es es} — =i ee 2 ty Bas S %. er eee ee eee vo ee bin e Regetay, wie Mpls 5 Lea Bad. rer iit nol Meng es first an ‘oN OF toe tet ee We 1% ya testis tek? 9 dnt ete ‘aoe, pete Berke ow ee . ache at) rae ay | 9 tea TL 5. a 4% Bü Fene 125 7 3 > russ el da eran « era eis te ie 40 eg men ob an. xcath acer e Fe ey ed un Ke of ing 0 0 wetter. oy Ae ee tds 743 77 tev bitow edd sundiwordd ent wot on . Ot Be, wordt t eteh Of womty basa ti bete e Ss tude. Bee Deatwe tegen meg ee enn ssen Lace eech Be pap are “yas. .vichass 103. , bout sha Stak ee Lasoo, fog ‘tants wry obus e ee ee a i025, giao ‘Pha 105 * Grace | Bist at Bao. 1 7 ites eee rb a ie wis ae ‘yee ss ett bo aks ode S rh edits eee bl ee ite Ty CEL. bol one evi len 2 tf e vondc een ee een ei Tt ede ren : & edo On 2401 ova) ee Ylovienbere eee eee ae wad 1 2 He Aste eee OT e 1 86 Te 5 out 80. det Set rot sort evew etna at? tus deals mt tagel we Hanwae Saen nase gas 3809 abo At tes deny g Otay eee een eee do eee e bet a edt Pepe de No done evan : pes oh eg De anol an fo d tom 4 8 ae ain were set ee Ye pve ape ‘weil ‘3 0 aki aHE Ys haste Tate fiers stare) An bers wrt de Nat mg 1 rent oat ody earg iche 4 2 * tee. „Se 88 ec Ros Toy 0 15 iG oft en royty ‘Boelte nog 10 ston gmt 92 0 il te ttt made 8 an es 3 WEES att src on DEH ien er aT e * 8 doch an, ee re i 800 i cet fat ee We e pie thaw evn „„ S4p secinodetey savohyd eft “ahi ems ‘ty eee ‘ory e ö Stabe god i) eee Sec Bg i Gt Yau 71 Vale ag Ane ns ar yao eee odd at p Gren viteot s “ft So Yaod ade wh eie ele mMn Us el 8 bya ton Ang growth in trout. Ry Novemher of their second year he had same fish up to fourteen inches in length as against a maximum of seven for the unselected general stocks. Dr. Carriker, later to appear on this program, together with co-workers in Wisconsin, developed a race of the common fresh-water snail, Lymnea, which was approximately one-fourth larger at maturity than the wild type from which the original parents came. G. W. Martin working in our own laboratories showed twenty years ago that of oyster spat which attach at the same time on glass plates where they are able to grow without obstruction from other spat, some may grow as much as three times more rapidly than others nearby. Confirming this are these two oysters of the same age from Nyatt Point, Naragansett Bay, Rhode Island, which T am now showing you. These oysters were on the same bed, subject to the same conditions. The smaller one repre- sents a good average for the oysters as a whole which were remarkably uniform as to size end shape. The most probable explanation for the much greater size of the larger oyster is that it was due to internal factors of inheri- tance. Looking closely at these oysters we see that in two of the years growth was greater than in the others. In these better years, however, the larger oyster made relatively a larger growth than did its neighbors. In other words it made better use of the more favorable growing conditions than did the other oysters nearby. Whet do we know about the factors of size and rate of growth in the oyster? In the European oyster, Ostrea edulis, Professor J. H. Orton of Liverpool, showed in 1925 that in the Fal Estuary in England 42% of the oysters on the beds were of a type recognized as “dumpy". In these the growth rings are much closer together, the shell is rough, frequently mis- shapen and the thiclmess is appreciably greater due to greater thickness of the shells, not to a larger meat. He states that in general such oysters are from two to three years older than normal oysters of the same size. Because of the prohibition against removing oysters of less than two and one half inches from the beds Orton found a higher percentage of dumpy oysters among the small oysters under two and one half inches than among those above this size. I have recently suggested that one contributing cause to the decline in oyster production in the Chesapeake Bay has been the “three inch law" in accord with which all small oysters must be returned. Where dwarfed oysters are present it follows that their number will steadily increase since their slower growth will keep them below three inches longer than required for normal oysters. In many cases the dumpy oysters may never exceed three inches in length. Owing to the slower growth of the “dumps” a larger pro- portion of these was being thrown back on the beds than of normal oysters, resulting in almost one half of the oysters being “dumps” at the time of his investigation. Remembering that the European oyster carries its larvae upon the gills, let me quote from a paper by Professor Orton in 1926. "Although the dumps are now seen to be not so good as the others for spawning purposes, yet they are only slightly inferior. There can remain no doubt, therefore, that dumps are valuable for breeding inasmuch as a high proportion yield larvae like normal individuals. We have no means at present of ascertaining the survival value of the larvae of the two types PER ee Hi i} Of any Katt comm Bet ad ee che t Ba fo lee eee yt dant la Bens tas edt Fol nee to momtaan A Sa ee oo dépasl ab een teddagot smeared Gade mo teeyes of ee gedit) «at... ERO " getow-deost gonmos adt t6 asex 9 bogofexwd. ,aiacodekW ah nad ytituesm te Ka FF elite , Aae siti all r e .cmeo dtiteteg Tana vide a e mort I ae tee Gage toteye to eee ops eee ve) awe Gawods Soros ade et We wins ot. dide ote yout etedy sci aal oo ae e ome. br ytbigat stom e ame 000 un eum s N Va ⁰õφ e aig . anke new work ose ee act ‘to d out sands erg elit 2 etodeyo guodl ly widwotle wor ms t Motdw .boeled e 4 tte oorgey ong talker on .adekvisioo saue ont oF “toot dia. «bed oma. ode 4 ‘meg hian vivedtames atom dokdy elodw a a9 Ace ze od tot dene ve boch ee dim e not ge Ses c ee er 94 . der to ene Isatetut of enh wow dk tadt of decane ‘nwgtad. th ‘ eisey edd ‘to Gy ot feds ese sw exetayo onsen 2B ‘Piensa. ity edt” Saverod eee tested cesd? al’ serodie odd at oad? ; OL. s@roddgtda ett Bib nade nen nearest 2 tievitelon obo 2 4 Keay Sd nod satwory eldetovst S0 nt Wo enw 167 0 „ . Adasen ens BASS „ SAE me? cen Te star ban ts to dees ent tyove oi “Xo Hote LH st teeke tnt yatliude uta ig LADUE de mek oc te Hb bas lan pt wronged Tat on? ak godt 280t nb L Ke „ ot eat u ene na eee eee e Yo stow 2 sels eden e st eee silt eee Tus Aoum ne Ae ache e teteots os sub nase ¢idatosaqae al es 1 dak axitayo. iG Levones ah teks sogete SH «aon teats @ oF r ged weblo mraey 6 ond Ban Get ged? peel to stoteyo pabvomet, dentays. ace “SNe eee To eee e e aer mond bod. _evods eee eee npat modo] ‘tlad sno bae d te eft of Beveo N tabs ato todd Sotdayaua 4 moder 00 Kon ane ont) 4980 and Yeh cheeqandi) add at gots betiewh n Fan of een eteteyo Lita Ti de Senta neren ylibsaty L N Tiedt Ke b 3 der ivps* ad resnol eedont sendy woled madd desk LL obne Bess Yevec Yam erathyo gah edt ee ee CCC pane aye Lemon Yo nuit abot eds fo goad. n to e edd te ee la 8 San to: phony vu! 5 selgase * * 1 tent wit he vo Ago pit as boot ge on ue of Kio es ered? eee e giddatle e di donupont grtbuerd 26% eldauls de ened On eves OW a nz Lap sr vt oft To betel edt hal oul: 2 57 of oysters, and on the other hand no substantial reason to doubt that the larvae of both types are healthy and will produce spat equally well under favorable conditions.” May I emphesize that Dr. Orton judged the spewning ability of the dumps solely upon the numbers of larvae on gills which were only slightly less than in normal oysters. His conclusion that we have "no substantial reason to doubt” that the larvae of the dumps are as healthy and will produce spat equally with normal oysters is contrary to everything we know in other animals. In the European oyster we have the great advantage in that prior to being shed into the water the larvae can all be traced back to at least one parent, the mother, on whose gills they lie. The fathers are unknown since oysters are not self impregnating, but the eggs on the gills are fertilized by sperm carried in with the incurrent stream of water. In Orton's observa- tions there was an equal chance therefore of sperm from normal and of dumpy males fertilizing the eggs of the dumpy mothers. Assuming that Orton is correct in his assumption that dumps produce es vigorous lervae as normal oysters, it is probable that at least one quarter of the larvae on these beds came from parents both of which were dumpy while one half of them had either a dumpy father or a dumpy mother. It is most unfortunate that Orton did not examine these oyster larvae microscopically. In Barneget Bay, where most of my own larval oyster studies were carried on, a thriving industry practically disappeared in fifteen years. During this period the proportion of slow growing dwarfed oysters, which I class with the English dumps, steadily and rapidly increased. Coincidentally I began to find many swimming larvae in my collections in which the shell showed numerous wrinkles and was greyish rather than transparent. Unfortu- nately I did not photograph any of these larvae since at that time I did not suspect their possible significance. I have no proof that such larvae came from dumpy parents; I can only report their presence correlated with a rapid increase in the percentage of dumpy parents on the beds. The larval broods which contained large numbers of these wrinkled shelled larvae decreased very rapidly in numbers with but a small proportion of them reaching setting size. In other animals as well as in plants tallness and dwarfness ere in- herited as definite characters as are also vigor and rapidity of growth. We are justified therefore, in assuming similar inheritance of these factors in oysters until definite scientific proof is obtained. The rate of growth end the size attained by the Japanese oyster in the Pacific northwest is known to all of you. The shells on exhibit show oysters eighteen months after their importation as spat to Olympia, “Washington. The meats of these same oysters, some of which I shucked immediately upon arrival from the west coast, ran eight to the pint, sixteen to the quart, or at the rate of sixty-four to the gallon. Dr. Prytherch has called my attention to a note by Dr. Bashford Dean in 1903 that he found in Japan, oysters weighing with shell four to five pounds not infrequently. Although inferior to the best of our own virginica when eaten raw, I am informed that in at least two respects they are superior. If cenned when in their prime in May they on dusts te arab ag ‘HONGO eien ole 46. Wackpe 0 ebe shut rat Aerts. ae eie 5 MAD Cera 5 ee Ran exe. Gis Nat dere vetted Sat plait bt. ou, 3 . Mody a n ce, ee bed poate, Ona 4 fied 1 175 ad uae Gy ab dant sn. WE,” arbi aI aL, + wine 4% O's Werth a Ae) aay, asd teat, . il Yea om shal N N e a) . Wee yarn te ar, sat 8 ita st a ‘eo tied tn oF dood Sysard ad Lhe PURE e oe etait gh: Am. yl Dehne pie “altia. Oy i ene adi, ; wearin ee ed . adnan 0 e U ‘pen Se: bein Ae en 4884 fone ae. te eon 6 at tage un, e ee Ces e ee ‘fener Se dee ace e 8s vaulboug nee te horas Oh wins go persed ‘ond , to xe wna bar, Wege d dest gos ; . he. ba # ORD, e ewe e de e Re toe e N eee yates 50 * a! e ‘gators naade ee, Fan O20 B age See eee dartel Swe e LS Laces, c wee tae ane ee he ae Ape ale janis ib eee eee e eee ö eee i eee ee an wif. A ed: at ed * aid seat? eee Bet. Ken MEY e hb T pty vege Io gone Se o iy . ee parted - EL soa? therty- n apa. } * el Hes eri. e e whos 7 PE e IER 9 0. e Marten 3 1 a e deutung Hoe x wry Py ea i ert 146 i dear f are reported to be free from the oily rancid taste whieh often develops in Our eastern canned oyster. When rolled in dry bread crumbs, sprayed with olive oil and baked for five minutes in an oven of 450°F. they emerge brown as chestnuts and cooked to a delicious turn in their own steam. For such baking, I am informed, the home economics department of the University of British Columbia prefers the large Japanese oyster. If it were possible to obtain in our eastern oyster the rapid growth of the Japanese oyster it would revolutionize our industry. The cattleman takes three years to grow a fifteen hundred pound steer for market. The oysterman requires six years, or just twice as long, to grow a one ounce oyster. It just doesn't make sense, and the time has come when oyster growers and scientists should combine to remedy the situation. We know from our studies in Delaware Bay that the survivors from the intense sets on the Cape May shore rapidly outgrow oysters from elsewhere in Maurice River Cove. Samples on exhibit clearly support this. During studies of vater pumping it was found that two-year-old Cape Shore oysters could outpump cight and ten year old Barnegat Bay oysters by two or three to one, thus giving evidence of their much greater vigor. Frequently the survivors each represent the one oyster out of 630 spat per square inch which reached the end of the first year. The others were erowded out and smothered by their fellows. As yet no one has bred exclu- sively from such fast growers and proved that they will pass on this capacity for rapid growth to their offspring. May I suggest, however, that the im- provement of New Jersey stock over the years following the introduction of southern oysters may be due to this very vigor. The imported stock which I have seen is mostly bunched with many long "cat tongue" oysters among them. #8 such they are of little value as market oysters, but being the survivors of heavy sets they may have passed along to their offspring the vigor which they themselves were prevented by crowding from exhibiting. My only first hand experience with the Japanese oyster was in the early nineteen thirties when a bushel of them were tried out in Barnegat Bay in the hope of reviving the dying industry there. During the first two weeks in the bay they grew nearly three quarters of an inch. Then they stopped growing and gredually died over the next two years without showing any further signs of growth. It must be noted that salinities here ranged from approximetely twelve to twenty as against salinities of over thirty or Oceanic saltness on the beds of Japan where Dr. Dean studied them. In addi- tion to these low salinities these gigas oysters in Barnegat Bay had to contend with the very factors of stagnation and low oxygen which were hasten- ing the destruction of the native virginicas. It was, therefore, by no means a fair test of their ability to survive in Atlantic waters. é#nother