ae a are de tla ee ah Ch AO ee ee ee ee tee cme & — sock trie emets am “ — : ’ a es news - wed “ . “ a - are . Fe te nme: AN hoe PRE Paes Pet © oe . rere ~~ inteote presen ee Seer erere errs wena : aon hetwenagee wie esas bone rnsemsnpnrmnntro tree gnee meen ene anew eeee = ooo mw : Maaco = phoamdcbUngsrae aceoes - tet ge nat 27 aa ay rere” “ darn PEM Coe Pea pep erry Are rete Arcee i) eee ae artech Sena Algae Pe ~Sarenteatey inna, rw ST lee Bet eet: Steen oe ete eit: eer a eins oe et om Nts CP ENA PASEO al line eet eee a leh Bn ng gee Ee Tle : hy “as uy eisiiin 7 GEORGE V SESSIONAL PAPER No. 38a A. 1917 SUPPLEMENT TO THE 6th ANNUAL REPORT OF THE DEPARTMENT OF NAVAL SERVICE, FISHERIES BRANCH CONTRIBUTIONS TO CANADIAN BIOLOGY BEING STUDIES FROM THE BIOLOGICAL STATIONS OF CANADA 1915-1916 PRINTED BY ORDER OF PARLIAMENT. OTT a Wk PRINTED BY J. pz L. TACHE, PRINTER TO THE KING’S MOST EXCELLENT MAJESTY. 1917 [88a—1917]a “7 GEORGE V ' SESSIONAL PAPER No. 38a A. 1917 THE BIOLOGICAL BOARD OF CANADA Professor E. E. PRINCE, Commissioner of Fisheries, Chairman. Professor A. B. MACALLUM, University of Toronto, Secretary-Treasurer. Professor L. W. BAILEY, University of New Brunswick, Fredericton, N.B. Professor A. H. R. BULLER, University of Manitoba, Winnipeg. Rev. Canon V. A. HUARD, Laval University, Museum of Public Instruction, Quebec, P.Q. Professor A. P. KNIGHT, Queen’s University, Kingston, Ont. Professor J. P. McCMURRICH, University of Toronto, Toronto. Dr. A. H. MacKAY, Dalhousie University, Halifax, N.S. Professor J. G. ADAMI, McGill University, Montreal. 7 GEORGE V SESSIONAL PAPER No. 38a CONTENTS. I. The Winter Plankton in the neighbourhood of St. Andrews, 1914-15... TH. BIN iy IV. Vi WEE VIII. IX. By Professor J. Playfair McMurrich, M.A., Ph.D., Professor of Anatomy in the University of Toronto. (With table showing Plankton Distribution.) Diatoms and Lobster Rearing. . A. 1917 Pace. aa! By Prof. W. T.. MacClement, M. i D. So., Once Uaioe Wigesion (With six figures in the text.) On the Seales of the Spring Salmon.. By C. McLean Fraser, Ph.D., Curator Pacific Coe ‘Biological Station, Departure Bay, British Columbia. (With four Plates and two Graphs.) On the Life-History of the Coho. . By C. McLean Fraser, Ph.D., Curator Pacific Cases Biological Secon B.C. (With three Plates and six Graphs.) . An Investigation of rig ps a ae in Richmond ae lead Ops ae 1915. By Gales Melaon.. PhD, Biologist, ‘New ce ye Eaenaene Station. The Marine Algz of the Passamaquoddy Region, New Brunswick.. .. By A. B. Klugh, M.A., Queen’s University, Kingston, Ont. (With one Plate.) On Serially Striped Haddock in New Brunswick.. .. . : 21 39 53 79 86 By Professor Edward E. Prince, LL.D., D. Sc, ERS. C, etc., Dominion Commissioner of IF cheries, Ottawa. (With one Plate.) Notes on the era of the eis of pee and Passamaquoddy Bay.. By Pratason ce W. " Bailey, MAS Ph. D., ioe EIUS., Emeritus Professor of Natural History, University of New Brunswick. 93 The Geological Features of the St. Croix River and Passamaquoddy Bay.. 109 By Professor L. W. Bailey, M.A., Ph.D., LL.D., etc., University of New Brunswick, Fredericton, N.B. (With Map.) iii Ma hy evi 8 7 GEORGE V SESSIONAL PAPER No. 38a A. 1917 PREFACE. BY PROFESSOR EDWARD E. PRINCE, LLD., D.SC., F.R.S.C., et¢., DOMINION COMMISSIONER OF FISHERIES, CHAIRMAN OF THE BIOLOGICAL BOARD OF CANADA; MEMBER OF THE BRITISH SCIENCE GUILD, LONDON; VICE-PRESIDENT INTERNATIONAL FISHERIES CONGRESS, WASH- INGTON, D.C., 1907;AND CHAIRMAN OF INTERNATIONAL RELATIONS, AMERICAN FISHERIES SOCIETY. The series of nine biological papers, included in the present publication, com- prises a selection of the researches completed by various members of the scientific staff, last season, and includes some work done in previous seasons at the two Cana- dian Biological Stations, at St. Andrews, New Brunswick, and at Departure Bay, British Columbia. Several very important investigations might have been included, but are not really complete at this date; two bearing directly upon the utilization of certain fish- products for food; but they will be published in the next volume of “ Contributions.” The question of a serial publication, or of the issue of separate papers as they reach completion, has occupied the attention of the Biological Board, especially in view of die fact that some researches can be completed earlier for publication than others, and yet are held back in order to appear in the same volume with papers which for various reasons cannot be hastened. About twenty trained scientific workers from eight different Universities have during the past season attended one or other of the Stations, and all engaged in marine and fishery studies of special interest, and in most cases of direct value practically and scientifically. Purely scientific problems, while not neglected, have not formed a prominent feature in the biological investigations at the stations under the Board, and on many cecasions there has been official recognition of the value to the Government of the researches undertaken. This appreciation of the practical bearing on the great fishing industries of Canada, of their work, has been a great satisfaction to the staff. Most of them carry on their work without recompense from the Government, and in no case lias adequate recompense been possible. The main reward has been the satisfaction which original discovery in Science affords, the satisfaction of adding to man’s know- ledge of Nature and her resources, and of solving the pressing problems which the great industries on our seas and inland waters offer for solution to trained scientific experts. During the year 1915 Dr. Johan Hjort, Director of Fisheries, Norway, continued the comprehensive survey of the waters of the Gulf of St. Lawrence and the Maritime Provinces shores which he had commenced the year before. Such a fishery survey, having special reference to the herring, cod, etc., had been considered by the Biological Board in 1909, and the Board had decided to enlist, if possible, the skilled aid of Dr. Hjort, or some Norse expert to be selected by him, and, as Chairman of the Board, 1 wrote to Dr. Hjort on the subject. Professor E. W. McBride, who was then the representative of McGill University on the Board, followed up my communication, and Dr. Hjort replied recommending a qualified junior member of his scientifie fishery staff; but, owing to certain conditions involved, the proposal remained in abeyance. Two years later the proposition was revived by the Biological Board, who laid the v vi DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 matter before the Hon. the Minister because of the fact that the ordinary appropria- tion available was too limited to allow of a large expenditure upon such a fishery expedition. No final decision was reached until 1914, when the scheme took practical skape and Dr. Hjort, in the fall of that year, began his researches. During his second season (1915) in Canada he carried out a very elaborate series of investigations, and several members of the Biological staff took part, including Professor Willey, Dr. A. G. Huntsman, Dr. J. W. Mavor, and Commander Anderson and other officers of the Naval Service Department. A series of voluminous memoirs, most of them fully illustrated, is now in the printer’s hands, and the results of this important Atlantic Fishery Expedition will be of permanent interest and value. As in previous volumes of the Biological Contributions, I give a brief resumé ot the several papers which follow, for convenience of reference, and to afford a ready means of knowing some of the main points set forth by the authors. 1. Tue Winter PLankton, St. Andrews, 1914-15.—(Professor McMurrich.) Previous Plankton investigations have been carried on in summer; but in view of the importance, as a source of nutriment for marine fishes, of the minute organisms floating in the sea, it appeared desirable to study these organisms in winter, as well as during the warmer months of the year, and Mr. Arthur Calder, a permanent officer of the St. Andrews Biological Station, made collections from September, 1914, to May, 1915. About twenty stations were visited regularly and suitable plankton nets used at the surface and at a depth of three fathoms. The depth and temperature (of the air and water), and the condition of the tide, were recorded on each occasion. Pro- fessor McMurrich points out that the collections at three fathoms depth showed greater abundance than near the surface; but the finer net used at the latter level may have influenced the result. The author grades the occurrence of the different species identified by him as “ abundant,” or “ frequent,” or “ occasional,” or “rare,” and a study of the synoptical table, at the end of the paper, gives at a glance the comparative results. Among the microscopic plant-forms, the sub-globular Coscinodiscus (four species) is most constant, but it increases in abundance as spring comes on. Next, hut much less constant, is Biddulphia. Chaetoceras, four or five species, occurs throughout the winter near the surface; but Thalassiosira and Rhizosolenia become suddenly most abundant in May and April. Ceratiwm and Peridinium, several species, were not frequent. Curiously enough, some familiar animal forms seemed to be absent in winter, euch as the Foraminifera, Radiolarians, and Infusorians, a few of the latter only ceeurring. Similarly Hydroids, and Echinoderm larvae, were rare in contrast to their fcequency in summer. Higher animals, e.g., worms, mollusks, and the like, were rare, one Sagitta being taken on January 1st, and a number of Plutei, and Holothurian ova and larvae, in April and May. Minute crustaceans form, as a rule, a most abundant element in the zoo-plankton, and the Copepods or water-fleas appeared during the winter to be most constant, very few of the Cladocera being taken (viz. a species of Podon about the middle of October at three fathoms depth; Temora, Harpacticus, Zaus, etc., being abundant or frequent, but Calani, species of which the rarest forms were Parathalestris Jacksoni, not before recorded in west Atlantic waters, and a single Halithalestris. Larval crabs and allied forms were rare, no lobster fry occurred; but Tunicate larvae were secured early in November and January, and Appendicu- larians in October. Only a few fish eggs and one small shore fish (pelagic stage) were obtained. The winter plankton in these waters would not appear to be so abundant or varied as anticipated; but it may be that, by using modified nets and by more extended work, areas of plentitude may be discovered to which the schools of young fish resort for feeding purposes. PREFACE ; vil SESSIONAL PAPER No. 38a 2. Dratoms AND LopsterR Reartnc.—(Professor MacClement.) Professor Knight’s laborious researches have shown that efforts to rear lobsters through the young stages in hatching ponds have been hampered by several difficulties, one of the most serious being the diatom pest. After hatching, larval lobsters crowd near the lighted surface layers of the water, until after four or five moults they seek shelter at the bottom. While under the influence of sunlight they become loaded with - microscopic plants, the diatoms forming a feathery coat as it were, and so incom- mode the floating larval lobsters that they were observed to sink to the bottom of the boxes used in the experiments at Long Beach, Nova Scotia. After a description of the structure of diatoms, and of the three or four species chiefly affecting young lobsters, the author dwells upon the two principal methods of combatting the pest, viz., by copper sulphate solution, which proved fatal when only 14 to 2 parts in three million parts of water were tried; and a second method, i.e., the screening from direct sunlight of the rearing boxes. Under this latter method larval lebsters loaded with diatoms soon lost a great many of them, and they moulted earlier, viz., in nine days, whereas the lobster fry not shaded from sunlight did not moult until the thirteenth day. Licmophora was the chief pest, but a list of nineteen species of diatoms occurring in the boxes is given, and the relation of the plankton to the sessile diatom pest is interestingly explained. 3. THE SCALES OF THE SPRING SALMON.—(Dr. C. McLean Fraser.) After reference to other work on fish scales, as affording information on the growth of fishes, Dr. Fraser states that the rings of growth in the Spring Salmon or Quinnat are much more regular in arrangement than those of the herring scale, and closely resemble the growth in a twig of wood (in cross section); the rings being closer and more compact in winter (the “winter check”), whereas from late in April to late in November the rings are wider, like the looser texture of the summer growth in the twig. Dr. Fraser noticed between March 17th and April 22nd, and between November 27th and January 5th, there were in many specimens evidences of retard- ation of growth, as Einar Lea had also noticed in the Norwegian herring. Careful tests made by the author did not show any relation between the temperature of the water and the retardation or the acceleration of growth, and the “graphs” given in the paper fully confirm this negative result. Nor does variation in food-supply appear to explain the phenomenon. An exhaustive study of the growth of the fish was made from the time when the fry (14 inches long), not yet provided with scales, descends to the sea. At the end of the year the fish are 10 inches long usually and weigh about half a pound. Not all the fry descend the first year; but some remain, and acquire their scaly covering in fresh water. The summer rings are close together, so slow is the growth of the fish in fresh water, and the two types of fish are remarkably contrasted even when both mingle in the same schools in the sea. Thus, the fish which reach the sea from March to April in their first year, may be 203 inches long and weigh 4 pounds or over; but the delayed fish are only 14 inches and of a weight of a pound. In the third year they are respectively 284 inches and 14 pounds weight, and 23 inches and 6 pounds weight; while, in the fourth year, they are in length 33 inches and 30 inches, and in weight 22 pounds and 16 pounds respectively. The more rapid growth of the “sea type” indicates that the retention of the fry in ponds is a mistake, and based on lack of accurate knowledge of the peculiarities of the Pacific Quinnat Salmon. Four very graphic plates and two diagrams establish the important conclusions reached by Dr. Fraser. ! Vili DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 4. Own the Lire-History or THE Cono.