burt 3 brvoi ets egatmego neveS .Inesetq ets Bendix aff ar" Sere tolteine edt. 3A tenant desmots edd mort 10.0 eeod ol? ja bas exmedgosvo etd To anineqo eft ef dose eseoint bas ose efyde ect to gnineqo healdmes add eb: ae eit diiw cdoenmote eid nxldoeanoo egnineqo uot eas . um eo ,folsen I[eginev-orsica odd al owd ~eatoolinevia: oY Ifiew Stel dewol ei mo doemode eft to tar tol resect eid 34 .silew ddats: tevol edd mo stleogao ylasen teddou ebrel yeimeqo edd ef doanote afd Yo tentoa Jtef ee aimwoeno 3nitica sks eforoldqyt ao onfix eid sf equdswide exovetqencs shoul ~ofsqys eft to Bie voltoins edT .doamots add te OO LT By Sane toltedgeoq edd fre museno gatdioe boot etd. otal a eta Liay dents od 19 .oniteodal ons tetas of yiise beybit eeed'? .doltivod fatinevecetob a al anizt soghs egnot s ta Liew digits eid to nottootebie add wofed ita bas ,toub ddgl« tolisiteor eld ennanrovoe dotiw | “9200 edd mab ono!« vetevanetd a stel of to itedae siaetxe enbls betwfovace ojtel emo ef Ifew tteL edd AQ to nolseor«bin edt of L[attney doamode eds to loor eddie doamose etd Yo gal torloog +10 as af meoess arlitce ‘poeta “xe Sng doeamot)e ait ‘Iso aolttog solvetas tisl edt te aay esviwd sedd qdoamots bur ofinem ed¢ neowted- yinoizeta } ai sotmitaos bar soonota att 40. moof? eft sehan da | 90 aniditoeeb tedte doanose eft aebay bae of mold arts sodtsy -“Of ef Bhafcds oltieag snsonulenatd bedol-ow!d ,taieges i. od seibseixe .ifsw Jiel ed¢ to moltaod feared edd ne geod aver doidw sleminc ai ,oammde edt lo eonita Lem add mawt ehoedxe efyie snliisteyas @ ,~tedew paiqueg ge o3 doamote ald grows atostoug bas ose ef¢ss add. A. he HhLelte ofadaay ont den ‘dogmas é. ei) as AGEN aed Leteint dae tela yfnerab xd “nego bhal eae Hoamode wilteioe esloliang ed? yd bewollo? ending odd saimiote | wtao to acbaig avotiey ine eninaso To sotwixit | ytla taata to onolnaeqaue bas elatseotam tron! yo? bese etow haa haven io setoqeoos ,e{foroldd ,sanonytald oiuely . eloiteten: ‘boot ad mene, ae : ae Particles that enter the mouth are carried posteriorly along the oesophagus. At the inner edge of the oesophagus, near the stomach, the ciliary beat is changed and the particles are carried toward the left and come under the influence of the cilia of the large convoluted ridge of the left wall which beat dorsally toward the gastric shield. Heavy particles that may pass directly into the stomach from the oesophagus come under the influence of the cilia of the transverse ridge under the oesophagus end are carried toward the right wall where the cil- iary beat is toward the gastric shield. In the posterior half of the stomach the ciliary beat is posterior and ventrad so that particles are carried in two di- rections, toward the posterior right duct of the digestive di- verticula or end up in the ventral groove along the floor of the stomach and are carried into the intestine. The ciliary beat on the typhlosole or ridge on the floor of the stomach is anterior, carrying particles into the food sorting caecum. Along the right side of the ridge is a deep groove or furrow with powerful ciliary beat toward the poster- ior, carrying particles from the stomach into the intestine. Food is consolidated in the intestine and carried along to the rectum and anus. Heavy particles that enter the stomach cause much mucous to. be secreted and strings are formed that are generally swept across the weaker cillary paths by the beat of the stronger tracts. Perhaps the most powerful ciliary beat is that of the ventral groove. Another powerful force in changing the normal course that particles may follow is the crystalline style which twirls around as it projects across the stomach. Mucous strings are wound about the head of the style and particles are di- verted from their normal course. The role of phagocytes in feeding: Throughout the oyster, in the tissues, blood vessels, in the lumen of the stomach and intestine, on the gills and in the mucous masses are found numerous wandering phagocytic cells. The ability of these cells to ingest and digest various food- stuffs has been shown by Yonge (1926) in Ostrea edulis, and were investigated in these studies. Oysters were fed starch grains, algal cells and yeast cells, in vivo, and stomach con- tents were examined at hourly intervals to determine how rapidly the materials were ingested. iithin an hour diatoms and starch grains were found engulfed and plasmolysis of algal cells oc- curred within two hours. Studies in vitro showed that ingestion may occur within 50 to 45 minutes. Complete disintegration of algal cells takes place within two and three hours. Empty diatom tests and reddish- brown granules, presumably the undigested residues, were fre- quently seen being egested by the phagocytic cells. Yeast cells 13 Vaolredton betrtes ose dtuom edd pitne sends ee Vo v4. 6 BNDaNIS - Rettebieg edt bne besaete a: tned ytmtite edd odes ad to sonenltat ord teoae enop hie dtef edd braw © epbi+ betufovacs it blll , Yee tadd selotinag yveeli .bfetde olttenn end bee febaws omes eunatiqoseo end Mort dosnote edd otnt ¥ oid tebau exybia eevevenead odd 10 BILlo edd Yo Bo wd “fifo oft eterw flaw Jdgie efd Huevos belwane oy Das pt ‘Sloide ofvteen ad? buawot el ! of dood ytefllo edt rommote edd Yo tfad a0ledeoq ed? | | “iD owd af belriso ea eelsisiasg dant on Sstinev baa qe mi vib evideenth od# Yo toub idnt? tolteteoe edt Brawat |) To tool) edd anols eveo atinev odd al qu bne 10 8) eonltesint edt ofa} Delwtas saa baa dg ore TOOLT oid mo enbt+ ro eloveoldqys add mo saed bye pd 3 Soot od ofnt selfotiasg antertes «toltetas st doamoge Geel a ef obits ed 10 able Srinte oft nnols sMUOeHD “telsoq sid Deewos Jaod ytsatito ivtrenoq dile worrmt ¢ sOdlJsostat edd otn! doamote oli mow? eslolia, aa Ont oJ gnofe Hetiias baa emidceyal eit a! bedabifoancal : eure BwooLt don ecugo doamote ei? te¢no tery befottiise yy dqewe Yileteneg eta tat? benrol ote aunttie San hetewse Segnowss ed? to daed ads “9 ediag ytellio rslaow she ony Lo tady ef taed Ytelllo Lotsewon deom eds sqatqed 1 iy famton etd gntnasde al oqo fgitevog tedton, ,evooaml is Motiv olvie ealileteyio aff al wolfot Yon solotiqay sade 830 to avoow .toamote ead S80%O8 Gtoelor st! ee Bayes - wlb one eelotiaed bas ofgys e923 to baod end Jdyode bine eSettvoo Larmron thede most eg we, i 2 Beet at sotvoonada ie « af ,efeerev Boofd efoueeks ett at yxeteyo wid Iron gsromt ony ol bow ellis oft no Aovete Det savew Srecey/y ,eelbeda esaatd ni besantsaay "0809 Moamote bre yoviv at ,Sfleo geaey fae elLfoo egies em, — UEbhdes wort entradas od afevietm! Ylauer to bealmexe etew 2g Hotate San omotath «work mo sate bt ae “00 alles Lenina to ‘es ehetcenal eter elolredan: steylomanle bag bei Lenn Savot erew wi . eCivad ows widd iw & Middlw wyso90 yan Moljaonal todd Hewode ongiv mt aolbusé | Beles efleo Lage to Holsimusedalele eteLawot seodentn Bf lethber bas etaed Hovelh yiqus ..wwel eetdd Sua owe atigin: ) 7erl etew ,aetdtse hotsonlhay edgy Viderueoiq eelunnty eifeo taneX yeffas oldyoonaiq oft vo beteene anted aves ef stained with Congo red showed a color change from red to purple indicating an increase in acidity within the cells. India ink, carmine and carbon particles were readily ingested and within an hour after ingestion the particles were passed out. Injections of food particles under the surface epithelium resulted in concentrations of phagocytes in the immediate area with many of the particles being ingested. Some particles were eventually seen passed out in the fecal strings. Digestive enzymes: Quantitative and qualitative studies were made of the hy- drolytic enzymes in various extracts. The extracts of the cry- stalline style contained strong amylytic enzymes that readily reduce starch to sugars. Lipolytic and proteolytic enzymes were found in the extracts of the digestice diverticula and in the mucous masses containing phagocytes. The stomach contents were found to contain only an amylytic activity. Summary: In the process of feeding a rigorous selection of parti- cles occurs on the gills and palps before they reach the mouth. Within the stomach an additional sorting may take place by cil- lary action, mucous secretion and within the food sorting caecum. In the living animal the paths that particles follow may vary considerably depending upon a number of variable factors. The amount of inert particles, concentration of food organisms, rate of mucous secretion and the influence of the crystalline style all have an effect upon course particles will follow. These studies described are far from complete, but they do suggest that the food of such forms as oysters med not be limited to plant or animal forms exclusively. Any organism, whether plant or animal or a constituent part, that is capable of being ingested and digested would be of importance in con- tributing to the food supply. 14 rye?) Ree | eee a ve Aes ) ‘ | : = ; .% : Ot Bot mort epmado teLoo 2 Dewnde bet ope etal asthal .eflfes ott middie Y3lbios al sarexon middiv bas beteonal ¢ftboe: sisw keto dteq nox +30 Desens ctew eselotiaag aid aolizenns _fulfedsiqe eortive efi sebav selolixzeq Bool to enolJsoot Sern osathem: oft at eetyoogarig to eno! tani neonos al-{ ““@tew seloliasg omoe lateral ates solsliaeg el? to etuniasge isos? e353 at duo beseaq nooe y fF 3 fet - “Ti of) tc eben stew eetbude ovisetlfeup baa evista ies “E30 ais Io stoantixe eiT .adoetixns avoleay at sonegsae ~ QitSset jad? comysrre oftyfyme grote bealetaos e tte. Seeysae oliyloeiotq Saez Shiylogil .etnee of dos Mi Bac alwolsadevib ooltsenkd wis lo sgoaatxe eg at ; Sinednoo doamcin oiT s,sedyodperdty antintadnos sesead of eliivisos olticiyms na yfino ntasace of Sam Cas “E3%ec to noltosles suOToNlt @ nalbest to ssescts oft es eflduom ati? tonet red? etoted eqing Dar eifftn o'd a0 ans sifo qd eoaiq wisi yan aaltwe Leaoldifbs an ‘sanode ete emyoeso aiti-tos boot sid atdd iw bas dofdoroe: esooim nok Zan woliol sofoelsinn ges eiveq ers Lamlan antvil etd e@tovoe1 ef[dainay to 1t6e¢mun » soqu nalSneqeb yideatebig eSmeinanic boot Yo noliat nesace eS6lolizaag Juisut to J @alilatey aleyriq «mo ttul fog foltdaubat .amalnenio gatbeved {Lore yidadoxw, Dim servons of hed ono worl eteteyo To . | sled? to motdibnoo eis vd ylletoxemmoo boafav ots dtof ere soulav eviielet oft unfatmteseb to shotver) onus odin Ympeiy © gacd yan OT .ovidadisanup baa ork elid a? ested hecnotinem ceiw taobasiber ul boon af segs 002 » jad? ,entwolll .etelseb tei’syo Besnelteqxze tog elfayp jan? dduoh on at ototT ,20oq 22 Tenkas ptedaw «i? af oefdayiav bus [uiesu em molithaoo to seisnal Yitevoittav to HarL od? «1 el eetwoo Yo ered Mosdwath eihy feubivibat bas escelirsecxe of? mo abseqeb doldaw noche to esodemtten oval? mot) evovret of .tevtends ait to BA eliavp salad steviesdo yd heoubortal yiliidaltev of? Gee Betiaqe Sax beriveh need evar! covplaros? alaiseo efosdaml Seseyo %o setudiasdse eft Yo sow yaw besalidar nea al emg vfovltedstinaup m6 @ILISL2) bas nett .2 .U oft Yo yrodmaodal detiftiens env ft ete ved wipeqsvold mol ototeyo ,.bnatyteM yelLogonas ome enact etolsfbhaos enlatoteb of seupinioed niatdtiooe yd Be gtoltaLumuoon megosyly to efoye Iamcsaee Sane Janome ort {fed edd ‘to oxte eid of Isom tO Phvomea aft Lo noida Mogoeal doltsthnoo ori? as wort of foldw to oltat sad y eid to xobal ae cl scold to done ' tdgiow yih Ineo teq a somos » Stowens cela aseti 10 donk § .tedeToO ed? 39 ROAM ettolineup InonwetT Tia “iutie “aseniart” eit af mofithnoe to xehal svalvdo Jaon ont gfiegooyia To eoneede to eotese'y add of tteg Soom ed? WT Ree @ et goldaninsatoeh aeyooyin Yo Bodden edT .tonade Lomign ton HYlw edeon edt to nolineghb to ewbeoot bedelideles @ gnixifosbyd .toroola di tr nejooytg od 10 notiadiqtoesg «ies \egoloo tenue ‘to tausome etd yrintioresieh fae esooaly of megony 1 0 mt scenooyin To Opataeors: as bexsenyxe o1m etLusell aolnse beta ef aigen: Xo olqmae dove to agifaeg A .adnom if etbifloe Sato? tans teq ed? eater ‘ 0g th In Chesapeake Bay, as in most places, the glycogen content of oysters follows a cyclic or seasonal pattern. In late spring a rapid reduction in glycogen takes place which is coincident with the fairly rapid development of the sex products prior to spawning. Low glycogen is reached shortly after the gonads be- gin the initial discharge of spawn. The low glycogen content is maintained with some fluctuation until the termination of Spawning when a rapid reaccumulation of glycogen begins. The time of the drop and the recovery at the end of the summer var- ies to some extent from year to year. Major changes in the nor- mal glycogen cycle, nevertheless, remain coincident with the gonad Gevelopment and the spawning reaction. In 1949 the major drop in’ per cent glycogen occurred over the period May 5 to June 15, and the recovery over the period October 17 to Novem- ber 21. The initial spawning in 1949 was about June 12. In 1950 the major drop in per cent glycogen took place two weeks later and proceeded at a slower rate. The initial spawning in 1950 was about July 3. The change in the per cent glycogen from the winter reserve to the summer minimum in 1949 was from 24% to 34, and in the fall it returned to 55% which held through the winter. The early summer drop in 1950 reduced the winter reserve of 35% to 9%. Oysters were considerably better in 1950 than they were in 1949, Glycogen in oysters, then, as an index of condition, has a twofold significance, one dealing with marketable values and the other with biological phenomena. The latter point in some measure influences market values in the following manner. The season of harvest, usually set by legislation, only partially encompasses the period of high glycogen reserve. At the end of the open season, April 15 in Maryland, "fat" oysters high in glycogen are still quality products. But at the beginning of the open season, September 1 in most waters of Maryland, oys- ters are still in a spawning condition with relatively low glycogen reserve. From the standpoint of production and conser- vation harvesting of oysters in September has these arguments against it: (1) spawning is still in progress, (2) quality of meats is usually poor, and (3) yield per bushel in volume of meats is low. The last two points are directly related to the low glycogen reserve. The glycogen cycle recapitulates itself annually with fair regularity. Knowing this, the conditions detrimental to production and conservation mentioned above, may be alleviated by postponing the beginning of the oyster harvest to the period in the cycle when. the high glycogen re-- serve has been reaccumulated or after October 15. Admittedly, this presents a problem in economics in a highly competitive industry. But again, the industry in the Chesapeake area and: elsewhere suffers to some extent when oysters low in glycogen, as they are in September, are placed on the market. The role played by glycogen in the biology of the oyster is only partially known. What is evident, however, is the in- timate connection glycogen has with the production of sex pro- ducts. The early season drop in the glycogen reserve is el eeulnes line edt suibnte amet, eh potage ofef al. wertet Ing, fenoraoe #0. ” goeblontos af detdw eealq eevnd ae OF votsq etoubomq Ree eld Lo Poemqe, aD #ed ehenos edd tedta yYldaece Dedlopet be Mego: tnetnoo aesooely wol ent - ecwrage 10. enrtios $ tanaa to nots Jantuaed ‘od Itdae nottawtowlt emoe ddty | oiT ,ontned negoeyls to not inLemmoom et biqsat o ponbri- cov commen end to bae odd te vtevooet edd hae got) oat peeved ef? at senaeds tote .aey of trey mort tnesxe ' } ods déiw é¢nebtonkoo ntene ~seoleddteven ,efoye. a 230. sofoam eid COL aI -toljoren aitawaqe edd bas tnemqofes o2 3 end bolteq edd tévo batawoce neyooyla anes ter emevol of Vi asdeto? holieg oid tows Ytevooet eid SAP » al Sf engl duode enw @20L al antiawegqe fLealiind eft) sveow owd ocatg Xood nenooyla dines seq al qowb page nt pat nwag 8 faltjiant est «estes t8ewole 2 ta Deheas negooyin tnen teq add al encode ofT 40 ylot 2 mont enw @d@l ak mess es Ree sommes off of ov1950r Tod ity arornet 3 bled -dotdw SSF of Doawmeer a1 [fet odd al pire Laat hast beowbert Od@L nl qos toemue elias ort O86L al istted yYidarebhlsnce ssew awedeyO ~he oF BBE | e2hCL at evey. oa .tofstbnod to xehbal mn on ,nods ,.sselayo al neg bae eoulav elfdeiedter dilw paifoeds eno _oonsa tittle orion al gutog tetsal. oT anerorer faotaefol d adie. ei? ,tenanm anlwolio? elt at seutev teoltan 1cohenraall eliatiasq viao ,noftaeLetnel yd tee Yitarwen « Jseviad tel hoe oit JA »OVteGoet nego ovina figtd ‘to hotrod acit ceqe. datd exeteyo “det” 4 bre fy seni mt Qf fleqa ,mosecee sege miantned of? te. tue. adnan yiifasup [ilis et asg *eyo ,bneafyisi to exsdaw Jeon L qedmesa sa giouses A wol ylevidafet diiw nofi tines titnweca » mt Lfkie ogonioo Bas ttolsoubotq to datorbaade ed? mori +evteaet gicomiatws eseis asd tednetyec ml eredeyo te % grid sewn to yiltinao (9 esetnoa at Elite wf ralavec e (f) rth: 20 enmufov nut t Poteau seq bleky (6) baa 4 008 Yiieuer @f eit oF bedeler yidoerlh om atatra owe deaf ot? . vol. ae tfLeus! sosolatiqsoes elfoyzo asgooy ts, ett .ovreses neget eno lttiaos es ,eldd. gatwomt wed ixalupe aint diiw, govoda herotdnem oj davaeene bre aeltoubotq of Inte medgeyo ony to = ponerse vod old. gelaogieon yd botatvelfa: eet conooyin catd ‘add med alors ond rt ‘bolveg ed? OF Ti etibetiiahA af rododod adhe 10 Sesgalumuoonet meed pep mya £8 oapoe yldsic a al esisodooe af mefdorq # edderem ‘brs ger ol neces ei ort a2 yrdepbak ond whlage Sm ayes ehenoenis at wol eredeyo oedw ghedme ede of eset ine erady Jownen od? 0 heealg ete vtedines qed at on ¥ “Mepevo odd Bo ynofold mit mi nogoarts vt hoyate efor. eri onl oct £2 ,tevewot ,ineblve of dad! stor poe resi eon xoe ‘to molsouborq oly didiw eed aenoorts noldo sf svrenot negooyly oid af she noesed . Ph eile: ts concurrent with the rapid production or maturing of the eggs and sperm in the gonads. The fall accumulation of glycogen follows the termination of spawning. To further support this relationship was an observation made during the summer of 1949, The initial spawning had slowed down and the glycogen drop had ceased. Then egan a slow rise in the amount of glycogen dur- ing the middle two weeks of July. During the last week of that month the gonads increased in thickness and the glycogen simul- taneously dropped rapidly to a new low. In a lesser way the mid season spawning-glycogen relation repeated the initial re- action. A simple means of determining the volume yield of oyster meats from a measure of oysters in the shell has been known for many years. ODr. Caswell Grave in the early part of this century calculated by displacement the volume of the whole oyster in the shell and compared it with the volume of wet meats. The ratio of the meats to the whole oyster can in turn be converted to a pints per bushel yield, the index generally used by the oyster packer to classify the condition of his oysters. Grave then went one step further and compared the volume of meats to the volume of the shell cavity to eliminate the discrepancy in- troduced by the individual differences in the thickness of shells. On a wet basis the ratio of the meats to the shell cavity represents a condition factor for comparing quality be- tween groups of oysters. The weakness in this method is the use of the volume of wet meats which may be bloated when exposed to fresh water. Grave pointed this out. Dr. A. &e Hopkins in the United States and Dr. C. J. Medcof in Canada much later employed Grave's methods adjusted to the dry weight of meats as a quantitative means of comparing quality in oysters. The index called the Condition Sactor is a product of this latter method. In Maryland and Virginia the Condition Factor has been used currently to indicate relative differences in the quality of oysters. The range of "2" for very poor to "16" for excel- lent was arrived at empirically. Jith this scale of quality the changes in condition of cysters was measured during the ex- tended period of freshet in 1945 and 46. The gross appearance of the oysters did not always show the degree of "poorness' in its true light because of the bloating caused by the fresh water. When measured by the Condition Factor procedure, which excluded the excess water, the true value of the meats was indicated. In general the Condition Factor analysis has a similar cycle to that of the glycogen cycle. The per cent dry weight of oyster meats from which can be calculated the total solids or the moisture content is utilized in the glycogen and the Condition Factor methods of deternining quality. In itself it has a place in comparing oyster meats with other foods. A common measure of food value is the total 22 ayne wit lo safavden wo mold ee 8 odd a @ menooy fn to nolfefumuoon {Let elit dtoqque toldad oT .nnl a te yen rye ond rae s020L to tonmve ed antanb oben noldavaeedo ae saw qide Bed goth nencoyts ed? bas pore Sevalt basi pitoraqe fete “tub aenooyfn to tawoma edd at eel woke » qaye! «! dedi to teov teal edd galex’ .e ket o evoow owl oisbia i - wf srt 2 cerooyin ed? San seemlold? ml Beuseton? ebaao ei? var teceel a al ,wol wen 8 of ~ibiqet Beaqo: “ot fold tas e(s begeecet coldalet enecinantenal a “eteyo to blety suufov eae? yaiuhotedeh to sasen elouls.; tol awoml aved aod [fede edd al esetavo to eivéeen a me “ie "mwIneo otdd to taeq YLase ed? at evewto Ilewssd .c .Beeee at tosJeyo olodw eff? to onufov edt taenesalqelb gd ‘pedal oiT ogee Sov To emulov ots dilw 32 bersqmoo baw £f hesaevnoo od maiud al aso tetero eLoiw eds of std od ada oid yd been ¢qiletenes xebas ei? ,bLely ledaud eves) ,eteteyo sid to molslbaco edt yitiasafo of — og ateen Io erwlov eid beteqmoo Sue toddwt qeds eno ent yonsqesselh edd edentntie of ytivao Llede ed Yo | So ssemlold? etd al agonetett If {aubivibat ed? d &£ {fede edd of stnem aid to oljet eft elead Jew s a0 -od yiliaup yalasqmoe 402 tovor? aoltilbaoo s adnesemgel een wit sf hodjem eld? at esomiser eit ,atetc7o to aqw 0? bosoxe neste beisold ed yan doidw sieom Jo To. em «?uo efdd Hetaloy ovet) «1 tooboi .b .° «tl boa aedede Sodia’ ed? al ankdqo! «ft 4, -at | wid of Boteutbe ebordom atevawd hoyolfqme tetel Aomn al ~yiifLeup aalteqnos to eacem svligz3iinaup s er esnem Io td Porton e ot motos’ goltingo: sd? belfao xebat oiT .atedm bod? om medial | need ea! a0 oO artd atatnnt¥ Dnn baa fynais gelivup eid a soaaenel 1" 5 evidator edaolbat ot yf next -Looxo 192 "OL" of good yrev tot "S" to ennax eT cee yiliaup to efeoe eld? dg! evifaolaiqne da bovieaws “xo ot nnlaub Dewvesom aey sxeteyo Te molilbaoo al sese eotetseqds seoty ell o> baa aLer ai tedset? to vo tog Be et at “seostoog" io eomeb ef? woe syowle Jou b&b eseds . eiesew det] odd yd beauao naksaold edd to sanaced sdakhg behuloze dotdwy ,ewwbeovorg ae oD) ed? yd beuesed & shatveolhnl aaw sisem ait lo omfav ents sti econ as nee anitmie 2 sed sleyfoas oe) (3 Bedihnag? and w LOO senooy ts edd to | Ra. ed ano doldw moxt sdaen tetsyo Yo tdglew yb Iaeo 09 et besiftdy <1 tuetavce payed edd tc sbifos ot ond i pry aaininteateh Yo sbhodiem tojoc% foe laa oi? Daa aegooyts if aseon t98s eyo aatenaune ni esol s eal $f Bfeati at oydk be < fasos ed? elf ouiav boot Yo eivepem: Gonmeo A piven? bes oct iw: ss | Solids. With this index it is possible to relate the unit value of oyster meat to unit values of other protein foods. As in the other methods of quantitatively determining quality of oyster meats, this technique may be used to compare one group of oysters with another. With methods that accurately and simply measure the qual- ity of oysters, it is possible to compare the effects of changes in the environment, inherent differences in the individuals and cultivation procedures on the condition of oysters. Fundamen- tally it must be known what constitutes a good oyster and why. The “why" is the hurdle the oyster biologist is working with. Some of the measuring devises he may use are explained here. Two charts. 