oyster in which I am deeply interested is the dustrali en oyster, Gryphaea cucullata. My good friend, Mr. T. C. Roughley, undertook to fly some to us in New Jersey last October but his plane was delayed in warm weather at Hawaii, so the oysters having been out of water for nine days without refrigeration were eaten and enjoyed by newspaper men and Others in California. Mr. Roughley tells me that all Americans with whom he hes talked in Australia claim the superiority of cucullata over our own virgin- ica in flavor. ets a dane b mathe tte lein dee benen ee ‘ott wart: wth wien ditty deyorqe jodavio beerd Ee at holier wet eee eee, | CNRS eee yet ee to ovo ne at een whe 204 Bad nea 0 6 fone cok eee e hot) e u eee , a bonn one e To Nobel eee eee eee andi edt eee e we 4 oi tenen e oF Sz he e et ee Teng b Wien ‘kt ee eder oft to een bined oud ceteyo ror % oT os Woy Ot ee eaxds we eee ee of? eee tum ee et, 56 eee Xin eotdupet seametayo ofl. e pig py bie. genew even eee gaut a. torayo n ene 6 b of agiitimos Bondo este en oa exewot, Tad a atoviveie ont todd git. Ptaweled at sothuta. ono 1 ö MORE e en e tnt exode Yall oe? g nb e Sroggie lee eee wo eee ee . e a @ COLORS oye? PLornpoysout Yodt paiicd enw th eee dete to eet ö det Yd eee Yat roset u blo nö, set baw Mgt! ben tyo HU only W tome d 0 manebine ee ee vf tone: coy to. 20 ih es HO one Fameerqerc use hv, ede eee eee ort? ee teald ost to bue eft bodeeet dba 2 -ithen Said end ono on toy ek te Ale xd. ig me tn UW looges eit Ko peed II ven ted dern Ja erowory , th wit teks yrovowod ,Seognun { ye eee shady of are e Be he et eee ieee ee edt cows doors deen wort % eee Meese botroumt pal .cogty view atét oF oth od yam age at tons aN uno tas" gaol tt an hedoanud Mean etn ee een eft gated tod yaneteyo textom wh onlay e To one, wird ana e ad? e n ee tient of guole boeesy evad e Wout agen BOLT id tino wort Aer * ben orem ae W E +" A kürte we at * Abts @odteqsl, ait. mil nee bond an BE yet eee At foo elit eee we to eee 6 ae ee | ne Ow? Tae e ont gobi ee, ytawbat aur ely ee 1 eaany heqgote Vea nod? „nt os Yo ated soup sotdh een wary Nace yee ‘eis kw gaudi at Sent ows e edt eee ee dünn un; mot panies ond Gatten Jett ben a of tamm #1 en to Boeke © HO. Nele r to ald Nan oe Vaaene ot pe Bh oe -The GY yaad? bothdan need wad ovedw ce, to ee one RO. N _ otf ee le eee ok ede eeats cee e ee e @ enetend enon Aeta, gc wot bee cottenyate, Yo azotint ytev wie n baa Gee on yd eee ee yhow n «tyotokyrby wvitet afd Io eee 1 ; e oN fq of n of mile e 2 a voter ws tobe tas, o oh boiteonathe vfb me 1 Aar 1 oi BLE Of Accs zabaw, tote ut oD et ATA SHG LET Roos, vw pew a: heyetobh aay onehe aid ded 7 ih wags, hah gh avs ents 40) qwitew to #40 Mead Aten eroteyo edt 6a | | at cane baw con aan UE beyotme Hie ae ee een e den od mode Hiaw dec Lo toute am See deen «th ee -nhytiv wo tho 40 otaitwaut co e ed mole NA 1 What the industry needs at this time is a thorough end unbiased study of the more promising foreign oysters together with errorve to hybridize them with each other and with our own 2astern oyster. A hybrid with its increased vigor should grow to full market size in two years thus enabling the oyeter planter to turn his money over three times where now he turns it over once. All such work must be conducted with the greatest care in enclosed basins in a laboratory whence no enemies nor inferior hybrid oyster, if produced, might escape to an oyster bearing region. All waste water from tanks holding any foreign oysters must be run into a sand pit whence it wiil eater the natural waters only through the sand, or the waste water mus be 4reated to kill any life therein. Our industry is far too valuable to take any chances or to trust to luck. The virtual wiping out of the superior European oyster, Ostrea - eu in France by the accidental introduction of the inferior portuguese oyster into the Gironde River about 1870 furnishes a vivid lesson to all of us. The giges oyster has already proved its value in the Pacific Northwest. Dr. Prytherch points out that Fisheries Statistics of the Fish and Wildlife Service for 1941 shows that from Washington, Oregon and California over twelve million pounds of these oysters were hervested in thet vear with a value of seventy-five cents per pound as compared with sixty-three cents for the small native lurida and forty-one cents for virginica raised out there. Such figures do not support the claim of inferiority. ‘There are undoubtedly areas of high salinity along our Atlantic seaboard where the gigas oyster would do well but where the lack of fresh-water reterds the growth and fattening of eastern oysters. We are taking a short sighted view of the potential development of our coastal waters if we do not at least consider the possibility of introducing into such areas an oyster which will thrive there. 2 Suggested Program 1. In all areas dependent upon seed oysters produced under the care of the state it is urged that spawning sanctuaries be established in proxim- ity to the areas to be shelled. To these sanctusries should go the largest and most vigorous oysters available. I am recommending in New Jersey that the funds available for spawners be spent to buy back from the tongers and dredgers the largest and the best of the oysters as taken. el ——— rong To % co at a e M e 1 ovit Ae chee 1938 „ bo a 2 e Che see 1937 3 . „ N s 30 „ O38 a2 Soe a 1936 4 W 5 oe — G98, 35 e i ke togee ee e e ee eren, e ee ie eae The year--class of 1935+ consisted of oysters the age of which at the beginning of the observations ranged from 5 to 10 years. 3 ey „ el r ie 1ST ae been 52 | tu ou} 7 hs 55 Ine se ok HONIG, BRBETCO2 Oh 7% Ter su TAs” hy ED — Tin am * i Wi ae. Ok. N re = 8 = os Aue * eS * ee | Ok BME Diss N 7 5 e. ee a 3 5 — 2a a 1 — ; = g — f . * f ey = = “apie 8 : same ae] — < — “ iy." D Lf Tats: 5 r lived at least through 5 growing periods. Their age varied from 5 to 10 years. The majority of these individuals was 6 years or older. Such a heterogeneous age-group was formed to study the growth of a mixed population of old oysters, which are usually used for stocking spawning beds. In these studies the age of the oysters is based upon the number of growing periods completed. In Connecticut waters the period extends from the latter part of April to early November. Since in Milford Harbor and Long Island Sound e new generation of oysters usually appears in the middle of summer, its first growing period, confined between the date of setting end the beginning of hibernation, is shorter than subsequent ones, when growth continues from spring until autumn. Nevertheless, the first growing season, even if it is of short duration, will be regarded here as a complete one. Therefore, the oysters which have completed their first growing season will be considered here as one year old; those that have completed two grow- ing seasons, two years old, etc. This method of age classification may be different from that employed by some oyster growers who consider the oysters which have completed their first growing period as “set”, those which have completed their first and second growing periods as only one year old, etce In such instances the age estimates of the oystermen will be one year behind ours. This discrepancy can be simply adjusted for the convenience of the oystermen by subtracting one year from our age figures. In preparing the oysters for the experiments their shells were cleaned of all foreign growth and then the greatest length, width and depth of each individual were measured with the aid of calipers. Measurements were ex- pressed in millimeters. Later, the volume was ascertained by using the dis- placement chamber method. After the oysters had been measured they were placed in large wire baskets, which were suspended from a float anchored in the harbor. Each year-class was kept in a separate basket. annual determinations of the increase in size were made each autumn when the growing period was over end the oysters were entering the hibernation stage. The initial measurements mace at the beginning of the experiment, in #pril 1940, showed that the most significant difference in sizes existed between the youngest year-class (1939) and the class composed of animals one year older (Table 1). The difference diminished when the older groups were compared. In the two youngest groups the difference was especially pronounced in the case of depth, or thickness. The mean depth of the 1939 class wes only approximately 3 millimeters, as compared with 20 millimeters shown by the group only one year older. Thus, the mean depth of the older (1938) age-Class was almost seven times greater, while the mean length and width of the same year-class were only about three times as great as those of the younger group. Obviously, during the first growing period the increase in length and width progressed at a much more rapid rate than the increase in „ ; e be übe ie on cd wee Be 0 e ee e i ws 6 Rete ene eee eee ach te rc oh „ee vs eee Fork ude J d t ell b (dem: gate Feen en e eee al ee ee eee Face endes In aeg e eee een syed n G een een eee eyed Seid eee ee ee oan ae ee de- l AME „ 0 ‘so * HPs 2 5 W bene 1h me en Yo ben edt \ Ber Kate cee ene att eee to | %% anioatged Bat , eee eee henry ; it Mg Bd eto een ont oe Yam eee eee cae ‘bo Better meee 100 1880 San rage „ oye it dene odw M6 Weng tedeyo umow 0 Have Le feat ies 1 Rear see es eno bet kin eee ade Wo e ee ie od Sd aM west’? e U M ene green (ows 3 0% etter Anes “ton we eee eee ee e Did eee wo ee os ahobrog aniwuty bacoge bee ttl ote Re aisha ini and 30% Cray e eee ve ste cs N . eig e Whe e Tey one, Wee 6 e . attode Aloe athuyenkttecss oat 40% AG n Aal hone to ute Bas A eee tentaots ont mope Bas dewey Me iio etew atuementesdlt ee s to btw edt thw Bextewom ee oo ode dated vc bopletavous: enw onunlet nit rated’. .cxoremhh iin sHodtais ag, "anew pve “ak beende roc. weng Beru dent haat et Se mie, itor? cel oat ab Sexodoos tout s oot bah ö ee To eee eee eee eee eee is dr N Sake i ee meets Ae e N ont . nen ody te ue ee ere Boge ab eee n tiem, eme 80 dun : ue mn i ial i eee 2 Ytotone ‘oe 6 4 mew wood CURL ont to: e ror out ‘| one ott he ee ee see atl wait ne Ae e ee old, gal ite wet Yo Ahoy we tHe By * ur ebnet edt Beere k on en eee ott ad e erie 15 depth. During the second period, however, the increase in depth proceeded at a comparatively greeter rate than that of the length or width (Tables 1 and ihe TABLE 2 PERCENT INCREASE IN MEAN LENGTH, WIDTH AND DEPTH OF OYSTERS OF FIVE DIFFERENT YEAR-CLASSES DURING GROWING PERIODS OF 1940, 1941 and 1942 MILFORD H..RBOR INCREASE INCREASE INCREASE YEAR- AGE _ DURING 1940 Ss DURING 1941_ DURING 1942 . Age IL. W. D. Age L. VV. D. Age Lo Ww. D. 1959 1 year ? 8 45 38 30 4 10 6 15 1938 2 years Oo Sou too) joo & 1 AS) 1 5 9 6 9 1937 3 years A AES Ae, DB. 5 „ 8 10 6 9 1956 4 years 5 9 8 6) 46 Ee eS)! Oey; 8 8 5 1935+ St+years 68 7 8 2 a A eS See 95 4 5 During the first season of observation the greatest percentage increase in size was shown by the youngest (1939) year-class which was then completing the second growing period of its life. This increase was 205, 221 and 567 percent for the length, width and depth respectively (Table 2). It was sev- eral times greater than the percentage of increase recorded for the 1938 class. In the latter case the increase in length, width and depth was only. 57, 53 and 33 percent respectively. In comparing these two groups it is interesting to note once more that the increase in depth of the younger year- class proceeded more rapidly than that of the length or width. The three older year-classes, including the 1935* group, also showed an increase in all three dimensions. However, the percentage of increase became progressively smaller as the age of the oysters increased. A the end of the second vear of observation, 1941, the most outstand- ing fact noticed was a pronounced decrease in the rate of growth of the 1929 year-class which had just finished the third growing season. While during the preceding season the increase in length of this group was 205 percent, it was now only 45 percent (Table 2). A similar decrease was also noted in the case of the width, while in the case of the depth it was even j N ean 5 fh ae ere Gert, * 4 a N V4 * en 1 A i ve 1 bebegecg atqob ut — ould e beta nee. es. ead gene — e Wonne orang y rid gn = sseetont ge fed teetaetg oft uctdeavteado to doaaee gate ‘med? saw dotdw agslo-reoy (eder teogmicy e | Bite n GUS sow ere bn ofa? eL att to Dok 18 e100) vleviteeqeet Hrqeb bus ud en 800k dc aot Bea ν,,ihaůtt to eqadusoteg ont a ghee sew on Bon dtbhiw tene cl een oft & „ Be gE aqvory ows wasnt anizaqacs al -ylevitoy er baited add te noed St eso edt todd e N we 20 aaa ett to dear agit 4 “pelea cuits wots see elle aakpetomt etage ne n ede eat Io enoageagd edt eo 20 a gt Sende Ite 1 2 subnet idea 9 edt to ope ath baht * adden gave ag be nee vaoade to ne 1 ec? e atwoty Yo aval. ose ct oasoroeh DLL PEAK eee satworp batty cit Gude take Beet. ; BUS ai quo vide te ee of e e de Bde ests Bow. esse rA te A I eee sam: ande cen #2 Ade ode to she ent at i 16 more sharply defined. Obviously, during the second year the rate of growth was much more rapid than in the third growing season. The oysters of the classes older then the 1939 group also showed a continued growth during the second season of observation. However, in all cases their relative rate of growth was slower than that of the younger animals. As observed during the preceding year, the percent increase in size decreased with the advancing age of the oysters (Table 2). During the third and last period of observation, which included the spring, summer and autumn of 1942, all the year-classes showed a further increase in size (Tables 1 and 2). However, in the case of the two youngest groups the relative rate of growth was much slower then in the preceding years. at the end of the experiment the age of the oysters constituting the oldest age-class ranged from 8 to 13 years. Examination of the largest in- dividuals of this group showed that they, too, had formed a new shell growth during the last summer of observation. Evidently, even those old oysters, which were completing the 13th year of life, still continued to grow. In reviewing the experimental data attention may be called to a simi- larity of the mean dimensions reached by the different groups of oysters upon attaining the same age. For example, during this