—(Dr. McLean Fraser.) The author points out that the increasing commercial value of the Coho or Silver Salmon (Oncorhynchus kisutch) in recent years justifies a thorough investigation of its life-history, rate of growth, etc. The spawning grounds are usually a short distance from the sea, and not at the head waters, as in the case of the Sockeye and the Spring Salmon. The eggs hatch in three months and the young fry wriggle up through the gravel early in April, and work down the rivers as the yolk is absorbed, and early in May many are near the mouth of their natal streams and creeks, but do not appear to migrate into the sea until the following March, or even later. The alevins measure 13 inches; but when they are about to enter salt water (nearly a year old), they measure 2 to 23 inches about; and eight or nine months later are 10 to 12 inches long and of a weight of 12 to 14 ounces. When 2% years old or thereabout, they may be 3% to 164 pounds in weight, and from 18 to 31 inches long, so great is the variation in growth. They are now mature and make the short ascent to their spawning grounds. Dr. Fraser proves that the opinion, which has been frequently expressed, that coho live for two or three years in rivers feeding 6n trout is absurd, and the reverse is much nearer the truth, for trout gorge themselves with coho eggs and devour the fry mercilessly. The Dolly Varden trout (S. malma) is the chief culprit. The mature coho feed actively until ready to ascend for spawning purposes; the shrimp-like Schizopods being their main food, but larval crabs, young herring, launce, and ecapelin, form also part of their diet. Dr. Fraser’s investigations correct the conclusions of previous workers as to the migrations and development of the coho, and three points, with which his report concludes, are of the highest interest to practical fish-culturists, viz., that the hatching of coho in fish-culture establishments is most desirable to avoid the wastage due to trout-depredations; and, secondly, that the retention of coho fry in rearing ponds must bring the best results, as almost .the whole of the fry hatched naturally remain for a year or more in fresh water before descending to the sea. Lastly, early coho fishing operations are a loss to the fishermen and the canners, as the eoho vastly increases in weight during the summer of its third year. 5. INVESTIGATION OF OysTER PROPAGATION IN Ricumonp Bay, P.E.I., purine 1915.— (Dr. Julius Nelson.) The author, who was long prominent as a State Expert in New Jersey, U.S.A., agreed to carry on some special work in 1915 on the Richmond Bay Oyster Beds, P.E.1., and obtained some very remarkable results. These are difficult to epitomise owing to the very detailed nature of the investigation. The decline and extinction of certain areas are due not to the elevation of the beds, geologically, or by annual accu- mulations of debris, but to other causes. If the coast has been sinking, as seems prob- able, the intrusion of colder northern water may have lowered the temperature and the salinity may have been affected. Too much stress, says the author, has been prob- ably laid on salinity, for oysters can endure much variation in that respect; but temperature, oxygen, and currents, are of importance. Ice and snow also are unfavourable. Shallow water is favourable for propagation; but, in winter, results in oyster destruction; hence man can aid by oyster culture, especially by transplanting young oysters from shallow flats to deeper water, before winter comes. The main cause of destruction of beds has been improper fishing. Were private culture general each man would conserve the oysters, and fish them properly. Dr. Nelson calls attention to the fact that a large spawning oyster produces annually 60,000,000 eggs, and he estimates that an oyster bed readily produces ten to , fifteen millions of young for each adult present. In five years a bed should be ten million times larger; yet beds are decreasing and decaying. PREFACE 5 ime SESSIONAL PAPER No. 38a + Unfavourable causes are noticed, viz.:—(1) Eggs must be fertilized within a quarter of an hour of ejection to undergo normal development; (2) Eggs may be pre- vented from settling by agitation in the water; (3) Floating enemies such as water- fleas, and the young of other shellfish, devour them; (4) Owing to the sweeping of the tide, twice daily, myriads of oyster fry are lost; (5) Slime, silt, ete., prevent the fixation of the spat to dead shells and other “ pulieh ”: (6) Boring sea- Lele starfish, bottom fishes, ete., devour the oysters, and, laser man himself destroys them. Systematic plans of conserving oyster beds are then detailed, and the necessity of oyster leases urged. The methods adopted for testing the special areas examined in Richmond Bay are described, and the numbers of oyster larvae obtained in definite cubie quantities of water. The maximum found was two young oysters to one quart of water in Grand River. This small yield is contrasted with the profusion of oysters cn more southerly areas as in New Jersey, where several hundred young oysters per quart of water was very usual. Some oysters shed their eggs towards the end of July, but the date varied in different localities, fry ten days old being got on August 5th, but it continued until September, some oysters becoming fixed spat as late as Septem- ber 16th or 18th. To prevent the formation of bacterial slime, a number of shells were coated with coal tar, as a fine catch of spat had fastened on the tarred bottom of a boat the previous season. The result showed only two-fifths as many fixed young as on the uncoated clean oyster shell. ‘Ihe smooth and the rough side were equal in results, and the left valve attracted twice as many as the right valve, though in gaping empty oyster shells, lying naturally on the bottom, the right valve always secures more spat. Further experiments are desirable, especially with cultch coated with a cement composed of equal parts of lime, sand, and cement, as used on European oyster beds. Dr. Nelson’s conclusion is that 8,000 acres might be made productive in Richmond Bay, which covers 32,000 acres, and that a million bushels per annum could be produced were rational scientific methods adopted. €. THE Marine ALGAE OF THE PAssAMAQuUOpDy Recion, N.B.—(Mr. A. B. Klugh, M.A.) Mr. Klugh covers in his paper the area from St. Stephen, at the head of naviga- tion on the St. Croix River, to Grand Manan, and notes that the algal flora is boreal, but shows a marked “ inside” or mainland shore division; and an “ outside” division comprising the shores of what are called the West Isles, and due doubtless to the cifference in salinity. The “outside” waters have a specific gravity of 1-0235 to 1-0242, and salt content of 3-201 to 3-280, as compared with the “inside” waters where the figures are—specific gravity 1-0226 to 1-0235, and salts 2-99 to 3-202, as Mr. Copeland found. Of the Cyanophycee Mr. Klugh names twelve species; the Chlorophycese 24 species; the Phaeophycee 23 species; and the Rhodophycee 26 species. The features of the shores are shown in views on Plate viii, the gigantic Laminaria longicruris, the largest alga in this region, is well shown in a photo-figure, the specimen selected being five feet ten inches long, with a stipe 9 feet long. Dermocarpa prasina, and four other species of Cyanophycex, are recorded by the author for the first time in Canada. The habitat, and other interesting notes are given. 7. SERIALLY STRIPED Happock 1x New Brunswick.—(Professor Prince.) Specimens of haddock with four to six transverse black stripes are frequently brought to the Biological Station, and the author compares them with other species showing metameric bars, in post-larval or older stages, and he concludes that they are ancestral in significance, and not protective or illustrative of mimicry and the like. 38a—B xX DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 8. Notes oN THE PHYTO-PLANKTON OF THE Bay or Funpy anp Passamaquoppy Bay.— (Professor Bailey.) Professor Bailey continues his laborious studies of the microscopic plant-life of our Atlantic waters. He determines the species in gatherings made in successive months of the year, December excepted, and adds a list of diatoms secured in tow- nettings made by the Prince, the biological vessel belonging to the station at St. Andrews. He points out that non-planktonic species are frequently met with amongst neritic species secured far from shore, and the distinction is often, therefore, ill-defined. The gatherings in various months differ greatly, for while in January under twenty species were determined in the gatherings from St. Andrews to St. John, in August nearly eighty species were found. The Prince collections are similarly detailed, and interesting notes added including reference to a species of Thalassiothrix which is probably new to science. 9. Tur GEOLOGICAL FEATURES OF THE St. Crorx River anp Passamaquoppy Bay.— (Professor Bailey.) In response to a suggestion made to Professor Bailey, he has prepared a condensed account of the geology of the site of the St. Andrews station and its environment. The Upper Devonian rocks of red sandstones and conglomerates of the St. Andrews peninsula contrast with the granites of the Maine shore opposite and of Dochet island above the station, and the Silurian strata extending from lake Utopia and St. George to Oak bay, both sides of the entrance and both sides of Waweig inlet. The interesting features, largely Pre-Cambrian probably, of the Western Isles are also indicated in the paper. 7 GEORGE V SESSIONAL PAPER No. 38a ; A. 1917 THE WINTER PLANKTON IN THE NEIGHBOURHOOD OF ST. ANDREWS, 1914-15. By Proressor J. Puayrairn McMurricu, M.A., Ph.D., Professor of Anatomy in the University of Toronto. With the object of determining the general character of the winter plankton in the vicinity of the Biological Station, St. Andrews, N.B., the caretaker of the station, A. B. Calder, was instructed to make collections of the plankton during the winter of 1914-15, and to preserve the material collected in formalin. Collections were con- sequently made at frequent intervals from the latter part of September, 1914, until the end of May, 1915, and in what follows, the results of a qualitative study of the collections are given. Acknowledgment must be made of the conscientious manner in which Calder fulfilled the task with which he was entrusted, the collec- tions having been made with sufficient frequency to give an excellent idea of the character of the winter plankton, and the material being well preserved. Two coliections were taken at each station in the majority of cases, one at the surface and one at a depth of about 6 metres (3 fathoms), and at each station the tempera- ture of both the air and the surface-water was taken, and the condition of the tide noted. The only misfortune that occurred was the loss of the labels of some of the collections, chiefly of those made in the early autumn, so that these collections cannot be included in the table which forms an appendix to this report. Their omission, how- ever, does not modify the qualitative character of the plankton as shown by the remain- ing collections. In studying the collections, the volume of the material contained in each one was measured, and since nets of the same mesh were used throughout and the time of the towing was the same, i.e., twenty minutes for each collection, the amounts obtained indicate approximately the relative abundance of the plankton in the different gatherings of the series. Obviously, however, they furnish no indication of the absolute amount of material present in the water of Passamoquoddy bay, since no data were available as to the volume of water filtered through the nets during the towing. So many factors, uncontrollable in the series of collections under con- sideration, enter into the question of the determination of the absolute plankton volume, that it did not seem worth while to attempt an estimation of the volume of water filtered by the nets. The amounts obtained have, therefore, only a relative interest. One feature is, however, shown very clearly by the figures, namely, that with rare exceptions the collections from the 6-metre level were considerably larger than those from the surface. This may or may not have a bearing in the distribution of the plankton, since the conditions under which the collections at the two levels were made were not quite identical, the surface collections having been made with a net of finer mesh than that used at the 