25 AN te fc aay i ie! ; ghaw edd edalet of efdineo > |) gaboot mletorq tento To sevle i 0 ee Rfeup prkalsreted kyla, i d @8O%G eno ensqmoo OF Beag ot yam exp! ot eld? .tde amar a oo Gpedtioas oto iw, -feup orld osvermem yLamte bas qLetenwvooe tad? shodiem a Gennes ‘to sjostte est ermqmoo of oldtsasog ef Jf ete By base eloubivibnal edt mi eoonerell lh snenedal ,dnommorlva -temebivi ,eteteyo to noltthbaod edd mo esauvbesow aol svdwv baa redeyo boog » aetuitienoo Jedw awoml ed dom efidlw noldvow at defnolold tefeyo odd ofbamt eit el % sete bentalqx6 eta oo» yam ol sealvebh aniswosem odd, eed tado | Ate Gt a. . IG 19 1g i7 Yr SOKkIDS I ; . Fai Souny's an : , VA Hane oN S$ ee, ; eae 13 ek Aguas Aa! A ‘ . 2 ‘\ at Beans ‘ 3 iw eve K . BA id ii REND 7 i arias ¥, a a x --KXHACKETTS BAR, ‘ i EU TOLUy Susanne aim | | ‘ i a) y ni ° y oN sagt \ x GOnNAD THICKNESS \ \ aN i. is . x I ES Moe —_ Ss ~_ ‘ NAN i / si mG a : an e \ < ( x / ; ‘y PN oe 4 = \ ~ N ' oe S | \ ; \ } - d x TE iii 7 fo ae a So ae ad ZA Cea ara ee eis ae, ‘ [x , m K Nese on ani i 1 ! Ji LL OLR vs AP. ™ Ju J A S 0 N 4949 COMPARISON OCF CONDITION INDEXES WITH GONAD DEVELOPAIEN Ss SFAWNING vE OYSTERS On TWO BRBAKS eS CHESAPEAKE RAY » ’ ' yt) J * ’ ower 4 | : \ y | ( : ‘ - : \ 2nwW > 1 te 7 ( x ° GLYCOGEN CdRY) Ye Pad ; \h CONDITION ACTOR oa ee ies \G ae ay \ i De) an & sna Me Up UR A ang a SOW Ho ‘ ny [te vA 7 ( 7 SoLIDS , © IN \ : Pe GLYCOG ER Vt 1 5 ; es i: \ [nee ca nie ee vA i / e 4 RSS 7 SiN thie Ue. a aie I. ji Nie) pale en ; 1 \ ~: x We / ‘en x Ay/ Wee 2 | \ Pr diiioliuans (ies, Ci) Ri fi Gah OM he a Pa ers x aN font NENG py a ¥ n~ \ 7 y nh { at ca \ Oey i / ae 4 \ / \ U ij a: ‘“ a ' of EE SSIES SEMA es My re 7 [Ne 7\ K- - —-MHACKETTS BAR * GG . ~ py GONAD THICKNESS ae u AVN \ v \ Nm ; Ay: M y Ju J) A 3 i Oo N CST ete SIN Ed ye comets fee ens St a th a i950, COMPARISON OF CONDITION INDEXES WtTH GONAD JEVELOPMEN: BAY. Y SPAWNING OF OYSTERS ON TWO BARS CHESAPEAKE P ; Puss “Hetowy eo itewe WAN 1 A RR sO 4 ity EVV RMA . ARORA Hint Rwertsjeyore bers wither) pie an oe ao ' ‘ tay } \! WONG ah Mae ly vy ih Hic ws Saius ‘lin Wet asta Cal aaa sab DI fe : : yy ny au { a " Pia ins , @ c ; t ae A mitt Re ne 7 > 4 PAT: is.¥ Shy hig he yeu bch btn ye Beet: Shellfish Sanitation Research Program* By C. B. Kelly, Chief, Shellfish Sanitation Section Environmental Health Center Woods Hole, Massachusetts In 1946, the Public Health Service published the first edition of its manual of Recommended Practice for the Sanitary Control of the Shellfish Industry. In the formulation of this first edition valuable assistance and guidance was obtained from discussions at meetings of the Shellfish Committees of the American Public Tealth Association and from meetings of the National Shellfisheries Association. This assistance has been continued through succeeding years. Invariably, the subjects which received most attention during these discussions were concerned with bacteriological procedures, and what would constitute reasonable and practi- cal bacteriological standards for shellfish and shellfish pro- ducing waters. A standard bacteriological procedure has since been developed, and has received universal acceptance, There remains a deficiency in fundamental knowledge of the bacteri- ology cf shellfish. Sufficient scientific data are not avail- able to establish such vital facts as the relative survival of coliform organisms and pathogens in sea water, the rela- tive ratio of coliforms in the various species of shellfish growing in the same area, and the bacteriological behavior of shellfish as they proceed from the growing area to the ulti- mete consumer. ‘Without such knowledge, the practicing shell- fish sanitarian has no standerd on which to base an intelli- gent opinion or interpretation of his sanitary surveys. He can not establish the bacterial density at which shellfish should be allowed for distribution and sale, Recognition was made of this situation by the Service dur- ing the compilation of the first edition of the manual. As soon as possible after World Jar II, steps were undertaken to estab- lish a research laboratory in which to determine these funda- mental facts. The first step was the appointment of an Advis- ory Committee composed of bacteriologists, biologists, and sanitary engineers prortinent in shellfish sanitation. State and Federal Agencies, as well as industry, are represented on the Committee. The first meeting of the advisory group was held in March 1948, in Washington, D. C. It was decided that a research Presented at the Annual lheeting of the National Shellfish- eries Association at Atlantic City, N. J., August 22-25, 1950, ay 26 *nompori, dorsenef totved tas Mae, i ime i. nolisec noliatiage delttfonde Chmtahin de ae oe toined difcet Iadnemmortvad - i siveanmioncaat .gefol zbool ‘ texlt oft bedeliduy eolvres difeal offdwi edd .od0L ma Grssinss eit wot eoltonts Hebaemmoceh to Lauaen etl to a eldd Yo mnoldoafuot off sl ,yiseubal Heltifed2 ext To |. bealoddo éav eonebtuy bas eonntetnes eldaufav moldtbhe! “tt To eseddtumod daltifedé edt to enntdoon 32. anolsevosht edd To syntveon mort bra noltistooses Adiael otfidei ase “pec Gat eoradelees elit ,.toldalooses. solsedaltifede £ efteoy galbsesove dayonid bem noivnedde teom bevleoos doldw atootdve ent eVidelnave faotpolotaetonad dilw benseones eses snotesunelb eeed? | -itoatc Sas eldanosso1 etuilitemoo biuow tadw bane caeee eon defiflede base dettflede, wt abuabaedo feotnolol sedae ‘eonle sad aetubeoowy Laoltnolofsesord bishacite A 9 810989) erotT ,e0netceoos LInetovins bevieoer sai-bus ,d5ecoleme sfiesoad add to egbolvond Letaemabaet at yonetstteb a a «ffavea don ore atad oltitaeloe gneleltiue. seltilede | =) fevivuse ovisalet oft an edost. Lativ down delidadus. ae ~Olet of? ,tetow see al snegoddaq Bue euetnento mate delitferte to velowgs suoliav sdd af eptotifos to ofdm te tolvaried Leotpofoltetosd aid bane ,#e48 onse odd ahs “Lify eid of seta gniwots edit nott’ Besocr, yodd em der ~fiecie gntoliosiq odd ,enbelwort doue duods!) .zenvedeme “Lifeinl ae eeed of doldw mo Susbaetes on eat nstand tae of seyovaws ytetines atd to moltsterqiein! 10 nolakgy deltifeia soldw je ytleasd Iabwetoad eft delfdatue F eofse ban aoltudiavets +ot bewolls od ¥ “mh eolvts® edd yt noltautte eid? to efhen eer nots lagosehi moose t/.- .faucen old to moldibe tenlt- edd to goliallqnos cf s@atee ot nelotrohu otew eqese IT se) blsov sedto afdiaee eabavl sxeis entuwroteb of doldw at ytodarodal dowotet Bi +SivbA ae lo saemintogqe ed? saw goete fart) sci’ esioe? £ | bas ,atelnofold ,etelnofLoltevoad to bhoncqmoo eed) tome edefc. ,colsdadiaas detilfede al sdnentnoig eteonlnae paogs fo Deineeeiget oi .ytteubat aa [lew ea ,aetonend rye f : edo? i ‘ wien Mona mi blo sew quorg yroelvbe ed? To gh he jaatt eft | Soteeaet & tzid bebtosh eaw $1 49 0G ,aotnaltdeal at. efiliede Isnciia: eit To 3aiteo. Launad eat da bed eOSSS Dargah pal of yrtld oltneliA te nolinlosovaa as laboratory should be established at Woods Hole, hassachusetts, staffed and operated by the Yrublic Health Service. Selection of this location was made because of the availability of exten- sive laboratory and library facilities, and the opportunity for technical consultation and advice at the three scientific organizations devoted exclusively to oceanographic research. Also Woods Hole is near waters of various degrees of pollution from the metropolitan communities at some distance from the station and the few isolated areas in the immediate vicinity. The Shellfish Advisory Committee recommended the follow- ing schedule of investigations: 1. An evaluation of existing methods for the bacteriolo- gical examination of shellfish. 2. The determination of the relationship in bacteriolo- gical content between the shellfish and the overlying waters at various levels of pollution and temperature ranges. 5S. The study of the relative survival of coliforms and enteric pathogens in sea water anc shellfish. 4. The study of natural and artificial purification of shellfish. Organization - The Woods Hole laboratory is a section of the Research and Development Branch of the Environmental Health Center at Cincinnati, Ohio. It also maintains a close liaison with the Shellfish Sanitation Branch of the Division of Sani- tation which is responsible for the shellfish sanitation con- trol program of the Public Health Service. Thus, the scien- tific findings obtained in the laboratory may be applied at the commercial level and in return, the practicing sanitarian has the aid cf technical and professional advice on his field problems. ‘ith the close association of the two units, it is also possible for coordinated guidance of the shellfish ad- visory group. The Woods Hole laboratory staff includes a chemist, two bacteriologists, a biological aide, and a stenographer. Lab- oratory facilities were first located at the Woods Hole Ocean- opraphic Institution and work was started on problem one: the comparison of bacteriological methods, in May 1948. When suf- ficient information was obtained from this study, standard bacteriological procedures were formulated with these, it was possible to undertake other investigations, However, it was soon found that the allotted space at the Joods Hole Oceanographic Institution was inadequate for proper functioning of the lab- oratory, and negotiations were started for the acquisition of additional space. Arrangements were finally completed in May of 1950 for the use of three rooms located at the laboratories of the Mish a nd Wildlife Service at woods Hole. The laboratory moved to the new quarters in June, A | bh Wied ul a ile eMC COLCA VET ee (i ' me LSM Wit A Tey Urea nti he ca Lib efi i ‘gattoeudonerai ,ofoll coeds te TK. 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Basak mee “det atid Yo gninotionut mmconq Ok edaupebent cow motsert a Yo motyielupos ot rot hedustes otow Snottattogen Sag gran yam nt bad oiomon yifant? evew atmorengaxts .eoaas fae, ndltoionadel add ds betaool smoot eondt To hig big TOL! Trotetodal oft elo shoo: tn solvass slLIplic fe. one mh eiadtanp ue Summary of Results of Investications 1. Comparative study of the methods for the bacteriologt cal examination of shellfish - Laboratory work on this project has been completed, the data have been tabulated, and the fi- nal report is in preparation. Results of the study indicate that the procedure for the enumeration of coliform organisms as described in the Recommended Procedures of the American Public Health Association is practical, and could be followed with little modification. The same conclusion applies to the 1 a arated technique for the determination of entero- cocci. 2. Ratio of coliforms and enterococci in Shellfish and the overlying waters - In these experiments’ three species of shellfish were plantecd in a laboratory flat, and exposed to flowing sea water which had been artificially contaminated with known and controlled quantities of pollution. The pol- lution was supplied from a reservoir which contained a dilu- tion, in phosphate buffered water, of the unchlorinated Imhoff tank effluent of the sewage treatment plant at Camp Edwards. The pollution reservoir was changed twice daily, and most of the experiments were continued for a period of four days. Studies were conducted eat three levels of pollution; that of clean water without added sewage; at coliform MPN approxi- mately 400, representing moderate pollution; and at coliform MPN 1000 and above, representing heavy pollution. They have been conducted at three ranres of temperature; 0°-5°9C, 8°-15°C,- and approximately 20°C. This project is now nearing completion, and it is expected that results will be available b; late fall. Although tabvlation of cata is not complete, the results to date indicate that shellfish respond quite rapidly to changes in the bacteriological content of the overlying water, usually within twenty-four hours, and, in some instances, within eight hours. Although a definite ratio between the shellfish and the overlying waters has not yet been computed, it appears to be relatively constant at the three pollution levels studied. It has wvecn detsrnired that under similar conditions of pollution soft clams show the highest coliform index of the three species studied. Oysters and hard clams are of the same order, with the possibility that oysters range slightly higher. At the end of the pollution runs clean water wag allowed to flow over the flats, and the shellfish were examined at frequent intervals for a period up to seventy-two hours. De- creasing the coliform density of the water affected a corre- sponding drop in the coliform wntent of the shellfish at a rather rapid rate, the process usually attaining stabilization within a veriod of eight hours. 3. lussel Studies - The Shellfish Committee, Engineering 28 yfolvegos o 3 to OTE mF 2G eit 7 DIO OeLorc elcy no Stow yaoustocal = gatitiets To Gol sanioes «ht oft Dae ,beteluiad mood ove eteh edd ,béselqrco net etsoibal youde odd Yo ast{isek ‘»aottamnqenq al sk dc ‘enainesto mrollfoe to moltatomune eid tol etubeso1q en} nsoitem. ett to eetubeoorts bebaemmooel edi al bed t 2035 - bewolfot ed biuco bas .leoltioetq af aolialoosed dite ei eid o¢ soliqqa soleufonos enes efT -.noltsolithon efssiin -orei® lo dolidentmeted old 102 euptadoe? tesloibaacete cb ol whe Py aa if ae feltifedS st. losoposeias Dre Lc LO OF 78}: + @ fei swW aait SB errs Pm i f} Oo @aloece semwit*staumigsqxs esedd at Vi-B od bosogxe bas daft vtoterodel e al Seinsiq stew dale bed eninainoo vifelottiiue need Sot dotiw tedaw see pay “Log oT .moltuifoa to seldiiaaup Selflotsnoo baa 4 s ~ofib a beaistnoo doldw atovtese: s motl beltiquse dare Viodnl betenitoldonu etd to ,tedaw Setetted etanceodq nig eshtewhl qed te tanefa Inenteestd onever edt Yo taenlTie to deom Dae ,yitsb eofwd beanedo eaw tlovteses nolomif eyed irwcl to bolieq e& tot bevnltince etow elneniqagaey +f rs a = ¥ tadt yrottullo: to slevel sexdit ga betoubnos eter eelbotey etxorcs VIN mrotfiioo 3¢ yenewoer Hobbes jvoaiiiv tedanr agee maottfoo ja hana yaolttalfog evarebon gnizacesicet ,OOR ever YodT ,ttolttellog yveed gahinoeeiqet ,ovods haa OO gP8l-9B .9°%G=9O pormdsteames To Bennet cent! ta hotoub gtoltefqmog galteen won ef sostom sidT .0°0S yleoJjantxougam ef{et etal d ofdalieva od fflw aifvsert tadi Setoorxe ef gag , ra eifweor od ,etoelqmoo gon si eten To noltsivdss dawoddae eoyuacdo of yLbicaa etiup Baoqees Aeftilaic genie sisoldal 1D: yfiaues ,totav Gaiyltevo etd Yo tastnoe Iezoinolol«otoad amm ddgie micitilw ,eeomssent-omoe mi .Dam ,eived t00l-~ytaews ae pie deltifade ed} asewted olteat ediniteb s dnwois lA Qe of eiseqqce Ji gbeduqmoo need doy Jon asd stetaw gantry iieves eveltbusn elevel moticlloq eon? edd de dactence ~leviiate “Jo snmotiibuco asf{imte teboy d@o70 hetiei doo cea Ts Uy od) lo xebal miotifoo Jeendaid of? wode emslo 210s aolgem amee ei? lo eu enefo brad Sas aveyayo ,hetbusge aulooqe igs et@igtd yltiuile onnet axetego tedd ytlliclesoq edt dilw (ae hewolf{e paw sets aseLo ent aot¢ulfoq eit to bare ad? JA ta bentwexe otow deftifeds edd Bas ,sdelt edd tevo worn eed 3 .exnol owd-yinevee of qu Boltoq a 10? alevreinl Jnonne *eTI00 8 Hetoeltse stotew edd to yiteneb miotifos edd sat a d9 doliffede oid to tueda wo mao tifoo eit nt com salonee moiiesif{idaie nnintsaistea yfleven aesooag odd ,edet blast tend: eae satvod gigte lo botteq a mide. gniteonigne ,eetdtmmod deftiiled= edt BolbuiS Loeag! 4. ‘ - 8s ih } Section of the American Public Health Association, at a meeting in Boston in 1948, petitioned the Service to include in the pro- gram of activities a study on the cause of high coliform scores obtained in mussels as received at the wholesale market. This problem has received attention as often as time permitted, and the studies will continue until a satisfactory answer has been obtained. Part of the study has included a careful check on lots of mussels commercially dug and shipped to the market. Bacteriolo-= gical examinations were conducted on mussels stored in bushel baskets for 24, 48, and 72 hours at room temperature; shipped to New Bedford and returned; and shipped to Fulton Market, New York, Up to the present time the results indicate that the increase in coliforms is primarily a function of tire and temperature; but it is also dependent on the extent to which the mussels are cleaned of adhering mad, as well as care in handling after removal from the water. 4. Seasonal variation of coliforms and enterococci in a polluted area - Hel Pond Studies - kel Pond is a small tidal area located within the village of ‘foods Hole. It receives a con-= siderable amount of pollution from dwellings and semi-public | places built around it, and therefore, was considered to be an ideal area for the study projected. Accordingly, samples of water have been examined from six stations, and hard clams from one station, at monthly intervals since August 1948. A sanitary survey of the area has also been made in order to correlate the bacterial findings with the locations of sources of pollution. Vork on this project has proceeded to a point where sufficient information has been collected for the preparation of a final report. Definite seasonal variations in bacterial densities have been observed, with the low coming in the spring following the period of lowest water temperature. Some correlation between activity of the shellfish and bacterial content also was demon- strated; the hard clams showing a greater coliform content in the summer and less in the winter, 5. Survival of coliforms and enteric pathogens in sea water- This project was suggested by the Advisory Committee at its meet- ing at Woods Hole in October 1949, It is in the preliminary phese; a project outline having been compiled, and a standard technique developed. In the first part of the study suspensions of coliforms and salmonella, both in pure culture and combined, are prepared in Berkfeldt filtered sea water. These are examined periodically to the point of extinction. Later, experiments will be under- taken in model shellfish flats, the shellfish to be supplied with water containing known concentrations of coliforms and patho- gens, and the water and shellfish will be examined after various periods of time. These experiments will be conducted under dif- ferent temperature conditions. It is hoped that these experiments 29 iy) Bites p aa enoteskeon adie | | wom edd af ebulonl of eo lvared a Ott f “aeneos mistifoo datd. to geugo eft ao yhuse ne etd? dexter ofsselodw edd ja beyleset es aloes brit ,botiiuueq- omty ea aedto es aolsaetia beviess aeed ent teweade wtotoatakins Bi) fiing enntdnco filw PT) Mi fo esol mo woes fvtease 2 behilonl enti eeeas erty ov) ‘e@PotretesG .teltam eid od beqaide base sub yl Latorvontoan Fereud al Serote efoeann io bedavbao9 Stew snoldsatng od becqice yeusateqmed moor Ja nagod ST boa 5 28 not edtoY wo ,dedtail aodLvi of beaqide baa gdenxudet baa bid at seseiont odt dadd etoolbal e¢ivnes ert « orld staezen ba tud ,oawtavogie?s Hra eat? to noltonut » yilaamiag e boasefo ots efeeem edd doldw od deoixe edd cto trebaer zs ovk nor) Iavonet aetie aalibaed mi eten an Ifec ae «baie gules (nea \ ent lossoootstae bas enol p22 to nofteinxzay fanoebel petn Ishis Tlome s ef baot Tee Babul Dot Soa = Bene. e100 8 sevlevet df .etow nbos Go ouellily edd. aed ot idna Enon fam eannitfewh pa Aoltulfoa Oo ¢Anona me ed of betebienos baw ,evoletedd bac ,dk-Savonn Shinde to selqnes zinathroses »Detoet ox woud e ond sot OTR mov? emalo based baa eetoliets xle moc) Deninaxe need oe . yYindines *£ ,8deL + mareytias eomte efeviedal efdinom te . edd eialeti6s ot tebro at eban need oelo ead aete atoltuliod 2o soowos Io shoitegol ond ddty snsthatt ge dneloltinm oredtw datog a of bebeesorq att Jost org: elite .\£ertt a 2d qoltancrety edd s0% Bedoelfoo mood as nokia eved Beldiaceh falnretoad al enotiaiaav Lancasen ethultet) aa ait gaiwelfot nalage end al gaimeo wol eit dilv ,bevTemeg foevwied nolvalearoo enod . oud etequed tod OT daowod, om ationed sew cala taednoo Iataetead ban deliifeds ocd to wae ml Faadnoe arotiflos tedeets 2 patwode suelo Siar oid ue cian edd at eeot bes 8 moe peear at She ite i Ee ei 6: Bry kat ass ¥ ; Z Fare) 3 9 psy rere ~7 Gan ry ty rae SoS Rea niee } yioalv vA a" Pee Fean* ua oe eee ef: ieraatanheenc edd mt ak of oer. gsodotoo nt alot xhooW atacand B ban ,bollqmoo moed git vad extivus ooel oa 8 46 '- 4 betolerad Onp ee geno ?foo ‘to eiolanegene yhuge oft to deg fast add a Hewett: om ,bealdnoo. bas ound Lye emg mt dvod ,sfienemias, “yllas thotrer, beninexe eva evel. vredaw wes hevedlly thleotae “mgebrin ed [Liv ninentteqxe tated snotiontixe ‘to. duleq s OF hetlqaw: of of teltli sda ont) pode? deritieda Leen of soitey Dae enalifoo to srolieaxtossneo avon gatatatnoo tedei epolkav ttle beninexe of [ftw dabiffLoda bine sotaw edd Ded “2th wehas hetoubnoo ed [Liv ainemttogxe emedT wets Bo sinoniaenxs ofadd Sadi beyod ef FI. vendtdtoano oar will result in the establishment of the rate of absorption of coliforms and pathogens by the shellfish, as well as the rela- tive concentrations of these organisms in the shellfish and the overlying water. Rate of cleansing will be determined by sup- plying the flat with clean water at the end of the experiment with frequent analyses of shellfish and overlying water until the coliform content of the shellfish is the same as that of the overlying water, and pathogens are completely eliminated. Sunmary - The organization and aims of the Shellfish Sanita- tion Section of the Environmental Health Center, have been de- scribed. The purposes of the laboratory are to conduct studies with a view to the development or improvement of bacteriological methods for the examination of shellfish waters and the collec- tion of data leading to the development of reasonable control standards. The unit also operates in collaboration with Fed- eral and State control agencies in practical field investigations in the sanitation of harvesting, processing and marketing of shellfish. A brief description has been presented of several studies undertaken by the laboratory. Some have been completed, on which reports will be available in the near future. The laboratory has to date, made an evaluation of methods for the bacteriological examination of shellfish and overlying waters and has collected sufficient data under controlled condi- tions to establish the relative concentration of coliforms and enterococci in the three svecies of shollfish and the overlying water. More specific information on the significance of this relationship will be obtained from similar studies with patho- genic organisms. Other studies in progress include investigations of the handling and marketing of mussels and the artificial and natu- ral purification of soft clams. ‘Work on these projects has not yet progressed to a point where definite conclusions can be drawn, but the studies will be continued until sufficient in- formation has been obtained. 