study four different groups were at some time four years of ege (Table 1). The mean length of all these groups at the age of four was very close to 90 mm.; the mean width varied between 64 end 68 hm,, whereas the mean depth was from 50 to 33 um. In the case of the groups reaching the age of 2, 3, 5 or 6 years similar conclusions could be formed. It was also noted that the oysters of the 1936 year-Class, upon reaching the age of seven closely resembled in their dimen- sions the measurements of the 1935# class made at the beginning of the ex- periments, when the average age of the latter group was also approximately 7 years. Perhaps the most significant part of our studies was that devoted to observations on the increase in the volume of the oysters from year to year. Both Milford Harbor and Long Island Sound oysters were used. The Sound oysters were supplied through the courtesy of Mr. Charles Wheeler, Manager of the Connecticut Oyster Farms, from the beds where oysters of known ages were kept. In comparing the mean volumes of Milford Hysvers with those of others of the same age a very close similarity was noted. By volume determinations it was ascertained that the youngest year-class showed a relatively greater increase in volume than any other group (Table 3). The average volume of the animals representative of that class increased from 0.4 cc. to 19.5 ce. during the second growing period of their existence. This represented an increase of 4775 percent, indicating that during the second year of their lives the oysters may inereese in volume almost 48 times. Thus, if they were grown under such hypothetical conditions where no mortality among them would occur, a bushel of culled single oysters planted at the end e e enge atta ota | witonese dane Beate eat Geng COOL odd nan! 4016 . ‘So gro? ait N 4 8 Sαπα n mae ddt whom 20.4 Aoi e * e Ferny 10 * “prow tachi ut vatunah gerte ved U, net e ett we ge e Wr of Deen won ae ee so ade gahe 10 l een e 1 vet ett ot eee lee eee dee Bae de ee ty Wine uot Meg lte Eten ce t ein eee ee 1 9 Pion and 2 a. ye an OF bee bleed, " eonborg wan eh thw 5 eee hie eee We tankt We & a, alete POND e 25 Ir oa fa ne Aiea 11 eb ence on teat ‘sh ggg qidecuten, todd n att. . u ert ome n bay eee tells ee eg pd” neo Aenne eid? „ .axenoty teduyo ait ‘bite neo aa? to dso Khe ay dae E os A tba spore Sue ah 3 f al fo Saen Te one ont opbF / exstiwotey sera # DEE ee ROY ere tomate awa RORY anh dew We wd somes chet eee ered, Son e Yon Yaw en ee Bag eae dk, eee to Abe ey “to. een Yo terivtvn oft tosthe pisavoliore e geluwio ect ot Ge, Se yaad E ot Vi u, ats BO pies eee eee ent te @umioet sever .caldiag ane t Mies Soe eee e, E F device of doaRe RE Melony cit Yo Wxokame aur vite ef? -,enciasode. tinupestéf co see ht 8 gt n Yd a 8 ee rl ak nd eee hoo tom Sey „e tert ed oF lee wre ae de e e ee Gi ct need yo) en N y nee a un t eee od eee e een a aer alt eee e e ated e „ tot eee tetayo Be Jeep La ee Gas 2 080 5 8 1 Aenne e ien matt da a Sa * bros, ee Abu nee W We att iat 19 Cases of unusually high yields, nevertheless, are known in the history of oyster cultivation. For example, one incident of this nature was described in a letter to the author by the manager of one of the New England companies. It was stated that in 1906 an oyster company located at Wickford, R. I. planted 200 bushels of three-month-old oysters gathered from lot 607 near Milford, Connecticut in Long Island Sound. Four years later when the pianted oysters were dredged their volume amounted to 2,200 bushels. Thus the yield of 11. bushels for each bushel of set planted appears to be possible if con- ditions are favorable. In the course of these studies it was determined, by ascerteining the actual volume of the oysters filling a bushel, that only approximately from 48 to 54 percent cf the space in the container was taken up by the oysters, whereas the other part consisted of voids formed between them. Groups of oysters aged from 1 to 5 years were used in these determinations but no cor- relation between the age-groups and the percent of actual space occupied could be found. Therefore, if the capacity of a bushel is equal to 35,238 cubic centimeters, only approximately one half of its volume, or 17,619 c., would actually contain oysters. Using the figures for the average volume of oysters of different ages, as determined by the studies in Milford Harbor, it was possible to calculate the approximate numbers of oysters of a given age per bushel. These numbers eppear to be 44,047; 801; 383; 271 and 198 for oysters of the 1, 2, 3, 4 and 5 year-classes respectively. In the case of deep water oysters, where the rate of growth is slower, larger numbers of individuals of corresponding ages would be needed to fill a bushel. In connection with the discussion it should be remembered thet all ref- erences to bushels or any other units of volume are made here on the basis that only single culled oysters were used in these deterninat ions. The presence of shells and other foreign material would, of course, decrease the number of oysters per bushel. Returning again to the growth studies of oysters we may discuss the possibilities of applying some of the results to practical use. Of consid- erable importance is the observation that during their second year of life the oysters increase in volume proportionally much more rapidly than during later years (Table 3). Obviously it is of more advantage to oyster growers to purchase and plant this age-class in preference to any older group, even if the mortality is relatively higher. N The planting of oysters that are two years old also appears practical because during the next growing season they may more than double their volume, and at the age of five years yield epproximetely 3 bushels ver each bushel planted provided, of course, thet the mortality rate is kept at a low level. In practice, however, it may not be often achieved. Oysters 3 years and older also continue to increase in Volume, but such an increase proceeds at a comparatively slow rate. Therefore, the growers, who intend to plant older oysters should carefully evaluate whether the N ti 1 Idea Uae 5 an pom at wort ore eneked seman at iD tty ak ; oy Ra ee ene e Ta Once ater e 1 W. 1 5 ne Sy uae i Ao ee to a “at N. * eee eee ee odd de ee ho eee srl 1 BES a poet 8 't e. | (PAO ett: Ses Letened yegeru wails ee WS er enn ene e e lernen de a a wi ee tata eee een e Stra, pie) 555 pit Roan. Tet re’? elovasd GUAR od eee Mune abode Bagot’ exit wee ; 8 M eldiaac, ad ot iit Havitale tye te ange dees It Sheard fh To cee ent ge e akte rob as vd en r 9 4 „ sition * Fee dcn ee lee PANE feted a yh Cle eee mds mee ep 1 et at seen ont 3 f 5 9. bad gh 6500 e 1 e e ot bee ak eee e 299 rde 10 AA 8s 1 ee So Len art n acht e Be e UE henimmsted as ene bos 34 9 050 ct une a en ot 9 SRL bao. a 3682 g 105° 50 ee .Ladend eee ee * er to Bt — a Setteditonae ad Bb eie bK ub met a n PAL eee eee eee ot heey se Ste 8 4 2 pal e io, — asi hae teat 2 * e enact Pete ete be 8 an She HAD ‘wails * e ö er thet ee e care it Wp, Tedeud Age de l ee g c nee Cee ek eve wel. „ dosed oe ek * „ e dens thd, poe t enn 10 3 e abi Nag att eee ee wets ee sd? eee ee ee en, tun 8 20 increase in volume would compensate for the losses due to neturel mortality, and the mortality which is caused by injuries sustained during the dredging and planting operations. : Finally our figures may serve as a criterion for comparing the yields from different beds with theoretically possible maximum production. This will enable the oyster growers to appraise critically the relative efficiency of their methods of cultivation. another aspect of our studies that may be of interest to the oystermen engaged in the shucking of oysters is that devoted to the determination of the average total weight, weight of shells and weight of meats of the cysters of different groups the age of which ranged from 5 to & years. The results of the study showed that the average total weight of the oysters at the end of the third growing period was only 73 grams, wheres at the age of seven it was about 216 grams. The average total wer ent of the oysters constituting the age-class designated as 8d years and including specimens between 8 and 13 years of age, was slightly over 280 grams. The average weight of shells for 3 and 7-year-olds was 50 and 167 grans respec- tively. The average weight of meats varied from 10.1 grans for the 3-year-old animals to 22.1 grams for the 77-year-old group. It should be remembered that since the oysters were examined in November, the time of the year when large quantities of glycogen were already accumulated and stored in their bodies, the meats were larger and heavier than at some other period of the annual cycle, for example, soon after the completicn of spewning when the meats are usually very poor. With the increase in age, the weight of meats became proportionelly smaller, whereas the weight of shells gradually increased. In the youngest year-class especially kept for this study and which at the time of examination hed completed their third growing season, the meats constituted 13.7 percent and the shells 67.6 percent of the total weight. In the case of the yeer- class composed of oysters from 8 to 13 years old, the weight cf meats con- stituted only 10.1 percent of the total weight, while the weight of shells rose to 80.3 percent. Examination of the data for the intermediate year- classes showed a general trend toward a decrease in the percentage weight of meats and increase in the percentage weight of shells with advancing age. The data offered here represent the results of observations on the growth of oysters (Q. virginica) of different ages in Mi.ford Harbor and to some extent in Long Island Sound. Since our observetions were con ined to a limited locality only, the conclusions formed cannot be considered as applicable to the oyster populations of all other areas where those animals exist. It is thought nevertheless, that the results of our experiments may be used as a criterion for the growth of oysters of a rather large geosranh- ical district, including the shore waters of the Stete of New York and of Wan oc awh manead ail | is: . e ee a ahbe e 1 OE pony & me pyre Nene rege | a a ‘eae PD ar cunabeert uche “nati a ir phen oo) tote bo kt Re elon ot leo ke bts eee Of eee wee elt eee n eee * bott em e Sit of. een Te sd yen dene e eee ayo tw toogas reo a Fa ed ald oF bygeved taiy af eee to poets ade ok bogeute. | sen to e tp aileds ‘tw. S riper re — * sQetevs, 1 4 een e e dee ü 20 ce add wquoty eb to ts Patou Lescr enge tg ed? feds bomode. ölen ett to e ae ie peasy. TY wow bottec gutwots Piidy eff to Boo edt ta etm Wh Bigses Laced olwgevs ci? .sety OS wWode aaw dt eves e e eAF | Sabin ton! Gig eyo, “8 en Dosumived soplonogy wee Antag e toFeyo 2 4 ere wltcolle caw ,onu . aper th Sas @ sooxted agembpege- W pee Bie OF aaw abloedosy-) bos & to? aifede = Linsey auaweme * Waa 4 * * n det avery £40L gioxt hobtav ug et to be nn aa 3 ad Blows, 12 2 on i gi * aue tol en 1.84 * K 1 _gkaiicd Ates ah pense lly fo pnt ae brow 3 be nee 22 A ARR a ei Fo fokieg ene ame oo odd aetvecd bee e enen teen edt en ee ost nedw e 1% N Te ois ne -neca ee Py N | ib ib any TOOE Ytev ¥ Meno, bed 8 te Aan ul s at ssen og , ene 9 . F titer eit asocedw ~sotieae | e ‘to te ta dokiiw Dae ybuse atit 12% ee ylintoegae eee WAL isenod aisen ots .nomewe adiwoty Sutds aiod? beteb bed N dae odt al te isfox edt to Fate . Lee a 21 N edt ,bfo ae SL ot O wont eee to een aie 400 ai? ech ten 3 att. "to ca A elne bs “i 0 ah ‘edd tot Ste edt ‘to noltoninodt .dheoteg S408. ede off Ai ceeaxedh o brewed Udowt eee o dewnde void — 1⁰ ne n odd a2 eee b 5 5 Laa ü emceltt tz Boers une abn arabrogye ne A -deetzces vaztel Hee Bh 10 ated) de bile Ke wok d G ont % 21 New England. Although it is quite probable that the absolute growth in the different sections of this district mey show certain variations, the relative erowta, vepresenting proportional or percentage gains at each age, would probably closely resemble that observed in our experinents. Ota Grade edt tele „Lende eee eee pode ven he fond te, a „ nas x00 50. Ie terre FM, eh. fl ii i ‘ay i \ 1 ay! i 1 1 . i 1 ¥ M 7 19 } 1 1 if MY . i hy yt f i 2 a 5 4 ; ' i fF a | , i ; SVR Gal ST | Lian i 1 eee be : vm i Vee wl 3 7 1 l Ais) Puan * 94 0 * N née Pe ‘ { t ; ' vi) i 6 Ak { \ KE 1 0 i * Ti . AY wih i LA } 1 I J \ 1 , N 1 SOME OBSERVATIONS ON THE FEEDING OF OYSTERS WITH ESPECIAL REFERENCE TO THE TIDE A. F. Chestnut New Jersey Oyster Research Laboratory Rutgers University Growth and fattening of oysters can be said to depend primarily upon many factors in the environment, all of which have a part in regulating the feeding mechanism (Nelson, Martin, Galtsoff, Hopkins, Berkely and others). The quantity and quality of the food in the surrounding waters produce the desired results after active feeding commences. Feeding has besn shown by Nelson to be closely correleted with tidal cycles, with active feeding taking plece on the flood and ceasing during the ebb tide. Loosanoff and Nomejko, however, concluded recently that under favorable conciticns in Long Island Sound, tidal changes do not affect the rate of feeding. Their results, then, do not Iend support to the theory that oysters are relatively inactive during the ebb tide. Random examinations of oysters in Delaware Bay showed some discrepan- cies when attempts were made to correlate feeding activities of the oyste with tidal cycles. Such variations were found as oysters with full stomach contents during the ebb tide and oysters with empty stomech contents during the flood. The contents of the stomachs were withdrawn with a pivette as described by Nelson then examined with the aid of a microscope. Comperi-- sons of numbers of stomech contents examined by this method showed a decided difference between the oysters dredged during the late flood and those dredged during the late ebb, although to the naked eye some of these samples appeared the same rich brown color. The typical stomach contents of an oyster dredged during the late flood tide consist of a fairly large emount of dark, opaque matter suth as sand grains, plant cells and detritus. The diatoms usually contain chloroplasts and from ell appearances are undigested. The typical stomach conten*s of an oyster dredged during the early ebb tide contain fewer sana grains and evidence that a sorting of material has taken place in a few hours ‘ime. The diatoms ere nearly all digested and the cell contents heve probably gone into solution thus giving the stomach contents their brown color. In studying the problem from a different approach it was found that oysters when kept out of water from two to six days in a cool place upon examination, instead of finding the animals starved as was enticipated, the stomach contents were dark.in color. One such oyster was found with its digestive crypts full of oi]. globules, presumably of diatom origin, which stained readily with Sudan IV. Occasionally an oyster was opened which when cut through the stomach, the contents gushed out freely as some oysters do when opened immediately after dredging. Many of the diatoms in these stomach contents were unchanged end had not been digested. The contents of oysters 22 My a cre hha. Wi ene i n de e 10 ee dre via irene ee ake poe 2) me ee e Ga ec af i i the Baer oviton Whe eee late Wo t, Bedslemren Wee od OF Abdel eee e e ie aw, ee Seow eee ee ee eaten ub dungen ee W e e e een en i wily uty Mb) ; A . „ of iit | ‘ad Sa nats to eee i Giticlucd: ot ca a Sve eee to Lis eee eee elt int Bae nde eee , un ent oi dae odt to goto, big. V Sni § tal . GE mmeote stead and K. seooxacnon A e evitoo „ T dae Wataz tec ne dee I aaa Aue, ü book ent go n n e ee on tect N eee eee eee 1 Pode ie e 2 ‘ade oe te ton of wegaady 4864 bases Selah ga wanes edo aus eaten oecd eh e enn ta . wt et 30 agg kuss . 