6-metre level. The greater fineness of the sur- face net may have caused so much diminution of flow through it, that much less water was actually filtered by it than by the 3-fathom net, in which case a less amount of plankton, even though its distribution were uniform at both levels, would be expected in the surface collection. In future series the conditions for the gather- ings at the two levels will be made more uniform, and it is hoped that a definite result will be obtained as to this question of distribution. Samples were taken of each collection and, so far as possible, the various forms observed in each were identified and recorded, an attempt being made to indicate 38a—1 2 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 the relative abundance of each form by estimating the frequency with which it occurred. Four élasses of frequency were recognized and termed abundant, frequent, occasional, and rare, the last being employed when only one or two examples of a form were found in a sample, the other terms explaining themselves in a general way on this basis. In the table these terms have, for convenience, been indicated by the numbers 4-1, 4 standing for abundant, 3 for frequent, ete. Seasonal variations in the character of the plankton: are revealed in this way, and a few remarks may be made upon these variations and on various forms occurring in the collection so far as they have been certainly identified. THE PHYTOPLANKTON. Less attention was given to the phyto- than to the zooplankton, partly on account of the inaccessibility of the literature necessary for the identification of the forms, and partly because the Diatoms which form a major portion of*it have already been discussed by Bailey." The form occurring with the greatest constancy is the diatom Coscinodiscus, which is absent from but a few of the collections throughout the entire period which they represent. With the onset of spring, however, it becomes somewhat more abundant than in the winter months, behaving in this respect like other members of the phyto-plankton. Four different forms of the genus have been recognized, which, with the aid of Rattray’s Monograph” and such other literature as was accessible, have been identified as C. radiatus Ehr., C. concinnus W. Sm., C. centralis Rattray, and C. fasciculatus O’Me. The first three species have already been recorded by Bailey, and may be distinguished from one another and from C. fascicu- latus by C. radiatus being the smallest, and having distinctly coarser markings and no central rosette or space; by C. centralis having a central rosette, but no signs of fasciculation of the markings at the periphery, near which are situated asymmetric- ally two apiculi; by C. concinnus having a central rosette, much finer markings than either of the others, these markings showing indications of fasciculation towards the periphery, and each fasciculating line terminating there in a minme apiculus; and by C. fasciculatus having a central space, and the markings arranged in fasciculi, each of about nine radial rows, the central one of which alone reaches the central space, the others terminating at successively greater distances from it. Next in order of constancy to Coscinodiscus, though falling much behind it, was Biddulphia, the most frequently occurring species being b. aurita Lyngk., although a much larger form with small scattered chloroplasts, probably B. mobiliensis Grun, was also observed in several gatherings. From October, until about the end of February, Biddulphia was rare or absent from the collections, but throughout March and April it was of frequent occurrence, diminishing again rapidly in May. Its seasonable distribution was, therefore, similar to that of Coscinodiscus, except that the latter is more frequently present throughout the winter months, reaching a maxi- mum frequency in March and April. Examples of CUhaetoceras occurred at rare intervals throughout the winter, becoming more numerous and more constant in April, and, it may also be noted, occurring most frequently in the surface collections, only having been observed in two occasions in those of the 6-metre level. At least four or five different species were observed, all belonging to Gran’s sub-genus Hyalochaeta.* 1L. W. Bailey. Some recent Diatoms, fresh-water and marine, from the vicinity of the Biological Station, St. Andrews, N.B., August 20-30, 1909. Contributions to Canadian Biology, 1906-10. Ottawa, 1912. L. W. Bailey. The Plankton Diatoms of the Bay of Fundy. Contributions to Canadian Biology, 1911-14. Ottawa, 1915. 2J. Rattray. A Revision of the Genus Coscinodiscus and some Allied Genera. Proc. Roy. Soc. Edinburgh, xvi, 1899. 8H. H. Gran. Protophyta in Norwegian North-Atlantic Expedition, vii, 1897. THE WINTER PLANKTON nn 3 SESSIONAL PAPER No. 38a The most frequent form was what seemed to be C. lacinioswm Schiitt with a single chromatophore, the foramina slightly constricted at the middle, and tke terminal sete marked by a delicate spiral line most easily seen in dried samples; spores were not observed. Somewhat less frequent was a spirally coiled form which seemed to be C. curvisetum Cleve, with a single chromatophore adjacent to the front of each frustule. C. decipiens Cleve was still rarer, but readily distinguished from the others by its coarser sete and the occurrence of four to six chromatophores, and a single example of a form with numerous scattered chromatophores, thus resembling C. teres Cleve, and another with two chromatophores adjacent to the ends of the frustule (C. constrictum Gran.?) were also observed. : An interesting seasonal distribution was shown by Thalasstosira Nordenskjoldu Cleve. Throughout October, November, and the winter months this species did not oceur in the collections, but on March 13 it suddenly appeared in considerable quan- tities. It was again taken on March 25 and 26, though not in any great numbers, but on April 4 it formed by far the greater bulk of the plankton, which condition persisted until the collections ceased at the end of May. Another genus that showed a distinct maximum of occurrence at the end of March and the beginning of April was Rhizosolenia, so far at least as its most frequently occurring species, R. setigera Brightwell, was concerned. AR. styliformis Brightwell was also observed, but only in one collection, and another form, which seems to be very similar to R. gracillima Cleve was also observed. This last form was observed on four occasions, October 16 and 20, February 26 and March 2, and on all occasions except the last it was found in collections made at the 6-metre level,- while it was absent,or at all events rare, in the surface collections made on the same dates and at the same stations. Whenever found it: was in great numbers. The frustules were long, filiform, without any siens of markings except a slight depres- sion close to each extremity, and were filled with small, scattered oval or circular chromatophores. The longest individuals measured as much as 2:2 mm., with @ diameter of 0-:0075 mm., and the great majority exceeded 1:0 mm. in length. These measurements greatly exceed those given by Cleve! in the description of the species, but otherwise the agreement is close. A species of Schizonema, and one of Fragilarva were also somewhat more abundant in the early spring months, and examples of other genera were occasionally observed, but no attempt was made to determine their exact identity. Of the genera so represented, mention may be made of Navicula,. Rhabdonema, Gomphonema, Bacillaria, and Campylodiscus. Of occasional occurrence also were certain filamentous alge, the only one that was identified even as to the genus, being a species of Cladophora, which, like many of the diatoms, showed a maximum of occurrence, its greatest frequency and con- stancy being in the early part of April, and being of only a few days’ duration. DINOFLAGELLATA. The most frequent representative of this group was the well-known Ceratium tripos (O. F. M.) Nitzsch, C. fusus (Ehr) Dujard. also occurring, though not quite so frequently, and (@. furca (Ehr) Dujard. was recognized in two gatherings, but only in very small numbers. Of the genus Peridinium, P. divergens var. reniforme Ehr. (P. depressum Bailey) was found occasionally, and was the only member of the eenus recognized. Dinophysis norvegica C. and L. was also observed, but only on one: oceasion. None of the Dinoflagellates occurred in such numbers as be important: quantitative constituents of the plankton, C. tripos only on one occasion being in sufficient quantity to be regarded as frequent. PIER ARS Cleve. On some new and little-known diatoms. K. Svensk. Vet.-Akad. Handl, xviii, No. 5, 1881. 38a--14 4 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 SILICOFLAGELLATA, Of this group only one form was observed, Distephanus speculum (Ehr) Stohr, and this only on three occasions. It was frequent in a gathering from the 6-metre level on March 6, but on the other two occasions it was rare (October 20, 6-metres) or occasional (March 2, surface). RHIZOPODA. No Radiolaria were observed. These forms being essentially pelagic, it seems probable that they would only rarely, if ever, be found in waters so remote from the open sea as those in the neighbourhood of St. Andrews. Foraminifera, too, were absent, a single Rotalia being the only one observed, and that in a gathering which contained a good deal of sand, indicating that the net at the 6-metre level had come into contact with the bottom. CILIATA. In addition to a Vorticellid that was almost invariably found attached. to the Copepod Acartia clausii, a number of ciliates belonging to the family Tintinnodes were observed. The genus Tintinnopsis was represented by at least three species, the most frequent of which was 7’. campanula (Ehy) Daday. Examples of a form which is probably to be regarded as a variety of this were found on one occasion, their peculiarity being that they tapered aborally much more rapidly than the typical campanula, thus resembling closely the form figured by Brandt! in his fig. 8, pl. xxi. A single example was seen of 7. ventricosa (C. and L.), characterized by its somewhat rotund “house,” tapering aborally to a blunt point and with the mouth- opening greatly constricted by a circular prolongation, which, in the preserved example, was horizontal in position. A third form, of which again but a single example was seen, was considerably larger than the others and had an almost cylin- drical form, enlarging only very slightly towards the mouth, and being rounded aborally; the length was about twice the breadth. In its general form it resembled closely that described by von Daday? as T. beroidea, but Brandt does not consider this identical with the form originally so named by Stein. Among the species described by Brandt the greatest similarity of form is shown by T. sacculus, but, unfortunately, the notes and drawing made of the St. Andrews form are insufficiently detailed to make identification with this certain. Of occasional occurrence, and in one gathering (October 20) almost frequent, was a species of Cyttarocylis, whose specific identity is also uncertain. It resémbles C. Ehrenbergi (C. and L.) Fol. very closely in its general form and in the fact that the cavity of the “house” is not continued into the aboral prolongation. This latter structure, however, is cylindrical in form, showing no traces of the three flange-like ridges which Brandt regards as characteristic of the species, although these are not noted by other writers. The surface of the “house” presents a very fine reticula- tion and has a minutely and irregularly corrugated appearance, most pronounced in the aboral prolongation. Near the mouth there is a narrow circular enlargement upon which follows a thin ring, sometimes single, sometimes partly divided into two portions by a fine line, as if it were composed of a spiral membrane with one and a half turns. The free edge of the ring or spiral is practically smooth, and the appear- ance presented is similar to that described and figured by Jorgensen* for his 1K. Brandt. Die Tintinnodeen. Ergeb. Plankton Exped., III, L, a., 1907. 