50 iy onageoad to od £ ga pe ILow- ex derrtteda: eed ents ee gh aba rebacel wv gat: o. Jaomixeqxe eld to Bae ott te xegew meoto dd tv Ol Lktiay cotar grityfaove Bae deltiffeda to seorglens Ine edd to tadd ae emge odd ef deltifede orit to. taetaos maotth boteatmele, Tied etatos ong ertegondag bas utah aby jaad base eltecei® tit to amta bits nolivasiney so ent’ = 3 ~eb read oped ,tetqed difest Iadnennotivas end to nal, eolbnds touvbnoo of ems yioderodel edd To sevoqthy oft. of Isotnofolieiead Yo tnemevorget- to imemgofeveb aid of wely)) -#oalioo ei? bne etedaw dettlfede io nokteminaxe edi “tot ef fordnos ofdancesen to Ienaol ev ob ef? of palisel aiab 9 efhet dtiw setiatodaiios al cetenedo oafa Jing edT “ebta anottasiscoval Hiott Isoltoanc ai eelonens fortnos etadc Lo paldoxttan bas gilaneoorg apnksaeraad to wee gelbuie Inteves to bet neces aood ead not? ginoeeb to! oA Aolciw 0 ,otelqmoe mood evan anol totsicdal edd td neds voroiut ainea odd a pidst Leva ad {ilw aboddem to molbtanlsye on efer-,eteb oF eat ctototodat a gatyiveve Dae deltilede to nolieainaxe feotgototetoad ¢ vkbaoo belloddmos tebaw atebh dnefolTive besoolios aad & Bue umrcilfos to noliestysenoe évidalor oft delldstao gaitytsevo ext bone daltifeds to esfoace sect od? at. fosoge Bids t¢ bonmoliloaute ef? mo noldamrotat oflicsge ex0M (4 ne add tw. wotbuse telinte mort Bentaido od [fiw qidsadl bps: sone toma per to enojientécoval ebulont seekson mi esefbite ned emian boe fatoltidw edd ae efoneum ko galtseltam Sas gon Bad etoetorw veeortt ao Mov .amets dios: to nots aott Patt iW ed seo anolenfonon et inkieh otedw tntog s od beceengeM “nf tneloivive f£fing Bounlinos ed [ftv aofhute odd ehbeniaido aved ead aA 3 ee } iS Observations on Soft Clam Mortalities in Massachusetts by Osgood R. Smith U. S. Fish and Wildlife Service Newburyport, Mass, Introduction This paper is to report a mass mortality among soft clams, Mya arenaria, observed in Plum Island Sound, Essex County, Mass- achusetts, and to compare the occurrence with similar ones re- ‘ported at other times and places along the New England coast. These mortalities may be a primary cause of the present scar- city of soft clams in lassachusetts. Mortalities in Plum Island Sound, 1949 During the summer of 1949 we made a census of the clam population in Plum Island Sound, principally by taking two-square- foot samples. By the middle of summer it became quite obvious that clams were dying from some unknown cause. They were in var- ious stages of decay, but in normal position in the mud, often with their rotted siphons still extended to the surface of the flat. This is the condition I am calling "mortality", in con- trast to the loss of clams by predation or other causes where the clams are removed bodily. The mortality was most obvious in a bed of planted clams in Rowley, partly because there were plenty of clams there where- as they were scarce elsewhere. On June 15, nineteen live and five rotting clams were dug from three square feet, a 21 per cent mortality. By the middle of July, 98 live and 75 dead were dug from ten square feet, a 45 per cent mortality. At Hale's Cove, about a mile and a half farther up the Sound, the proportion of rotten clams was even greater, though not as obvious because clams were scarce. There was a fair scattering of 20 to 40 mm. clams over much of Hale's Cove, estiwated at a density of one or two per square foot, but thicker in places. Forty screened samples, each two square, taken between May 24 and July 6 had 78 live and 27 cead clams, a mortality of about 26 per cent. On October 18, only five live clams and 148 dead ones were found in 115 square feet, a mortality of about 97 per cent. Clams which we planted for farming experirents fared little better than the native stock. In this case the horseshoe crabs bodily removed 92 per cent of our planted clams, mostly within two or three weeks after planting, but of the remaining clams, 318 were recovered alive and 914 in various stages of decay, a Sl re vit scale | Rae, die jag (ettieee ' fae Heltt «A 5 Oe _Sroryetie il iN ~anals viox naoms “yotiadton seam 3 oqo od al i roqed basil evimuod xecsd ,Sawoe® Hinlel mult at bevresdo .aiam ~o% emo tallmte dilw eonetanooe ers atagaos oF Han yagg o20509 bral pad we edd yools nooskg Bae somty toddo ¢ ~t208 dnesend ond to seuao yraritia o od yam ecottilays sSiJonudioancei ct omslo dios | aslo oid lo sveneo.s ebam ew. 880L Yo tome add nat -e1ayoB~ow! gntted vd yflaqtodieq (bawed baalel moli at anole auotvdd st tue engoed th tome to efhbin ed? yo .colquim -tav nt ovew yedt .seveo avominy emoe morl yelyb ote Metto bet edd al noltinog Lancon at dod Vwsoeb to sen eit Io osetane edd o¢ debnetxe [ftie exoigte botsot “roo at .,"yatiadvom” galiino ne Tf woleibxoo edd ef aide , et xt aninse teigo to foldobotwdy yo emeio to seot odd) -e¢@ilbods betones hn Mm ' euefo betnsia Io bed a nt awolvdo Jeon saw ve tteduel -otelw exedd ansto to ytaels osew ores esueoed yitieq «ye bas ovlfl neetenta er ert ao votorwecto eo'tses ate 1 teq [2 2 ,Joe% oiseps cord? Henk anh stew one fo sre emew beed éS bia evil 88. .yinl to efbbin edd yl .y hited e(eifsairon, Jneo on a2 8 ,gecl OTE HPS red gOaNOe oid qu tondtet led «2 base ollw a deode, pevot etoralt : > \@a don canodd .tetests neve tow analy. cioltoe "lo molded ‘grieeitave tial 2 saw eredT -o0tRse stew anelo exuaged” / (@ de Detorties .evod e'slal to coum tevo annto ,nm OF of i seoonle ot selotdd ted foot eteups taq owt to eno ‘To a) |) #8 yal coewted neal ,eterne ows done ,seigres DeneeTtae: dgodR to yILisdcom a amelo heed TS bao evil OY bed a ghee beeb Gdi bas emelo evil evit yfao .8f “adoto9 a0 «seen iae iets Ve, ¢eods to yiifsiron a .test siagps orf at oavel ida elssii betel est tteqxe notes. xd bedrele ps io tet em: edayo sodgentod end oxeo afdd mI sMoode ovitan edd nedd ae atatiw yiteon ,amefs Pedtate the) to dheo tog SO bovonet 3 ig aniato grtatemat eid to tod wootdaaty Tests: nileowr sont | @ ,yaosb to segade suolaav ab $£0 Sue ev ite ane cemns mortality of 69 per cent. Many of the rotting clams had grown as much as the live ones, indicating that death occurred pro- gressively throughout the summer. The new growth was very dis- tinct on these stunted, thick-shelled transplanted clams. Mortalities such as I have been describing apparently were quite general in Plum Island Sound. Areas of Low lortality, 1949 There were also areas in Plum Island Sound notable for their lack of mortality. One of these, on Dole's Island at the mouth of the Parker River, is less than half a mile from Hale's Cove, Bight two-square-foot samples contained 273 live and only 9 dead clams on July 28, and general inspecting in October and lovember indicated little or no increase. This small mortality could have resulted from injuries by diggers that worked there during the summer. Other mortality-free areas were found two miles farther up the Parker River, in the l'errimack River and in Black Water Creek, a tributary to Hampton River, New Hampshire. Past lortalities at or near Plum Island Sound This clam mortality is not a strange new catastrophe. It has occurred before. Dr. Galtsoff, of this Service (Unpublished report), examined the Hale's Cove area in 1946, and his descrip- tion of rotting clams would do as well for 1949, One square foot sample had 12 live and 35 dead clams. A mass mortality at Essex in 1914 was described by H.-W. Nightingale (U.S. Bureau of Fisheries Economic Circular 16, 1915) and many old clam diggers along the coast can recall years when they found clams rotting in the flats. Clam Mortalities in Other Areas Mass mortalities have occurred over extensive and wide- spread areas along the Atlantic Coast in recent years. Biolo- gists up and down the coast have witnessed them in Canada in 1932, in various isolated spots in Maine in 1949, and over the last few years in Connecticut, New York, and New Jersey. Possible Causes of Mortality So far, we have not determined the cause of the mortality. About all we can do at present is to narrow the possible causes down to a few of the most likely. There is good evidence that the clam mortality was not 32 Go BAAR IES AO ahs nay “gtworty bed emolo antévor orld te yack eines. “org Sett.90 djeeb dadt gataes thas \eoto eve wtih yxsv cov dewoun wen edT .tomave oft dvodgeondd ¥ , “penal bed nalqeastd baller ano fat Podiude seer! is eToW ei débone galdisoeeh need aved I as Woue rod i tage | ebouo2? baalal molt nt Lexeneg | gtedid rol aldaton bave® Baatel mul cil akon’ oats ere. oy errom old ge bapled e*afod mo ,osent to and »tittadson ~evo0 etefal sort ry B ttad sada eeel of uno iit £60 owen base © yino baa evif SVS benletdoo aefLoqmean Sue ea vie oa medmevo.. 5 me tedosoo aa “‘gntd seqeat fetenen Sas ,o8 vied mou ever Bigoe vétiadtom Ifeme eidT «essetonl on to efitll bod erty 3c fecesh etenis Seduyow sacs sanatt rd esoeltatat moth bed meaouak selina ows Havok etew akets oeti-giilsdtow weds ot sodaW Noel al bas sevii Nonmmiaie! edd at ,tevii teitai -otkttequell weil ,teviil motenall of ristudiagd a \ #I ,erlqortasiso wen ompmetin & dod ef yilietaom melo efat Berle lie rqe). eoivies effd To giloagfed .s0 .onoted Detanag eqitoseb afd, bra ,Ob0L nt mers oyod s'elal eid beniwexe (Oa) etaupe off .8h0f 10% Siow ea ob blvow anelo autivor ac eomelo baeb 86 Bae evil Sf Aad. ecemee iii oW sii ut bedigoaeh saw BIOL at xeaed te 4d hiataom econ «at asivonxt) olmonood seltedel® to. yaoi . ae) : ae “Efsoox 99 dagoo odd giols etongif mato Ee qos Sora setalt aid mI gaissos amalo bneot yes nodw Beor, -obiw bre avi enodxe revo berrmudoo evkd sottifesiorn ean “Ofol¢g ,sinsy daeoet mt Jeeod oldaslté odd nicole seeue tae ') Gf abene> of modtd beoauentiw ovat gesoo aid mwob Sino yene ‘tteve Srna ,Gdef mt onfeil at etogea bejstost sroitey: “eYeatet well hia .wtoY wet ,veotvoenm? al etaoy vi iflessol 2 os ; b2O4 eftiladton ot to seuso eld bentinxadeh dou svat ew .aal od mi Beunen oldiancq ery wortsd od ak tnesenq ta of sao ow Ifa dodA), a eVlevll daom add to wet 2 o¢ rol oe) i, ved Jon saw ysifotrou malo of2 deds epnebive boon al ered? | RS caused by high temperatures alone. The summer of 1949 was one of the warmest on record, if we take Boston records as a measure; but 1946, when Galtsoff found rotting clams, was an unusually cool summer. The wide range in per cent mortality on adjoining flats in Plum Island Sound is also evidence against the effect of temperature. The mortality apparently was not caused by the condition of the soil. Nightingale believed that the Essex mortality of 1914 was caused by decaying plant material, but we found no evi- dence of this. Rotting clams were found in soils ranging from loose clean sand to firm sandy mud and relatively soft mud. Furthermore, clams in the Merrimack River were doing well in black mud over masses of plant material much like those deseribed by Nightingale. There was no indication of smothering. Predation by horseshoe crabs, green crabs, boring snails, and birds may be the principal cause of the clam shortage. A predator usually devours its victim and does not waste it by leav- ing it to rot. However, local diggers report that green crabs nip off siphons and leave clams to die, and this is certainly a possibility. Most of the dead clams found were so far decayed that no injury could be seen, but we have found a few clams with injured siphons. A few weeks ago we found some interesting variations in mortality of planted clams in experimental plots set out primar- ily to test methods of predator control. In two plots not pro- tected from green crabs, the mortality was 24 per cent, while there was no mortality in a plot covered by heavy gauge one inch mesh chicken wire only thirty feet away. It seems hard to believe that the extensive mortality of 1949 and the various cases reported for other years could all be caused by injuries from predators, but it is a possibility worth further investigation. The other possibility seems to be that some disease is kill- ing the clams. Diseases have been described in oysters and in practically every organism that has been thoroughly investigated, so it would be logical to assume that clams have diseases alS0-e This possibility is being investigated by bacteriological and histological work at Newburyport. 35 he a CRE oe My Care aati wee % Lait th eno eaw CLeL to tommen ett .orots. sae nod yetveson £ 2s chioser movant wlet ov TL ,brooer fo | yilsuesnu oe saw ,6maL> anisvdos beusot ttostilad nedw. gaintoi ba no gi tfadton neo toq at eanet ebiw etl .%6 tootte od tentsas eonebive otfe ef bauo® Saale 4a m eo RA molitinos eis we beenea Jon esv yi? aotaqas tiladton @ to yéiledtom xeced odd gadd.bevelied efanatiduli eftou @ -#ive on Davot ew dud .ialtedam tineiq ankyaoeb eo okt aa mort gtignat effoe. al bast erew amalo gnttdoH galkd? » Draws # toa ylovitdeles Sus bim ybuse wekt of base asek nt ffew gntob stew vevti Josminiel edd at emato _orroult bedixeceb esoid eXtt doum falsvotem Inala to Bosenm tevo’ = snattensome to moliaotint on esy stedT sol eankine geilons gsninod ,edato neetg ,edartd eodeserod yd no fdabe A g@asd tole m2 fo oft }o eauso Lsqloning sd ed yan ef veel yd jt etesw Jon secd bis mitotyv att BtvOveb yifaver edaxo noety dedt ttcoces etemalhb Iaool .xevowol .260% Off 8 ® Yinlaizeo ef elds Sane orb. Gt amsfo sveel bas snoighe ¥ beysoeh tet os exew bawot emefo beeb end ‘lo Jaoll . yak ike melo wel 2 bawet eved ew tad ,mees of bivoo ytwtat setorigia betutiad mf anolietiev gaiteeteint emote bairot ew one oleow wet y “—tamtag suo toe stolq L[adwemiaeqxe ai onsio bhedausia to bd “our gon agolq owt at sLoatmoa tovnberq to ebodven teed | eftiw ,dneo tq SS eaw yoRLadtom oid gta 72 nIe"tD nowt @ eric AaB? yvaod yd bhesevoo Jolla a al ytilataom om Bat eYawea toot .viatds vino orfiw neato doe aie. to ytiiniton evinaedxe edt gadd evelfled of Saad ensee a fis bluoo etasy teddo toil hetaoqet esesss avoitay etd Dae yitfidtaeog es al 32 god ,etodabete mort sefausial vd Seam olsenitsoval told ah a wIItxn at sane ih estos Jadf ed of eweee yIfildiaseq tsiio & Pe mf hoa stedevo at bedigoseb aetd ova esarentc .eamels er eheventidcovnt pidguo ten $ need sed gadd melnanto yrove er lagks eoelo eéaroeth eved emafo dadd omsase of frotnol ac aah bis [eotsolotsodoad yd Hbotanigeeaval anied ef yilittdlee g Progen erall da olerow facta oe The Hard Clam (Quahaug) Program Louis D. Stringer U. S. Fish and Wildlife Service Kinston, Rhode Island Biological studies on the quahaug were begun in Rhode Island, with preliminary investigations on larvae, growth, and effects of types of gear, in 1949 and have been outlined by Ir. Glud at a previous meeting of this group. Preliminary outlining and plan- ning of a productivity study, similar to that already begun on soft clams, was started in the winter of 1949-50. The objectives of the program are as follows: 1. To determine the physical and biological condi- tions necessary to maintain an area at maximum production over a long period or to restore a depleted area. 2. To determine if an understanding of any of these conditions can be utilized to maintain production or overcome depletion. 3. To develop methods which may be used by other conservation egencies to attack problems of quahaugs in their own localities. Rhode Island was selected as the location for these studies of quahaugs after extensive contact with members of the industry. Two coastal surveys were made from liaine to Florida. Dealers and fishermen were interviewed and problems of the industry dis- cussed. Rhode Island was finally selected as the central area and permanent headquarters for hard clam research were established, Rhode Island offered four inducements which influenced our deci- sion: 1. The area is highly productive and has an in- tensive quahaug fishery. 2. The productive areas are small enough to be easily and intensively studied and for the most part are sheltered for maximum working efficiency. 3. The Narragansett Marine Laboratory extended the use of research facilities, office and laboratory space and a vessel, and is con- ducting cooperative studies. 4, The proximity to the other Clam Investigations units at Newburyport, l.assachusetts, and Booth- bay Harbor, Maine, permits more frequent meetings 34 ani eee a aeoed ) Pll oolvre otLLbie bie deli of “v! Peer ebortA | esoden tt na Ar ‘heiaket ehodil at avged stow siecle eit no ah hie tantonte B2eotte bas idiom qoavisl no anol daniseevnt Vaeakmes 98 bald. wad ve “ore t iro treed ever Bria GSGL al yasen. ‘to | pieigq Dua salalltwo yuedinifers .avetn als To: Sctdears BuO RO quged yhsetie gadt of teilmie yybude yalvitoubouy a. sCA~OHOL t© dotaiw eis ml Betiate) gow «om rewolfoY en ons omen ect to wevbtootde wtdir09 fsolgofotd Sas feoleydg odd entmistebh of . sites te sete ta nintdian ot yaseesooa encld | Doses od tO Dolteq aaof @ seve noltoubow . ‘ 2048 Sotetqeb to "Ha ‘lo gathnetetebau ne tl eniueedeb of ‘tlainiem of Desifitdyv ed ago anvkilbaco seid, tolselqeh emootevo 10 nolsovborg tedijo yi bean ed yam dotdw ehoddom qofeveb of to: anefdow Aoetin of rihinganrs, wf aolimvioaneo etalIlioool nwo tied? af anuedsup Boldhute osett tok nokianef edi em Hetoolon caw Brefal aYtdcubal oid to avedmenm dd tv Jortnoo evianesixe totte ag anslas® .sbinol™ o¢ enial mort ebam eter svrovene rape *elDh yadeubal ed? to ameldorwm has bewotyicey at efiew tremted asin Laidaeso edt en beloolea y{Lontl sew Soelel ebont be ) beeltidadas etew derneest malo Has cot enodtauphasd Semone a “feb tivo heonen(Yal doldw ad remoosbal me heretic baalet: ~sl an aod daa evidovbow. efaakd ef gore edT 2.2L sVtatelt nuedteup ovioned ed of davone Lfene ete anode ovitovbous of od tol bos Dbotbhbide ylovbenedal fom’! vit eee Hiidsow mvmixen il betes fede Sto Jno te0n atenoeloltie Bebe poe yroteiodad enivall dtoenanenteil oft bre eoltto ,eeliifiost doteees to eeu ade etos al bra * Lanter a Doe eonds Ytoteuocal -eethudn evivared yoo aot town anotdaghdaoved sat aacido okt ‘od yiinixor eat “tool Dim idenulassos« erogyuadwed ga etian agattesn dnenpert ena ad Enersey (onisit ~todael yad of investigation personnel for exchange of ideas and for more efficient administration. Greenwich Bay was selected as the outdoor laboratory for the productivity studies. The bay is located on the western side of tarragansett Bay about thirteen miles from the ocean. The total area is approximately 2700 acres, and maximum depths range from 10 to 25 feet at flood tide. For many years Greenwich Bay has been one of the best quahaug-producing areas in the State and supports about 20 full- time bull-rake and tong fishermen. During the summer this num- ber is more than doubled. Eight shellfish dealers are located around the bay, but one dealer handles more than three quarters of the catch. The first survey of Greenwich Bay was begun June 12; (1) to study the nature of the bottom and (2) the numerical and size distribution of quahaugs. A grid of stations 600 feet apart was laid down over the erea. Samples were taken at these sta- tions with a construction type clam-shell bucket. The bottom material was screened and the quahaugs counted and measured. This survey will be repeated again in September, and in each succeeding spring and fall for at least two more years. From these repeated surveys we hope to be able to estimate the rate at which quahaugs are being removed by the fishery and the rate at which they are being replaced by natural spawning. If we are successful in developing our estimate, our next step will be to determine the maximum annual removal coincident with sus- tained production. Preliminary analysis of the survey data showed the bay to be divided roughly in half by two types of bottom. The western half is predominantly sticky mid, and the eastern half princi- pally sand, with small areas of shell mixed with sand. Approxi- mately two-thirds of the bay appears to be producing quahaugs. Most of the small (under legal size) quahaugs are concentrated in the western part. "Neck" size clams are found in patches all over the bay, while "large" quahaugs are located predominantly in the eastern part. One of the outstanding preliminary obser- vation of the survey is the irregularity of distribution of the clams. The centers of heavy concentration were small in area and widely scattered over the bay. This confirms evidence we have obtained from interviewing fishermen, and is probably char- acteristic for most quahaug-producing areas of Narragansett Bay. Studies were begun in July to determine the possible rela- tion of tidal currents to the distribution, setting and survival of larval quahaug. ‘ie were interested in knowing whether the populations in Greenwich Bay were self-sustaining, or if larvae could be brought in from other closely adjacent areas of Narra- gansett Bay. Sheet-metal crosses were supported at different depths from small cork floats to determine the direction and 35 iy a e@BE Ro anredoxe xol Lontoaved noksantt Pec Hn PK FF sdoltonialninbe dnetoltie et \ edt sol yrojatodal sacbine. ef) as Setdelen caw % | to ehie nteteow ond no badeool af vad ont’ .velbinie pha fatot eiT ..ns0%0 ofd mand polinm neetuict dnoda yatl ar “Mort eyted adtqed mumixer bie ,eenoe OOTS yledamixnonqea ! mina thi? boolt da Jaot ! jeed of? to onc meod ead val dolwiees) ereey yaar 4O8 “[{s} Cl juods eftoqque bak esats eld al eeeta antoubouys “mun eldd sommen add prittud .nemote lt anot bas mlere Heisool or oveleab delliferte iinil .beldwob ned? ot (£) ¢Sl excl. mened aay Yad dotwnsesd Yo yowsss Jseatt osle Dae Laoltemen odd (8) fae aoditod att to exten ede Janqe teet O00 smoliate to bian A .onitedeup’ to moltis cate ecerld Js meet etow aelguec sees oft tove awob Bas motdiod eiT .texronud Iloda-nsfo eqyd aoltoutieaos 2 datw, etossem hue betnuos epuadayp att baa benes se ew Dae fose nf Bae .tedmedaee al miane betasqer ed ifin yevTnee Morr .eaney oom ows Janel Je tol Lfct bos 4niaqe golbe egai edd etanidise od sida od of egal ow cveveqme holseqet ee giant oi) Bas yteiell ede yd bevomer anied ovs envadegp dole ew It .nataweces Lotidan vd hevalaet anied oss odd deme rn ifiw qgete dxon two ,odanidee two antaoLeveb al foleesooue - “gue djiftw dneblontoo fsvonet Lavauw meonlxam edd enlimtedeb o otok FOuBO mg ) oJ ysd ect? bowors. adab yoviwe sad to sleyleane yoni fee ivetcow oT modtod’ 26 Beqyt ows vd tied at vidswor Hebe “loning Ife arejace edt baa be ytokbie yilinentnobed sixorgq’ .-fmse diivw bexiw {fede to sagas fame dulw (Saag | etgvedsup aaioubow ed of aneequa tad ety Yo abtldeeowd | in Detatinesnos eta egusdaup (aste fLanel wobnu) Iisa end © ‘(ie eerioteq at brusot ete analo oxte "vost" ating cteseew ¢€ YLfsaantmobesn hetaool oto equadewp “ogaal” olLide .yad eddie eteedo yuantloifesr: piliaadetya edd to eno ,oeeq ntetese cee eid 20 moliudindelh Yo ytlaskiipewsi ond ol yevine edd tome aexs il LfLare ovrew moltantmesnae iyvaedt to etedneo oft) ial ew eotebive saaltnos slit syad end seve heredtsce ¢gieb “teno yidedotq ei fra ,nemtedelt nelwelvretal most beatedd¢ ayaa vieensgatis4 io sretm galowhouqencedtaup Jeow tol oltar “OLed eldinaog edt ontnteded of Leb > anped \atow belhot gy favivewe Dos natttee ,aoleudiatetb edd of eddetine Labia to ely teitety gitwont st heirzenetink emew ey ~ouecdeup Leaves eavael if ao .ydiatatcve-ifer, axnev yal dotwases) wl enol 3s Lue “atte to caets duesetba ylocolo ixido mort al saguord ed, TmerTith Je bhetroggeve onew deogotd ind omedools, wyad a i bus nokiosslh od eninweieb od steoll tao Lame mort edad ag ; rate of flow of the water at different levels. These were fol- lowed for entire tidal cycles, and the movements plotted on charts of the area. These experiments are not completed and no results can be reported at this time. Plankton samples are being taken three times a week at two locations in the bay to study occurrence of larvae. A heavy Spawning apparently occurred in late June, but only a small nunm- ber of larvae have been found since that time. An interview system has been started on Greenwich Bay to estimate the extent of removal by the commercial fishery. To obtain maximum accuracy, we question the men on the fishing ground as to their catch, hours worked, and any information they may be able to offer on seasonal aspects and trends of the fishery. Experiments are planned for the near future to determine the feasibility of "farming" quahaugs. From these we expect to obtain information on the most favorable type of bottom, best patterns of tide or current, and the effects of crowding on the growth of clams of various sizes. It is too early in the Investigation of quahaugs to have more than preliminary results. Only since lay, 1950, have we had the minimum required staff and equipment necessary to conduct our program. At present we can simply outline our operational techniques, and state what information we expect to gain from these studies. This is as follows: 1. An estimate of the expected annual yield at present fishing levels. 2. The best removal for maximum yield over a long period, 3. The conditions of life history and ecology which influence production. 