10 » Bete e ke Sor tiny, Fan een eee e chew even eee doit See Coamura ee dior eee hun One cide ved a ar ae we be e A fen as tte eee eee ee alte “Bp, . e eee eee e e SO bike, e ee dme Be T ie Feels Her ate * Ponta xn güne nnch 8 2 LA * id bh d Ha 860 Stel oft, Ude baybech pratt ee ee usch To en oye bean old pt 4 “tala te Lata e 1 . e sat 2 1 10 f e e ee ee ce oct | i ome. ee 41 mort . d Rae eee ee ee e e abst duo eee e S rent, Be getaye fe enor! ee welt. okt eee corgd ged Ledrodelt to a eee » Jat ‘soaker a ee wrad eee thos ot Dus Boteugkh Lie eee ome ee wae | be un edt ante aug edt eee ee eee ee e Fed Gio? wm ot iy) - pawsottie 8 w meddong adds onthe ak 1 ee we r Looe 6: ; F tee e Ons ee Todaw to two lee we ieee, ann Neben gat as. Wee alantios oct polbutt Yo beaded, Ast atin bat aoe seco eee and wtoloo ob ee Grow etiee Homie e ee stark Io ying ee ce n Eto to Lie aste @ ited de b Nene edn todays th e ee, VL maha cyber it ey “ab enetaro enon 24) flour’) dye) estan, ‘Aine deo edt „nes en * ble ogodd at uc ae e e . weh en Tce h d en to Acc ext Faia 0 We n a ik en eae, actes, {day 23 kept out of water for as long as nine days at air temperatures of from 50° to 60° F. differed only in becoming very viscid. It would not be wise to draw any definite conclusions since these studies are still in their prelim- inary stage but at present it appears that when an oyster which is actively feeding and with full stomach contents, is removed from the water, digestion ceases upon the dissolution of the style. The data from such oysters kept out of water and from actively feeding oysters dredged at all stages of the tide indicate that digestion continues at a fairly rapid rate in oysters which are passing water through their gills. Some of the stations in Delaware Bay and its tributaries used in the routine collections of samples were selected as locations for further studies of feeding activities. At hourly intervals, approximately fifty oysters were dredged and examined through portions of the tidal cycle, with emphasis on the ebb tide. The oysters when opened were separated into one of six groups, based on the color and condition of the style or its absence and a rough estimation of the quantity of stomach contents. Since Nelson has shown that the style is built up when the animal begins active feeding, and Martin stated "that the style is of very considerable value as an indication of feeding, not only on the basis of its presence or ebsence, but also on.. its varying color and consistency” the presence of the style as a criterion of feeding is justified. The results from three different areas sre presented in the following tables (#11, #6A4D, #13). The three columns on the left indicate the nydro- graphical conditions. In the right hand column, the dark brown firm style and full stomach contents indicate active feeding. The pale brown fim style and presence of food are interpreted as the beginning of feeding during the flood or the first signs of cessation of feeding at the first of the ebb. The pale brown soft style is a further indication of cessation of fecding on the ebb and probably the first sign of active feeding during the flood, (see table #11, 4 hours flood). Some overlapping may occur between the pale brown styles for some cases are not clear cut. The white style and the ab- sence of styles are interpreted as complete cessation of feeding an hour or more previous. Station #11 is at the mouth of Maurice River, an area where oysters rarely grow to market size because of the prevailing low salinities. The oysters are typical low salinity oysters characterized by their thin, white shells and stunted growth. These oysters ere tonged and sold for seed. The results at this station show that active feeding ceases et low water, with the greatest percentage of oysters with no styles end no food occuring soon after low water. Salinity is, no doubt, the factor influencing feeding in this area. Station #6AD is located in the third reach of Dennis Creek, en area re- served for the tonging of market oysters. Large, well-shaped oysters are found here usually in a good condition and sold by the tongers to the g ak 50 gel N Astro an nm ‘esi lio tet i oot ay on PRR LY nee ype» 20225 ee rr 1 } ken a Rt ak Arte Wie eee ee conto eee Sete Ee * ; Klette ei ee te mode tote age tf tanner ta ted enete er, boughs eee pid mock overs: vt .acuataos doeh de LLY ain Bas Sale os, to bs mont eee oAT velgte odd Bo coteubowets edt be debe an ec | tg. td Boulos arate aothowh Wer tede i one te hi’ N . bid yitist s e Gen tn goes tad? ‘ste b f a Lt eg laben r sored oe: i "i oe 1 0 nnn acht hae takt 0 u enoltede end de 6 1 Fare fot ano dg aa Datoatus a asignee to Ace gk ep „ a en I yore et anaes ener rats} th | .daftiviton ag if q pe eee tty ee Coheed odd Te eee duvet hombinge fre | ee , exotayo wat Bas 1 Wen s bio See att e ciyta ale Qo eee ting, eee anh ‘HO 4 . bee corks aa NORMA oante, ed mee Yo eee ben Yo 1 % a ae ee bite ee eee eviton ac ee en ois ee qu aga al ee one de eben cited ao ovlov. oldamentaune de to ct eee ont le Hews ene Cale SUE) eee 4o eonceeny e To etead eit no qino tou Dtbs rte # * 9 aut to een e een, dale 10% en 1 fiat reat et Bak web WO | Ente wit 1 e ate ü ann youd? pet Ee i > | etary ade hel oat mo vibes wert of? 4 {ech ton € rth) ast e a ue ty T . aid eee Sted er edt al eee een q h erceduss domnete Aiek Baa - te sutveot ‘to n akg edt eg be ee wt fool I epmsacts ae Shere | Odo ode to nett ot ge yotbos? %o woltesnss To e Mex) oud ao Hom ene 7 n o ak aixdh Woe ayo oeeg er | n ety ylosdesy En aap wae Be D nakedelrevo ome - ~(bo6Lt gamed if \ LOR oy ae oe) wie Oe Mote obits, shad oll! ‘two eee son ete See smoa 10% 4% mwoxd . 7 ern es Wiitbowd to aaa ieee A bevotgredns ate etivig To vores || nut Gn 0 i] ( 1 N 5 a0 otesty nens n „ en ect YO wee e th at LO) een ont enen wos Anh keveniy avs to oadaoud ote toxtram o¢ wory WI etka mit ae yer bas edo nüt eee wWinkisea e eee exe eee ott ben tot doe tte bagact aim ee seed? eee eee tap eee Are eee wel tis eee pobheut atten You? woe nolreta ahd de ehe Hoge Ale hoot om hia u cd pol hte eee de ogsdrenieg Ao gen oat RE dert bos nee N 5 e on Be tete ee wed i 1 g „eg, q e dene mg luda banat 20 dott 1255 ‘eee oh bovaool at ane eb q "Orin eee en eee ysis | “ole Scene Lo e ene tek bene | gat Gt) e pat e itis vis N abe bee e ih Wem, an n 1 shucking houses. In this area we also find that as low water is approached there is a uniform response to the decrease in salinity with the complete cessation of feeding activities. Station #13 is in the privately leased area of Delawere Bay, located offshore in one of the best growing and fettening regions. In this table the discrepancies mentioned at the beginning become evident when large num- bers of oysters are opened in a series rabher than rendom samplings. Here the saiinity and tempereture hee changed very little yet a decided differ- ence is noted between the percentage of oysters feeding at high water and those feeding during the ebb tide. In view of the light that Nelson's work was carried on in a tidal creek where the salinities approach the minimum for oysters, the results in the first two tables (#11 and #5AD) are in accord and support his findings as well as his conclusions, mat in New Jersey oysters are relatively inactive during the ebb tide. Studies have not been made in the higher salinity ranges but on the basis of the findings at station #13 more diverse results would be expected. It is possible, therefore, that the difference between the findings of Nelson in New Jersey and those of Loosanoff and Nomejko in Long Island may be due to the difference in salinity of the two areas. Nelson's observations were in waters of optimum salinity and below, whereas in Long Island the salinity is at the optimum and above. I fer See eee tay 45 Lest a e dots t3 at 25 TABLE 11 PERCENTAGE OF OYSTERS WITH FOOD AND STYLES THROUGH A PORTION OF A TIDAL CYCLE MOUTH OF MAURICE RIVER, MAY 8, 1946 ; Pale Br. ; Temp. Sal. „ No Style No Style White Soft Style srt Style Pale Br. Firm park Firm Style o. ppn. Tide No Food Food Present Little or Little or Style Full Stomach No Food Food Present a No Food 13.9 12.1 43 ebb 75 0 1% 17% 3b 35% Wie 10. Soebb 35% 0 N 15% 25% 43% 12% lig Yel Las 20% 0 10% 50% 20% 0 ee ee ee wre 0 1% 42% 5% 0 lie? lee, i aey 8% 0 0 5¹¹ 28% Wo ieee te tid 16% 0 0 10% 34% 10% en den ee TR Tse 3 — „ 2 oe rs fos. Yop 376 35°F saad * — 8 “ones, oe eee sive ees Oe Oh OXBLISEZ * WO CATES eee * ren 0% y aber CACTE - re FF TABLE 6AD PERCENTAGE OF OYSTERS WITH FOOD AND STYLES THROUGH THE EBB TIDE THIRD REACH, DENNIS CREEK, MAY 13, 1946 u ee Pale Br. : Tide No Style No Style eee eS Sia onan) Be Harm Dark Firm Style No Food Food Present ieee or 0 5 Full Stomach No Food Food Present No Food 15 ebb 15 0 0 0 105 86% 24 ebb 26 24 2% 0 3% 60% 3z ebb % 0 2% 16% 50% 30% 1 ebb 2% 0 6% Ali 4675 2% 53 ebb % 15 12% 66% 14% 0 Dell. 24% 22% 18% 32% LS 0 I le 38% 62% 0 0 0 0 it er 1 un kee aes 0 D 5 9 * — je’s r Jo opp 2 * it f A re bend .- > . : 2 a 8 Weg 1 23 eG tin _,. Aenea ag een eee Iaer Je on SPE SE parr eee . STR? ay Sere yo Zeh ye 8 le gens 3 Dr Line e 8 291 1 alen Ae ayaa 4 eae ee K Line SS Ges Ole Ache oe BOTS. ee Eee CH’ DIE e WE gar ane: Ok GOf20882 Lid MOGD Vid SARTS2 CHRGRG ZHE EDS Cine 27 TABLE 13 PERCENTAGE OF OYSTERS WITH FOOD AND STYLE THROUGH A PORTION OF A TIDAL CYCLE EGG ISLAND BAR BUOY, MAY 16, 1946 oS SS SS SE eee White Soft Style Pale Br. Pale Br. Firm e e eee ee MM gee ee ir No Food loser 26,0 5 fd 14% LZ, 2% 0 2L% 56% 16.6 18.1 54 fld 10% LG 8% Ld 154 5855 Uno ee “Hews 13% 0 0 2% 18% 67% 16.6 18,0 2 ebb 17% 0 10% 2 19% 52% 17.1 17.1 3% ebb 8% 3% 855 14% 33% 33% W763 16,9- e 1 6% 8% IES 32% 36% 17.8 16.8 uu ebb 10% 0 16% 16% 42% 26% 18.0 17.0 5 ebb 0 0 14% 16% 7 36% JJ ee ee ee og a ee aS Se A BRIEF CRITICAL. SURVEY OF THE EVIDENCE FOR THE HORIZONTAL MOVEMENTS OF OYSTER LARVAE Melbourne R. Carriker Department of Zoology Rutgers University Over the years evidence has accumulated indicating that the larvae of the eastern American oyster display certain horizontal movements, inde- pendent of, but aided by, the flow and ebb of the tides. This pacnomenon was first mentioned by Dr. Julius Nelson in 1911 and in 1913. In recent years Dr. Thurlow Nelson has investigated this behavior in more detail, and describes their movements as follows: oyster larvae are herded horizontally into swarms of uneven distribution. These occur in definite lanes up and down stream from spawning oysters and are so distributed by the tidal cur- rents. Heaviest sets occur in these lanes. Larvae do not seem to be dis- tributed laterally to the current to any extent. They may move upstream during the later larval stages, further than can be accounted for by passive tidal conveyance, by remaining in the fastest curreats on the flood and sink- ing on the ebb. Larvee are thought to be stimulated to rise on the flood by the saltier flood water and by the increased current velocity. They tend to remain in the strata of greatest salinity change (the halicline) if such be present. «As the tide increases in velocity, the effect of current is added to that of salinity, giving the larvee a maximum stimulation to rise. it high slack water they tend to sink bottomward. During the ebb only the current stimulus is received. 