2E. von Daday. Monographie der Familie der Tintinnodeen. Mitth. Zool. Stat. Neapel, vii, 1887. ‘ ’ 3. Jorgensen. Ueber die Tintinnoden der Norwegischen Westktste. Bergens Mus. Aarbog., 1899. we) THE WINTER PLANKTON 5 SESSIONAL PAPER No. 38a C. Ehrenbergi, var. subannulata, except that the turns of the spiral are much fewer. The length of the “house” was 0-26 to 0-34 mm., with a diameter at the mouth of 0.7 to 0-8. PORIFERA AND COELENTERA. What were taken to be sponge spicules were observed in a number of gatherings, usually associated with annelid sete. Their occurrence is sufficiently indicated in the table. Of Coelentera, the empty cups of Campanularian hydroids were occasionnally observed associated with Crustacean exuvie, and on October 29 and in the last collec- tions that were made (May 29) a few examples of Anthomeduse were observed, but unfortunately in a condition very unfavourable for certain determination. ECHINODERMATA. Throughout the winter, no representatives of this group were taken, but at the end of April and beginning of May a few Plutei were obtained which could not be satisfactorily identified. On April 6, a considerable number of ova in various stages of segmentation up to the blastula stage were found. They were somewhat opaque, and inclosed within a thin structureless membrane. They were taken also on April 10, and with them were then associated larve which could be recognized as belonging to some species of Holothurian. The general appearance of the ova and younger larveze make it exceedingly probable that they were younger stages in the development of the same form. The larve continued to be taken through April and May, and were a quite characteristic feature of the plankton during these months. Two Holothurians occur at St. Andrews that may be the producers of these ova, Cucumaria frondosa Gunner, and Lophothuria fabricti (Dub and Kor). The former is the more common, but the fact that the ova and larve have, when alive, the same brilliant scarlet colour that makes Lophothuria fabriciit so conspicuous, suggests that they may be the product of that species. ~ ANNELIDA, NEMATODES, ROTIFERS, AND CHAETOGNATHA. Examples of all these groups were observed, but never in such numbers that they could be regarded as important elements of the plankton. Sets of various forms which evidently were from Annelids were found in fair numbers in several gatherings taken after March 1, but of more importance was the occurrence of Annelid larve during April and May, never in any great numbers in any gathering, but sometimes reaching the grade of frequency indicated in the table by the term “ occasional.” It was not possible to identify the form which produced the larvee, but from their general appearance it seems probable that they represent some Spionid form. Small Nematodes were occasionally observed in small numbers in the spring gatherings, but no attempt was made to identify them. The same remark applies to the Rotifera, which were much rarer than might have been expected. Of the Chaetog- naths the only form identified was Sagitta elegans which was taken January 1, the identification of some smaller forms taken October 29 remaining uncertain. MOLLUSCA. A few veligers were observed, but so rarely that they have not been included in the table. The peculiar egg-capsule, probably Molluscan, having the shape of a broad- rimmed hat, which Wright described from Canso, occurred at intervals throughout the season, and sometimes in considerable numbers. Most frequently only the brown empty cases were found, though occasionally those containing developing ova were obtained. © DEPARTMENT OF THE NAVAL SERVICE 7? GEORGE V, A. 1917 CRUSTACEA. The Crustacea are the most interesting group represented in the zoo-plankton, both on account of the number of species represented, and for the fact that, in the majority of gatherings, they form the greater bulk of the material. It will be con- venient to consider the various forms observed under their proper orders Cladocera. Representatives of this order were found much less frequently than was expected, occurring in any considerable numbers in only one gathering, i.e., in that taken October 16, from the 6-metre level. All the forms observed in this gathering were representatives of the species Podon polyphemoides Leuckart. Copepoda. Forms belonging to this group were the most constant constituents of the plankton, being found in every gathering, with one exception, and usually in con- siderable numbers. It is noteworthy, however, that in the spring months when Thalassiosira became a prominent constituent of the plankton, the Copepoda became very much reduced in numbers. At least this was the case so far as the surface water down to the 6-metre level was concerned, the Thalassiosira extending to that depth, but it is quite likely that the Copepoda were present in undiminished numbers at levels beyond those occupied by the alga. The diminution of the Copepoda in the surface water coincidently with the appearance of T'halassiosira is clearly indicated in the table if one compares the frequency records for Acartia claust’and the diatom. Of the members of the family Calanide, special interest attaches to Calanus finmarchicus (Gunner) Boeck, on account of its forming so important a constituent of the plankton of northern waters. It occurred at intervals throughout the winter, but never in any great quantity, although in several gatherings it was present in sufficient numbers to deserve the term “frequent.” It is to be noted, however, that the plankton now under discussion was collected in the immediate vicinity of St. Andrews, and it is quite probable that C. finmarchicus may be much more abundant in more open water. Herdman in 1897! found it very abundant in the gulf of St. Lawrence and in the Atlantic off the entrance to the straits of Belle Isle, and my colleague, Dr. A. G. Huntsman, obtained it in large numbers in rather deep water off Eastport, Me., and off Grand Manan in September, 1915. The much larger OC. hyperboreus Kroyer was observed in only one gathering, and then only as a single individual. The fact of its occurrence is, however, of interest as it has not previously been recorded from Canadian waters. A third Calanid, Pseudocalanus elongatus Boeck, easily recognized by the absence of the fifth pair of legs in the female, occurred in about the same degree of frequency as UV. finmarchicus. Of the family Centropagide, the genus Eurytemora furnished two representatives, EB. hirundoides Nordquist and EH. herdmani, Thompson and Scott. Neither was abundant in any gathering, but both occurred at intervals throughout the season represented by the collection, and were occasionally “frequent.” MTemora longi- cornis (Mill) Boeck also occurred at intervals in the autumn and winter until the end of January, after which it was not observed. On the last date on which it was found (January 27) it was the most abundant constituent of the plankton. Tt is the family Pontellide, however, that furnishes the most characteristic feature of the plankton now being discussed, the form concerned being Acartia 1w. A. Herdman. On the plankton collected continuously during two traverses of the North Atlantic in the summer of 1897. Trans. Liverpool Biol. Soc., xii, 1898. ~ THE WINTER PLANKTON 7 SESSIONAL PAPER No. 38a clausit Giesbr. A glance at the table will show that this species occurred in nearly every gathering throughout the season, and that up to the early part of April it was almost always in abundance. Its reduction in numbers after that date in association with the appearance: of Thalassiosira has already been commented upon. Another Pontellid observed was the interesting J'ortanus discaudatus (Thompson and Scott) Giesbr. It was taken in several gatherings made during the autumn and early winter, but after December it was not again noted until the end of May. In con- nection with this form, it may be noted that Giesbrecht and Schmeil! question the correctness of Thompson and Scott’s original description of the endopodite of the first pair of legs being three-jointed. There is no doubt, however, that the original description is quite correct, discaudatus differing from other members of the genus in this respect. Of the Cyclopide, Ozthona similis Claus was the only form cbserved, and that in small numbers in but three gatherings. The Harpacticide have hitherto received but scant consideration in plankton Nests, partly, no doubt, to difficulties inherent in their identification. The excellent monograph of the family by Sars’ does away with some of these difficulties and, with its aid, it has been possible to determine the occurrence in the collections of a number of forms hitherto unrecorded from Canadian waters. The most frequent species was undoubtedly Harracticus uniremis Kroyer, which is readily distin- guishable from H. chelifer (Miller), among other things by the first antenne being nine-jointed instead of eight-jointed, and by the inner expansion of the proximal joint of the fifth pair of legs bearing four marginal sete instead of three. H. chelifer has been recorded by Wright* as occurring at Canso and also by Williams* from Rhode Island waters, where H. wniremis was also found. It iis possible H. chelifer also occurs at St. Andrews; indeed, certain forms were identified as belong- ing to that species when the study of the collection was begun, but the identification was made with insufficient literature and before access was obtained to Sars’ Mono- graph, and opportunity has not occurred for confirming the identification. It seems probable that it was erroneous in the majority of cases. A second (or third) species of Harpacticus was one which closely resembled that described by Sars as H. gracilis Claus, differing from H. uniremis by the greater relative shortness of the terminal portion of the first antenne and by the two t-rmin:] joints of the endopodite of the first pair of legs being confluent. Two species of Zaus were observed, distinguishable by the form of the fifth pair of legs. One was evidently Z. abbreviatus Sars, hitherto recorded only from the coast of Norway and from the islands north of Grinnell Land; the other apparently Z. spinatus Goodsir, previously known from the eastern coast of the Atlantie and from the Arctic ocean. IJdya furcata (Baird) was also occasionally found. It is a species of wide distribution, and has been rezorded from Rhode Island by Williams. A few examples of Parathalestris Jacksoni (Scott) Sars were also observed, a form not hitherto recorded from the Western Atlantic, a statement also true for Halithalestris Croni (Kroyer) a single example of which was taken, unmistakeable from its exceedingly long and divergent fureal rami.° Cirrhipedia. A few Cirrhipede larve were observed in one of the October collections and again on February 20, February 26, and March 2. On March 6, they were present 1W. Giesbrecht and O. Schmeil. Copepoda I. Gymnoplea. Das Tierreich, Lief. 6, 1898. 2G. O. Sars. An Account of the Crustacea of Norway. Vol. V. Bergen, 1911. 3R. R. Wright. The Plankton of Eastern Nova Scotia Waters. Contr. to Canadian Biol., 1902-5. Ottawa, 1907. 4L. W. Williams. Notes on the Marine Copepoda of Rhode Island. Amer Nat. xl, 1906. 5In the table all the Harpacticide have been grouped together under asingle heading, since with the exception of H. uwniremis they were of very occasional occurrence and then only in small numbers. ry 8 DEPARTMENT OF THE NAVAL SERVICE 2 7 GEORGE V, A. 1917 in considerable numbers in the surface plankton. and on March 20 they became very abundant, and continued to be so, with some occasional diminutions, until April 21. The appearance of these Balanus larve in large numbers was, accordingly, coincident with the vernal increase of the phyto-plankton, corresponding almost exactly with the increase of Biddulphia, Coscinodiscus and Fragilaria, and preceding slightly that of Thalassiosira. Malacostraca. ‘ Of the remaining groups of Crustacea, relatively few representatives were observed, and only at rare intervals. Two examples of the Schizopod Thysanoéssa inermis (Sars) Hansen were taken January 1, both belonging to the variety Rhoda of Hansen, who finds intermediate stages between the forms described as Rhoda inermis and Thysanoéssa neglecta and has united these into a single species with two varieties.t ‘ -Zoeas were also observed on various occasions, but their numbers were few, and no attempts were made to determine the species represented by them. PROTOCHORDATA. Tunicate larve and Appendicularians were observed, the former in considerable’ numbers, on November 11, and in the early part of January, the latter only rarely in October. The Appendicularians were not in a satisfactory condition for exact deter- mination, but apparently both Fritillaria and Oikoplewra were represented. PISCES. A few pelagic fish eggs were taken on two occasions, April 21 and May 13, but it was not possible to determine their source, since their preservation had rendered them almost opaque. A young fish, about 1 cm. in length was also taken on April 21 at the 3-fathom level.. It was a young example of Liparis liparis Linn. and had evidently been engaged in feeding upon plankton Copepods, one of which was- observed within its jaws. This fish, with its suctorial disk, is essentially a bottom form, its suctorial disk being an adaptation to that mode of life, and its capture in a plankton-net is there- fore a matter of some interest. Notr.—A further study of the plankton in the neighbourhood of St. Andrews during the past summer has revealed errors in the identification of two of the forms mentioned above. That which was doubtfully regarded as Rhizosolenia gracillima proves to be Thalassiothrix longissima Cleve and Grunow, while the forms identified as Hurytemora hirundoides were pro- bably merely immature examples of H. herdmani. This latter correction is based upon obser- vations kindly communicated by my friend, Dr. Arthur Willey. 1See H. J. Hansen. The Crustacea Euphausiacea of the United States National Museum. xlviii, 1915. i oo Si F fee a. 4 , * - ” Ya : oe 2 r ’ ~ = “ a J mes 7 SESSIONAL PAPER No. 38a . DEPARTMENT OF THE NAVAL SERVIOE f OE saa? & Prey, Ss TABLE distribution of the Plankton elements during the Winter of 1914-15, at St. Andrews, N. ~ 4=abundant; 3=frequent; 2=occasional; 1=rare. ae g 3) o alee : A : | Zz BR) Bla . ; ‘ 2/8 _ 2 Ss a : Cl 4 fe £ Salt Sissi Q J - 2 | * x - E Depth | Amt. | Temp. | Temp. d S)a| 2148 Eu -|2/8/¢ 2 3 Fs 8 |s= 2 Bia2 £523] -2 = 2S 4 & g : Date, Locality. S= in Air. | Water| Tide. | 2 |i] 6 | |S Ze 5 #/Sle.|2¢/85/ 3 /szl_. a | g|_siszesigs E Biles cite hata Raniarks 1914-15. Surface.| cb. ec. | Fahr. | Fahr. g|/£/s 2 2 3 z 3 a 33/3 les! s [Seis 8] 3/2). 8/3 3/8 S/3 5 3s gelaz 2) 2 #3) 3 |22 3 5 |E4 e S131 8] 183 @| 5/2) 3 22 2 |23] 2 |S S/25! & iS elSe/SESSleSle cle sles leciee] £28] =| 3 lee 8 |S) eaules ts #| 2/2/38 |55] § (2a) & soles! & So/SalesisclSaGaGoieclsulea! & |as| 5) Biles O}f/0]e ja Blalelolo |6 A /ale ls [ale ff Sia jf I ae le le jo | mulel aie et. 16..