4, Basic knowledge of farming methods. In addition to the Rhode Island studies, cooperative and supplemental projects are being conducted in other localities. Dr. V. L. Loosanoff, Director of the U. S. Biological Labora- tory at Milford, Connecticut, is directing his efforts toward laboratory culture of clams and is assisting in the identifica- tion of larval stages of common mollusks by preparing photomi- crographs and microscope slides for distribution to workers throughout the investigation. He has successfully reared large numbers of quahaug larvae past setting size, and has supplied them to investigators in several areas for experimental planting. Dr. Thurlow Nelson of Rutgers University is directing grad- uate students in a continuation of his 1949 program, devoted to the study of food organisms and the problem of obtaining seed from natural reproduction. Dr. H. Haskin is conducting studies 36 Las | sc cienaht ani Prneet ates tot Beove [stoves nf erolepiiaeval: ba ie otow ‘adie nea sbaeneeate i doe te . m0 bediolq etaetevoen ed Bug. ceoleyo fads h fas babies cuba toe: ch atneniteqxe exadT St ve tmhd Bide te bedtoqer ows ts doew 2 serts egait moves anted ete witones gyged A. .esvael to eonetius90 yhute of yad ond nut em ‘emu {fem © yino tnd ,onw esol mt betmeoo ylimeteqqe +oml? tad? corte bovot need svsd env “og a dofwnees) no beinete need ead osaye wetvaedsat oT tenalt [slLoxemmoo edd yd Isvowo+s to tnedxe edd “gads eft end mo mem ett coljeeup ow ,yomtuoos mana boca t roliamrotal yar fae .baliow savor ioda9 sted? of ua Bi io abriowd Bae edneqag I[snoaree no tot'to of efda’ ed 20 ot otntwt seon ord tor, boanziq ete sinomk reqxt 4 iy iat eceds? mort . ex nuarigip Nort bmetet” to iifidtese? ext to ogy? efdenovat taom eid. mo cokdamroInt misddo Stee” lo efootie oft iap ,inotivo-to ebit lo entetteq ¢ ol »sesle evolesy to emafe To ddwoan edd Ao’ eva of eguanisop to moltanizeoval «ii at yfane 06% al ow ovad ,OcCL ,yei sonis ind ,adiueet yieninifesw oaae goubnan of yisasseen dnemqinvoe ban Thase Sorlepet riembctet . fanoliateqo two omlf{ivo yiqmie aso ow tneetetq JA +118 29" moxt nian oF Joonxe ew pire janw etate His awolfot ea ef eld? 48 ta blety fanseu pesesers oid Io etomiseo nA 4 »tfevel saldelt. tnoeroxg 8 tevo Blely mumixan tot favomert deod edt <8)" sholteq srol vaeloces Bas ytod ats Oth Yo saolttoacs ant PY oe stolioubowy sonerl tal’ clotidw ‘pebodder animtal to e_beiwerl ofeshi -»? baie evitedoqoos ,colbute banfel eborf edt of nottthba abi efetthisool sadio al betoubaao wifted eae atootore Lejnoteky ‘eamodal {gotgofold .& .U ait) Yo wodoorld .Ytonpeool od. eve ‘Hiewod adsotte etd sattourth ef piu lsoorsd broil lst das BOLE Mes. orld at gaiteleee al Ban: enatlo To ed fue ¥ tO TATE eimoteiq anttaqesc yd edeutlom normoo to renste faveet 20" | Bteshtow of nod ud kent 2 2B sot gebiie eqoozototm bine eee eguel beteox ylf(rrterooove eed oh. «moldanivecval edd Bwrodge betiqque sed hoe ,este naltieer deaq sorrel nusdaup “lo a Tee at ¢ttetovial otondan do route wo Lerent? 5 Foveh cnbegcrng GOL eld to noldeuatinos # af stnebata’ , hese patatsido to mefdorg ef? bas amatiagre boot to yome “eelbuge anivoubaos ef mixes uy ettotitoubongent ashes at on the growth of clams of various ages, the seasonal increase in the size of meats, and the effects of predators on seed clams, Dr. Mie Carriker is investigating pelagic bivalve larvae to es- tablish criteria to differentiate the larval stages of quahaugs from those of other mollusks, Dr. Charles J. Fish, Director of the Narragansett Marine Laboratory is conducting an overall ecological survey of Narra- gansett Bay, placing special emphasis on the quahaug populations, Dr. Walter A. Chipman, of the Fish and Wildlife Service Laboratory at Beaufort, North Carolina, is conducting a study of the basic food materials of clams, employing newly developed radio-active tracer techniques. About 1100 hard clams have been planted in Maryland in co- operation with the Maryland Department of Research and Education for growth and survival studies in this area. Another smaller planting in the Beaufort area has been made by Dr. Chestnut of the Institute of Fisheries Research of North Carolina. 37 ah eeeetent Lencease ot tone ene evoltsy to anefs to dtwory r eemaio been ao etot $6 etostte edd | “aainent 16" . a0 of eavintl evfavid o! asfieg anise saatieove trB9. Bgunisup ‘to sonedte ak ens otalinerettib of ree ‘ x 8. eetout fom tedto yi ‘entsat! sdcamemene oft lo sotoedic SVB TAT Oe Saoldanijeoval ,bevetxe yIrento tenon enndy: 9 e*%edeaw teqeeb otal wollartes moti atneriovom yino wade od Bbedtede evan, ot bovelfed ef etal mt ‘wireciatt offaoe son ts off .S86L mt Goalel drew .dM mo treeed .d4 to mod ed? ebsfont of Bebrotxe nooe arow ebagotp gilaberh Laqke tines ehisleol tneted ,21 bas sevth fodesvote edt coowled tteledos ,ideil ytev ssw ents edd va oon at seg) 50 . oHosiste enotvinoliibonm saclay xo eopbenh tere7e 10 aod wo i Latte orem ote co .tian 0 bred ‘aaridio ‘ gieem eid to ebie "ebid dde" od? da nazomd af Jade ao | bt meewted .ebase Baa yelo bied ets amosiod eft ,ams . pmtotted edt ,aleeto esedt to ebla “sbid Looft” end no: @Ad to bodamlg teseyo ,secy? bum Jtoe yey bas Jtoe on eayo nooo to eqmufo ¢qind .idgin tevo tecqqasth Iftw ogee s Ve : seoteds Havok ¢ “nod ,bnalel gaoe to ebnvory notevo ont bel mse ton ev ad «ceqy? theta ebufont ton neo om ,bnafel ebodh to: 4# neolgmas. TS. to neinee Jeutt oft bedoolfoo Ttoasf{ad Lust « od to yerane @ goiteam elidw alnwoed al emotiod mort: “eyo tol emse1ts baa eeero ciciues naisiitiae rot. sels es’,eetor bLleli ef? mort ,bottissalo etew esedT .onti (8) ,ebow yaiolita fae ebow bund-semiiuo. sojezo mt eldadhi fre ,.ebem yaoltie bos bree one , bum Boe boee--oldadive yieme elu toe yew bas ber tion ,hane galdtide ,base--oldes igen, eovitdouhorqay yfteom etew amotiod am to Bolten stoadlpad aid yd eloyisns Laotnedoom qienlnt Ler ed @S@L mt aofigmas siotoof ened? to aL mo pham eew, (£), feewted noldafes omoe woe of bemeee evodl .doxedigas (wetemelb af ,mm G00, aed seel sofotiugg)—yalo to sam sttodtod edt to soonbied 8 t e beew al dooge pilatbhino om ,deluod? yt. hodtem tedeed edd ial mt bis ‘od srege anteneqalh om one totvam olfnagio edd sys fsotnadoeli simet edd mot) velo bars tile end to noltatseg mort? .baaa.to eebeya evoinay offs etdataqee of besoqgque ef ef saw boddem stiefwolT ¢d sleyfane faolnadoell .yelo bane 7g, etdd al ,eselqmea alaroed Th Ife no tetiaw end yo O€CL miu , saotiod alptoed esedt ‘lo eleyfane Leotnsdoen eit ,eeltes tame tnesenq yelo to. davoms edd moowded noldeLorioo Ww wode don | sorvifyo ietago sot motgod edd to ytliidadiveg enme eG eV odd ot aban sew eleytlane Leolfastoan beliateb evo A 4 Halen ,eelques omse cag? to 8 ao yrodmundel sitoe Tose relciine etd to oon'T trons anleteqalbd 2 bas bodidem etieqiq afdativs edd mot? .onm Ore baee To eno. bus bom Bbied edd momen wet oT. .amotitod aivdedioens co Bem dloe edd mort + base .eme Daten itteod wid ,sosorae 8 edd to azale oat tadd Bewer eele ti ahotsen citeylo odd gd atedd doetnce weflo tewals ylotorueos aloo’ s oo yoosretyt saw Jgens nolertegelds 2 Jai Oem (sie tebtolfioo bae qefo jile to davommige holnh ‘the moot bat colttes dati end al eefomse eeceds Lfa ta weEtO00 AL acosvo! ovitourberyay mow? etew boa enact, oro Mee saw eofoarne siotdod GR to selves bacoee es yrediunt efdd sioede dneostha mee. bes cbavory pateubow sedeyo oval mowt Detoeks ~SIV ,Oaely" Rc yrostel vet nt neded etenw seen) | Veer yod mae (f}. ea beavers yrow ssedT. »,fECL bne OFCL Hf aintoed Bas ae ($) bas fer dios Sue , base . bem bredeeedSnuom acitogboug aed eben ttoe yrov Sas Sum dtoa ,onae patitide--emotiod gatom &S Of the oyster producing grounds, the hard mud type was rep-= resented by only one sample from ebb-tide side of Jointer Creek, near where it joins Deep Creek. This is near Brunswick, Georgia. Sandy samples were collected as follows: 2 from the Patuxent River in Maryland; 2 from Delaware Bay in Outer Deep water and near Egg Island Bar; and 1 from south side of York River, Vir- ginia, Sandy mud samples: 2 in Patuxent River, Md.; 1 from Piankatank River, Va.,; and 2 from Niles' grounds in Lower:lMob- jack Bay, Va.; and 1 from Inner Deep Water in Delaware Bay, N.J. Soft mud bottom samples were from: 1 from Solomon's Island Har- bor, Md.;l each from Miles and Darlings! grounds in upper Mob- jack Bay; 1 from Piankatank River; 1 south side of James River on Nansemond Ridge, Va.; and 1 from a ground off kenney's Point in liaurice River Cove section of Delaware Bay, N. J. Samples of the non-productive or barren bottoms were: Shift- ing sand type: 1 sample each from gg Island Bar, Delaware Bay; the bar at mouth of: Patuxent River, NMd.; and from Jointer Creek, Georgia. Sandy mud, 1 from upper liobjack Bay, Va. Soft mud type: 1 from Back Creek, near Solomon's Island, and 1 from Solo- mon's Island Harbor. Four samples of the very soft bottoms: 1 each from the channel into Maurice River, N. J.; the channel of North River, Vas; off Barrel Point on south side of James River, Virginia: and on flood tide side of Jointer Creek, Georgia. The mechanical analysis, using the pipette method and on undried samples, was made on these 28 samples. The results con- firmed, with two exceptions, those obtained from the first se= ries, that is: there was no correlation between the clay con- tent and the suitability of the bottom for growing oysters. The exceptions were the hard mud from the ebb tide side of Jointer Creek, Georgia, where oysters were growing, and the very soft mid from the flood tide side of the same creek and where no oys- ters were growing. Both samples were taken with 50 feet of each other. liechanical analysis showed that there was very little difference in the amount of sand or in the colloidal clay. We had this checked by the U. S. Bureau of Soils which ran addi- tional tests. The only difference it could find between these two samples was in the amount of organic matter. It stated that both samples were of the very soft muck type and unstable. ie had the U. S. Bureau of Public Roads test these two samples. It reported that both samples represented colloidal clay soils of very unstable variety. This lack of stability, as shown by the shrinkage test, was "caused by the presence of some highly porous material, possibly organic matter." Next we took these two Georgia samples to the petrological division of the U. S&S. Geological Survey. It found that the part designated as clay in both samples was composed mainly of dia- toms and with a size several times greater than true clay par- ticles. But the estimate of clay by mechanical analysis is based 44 ox paw eqzd bom bret en? sbnarores; Ve ew10 tedatot oe enie abhi sdde monk: efqmae Peed ylolvenwnd wen at std? weer qeot antol. | ittiexited edd mort 2 rewollot ag DedeslLoo ovew Bolan Dee sedew geod tela mt ved enawelod mort S ybagtyraN: “tiv cevih Mac¥Y to eble diévos mont f hos ped baslel mort Lo ¢eDi.,tevlh toexuted al & ssoiqnas ‘bum vhae woll-tewol nt ebiyvorn "sell mort baw +. .aV 4 TeV obo ,gek otewefed af sode\! ceed renal at | I Sas :.8V 4 ~5nT! *baefel efmomoloe wort I imowtt etew aofamee modttod’ wo rocqe at shnvoty regal fasd bas seLlt mort tone tes ‘tovll sens to ebte divuoa f£ ;evlf anatadneld mot = it inted e'yennel to basors as mov I har peal ,ogblil ba ob 4% gyed erawalec to nolioes evo) toviil eon! -Stidé sete pee 0 sutsouboms rae to eefqnu :yad anewel aT bits ane mott dome ofqnaa Seanen ~deond aodmtol moti bun tedl ,tevlAl gnoxedal ‘to adnan ta tad Dum Ytoe. .aV ,.vai foal do. teqqy motl £ , bun ybaaed Gam eoloe mort [ bona .boelel o etnonotog xeon toon) Nos moxt ft : tanodtod slow ytev ey To eakqnas avo% .todaall & | fornado oft 4h sit etevlA eotdmatl otal Lonneds eng mort eomst to eble dtwuor oo tniod Loriwd tho peeV ytovid dda Bintead .Meet) tetalol to ebisa ebi? booft ao Bae Stalyatv: no Die Dodson etveqta ed? nalew .etoytene Le0lnaioon “oo edfveet off .eelqnac 88 erorid mo obam saw (eelquae | soe Jest? ond mont bentasds oeatt ,saolsqeoxe Owe dt lw “ton yelo end meewsed notiafenics on eaw onsdd set Jadd | oil ,etotevo antwo TO mottiod wid Yo yililtdsiivs eat? Ba “ofatol to ehle ebfd dde odd mort hum Hae end orew eno. wioke yiov edt bon yontvorta etow atefero otsiw alndoeday “eyo on eteriw bre Yoox omee ont to eble eBl3 poolt odd a9 Hose to goot O2 dilw neved etew colquae ddo8 .natwou « elttii ytev saw ested? done bevode eleylans frotandsed ev 8 .yafo Iahltofloo sit al to baee to gavome odd al eome -ibba ast dolrw Bitot to meet .2 .U ond ud benloado ef etols neewied balt hbiyop st eone tet Ith yino etl ,ateedt® $end Sedasve +I sod dam oinenie Lo teigone ott at saw eolqn ew sefdegeny bra eqrd tou dios yrov edd Yo exer 0 Log, .foignes owd seed geod abso oiidu’ to saomd 2.0 @ Gioz yato irbloifoo betasso1qed eolfcwou ctod ‘dedd betrogs he awode ae ,vti{ldete lo toatl efiT potent efdateny ¢% Yingta emoe to eoreneta eld yw Bbeewac" ~ieet oneal "todd am olnanto eldtaadg eialtedan, & Lisbit alt ahah aes edd of aelqman algtosd ows evens wood ew doll dusq edd gandd Bnoot gl ,yavan2 Lsolgolood .2°.U end Yo ao “ih to yintem Sesoqmop esw aslqwas diod at yalo as bedana! tangy yeto ours nadd asdae tn vomid. faseves exie 3 ad tw Soa ih MF Oh Ait beend af eleyinae Lavtneroes yt yelo Lo osanides alt Cand inet iy Ta | hint \ rors on the assumption that the settling particles are spherical, The examination of the Geological Survey showed that, for these two samples, this was not true and that the percentage of clay was too high. The tests of both the Bureau of Soils and the Bureau of Public Roads were made on air dried sanples, using distilled water. No consideration was given to the various salts present and their possible effect on the physical properties of the bottoms. The organic matter may act as a protective coating on the clay particles, and thus prevent them from coagulating. In general, mechanical analysis did not tell the differ- ence between suitable and unsuitable bottoms for oyster culture. All the tests on these two Georgia samples classified them as being alike. But one was a hard clay or mud and the other was very soft mud. The difference must be in the colloidal clay par- ticles which comprised over 60 per cent of the entire sample. In the very soft mud type, each clay particle was separate and seemed to have no affinity for each other, while in the hard clay sample the colliod clay particles stuck together and co- apulated or acted as a binder to the silt and sand. We have something like the same thing in agricultural soils. ‘Some will erode easily while other soils are non-erosive. The Bureau of Soils has worked for many years on why there is this difference between certain soils. Middleton (2) and his co-workers have found that, of the chemical and physical properties, those hav- ing the greatest influence on soil erosion, were: the disper- sion ratio, the erosion ratio, the silica sesquioxide ratio and the ratio of colloid clay to the centrifuge moisture equivalent, Non-erosive agricultural soils have a dispersion ratio of 15 or less while soils which erode easily have a higher ratio. As well as mentioned later, the same ratio seems to hold true for oyster bottoms. In our discussions with various Federal agencies which con- ducted the different tests on these two Georgia samples, we learned of the tests worked out by the Bureau of Public Roads for the testing of subsoils in roadbuilding. It also found that mechanical analysis in itself told nothe ing about the physical properties of the soils. It worked out a large number of tests which have since been reduced to seven simple ones, which, taken together, show what may be expected of a soil for road construction. These tests can be made in a much shorter time than the mechanical analysis of the Bureau of Soils or that used in our laboratory. These seven tests are: mechanical analysis by the hydrometer method, lower liquid lim- it, plasticity index, shrinkage limit, shrinkage ratio, centri- fuge moisture equivalent and field moisture equivalent. From results obtained in the field and with these tests, the Bureau of Public Roads, (now known as the Public Roads Administration) 45 aie it } j A H i| efeotxorice on %2 setetivea stteains eed once pore $eend3 tot .pAdd bevode yevauc Isolaotoe) edt To’ nokta vate To epeineote: of tadd Sas eur don enw ela fat %o yee: onit bee altos ‘eo vente edd Md OF $0: edees belitieth sutew ,eefqwes beldh tte mo eben evew ehaon $neeew, silas evoltsay ead 3t nevin esv cofdereblenos of ; eit to eoldteqediq Lsoiscyda sit ao Joottes ofdiasog wi unidace evisontow ex as ton yam totter oloaano edT> se sgiidelysnoo mot weis tnoverq ems Sas ebolokiead yelo eTOltih ed? Ifed ton Std eley Lane Lao lnertoem y Sete neS a semiivg Teieyo Hot anodtad oldadivenn bas oldadinue cone wold DeLtiesslo celguse aintosd owt eserid no adeed eft Rie eaw teddo eat bra hum to yafo baad 2 sew eno tol .ottia a chy. ~tag yelo ieblol{loo edt mi od taum eomereltlib off . Dene -Olqeee etliane eft to daeo asq 08 tero beadaanos dokiw a bra elatejes 2aw afoliueq yalo tore , card bom Ptod peg baat eft at olidw .ratto dose aot yilialtie ‘om evan ‘ora “99 Bas ioldogod donde Be Lolinag yalo Holiioe ed signees eved ep .boge fas dfte era of atebald a ae betoa to peda {fiw emoe .afloe fac lpia af said? emea- — ei ff gabeis “Fo wmetm edt savyteots-non exe aflon redvo ofliw yifess eonosetith sity et etedé yw mo ereoy ynen od boltow ead Of sig rtelioweoo afd Bae (9) meotelbhb: i eflos nlatteo ee “ven ovod? ,eoliasqotg Laoleyde Deus fx trroxto ony ‘= add eo aqnah ord :omew) ~moheots Lion mo eonpnd tnt dsctoedty Siem bra ofie1, oblaolhupsse #olife afd ,oljex aoleote ort golta sineLaviuoo orsstekont enuwtitdnes aft o¢ ‘tale hilolloo: To ok to OL to oltor nolexegeth = everl eftoez fast fwol ran” ef .ofie1 teinid-s evat yliese shote doliw efios TOL ertd Dlod af essen oltet eran alt ,tedel benahsane as) orod ted. ae “AOD dati eelonegs Lanebe) anoliiy dilw anolteavoeth eo Mae ew ,eequeer atgioed ont enedd mo sdeed daotett ib edd) Bl eheofll off{dus to meorwl eft vd tao Bedtow ataeg oo? lov heim emilhbiludbsed ai eflordus to antised on? iw engeon bLod tioedl cl reba oy faotetadsen tends Savot cals silo oo Heigow sf. .eflos odd to sosvteqaw Laoiecy rhcg od dnod KEevae Oo bddubeat Head sonts oven i thle aived To etme Bs 8 Réetoeqxe ed yam tedw wods etTeidogot males ydolaw’ . Bert els if @ tl ebom ef nao eie53 sxer! piss ic Mapped baort tot flow we) Kio to npettt acid ‘Lo eteylons Laokmndoum ody aadt omtd tot tote ef oan 20%8 SBJeot nhVOs stadt eyrodeatedal suo al bee tads ea" ef “wit Otuphtl sevel Bord om nolemothyA olfd-yd eieviena Leotnade whtined goiter enadnlais glinic enetatade yxobat yorort emia in Hort sinolavions eandeton blelt Bee tiotoviape etd elon | seen odd .etdeod exold dotw hap ble Ft) edd at honkadde tant (no kéendaintobs ebrol ollivwl edt? Ba: nwendl: wie) chaineshns isi tr Gd has worked out a classification of soils for road building. ‘le requested the Bureau of Public Roads to try its subsoil tests on these two Georgia samples. These tests immediately showed a large difference between the hard clay productive bottom and the very soft unproductive bottom. As a further check, 21 other samples from the second series were tested by the Bureau of Roads and also in our laboratory. These tests for subsoils are relative easy, can be made within a comparatively short time and do not require a large or elaborate amount of equinment. I will not describe or discuss these tests, since anyone interested can obtain the procedures from the June and July 19351 issues and the February 1942 issue of Public Roads, published by the Public Roads Administration, washington, D. C. The hard clay bottom from Georgia had a dispersing ration of 8.8 while all the other samples were above 37, The erosion ration for this hard clay was 18.8, with all the others above 50. This is what would be expected and agrees with what Middle- ton (2) of the Bureau of Soils has classified as a non-erosive agriculture soil. The dispersion ratio distinguishes between the hard muds and the other types of bottoms. The plasticity index spotted the sands and the sandy muds. None of these tests seem to make any differentiation between the productive sands and sandy muds, and the unproductive shifting sand or sandy mid bottoms. The dispersing ratio, the lower liquid limit, plas- ticity index and field moisture equivalent seems to separate the soft productive oyster bottoms from the soft unproductive bot- toms. The erosion ratio, centrifuge moisture equivalent and field moisture equivalent may be useful to teli the very soft unproductive bottoms from the soft bottoms. Byt the chief value of the constants obtained in these tests seems to be in the re- lations existing between some of them rather than in the magni- tude of the individual constants considered separately. The relation between the lower liquid limit and four of the other test constants (plasticity index, shrinkage limit, centri- fuge moisture equivalent and field moisture equivalent) show these differences more clearly. But not enough sauples of hard clay or mud bottoms have been tested to make a definite statement that these differences will be found for all types of hard oyster bottoms. This work had to be discontinued in 1931 as the writer was transferred to other work in another Section of the Service. As to the other types of bottoms, the results on the 25 sanples seem to indicate that many of these subsoil tests may be useful in classifying marine bottoms into definite groups. A table has been prepared showing the range of constants as found by these various subsoil tests for these 23 samples. 46 OY wan toited' Sawer bale elise 1% notdsolt tenets: a ‘te | giget fhoedue ed tad of shack ohtcte’ TO pretud edt” \mowore ylotal bent ‘adaed eon? «valamae algtogd ab bas podtod svitovbow velo baad edd asewied eoderal tee » Teddo (8 .foote toddet 2 of «modded evltousoraaw thos 7% Sheow Oo veer ed? wa beteat eier esfroe Baoone eid HOT Vrovstodel “an ca eben od mas ors evidslex' exe eltoadue sot evaed one to onter 2 stitpet gon ob Sis omit? teode, pLevivarteqnos 2 Sevoeld so ed. soa9b ton {fiw i .dnomelupe.to davon ecae Retinoeverg etd aladdo noo beteertetal enorae eoats atase ehof vasordent ed? Bab eoree ie at col L6Of ginb Ban oauh edi Whldertdetalwbs absof olldvi edd ye hedelldne ehaoe o oh. 107 iy rh mods od velo Daal algmea rento edt {fe el tciwe S notvex pideteqelh 2 bed alnuxced m wotnonre eiT WE svods exo evorn etxentio etd Ifo djiw .6,81 as eOLDbi jadw déiw seemze bre betoernxe od “bi wow dactir el elit evinotoewion 9s oo hetlieeslo eed eflo* Yo neeanG edi: te neentod sedeluanitelbh offe+ aetereqesb edt floss equa Giioivestg eat eaguortg sifalt ted \opnd enodvod ric RAiedenoo To egret edd onlwode bevaqes mood eed efdat iy (Rofgune G8 ovedd wt sheet Itondwe (ayelmay \eawid)) (0, nme oh Based on these constants, a tentative classification has been proposed. 1. (a) Dispersion ratio below 15 wscccoeeccccecseoee hard muds (b) Dispersion ratio over 15 cesecececcecccresees SEC ZL 2. (a) Field moisture equivalent below 350, and plasticity index below 10 eeeeaeoveveeeveenenve2e2e2 0020282808202 0780878 8688 see § (bo) Field moisture equivalent over 30, and plasticity index over ou eeooovuveeceeonveeoeee2e2928 002880800878 8 88 see 4 S. (a) Shrinkage limit above 15 ssescsescocesccescoes Sandy muds (o) Shrinkage limit below 15 (generally below 10).sands 4, (a) Dispersion ratio 50-77; plasticity index 20-26; field moisture equivalent 50-45 weceseee Sott productive muds (b) Dispersion ratio 77-85; plasticity index 26-32; field moisture equivalent 44-50 ......e. soft non-productive muds (c) Dispersion ratio 35-60; field moisture equivalent 50 and up; centrifuge moisture equivalent 63 and up oo. Pub cvarecevemeenretvuncesn VERY Sort non=productive muda SUMMARY: Mechanical analysis by the two methods used is not an aid in distinguishing the type of bottoms suitable for oyster culture. There seers to be no correlation between the character and size of narticles and the consistency of the bot- tome The tests devised by the Public Roads Administration for subsoils seems to be the most promising ones available at pres- ent for telling the various tvpes of bottoms. With more sam- ples from the different types of oyster grounds in all sections of the country, it may be possible to work out an accurate basis for analysing them in the laboratory on a scientific scale. It is known that other oyster research investigators have considered various methods and tests for oyster bottoms. It is honed that the tests described in this paper may be of assistance to those who may have an opvortunity to carry further this line of research. REFERENCES fi} THOULED, J. 1907 - Precis d'analyses des Fonds sous Marins, actuels et anciens, Paris. i ft feed sat aolisoltineato svidad ned o ,odnmtenon | abun brad ee ee 8L woled older nol areata O68 secwedeoweeuswebiee on ME Seve olden mofeteqal yiloltaalg bus ,0t woled tneflavinge eretelon plots 4 ‘¢ DOC sewer orem rene henner teres maneee of wolted eRRETT yitoiseniy Daa .0& tove taelevivpe eideton ‘plete 4 & ee ee ee ee ee IS & died 78DSE Bit! YOURS seeseeveseescercuege GL ovoda slitl enedniute abare.