4 decrease in salinity, caused by the inflow of fresh water, depresses larval activity, so that the total stimulation is thus probably less than on the flood. In a recent criticism of the Nelsons' theory, Korringa, a Dutch oyster scientist, points out that the congregation of larvae in special strata of differing current velocities may result in horizontal distribution, but doubts that this influence is as efficacious as assumed by Nelson; for al- though the influence of salinity makes a movement upstream possible in prin- ciple, the combination of the influence of haliclines and different current velocities may well have a resultant in another or even in an opposite direction. Korringa, however, presents no evidence to support his objection. In the Oosterschelde where he has made his observations there are strong tidal currents and very little salinity stratification, so that probably he was not in a position to notice such effects. He states that the European oyster larvae are uniformly distributed in the Oosterschelde, are moved pas- sively by the tides, and their distribution does not seem to be intinenced by temperature, currents, salinity or light. Yet in a subsequent pausage he writes that he has often met with peaks of greater or lesser larval con- centration and with differences between the number of larvae at she surface and at the bottom. He thinks these differences are caused by the proximity of spawning oysters. He took only e surface and a bottom sanple at each place, and thus did not receive a complete vertical picture. und finally the European oyster is a different species, so comparisons may not always agrece 28 ben ar 1. ee | RV tene We enen Der nie Bes i) e ee | Te A Feta to ogee: aie 1 ae 1 M enen We f oe 0 oes tet g mla! . sod, . n n Hd q eee Letaogteot abormed tigeth ee impair em: ated U, n 160 uc br ee e ho ce ee e Oe ge hates e ee, toma e en He LOL at ge Aer ak mown ee yal ye bar gv Ka d ee prea dt wude e ric EU Mee Ged poste ent Kü opt dae eren Dot ote eee eee eee oy eee ee eee dee ln de eee eb at eee ssed? ee eee l, maven Ro ere e 0 7 e Yet eee be eta haw eee a ear aux E Mö e, pores 50 of dee ton Of Wewtad vaenel ened Mt thea) whee. be een Mihai) ny aerate evita: Yom ge! eee aun iat note. eid ust eee „ Wen Ye de ba e at den dee eee lee Sorted Wet ie pent e Gas Bods wd ac etry dnotee’s, edt at ee e eee oe: e ee de eee ot Hire te od e eee etm bee bee e uD, ee e, e ce eee ee ee eae e Bete “cotton ene Ae ee e i bels, Ne es fou ce), cee ee Wie ener) Fo. dee dae and Ee os 7 aan au Peres te Fo e ond -aphtooton mi eee Obit edt ie, „eee 0 et OF Modyatuns v0 Sanuk cant 8 corte elt nails „We b te to coud of Belle An ise ee ee eee sorewadiyod sata of bad yodd Tce Me ole f 100 Wok kat, et hegueo eee at eee 4 sbethooes et ee eee aS | ma fe Latot odd tous oe nee levied Gn ee rete 1 4 . f eld ent de walt eset Wande e ö Ni ber done „ ec ,yroodd ‘aacedet emt 10 UD re tases 8 a | Hida etary fatooqe nt caveat Yo sotteyetgoce amt tadt 240 eg eltne ten dee ede eee eee i ee ya e eee ee f An 40% nee bott yo Nene oo ee ee e aa e eee a N ace aa at @ c et e, eee ee 3 axon Wee to epkenttat ott | MOREL Hi een tc Get b ed? ko aoktantdmes a atta A Oe e KA Me nee e A cds at Inetiteey e aved thew e wabatcoke a ee e dangque , ,REETION ako MOPTR | r od dnote whiedoemerath eae ain) Oo eee tw OM eee twats: yiicilee eftthl ee bie aimee Lemke } Ag w ode Get ete OH! eee dove colton of e e e BE: Om en, et fy ee em eee ait ob ben wle tr h yr os exe ee . d De od od eed Ree wer m c det ok Bene ah eu oye 1 Weener rot ae Ne n e e "yo 40 Vn Lan hod seeker een e h NR eee re e een oe A dor ade, oath eal dol eee gel wart ed? de eared: Ney omit Meh eee ennie n Abu bat eee ysiadno edt vk Hold, Sun dee h ade watt a eg 0 ace din Be Ae I eee e e , ch e kene M ne ee n ee ee bad idle 7⁰ 4 ee a ea aN Ke eee, 0 be e (Dk. ee e e e dot we e sil at seminal 0 Ce en W 29 A brief review of the larval period (taken from the researches of W. Brooks, J. Nelson and T. Nelson) will make clearer the evidence for the native movements of oyster larvae. It is thought that sexually mature oysters spawn during the late flood tide, the total annual production by one female being estimated at three hundred million eggs! Sperm and eggs are thrown into the lower strata of the water, where fertilization occurs. Early embryos do not develop swimming organs (cilia) for 4 or 5 hours, and settle to the bottom at the rate of about one inch in 7 minutes. However, in a current of 0.3 mile per hour or more, they may be carried some distances ifter the cilia form, the embryos crowd to the surface, pursuing an active spiral progression through the weter. About a day after fertilization, the embryos, now larvae with complete purse--shaped shells, are recognized as straight-hinged larvae; they measure approximately 0.06 mm., and sink to various depths swimming actively in all directions. In succession tnese free-swimming larvae go through the stages of “early umbo“, “late umo", "mature®, and "eyed". Eyed larvae are relatively more powerful swimmers than younger larvee, and although they are unable to meks much headway against a current, may rise in less than an hour Yrom the bottom to the surface of shallow oyster bays. Eyed larvae measure about O. mi. After careful selection of the proper attachment site, in or during relatively still water, they cement themselves to surfaces on the bottom, and are then called spat. In laboratory experiments, T. Nelson found that older larvae became more active when a higher salinity was introduced, and less active when less saline water was added. Currents passing over the larvae stim- lated them to rise. In still water they came to rest umbo-cownward on the bottom in one to 20 minutes at summer temperatures. The Nelsons advance the following points in support of their theory on the movenients of oyster larvae: (1) Most larvae were found on the flood tide in estuaries of strong tidal currents (Little Egg Harbor) end in about equal numbers on the flood and ebb in those of less currents (Barnegat Bay) They do not state whether this decrease in the number of larvee on the ebb in certain bays is not due in part to destruction of larvae by enemies. (2) Distinct variations in the number of larvae occurred at different depths on the ebb end on the flow respectively; the youngest larvae showed no marked differences in vertical distribution, but the older larvae steyed in the lower strata or on the bottom on the ebb, and in the upper strate on the flood. Stauber, in a singuler instance, once pumped 700 eyed larvae per 100 liters of water from close to the bottom at low slack weter in Delaware Bey. (3) In the horizontal plane they found the earlier larval stages farther down- stream, and the older larvae most numerous upbay. (4) Setting occurs far upstream from spewners, farther than would be accounted for by passive trans- port on tidal currents alone. Also, lervae suddenly return to set on beds over which previously no younger larvae were found, as in Long Island Sound. T. Nelson, however, gives no actual figures to indicate how far larvee might be moved passively by the tides. (5) And finally, since in local ectuaries the tide usually runs for a longer time on the ebb than on the flood, there is produced in combination with the current caused by fresh water coming down i Nn ott al 9 . Areal, 5 n te ebe die dc e dem AE cee sl neh Tae rc wette a e ee 106 b an ME eee Louie Uptot odd: eee boot? d e eee ae eee, ee Sop wig? ee e ee e beer te emen Sin dec cee serie’) RO, tant eee ee odd ‘to eee ee pity otek awed ene | Bia vated 2 so} sot (abit) auegto satuatme adores be ab noerdne wheat | eNO, eee Nol Wom eno tomdy to ett ene fe ae ant oF eee ae % Ecke Htg eel lem Kote dere yo teal oc ee ce ‘ho dewey wah] ROD ae gett were eee ee ade mit twee Ge en e, sano ee ott een RE vetted es bigot provi Hie dyad eee on demote we e ee ha | ite dbetexnooet ap ee Nec ene e esse Mee mained we 3 1 we Anke Lue tet eee eee tunen Yedt ee ee. Phat eee of ee eee ive sb eee ee e 7 enen e eee ec Mee een weld dee ni wie wait 22 Mentee, aeg f e e et gid eee ee eee 0 eee ooo OM eee, eva ae kee ee deen eee at Od mano? els nol") MMO ma modi ome amb emit bee he een ee eee mee ee eee Mt Wa ey” iver Ln 1 ed den ba woh at „eite tte cn rope ond to b S, bre ar, Fal cy et ee ot) ele Kah a e beth bombed Haage W e ere e Wreasodat ot n seen pica 00 neve gis Hees “f iB nv og au ros e ann aon rener adie Yew? of otto Volt how Gia nD e et ee mane ‘eer ener Ent Gab: Sm OS og saab Wa bet e 10 cdl uf te senen ade h ug eer) a id 1 edd nd een ee eee yor CL) eee ene e 8 fs i og yee e eee eee een to s h%,t we eee Genk Io axons bt dhe tre eee ade pe uns enya td a vasetbob wine lee emake Shim pnt eee oF tag ib ooh gon gh aged OTe ane 40 ohn At at ef r i 10 ont ob ee damn) ee ox be sects a xe bee c „ l $B, ite. e ae ee bar NOR e een eee eee etn e e 9 0 tat brent t bl 25 eae nt) ett swb nny 1000 Ane NR b en av Late tot; ehe Nek ge b, eee e ee eee e tot eee aM. Bie 1 cle ee n gem, o werten, ee e ee Macc eee e e ie e ee Gee, e eee met wort nta een ee o: La ede BORD iy Ge e Jwoolk ane) Se yay 2 Oth 15 „eh en gid Ys eee eee e ren bon lie suid uid og ge on ai ae Boe 4 el mod wine . 30 from the streams above, a general tidal drift which tends to carry all freely moving objects oceanward. The fact that some larvae, even though carried into the ocean on the ebb, return to set in the bays, would indicate some independent movement exerted by them. The Nelsons do not indicate however, out of the billions of potential spat in larval swarms, the possibility that great numbers of larvae may be lost et sea during normal weevher conditions, and still leave enough larvae for the usual sets occurring in oyster regions. An analvsis of such factors as salinity, current, temperatire, light, turbidity and pH in larvae-bearing waters has been attempted by various investigators in order to determine the fundamental biciogical principles which govein larval behavior. T. Nelson in an extensive study of the effect of salmity, principeily in Barnegat Bay, finds that reiatively greater ag- gregations of larvee occur in the halicline. When no halicline is present the larvae are found in greatest numbezs on or near the bottom. Korringa writes that according to Neison's data the larvae in many instances remain uniformly distributed in the absence of a halicline, A review of Nelson's data does indicate this. Perkins, also working in Barnegat Bay, came to the conclusion that salinity is not as important in determining vertical distribution as T. Nelson believes; and Korringa, after a review of the work of both of these investigators, concludes that salinity plays a greater part than Perkins is inclined to admit. T. Nelson reports that the records of seven years show significant numbers of larvae only at the halicline in Barnegat Bay, end that if such stratification were permanent few if any larvae would set in the deeper parts of the bay, but would be swept on the flats where no significant salinity gradients are evident. This has been shown to occur. Salinity gradients may, in part, explain larval movements in bays of slight tidal currents such as those of Barnegat Bay, but would not seem to play as important a role in estuaries of strong tidal currents. Perkins, after a study of the effect of current on the vertical dis- tribution of oyster larvae in Barnegat Bay, concluded that in strong cur- rents larvae are distributed vertically according to the water currents, that when current velocities are low and salinity gradients relatively great, lervae congregate above the halicline, and that if the current is negligible and there is no halicline, the larvae are found near the bottom. Korringa in an analysis of this work, showed conclusively, however, that in some of Perkins! data a relatively strong current has no effect in con- centrating larvae in a stratum when a halicline is present and that in other instances a relatively weaker current, which according to Perkins should play a part in concentrating the larvae, eveniin the absence of 2 halicline does not do soe Forringe further believes that water currents are not great enough to bring about the effect observed by Perkins. In the strong tidal currents of the Oosterscheide Korringa says he noted no correlation between current velocity and larval distribution and yet his data show instances where more larvee occur in the surface samples than in the lower samples, And further, he collected his greatest number of larvae (2,000 per 50 1.) at half flood in a surfece sample! A serious objection to Perkins! larval work, as well as to much of that of others, Wett 1e wurgb cc Motte d dank — „ ec rn de Ku ene e eee eee en told eee eae eee gere auen e ee ett edd of ton ot — e sit no ngen ord CBM Lit ton ob anoeled on. «madd ye cee tietkegg iat Hitec, si? eee ee ot „ to oe edt tu- dem, Ne e Lenmar: pase poe Gas ag | Pavan) bo: dne N eve a mud ate Leman ett not 0 tig νẽ at iste One „ 6 M a 6 een dee mum bete ep probeek dies 1 atevlane an 7 4 ei, r anbepethemeael ci ig bits „ ae ze TH ge eee ait t Sr h e ee nd att boese dae de Wien een e at enen .f t vnd d Arn h eee erte et Bhatt yet aden * Wang ang en Bt ethiviies on agu sedtionied dat, aut Tong S Te n stotted oft tage to AD ee ee dante = bout eng beet ya at eee ont ete ono Mor ga. a0 watts A ent tea 6 te oon ge vi al E 09d eg hl 0 state of ‘Seathont at e ft gate len ect de Vo We to eroduut tasobihugte wode yng Tk Wet eee otew aOiteoltiterts dowe ML tadt bea yet gages eet oo ee ed Olver tid (Yad oft to arne teqeeh sit at „ b mood dod aif? .tnebive ors etnelbats W Ae nb Atagte on ei rif aner vom fevtef tate tiny mk vom etootbaty Ytinilee 426990 OF BROS | Blpew gud ,ys6 #agente to cae? ae dom etaexiwo ishtt saute To eyae ae ed i febtt ae to soltautes at efor s aero Be woke ot . on 2015 tertsage itt be nente Yo Sage ‘out to bn 8 0 ate 4 aid gutta Re fae Seton wel Fopsansd ak ode nth ceri | beer weden add of dates kate ner bedud ete 9 ots oe — e , taewws cede Rage et e e BAF TE Hott inp ,entlotled eit evade ot mee aif Rhea Hest ste oevinl ott eat folgen o¢ phe E told ee ee e bebe Aich od te pi nai na ot pig | +100 bi Joetto te gal toutes gausts ylovitatert 9: aah eahited to. hi Tau ban hes en ef tler ten e e een gt eee f an e of ee ee eee eee en e een ee apo. 7 r r bYrerive r ted? ⁰α⁰αð.e Dun mme t ren N gon ag 3 a etre yo Sovtes d Poethy ee ee oa ae or ee rig tom aay on Baton otf eyse eucltied ebfedeatersed old To nere Leh „ene tn toy be nobtwiixtalh Tce Bae de cler genie Ab solids ; gad ds dnss sontaye edt af 4990 eavand stot Soc bain we to Acne tec gen eft betoaltog ed Yast dn el gene e ö 4 eee eee e me * thot tu 1% 02 Leg G 82 dne 10 fade 10 oun oF a ee n ene aue rok 31 is that consecutive vertical series of samplings have not been collected throughout the cycle of the tide. As to the influence of light on larval distribution, Korringa, along with other European workers, found no correlation. T. Nelson finds that in the presence of light, eyed larvae continue to move until they come into shede. J. Nelson thought that larvae tend to stay near the bottom at night and to rise during the day. The effect of temperature on larval movements also deserves greater study. Korringa, though noting no correlation between temperature and dis- tribution in the field, thinks that vertical distribution of lervae is not the same at lower temperatures as at higher temperatures. J. Nelson believed that higher Vater temperatures caused larvae to rise to the surface. He counted more learvee on warmer then on colder days, end observed that in the laboratory embryos swim in schools in ascending and descending columns. European workers observing the same movements in the European oyster larvae, think they resemble convection stream movements. Perkins found no obvious correlation between pH and larval distribution in his Barnegat studies. Such factors as the effect of food and of turbidi- ties on larval distribution heve received but scant attention, and merit further investigation. In the summers of 1938, 1939 and 1940, I studied the vertical distri- bution of larvae in Barnegat and in Great Bay, N. J. Series of successive vertical samplings were taken through the cycle of the tides, with salinity, temperature and tvrbidity observations. Unfortunately, current velocities were not determined. Most obvious result in this study was the extreme variation in both the horizontal and in the vertical distribution of the lervee. Roughly speaking more larvae were found in the flood than in the ebb in both Barnegat and Great Bay. In general, a tendency was noted for the younger larvae to remain more uniformly distributed vertically then the older ones. Strata of meximum concentration of younger larvae jumped over the vertical picture somewhat, but tended to rise in the early flood, to sink around high water and to rise again during the middle of the ebb. Older larvae were never found in sufficient munbers to obtain a clear picture of their movements. Eyed larvae, however, showed definite tenden- Cies: out of some 620,100 liter samplings made in the three summers (about half on the ebb and helf on the flood) a total of 82 eyed larvee were found in 15 flood samplings, and only 16 larvae in 5 ebb sanplings. In Bernegat Bay no eyed lervae were ever found in the water on the ee (10 samples were taken off the bottom). It is realized that these are st l numbers of larvae, but then this stage is never as ebundant as the earlier stages, mortelity apperently proceeding at a high rate during the pelagic existence. No influence of temperature, light and turbicity on larval cistribution was observed. In some instances in Barnegat heliclines eppearsa to infiuence distribution, at others not toe In summary, it is possisle, at least, to agree with previous workers that the larvae, especially the older stages, pe eget det ga 1 a 4 ee S der Le e saodtaletyer on bmp een enon en Lee arom ot 1 ovis en n eden aer 90 ataacovest invent, 4 ia Ban an aten houwted sortaloros of% ; don at sen 20 gokmedittuks eee 9 ai ‘frome! Lon conte 5% eee reigtd: te | eee ear 08: . 