|Digdeguash Hr... 8 1 67° 52° | hr. ebb 2 | alee A eos 2 2, Mi i IMigdecuaen Hr 6m. 27-5 57° 52° | hr. ebb Meni e ae ZF 3]. ? ..|Sand Point... ae ae ag a 4 ebbe! a A eee r ..|Sand Point. m.- S° 5 ebb. . : eralium furca, Peridinium divergens, Dinophysi i : ii ie Nealg Doints s 13 48° 51° |14 hr. flood.| 2 |... 3 Nénthrs (Olserade clsnaG ee ao nophysis norvegica, rare; Nauplii abundant. .-|Joe's Point. -| 6m. 20 48° 51° {13 hr. flood.|.... 4 i * Mouth of St. Ei Dy 12 44° 48° |Lhr. ebb...} 1 3 |. Immature Copepoda abundant; Anthomedusa. .|Robbinstow Gm. | 3 Se Gs 3 a icules, Annelid setae; d . m. ° ..--|Sponge spicules, Annelid setae; dead hydroid stems abun q : 8 5 36° 46° 4]. ..|Immature Copepoda and nauplii Mantle hndene ‘ - ..|Mill Cove... 6m. 40 40° 42° 4 .|Immature Copepoda abundant. ..|Joe’s Point. 8s 16-5 40° 42° 4]. .-|Joe’s Point. 6m. 27-5 40° 42° 4 ..|Mill Cove. . 5 13 46° 42° 4 _.|West Light. rs) 42° 43° 4]. ..|West Light. 6m. 26-5 42° 43° 4- oc 2 -.|Navy I 8 9 42° 43° 4). .|Immature Copepoda and Nauplii abundant. ..|Navy 1 6m. 36 42° 43° 4 ey ..|8t. Andrew's Hi Ey} 77 26° 39° 4]. ..|Much amorphous material. ..|St. Andrew's H 6m. 25 26° 39° . oF : -|Biol. Station. 6m. 35 28° 38° bia | aime Des 4 ..|Immature Copepoda frequent. us ‘ oars 22° 36° |2hrs. ebb...) 1 : 3 |. .../Immature Copepoda and Nauplii; Sponge spicules. us 6m. 8-8 20° 36° |2 hrs. ebb...|....|. 3 4 :! 5S 10 38° 37° |}hr.tonigh) 1 |. T= 4]. 6m. 16 38° 872 Whr.to high! Tl) 2.). 555) Saet emtae eeiel|etetete | oe 3 |- 4 5 5-5 10° 36° |High.. | 3 pills 4 ie Ss 6m. 12 10° 36° |High.. wml Bale 4 .|Thysanoessa inermis. est Light Ss 55 30° 34° |thr.tohigh} 3 |. meter 4 .|West Ligh 6m. 9 30° 34° |} hr.tohigh} 1 |. 3 4 ae Ss 5-5 33° 34° |High 2 1 4 ..{Immature Copepoda abundant. 6m. 55 33° 34° ne 2 4]. fs) 22 33° 34 Mi Bega 4). 6m. | 42 nem ude | ie f aA s 12 40° 34° |h hr. 1 eedll 4]. Immature Copepoda, Crustacean exuviae abundant. 6m. 37-5 40° 34° |i hr. to high]... . 2]. 4]. Immature Copepoda abundant. S) 11 32° 33-5°| 4 hr. ebb..| 1 |. reel 3 |. 6m. 33 32° 33-5°| 3 hr. ebb..|.... 1 3 |. 8 16-5 37° 33° | 4hr.ebb..| 2 CaN F 6m. 31 37° SRP segs teleeal! al yeos ib 4]. 8 12 33° 33° |Lhr. ebb...| 4 u 4]. 2 6m. 27-5 33° 33° jl hr. ebb..s| 1 |... 4]. -|Biol. 58 9 36° 33° |lhr.ebb...} 2)|... Cra belived rec ft ¢ r 6m. 17-5 36° 33° jl hr.ebb...| 1] 11]. 4]. 5 8 27-5°| 33° |lhr.tohigh| 3] 4 3 Sponge spicules frequent. 6m. | 25 27-5°| 33° |Lhr.tohigh| 2| 3 4 Sponge (?) spicules frequent. .|Robbinstow: Sy | htanoard 38° 33° |thr.tohigh| 3] 2 |. 2 Sponge (?) spicules and Annelid setae frequent. Robbinstown. 6m. 14 38° 33° |S hr. tohigh| 1 it lle 4 Much miscellaneous “dirt.” | 2 ‘ A Joe’s Point.. 6m. 3 44° 37° |High.. APPEASE ke il Sand, sponge and annelid spicules, Nematodes, Rotifers, Rotalia, Gomphonema. .|St. Andrew's Hr... . Sy) 5-5 30° 33° "i 4| 2 1 Immature Copepoda and occasional sponge and annelid setae. St. Andrew's Hr.. 6m. 20 30° 33° LS ea ees Th |e 4 .|West Light... 5S 4-5 36° 33° |2hrs.tohigh| 2] 2]. 2 4 ut 2 6 m. 13 36° 33° |2hrs.tohigh| 3] 3 |. 3 |. 4 e $s 7-5 40° 33-5°|/2hrs.tohigh| 4] 4 |. 4]. 4 6m. 20 40° 33-5°/2hrs.tohigh| 3) 4 |. Al's 4 aL xe Pe 34° 4) 4 A . 4 m. 2 0" 34° 5 i 2 s 3 40° | 34° Blea 2 |. 4 Much “dirt.” ‘ etd 6m. 6-5 40° 34° ule oule 3 4 Annelid and sponge spicules, Bacillaria. as Ge ro 34° 4) 4 ab 4 m. ie 0 . ist 18-5 45° 35° ian Fi : 4 4]. Crustacean exuviae abundant. iS} 5-5 40° 36° 4 | 31) Bil 4 Mov ile Crustacean exuviae frequent. 6m. 13 fj 3 4 i , ) 3 rie ae Aan A fens i 2 Ri, eeae Crustacean exuviae frequent; Rotifers rare. 6 m. 31 B i if 3 5 75 Se 3° i 4 4 Pay Fi y Bale ieee .|Immature Copepoda.; Zoeas rare. 6m. 5 52° 38° 5 tee end] Shi Bosal 2! SHE 3 2 6m. 4-5 52° 40° |2}hrs.tolow| 2 |....]. 4 Dale 1 .|Plutei rare. Gs As ante 45° 39° |1hr.tohigh}| 1| 1 4 2 : b dl Conepod nauplii. ne 2 i e i . F $ A ee ae Deas Xu ee qi he ...|Nauplii and immature Copepoda rare; Rotifers rare, 6m. 16-5 50° 41° |2 hrs.to low.|....|- 4\. 2 .|Plutei rare. s 31 56 | 44 |} br. ebb... 4]. 1 : eepened| paauelit rare: 6m. ° 2 .|Rotife: : at 8 ai a a ar i is opp - i ; 3 ._|Anthomeduse and nauplii rare. 6m 16-5 | 48° 4 |t ebb... mal 4 ../Anthomeduse rare. 38a—1} Ce Ne ; . 7 wn —- BaF ence oe ae . he 7 GEORGE Vv SESSIONAL PAPER No. 38a A. 1917 : DIATOMS AND LOBSTER REARING. By Prof. W. T. MacCiement, M.A., D.Sc., Queen’s University, Kingston. - The entirely commendable desire to increase the annual crop of lobsters, and thus add to the income of the fishermen as well as to the supply of a delicious sea food, has prompted attempts at the semi-domestication of the lobster. A creature may be said to be domesticated when it will reach full size, will reproduce freely, and will live about the normal life-time of its kind, in the artificial conditions furnished by man. We are as yet far from reaching such a desirable state of affairs in our relations with the lobster. While mature female lobsters, captured in the sea, will extrude eggs freely in captivity, we have not yet, in the few experiments made, so closely approxi- mated to the conditions required for the health and growth of young lobsters, as to see before us in the near future the prospect of large and successful lobster gardens, maintained by the amphibious farmers of the Maritime Provinces. The account of the experiments inaugurated by the Biological Board of Canada will be found else- where.* With only one factor of the environment of the lobsters has the present writer had intimate relations, and it is with that this article deals. 1. Actions or Lorster Larv#. For several days after they are hatched, young lobsters show a desire to occupy water that is well lighted. They crowd to the lighted side of a glass vessel, and within a few seconds will have deserted the shaded for the sunny portion of the water in which they are lying. Otherwise they show little recognition of direction in their movements, sinking quietly or jerking themselves apparently aimlessly up or down or laterally through the water, often with their backs or heads downward, and with their bristly outer leg-branches constantly vibrating. Their spasmodic movements are probably the result of various stimuli besides that of light, as is shown by the fact that they seize greedily any small object that seems likely to make them a satis- factory meal. When the minute lobsters are crowded together, this edible object is quite likely to be another lobster of the same brood.’ The stronger of the two immediately shows how fond he is of his relative by eating as much as possible of kim or her. Cannibalism is one of the factors always to be kept in mind in connec- tion with artificial arrangements for rearing the lobster. Whether the lobster larve normally seek the lighted surface layers of the sea in which they are hatched is unknown, as few of them have been captured in open waters, and very little is known of the details of their lives when free. Surface layers may or may not be their natural haunts, but all attempts at rearing the young lobsters have been made in well-lighted and somewhat shallow enclosures. The idea is accepted by the experimenters that the young lobsters are attracted to the bright surface waters, that there they are visible to the perpetually hungry larger denizens of the ocean, such as the schools of herring and mackerel, and that consequently myriads of the lobster larve are devoured before they have learned even the alphabet of self- defence. After they have moulted a few times, four or five, they acquire the form and features, though minute, of the adult lobster, and show the adult habits of seeking concealment, and of using their claws as weapons of defence. Hence it is believed *See Professor Knight’s Report on Lobster Sanctuaries and Hatching Ponds. Canadian Biology, 1914-1915. Supp. 5th Ann. Rep. Dep. of Naval Service, 1916, pp. 41-54. 11 12 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 desirable to protect the lobster larve against each other, against hungry alien enemies, and against starvation, until they show at least some signs of knowing how to care for themselves. 2. DiatomMs on Losster LARVA. Well-lighted waters have many inhabitants, notably minute plants, and some of these show a tendency to attach themselves to the lobsterlings. This is especially true of certain forms of diatoms which normally grow attached to each other and to larger submerged plants. Mature lobsters confined in ponds and cars become the carriers of various animal and plant forms, which are not parasites but symbionts in the simplest degree, merely borne by the animal. The extent of the plant growth will naturally depend on the sunlight received by the lobster, copious growths of alge reaching to many inches in length developing on the antenne and other appen- dages, even on the eyes, when the animal has been confined for several months in shallow, muddy ponds. When such lobsters are removed to clean surroundings they gradually free themselves from all growths within their reach. Ordinarily the moulting process will completely remove all the effects of this symbiotic growth, but instances are known in which the rhizoids of the alge have penetrated the covering" of the lobster’s eyes, and moulting left the creature clean, but blind. The extent of the growth of diatoms on lobster larve is dependent on certain factors of which the three most important seem to be: (1) The amount of sunlight. received, (2) the extent of time between moults, and (3) the activity or inactivity of the lobsterlings. We have direct evidence of the truth of the first two of these, and indirect evidence of the third. During the summers of 1914 and 1915 Dr. A. P. Knight, for the Biological Board of Canada, has carried on rearing experiments at Long Beach, Digby county, Nova Scotia. The complete description of these experiments will be found in Dr. Knight’s reports for those years. The opportunity given the writer to study this interesting relationship between lobsters and diatoms was due to the kind invitation of Dr. Knight, who most generously placed all the resources of the station at my service. In both summers the lobster larve were loaded with a growth of diatoms which became 60 great as to cause the larve to sink to the bottom of the boxes in which they were confined. There they rolled about in the current caused by the movement of the stirring paddles, but were soon found to be dead. Their destruction was probably caused by exhaustion, and by starvation. The impeding masses of diatoms so clogged the mouth parts and the legs as to prevent the larve from securing food. Similar difficultiés were experienced by United States experimenters in lobster rearing at Wickford, Rhode Island, the diatom infesting the larve there being Licmo- phora tincta Grun. During the summer of 1914 the lobster larve in Dr. Knight’s care at Long Beach, Nova Scotia, were destroyed by Synedra investiens W. Sm., which normally grows on an alga, especially on Hctocarpus.. This formed almost the entire growth observable during that summer, the only other forms present being Cocconeis scutellum Ehr. and Lichmophora Lyngbyet (Kutz) Grun., and these were not plentiful. In 1915, however, it was the last-named species which took possession of the larvee and reproduced themselves so rapidly as to prove destructive. The following record will indicate the rate at which they became troublesome to the young lobsters. The figures represent only approximations, as in all probability some diatoms were in positions where they could not be seen. The lobster larve ' were carefully scrutinized under a microscope, and care taken to make the counts as accurate as possible. DIATOMS AND LOBSTER REARING 13 SESSIONAL PAPER No. 38a August 2. Lobster larve 2 hours old.. .. .. .... .. No diatoms. rs a ss s 24 @ Lemcth lee tockes Spring Salmon. A curve showing ratio of weight to length. 