(OL woled yilexeiney) ef wolod I tritl anatase p Dloli-,OR-OS zehirt yttoldeale yTWVeOo often molened dete ehim svitoviw4e $) +0 eaediwew CEOS ineTevbuee onde fon | biolt «SSS xeba qitotfen alg al-VT olser no heveqesg 25x ov! tovborgenon tos seevceee OG+d3) draleviupese etwieton OS tneLavinpe ead eton bLott 109-28 oldon tofomonete cos Ob Ena 6d the lav iupe enud atom egeiiadneo rqu Dae, eur evitoubo iy -nOn ?30R Ytov Ks vieeVevevenewee yee exniam et Bboeev shondem owt ond vd eleyinna Lao laedost permet: 10% eldest pe emotdog to wget add gridelogatials nil Oka eu? neevied nolialentos on od of eneda exedT .ennrine ~god old to yonesvetenco on? das eelolymac to exis Dam ogg ~~ $Y moltedtetnhsdA abaoh stidwi eft vd Bestiveb ested ont “aon de oldeliave agno gitatmworg deom edt ed of stroon) aikm mime Deport. od } sthodstod to sesqrvd seofapy edt ankifed anotioon Ito at. abAWOTS toteayo. To sored Jxorettih odd pony 16. eizss etanvoor ae duo Ntow o% eldteron ed yam JL yitnsws acta .Ofade oltisnetor a nto ytotanodel eit a ex? patey inna mk! Oven trotanidneval dorwcoees Senate aeddo datd mont a2 oo a et AE .tnodsod tetezo sot sided One ehardtom enoluav heveh tim Sonsselena Lo od teu tecag eff ng hediaagoh adveod std dealt Bee eal sind teddivi yxine of pitardtogqe ne sued Yam ow eoadd slotaas omy # at on voun aforton yealtal son ahrol ‘web senyfeneth atoonl roer scien nice to ae i's Se xTke Bro Fv: 6) (2) KIDDLETCN, H. E. 1930 - Properties of soils which influence soil erosion. U. S. Department of Agriculture Tech. Bull. 178, Washington. 48 *“soLoues Ieyjyo oj Jo esued eA eptsgno AToptm yuejysuod v pey dnoaZ 943 yo oTdwes [T seqyeoTput ey pessoT ceqemg i a t ; é SS | to-ns( 22) | HIST-E9 "9E-08 | Gy-83; 96-7S . (pT) 29° -97/1 (OO) FS-L¢ | ia ssa sreqsko | \ | } | ou-pnu yjgos Aus, 60-77 | #T8- | ee-s2 | ee-92 19-99 9LT- | eped “18. | seg | seqas £3-2! ars "| geery eee Pea saad os > i ° ‘ ek Vie feet a | Crates “3288 ca les tesa age Te = * aot paae | ok 21980 ert 7 ee NR Ce cee mee ete ea I G elnuee f sesso tie! A a é s ‘Biedeyo onebaag é ereteyo=buns ybra. ont =Disn Ybas: i eeeeson atetare é etesayo-bim stod onehtas JTIOG : @eseese SEGTEYO: on@beri tios yt38¥ =e (o#e8 wrod ayo’ - - Deaged issar 24 A Brief Report on the Texas Oyster Investigation by B. Bs Baker, Jit". Texas Game, Fish and Oyster Commission Natural production of oysters in the bays of Texas has become a thing of the past in view of the tremendous decline from 200,000 barrels produced in 1904 to about 7,000 barrels produced this past year. Cverfishing and neglect of the reefs is probably the principle factor for this decline and the es- tablishment of systems of commercial cultivation appears to be the main solution to the problen. The sheltered bays along the Texas coast provide a suit- able habitat for oyster cultivation and though the environment is in many respects dissimilar to that of the Eastern Seaboard intelligently conducted cultivation should produce marketable harvests in quantity. Since 1947 members of the staff of the Marine Laboratory, Texas Game, Fish and Oyster Commission, at Rockport have been engaged in a research program designed to secure data on growth, mortality, spawning and spatfall, enemies, and the physical environment of oysters as an aid to the determination of suit- able culture methods. As a preliminary step in this investigation, six one acre plots containing varying amounts of transplanted seed oysters were established. These plots were located to include as many variations in bottom and hydrographic conditions as possible. Periodically growth measurements, mortality rates, salinity, temperature, and spawning observations were made. Results on the whole were not favorable although in several areas the loca- tions chosen were for the purpose of determining the extent of utilization of poor quality bottom. Mortality was generally high, raging around forty per cent and in one location several plots were decimated by the oyster drill (Thais floridana flori- dana), Average growth over about a six month period amounted to approximately one-half inch increase. In 1948 two types of cultch were placed at one location, these being dry shell spread evenly over the bottom and bundles of bay brush anchored to concrete blocks. By August of that year the shell showed a catch of over two spat per shell and one year later an average catch of over one spat per shell. Due to rapid fouling by algal growth, the brush collected practically no set, however, it is believed that under more suitable condi- tions a satisfactory strike could be obtained on this type of cultch. There was little spat survival because of drill depre- dation. 50 ‘yj saeet odd asens fatevos on? dguodtie eldsrovelt Jom etew oe | nottagtteonat nom amet td a | | ee \ oath javded 6 4a ae dot we timed todey0 brea Cail eonag saxet ! ead eexeT to evad od at eteteyo to notieuborq fanud | eniiveh exobnemetd ed lo welv mi teeq end to natdd s alentted OOO, ¢uoda of BOCK at beonbonq afomed O00 £908 | ° lees act Io Joelyor bae gatdeltaev) ‘stae¢e taaq etd?” 0 uD “20 afd baa aatfloeb eld’ tct sogvost efqion ing edit qidade ad of etaonie noljavidiuo L2lonemnoo to ametays to J noma ke sheldow edd od noltufor: cg etius & ebivou dagoo eamxeT od griola aysd betedieds. at r Yrommorlvyne edd davoidt bas nolttevidiue tetayo wt da 4 beeodael ateteat ett to dard of tafLlmieetb edoeqeer eldatedtem coubotq bivode nolteavidius betoubaos. ei raonatde Titinaup al | eon eafiall edt to Tiete edt to eredmom Vael sone ttesd evad ttocdooh ga ,molselmmod tosteyo Hrs delG , sddworg mo ateh omus0c of dbomntaeb metg0% dotasaet 8 ob} feoleyiq ent Sas ,eelmene fietdaqa bum galnwaqe yy: “tive ‘to ho Mantmted of adi? of Ble ne ea stesayo to Pde: . « bods om vaiti ® eon oto xie uo} sng! sogva efdd al qats giant iter & eipteyo beer bednelqanetd Lo sinvons yaty tev ee Ueto se ebutont of boteool etew etofa esol? .bedetidad ‘yeldieecq sa enotithnod otdqnunoried bas modded nl bait» evtinties ,eeger villadsom, ei neretunsem d#worty yilaotbe fo sifueeh .ehan ovew enolsavresdo unitnwaga bas getmses to Snetxe att galetuned ef to eseg¢iue edd tot eter mecodo an ullatenes saw yihiadcod .motjod ptifeup soo Yo noksaaks fersvee noltmoel eno at bar taeo ted ydtol Sayous gr gat Bits, eusbhisgols & ) £fiab tedeyo ed? yo ‘botemtsed egow | a of basovons boitec dicom xte a duode weve ‘AdmoTy enatev, et | | ade he any font Ttflad-eno vLovemtxor notdacol ere ta bevalq etow Dikhit to cerg? owd GAOL) nt | bolbaud bas motiod a3 reve yineve beetoe Leda yb merdiod. | tend Lo tenges yo|..ukoold eterdnos' ot bevonuna dene, vad / eno Boa Siwte wy deqe ord. “evo Lo soteo » bowode [fede edd ae ‘of out .tfede seq teqe ono seve lo rofeo ogeteve ne model | qiksoldonny Detoolios dantd odd ttworg Lanta yd gabigor nite wlbnoo ofdatium etom tebe tad’ bevelled a2 ¢! tevewod 20a %o edz? eld? ao heaiatdo od bluco eltase yrds oatelios @ en vongeh Ifinh to esauesed Lavivus bivsicon Kae givet antl hia a During the season of 1948-1949 three additional seed plots were eStablished using specially constructed dredging equipment which materially reduced the cost of this operation. Mortality was somewhat less than the pre vious year, averaging around thirty per cent and the growth rate remained at about the same average. Approximately 7,000 adult oysters were placed on a sea rack in November, 1948; examination the following year showed an excessive mortality by drills and probable trespassing. Shell bag spat collectors were placed in an area of heavy spat fall during August, 1949, with counts being made every few days until early October. The average set per shell ranged as high as sixteen spat. Similar collectors are being used this season but examined on a monthly basis, the initial set aver- aged around eight per shell and at the end of three months had increased to about twenty spat, measuring up to one inch in length. Plankton analyses have been made regularly throughout the area with particular reference to the abundance and distri- bution of oyster larvae. This year emphasis is being placed upon this phase of the investigation. Straight hinge larvae have been observed as early as March and there is the possibility that Spawning may continue into November. In all bays under study ex- cept one, the spatfall appears to be adequate if not excessive although mortality rates are often high, probably due, in some instances, to the relatively high summer water temperature in shallow depths. During January of this year a survey was made, with the greatly appreciated assistance of Dr. Philip A. Butler of the U. S. Fish and Wildlife Service, of a number of reefs in eight of the bay areas. This survey showed strongly the deplorable conditions existing on many of our natural reefs as relatively few indicated capabilities of producing market oysters. After consulting with Dr. Butler, a series of recommendations were considered for the long-term objectives of this research pro- gram. The objectives adopted are as follows: 1. Further study of the environmental features is neces- sary to determine areas suitable for the cultivation of marketable oysters, together with investigation of the costs and methods for improving and expanding na- tural reefs as well as for establishing new reefs. Data on the physical and biological factors pertain- ing to oyster quality and productivity should be ob- tained. 2. It will be necessary to evaluate properly the existing and potential oyster resources. Surveys should be made of the size and location of existing reefs with analyses of their population. 5. Factors affecting oyster culture should be studied where localized problems in pollution may occur. 51 nt LO ah fe ay, ial i ian | siote roi dias bihbine suis ametnerad. ‘oeked | ay tee aniubesh botounseneo ylisioege gakeu i a {Asso waolderoqe alt) to gage) elt Beduber yila Pay “bavots gntgareve ,teey evoly ety odd medd aael a i emabe edd duoda ds bealamet ete Adwotg ent bone dnao 26g pee 8 mo beoalq otew axotayo dfiube 000,% YletemixougqA 40 8 Beworie wi)ey aniwolfol att notdanimaxe aOhel aedaovolt nl 2 earls BORE RO SY oldadorg base efiied ed td ifedton ant &¢ ‘Yveed to nots na ni besala etree etotoelfoo ssqe asd fled wet yreve obam nated adavoo dttw .@Mel pteunwA galrob let) ws besnst Lfote toq Joe ensteva edt ,tetioded yflise Litaw wi eins beet sated eta atoteelfoo tnibala vdeqce neavaxia sag reve tee [aitial oft ,eigad yiddnom » mo Senimsxe dud) aes bed adinom setdi to base eft Ja baa Lfoie oq dogo bavoes Bi mi dont eno of qu ant tvee em ,taqe Ysnews tuods of basaam tvodgwows ylaelunet eham ood av nis eeeyians cogvanl?) sav “hatel® bre eonsbauds edt of gonero'tet asfvoltdnaq ddiwie one mnoqu Gooaly anied ef efoadgms tsey etdT .cevaal totesyo F a ever eavisl sunid Jdalewé nottanttesvat edt To off at oruten eldd to sélbhbude tanolLeoxe. to tag ets ovla axrodoolfoo faq .fedelidwa’ baa ebam aeed evade Benlatdo ec tigim doldw joa Lotinestoqg eid patisoltbat mf tae eenakinalq {flere bemkt yinreqoig dawom?d enoliaool agot 10 exad este yb Yeas edt nogu ,dsdd awode evant gteb bedadu xmey vem sofidee to avetiag bas mosses eH? Aen odlmeqeneid wiewil at ss etpey oF te0ey mott bas eoalq of eoalq mont yt Hofdw usote boow Yo stelteool bas Javome edt mt eognad a . ‘bree edd egnecdo tedicol yam aaoldatego anivacviad mot tim ete gaiites to snoivevreads evieueixe ban Douatinod ae \betarta Yo eban of yon cen ovidoette Jeom edt dadt tebto at Behe mayo beee dnotoliiws to fold ouborg ered aotge: efdd af dod Yam Holiw arotos) yuan odd lo selbwte .meldotq wolom @ Bt weniue yd absm nated ote sanidtes al enctisataav ebiw edt fe ~ OL gniiies TO moektagmod seota tetto bas ett al areltow eoneulini coldw etogert dotcw vd sneent edd to eno ebtotie Bb | besiot od. yom sbaett palites Foren fad seiied Jedwomoe lo smo an benealo od yam CdCl as6y) ont. sbaetyaet al soie retaro efaeqavedd eld Yo dos seve Jee’ ex “oy dmyos. dace egetove odd ewods (Lf .gtt) saeco gaiyaagmoges | TO geod .otete ed? Lo enolget Snotetres sol Ledeaxd braly atinow sotntw boo Ifet odaf aid antash ebem etew edaean er Ge: | when the spat were generally around an inch in length. Ina few instances the figures may represent only one or two bars but most of them are averages for a number of bars for which details cannot be shown on a chart of this size. It will be noted that setting was very poor along the upper Western Shore of the Bay and in the major rivers except near their mouths. The tendency towards higher setting along the eastern side of the Bay agrees with observations of previous years. It is in accord with the findings of Dr. Nelson in Delaware Bay where he attributes the distribution of oyster larvae to the diver- sion, in the northern hemisphere, of the entering wedge of salt water along the bottom of estuaries towards the right bank as the denser water moves upstream. This diversion is a physical result of the spinning of the earth. The Potomac River and a few of the larger tributaries show a similar trend in setting. Newly planted shells usually receive a heavier set than do old shells which have become weathered and heavily coated with fouling organisms. Certain areas in Maryland whose past record indicates satisfactory setting and which possess sufficient acreages of suitable bottom have been designated as seed areas. Large plantings of shell are made annually by the State in these areas later to be transplanted to good growing bottom after re- ceiving a satisfactory act. Other bottoms of smaller acreage where moderately good sets may be exvnected are shelled lightly and the resulting catch left to mature without transplanting. Pigure 2 shows the set received in 1949 on all shell plantings of that year with the four areas designated for seed production so marked. It will be noted that the seed area in Eastern Bay failed to receive sufficient set to be utilized as seed. Also certain plantings not intended for seed production received too many spat to mature into the most desirable type of market oys- ter unless thinned by transplanting operations. In general the spat counts on planted shell were considerably higher than those made on old cultch in the same areas. Periodic exposures of experimental cultch, mostly in the form of clean oyster shells in duplicate wire bags, have been made in various parts of the Chesapeake area by the several re- search agencies. Special emphasis has been placed upon seed areas in order to indicate how better timing and placement of shells might produce higher sets. Figure 3 shows graphically the time and intensity of 1949 oyster setting upon test shells at four Maryland localities. All shells were reasonably clean ones selected from a commer- cial shell pile but were not specially washed. They were ex- posed in random positions in small chicken wire bags. Ten ran- dom inner shell faces from each bag were examined under low power binoculars after exposure. The area of each shell face is recorded and the results have been expressed as spat per day per shell inner face of a standard area of 50 em.” Parker Moore is a typical bar in the Chesapeake just above the mouth of the 54 ent .tidgnel at Ce eee etow teqe ol? an ated owt to ono ylao tresemqet yom eexontt edd eesmadant wet, Hotdiw sot eind to Aednun 2 «10k eeaateve ete mods ‘to deom tad ed. {ftw si ,osie eid? to dando 2 no mwode ed Joamso ellatehin ercHe nvedee.” teqqy edd ynofs tooq erev aew aatdtes dadd: bedom: seddyom slot ten tqeoxe arevi* tolem etd af bas qed odd Se to oble atetene edd naols gnittes tefgid sbaawot youebaed)¢ al ef-25 .e%sey ewolvetg ic enoltaviesdo difw eeotge yee) eteiw Yad etaweled al noefel .12 to egatbalt ent ditw bee ~“tevib eit of eavial teteyo Io motsudtatelb edd votudiaqdday vias to enbew galtesne ect To ,oxerqelmed atedtson edd mt: gm 68 Aned ddipit oft ebaiawod aelireutso lo modtod edd gnoin s Isoteyde a ef moletevih ali? .maevtequ eevor tesaw teaneb! 8 bas tevlh onmotol eff .détee oft to gninnics end to aime sgnisioe nt bret) vealtute « wode eoltadudiad tenisl edt Too ob madd tee telvsorl «2 evteses yfilevay ellede betnalq ylwel § dtiw betaoo yLivaed bas bereddsow emooed ovad doldw effed biopet tesq ecortw Bnalyisl ni exerts afeatred .smeliaaato an daelolitus meepeog dofttiw Das pnaliiee ytotostelzse eevaakaaee -e8070 bees eh bedenpiced need eved motiod eldatine to segeemmml eased al etete ed yd yifeunna ebem exam [Lode Yo ennttoale eae “et todle mottod galworg boon ot bedasiqenat? ed of tedel gas ensaeis telfama to emotiod tedi0 tos yaotssTeliae p : yitdglt belfede er betoecxo eof yam edee boog yLotatebom em eaniiasigqenasd syordiw otvtam of Stel doteo galdiuaes onl®! enniinsiq {fede Ife mo @del al bevisoad ter ed? awors & Oam noliouborq bese tol betengtaeb exacts wot edd nitin ssey Jedd ae You mseseed mi seta booe oft jodt Dedom od [fiw #1 . bed a Celi .beee ee heslitin ed ot toe dnololttwe eviscet ot Doliat 00% bevieset molktouboig bees tot hobnedal gon enatiasta al 100 “6¥0 Jesdtsn to éqyt efdatleesh taom ad? otek enotam of abl nf edd dsvenen al ,anoliateqo satinaiqenett yd benaltdd seein e8ods dedi tedntd eidaseblenco etew [Lone betnely mo sinuoolge Mad . .s20m8 enac eld at dotive bfo ao “ahE + edd al yf{iaom ,doliwvo [etromtioqgxe to eonueogxe sibotast | geead eved ened ettw eisotiquh at effere seteyo naelo To m "et L[anevee edt yd sox siseqezeldD wf4 10 eéaisq enoltuay ab eR Bees toqy beselg mood eet elandare Lateoga aetonesa Hem 29 tnemesetg bas animit tetted wod eteotbal of sebto at cade toratd esvboug dint ab GOL Yo ydlenodnl bas omtt oft yLinotdaota awore © eth lt) etettif{eool baslyse! quot gc effede teed moqu yaltiea aeds “Tommod & mort heloelen eero aeols yYidanoeaet erow el Leda) “xe etew youd? .hersew yilefosge ton evew dnd eltq LLotat “et tel yeged eriw medtotrio {Lowe al enotiftdeg modbnet al Bee wol ebnn Deninaxse susw sad doge mort .asost Ifede sonal me ef eost [Lele done Yo sons olf ermouxe tedta enafyoonid meme tog Yeb teq tage Bg beessigxe soed ovad ativeet edd bas bebioss el stood textual “to Of To asts betahrtades 6 to eoet tenmh fieas edt to ddwom odd evodsa tent olaeqeeedd ett al sad Leolay?d #8 Patuxent River. It is a dredging bar and is still in produc- tion. The Swash is a productive tonging bar just inside the mouth of the Patuxent River. Both of these have a relatively poor setting record although the set of 1949 is somewhat above the recent average. Holland Straits is an extensive shallow water area lying between low marshy islands which separate the Chesapeake Bay from Tangier Sound. It is about 15 miles above the Virginia line and is being used as one of the state seed areas. Seminary Bar lies in the St. Mary's River, a tributary near the mouth of the Potomac, and has produced the best sets during recent years of any of the state shell plantings. The intensity and time of setting in these four areas illustrate typical variations which may be expected among the various bars in the Chesapeake area. Seminary Bar has been planted repeatedly with shells for seed purposes during recent years. Fig. 4 shows the setting for the past five years on shells exposed in test bags. The commercial set on the state shell planting is indicated at the right. The season of setting on this bar has been rather con- sistent from year to year although the amount of set has varied. As information on the time of setting of spat and of certain fouling organisms has become available, the time of shell plant- ing has gradually been shifted until most shells have been planted just prior to the beginning of heavy spat-fall during the past two years. There is indication that this policy has resulted in a more effective utilization of the potential set shown by test shells. Extremely heavy initial setting, however, will not necessarily produce a higher commercial set due to mortality caused by overcrowding. The entire St. Mary's River comprises one of the highest setting areas in Maryland. Fig. 5 shows the 1950 set on 3 bars where shells have been planted at various times for seed production. The intensity of setting this year increased to- wards the upper portion of the River. Counts of set on scat- tered shell plantings of previous years show the same trend of increasing set upstream. Data showing a more detailed distri- bution of set over this area and over the Holland Straits seed area have been gathered, Qualitative surface plankton samples have been taken in those area where shell bags were exposed. They have shown an abundance of oyster larvae prior to and during the period when heavy setting occurs. Areas receiving little spat fall have shown few larvae present in the plankton. From a number of years of observation, it seems characteristic in the Solomons area that extremely light setting tends to be scattered over a long per- lod often extending from early June into October. In the high setting St. Mary's River seed area spawning and setting are peaked into a two to three week period. In the first instance above, many oysters retain their spawn throughout the season and into fall or sometimes into early winter, Oysters in all 55 uae ‘Me {Lite al brie ted initebuhbe a aa ie ext ebteant teat tad ant pad evidoubors o ef dam yiovitales 2 eved esetd to Atol nev dooxnied ens." o dt evods tedwemoe af OGL to dea eft dinwodd Le broven paksss a4 wofiede evianetxe me @t ettaid? SaelfoH: soyetevs Ineoee) édy oteusqes doldw shaslél ydatem wok nent hg GRERE: ROU) evods eofim @l tueda af dT «.bawoe tofgast most ved eden Dbiea otsie odd 16 O90 aa bee anted ef Ane esti atat yteatsding w ytevill elyael .32 ofd ml oehl mal ytentned ajen deod odd Deoubortg Bad bao ~oamoted add to davon! edi oi? .~agatinalq Lfone edasve o dg te Yoo Bo etaey. tases ajamenulit eset tok aeadid af yatddoe to emke Hee yee etad avoltev sf} acme mesomine ed yom dotdw sootkieltey gf . . oHaTs olaoqes odd mor alfonie dilw ¥lbotseae:t Hoinelq seed sad tA qraatmod aiivdea oft awote 5 santa .atmey tnedet gotivh sesoqaig | eft aged dset at besoqxe eilede mo suey evi? tesq oh odd Je Hheisgolibat at grt dere Lg Sforis etete efi no tee Latod “199 teddet meed ted tad aiid no antizes To noseom edt aa chateny gan Jee Lo tasome od¢t duvodife teey od tsey sort on - Nlaiqeo io bas gage to galtitea to omit oft no noltemtot -tneiq Lfedé to emis odd ,eidsiteve smooed pert ane sitnag to nant heod even affece goom {linn dbeitice need- vilaubs 1 Poet. gninuh ILat-daqe yveedi to Rainn! ged od of nolaq gent Bea tad yotfiog eld) tarid moldwolthal al eted? -2Tesy ows Jane tor Pvnoien ert to moti askitie evitoetie etom s al bedi ytovewor .nniidos Ialdint yvaei yiewetiazd .ellerie teodt, ww) od ne, Vici {alorspinos sorintel m eouboug Yilresesoen some nil bwototeve: yd bacues ‘yatta Paedatd eit to. tio soetaqnoo eovin o'yaal te ont one ott Sa | 8) MO tes O8@L. edt .ayode ¢ .gtt Saale ill at aneis Biles ) eee tol semi? suotaav tn bet antg aoed oved eflecs otodw Sam “wot Besparéal apex atid anicder Yo ytianedinl ed? .nobtoniay eta0n mo des to edasod wneviz att to molitoq teqaw odd Bae “to. Herd ewae edd woe essoy evotvord to tgntdaalq Tfota aan “) iavet Hellaveb exon eae anivods sje ymeotiaqy joo nat ore Fai ediessS boaltol eid seve bos set eldt aevo itor’ to mom sbotontag nesd ovata mt neilead moed oved yh bp rotunal¢ eos Tits evivestionp | fe awode eved yedT .bescqxe otew spad Llerla erodw sens 08 ar teodw botdeq edd galanb base od sola osvtat secdeyo to eousbaodm® nwode eved [fat dsqe offd4i2f acnivieoes eaetA .8two00 galiden YV to extpey To tedmwn e movi «aoslaala oft al daeseta oavael ‘dart seg saomofo® edt af oldatredssiade swsee th ynolsavtpes “teq gnol 4 nave boteddace od of ehoed galites ddall ylemenry: Pov ss oie Ml stedoto0d ofat sau ylioe mord galbaoidxe natto wa godin brte aolnwag 2 nets beer Sevih eiyiaM oat oon eiadan tectt ad¢ al. -.bott0eq aoow sent of owt » otal: nosses edt Auaiguoiudd owege niet wladen stetayo Uist « Ife al renner wtodatw yigae otal somitemos Yo Liat ost ae stages of spawning may be found during the summer. In the latter case, practically all oysters seem to be almost completely spawned out after the setting peak has passed and remain thin until cold weather. The areas of high setting typically are rather landlocked and with less exchange of large water masses than are the por- tions of the open bay and large rivers where sets are usually poor. Brood stock characteristically is in more densely popu- lated groups and probably is more abundant in proportion to the water volume present. Such conditions may influence the trend towards higher setting. Until more knowledge is gained of the factors controlling setting, a more complete utilization of bottoms whose record indicates favorable setting conditions coupled with retention of well populated areas of brood stock in them seems to offer the best means of increasing production of seed oysters in Maryland. 