10 vun of ee eee ne payed | ws ; aten Aab e bute 9 2 ets Sa n — neagerys add xt — eee veat — Tragt tmp it neawted dotdakertes 80e rd on sas apne 4 bg , Gee | n oad ene Fuba. tod Wa va aos e rar flO owns “spe Lote tt eg, a. et Wo Sache eld i ha eee to solkos «6 » Fee ai Sua Sogartadl ob eavrel to motes’ e e ee obit edt to . eee mee e den eme Tae, , wxutezeqmed | . erde edt acy ybide edd ak cinen su tre teh gon opew ‘edd to anttudleroth Leoteray off hi hue Lotuosttod ade gtod at aokvariay | = pt 21 doc ott at bunt orten net enous 8 2 yr 1 ap 5 whi iret ad? SE nbans eels oF Ans. Saree ar 6 17 7 OF d es ot te af bee tevsa exow de ene e fownds ytevoxot eee een, eee stent Qo or 5 ane wit nt oben ae eee e OOF e ee ve sim Baue d crow egret boys BE to Datos „ (bac ede no tet bio dO odf e rte wh ee eee We bak esvrel ef ylio dae ae Lome dankt tun ae Lc oo) wie e e ee e at ee ave ecaw eee Yo atte tins L. e ee ree Made Soni toot of 41 een eit Iie y 7 tind? 3 to! fre ay ee 1 a9 avons ot wate LN Ad ya, 1 8 one een ody a e e * he 8 arden 8 will Wen day ee eee ent ao ace hae tans. ee eee 0 apd Ula 858 ae ce eke eben Meine a eee oF ent th eee e ak ah Oh vat foe ee oovtad odd sous ones — 37 5 1 ee ran “wale wtatouyeo 60 32 appear to rise on the flood end sink on the ebb tide. However, much more exhaustive work must be done both in the laboratory and in the field before this ecological problem is solved. Hypothetically it may help in a study of this kind to consider that differences in larval behavior ere being dealt with which have arisen through natural selection over the centuries in the response of oysters in their adjustuent to the varying conditions in the different estuaries. For, it is doubtful that much, if any, intermixing has occurred in recent times between the latvae of the various geographically distinct estuaries. Thus, rather than an identical reaction of oyster larvae from different regions to the various combinations of the environmental influences there, it should be expected thet a few fundamental biological responses underlie this behavior, and that the identity of these responses is confused in each instance by the interplay of the changing proportions of the local influences. “ mung i | en eat fies hoa Asai at, 0 Bat Cys ba a bt i ; ei Si 0 e ; i ; i thea 1 0 Hl i i VG LOUISIANA'S OYSTER MANAGEMENT PROGRAM James N. McConnell Director, Oyster Division Mr. Chairman, Ladies and Gentlemen of the 1946 annual joint oyster convention: Since the oyster interests of Louisiana have only recently become asso- ciated with your efficient and most important organization, we felt thet it might be appropriate at this time to endeavor to acquaint you with our pro- gram of oyster management in Louisiana. By legislative act, the State of Louisiana has declared, and I quote from the act: "That all beds and bottoms of rivers, streams, bayous, lagoons, lakes, bays, sounds, and inlets bordering on or connecting with the Gulf of Mexico, within the ter- ritorial jurisdiction of the State of Louisiane, in- cluding all oysters and other shell fish and parts thereof, grown thereon, either naturally or cultivated, and all oysters in the shells after the same shall have been caught or taken therefrom shall be, continue and remain the property of the State of Louisiana, until the title thereto shall be divested in the manner end form herein euthorized; and shall be under the exclu- sive control of the Department of Wildlife and Fisher- ies of the State of Louisiana until the right of pri- vate ownership shall west therein, as herein provided." On numerous occasions during the twenty years that I have personally directed our Oyster Division, attempts have been made by unscrupulous in- dividuals to exploit improperly the vast oyster production possibilities of our State. This type of promotion has never been allowed in Louisiana. We welcome, however, and will assist in every way possible, any legitimate oyster interests that might care to avail themselves of opportunities for oyster cultivation and production which our State affords. We in Louisiana firmly believe that at present less than ten per cent of our oyster pro- ducing area is being utilized. This opinion is concurred in by several oyster experts from other sections of the country, after surveys made of oyster producing territory in this area. It has always been felt that it is necessary to lease State-owned water bottoms to private individuals in order that the State may give proper protection and encourege individual cultivation of oyster areas. The State of Mississippi, by contrast, does not allow private leasing of water bottoms for oyster cultivation, and I believe that our other sister state, Texas, has only in recent years allowed the leasing of its water bot- toms for oyster purposes and this only under limiting conditions. 55 175 Lill ta | HMA ACCOR e e bee i 10 ‘ eee me, mne — en des sented ede a. e et hao ered 0d) pa \ Re wad? Slot ow \nobtertragiio 4 1 ie Olle sey n nοαν, wit to ents af toe eames — aheat ot se . : 1 Me e i 1 e 1 0 ae Arete a end rien 1 hela 0 1 N ro. 10 ont d Se bene 70 dbo ti a Ro nortothetaut e * c ine 6 Bun GV L e e ; i eg Lan 46 fl sth e vbetevitlo ro whitened) eee reg Ree San Linde oma ihe apie eee oxy oat 20 ee ay ; ook, sei ea —— 445 e fins bes radade utored art: N ‘% tists ds aeg e eee to orate edt te e, ibe on ba el Peow s qidatoume: 1 l bedogueg avew K nets resp spe: e garish snolesage — no.” jst stiolegerodign ys t . noleivil tageyo une Bow, ede Lidoaseg yoktanhos pale Agon n of ef MALE tol en bewolla Aa 80 8 ) RRM Qed ys of ve * tek eee to e e dt ast 2k e be e vtute e a eng dee tuo. to. to) de Het Rew e tocnexg te taut vetted are Jocoves yd ul byxivoneo 6h eee Bee? .bos!ilty gated @f sete patemm | 20 nen, Rotts eee e e eden ee et eee ene 5 We ai yrovertad eee area J 21 — ler need csg wed dh 3 pivioci dete en ee sae | bemorotudis inst oh reg ven ; 38 ovin Nan gene de e e Be nter ere d a e e ed udev to don ane | ah ud ed Le a8 10 60808 r tetate Nate ron Wee et ef . ere do dc mek amortod reh to ; ated en ett ‘ko e oat pit Anbot ut low med” eam. » a sumo thi tuo: e ee ite 2? bos eos heii an en ive 34 Because of the several hundreds of thousands of acres of natural oyster reefs now producing large quantities of natural growth oysters, Louisiana allows the leasing of these natural reef bottoms, only limiting the cunt available to each individual or packer. Any individual or company desiring to obtein leased bottoms from us would proceed as follows: Locate the area desired, make an application for same to be surveyed and amount of acreage determined. Upon completion of this survey, and map of location having been made, a rental notice in the amount of one dollar per acre per yeer is meiled to the applicant. Upon receipt of this money, a map and leese is given the applicant. The lease is for a period of fifteen years with the privilege of renewal for an edditional ten years, providing that the ennual rental be paid in edvance each yeer. The lessee may then take oysters from his leased grounds at any time of the year and by any method that he finds advantageous. He must, however, obtain an annual license for his boats handling oysters, et the rate of fifty cents per ton carrying capacity. A privilege tax of two and a helf cents per barrel is levied on all oysters removed from leesed grounds and three cents per barrel on all oysters taken from the natural reefs of the State. A fifty-dollear annual license per boet is required for all dredge boats operating on public reefs. Louisiane hes at present approximately twenty thousend acres under lease in small trects of from one to twenty acres. However, a few larger tracts from fifty to five hundred acres are recorded. It has been the policy of our Department for many years to require 211 packers and canners opereting upon the neturel reefs of the State to return as “cultch”® ten per cent of the oyster shells taken from the reefs. In other words, anyone removing ten thousand bushels of oysters is required to return one thousand bushels of shells. The entire operation is done at the expense of the person removing the shells, and the shells must be rebedded under the direction of the Department of Wildlife and Fisheries at the time and place and in the manner prescribed by said Department. Shells planted under this program alone heve been annually ranging from a top of two hundred and fifty thousand bushels to 4 minimum of seventy thousend bushels, dependent upon the annual production from natural reefs. The legislature in 1944 passed an act appropriating “any and all funds collected by the Department of Wildlife and Fisheries for the sales or grants of the right or privilege to take shell or shell deposits from the shell deposits of the State to be dedicated to the establishment of ‘oyster seed grounds,’ and to the plant ing, propagation, cultivation, policing, preserva- tion and distribution of oysters on and from said grounds.” 1 i} U ny * l i 4 J That i N ya MY He lie, » 689 5 , 7 12 ; 0 Nee ‘ RAY i Ni wn 7 6 Sh) aye Hi ae ‘ 10 ö Wh * f " ö ( f 0 nt ni 1 a Whe coe iron af. * 0 a { i We < 1 1 3 U setae 188 40 Sede to. et Se: ae Tete e e ee eee, Ae ee eee eee en Ye ene nee e ies ene e nen, Yams eae eee ee ee ee e eee e ade e ee i Wings uc Tv yk eee e Ae n nose OF ate, rege us boo ‘Boon au worst ac bee 0 00 * ed of Stieg 1 akne hewybt i ‘et 2 ort Lene Both ent stabot . . ie vert e $9 eee e Bets e b eee e wee 4 Tanto Att. ‘Lo Kaen alt, t te Latter s choc coed pabved qoLteook 10 ee ater 18 Wee nen ae e e e ae Gib e dik abs reg he Scene en e e e e ox: Surg ‘Bk: not Sita det * eee e Ged Töne l Mobs ah galt Rowsn ! 7 1 bee ae e en os N Levine at Ae Naito Wh ie Gini eit Cone e ote mat} it pom: ot „ eee e BE Serosa eng GOT ed hoc b e te Bo Bits ei et te chant sald * Aae e eee cid vot eee eee e N * vant „ ebenes wü Om? en en, . 115 bs > ea hartge ee 10 vr Pb bar owt Yo saw el Kad K eee lie de e Uwe e eee eee aoa eee is Bie est Yo siget Daten oly, Lani ie dent 18. eee * d eel ebay ars latins stl ‘ Rune soning txvaanG ae med sate e 4 Aang wos 1 eee . jailt We OF cud ELD Bor ate vated . rik be : are Sb werb e en ot 808 ot 10 alee J 5 uh . noww mae ‘tomtng Ste 20 Salle 4 a Sig. nest 3 Ae ed: he edt To ee wag mer * ta EN enen not t dee eee „e den a ee ee e ee eee bab Ono Aren i 17 * apie e eee ec ei 2 we * (On 55 ny e Dea pty NEN aD Shediac T oat ‘to aber ot mabe Scone tage 458 eee Tati ot we. bas n monte 8 Wilen adud- oer 0 werben, tite nei potuste aten che D 3 ot alemayiaes yi Nt bas ede ont Yo gor + N Sen Le cen r Nr Eee ; sits Boone a Tr | bmi Ade ban YHA Betun tu gor 00 bed agnes a0 Ses wat K cette i e met * we Ba Ae . Iod edt wort atidogeh Lisde te akon eed oF 1 10 or oe te | boss isvaye" to Poona El dn ge oft 8 i eens ot of ts ent Yo eee Boa „Sep ae eee eee eee ee oi OF bag een ".abowory, diss apie s a0 eee, 2% ee donn 7 9. N ö 0 i 0 . N WN 35 We have just completed, from money obtained from this source alone, the planting of three hundred and thirty thousand bushels of clam shells as Yeultch" in various selected spots. Practically all of our shells are now being planted by the hydraulic method and it hes been found to advantage to use two or more pumps to each barge when unloading. We are also using some of this money in transplanting oysters from over-populated reefs to arees where new reefs can be made of better quality oysters. We ere endeavoring in certain areas, where oysters are growing too thickly and in clusters, to use dredges with the bags removed to drag the reefs and break up the clusters, which appears to be a step in the right direction. A special seismic section of the Division of Oysters and Water Bottoms was organized in 1939 for the purpose of preventing loss of oysters, fish, shrimp and wildlife due to seismic exploration. Intergration of the inten- sive search for oil, based upon the use of explosives, and industries de- pendent upon oysters, fish, and other forms of life sensitive to shock waves was necessary for the economic operations of these industries. Regulations now in force are based upon findings obtained from a public hearing held between Department officials and counsel for the Department, together with representatives of the oil interests and their attorneys, end representa- tives of the fishing and wildlife interests of the State. It can now be stated that efter more than six years of seismic operations in the State, both the oil companies and the seismic exploration companies have given their wholehearted support to the Department of Wildlife and Fisheries in its endeavor to protect other naturel state resources. This is well illus- trated by the fact that today we heve fifty-five seismic exploration parties operating in the State. A conswation agent is assigned to each of these parties who renders daily reports of their activities to our Department. The salaries and expenses of these agents are borne by the various oil com- panies and all agnts are hired and fired by the Department of Wildlife and Fisheries and are responsible to said Department. I have with me, for any of you that might be interested, 2 number of sets of our seismic regulations together with handbooks which are given to each agent for his instruction and guidance. The Oyster Division uses for its patrol work a sixty-three-foot twin- engined Diesel-operated boat with e crew consisting of captein, cook and engineer. 