7 GEORGE V SESSIONAL PAPER No. 38a tes A. 1917 ON THE LIFE-HISTORY OF THE COHO. By C. McLean Fraser, Ph.D. Curator, Pacific Coast Biological Station, Departure Bay, B.C. (With Plates V, VI, and VII (7 figures), and figures (Graphs) 8, 9, 10, 11, 12, 18. The sockeye and the spring salmon, among the Pacific species, have received the monopoly of attention of investigators ever since the salmon trade became an important one on the Pacific coast, and naturally so, because these two species have been so important, commercially. In more recent years, on account of the scarcity of these at times, especially in certain localities, the other species have come more into prominence. The coho or silver salmon is now quite an important factor in the output of the canneries. In the cannery statements compiled for the Pacific Fisher- man Year Books it is shown that there has been a gradual though rapid increase in the coho pack in British Columbia until, for the year 1915, it amounted to 13 per cent of the whole output. It does not show as large a percentage for that year for the whole coast, but in 1912, when the sockeye pack was very low, it reached an amount over 10 per cent of the pack for the year. Besides those that are canned, an increasing number is being put in cold storage. As the importance of the coho is thus rapidly increasing it seemed worth while to take advantage of a situation somewhat favourable for learning something of the life-history of the species. Some work has already been done on the coho. It has been considered, along with other species, in papers on the Pacific salmon, in several papers by McMurrich und one by Gilbert. These deal largely with the age at maturity of the species. Some of the points touched on in these papers will be considered in connection with others that heretofore have not received special attention. The favourable conditions referred to are these: Coho spawn in a small creek that flows into the head of Departure bay, and in this creek, at all times of the year, the young coho may be seen. A locality for observation is thus very conveniently situated. After they have migrated, some of them must remain in the strait of Georgia throughout their lives in salt water, and possibly they all do, as they may be caught with hand lines throughout the greater part of the year. Various stages have been obtained from hand line fishermen in Departure bay. Through the kind- ness of Messrs. Broder, a large number of specimens of mature fish, a good repre- sentative lot for the strait, was examined at the cannery at Nanaimo. To compare with these, through the kindness of Manager Crawford, of the Neah Bay cannery, I was able to get a number from the open ocean. In the creek at Departure bay the mature coho appear about the middle of November. As the spawning beds are but a short distance up the stream, not more than a mile, they are soon reached, and the spawning is over by the end of the month. At the Cowichan Lake hatchery, where, until this season, the greatest number of ecohos in the province were hatched, the first eggs were taken about November 10, kut the spawning season lasts for a considerable time, as even after the first of February there are unspawned fish in the streams of the neighbourhood. The eggs hatch in three months, or slightly less, but the alevins remain buried in the coarse sand or fine gravel at some distance below the surface for some time. On March 7 not one could be seen in the creek, although the last year’s fry were 39 40 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 plentiful. On April 10 the alevins were plentiful, and by April 14 a few of them had the yolk all absorbed. They gradually work down stream and even into the brackish water. By May 6 many of them were near the mouth of the stream, but I have never seen any of them out in the bay, or anything to indicate that they ever get out into the bay during the first year. Relatively, those in the creek at any one time vary much in length. On April 14 a catch of alevins and fry varied from 30 to 39 mm. Of nineteen caught on June 29 there were the following lengths: 33, 36 (2), 37, 39, 41, 42 (2), 43 (3), 44 (2), 54, 58, 60 (2). On November 19 there was wariation from 49 to 61; on March 7, from 52 to 67, with a single very small one only 42 mm. Some of them migrate to the sea as early as March, at which time they are a year hatched, but others linger in the fresh water much longer. I have seen none later than June 29, but on that date two were caught, 76 and 60 mm., and cthers were seen in the creek. None of them, however, remain throughout the whole second year. Evidence that this is true elsewhere will be referred to later, when the age question is considered more at length. During the first months after migration the yearlings are seldom observed; they are too small to be retained in the meshes of the gill-nets, seines, or traps, and too small also to be attracted by the spoon that is used in catching larger fish. They grow very rapidly, and in October an occasional one is caught with the hook and line. They are now 10 to 12 inches long, each weighing 12 to 14 ounces. They do not appear in sufficient numbers to attract attention until the spring, when they are just over two years old. In the latter half of April, the schizopods become so plentiful near the surface of the water at certain times of the day that large areas become noticeably pink. As the cohos have a decided preference for small crusta- ceans, they appear in great numbers to gorge themselves on these schizopods. The erustaceans are almost at the surface, and the young coho may be seen in all directions, jumping out of the water. They take the spoon readily at this time but, apparently, not because they are hungry, as they may be taken with their stomachs much distended with the pink food made up of thousands of these individuals. Locally, at this time, they are called “ bluebacks,” but this term is used in so many different senses, as several common names are, that it is scarcely wise to mention the fact lest it give a wrong impression. At the same time, or somewhat later, the young herring are little larger than the schizopods, and they also provide excellent food material. Probably at no other time in the life of the coho is there such a superabundance of good food available, and in consequence the rate of growth is rather startling. Fish that weigh 14 to 24 pounds at the middle of April, will weigh 3 to 5 or even 54 pounds by the middle of June, i.e., doubling the weight in two months. The length, which was from 14 to 19 inches in April, now runs from 18 to 23 inches. From this time on an occasional fish is caught in the vicinity of Nanaimo, but the real season for mature coho does not start until on in September. In other parts of the province it starts earlier than this. At several points from Alert bay to Prince Rupert a good catch was made last year before the end of August. These mature fish, now two years and seven or eight months old, vary much in length and weight. In the length, a variation from 18 to 31 inches has been observed, and in weight from 3? to 164 pounds. They are now on the way to the streams to spawn, and their life-cycle is soon completed. As to the food of the coho, from the time that the yolk is absorbed until maturity, there seems to be a decided preference for an insect and crustacean diet. When this is not available, reliance has to be placed on fish. In the nearby creek, as soon as the alevins work their way out of the gravel of the spawning bed, they move away from it down stream. By the time the yolk is all absorbed they are well distributed throughout the length of the stream, and not too much crowded in any one place. In consequence there probably is a supply of insect larve for all. Beside the coho, the only fish in LIFE-HISTORY OF THE COHO 41 SESSIONAL PAPER No. 38a the creek is the cut-throat trout, with an occasional small sculpin or fresh-water bull- head. .The cut-throat of the same year is not hatched for some time after the coho appears, and those of the preceding year are large enough to look after themselves. The young fry, therefore, have no fish as small as themselves to attack, and hence insect larve, with a few fresh-water crustacea must supply the demand. It is possible that those earlier hatched may attack those later hatched and that both may attack the cut-throat fry when they come out, but by this time they must have attained greater size. It is possible, too, that the yearling coho attack the firy, and the cut-throat a year or more old may do so also, as all the Salmonide eat fish when other food is not avail- able, if not at other times. In this creek the cohos and the trout seem to live in har- mony, as both are commonly found in the same small group. : It is a fact that when large numbers of fry are put out in the creeks from the hatchery that the older ones may be seen devouring the younger ones, but in such cases thousands, sometimes hundreds of thousands, are put out in the one creek within com- paratively narrow limits so that before they become well distributed insect food must be at a premium. As the younger fry offer the only food for the older ones, very hun- gry by this time, they are devoured. If there are trout in the same stream they prop- ably assist in the operation. The statement that coho remain in the rivers for two or three years feeding on the trout is evidently absurd. In the first place, the coho does not live to be three years old, or at least there has been no evidence adduced that it does. In the second place, there is a similar lack of evidence that any of them remain in fresh water for two years. Furthermore, as the yearling coho is seldom more than 5 inches long when it migrates, and more often is considerably short of that, the injury done to the trout by it must be very much exaggerated. In reality the coho has a much stronger case against the trout, the steelhead, the cut-throat and dolly varden or char. These fish follow the coho to the spawning beds and devour so many of the eggs as soon as they are spawned that the possible number of coho fry is at once very much reduced. No matter how often the male coho turns to chase them, they follow him back, as soon as he turns, to gorge themselves once more. After the eggs are hatched the fry are attacked. and it is there that the dolly varden does the most damage. It is the general opinion of observers all the way from the Aleutian islands to California that the dolly varden does more harm to the salmon fry than any other agency, and many will go so far as to say that it does more harm than all the other agencies put together. Therefore, instead of protecting the dolly varden by a close season, it would ba very much better for the salmon fisheries if everything possible were done to reduce their numbers. The case against the other trout is not so strong, but as they remain in the fresh water for a much greater portion of their lives than the coho, the balance of destruction is prob- ably in their favour. The food of the coho in the sea has been indicated. Pelagic crustacea form the bulk of it. Schizopods predominate if the whole year is considered but, at certain times, larval barnacles and larval decapods form an important portion. Of the fish used, reference has been made to the small herring fry. The older fry and even the herring a year or more old are eaten later in the season. Apparently they have pre- ference over other fish. Salmon fry, sand launces and capelin are the only other fish that have to be observed. For a short period about October the 1st the capelin are taken in large numbers as they come inshore to spawn. The mature fish feed actively until they come to the mouth of the streams up which they go to spawn, or possibly until they enter these streams. Consequently, they must increase in weight almost until spawning time. The general rate of growth has been considered and some remarks made about the age of the coho. A more complete analysis of the relation of growth to age, depending on the examination. of seales, will now follow. The method of growth determination 42 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 used is the same as that used in a prior paper on the life history of the spring salmon. In general, the winter checks show up more plainly in this species than in the spring salmon, so that there is seldom any difficulty in making out their delimitation. The scale appears first as a small, flat, almost circular body, which becomes the nucleus of the growing scale. At that stage of the appearance of this nucleus the fry is from 31 to 34 mm. long (in all measurements in this paper the length does not include the caudal fin rays), with an average of 32-5 mm. It is this size about the end of May or early in June. The rings then begin to form. From ten to fourteen appear in the first set; these gradually get closer together, although they are not very far apart at first. The last two or three may be dim, broken, and generally indistinct. They indicate the first winter check. At the time these are formed the food supply is at its lowest ebb, so that very little growth is taking place. In March or early in April the food supply becomes more abundant and the distance between the rings increases, showing more rapid growth, somewhat similar to that near the nucleus. At migration a decided increase takes place abruptly, due to the better supply of food in the salt water. It may be that the fresh water band for the beginning of the second year is entirely absent as some of the yearlings pass down to the sea too early to show spring growth in fresh water. More commonly the band is present, vary- ing in width with the length of time before migration takes place. Chamberlain! has reported that, in Alaska, a greater number of coho pass to the sea as fry than as yearlings. The evidence available for this region indicates a con- dition far otherwise. Out of nearly 400 examined for the purpose.of this research, only three showed indication of going to the sea as fry. These three were among those obtained at Neah bay on October 26. During the remainder of the summer the rings are formed as usual for salmon growth in the sea. The winter check follows and then the growth during the third summer, with the rings getting somewhat closer late in the fall when the fish goes up the stream to spawn. The scales of the three that went to the salt water as fry have the first-year growth in the nature of a broad band of distant rings next to the nucleus, followed by a winter check, the whole width of the band being similar to that of the second year, Since the first year shows no fresh-water growth, the second does not either, and the third year is similar to that in other scales. Even in the largest fish obtained there was no indication that the third year had been completed. As no one has recorded a fourth year specimen, if there are any such, they must be rare. The analysis of the results of examining the scales of nearly 400 fish, of which 301 were in the third year, gives an admirable basis for comparing the rate of growth in the different years and in the different fish. As the fry is, on the average, 1-3 inch long when the nucleus is developed, that amount