56 notaat isa Wt, § cob nare' eb Gulden aU ask raft re geonts sant neos Btedeyo mie fifames Bre beensq wer Meo gaktioe oft sir | to new ‘Heveolbusl tedidar ete Tilsolagd natives digital to enone | “tog erld o1s aeid seetan totaw egret to snianeoxe esel ¢ Tllaven ex etoe etedy erevin ental bas vad nueco etd “wqoq Yfeoenwbh etom at et ylfsolictaodoataro Mooda boost oF aoliaodosqy ai dnshoude otom al yidadorq bus eaugtg eit eotenltal yam aneliifbaos ove sdnoeseiq sunfov te Donley ef eabelwomd etom [lta .yatdvoe redid ebtawo motdasif€tin edelquoo erom # ynutddee yalffotinos axotost -enolitibtoo naititee efdbrovet aedsofbnt broset saodw emod NXootea Sood Yo saeta betelugoq ifew Yo nolinetet dit fw noltoubory anlesetoat to ansem deed edd setto of amese® shnalyret at sieteyo & 0a, | Q 45 i 15 | Re - at {vw A aS 7 ite Ge Qs - { i] eM | Cay Nusa ee I a OS aaa SET : ee ins Len pt eee nen aremnmee ng enna cena SPRT/Be oid curTcCH, AVERAGE 5 FALR IFA FIG. | CHESAPEAKE BAY ' zoe (Oita Gi 4360 2 ie ae y Dar naan SEED SI EH «| CI Be rE r re y Ist ie oo SPAT / au (FALLS STATE PLANTS, I949 SET cues ee m4 C= an JI vad * cos i] ¢ < J ry Lr a ow Cc b y i \ ; Pet's \ > ‘ ’ 7 ye ———— FARKER MmoOoRE oy; a ro | a) { | rie | c | SW ASHE & | SS Rare Le oO; a \® S| > a Se a | HOLLAND STRAITS S| ~~ mle or RS Oe eesereg ed pee) SS 2h So eee ~ a = a i aS va SEMINRRY ie ISU ese Le Tuec) ans ic Ze 3 ve = te Js A S FiG. 3 | (Sac 15 - ie I i i | MARTIN PT. | 5. i | \ | o a 25. c H See Bp =) lie ~ etal RSE HoRsesHesg ReEMD Saree — = i) ‘ Q 15 mh = : x fs a ey val 5. SEMI ARY ct. a ee | \ PESO Ty ROAR T er bare ALO | Weare Wenn aoe ey eae mA AR Es Ce er at te Ww 30 1 71k ola wes | oO 260 3 oO 206 Je Ji A S eg ii Wis Aun GU Sa ET aa vB bu: i | a | fi ‘ ; f ‘ ralhy i re pens AREA Ko i aya 3 a} i DUA Gt hee ) ve ; Z ‘ ay ne 4 trees ALND ay ( { i l j Fi * HF lerela onsen oa " ’ m . / , r x * } +; 4 ' Tt. . - : j eas ¢ ’ ¥. iW ~ ‘3 “hee , i i t : 4 * ’ vas ‘ ' : ‘ ¥ , \ rs ' i SPAT / DAY /inweR SHELL FACE SEMINARY BAR vive WF cae , LATE FALL a Us 3! ‘ 31 E SPAT / Influence of Seasoning and Position of Oyster Shells on Oyster Setting by Fred W. Sieling Department of Research and Education Solomons, Md, The settlement of oyster larvae, which is a critical phase in their life history, has been studied here and abroad for many years with somewhat conflicting results. Nelson in 1926 found in studying the spat fall of Ostrea virginica a ratio of 10:1 in favor of the underside of cultch. Hopkins (1935, 1937) found a ratio of 300:1 in favor of the underside of glass plates when working with O. lurida. Bonnot (1937) found that 0. lurida showed no preference between top and underside of collectors used. However, he qualifies this by saying that this may have been caused by turbulence created by the type of collectors used. Prytherch (1928) said that OQ. virginica set heaviest near the bottom and on the lee side of his collectors, Korringa (1940) observing 0. edulis under field conditions found that spat settled heaviest on the upper surface of his test plates. Cole and Knight Jones (1940) found similar results with glass plates immersed in test tanks where 0. edulis brood stock was kept. However, theyfound in 1949 that 0. edulis larvae set more heav- ily on the underside of cultch and that this was due to their habit of swimming upward and settling on the underside of any object under which they were trapped. They felt however, that their results, although in favor of setting of spat on the under- side of cultch, were not completely conclusive and that other factors strongly influenced the setting habits of QO. edulis. As regards the seasoning of shells, Cole and Knight Jones found that larvae set more heavily on shells which had remained uncleaned for a period of two or more weeks, and which had a film of bacteria and diatoms, than on shells which were cleaned frequently. Those shells which were heavily fouled with sessile organisms were greatly preferred by the oyster larvae over clean shells. This data is quite conclusive regarding the preference of O. edulis larvae. They found that silt was the critical fac- tor in assessing the suitability of cultch. Zobell and Allen (1955) suggested sessile organisms prefer to attach themselves to surfaces covered by a bacterial film rather than a sterile surface. Coe and Allen (1937) found that larvae of O. lurida preferred glass plates that has been used to those which were freshly cleaned. Scheer (1945) also suggests that the presence of a biological film favors the attachment of certain sessile forms. Undoubtedly many ecological factors affect these re- sults and give different answers in different geographical loca- tions. There has been no mention of any work done in the middle Chesaneake area in any of the literature and so it seemed ad- visable to make an investigation in that area. 57 todeyO to motetecd bra a gudaoeane 1 ta coneattat | gitdved teseyo mo sean } yd nalflelo .W bev aoldeenke brs dotaouel To taentceqed ob .etomoloe qnadq Leolttixe 2 ef dotdw ,osvisl teteyo to tnemelites ed? gnam 10% boowds boo eted belbute seed aan eTrodeln otll aede Bee hg Fre noelell eB Lueor gutsolLiang Jodwomos Ady iat £:0L to ofist 2 ag ea io [fet Joqs of? an cout _bavot (Véel ,8seL) salsqo Bx; wo to ebiesobay edt 36 TOV , sioda eodalq. nals Yo eblearebay edd to rove at renee te of 1a «2 dad? buso't (VOCI) sonmed «4b? délw 2 atoioelfoo ‘to ebtetebay base qody ooewd ponete OTs On | oven yem ald? derid gatyeo yd elid eolilfeup ec vtoverdl eheau ntospelloo to eqy? edd yd bedaera eoneluduyt yd becus . an edt wen taelvaed tos 02 tad? bles (83er) pp Ay (OD¢L) agalriol ,etotsel loo YG obte eof odd ia baa moe daqe tad? basso saotdtbass Phelt rebay pls 02 gotks efo2 .eetetq tect eld to eoatare teaqqu eft co eeltvacd eotalq testy ddiw edlvact aeitmie bavot (OL0L) eenol “aa stqged esw xooda boord «2 etarw exnad taet at “vaert exom.tee eavisl dant? @beL nt poli a ated od enb apw ofc 77) bas Hodfve to ehterebay odd om ¥18 to eblevebay etd no natities. boa berawar gntmmtive to ted? ,tevewod Jiet yet .Sacystt evew yorid doldw tebmm we -qobaw eft no dena To gakider to tovat al dgwottin adfpeet’ i neddo dadd bas eviawfonoe yfeteiquoo Jon otsw Sorina to @bl eitiube «Q to etident anidtoa edt boonen! tal ylaaorde etoros Serol ddatnad baa olod ,allede to yninoress od? ebtegot eh | ay benieme: bet defdw effete mo eflvaed onom Jou sevanl Jel? Dame & bad soldw bone ,aleev etom to owt to bolteq a tot benaeke bomelo etew dotdw elieds no nadt .erodeth baa alredoad 16) m, elleres ddiw beluot ylivae' ervow doinw effede eso? Lineups ieefo tevo savial toteyo afd edt bewtsiein yiteorr sr93ew smehal “taba dy ai? aatbieze 1 ovienufoneo ediup ot sisb aldT aa ae “081 [soliive add saw dfte sadt Bauot yod? .oavasl | 2} sella Bra Ifedod eodf{uo to ysliftdsitue ets uc Fee tevleenens sondén of telow emelaenro eltesos bedeonawa (ae elitote e aadd teddeat m£lt Lelaedoad a yd betevoo seosiiue att «2 to oavisl tedd bovct (Veer) noflA Ona 909 di erow doliw esod? of beav need ead tect? eotefq sealy bowre eonenety ort Jadd eteogane oele (GAOL) tooo? ny ose ak Ldeon + ia eftesee niaives to daemioedie afd etoval mitt Laat * Yo | “er ebedd Joetia etosaat Laatsoloos zane cibetdac ai e *sool Iaeotdaqetpoen snotektlb mi evewane dnetsThib evts baa hers eLbbinm edd at snob Atom gan to molinem on mood sad otenT ) «ba bemoos #2 06 Baa santatotil ett To yoo al eote, aaineg vps Aor godt md Kokdan td eoweek oun er npg 1 why These conflicting findings and the lack of evidence concern- ing the larval behavior of O. virginica led to the simple experi- ments which are now described. The first investigation was to test the efficiency of shells which were seasoned in sea water for varying periods of time before being exposed to numbers of larvae of O. virginica. Clean shells were immersed in the Patux- ent River where almost no natural set occurs for periods of 58 days, 25 days, and 9 days before being exposed in the St. Marys River where large numbers of larvae were known to be present. These exposed shella were carried over to the St. Marys River while immersed in large cans of water and placed in the seed area. At the same time clean shells were placed at random in 14 inch mesh wire bags and suspended just above the bottom in water of four to five feet in depth. These shells were exposed for seven days at the height of the setting from July 7 until July 14 (Beaven 1950) in the seed area. Unfortunately, the shells exposed for 23 days were lost as a result of tampering. How- ever, the other bags were recovered and ten shells removed from each. These shells were examined carefully under a microscope and all spat, barnacles, and bryozoa counted. Duplicate bags of shells were examined for each length of exposure so that twenty shells were examined for each length of time they were exposed. Each shell was measured as it was examined and the area in square centimeters calculated. In the results a stan- dard unit of spat per 500 sq. cm. is used in comparing the num- bers of spat setting on the different groups of shells. The results obtained are not conclusive but are suggestive. The work should be repeated and expanded another year as the abrupt ending of the setting precluded the continuing of the work this season. Table I Time of Exposure Spat per 500 sqe cm. Remarks in Patuxent River ; ub . 57 days 140 Heavily fouled with Barnacles, Bryozoa 9 days 110 Lightly fouled with Barnacles, Bryozoa Clean shells 165 Clean shells The data show no significant differences between the heavily fouled shells and the clean shells and so suggest that more work should be done along this line. Insufficient as the data are, they throw some doubt on the value of clean cultch in obtaining a good set if the cost of getting the shells down just before the set is much greater than planting the shells at a more 58 ehtsonod eortehtve to soe edd Bex asnatonte inseaeenuan: peed? «hteqne elgirte edt of bel mieietec lt 42 20 tolvartod Lovent ead! |) 08 gay aoltventteovel tently of -badIaoaed wor ete motow tetew ase ol henosasa ovew dolaw eflede Yo yoreto tite od? # Go enedmud of begoqxe goled etoted omee ie ah pearsall ph tr art's odd at hbeevonmt eno ellede waeld. . v4 ee To thotaeg Tol euwon tee fartosan on SOM wr) Jos ORaA Tavs ont Pr} . r ald mo egeteva add base mo et edt dqeoxs soelell didlw ees efferds ecodt ban eyed odd wi yfivierre booelq baa beddan gid? .saed etd al mobiet ta beoalq baa hoeddercoe ton et tebny bas seqga ditod nedw ¢galvicosor effete Bedduroe edd 008 seq teqe nam en edlwt Joomla to Jou @ ,beneteve ont ehovisoor elfede beddwiosns ertd BA 4 et 31 Das ybude ytantinifem sa ss bebroint caw phat abi “noo etom Dns tsey tedvons bemmtinoo ed you Nrow silt $2 ehotedday: Sonn aay BIBLIOGRAPHY Setting Behavior of Larvae of the European Flat Oyster 0. edulis and its Influence on Methods of Cultivation and Spat Collection. H. Ae Cole and hnight Jones 1949, Ministry of Agriculture and Fisheries-Fishery Investigation Series 11 Vol. XVII No. 3 Fishery Experiment Station, Conway, England. Setting and Survival of Spat of the Oyster 0. lurida and Upper and Lower Horizontal Surfaces. Paul Bonnot California Fish and Game Department 1937, Sessile Marine Invertabrates at Beaufort, N. C. Kenneth licDougal Duke U. Rate of Attachment of the Larvae of the Japanese Oyster 0. gigas as Related to Tidal Periodicity Milner Schaffer Ecology. The Development of Marine Fowling Communities B. T. Scheer 1945 Biol. Bull, 89-103. Growth of Sedentary Marine Organisma. Coe and Allen 1937 Bull Seripps isst. Oceanography 4,101. Significance of harine Bacteria in the Fouling’ of Submerged Sur- faces, Zobell and Allen 1935 Journal Bact. 29,239. Sequence of Events in the Fouling Submerged Surfaces Zobell 1938 Cont. Scripps Inst. Oceanography No. 35. The Attachment of Oyster Larvae T. C. Nelson Biol. Bull. 46,143. The Attachment of Larvae of the Olympic Oyster OQ. lurida to Plane Surfaces A. E. Hopkins Ecology 16,82. Experiments and Observations on Swarming Pelagic Life and Set- ting in the European Flat Oyster (0. edulis) P. Korr inga 1940 Arch. Neerl. SCI. 5,1. Investigations of the Physical Conditions Controlling Spawning of Oysters and the Occurence, Distribution and Setting of Oyster Larvae in Milford Harbor, Conn. H. Prytherch 1928 U. S. Fish. Bull. Vol 44,429. 61 aera us | | ante? wodeyO deft neeqomm ad? to eavial %o covaeen eMOLeoOl lod sia His nottavidtwo Yo abodtell ao vonenfial rere | eChOL Bono Idgtnd base ofod « Nolin eau Etateli-seliodell Sas enit fuoltna by vse gqawnod ,noltiat2 gnomiteqzd yrerdelt © som ITVK Lov ae “wroqda Dre B ae bo) ‘todey0 od? to sage to favtvane, Hae. at Bre Aats piante [20 “tonnes tuoi .soostave Intnortiaol sep avoel rte q Ad othe sou ,ito%Ivees Ja setendadzevat ontted | eV ofeG thai Beata oO tosveyo ecenaqat od? to eavied oid to tromiond3A aia . eYnefook tetterio® tenihi yitolieltel fabiT od beiaie Bel roonee .T .& ‘BelilnummcS gatlwol enttat Io tnomyolevedy EO L860 live okt FECL meLflA bas cod .anetnegt? ontrsil ytataebed, to die efOL.5 ydqatnoneso” .teel ee re begrondad to- “pee ot mt elvesoad ential to sonsolt VES,C8 .toati feonwol 8o@L amells bas Lledot ‘evowtan? bontomd ue srifwot eit al sineved Io oo 19 638 gO Yoqatgon20s) .ten! sqqtroe .tnod Bee £ oe wObL y ob olin «fOlG moaiell .o .T savaad toteyo To dnemioed Aue ensfi o2 alah “oD tot ay0 oleae £0 edt to eavand to tnomiostaa 4 088,0f yaofosh enfiiqot «a oA eoonag ~ton ‘see ent digatet yatwtaw? mo enotdaviend® bie none hae OPO rant mtON «7 (aifube .Q) teteyO daft anoqers’ odd ae ol, 8 ,10e free “a sient aniffortiod anol? fhaod Iaoteyl: edi to snoltegiver sedeyO to QOLsde® Onn solimélagelG yoonerveo” edd bas oxod ego elelt 4c .U BSeL Rae oH .foy ,vodysl hrot it af saveaiam 608d, 52 Sov shee re The Selection of Food by the Common Oyster Drill, Urosalpinx Cinerea, Say Harold H, Haskin This paper is a report on experiments performed in the summers of 1935 and 1936. It is presented at this late date because the results have not yet been published, and it is be- lieved that they are of some value in providing leads to fur- ther work to be done on oyster drill control. It is common knowledge among oyster growers that the smal- ler oysters are preferentially attacked by Urosalpinx cinerea, Say, the common oyster drill in New Jersey, In 1910, Dr. Pope, working for the U. S. Burean of Fisheries, investigated this sit- uation. His results, contained in an unpublished manuscript, were summarized by Professor Moore, also of the Bureau, a year or so later in the statement, "Thin-shelled forms of shellfish were invariably preferred to the thicker-shelled forms." This implies that the drill has an infallible mechanism for finding the easiest way to its shellfish prey. This idea persisted though Federighi, in a general study of the habits of Urosalpinx in 1931, noted that it would pass by the meats of opened oysters to drill intact oysters in the Same dish. Also Professor T. C. Nelson observed in the early 1920's that when drills were allowed to select food from a pop- ulation of various sizes, there were always smaller oysters among the survivors than some of those that had been drilled. This observation was repeated in more extensive destruction studies made during the summer of 1935. In these studies, oys- ters of various sizes, though of the same age, were placed in cages with oyster drills. The drilling in the experimental cages was at random with no apparent size preference shown, The fact remained that in commercial beds the smaller oysters suffered the heavier mortalities. If shell thickness were ruled out as the selective factor, how did the drills choose their victims? In the destruction studies all the oysters in a single cage with drills had been of the same age, i. e. spawned in the same season, although of greatly varying sizes. In contrast, on the oyster beds, the smaller oysters were, in general, the younger ones. This suggested that age rather than size or Shell thickness might be the important thing in food selection by the drills. This possibility was studied by experiments of three types. In the first of these, individual Urosalpinx were placed with a choice of foods in compartments of a wire cage suspended just off the bottom of a tidal creek close to its outlet into Barnegat Bay. The cage was examined daily and attacks on the 62 - omme) eetd. yd boot qae .sonentd xntgte On y ehame edt teat siewots Tedayo aos opbolwon common #f hs, otents xutalaroct ed beolgedin Yllelinoretor: w1n evade i, eqed «a .OLef al eCeetoL well al Litth *etayo AONMOS ede i) Ueels atnd bodastzeovat setredal to mend «2 .U alt 40% 4 vtaltonvnom bedelidugays as of bealednoo ,adfuses efi oe ss Rey 2 ,veoiwd edt to onle .etool tonestors Yt hoxzisnmames <) defi fede to emyot HelloedeentdT" Jnemedete ond ml ntedat i ein? “,amtot hollodeeretolds odd os Doxre'terg vieblyveval gathnl't tot melnanoom ef{dl [lata -aa cad L245 odd Jett eb “omy delifleia edt of yar teaka iy Youds Leteusey 2 at yidgitebet dyyodd betelersc sebt eidt oe! eesq Ditow It teds Hetou .LeGl a! xalelacox to édidad > ead al evedeyo toetal If£tab o3 tevexo Seneqo Io evmen it Wa Gltae edi at bevieado nouflet .9 .7 t0aeelotl oafA .«5,etee “Od 4 tort boot toelen ot Lewolle atow afiith aekw tony eteseyo isiiame eyawla erew. erect ,20sls euctisvy to ti sHelf{tah anced bet gars -aeoid Lo aoa nsis; eiovlvipa edd, Hobjourjesh evienetxe erom at botseqet .vaw noltevtaedo alt ) meyo ,A@elbude eeeds nt +GECLI to tommue ed galayb obam’s ot CO Aa «3 beoals Stew ,608 em8s oid To dnwodd eeste avoltay Yo: aii Latneminegqxe edd al pati lied of? .effind soteyo diiw 8® stwode sonetslesq ests iaotsqqa on Atiw mohoet #2 eat Oe e@tatnyo taifeme ond ehod' feloveimioo al gartd benlaumet ¢ ont | Relea evew seeniotds ffeie If .etdifadron yzelveed ei begs . tiedt oeoods effiah odd BLb wod «703987 evitosles edd ta? ) TYoniy by) 3 | efgnie a nt eredayo add Ife eetbude noliourdnsb add nt elt mt bonwage .e .f .eme onae edd To weed had eifinb dtlw . gteetines nl .sexte salve YLtesty lo Aawordd fe e1O OBR 1 Bde ,fatonog.at ,crow agetevo aeffame of? ,ebed sodage, of to esta nedd tatde+ ean garlt Dedsexnun eld? |. seno te |) Meltootes boot mt ontud Jaadtoqms ed ed idalm aeondoing £ ou 2O Btreomiasqxs vc Betbude sow yiifidiesoy elit sbeebs i Bhi. has >, Beoatq eter xntagtorct! Laublvibat e8edt To textd arid at.) _ bebaeqanve eyse ottw 2 to ednendingqaos af eboot Lo eslodo a, O8al goltno atk of esols weers [ebti @ to motiod odd ) Nt mo BHoadda bra vileb beatmixe saw ogao oct / shellfish were tabulated. Six Urosalpinx, each in a separate compartment, were observed with the same food choice over per- iods of time from 6 to 28 days. These experiments were done in the summer of 1936 so "1936 set" indicates oysters spawned and set in the current season, "1935 set" are one-year old oysters, etc. Results of the wire cage experiments are given in Table I: TABLE I WIRE CAGE EXPERILENTS - CEDAR CREEK, 1936 Single Urosalpinx in Individual Compartments. # of # of Drills Determi- Attacks Ratio of Food Choice Used nations Made Attacks 1936 set vs 1935 set 6 6 oe to 2 16 toa 1935 set vs 1933 set 6 28 42°40) (20 9 Sal tom 1936 set vs Mytilus 6 8 zo to 7 dao tO FT These wire cage experiments indicate that the drills do prefer the younger oysters but give no clue to the factors governing the choice. The second tvpe of exveriment was designed to see whether the drills actually explored both possibilities when provided with a choice of foods. Ten Urosalpinx were placed in the center of a flat Pyrex dish and oysters of different ages were grouped in opposite corners. The drills were watched and movements re- corded until they remained stationary for at least an hour, For one series, the final locations of drills that had moved to oys- ters are shown in Table II: 63 eoeiages: @ ak dome atnmeciienl sDeonsodea idan tet tevo ootodo boot omen eft H¢lw bovasedo sven ma a (> grob:etew ednonitvecxe sell wab 8S of 0 mov suid 't6: benwaye axvedeyo aetnolpal "gee O60f" 98 86L Yo ctonmue ont | blo tsey-eno ets "dee SSCL" ynoesen tnomwo oft at ae ftevts ois cinemitogxe egao ertw. end to etiueot it « | a maga | | aees pers ANGHD + OTUMITANIKE NOAD BATK i sednomsanqnod Laubtvibal a! xatgfasos efgate | to 4 40% %o oljsH e#osdsA «intreted efLind wales, 2h. peepee. eo onis aa ee a a eg den ner wl | fod £68 Of of Sd a8 9 foe to0t av 30 a £02 8,8 ¥ oF &s. 2 a euitdeh av —<_ oo ie aster ob efLinh eit Jatid etrotont einomtreqxe en#0 ontele Ralatevos etotont eff of eulo on evin tnd stotaye Tere 60 ‘torvedw o@e O23 pte pa paw teemiteorxs To eg d Sapoes eau hebivotq nedw setsifidtuseq dsod betelqxe . = ‘to -teceeat y : oe gotisainzesed - . g a ee "a i ie * a Pye & : g » z : s v } -, 0 ra] é : 6 9 0 v be ' . . 7 A. a 8 If es {atoT “fea ® eet otdes roel eid bre yaw eldd at, bersomoo eter aboot Litsh 10 rdelasy Pp mevin coldemrotal aif .VI eldest ct. bostanneue ete bentetdo ;III eelto® ee eted bes trannutre at Tit, oie TABLE IV OVERFLOW TANK BirvERIMENTS - 1936 Summary of Data Number of Deter- Dridis: tol Driiis. to. “voune™ Series Food Choice minations "Young"-01d" Drills to "Old £ 1936 set vs 1935 set 14 68 -—= 29 2.5 ag 1935 set vs 1933 set nye EXO Meret an ie Zee in £956 set vs 1955 set 8 alls) Vey Lal 4o1 nV 1933 set vs 1930 set 5 14 -- 18 0.8 V 1936 set vs hytilus 4 ior exeied 5 3.0 (Oyster) (Mytilus) The first three series of experiments listed in Table IV agree in showing that water from young oysters is more attrac- tive to the drills than water from the older oysters. Twice as many drills are attracted to effluents from the 1956 oysters as to effluents from the 1935 oysters, which are in turn, twice as attractive as effluents from the 1933 oysters. We might expect therefore that water from the 1936 oysters would attract about 4 times as many drills as the 1955 effluents. This expectation is realized in series III. Little preference is shown between the effluents from the 3 year old and the 6 year old oysters (series IV). This series indicates that the differences in ef- fluents which enabled the drills to distinguish between young and old oysters disappeared after these oysters reached an age of about three years. These laboratory experiments point conclusively to a domi- nant role of chemical attraction in food selection by Urosalpinx. In 1937 field studies on the migration rates of the drills pro- vided additional evidence. In these field studies various groups of oysters were placed in opposite corners of a 10-foot square laid out on the sandy-mud of a Delaware Bay tide flat. Marked drills were planted in the center of the square and then were collected on the following low tide. Results of a series of these experiments are given in Table V. 66 —RBdsd 0 cohen a tod faa ge" 64 efiiad od eLftad Pet p i to a , E8 es = 68. Ar gen abef ev gon a B.S | @& = 882. -: Sf tee Sc@l-ev toe 82, Let ff = ob 8 Jee Ser sv. toa a€ 8.0 . SL w- Af 3 tes OS@L ev sec Ait S (sotev9)-0.