4 fast speed boat tender is part of the equipment. The crew of the boat spends its entire time patrolling the oyster beds of the State and enforcing the oyster laws, noting the condition of oysters in various areas and when any exceptional mortality occurs in any area the main office is contacted so that biological examinations may be made. deter Noce of ov 1 ote node erb aki? e Ban ,Hxιüaͤͥe r be ne ro . eam ous pas on l e ty dena e vig Prentiss Dea beten ur en u, eee eit yo. bo dg LG sia won 4 . 1% 4% ike (ithe . ne r TO o a e biwet cepd ged th Dae eee EY ae NG pte ‘ation batte, oa ene oy BW Ses oF . » Bot ae etd. nnn otaiv — . dnt Sato ete nt Serhat oa; n 08 ura gate at den Se a a ab ga 0 oF e. eee odd qu A ee Bre i | 7 atataye mm 4 8 r wise ds od 26 Sb ed aso eser wou. 1 0 if dps nersi bn brvte yo 10 ‘aptatwtd oi 96 ations olmitee tide 4 deed — 145 ee r e e to tor Set at 9 now Ae git een „ut ot oub OTLB Lowe wan gt rien a3. aoviadtonte tt gest acl ae . ee otli to autos tate, & aint (erateyo aogy pal ee -Goitfavtat eaodt to ae ehe eee oft tot yresesten 8 b F n atin sodtegot ,dnomasqed ot 10d foopuca Gas alates tto eee satiteretyet has yeyontotis tia? bos een Lb vitae 40 d. n ndo 91 eee ott To eee eee bas t e e en e en, an edt at nous οe e to Poy a Bots exon teste Salt be, ov ovad eeimsqmoy notterolgss e We bus svinequoa Sto ot Bi Ses das. et2LbLIW Yo saommregod ee saa bot toone Laity in flow ef ict -soossonet atate eee eee erg oF abba pest r F oval Gy WAnO? Faris tos ofF! fo ideo oF bongless si these un PA sotst® off a grt ee roco wo of weltivitos thei? lo N NI obne ow gal e otzege BEER Bo Reonogxe dae selustan Bus anten 2 eee Su yt an Bars b Git ene ee e ee E « toqay edt a fs Ge ad eee omen entet tags end 10% ee * Baw eek ews ene bontetutem sen moitibsos at eres ot * edt Baqqoks Riese | r ythatleg edt @iom eono code YeM to 59, Rewwied Letevod seals «temas tew Yrov « edt No Sequota a alan Midieds of sc jtemqud To dae odd Livny ae totaxp 4 eethutG e edd to tees add vo Fee, *. Due e Dig nee“ wots ot Las dom ots renale ue ae ie to ee aidt ot eee eee eee e to Wire ad? mi stouborg dee .de tn % paitves dn bus „snes ast Butnwsge. 6 dee stat sit Ix tevew He ru as rs gsHG TG bas ag nẽ,jjꝙ as Yilever doldw eg to οπ⁰⁰·˖οmm itetw ,wteteyo Ser sem fr dent Lev bre amsoed nooe Bus Yfotakbanni rstew be edt aatsoLl neged beloud ‘em ylleiew tettam. bikee ed? to cea * Gos ee * —4 Bite ob o¢ moped von Teds va vd 95 851 tasvreq 8? of O mont edsα bed Yin bed toog Hove af etew bend som bed dent ele oF Joptoltiwa ai oh. taemon out ee en Ken 2D a a e e da den boden ad of 24% anew Guss 44 The extent of the affected area went beyond the "Head of the Bay” bars, and included many of the oysters in the Chester River, most of the bars on the Bay side of Kent Island, and a major portion of the bars in nne Arundel County on the western shore of the Bay. The mortalities were not as severe below the “Head of the Bay“ bars, but the condition of the oysters was so poor that they could not be marketed. The parts of the Bay and the tribu- taries below the above mentioned sections did produce many oysters, and made it possible for the State of Maryland to maintain production figures approx- imately equal to the 1944-5 season. The sad part of this season's losses is more profound than appears at the first glance. mong the areas affected were bars being developed as part of a program by the Maryland Department of Tidewater Fisheries for re- building the grounds of low yield and the pertielly depleted areas. Most of these planted end cultivated areas are in the Bay proper, but several others are located in the Chester River. During 1943 e set of oysters caught on shells planted at Love Point, Kent Shore and the bars in «anne arundel County. This set was aupplemented by seed of the same year setting transplanted from prepered seed areas. Many of these oysters had reached marketeble size and were part of the projected crop expected for the 1945-6 production. When the past seeson opened in September 1945, the condition of the meets was below the quality required for marketing on the basis of appearance end yield in pints per bushel, so the areas were not opened for hervesting. It was st first expected that the oysters would improve es the season progressed and the animals had more time to "fatten" after spawning hed ceased. They could then be harvested leter in the fall. This did not happen, and instead, many died. The survivors became progressively poorer as the season advanced, and entirely unfit for marketing. The fact that these oysters did not reach the market is no reflection on the State program, for the conditions occurring on these bars are unusual and they happen in- frequently. On the basis of umiarketability end loss through the heavy mortality, the State of Meryland oyster production for the season of 1945-6 was de- prived of over one million bushels. Approximately 40 percent of these oysters would have come from the reserved areas cultivated by the State of Meryland Oyster Management Plan. I the following table the detail upon which these figures are based is given. The Josses from the “Head of the Bey” bars are not included because that area cannot be rightly classed as a dependable source of oysters for the Meryland markets The losses on these latter bars, however, were heavy and represent considerably more than half of the population left there after the mortalities following the freshet of 1943 end the marketing during the fall of 1944. I believe I am justified in expressing a word of encouragement to close this otherwise depressing discussion. Some of the loss during the present season was due to unmarketability, and this may be recovered when the water conditions improve, and the subsequent improvement of the poor oysters. My tS — de gone Stn Bü ge ed Maeeg il ae ee , Sn May, 72 wait ant eA gr, ni ated add 2o eee Koe eae tot TOF 9 ewe 4 wee A an mentee odd te dae ott itd e NW „ bad aie to mn Oe eee bd Ven e 6 — e et e bes pee rede 88 — r a | e ascii OL COMDOTY katara a to 29 a iy or 1 is * 0 anaes 0 eens Sb az a at to 5 & > hevolewed yabud ated mated news oft Becht psc dy i ‘ ine son ee torewebh? I + Du gael: oat Y Satt «nore betotgeh eas Des lein wok 2 Bh Tse tind eee Ya ode ah Ome wanne bd an tikes ian datanle ana Ahe ‘to tir o COOL eee ee ceccod? ode sth ae at DM ME. wits ald deu, dd v een eee ee ae See We en oye peed qd E eren Aan F 9 Ae ay 1 Nen ee eee to Yall eee foe! ee ee 2 1 ds red bete gor eee U off tc Syed een ee tet neo ost (Bees. ro du yee b bony Un mic ent tale dne ‘ne Act c let d per vol iat edt W med Rate de ton eta epee ocd ea eee n avaig of fem ant an evetant br exeteyo tend? Doto.cxw ee we 4 Nee Sette “cette of ont gia beat ciate od? dun 8 1 Lib stur „ter aue at es Nera ad) got? Rigo dene IFAT cieood Mee onT .O98E : dat Zant ec? en eee e 96% gay Nan dad ese ; Ges ade ot oostocl tet Gee torso ent vill dom — 8 1 bug I νẽea N ee, tie" „ 1 ary i AY N aaa tend eat Ly. one et bow cee, de. eke „ ee abla A i. eee ot BR. st aa E =I eee Od eee 10 eters off ‘tno dre * 702 rode en Hoqu Ae ome: r node ads ol nrg eR Re Baek ane gig ae | a gk op tonauls wae: int beige gore. 7 00 22 55 sted? mo eee of? e eee ar iy Saw Matt ona Wange he q 55 d eee ond wahoo 2 12 aut 8rd ve N . + anti Win cao, eat i Table 1. Mortalities and production losses from the bars in the upper part of Chesapeake Bay, 1945-6, and marketable resicue. Baushels Name of Bar ay : Expected crop 1945-6 Mortality loss Marketable residue | Love Point 100,000 92,000 8, 000 9 Broad Creek 200 , 000 100, 000 100,000 a/ Gum Thicket 60 ,000 15,000 45,000 a Bloody Point 50,000 10,000 40, 000 a Chester River 25,000 10, 000 15,000 17% amne Arundel 15,000 5,000 10,000 ay Totals 450,000 232,000 218, 000 Swan Point 500, 000 300, 000 200, 000 ey. Anne Arundel 500, 000 150, 000 350,000 rh Totals 1,000,000 450,000 550, 000 eee Combined 1,450, 000 682, 000 768, 000 Totals af Bars cultivated State of Meryland Oyster Management Plan 4 Natural bars with oysters too poor to harvest OER Sea | Cal ee ns e Sono We e f e eee 3 nt wee 46 The loss through the heavy mortality on some of the bars is irreperable of eourse, but the cultch bought at this high price may be a small but useful element on the credit side in the rehabilitation. At the present time, hydrographical conditions are favorable for a drier season which should improve the salinity. The blame for the losses during the 1945-6 season may be put directly on the low salinity maintained throughout the whole of 1945 and early 1946. In the effort to explore ell possible causes for the poor condition and high mortalities, an independent study of the distribu- tion of the sporozoan parasite, Nematopsis, in the oysters from most of the bars in upper Chesapeake Bay was made by Miss Helen Landau, Biologist in the Fish and Wildlife Service. No correlation could be found between the distribution and the intensity of infestation of the parasite in the oysters with the poor condition and mortality. The period just past, usually the time when the upper part of Chesa- peake Bay is under the bad influence of the spring freshets from the Sus- quehanna River show by the records that it is the driest experienced since the Conowingo dam has been in operation. The overflow has been cut off ex- cept for power manufacture, and even this has been curtailed in order to maintain sufficient head to run the turbines. The salinity at the head of the bay has reflected this meager discharge of water from the dam and is now 10 parts per thousand higher than it was in 1945, and approximately 5 parts higher than it was in 1944. We still may get precipitation heavy enough to cause heavy run-off which would depress the salinity, but some ground has been gained by having a dry early spring. 4. short term depres- sion will not seriously harm the oysters provided a reasonably dry summer and fall permits the steady rise in salinity. I offer hope to Maryland in particular and to the oyster industry on the whole, for 2 substantial in- crease in oyster production from this area during the coming season. With higher salinities one may elso expect 2 better possibility of normal gonad development and a subsequent set to replace some of the losses just suffered by the oyster population in the upper Chesapeake Bay. On the evidence of our observations of the "Head of the Bay” conditions it seems appropriate to mention here that it would be more profitable to expand oyster cultivation in a southerly direction in the Maryland portion of the Chesapeake Bay end avoid trying to answer the question “is the head of the Bay a nursery or a death trap for oysters?" There is no doubt that 2 potential value exists in the head of the Bay and oysters will occur from time to time. When they do occur it would profit the State to remove them to safer areas to grow. A better oyster is produced where salinity remains higher and with less fluctuation than is found in the above area. * hoy ay ' to of 1 ak and aft m0. cee a terne eee lee nen o od You Sang aid? do ® Oe thence odd t. eee ae A, coxees Wh o tok olLdetare? et . nels a de Ken oct? eee hontatatem NOL wal, | Pr Rot eee ofdiasog Cle saudqae oF e ame leak “aes Un “RO sphere 8 ae seeks aa “Te Fann et eee ont , SEER tical , wee o. „ene deen et yd eben eee howe c tuen noltaLentes S i oily ah otfasieg atte he e 5 BL iy + 1 ad 08 Sa nage uit Ged wath ent Nl Kaen „e b HOLE ont work Acton guiisge wit 10 den bad wae elaine Sanaa te agit: tanec a et oY fede ebtoosd uae ee 1 "ste, De duo ood wot woltzeve ud? „dete asenοð at seed mand Tren anit eee gen . ida * aed ot uu ae 2 here Gud 99 5 85 ont du bge buon den Lip ren 0 e e n eee en Ysb u eee eet eee ee ene en o een enn eee en t Boalyson. of ego Jura 1 dae of een een be wet eee een 5 not eee pdt ao eee mee 1 5 = tense grimoo ed? A ce sore ald? mort, no peaeerS 7 | Pattee Lames to yt attotsaog 28808 a dere ae 5 n . queef oft Io aoe opalget oF toe We | 9s cad soggy Git * enge en a to Swett” o 10 200 h at eee wxow od Sioow $2 ee oxed TOR neatiog Une ran oud uh aotivettb ee eee oe Beat edt elf nada odd turmte of ackys? Dee Fast. ee of ah eee Yexetexs Go? cont Ge gee bee Like ene Mi We “lt. fo Leo qa ae ment ett oF afeta ott e een Aluvew e meee) tate ee ee bogubory ot eee eee „nN vo S a BU az nade HOW CAN WE PROFIT BY THE U. S. FOOD AND DRUG ADMINISTRATION HEARINGS Curtis D. Newcombe, Director Virginia Fisheries Laboratory Yorktown The extent to which oyster packers may profit from the recent hearings of the U. S. Food and Drug Administration depends firstly on what added sig- nificance they have been led to attach to hand ing and packing procenires. I think that many have come to realize more than ever before the bad effects on oysters and oyster markets of excessive contact with fresh water or boo great variability in counts or excessive emounis of shell fragments. The need for a standard of some kind is probably evident now to many that before the hearing considered standards unnecessary. Hence, it is likely that the Hearings have resulted in giving added significance to Standards in this industry. The extent to which the Hearings have been profitable depends, secondly, on new information that has been provided by the various Federal, State, and private agencies. Jfter listening to carefully prepared testimony offered by the Food and Drug (Administration and by the several other agencies, I became impressed with the need for Standards of some kind, the need of the oyster industry for the backing of the established Federal agency for proml- gating standards - namely the U. S. F. D. A. and especially the need for more facts to serve as a basis for Standards. The oystermen of the different states do not yet have the needed records to define the type of standards that best suit the country as a whole (if indeed such can de found) or that are applicable to even one generel section. It is true that the various state agencies in cooperation with the U. S. Fish and Wildlife Service did a great deal in a short time but the job is too big to be completed in a few months. Likewise, the testimony of the U. S. Food and Drug Administration impressed me as lacking technical facts on essential aspects of the regula- tions, and, too, the evidence seemed to reveal a lack of appreciation of the practical problems which every oysterman encounters. I may cite an example of variations in oysters from two different parts of Virginia which clearly show that there is no royal road to generalizations as far as behavicr of oysters is concerned. The two localities where our observations were made were near the mouth of Chesapeake Bay - salinity about 20 parts per thousand - and on the seaside of the Eastern Shove - salinity about 30 parts per thousand. Gellon samples were used. Bayside oysters shucked in a dry container had a drainage loss inmediately after shucing of 25.2 percent as compared with 8.2 percent of Seaside oysters. These same oysters were drained and weighed six more times in succession to see how much liquid they continued to lose on continued draining. As a result of being drained and weighed seven times in succession, Bayside oysters had a total drainage loss of 44.4 percent whereas Seaside oysters showed a corres- ponding loss of only 18.1 percent. 