has been taken from the total length in inches in each case and the remainder divided as the scale is divided by the winter checks. Then 1-3 inch is added to the first year value to obtain the length at the end of the first year. In these scales, the growth of the fresh-water portion of the second year was calculated also. In the whole number of fish in the third year, the least growth at the end of the first year was 2-4 inches and the greatest 4-1, with an average of 3)3. (AIl of the yearlings caught in the stream in early spring came between these same extremes.) The frequency curve to represent this is a fairly regular one, showing the greatest number at a length of 3-2, although nearly as many at 3-4 and 3-6. The growth for the second year varies from 7-5 to 14-4, with an average of 11-1. The greatest number came at 10-7 and 11-6. Although the base of the curve is much more spread out than in the first-year curve, the regularity is much the same. The length at the end 1 Chamberlain, F. M. Observations on salmon and trout in Alaska. Bureau of Fisheries Document No. 627, 1907. LIFE-HISTORY OF THE COHO 43 SESSIONAL PAPER No. 38a of the second year varies from 11-1 to 18-1, with an average of 14-3. The highest point of the curve is reached with 13-5, but there are several others nearly as high. That, in general, the yearlings that have the best start tend to keep it up, is shown by the fact that the average of the length at the end of the first year, added to the average growth in the second year, gives exactly the length at the end of the second year. For the growth in the third year, only those caught after September 15 are considered. Since there is such rapid growth during the third summer, a fair com- parison could not be made of all those caught during the year. Apart from an abnormally small growth, 4-0, and an abnormally large one, 14-2, the growth for the portion of the third year varies from 6-1 to 13-5 inches, with an average of 9-7; 10-0 has the highest point on the curve, with 9-5 and 10-6 nearly approaching it. The total length at time of catching of these same third-year specimens varies from 18-0 to 31-0 inches, with an average of 24-0. The highest point on the curve is taken by 23-0, but 22-0 and 23-5 nearly equal it. As the frequency curve here is made from half-inch measurements while the others are in tenths, they are not exactly compar- able. Here again the average length is equal to the sum of the average growth in the three periods, 3-3 + 110 + 9-7 = 24-0, and the length at the end of the three years © is 3-3, 14-8, and 24-0, respectively. The fish that went to sea as fry were not sufficiently numerous to serve as a basis for definite conclusions. The measurements were as follows :— 1. At end of 1st year, 9°6; 2nd year, 16°4; 8rd year, 24°0 2. ee oe 11°0 “ 19°4 “ce 25°0 So “ec it 11°4 ““ 21°5 Ti 28°0 Average ‘“ se OST e 19°1 « 25°7 There is no very appreciable difference between the length of the males and the females. The averages are:— Males —At end of 1st year, 3°83; 2nd year, 14°5; 38rd year, 24°1 Females— ‘“ ss 33: ss 14°2 ss 24°0 There is more difference between the average lengths of those caught at Neah bay and those caught in the strait of Georgia. Strait of Georgia—At end of 1st year, 3°3; 2nd year, 14°1; 3rd year, 23°7 Neah Bay —- st ss 3°6 eS 15°5 Ce 25°6 If the difference was in the third year only, it might be accounted for partly by the fact that those from Neah bay were caught a little later in the year than the majority of those taken in the strait of Georgia, but the difference is relatively as great at the end of the second year, and is noticeable even at the end of the first year. It might be that since all of the Neah Bay specimens were from the same lot, that was an early spawned lot and they were able to keep up the initial advantage. To keep up the advantage it would be necessary to have the proper supply of food in any case and probably the food supply is better at the entrance to the strait of Fuca or somewhere in that vicinity than it is in the strait of Georgia. This is borne out in the comparison of weights, a matter which is taken up later. The length at the time of migration varied from 2-8 to 6-6 inches, with an average of 4-5. Out of the whole number only eight were over 6-0 inches, and only twenty-two were over 5-5. The greatest number were at 4-6. Various calculations were made to see if the fish were ultimately smaller on account of the longer time spent in the fresh water at the beginning of the second year, but no constant differ- ence could be found even in the growth for the second year. The time of hatching, and consequently the length at the end of the first year, seems to have more to do with the total growth and the second year’s growth than the length of time spent in the fresh water during the second year. Possibly if a greater number were examined, some difference might be shown. 44 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE \V, A. 1917 Going on the supposition that the fish that were first hatched during the season would, in general, have the greatest growth to the end of the first winter check, they were divided into three groups according to their lengths at that time. The first group included all those that were 3-0 inches or less at the end of the first winter check; the second included those that were over 3-0 inches and up to 3-5 inches; the third included those over 3-5 inches. The average growth in each case was as follows :— 1st group—At end of 2nd year, oer 0; when caught, ne 6 2nd “ “cc 4°1 Dole? 3rd “e sc “ee pe “e 5°0 The difference indicates that the fish that are the largest at the end of the first year, and hence probably those that were hatched out earliest, have an advantage that tends for greater growth throughout life. When the weight of the fish was compared with the length, it was found that there was a very definite ratio between length and weight. The youngest fish of which the weights were taken, or which enough weights were taken to make a com- parison possible, were those slightly over two years old, taken in April. From these the following table was obtained :-— NoOPOaADrO _ oO on oo _ In some cases there was but one specimen of the particular length, hence some irregularity is shown. This would probably be eliminated if there were several of that length from which to take an average. In comparing the weights of the mature fish, the males and females were taken separately, and those from Neah bay were separated from the others. In the table which follows there is some irregularity, as in the preceding table, due to the small number of specimens for certain lengths, more particularly towards the extremes of length, but even with these figures it is possible to see the definite relation between length and weight. There is very little difference between the weight of the male and the female for the same length. What difference there is, is in favour of the female. In comparing the Nanaimo fish with those from Neah bay, the latter have what little advantage there is. In both Nanaimo and Neah bay material, the males are at the head of the list for size, taking the whole size of the individial fish. LIFE-HISTORY OF THE COHO 45 SESSIONAL PAPER No. 38a WEIGHT. Length. NANAIMO. Neau Bay. Male. Female. Male. Female. In Lbs Lbs. Lbs Lbs SE aN rhe icteca le A Raia es ads sky ona scake choke aR, eee Ale See 3-75 3°75 Se heal Pa lees rail (ssh one, ele (NO gh Ak A ee ea ae PERS Serta MM NS rel: = Soars a aM ey cl ahs Sued acer 4 GIR cease rete te lle Rheem be Docs |b secre Mee Llanes Ge alist oat 4-625 4-75 5-5 4-875 RAEI ears tr arthiek ale 5-25 itr diy ballSe co aiiG see 5-5 5-75 6-5 5-75 5-875 ong! Teenie its 7-5 6-375 Gos 7Dillas pee 7:5 6-5 6-75 7-25 8-5 6-625 7: 7-5 8- 7: 7-25 8- 8-25 8- Sie Gs eet eee 10-25 8-25 8-375 9- 9-25 g- 9-25 9-5 10- NES Cheon les an eet Gg DCE nes Gl RIG Ae Dietetics etry Sorcha Cee nn) PA coe te aa ne 9-5 eects, Heelee 11-25 5 rh Sick ADIGA ELD Ry ke SoM A a et IB, Se mea 10: 11-5 11-5 9-75 11-5 11-5 11-75 oobi filedvers Socket 12- 12- Fe aR | cr oe a RPT Oe 12-75 15 ahs, Lael lps CANALES 13- 13- Si 7:0) haha | MRI sks oi [Rie cee eran GD) wan eteevea. fe on armlarck regis STS ANS 6 Pee ae acer RAR ee ce SUMMARY. The coho, which is mature in its third year, spends the entire first year, with but very few exceptions, in the Vancouver Island region, in the fresh water. Some of them migrate about the time the first year is completed, but others remain later, even until well on in the summer. There is no indication that any remain in fresh water to complete the second year. The scale shows a distinct winter check in the fresh water growth and another in the sea growth. The average length is 3-3 inches at the end of the first year, 14-3 inches at the end of the second year, and 24,-0 inches when caught in the fall of the third year. There is an indication that the fish that are largest at the end of the first year become the largest mature fish. Although some of the yearlings stay in the fresh water longer than others, it was not apparent that this made any special difference in the ultimate size of the fish. There is a definite ratio between length and weight. In the mature fish, the females weigh slightly more than the males of the same length. In connection with artificial propagation, as large a portion as possible for the season’s hatching should be procured from the early spawning fish that the fry may be larger at the end of the first year and consequently larger as mature fish. No species of Pacific salmon should get more benefit from rearing ponds than the coho, as almost the whole of the fry remain in the fresh water for a year in any case, and very few naturally get the benefit of accelerated growth in the salt water in the first year. From the standpoint of economy, the waste caused by early fishing can readily be appreciated when the great percentage increase in weight during the summer months of the third year is taken into account. 46 Fic. J DEPARTMENT OF THE NAVAL SERVICE EXPLANATION OF PLATES. PLATE’ V. . Coho scales in early stage of development. Scale from a coho in the fall of the second year. . Seale from a coho in the spring of the third year. PLATE VI. Scale of mature fiish in fall of third year. PrATE Vilb Scale of coho that migrated as fry. : Centre of previous scale more highly magnified. GRAPHS. . Frequency curve for first-year growth. second-year growth. third-year growth. length at the end of the second year. length of mature fish. amount of growth in fresh water. 7 GEORGE. V, A. 1917 . Centre of scale more highly magnified to show winter check in fresh water growth. PLATE Vv. Coho Salmon. PATE V1. Coho Salmon. PLATE vil Coho Salmon. STPRPTAT PUT jo “ON SIENPIN PUT JO ON 40 50 20 10 Fig. 8. Coho. 9.0 Fig. 9. Coho. 20 30 40 Length inInches Frequency curve for tirst-year growth. Length in inches Frequency curve for second-year giowth. SIEMpINNpUy Jp off STERN pratpuy jo ON” Length in Inches Fig. 10. Coho. Erequency curve for third-year growth. 38a—4 Fig. 11. Coho. Length inInches Frequency curve for length at the end of the second year. S[ENPIAIPUT jo "ON Length in inches Fig. 12. Coho. Frequency curve for length of mature fish. » i=] S[eRpIAIpuy jo ON — = 30 40 50 60 Length im Inches Fig. 138. Coho. Frequency curve for amount of growth in fresh water. 7 GEORGE V SESSIONAL PAPER No. 38a A. 1917 AN INVESTIGATION OF OYSTER PROPAGATION IN RICHMOND BAY, P.E.1., DURING 1915. BY JULIUS NELSON, PH.D., BIOLOGIST. New Jersey Agricultural Experiment Station. At the re-yuest of the Biological Board of Canada, the writer, during August, 1915, turned aside from his oyster studies in New Jersey waters to investigate the oyster situation in Richmond bay, Prince Edward Island. A study of a region so remote from a locality hitherto familiar, gave promise of furnishing data that would help in dis- tinguishing between local and “ essential” influences in oyster propagation. The ultimate object of these studies is the promotion of the oyster industry, both as a fishery and as oyster culture. It is an effort to conserve and to increase food resources, creditable alike in those who investigate, those who direct, and all who in any way encourage such researches. PART I—GENERAL PRINCIPLES OF OYSTER CONSERVATION AS APPLICABLE TO CANADA. The oyster-bearing waters of Eastern Canada are practically confined to those bays of the gulf of St. Lawrence that indent the coast of Prince Edward Island, and the adjacent shores to the south and west, viz., Cape Breton and the province of New Bruns- wick. Farther south, the coast is now practically barren of living oyster beds for a thousand miles, i.e., along southwestern Nova Scotia, the bay of Fundy, and the gulf of Maine practically in its entire extent to Cape Cod. That this coast was once prolific in oysters, though more sporadically than further south, is shown by the existence of oyster reefs recently fossilized, of ancient shell-heaps and by the traditions of colonial and more recent history. It is of both practical and theoretical interest to ask, “ What caused the extinction of these oyster beds?” On the true answer to this question hangs our conclusion as to the fate of the Canadian oyster industry. One of the older! answers to this question assigned the cause of extinction of oyster beds along these northern coasts, to the gradual rising (geologically) of the shores, thus finally bringing the oysters so near to the surface that they were killed by wintry frosts and ice. It may be surmised that, if this process continued, the utter extinction of the Canadian oyster beds might be the ultimate outcome. It appears, however, that the coast is actually sinking; but the oyster reefs have been growing upward somewhat faster having attained a thickness of over 20 feet and have reached as near to the surface as possible. If proximity to the surface limits the growth of an oyster bed, the sinking of the coast has tended to prolong the life of the bed. It is dif- ficult to see how either of these conditions can extinguish the life on an oyster bed, since a limit of height is ultimately attained, where there is a balance between recup- erative and destructive forces. Everywhere, the tendency of oyster beds is to grow as high as possible. In the south, the oyster reefs are exposed at low tide; the oysters can- not feed while uncovered, yet the oysters are not starved out. But if the coast should rise, the living surface of such reefs would be killed, while the oysters at the edges would gradually spread into deeper water. On the other hand, the sinking of the bottom would be highly favourable to oyster growth, provided that temperature and salinity conditions 1 Ingersoll’s Report on the Oyster Industry, 1882, Tenth Census of U. S., p. 25. 