€ » @ © Bf b eulliyil ev doe BE teuifixi) = ~ Be a VI ofdel at Satell sdnowlteqxe Yo soitee ent? geantt, 17 “ostddn oom al stedeyo yao, mort tetaw tert gatwote ab. ag eolwr ,etatayo toblo ait monk qojaw asdd efliab aid oF Be atetayo doel end mort etneu[tie of betoerttia ors el lbad sa colwd .mws at ese doldw ,exednyo a8CL odt mort etnonkt doogxe dogin oW .eaedeyo SSCL od mott sineultte an ovitdl tyodn Jon1tde bivow ateseyo OSCL ont mov? tetaw dad? e6 moltatoecxe elit .atmonLite SSCL aris so efLixb Yiten 88 Bet meewied mode zl sousteleg efistd »I Il sqitse at fosilag Srssevo Dlo weaey 3 erii ban blo amey € add mort sdrronltde “te nl esoneretiib elt tecdd eetesibal aeolaee sidt oC VI a BAanoY asewitod detignti eth of effianh edt befdaene dotdw 8g ene Ae berorer sisteyo esodd 16ovts borseqanelh ereieyo Bike e8tacye contd ods _s 7. LL ae | “hmob 8 of yLeviesfortoo datogq aidaeniteqxe trotetodal. esedT emnlgiagoil yc noltvon{eoe boot ai aottonttia Esotneds Ia efe i -0%" effith ait to ssteq 10! Jarnin edd me selsuie- bfott ve eqvory evolasy tolbute blott ovadd nl. .eonebive fancltiobal eteupe tocl-Of a 30 erenios etleogge ai beorle exow saad 10. beltad ,teft obit yal exiled a to bimeyonee odd po Fa04 etey riedd brn etetps ni id ic seddaho ad? nt betanslic etew ode Zo eeites 2 to edivec!) .ebtt wel natwoliot edd mo betes | oldat nt nev ts ers as 08 — se a9 nies w — — —- = TABLE V FOOD CIICICE EXPERIMENTS ~ CAPE SHORE TIDE FLAT - 1937 10-foot Square on Bottom: Number of Drills on Drills on Young Series Food Choice Drills Used Young Old Drills on Old ay 1936 set vs 1935 set 154 42 10 4.2 EL 1936 set vs 1934 set 290 86 9 9.5 IIIT 19356 set vs l..R.C.* 150 78 353 Let IV 19354 set vs li.R.C.%* 1100 ep ioaS 0.235 *h.R.C. designates a group of older oysters of indefinite age tonged from the lWaurice River Cove. These studies were done in early summer so no current sea- son set were available. The preference ratio for l-year-old oysters compared with 2-year-olds {series I) was 4.2. As ex- pected from the laboratory studies, this ratio rose sharply when 1 year-olds were compared with 3 year-old oysters (series II). The decline in ratio of preference between 1 year-old oys- ters and the older layrice River Cove oysters was unexpected (series III). From the results of series II and series III it was galculated that the preference ratio between 1934 set and Maurice River Cove oysters should be approximately 0.25. The check value of 0.23 obtained experimentally in series IV indi- cates the value of this method in measuring quantitatively the relative attraction of various shellfish for the drills. It is of interest to speculate why the older oysters from Laurice River Cove were more attractive to the drills than the younger oysters. The three groups of younger oysters all came from an artificial oyster reef on the Cape May tide flats where these experiments were performed. This is an area where rapid growth and metabolism occur. In the Maurice River Cove areas, from which the older oysters had been tonged, growth is notori- ously slow, but these oysters, when transplanted to more favor- able growing grounds, frequently grow very rapidly. It is rea- sonable to suppose that these Maurice River oysters after trans- plantation to the Cane Shore, were stimulated by favorable conditions to rapid growth and high metabolism, a state charac- teristic of young oysters. The Urosalpinx reacted to them as though they were very young oysters. Such studies as these described in this paper may provide valuable clues in finding more effective baits for traps used in control of the oyster drill. For example, Dr. L. A. Stauber 67 V ISAT oh | veer = TAT: SCIP WRClS A400 = erigitagsxs cOnO | aad mt snotsol to svaune toot-OL 1 do eff{l eno Ovod tevlil eotral adv of m9900 melfodriom Daa te? . im 7 unusually uniform for the entire southern two-thirds so far in- vestigated, this summer varying during the phases of the tide cycle only about one part per thousand, away from the negli- gible influence of a few small creeks along the western shore. Temperatures have also been relatively uniform. Maximum cur- rent velocities vary from about 1350 em./sec. in the inlet to about 12 in the middle of the Harbor where most of the larval Sampling was done. Larval studies are most productive when sempling is done at close spatial and time intervals at, at least, one central carefully selected station. lLarge concen- trations of adult quahogs occur in the southeastern portion of the Harbor. Observed spawning of the quahogs in Little Egg Harbor over a three year period extended at least from June 10 to September 4. Depending on water temperatures, additional observations in the spring and fall might disclose a longer spawning season, As ascertained by following quahog larval swarms from the first ap- pearance of the straight hinge stages (when they are approxi- mately one day old) to disappearance of the oldest stages from the plankton, and checking the size of the larval shell in re- cently set quahogs, the larvae grow in size from about 98, to 200 x» in approximately 7 days. There seems to-be considerable variation in the duration of the pelagic stage, however, fast- est growing larvae setting in probably as short a time as 5 days and slower growing larvae in more than 10 days. Growth of large larval swarms is fairly uniform up to 140, and takes about 4 days: after that the size range of the individuals within a single swarm continues to expand with age. In the three years of study the greatest concentration of quahog lar- vae encountered has been about 2,500 early stage larvae per 100 liters of bay water for each year, occurring in July. The old- est stages of larvae, however, become so scarce that it has been necessary to pump 500 to 1,000 liter samples to find them. Rarely are more than 5 ready-to-set larvae pumped per 100 liters of water. Mortality thus, as with all free-swimming bivalve larvae, is exceedingly high. So it would seem that normally in Little Egg Harbor quahog setting occurs over much of the summer and in relatively small concentrations--the phenomenal quahog sets of local folk lore have not yet been encountered. Insufficient serial vertical and horizontal sampling dur- ing tidal cycles has been performed to indicate whether quahog larvae exhibit detectable migratory movements in the Harbor. Horizontally the larvae of extensive spawnings are found through- out the Harbor and at all phases of the tide cycle. Smaller Spawnings may remain quite localized in a smaller mass of water and be traceable each day only by means of the phase of the tide and the depth of the water at a standard sampling station. By means of a series of periodic vertical serial samplings through the cycle of the tide it was observed that the maximum larval concentrations during daylight hours ordinarily remain about one meter depth from the surface, and that these concentrations move to a slightly higher position during maximum current 75 ea iris of ebitdi-ows atedduoe ovbksne. edt at’ . “@hIs: ed to: xesede aid SS ee ywev we (GLnd _Dod. _seiigon odd mott yowa:, baeevotd teq dtaq eno Juoda xi ge%00e stoteow..orft nools ateox Ifame wet a to eoreul? efvs mimixs .oolLing ylovidaler. need oefa ovat se bse" OF tefnt et? al sooe\ eto. OSL Juoda mort yiav gelitoolev ™ faveni ait to toom onsedw todas+ aid to elbbia end Fe nodw -evfsoubo1q Jom ete nelbete fevisi snob eaw gag . o@",ta- elovastel emit bas. Ieiteqes esolo ta onob el nak etesnoo syisl ,.nolista Sesoelos yfivietso Isiiaes eno to solénog ntedasentues eft al tuo00 apodaup diubs To Sao ; : 7 « TOC "SE i, w : + Bm tevo todisk net eftvid ni anodayp odd to antowaqe bevtesd®) “ediaiqedc o2 UL enul riost gesel ta’ bebnetxe bolteq teey eee a al anoliavivedo Lanotiliia ,cetuéateqmed tetew- wo antinegea , SA rettonecé gntowaqn tegael o eseloelb sigim {let base gala * “qa vexltt mi? mot? amsewa Laviel goraup aittwolfot Yd hemiag a ~Ixorqqs 82 told madw) seyade oeariid tdoleste ond To eons , howl eeseda Jcoebio ody Yo onstateseqaelS of (Sfo yah sno ue ak “wet al Ifee favrel odt to este add natiooto bas ,nodingg | ' “OF «6% Juoda mort oste al wor, eavist odd ,cnodeayp de8 ¥ efveteblensco od-o2 emeen stediT .snayeb V ylotamtxorqca 22 “$0a2 ,tevowol ,enais olgelon ei? to nolisivS aid al Aone 7 G ua enmtt a store ta yidedorw mt palitoe eavaiel nalwere | Hdwoud seynh Of aedd orom al savitsl galwonta aovole Drew © sedeay Daa , OBL oF ay mroitaw yininl of emravs Loevesal one 6favbivibat edi to epnet esis oft dott sotdta sere & ia ed3 ai .one ditiw baeqne of eouuttnoo matwe ofgnite A ae ne, weal aodem ‘to aoldatinconco doetcety ald Ybuis To ecaegt a8 OOL "cq oaviel enete yites 003.8 duods toed sad boredawod i. “bio eiT .yfit al antitvo00 .imey dops tol a93awv yad to Be oe | Bad 22 Jaid eous0s of enodsed! ,revewol ,eaving To 2sygeae | eiied2 Balt oF solqurs tottl OOO, £ of 002 amy of yumesesene erTesit COOL taq Beamiq eavial icon-oteyboot @ asd? otom ete WN evisyld gninnivea-eett ifs diivy ea , cod ydhLetcol 6 al =) t i ay Mf Yilenton tait mees bfuow 42 of sduld yfaatbeeoxe ef qf q Tamme os To town evo ciuooco galddeu godsup todtek a8 of gedaup Lenewonoiq: oid--snoliesteoongo ILame ylevitalet Bee . sHeretmvogna aood Joy ton eved otol s2fot Isoof Tey etub palfqhes Iatnosttor baa feolisev Isiaen taeletiigant @ Borlayp torivecdw ciaolbhnt of Bemtotueq need and sefoyo Lebiae etodsal ed at sinerevon yrodstain efdatosteb dlaldze eam o)\ siptonitd fatfol eta. caninwage evieastéxe to eavial eld yiletaoss es . ..Solfem® seforo ebti' oft %6 sesady Ifa to ban todaall om ge 7 Today to gaam tolfome » nl bostiaool sil vp nlamet yam enniowag "> ,@b23 843 Yo oearia et To. onpon.¢d yino yab done eldmonatd ed B ‘Gh snoliase gaifques husboste 2 te satew edt to Adem eds . agrordy egnifamas Lelros. {aotiqov stbolseq to seltes 8 to annem .. favtat murmtxem orld dent bevieads caw tf obid oft to efoyo ene i Jvods miamet yilaenifao.etuol Idatlyad gated snotiendagor . @ntoltatinesnos oeedt tedt Soa .eon' lave ed? mort ddqeb wedem ef an tneitn muninan yatwh coltteeq tedaid ylindgifie @ of Oh x i ; 0 A ; ‘< ‘ ae ee) ay velocities. During the day the larvae seldom occur directly over the bottom. During the hours of darkness, however, pre- liminary sampling shows the larvae more widely distributed throughout the vertical column of water, extending to the bot- tom. The stratum of maximum concentration also descends. Here then is a possible response of the larvae to light, which bears further investigation, LITERATURE CITED Carrier, M. Re 1950. Killing and preservation of bivalve larvae in fluids. Nautilus 64: 14-17. 1951. Ecological observations on the distribution of oys- ter larvae in New Jersey estuaries. Ecol. Monogr. (in press), Lebour, M. V. 1938. Notes on the breeding of some lamellibranchs from Plymouth and their larvae. Jr. Mar. Biol. Assoc. 20: 119-145. Loosanoff, V. L., H. GC. Davis 1950, Conditioning V. mercenaria for spawning in winter and breeding its larvae in the laboratory. Biole Bull. 98: 60-65, Smith, Maxwell. 1945. East coast marine shells, Edwards Bros., Inc. Stafford, J. 1912. On the recognition of bivalve larvae in plankton collections. Contributions Canadian Biol. 1906-10: e2e2l- 242 ° Sullivan, C. Me 1948, Bivalve lervae of Malpeque Bay, P.u.I. Fish. Res. Bd. Canada Bull. 78: 1-36, Thorson, Ge. 1945. Reproduction and larval development of Danish marine bottom invertebrates, with special reference to the planktonic larvae in the sound (Oresund). (With a special section on lamellibranch larvae by C. B. Jorgensen). l.edd. Komm. Danm, Fishkeri-og Havunders., Serie: Plankton 4: 1-523. Wells, Ns Te 1927. Rept. Exp. Shellfisheries, Sta. N. Y. Cons. Dept. 16th. Ann. Rept. 1926: 4-22, 74 ebiesetd "ti/3 G0 nnditen: nie on hay tevowod. ,seemiteb | to etwon a . \(betudiitelb plebiw etom eaveal ed? -ewod qm “eted oft oj volbauoixe -,adtaw to mmefoo: Taottaey ; ete ‘.ebusoneh cela noldgidnsonoy ‘Muriheen to putette oe doldw ,tdnti of eawarl edt ‘to: wenOge St oldiesoq a ek. esos tants acres m : “GEtip- Sanaa it ia “ah sh © {eblult «l-saviel evinyid io noltstreesiq: “ban gakl inn ey | | aViwbl rho aullosal i -e70 to say toed rs ond ‘no: ‘sroltevieedo- fsolnoloog ‘gLiChe ies ertgortors L094 ~solsautee you ts) well ay savestl 193 | : sletenq at) V¥ mort edoneadtirenal: erios ‘to. aalbeewd od? ‘mo Revol sposedA ,foll ii .ab en rrih-e a sions bas ddpomyg li “~CSL6OLL- 36S ; _ Blwed:.d sl pel Ve “gotatw ont gritawags ‘0: edaan secon +V. jartno ttt bao? “efoltsé “sttovarodal oid af esvial edT. antboerd: Bas x *4o0- =O3- 780- ei fe j (e0Al , nord shtewbd - .eLlete etteam danog $00 waned ” ronan ok mi eavtel. evfavid-*%o nottlasesst endy a0 tila olG nabbeazd's aol dint rinod - ,eaotigelfon H} aXe, -4 889-099 ol ed vinyl "Bef AOlT 6 T.i7 est expecial to eaves t ev lavids - 9&. if ,08 eae? *iloegso ery ert LO 84009 .onawnoniaag ods ediisxo of cantly bojateg Aoatd Atlw bexevoo ome 79 Sedaw doldw Anson + - sexod nebaow eq7zal al Beoalq ete ynateice s palainialen endy ,ootanes caw etrtateqned If qetay seo di iw Selllt erew doldw yedooro and abad tw ent otow Bi ors osaoliqwl setes EPL nosdos dold3 dnsonmd: owmieteqnes A989 gnimb bejoswbnoo eaw tnemiteqxzo oft to Itaq tagatat,) e800 Jo0m Anvolt ow Ab ont? oie .yalaqe zvitoe ban sede Romesool) Sete astew ed? to enutatecnad oad “Tots 160, OF eam Of Deaeiiibave o1ew dolce exalo mort nedlst. cx meade a Moorea Blava of .( Oat ceived bas TYioacsool) Tosh Gi ©? Bestewol 10 gi ‘tayo 1 ¢ifavbars etoev ea0 boxl {ia tifawed .heiifws ed oF ‘anew vec? doldnw af oonuso-ragen Eatvests aud) ioe tiene al Seonmhestal onew onas GOheas _todAw 25 YeIll veg agge OOO,Ue to noliaidaeonon Lata Hodiien edd yolew iy ered owt yteve bennedo sioy setud ine Sam Yeah te ety Sesin «(OCG .cival baa Toaasacod) had litaes® BS: fexoi dd to orodx in ® Dol etonw candivew ad’: bagnado: ond anne4 of? to aliedoad auifve offcmy A me Taedont ron oa sets S einer eemalue odd a2 mies Bkaet pad tiHitns Go afleo 000,008 baa elisaoldy to eLfeovgig “oad Titi eis tacld vied benol thom, od. yar ot tsiav Ia ee WeoMmew coal) ets} “yo ete ye boot sa hatoo ot orem dotelw, paves O89 VI hoteliniaue chtneta , qd@ bia of, ceded. ate ae ‘ ONS CL .PetavGnoo atex atnentadane tof .am tue ee OFF OD syer oea00) eit Lttiqw beawweaen ervey envi en ris - Serwel or ai? tie most envied qtevowod . cinorninegxe Paewee y ehotibaliiin) tedte yah buoses ond Yo bie eft do Dowager 0 Mit £B ApHt eh ebay ovo Binoretunsay demi ies iy reek of beinpteo toliv erste enald ddafeadia add er RO ProeUsiewor ro" soled azaw envi Of Noor, i, Um al 3 etow souud lin ot eousood Yay eo: Vik cal bd rose 401 alguee a wa ‘nored savant 9 noone eng ay group was actually 100. As a rule, in all the experiments the duplicate samples showed extremely close agreement. Measurements of the larvae were made in the usual manner, using a Sedgwick-Rafter call to hold the larvae. Since each of the small divisions of our ocular micrometer was equal to seven microns, most of our figures were based on these intervals. In some cases, however, when the necessity arose to determine the measurements more precisely, the larvae were measured under high- dry power where each division of the ocular micrometer was only 1.7 microns. In general, however, it was found impractical to be confined to such accurate measurements because the variations in the measurements of the larvae depended to some extent upon the position in which the larva was lying on the slide. This was especially true of the older larvae the shapes of which were es rounded than those of the young ones, which were relatively lat. RESULTS Our discussion will, at first, be confined to the tempera- tures within the range of 18.0 to 30.0°C, The results observed at 15.0 and 33,0°C, will be discussed later because at these temperatures the development of the eggs and larvae was usually abnormal. Within the range from 18.0 to 30.0°C, the mortality of the eggs and then the larvae was comparatively low. it is estimated that often not less than 85 per cent of these were carried to the stage of metamorphosis. The only exceptions were several cultures grown at 18.0°C. where somewhat fewer eggs developed into larvae of straight hinge stage. However, those that reached that stage usually lived through metamorphosis. The larvae in all cultures appeared and behaved normally. They were usually vigorous swimmers rapidly moving through the water, this condition necessitating killing them with formalin before taking their measurements. Their color was usually pinkish-yellow-green characteristic of the type of food they were fed. Incidentally, our experience has shown conclusively that the color of the larvae of V. mercenaria, as well as that of the larvae of some other lamellibranchs, such as M. arenaria and M. solidissima, with which we worked at different times, should not be considered as a reliable specific characteristic that may be helpful in identifying larvae. We formed this con- clusion because we found that the color of the larvae may be changed at will, within an hour or so, by feeding them micro- organisms of different colors. The data on the growth of the larvae at different tempera- tures in Experiments 1 through 4 are given in Tables l, 2, 3, and 4. 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Fy aaah y palerhanst Pd den ne An tee ame mS + eet tthe aneth sr omnneeshaettal lang wey ie ee ¥ . 1 : yee at yas - . Athy 1 arm ise erp nse ns gare vei datip » 2 BS B'S ri | I ‘ i * ° : ‘ . tor eretiobe etme rere “Sipsewrecnssy: niece Aeterna anitn Faia ed el eh ing OARS EN SOTERA SN ~— ‘ a fo 0 pemepeetpg en wn hota “5 Ng bit ai of the larvae as determined by the measurements of representa- tive samples at two-day intervals. The exception was, as al- ready mentioned, Experiment 1 where the larvae were not measured until the end of four days, and where no measurements were made of the larvae grown at 18.0°C. on the eigth and 12th days (Table 1). In Experiment 4, which was conducted in the early summer when the water temperature was already higher than 18.0°00., no cultures were grown at that temperature. Before proceeding with the discussion of the results of our experiments it should be remembered that metamorphosis of a larva into a young clam is not as sharply defined as is metamor- phosis or, as it is commonly called, setting of an oyster where the larva ceases crawling entirely and cements itself to a shell or other clean object. In the case of V. mercenaria, as well as some other clams, metamorphosis is rather an extended process beginning with the gradual replacement of a ciliated velum with a large muscular foot and ending with the development in the foot of a functional byssal gland. This point is often diffi- cult to establish because many young clams, although possessing a byssus gland, do not always attach. Therefore, it may be dif- ficult at times to distinguish a recently metamorphosed clam from an old larva, especially if the animal does not move. The length at which metamorphosis took place in our cul- tures ranged from approximately 175 to 256 un, occurring most com- monly between 200 and 210 yn. The largest larvae did not always metamorphose first. In several cultures some comparatively small individuals measuring only approxivately 180 y did metamorphose, while larger larvae, measuring more than 200 p, still continued swimming, displaying a powerful velum and a comparatively small foot. In the course of these experiments we tried to determine~ whether the larvae grown at low temperatures, such as 18.0°C., would reach a larger size before setting than the larvae grown at higher temperatures. Some of the preliminary experiments did indicate a tendency of this type, but further and more ex- tensive experiments did not support this contention. So far no definite evidence is available that such a rule applies to the larvae of V. mercenaria. The results of the first experiment showed that, with ex- ception of the 30.0°C. group, the rates of growth of the other four temperature groups were closely resembling each other, in- dicating that within the temperature range of 18.0 to 27.0°C. the differences in the temperature do not always significantly affect the rate of growth (Table 1). If plotted, the data would not resemble the exponential growth curves offered by Medcof (1939, for the growth of larvae of O. virginica. Furthermore, contrary to the findings on some other lamellibranchs (Seno et al, 1926) the larvae kept at 30.0°C, did not die but showed healthy, rapid 82 me InesetdeT "lo 4 the, Se ae eR ad in aoKe an? | ROTAEA Ht POM Orch seaweed ocd eradis f POMONA i gua ath HsnPuonteeow orf sh why brie os Br WeROaT) erah ith! faa diate ond ae Pag 0 2 i mech opyte femun vites ali af Seo Mbaog: Bai doldy ob detemboooa Of ye SOO.8i mats noigin vime ile saw etadanegned sadey ar sab caw Snomiteque aniwolfol aft ‘Redan eve vintage i saoomeiettlh Move to svaadtoael etl baie mee efieoo Laoivnght to Seoddatie etew savinlt to gecud fig st eeee Ves : Hotetes stew moots emoG seooheret Ltd taagitinghs on Bevrods ,ovid wt arog mu Bay Nt ngitoetes to eorseh tt hay ne POTTED ott?) eon le em e¢ods Had welfeme Yidataytogat ‘prow I hp shied 26 ‘s ; ened Vant Sheen tan nw dearnitnad ke botgisen yiielo page BE . Boda? ais nl eeocute? kIb ottd at ote tun bOKt SK $0 ovo SOM i if hcl il 40 serortto Ii eet Rh orbdoml earn l ete hee ad iN -eted ett dad? yinrecey at Seow 2 baa & 8 evnombene 7. -SeQd woh de nord dotd te Btced ere nay maven ait ‘to die etter aeotd nt cove revewdl: .