49 mndoeaath e t e * ark soe i . 5 6 eee ae — no See — om So bn 12 a 6 tok W Ten I o ‘te e od 22 vat CA 3 hoor odd dee bie: ., U. Da ode 8 Le ee elt To eee ee oft ee 0 „ oes tune ke wous elt ooze of abicoas eee Ovni "Gade oo (ero! af nob sto. eee it) alodw s em 2 — e be ee eee eee ot e eee eee e ee OF ade e obtibl n bas det „ a0 oct debe e ones % ah, een of OF pid oof aE Sot gen d ee ee e of Soe td ute ab Bre dect 16 .U ed? to din writ d ot Lingo add To pode Lenses ao ede Leckudbed gatxonl oa om ee wage ** rb ee d N @ fepret ot ese, ye ont oot Gitte’ nee Statnboone. macrresa yo. oda Wee N 4 a0 9 Seen ner? a diene nk pare éikiyereay, ae ct kae vate of hase dcn on e d tem Wed Lente 1 10 An ee ee gud er eee ee PL eee Ye L. boc | ce wicbdies - yal sene e to tem eit een stew een e e wWintiee ene me et to obne @AF mo Lite ® ipso tx, ee en rern G ee, eee eee er He hats? T t 0 rose | ani er Koch Wan sT AH coacterh @ bad Remhetimd yxh e ct Game ne 9 16 ratten bega d Kune £08 Un e e eee ae een eee wort coe OF Me ME ee pro KU un ben Arb oe e ee d enen of mh en neee oo eel OF eee godt 5 & bed NN N N obldyed Noe at sn, paves bedatow bun. e 0 bowody e rogge aan Innere d. d. to eae — 4 N en LBs eee e it |e 48 These findings were supported by other experiments in which oysters were shucked into containers containing 25 percent of fresh water and 75 percent of fresh water by volume. The data show clearly the difficulties that are likely to erise in an effort to establish Standards that will apply equally well in both regions. In eny attempt to promulgate uniform handling procedures for different areas, such differences as those given above cannot be ignored. Pertinent date on how oysters respond to different handling procedures, and, soo, on what constitutes the best practical procedures for the different sections should be mede known to the oyster packers end to the regulating avthorities. Both groups stand to benefit from strict adherence to such regulations. The oyster growers can benefit from the Food and Drug Administration Hearings by taking steps to get a factual basis for needed regulatory measures. The subject of uniform count has been discussed at some length. Our observations have not been comprehensive enougn to permit generalizetions. It seems clear, however, that the counts are more uniform in some houses then in others and thet concerted effort by the industry will result in sig- nificant improvements. Preliminary observations were made on the number and weight of shell fragments in individual gallon semples of "Select" and "Standard” oysters. Standards, as expected, were found to contain far more bits of shell than Selects. In one instance a gallon semple of Standards contained 139 shell fragments which weighed 24 grams, the largest fragment being one end one-half inches in length. The remaining samples were lower, one gallon of selects containing only 1 fragment which weighed 0.5 gram. These extremes are cited to indicate that there is a large variation between different plants and be- tween different days in the same plant depending on the experience of the workers and the oyster stock. 48 in the case of the problem of getting reasonably uniform packs, the oyster packer could, seemingly, accomplish much through constant effort to reduce the amount of shell fragments. Doubtless, the Hearings have resulted in improvements in more than one plant by making the operators increasingly aware of the 6ffect on the quality of the oyster pack of excessive contact with fresh water, excessive blowing, and excessive quantities of shell frag- ments. It would appear that such a step should help improve the demand for oysters. Furthermore, without effective regulations the progressive packer is likely to be penalized by the careless pecker who is relatively indifferent to the quality of his product. The importance of quality and not just size as a basis for grading has been stressed and deserves still more emphasis. ti . 1 Bümp enn | * * 1 öde OF has rote d 8 0 5 * ae . ode 50 N 4 e e Kot deen e Bake Pe 0 c 3 ‘od esa “Re ood” haw watebesoug eee grat * eee ee eee okt toh eee Leottoesq teed ond at | Pe wade ae add of bee axdilong totayo odt of seo aan od 6 yo ROT ee eee dogs ot eee folate aott sPromed ap & uo * a H DN Qe bua Soo% edt wort An, ang, 2 N nn, rns: ee beboun bon monet! ene, 77 e ae! 1 10 L peed u eee e ern Münte wat tad 3 a Ant Ig Read on en Sotreanoy t ü exe le to gdadew bug tedtan 0 @bam otew anitayresds. ein eee “irebnast” bao “YoulaBMete ee Lee do Lg 1 ae ae tee to atid een tet ee o baue Se beten a8 a draht fies CL hertatnce abiatuase A Tse nollsg « hn nt 40 Maden bith oto guked See 1 0 fal ody nists 8 | es daa Yo mot kee eno e whew eolqone 15 vif 8 ae 0 Dette goo eee ined? eg ee Beg en dotdw 5 T Mose aten deat ng er r S 8 ab, wt Jens © 5 ie oo to wage kae ad ue ackhasqeb foolq omee edt ae tt oars ont yeti sonore dice wenn Wen 2 ete 7 ot henne neue co derne Kn fetignoors Na e eee oved eee ee ee eee e eee ie fe ¢iantenssont e ene off Hidde YO ned eno ni en eee ven s, Tat cd one to sosy Te edt to Nai e go a cag Te 4 ss We eee to: en anne bas ae 1. . sie” Pi rot bai wut 80 gun en gota 8 — at 2 een outtsetgory eft oneideluget evitootte today eee vod Ga, eb oxy unh nen * ve best se ins x07 okOad © 48 n jon ane vr 49 I suggest that the Oyster Grower's Institute keep this whole subject of Standards alive by designating a committee to work on the projeuwt. 4 function of the Committee might be to stimulate and coordinate the investi- Batons needed to provide the necessary facts and to cocperate with the governtient agencies in assuring adherence to the desired standards of hand- ling and packing oysters. By keeping the packers more conscious of the ill effects of long contact with fresh water, of excessive riowing and of large numbers of shell fragments, a better oyster pack can be assured. BACTERIOLOGICAL OBSERVATIONS ON OYSTER GROUNDS OF THE HAMPTON ROADS AREA P. Arne Hansen, Bacteriologist, U. S. Fish and Wildlife Service Every oysterman is confronted with a great many problems in securing the best possible product for his market. One of the many obstacles which he is facing is the difficulty in finding adequate planting grounds in a locality where the oysters will fatten quickly and where sea water is suf- ficiently clean to meet the requirements of the U. S. Public Health Service. It may be added that the oyster grounds should be, of course, at a convenient distance from both shucking house and seed beds. The massive increase in population in the Hampton Roads area, especially during the war years, has been responsible for adding more acres to the already extensive restricted shellfish producing area with the result that the oyster growers have been practically forced out of the lower Bay between Willoughby Spit and Little Creek, an area of 3,847 acres. The monetary loss in production of market oysters is difficult to estimate exactly, but for the entire Hampton Roads area, it may well exceed 2 million dollars. Besides the actual decrease in the production of marketable oysters, there is an additional loss in the value of oyster bottoms which have been carefully improved for years by shell planting and which represent a considerable investment. The loss of oyster producing bottoms has caused deep concern to the oystering industry of Virginia. The Fish and Wildlife Service during the last 18 months has carried out studies on the trend of the pollution in the lower Chesapeake Bay with the object of finding areas free from objectionable contamination. Foods consumed in a raw condition, especially such which are of nitro- genous, non-acid nature, are of particular concern to public health officials. Since shellfish belong in that category, much has been done to safeguard the public and to dissociate the shellfish trade from the slightest suspicion by excluding from the market any shellfish which might possibly harbor potential danger. State officials, in cooperation with the U. S. Public Health Service, are continuously surveying shellfish waters to ascertain their suitability from the Public Health point of view. The degree of safety of shellfish waters is evaluated in terms of “Most Probable Numbers” of coliform bacteria, abbreviated M. P. N. This group of organisms in itself is not dangerous to human health, but it is universally associated with the excreta of humans and warm blooded animals which may carry organisms that are dangerous. Coliform bacteria are not present, at least not in significant numbers, in localities which have not been exposed to recent pollution. By planting definite amounts of sea water in suitable culture media, the number of coliform organisms can be fairly closely estimated. This quantitative method has become very widely used because it affords a fairly direct way to determine pollution. The most direct approach; namely, 50 * in on le * ih TOF lea i { 1 that 1 e N : N e g 1 7 es ten” 3 N 1 ** 7 1 MI on 1 4 * ic + 1 3 * daes sore Fegg ige ABA, BAU e 7 , ve) pom ens al nene N Lale a8 58 * a 2 * : ; 4 N 7 75 1 Mes ho py cies * p Poot a Peg ‘gh SB eee tenet, ekt en ya 0 ae at aao {sxottibbe tia af oat wu Sho okt ba et o bevorqas vA ee feed evad doldw e Ahe 86 wtomMeovnl elcetedianon a jnanomged dokiiy ee — ode or ale deb foave ead amotdod ufa ab W 6 i, a StS edivees td Bus dart ent . apbataatl To. 4 = | ‘a nt aotiwflog odt to dase ent ao tos too eee gail. eke Ae e Se asets a 1 e * mali nigh 4 ve ‘ mi ee Yo sto feld toni Sed id 2 ot 22 2 0 2 dttned Sd of eee eee 2 18 aS o o908 aed sad doun ,\yioseted tong gl a i — Hototvede d eg le ag ort vbext dprtilods eig 3 5 ‘bas 5 Lstenssog todtad XIdtesog enn doldw dabtifeds yas ee ont goat 2 va d otidud .& te At goltasogoo? at dn, otere dan tus teat, alone or at de 1 Cee dee e eln te datos Anton oid facil” to arte af petatlave ak Se na AL tons ‘to Wels de E de gien aur H. , n betatvoidds ,sinetosd oa ‘to: May eileerovtny et ti gud giitieed cauid of evoregash | Tem do idw atlanta Sebookd miow bap, anomvd to ‘ to ,dnesetg toa O49 ottagosd cmotiied paint 518 Nen aka . botogze seed von ern dt bebe at eee age be dante as „Kc tu at tatsw see 10 atnucins aatatted gattmely we... ee sbotembies: Ylopofo. ylrist od aap aghinvgie mroittog fo eck ead „ 8 ebtotts J vaseped Dea YLobiw Ne e end bolted ee emen pioworggs tosrlh tom eaT crn ene 09 dun 90 51 the counting of dangerous pathogenic bacteria, is not practical. Instead of testing for these, we have chosen to discriminate simply against all intestinal bacteria. According to the standard established by the Public Health Service, an M.P.N. of coliform bacteria in excess of 70 per 100 ml. should place a water as a moderately polluted, and such water areas should be considered as pol- luted and restricted for shellfish production. If the value of M. P. N. would remain more or less constant at the same sampling station, the work involved in testing would be of relatively simple nature. The task of the investigator, unfortunately, is made quite complicated by the fact that numerous factors, such as temperature of water, state of tide, recency and amount of precipi- tation, wind direction, presence of nutrients or inhibitors in the water, and still other influences, govern to a very considerable degree the number of bacteria present. Due regard must be given to occasional occurrences of very high numbers, hence it is prescribed that the median (the middle value) of a large set of data be used for expressing the just figure. The varia- tions from one sampling trip to another are particularly pronounced in the Lower Chesapeake Bay where sound judgement can be arrived at only after pro- longed and all-year-round sampling. The field laboratory at Hampton has been studying the progress of retreat of the sewage front in the lower Bay, ex- pressed in terms of M. P. N. The restricted area studied, between Fort Wool, Willoughby Spit, and Ocean View, slopes very gradually from the northwest boundary where the depth is 12-15 feet to 22-27 feet at the eastern border, the main part having a depth of about 20-24 feet. North of this region, at a distance of about 2000 yards, is a deep water channel, an important shipping lane, varying in depth, but mostly around 40-50 feet. Naturally enough, the pollution from the Hampton Roads area follows in some measures, as experiments have shown, this deep water channel being washed back and forth by the tidal wave.