(> Sas © 8 seloet) ome Stoqst itt uot Mrs sol sed ae eter Gy I oaee enemas ntaftras eal 2827, 000) ors 32 fworte vide de etd “rd idiiel (ei ene io qivorn 40 OO.On eds To Mads herd tet eer Dadiwende. Came had tat edd Yourdtworg to otet aan ai} dromtadee Jatt caetd Sige ote yyab state acd Litto | ene | . ani" cea OPO LSS ocld. mewn “Oo conta) a(t eight " sOP0,0% dia several ond! ans * Lf Levees, reer! ire Barges At the temperature of 50.09C. setting of larvae in some experirents began as early as the seventh day after fertiliza- tion, but in others it was delayed until the ninth (Table 5). The entire population of the cultures kept at this temperature metamorphosed within five to seven days after the beginning of setting (Table 6). However, the total range in days between the beginning and the completion of setting at this temperature, as based on all four experiments, extended from the seventh to the 16th day after fertilization and covered a period of nine days (Table 5). At the temperature of 18.0°C, the earliest beginning of setting was recorded 16 days after fertilization, and the latest, 24 days after it (Table 5). The range in days between the be- ginning and the completion of setting at this temperature extended from the 16th to the 30th day after fertilization, thus covering a period of 14 days. It is important that while in Experiments 1 and 3 setting at 18.0°9C, extended for 12 and 11 days respec-~ tively, in Experitent 2 it was completed in only six days thus indicating considerable variations in the behavior of the popu- lation of clam larvae kept presumably under identical conditions. The number of days needed after fertilization for the be- ginning and for the completion of setting of larvae at the three intermittent temperatures of 21.0, 24.0 and 28.0°C. are also given in Table 5. With exception of Experiment 1, where setting at three different temperatures began on the same, the 14th, day, the number of days, in general, increased with a decrease in temperature. Furthermore, even in Experiment 1, the range of setting in days increased with a decrease in the temperature. Thus, for example, while at 27.0°C. the setting was completed in 20 days after fertilization, at 21.0°C. it continued until the 24th day (Table 5). The number of days elapsing between the beginning and the end of setting in the cultures kept at different temperatures did not follow a definite pattern throughout all the experiments. Experirent 1 was the only one in which there was a definite trend showing that the number of days needed for the completion of set- ting of the entire larval population decreased with an increase in temperature (Table 6). In that experiment 12 days were needed to complete the setting at 18.0°C,, while at 30.0°C. setting of the entire population was completed in five days. In Experiment 2, however, no such relation was found. In fact, setting was completed within a somewhat shorter period at 18.0°C. than at 30.0°C, Experiments 3 and 4 in this respect also present a some- what inconsistent picture, although Experiment 4, in general, resembles the trend found in Experiment 1 (Table 6). Our studies showed that the larvae, which came from the same parents and were kept under identical conditions in the same crocks, showed sreat variations in their size (Tablesl, 2, 3 and 4). Taking, as an example, the measurements made in 84 ae rn pee 36 3 and¢ten ‘abab ios: rene ebkilisret teite vad dimeven ont ea vitae cu | Pat ‘elda'v) Atata edt Lidew Beveled aaw 32 arette erintanogod elad ta tqed eevudion edd to matt, Vi. galantsed off settle eyab Aeres: of ev kt hidhle ‘De moowsed ay26 mt eanes fatod acid vtevewon 40 aldal), gag aeamieseowod efit dn antijen to solvetquas etd faa aatad of diceven eid tort Sebnetxe ,etnonftegxe shot {La Aa. ‘enta to hofieg # beaeveo Sra aoltesifideet wefla yeh, F 10 Bohnals ed duotiaoe ani pD90 68 33 enuigesoonedt std. qteoias add Dis oltastitdyet setta ey Sf Sebtodet ear) ma wed ait avowded sy2b af apres oat ee eldel) ¢t! tedte I) Bobneixe eivdaneumes ald? ta gniddoa to moljefqmqo ot7 Pas i (pettevoo amis .nottdagif{liael, teste gab goo at’ (od. Hoe ie «|= SEM teaKs at elisty, ool dead tor 7a ah 1) .oyab bt oo) _ “dar nett onee {f bare Si x04 hebnedxe .%6OL je noltdes in eertd gunk zie «foo a2 bejolqmoo eay of 8 Jaen Laeqee BP 3 mod ety LO nol 5 jed oft nf suHofieiasy efdnyvebienes astofiibaos feoltdeb) swebau vidauveetqg dqo! seviatl mals ar ; ad oft to noljasli linet wadts Bebeen prah to necpua eH _ eins odd. de eaviel to sntttes t6 noltelanco me Tol baa Bay. heres O6ls etn 090.28 hae OAS more ee fo esiiiane ed taedeae i. do untddod oxonw ,.f Jnentieqzs Io nalicnoxe Hit see a Yah .AdaC ait ,amas ont sto ray ed seapiaiensed tteteame ‘ nt penorosh b tlw bessorsnl ,Jeitea at ,arab te to opnet edt .f diieultaca wl nove Saipan seTuensqrist ond rt saapsiosis 2 digits Besadrs eysb bet eiqnoo asi dat ties edt .f°O.TS ta of tay «stqjaaee, ts) Iitay bomalinos gf .v 090,18 jo ,noidaxiiidgiet teste | (& aidat) edt ‘he nationty oct at? peawied sniscate t{ab “Lo sedis, | Borarsuied Icateltib te dyes somettiro of? mt gull dee sadheminedxe edd Life tuonuromty anetiey edtalisd g. #woLliok Snead aiinlteb « dow enedds doldw mt eo ylao ent aay fog “S08 du GoOlsetqnos odd tot bedoart evabh Lo tadnga edt Jada easenoal ae Adiw besseroeh mobtefaceq Lavial otitis oak, ~ \febeen erew ayab Si Snomsronxe dod at fd oftet)) etka aie | dito gOPDWDE: Sm elidw. 008 ta galdioa end) omme Fant sp 7 SKE Wh weyah eves: al bejeteaoo vm nolda tage: mm ar ony cea gost at bere? saw ol t¥eten oud oe ney i ae odd 4.20. OL gn bolted “odode Acdeonoa «, tbs ty bea | reno 2 tapagng ocala Joordon elitd nt} baa ¢ Rapier bo ef, gitKO Og! AL. git inoutneaxs Hywotdtas Bey sie gy ld efdat) f Bronte al Bruny) Pirek oid mon ona Ho tely Cosvent eds tartd homed’ th 26) ‘ee hay ni iio. tt 2bitn6 featdaebe cobit tqeu siew Dee od etary ste thee ot eroltainay dmenn (fanny Ad, aber ei nenomanen banal qe lanene hail hi) wh si TABLE 5. Number of days needed after fertilization for the beginning and for the completion of setting of larvae at different temperatures in each of four experiments; range in days between the beginning and completion of setting, and the maximum number of days during which setting may extend in cultures grown at the same tem- peratures. 85 | edd “ok notensrtiived softta boboan “a _") saute eavael to Lagu So to noltefqmes ens sot Dna gutanined”) Keitenineqxe avot Io doee ml: exctareonet tne lMlo ga” fo moltelanmbo Brie ‘ya Lanksed wis aoowled eyab | at enced”) dolce giilayb ayoh ‘to tec momtcan add bow. Bal dgae, ened emsa ody te cre nS genuttee at Bnedne gau anidtes: corsa Py aX fk ‘2 Tee 3 O 2; a Ae i J mee ) } Sse l l eaerd Rt | Biy | TABLE 6. Number of days elapsing between the beginning and the end of setting in the cultures kept at different temperatures. NUMBER OF DAYS Reo \ q expe NO. 4 Expte Nowe Bxp be NOe lon! Miers Noma | 18,0 | 12 | 6 11 | a8 | Reo: | 10 : 6 | 5 | re) leaco | 8 5 : 3 a Ve | 27.0 6 | 5 | 5 : 4 | 30,0 | 5 7 | 7 5 | : | ! | | 86 Bete | itd cc Led ent hoawded yivk agate thorettis da dqew avtailwo add al nate (RR Te Rte! ee aN dS ie SAE AUR Had vy ee i) Gre oe Oa aden eon - iGO. ST Se 9 ON (tap re vp \ ise erp 4 ype dla petra mAbs SR IMA ee te eds ; r i ' f ‘ ae to)! Aakteatel 446 bo Bete vate oath One atagieds Experiment 2, one will find that early in the experiment, on the second day after fertilization, the range in the length of the larvae was comparatively small (Table 2). At a temperature of 18,0°C. it ranged between 93 and 107 mw, while at 30,0°C, it extended from 93 to 121 m. However, as the experiment pro- gressed, the difference between the minimum and maximum sizes increased and towards the end of the experinent the length range of the larvae in the 18,0°C. culture extended from 150 to 221 yp and in the 50.0°C, culture, from 150 to 207 ym. At some inter- mediate temperatures, for example that of 21.0°C., the differ- ences in the length of the larvae, during the last days of the fey? were even greater extending from 156 to 228 yp (Ta ble 2). The data offered in Tables 1 to 4 inclusive gave only the extent of the larval sizes without showing how prevalent certain size-groups were in the larval populations. An example of such length-frequency distributions is given in Table 7, which is based upon the measurements of the larvae grown at 18.0, 24.0 and 30.0%, in Experiment 2. The temperatures selected represented the low- est, the highest and the average of the five temperature classes. Experiment 2 was chosen as the example because it appeared to be most closely approaching the mean of all four experinents. At the end of two days the length-frequency distribution of the larvae in all three cultures was relatively uniform occupying a comparatively narrow range and showing a modal class of approxi- mately 107 yw. Between the fourth and sixth days, however, the differences between the length-frequency distribution of the larval population of the three cultures had already become promi- nent. The differences were especially evident in the sizes of the modal classes. While for the 18,0°C, group this class at six days measured 114 yp, for the 24.0 and 30.0°C. groups these classes measured 129 and 143 mu respectively (Table Lin As the experiment progressed, the differences in the length- frequency distribution of the larvae of the three cultures re- mained significant. In all instances the modal classes of the cultures grown at higher temperatures were larger than those at lower ones (Table 7). Our data also showed that the length-frequency distribu- tions of the larvae grown at the same temperatures but in four different experiments were not always closely resembling each other. For example, examining the length measurements of the larvae grown at a temperature of 24.0°9C. in each of the four experiments, we found that the differences in the modal classes of the four cultures became apparent as early as the fourth day (Table 8). At eight days these differences became even more sharply defined. On the 12th day, while the cultures of Experi- ments 1 and 4 showed considerable agreement, and the culture of Experiment 2 was not creatly different from those two other cul- tures, the culture of Experiment 3 was definitely deviating from 87 eo Nasu ence ont mg etna “4 saad Hatt. | Me dinnel oft ot oxcat oft ,cotdastiiies? ted? etiiateguet a 1A .{S afdeT) “Efome vioviteragnos..: ety 0°08 ta oftdw yu TOL bas BO ceowied Benmed HE), sotq dnemiveqxe eld- se ,sevewoH im SSL od SC merry |, toate monixean Sas mimindm ett Heowted eonetet tio ed (spas a ae oft dnoulaecxe odd to Bre edd ebtawsd’ heen Sg M £89 of O2L wort hebaedxe axe tuo 09.8 edé al. ke etodat omod I/ at VOS od OGL most , ett ive .090.05 oF WUOTILO ot °},f8 to dad? ofqriaxe tok, ,eoudevatined Ne ed? To eysb Seat add: galdtun oewniet od? ‘to dS pret on Be, eaT) m 8S of OOL mott Ribbactxe wetaenm) asve eae) ond yino evan ovianiont Db of I eofasT al bevelto edad alestao tneleverq yor arttworte dutoci ie wsosta Lavasl ad? douse to efqmaxe nA .enolieluqee Lavaat odd al eto ‘ogy beead et doldw v. ofdat at nevis 6f Braltudiatetd yonepay 0°0.05 bas O.b8 ,0.8f ta nwory pnytel ‘edd to adiemetivece | “wol et? Sotuevarget besoolex ceiuipreqmad sat 4S bate sBesealo ortateqried evil eff io ex,ateva old Bas Jaodntd 1 i! ot berasaqs i?’ auaced efqaare © std a6 ‘neseds eaw'S fem ae = eattion Ineqxe yo. [fa to naaom ed? naldasoteee Ytoe solo oe yl ' ‘edd to moldudingels yononpert-dtnnel of eyud owl Yo Datgaa ee! sui¢quood mioiianw ylovideflot ead Sous lun seni: {ia gt. | slxotqqa to anals fabom e sniwote bra @vapx wouter tlovida® aid ,sevewot ered dante boa dituol ott neortek wth FOR 4 r ; edd to nolsigdittelb ysnegpett, Pony, pO 4 fe be V9 Crh Ey Or 7% Fl te as Rae | adh of <4 ~ Oe veo OF 9 OY ben dew ee BD Sts ian ae bea bs YO Fee bee Or pe © Ga rare tein ve o* On Re fe ty ee Rp RBaRe os at few “3 yeh Ao ie) vf" ae as a sie ey ~ ated BR ae BRRARB BERD brs, wy fine at tia bay) id Fd a) iI ‘ Mu i pena ie Mi snort i aca gh sete td yan NIVORTE SI A mi yal aensy 43) Dhak my ges gga fae Ee bSe imenr ion (expressed in per cent) of larvae of different ages grown at a temperature of 24.0°C. in the four exper Length-frequency distribut TABLE 8 No. 4 No. 3 Noe 2 16,18 20. 2. 6 & 10 12 1) 16 18 20. 2 No. 1 | EXPT. fA hed OE Otte Miniiiil tL. = wiih Mee a ee eval ee aes A oaia ces et 1 NAAM OOOOIN Te HANdd NHAM-ONNDA+tOOr ee ade = Si Ard 0 ANKROMNRA oS N ay Slat ec | TOON StADNHS = AANdH Nodanran NOVA NIngwo mre ANH NAN NO OSTTOOW N Saaa Se Gas ang ane ® oONDANONN NAN = CVO LO AO Odd SPR eas | nN Ar HMDOWOR> 4—-t wo aod Aa oO AIA noord bal ait ot NANA MAA Oo Ae aaaed womrwodon | ad re Toy | wmVO- TON Tene en = Aten Ke wa AaAnn ATtTAHADWANANN ANN AS OAR BERR gh . nee oe By pam dad os kEeorwn th ; eRnEER™ » | 1S YtV : SE RRB YS ‘ Ane ORS STUNT > te ei ste ee ee ee a —— sone Por Ok § 7 BkR * econ wan eert 70 fy > OO OF OD? ps . Naimeini dom eyawta siew eullateb fo nvo%Ks cortud Lie of ae BA. .WLtedosd ritw setuixty atl 26 ol Lenokdy, da ls fect erated noltevieds mosh both aedto seus ine Dol-outl eee eodeidlifenel in aslooge aoe) 3a. paviat o. brome eto dre tireqour at .vitaoteygd, seve sten bo bosom ae Mewoteteve. coun ovivrve nao eartel, edd Bo eats OF ait sande bid enade gnitites ei) Sopet Sins away Aedes fenton « eRe Bi is etn lwo Hidefuyor cool dome te eavitnl an‘ ertha one Rien Bat iute mer OE UM OD i PT ? { cory Vite tI ue Bt di — “nbnag hal tO one t Jach3 eulend ay ac agnor rake Bs & ae Sig 6 B®; Nahr hed etude toned ts bys {BOSS AOS? m “ eitogerad GE doolinteay LLeta o ike Broan ha BA: 50Ouh ct a} ae al a) sisi BO AO OEE» ms Although it is clear that, in general, the rate of growth of larvae decreases with a decrease in the temperature of the surrounding water, nevertheless, it appears that a combination of several factors may be more important in determining the length of the larval period than considerable differences in temperature. For example, in one of our recent experiments the largest part of the eggs obtained from the spawning of adult clams was placed in an outdoor tank, while the smallest was cultured in the laboratory in a regular hatching crock, At the beginning of the experiment the temperature in the tank was about 19.0°C, After ten days, towards the end of the ex- periment, the temperature of the tank water showed a slow increase approaching approximately 22.0°C. by the 14th day. The tempera- ture of the laboratory hatching crock was, on the other hand, quite steadily maintained throughout the experiment near 24,0°C, Yet, regardless of the lower temperature in the tank, which, during the first ten days or so, was approximately 5.0° lower than that of the hatching crock, the larvae there began to set on the 14th day, while the first set in the culture crock was observed four days later. Cbviously regardless of the lower temperature in the tank the general combination of the factors there was more favorable for the growth of larvae than in the laboratory culture crock. SUMMARY 1 - Larvae of V. mercenaria were grown to metamorphosis in four experiments at the constant temperatures of 30.0, 27.0, 24.0, 21.0, 18.0°9°C. = 1.0°C. Observations on development of egEs a prowth of larvae were also performed at 55.0 and 15,0°, oe WAKO} e 2-=- The size of the smallest larvae found was 86 x 64 y, and the largest, 256 x 228 hy. 3 - Within the temperature range of 18.0 to 30.0°C, £ 1.00C. the rate of growth of larvae was generally, but not always, more rapid at high than at low temperatures. Small differences in the temperature, such as one or two degrees, or sometimes even more, were not as important in affecting the rate of growth as was previously thought. 4 - At the temperature of 50.0°C, setting of larvae began in some experiments as early as the seventh day after fertili- zation. Setting of the entire larval population kept at this temperature was accomplished within five to seven days after its beginning. 5 - At the temperature of 18.0°9C. the earliest beginning of setting was recorded 16 days after fertilization, and the 94 | he Henne i Mom Ate LAPS Cle eae ers Als adwoxs To ofe+ eft Lersnen at ,tadt teefs et 41 dsuodata edd to emisieqned eft mi eeastgeh 2 dtiy eaéssetoe 6a @ottanidmoo a said essoqgs J! ,ceeleidtoven today gt Pas anininirsseb at dnadtoqmt eto ed yam stosost fat Mh econetettib efdasebiencs madd bolaeq Laval edt. td Ome Binontteqxe ¢gneost tuo to eno al ,efquexe 10F ¢ ‘Viube to sainweqe eft mol bentetdo enno edd to jaaq # esw Jeellems odd efitw asd toobjuo ne af beoalq Ban $A .Moow aotdotad aeliget s al ytotatodal edd al B anes eld mt emsarequed edd inomtteqxe ef? to yatnake *xo oft Yo bye edd ebhiawod ,ezab net tettA ,9°O, 08 £0 epaeton! wole # bowods totey wcted edd Yo emsareyied sid 3 eprtccried oT .yab dsal ed? yd .0°O.S8 yLlesantxotqca gnkae Haiad sredio edd no .,eew Moot. aotHhotad yrodatodat ols Xe 2999,28 cs0n snenitexe edt sxodguotis ben totalon eitbaeda. efotiw .ines odd mi etusateqmed tewol ot to eselbuags tewol °0,0 yfetsmixotggs aaw on to eyab net text? eng Yee of aeyed etods eavini edt oloore ynidodvead edd Be Sasi saw Moots euitinm edd nl toe dent? add efisiv .7eb aabEy fowol edd to exolhteger ylewolvdo .iedel syed “WOT Be etojoal. aij To aolvanidmos Laetoneg oft Anat od al stem odd mi narid eaviel Io diwory add tol ef[datovel ston Bap eMoo19 etl vo Views an . XFS od 1 Ae 4 ataorqiomagyem of nwoty etow altsnootcy .Y to osvaal ae eOeTS ,0,08 to setedarojue!t Jausitnos ed! ta ctnomtteaxe § So Jnemgofevebh no saolievised2 .9°O.f & ,.9°O,Sf Oe e0°O.ef Ban 0,05 Ya bentotisq oefe otcow savaiel to Aswo ba ¥ * i ° Pe i , gM #09 OG saw Orvot eavtel seellams of’ to esta olT » § o%& SSS x SSS ,toontel ae 000, 5 2 .5°0,05 of O.2f ‘to eanat omtateqnet edd ntadiv = & ‘ e@cewle Jorn aod avilatenen sav oeveal to dewory to 9 Gesietetiih fame .cexwieveqied wol ga nats dnid Ja Bigee Gomivence 19 ,oeexpob owt to emo Ba done ,etidaTeqmed ae Aswory 1O eat oid yoliocette m2 dassuoqm!l ea Joc otew .etGnam eteinvods ylssorvety saned eavisl to aniities .9°0.08 to erutareqnedt en? JA = Bo eliftide? tavte yob cineves edd es ylase se stnomtreqes elit ja Jqext nolteliujoq Levaal oxlinge odd Yo gaissee shake tedta Byobd sevoe od evil middiw Doisliqmooon eav esuseqtege snataatged | gitacined Peolfree ont .9°O.8I: to etudateqme?d ad? Gs elt bas ymottaxsiilidet tette exseb Of bebtooedt baw gat ae latest, 24 days after it. At other intermittent temperatures setting of larvae was within the bounds indicated by the two ex- tremes. 6 - The length at which metamorphosis took place ranged from approximately 175 to 236 yi, occurring most commonly be- tween 200 and 210 ym. There was no indication that the larvae grown at lower temperatures were reaching larger size before Setting than those grown at higher temperatures, 7 - Larvae which came from the same source and were kept under identical conditions showed great variation in the sizes. In some instances the length of the larvae in an old culture ranged from about 100 n to that of full grown larvae measuring in excess of 200 n. 8 - The length-frequency distribution of larvae grown at the same temperature but in four different experiments showed considerable variations. These variations were found in the range of larval lengths and also in the lengths of the modal classes. 9 - If, immediately after fertilization, the eggs of clams were placed in water of a termperaure of 15.0°C, = 1.0°9C., vir- tually none of them would undergo normal development resulting in the straight hinge stage. However, if the eggs were kept at room temperature for nine hears before teing subjected to the pore temperature, some of them would reach the straight hinge stage. “4 10 - Eggs placed soon after fertilization in water of 33.0°C, - 1.0°C, would show abnormal development and heavy mortality. However, if after fertilization the zygotes were kept at room temperature of about 22.0°C, for about two days and then trans- ferred to the higher temperature, a rapid normal development of larvae would follow resulting in heavy setting. 11 - In general, the experiment showed that young cleavage stages of clam eggs occur within a narrower temperature range than the later stages. 12 = The color should not be considered as a distinctive feature to be used in the identification of lamellibranch larvae because it easily changes depending on the color of the food organisms eaten by the larvae, 15 - Auxiliary experiments showed no evidence whatsoever to support the contention that organic detritus is a better food for larvae than living phytoplankton, such as composed largely of Chlorella sp. Two types of detritus, one composed mostly of dying and decomposing plankton grown under laboratory conditions, and the other collected from the bottom of the tidal pools, were fed to the larvae, but caused their slow starvation and death. 95 aes Ag UR OI ON a ae | “once ticaes "tosatodal tebay owety aoddaaly Bat soasinne 1B ae hp apuetapeace? dnetiinweint tedto tA «it teste aval “xe ows _@f3 1d betsolbal xebased ent akddte aew onv beznas.sonfy.dool slesdqromedem roftdw Ja qd? met + “ec yfmonmoo fdeom aninayooo. a: 868:-0c ONL x etantxe eevisi oft dads aofiaotbhal on sew etetT .m OLS. ba; etoted este senief:. antdose1 stew sewwtaroames: sowol #2 etetusaneqmed sednid: te nwory ecodt omdd® dqox -orow ban eotwoe emas- offd mont omeo dotdw savted - eseats efi at nolisiasy. Jooty Beworls anotdibnoo Imeltine omsivo bfo ae nl eevrtel ed: to dinmel efi @eonatent gilguesem eavial nwoty Ifvt io ted? of ~ COOL suoda mort; ae ae ¥ a ta nwo; eaviel to aoliudintel!S yoneupoti-itgael en Bewete etnemtte¢xe trenettib tol ml tud etutasteqne | om ed3 af Dawot etew snotiaiuay etedT .anotiaiday: oldat a fabon ect to. midgnel odd at osle bae eddaneL favasl ° amelo 16 enne.ed? ,nottestiidaet setts eehaatbanst Mp > -@ tiv ..0°0,f = .990.2f to etmeteqmiss 2 to tetaw at beos, gatityoos Geatoreveb femton on tebas Sfvow medy to pe Roe tqoX erew enne eit tf ,rsvewoll .enate egaid Jdnleqa) ed? of Bbojoeidw:e nafed.otéted atest. oata tot oud ated a enaid sdgtesie of3 dosaot Gluow medi to omoe ,otudateqnsl sOPO,88 Yo tosaw mi moldastftinet toftea moos besatq agad = 6 etPiindtom yvaot Ine dnemqofeved Lantonda wods Bliow so moot in sqeud otew eotonys off nolsastitiast tesie Tf pie eanetd nei? baa evab ows jucda rt .090.88 duoda io otulAe to ¢nemqofeveh Lemion biqes ,orudstequed tetagid otf ot_bt egiiiter vvaAeid “nt: nalifweet wolfot biluow enAvecrs nutoy tadjy Hewordls bag 5 re ed? ,fatenes al.e Ef Sanet exideteqred rovorisa a aldifts qav990,enno malo to” sconate totol ef ‘ . On evitonitdetb 9» aa betebilensco ed gon. biuodts toloo aT + of eaevtal donsidiflLewsl to.molideoltitnebl edd al beeu ed oF eames % et Yo tofo orld: ao anlhneqeh eognedo yfisae df eee epovist wit yo aotee enalaé Of tevooedsaln eonphlve on bewode etdomineqxoe yaatlags «+ Pra.) Boot “1etded a ef autiadeh elnaste Jedd noldmetade edd drome srcties begoquon 2a douse gnotalnalqosycta nakvit aed” oay za gs0m Sesogroo eno ,eutinseb to eeqgd owl sag 4 e1ew-,2logq fubld ens io .mottod. etd nowt betoelfoo sedge. eitaeb bas dolinvints wols:atledt becuse tud. ,eavasi: we: ses! 14 - The degree of aeration was found to be unimportant in affecting the rate of survival and rate of growth of clam larvae, Clean, carefully attended cultures could be brought to the set- ting stage without continuous aeration. 15 - Overcrowding of larval cultures of V. mercenaria is not too easily achieved. Our cultures, as a rule, contained 50 larvae per cc. of water, and several cultures, in which the con- centration of larvae was more than 100 per cc. of water, were grown to metamorphosis. BIBLIOGRAPHY Baughman, J. L. 1947. An annotated bibliography of oysters. Texas A & M Research Foundation, College Station, Texas, pp. l- 794. Belding, David L. 1912, A report upon the quahaug and oyster fisheries of Massachusetts. The Commonwealth of Massachusetts, Marine Fisheries Series No. 2, pp. 1-154. Coe, W. R. : 1948, Nutrition, environmental conditions, and growth of marine bivalve mollusks. Journ. of Marine Research, Vole, NOs 3, pps» 586-601, Korringa, P. 1941. Experiments and observations on swarming, pelagic life and setting in the European flat oyster, Ostrea edulis L. Extrait des Archives Neerlandaises de Zoole, Vol. 5, pp. 1-249. Loosanoff, V. L. 1949, Method for supplying a laboratory with warm sea water in winter. Science, Vol. 110, No. 2851, pp. 192-195. 1949a. On the food selectivity of oysters. Science, Vol. 110, (Noe. 2848, p. 122. Loosanoff, V. L. and H, C. Davis 1950. Conditioning V. mercenaria for spawning in winter and breeding its larvae in the laboratory. Biole Buil., Vol. 98, No. 1, pp. 60-65. Medcof, J. C. 1939, Larval life of the oyster (Cstrea virginica) in Bideford River. J. of the ish. Research Board of Canada, Vol. 4, pp. 287-301. 96 MY ip CAO MINT si) uU ae Hi a | eae od of - Sauer one devine to- ne : oe art malo ‘to diwory to etay Baa Lavivwe to edat 9: _ Stee: edd of thguonf ed bluco eoidiiuo hbebnedte. yliute | - ,notietes asopatinos tort be | oat. : «VY to sotutivo favaal to antowototevo 3 me ber. ‘avnoo ~oiu 2 UH ,eotuILLO To: sbevetdoa. viteeey ero0 eid dotdw at ,eeiuilivo [ereves bae .teJar To .99 tq Stew |, tedaw To Oo: aety OOL anand etom zeeaw cevast io- not ae a -v RABAT. O L18 Ed ~ gall ah oe sored eyo 20° Wo eaist ees Sogatonns af | od ,#exeT ,actve7& ‘epellod .¢ 325 . @f Bivad ysactanp ons “goers tr0ce% Ae: oa) ssdenmonens'l _» pee soaee ar de brig - . . ke Agworg bes aptoddsbnos ladriotinott vae- tol lado Ou & »,etdsllom evievid on kis ef99-d8E .aq ,& .of fT .foV os * rt ho aaa gegis eter Sys jolt ASO] O THE eit al nalddee Oné etl var yeif_sevitons ak i ae eee stew diiw yioletodel a yalyliaqqus “0 bdri tou .s hee eGOLHSOL eoq ,feS ,oli ,OLL -fov.. 2... eamtolttoof{os | »SSS-fSS al Oo % Be sdely «1.964 ,you expeqiail Io saviet- ‘eulevid = ee Gad. odd QV, of lt cphgnad, 3¢bas0d f tenn) motte? eniazem to ynofooe favaat: haa evisoubo rel eOdoL «aq .G8 «IOV sol sfols ,»sesenfottovas