388a—-43 53 54 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 were not utterly transformed so as to pass beyond favourable limits. If the northern coast has been sinking, it is possible that this has perm’ tted cold arctic currents to enter some of the bays, or to influence the adjacent water that enters on the tides, so that the temperature necessary for summer propagation (68° F.) is not attained. The extensive shallow flats of Richmond bay and other noted oyster-producing bays of the gulf of St. Lawrence offer the conditions favourable to the warming of the water to the point needed for propagation. As regards salinity, we know that oysters flourish best when situated where there is a tidal increase and decrease in the salinity of the water; but oysters do grow in waters of very different degrees of saltness; and also in places where there is remark- able uniformity in density. While too much emphasis has been laid on this factor, yet it remains highly desirable that further study be made of the relation of salinity to oyster feeding; but temperature, oxygen, and currents are of much greater significance in oyster growth and propagation. A study of the temperature of the waters where oysters are now extinct would dis- cover the cause of their extinction. From the tables of temperature! determined by Professor Copeland for Passamaquoddy bay, it is evident that oysters can not propa- gate in those waters; but there is less evidence that oysters flourished there in early times than for some of the bays of Maine. Even in Prince Edward Island there are fossil oyster beds in the vicinity of living beds; thus we conclude that there must be also other causes for the extinction of oyster life. In respect to frost, it is remarkable to what extent oysters survive exposure to freezing, when partially imbedded in mud and thawed out gradually. It is asserted that where the water is so shallow that the ice rests on the bottom, at low tide, the oysters are killed by the pressure, unless they lie on a soft bottom, where, however, they are in danger of being buried. On the other hand, a heavy fall of snow before ice forms, clogs up shallow waters and kills oysters and even clams, according to the testi- mony of intelligent and experienced oyster planters. The effect of melting ice, and especially snow, upon animal life has yet to be studied in a scientific manner. We are confronted with two opposing influences. Shallow waters, especially when so free from grass as to be swept by currents, favour oyster propagation in the summer, but are most unfavourable to oyster life in winter. Just here is a situation that can be advantageously handled by the art of man, so as to greatly improve upon nature; for the young oysters produced on the flats can be moved to deeper water on the approach of winter. This is never done under the conditions of a free or public fishery. It is in the interest of conservation that oyster farming be introduced to supplement natural production. The foremost difficulty encountered in this con- nection is not our inexperience and our ignorance of the proper way to raise oysters, so much as the opposition of those who believe in harvesting what nature produces without contributing the labour of cultivation. It takes many years of education and the observation of the increased harvest resulting from oyster farming, as well as the annually decreasing product secured by free fishing, to teach the oyster fishermen that it is to their interest as well as that of the general public, to promote scientific oyster culture. Man has been the oyster’s greatest enemy; although, if he will use remedial measures, he can more than counteract the destruction. It is supposed that the disappearance in recent historic times of some of the natural oyster beds is due in large degree to the increased amount of sediment carried into bays by rivers, on which saw-mills have been erected, or whose drainage areas have been cleared and ploughed. Sawdust and sand are the most injurious of the forms of silt; light mud is more readily handled by the ciliary feeding apparatus of the oyster; yet when silt is present as a nearly continuous suspension in the tidal currents, it seriously 1 Contributions to Canadian Biology 1906-10, p. 286, ete. OYSTER PROPAGATION IN Le Dele 55 SESSIONAL PAPER No. 38a interferes with feeding, causing ultimate starvation. Silt that settles may be abun- dant enough to bury oysters; but even an exceedingly thin layer deposited on the objects used as cultch by the spat, will prevent fixation and therefore to the same degree prevent propagation. Assuming the spat to have secured fixation, it takes proportionately less silt to smother these delicate tiny oysters, than will bury the adults. The main cause of the destruction of natural oyster beds in historic times has been improper and careless fishing. The history of the oyster industry everywhere has shown that when oyster fishing has been pursued under no other regulations than those born of the wishes of the fishermen themselves, the natural beds were rapidly depleted, and finally exterminated, unless remedial measures were undertaken. Accord- ingly there have arisen many laws regulating this fishery, that seem strange to those engaged in private farming. For example, oysters may not be taken from natural beds except during the “open season.” The “close season,” during summer, varies greatly in its limits according to locality, but usually includes May, June, July, and August. Fishing must be confined to the hours between sunrise and sunset. Oysters may be taken with tongs but not with rakes; and dredges may not be used, nor may oysters be taken through the ice. Oysters may not be sold under three inches in length, and those smaller than this must be returned to the beds, etc. These laws are enforced by police methods; and fines and penalties are imposed for a breach of their provisions. Under private culture each farmer tries to promote his own ultimate best interests, and thus also the public welfare; but those who share in a public fishery consider only their own immediate self-interest. They sacrifice their own future, as well as the public welfare. The oyster laws are a result of an honest and fairly intelli- gent endeavour to conserve the natural oyster resources, and they undoubtedly partly succeed in effecting their object. It will be instructive to consider for a while the question of the depletion of natural beds and their conservation. AGENCIES DESTRUCTIVE TO OYSTERS. It is a fundamental biological principle that the agencies that destroy the indi- viduals of any living species nearly balance the natural rate of increase; that after a species has established itself in any locality the number of its population remains. nearly the same from year to year, though the balance between birth-rate and death- rate will fluctuate slightly up and down as one or the other set of factors increases or decreases. For instance, if food becomes temporarily more abundant, there is an increase in population, while a decrease in food results in a reduction of individuals, through starvation. So likewise there will be fluctuation due to the prevalence of various enemies and epidemics. Under this law there must be as many deaths as births; or, vice versa, the number of births must be sufficient to make good the loss by death. Therefore, we can judge of the extent of the destructive forces by simply noting the fecundity of a species. The oyster is one of the most prolific of all creatures. A single large ‘‘ spawner” has been estimated to produce annually sixty million eggs, but we must remember that half of the oysters are males, and that there are many small oysters. Neglect- ing the very small “seed” oysters, we may conservatively say that an oyster bed produces from ten to fifteen million young for each adult present; so that, if all lived and there were no further propagation, an oyster bed would be ten million times larger in five years. In spite of this astounding conclusion, however, the oyster beds are being depleted simply from the annual removal of a few hundreds or thousands of barrels. This should be the most convincing proof that the natural foes of oysters are extraordinarily formidable. Then why may we not believe that the destruction caused by man is insignificant in comparison, and so need not be considered to have 56 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 any practical effect? Because “it is the last straw that breaks the camel’s back,” and because all natural species, including oysters, exist under a balance. We have only to refer to the extinction of the American bison, which existed in such huge herds on our plains; or still better, the extinction of the wild pigeon, whose flocks in migration used to darken the skies of nearly a continent for days. It is absurd to believe that this species was hunted until the last pair was shot. The destruction by the hunter, great as it was in the case of the bison, or of the pigeon, was probably slight in comparison with all the other natural enemies, but the latter, suddenly sup- plemented by man, finally turned the balance, and completed the work after the hunt- ing ceased. Let us consider some of the destructive agencies operating against oysters. THE MEANING OF FECUNDITY. When the oyster ejects its millions of eggs into the water, these at first tend to sink to the bottom, which they would reach in ten minutes in calm water. In order that the eggs may develop, they must be fertilized by the male spawn or sperms. The sperms must be sufficiently abundant to enable an average of three hundred to cling to each egg during the ten minutes the egg is afloat. They must have been recently ejected from the male oyster or they will have died. The male oyster must have been ready to spawn at nearly the same time as the female, and must have lain sufficiently near, so that the water flowing over him shall reach the female by the time she emits her spawn. This is favoured by the fact that the process of spawning usually takes several hours or even days. We need to ascertain a good deal more than we know now before we can make precise statements, but we know that even where water is in such favourable agitation that the eggs are prevented from sinking to the bottom, they must be fertilized within a quarter of an hour to undergo normal development. This is the first reason for the enormous production of eggs. In spite of losses, vast numbers of developing young are started. As many as ten thousand newly hatched oyster fry or larve have been counted in a single bucketful of water dipped up over an oyster bed. But this signifies that there are other chances yet to be taken. COMPETITION WITH PLANKTON ENEMIES. After hatching, which occurs in from five to eight hours, the young oyster swims so weakly that the feeblest current carries it hither and thither. Indeed, all it effects by swimming, is to reach the surface and then to dive again, and so keep going up and down, requiring an hour to swim a distance of a few feet. But the oyster fry find the water is crowded with minute enemies, such as Copepods (water fleas), the “veligers ” if the many snails that cover the bottom, and a vast number of the larve of bivalves of various species, all capturing everything within reach small enough to enter their hungry maws. These enemies eat the young oysters, and the messmates consume their food. For several weeks the young oyster has to run this gauntlet and obtain sufficient food to effect an increase in volume of a hundredfold before it attains the spat stage in its development. Great as has been the ninefold decimation, yet so many survive that, if clean oyster shells be planted at the time of spatting, as many as a hundred or more spat may be caught upon a single shell almost anywhere upon or near an oyster bed. LOSS BY TIDES. This, great survival is the more remarkable when we reflect that twice daily a vast body of water runs over the oyster bed out to sea, carrying myriads of larve, and only a part of this water returns. The astonishing fecundity of the parent oysters suffi- ciently meets this loss also. But the struggle for life has not yet ended. OYSTER PROPAGATION IN P.E.I. 57 SESSIONAL PAPER No. 38a THE QUEST FOR CULTCH. Unless man has placed clean cultch in the water, nature provides only the old shells of dead oysters, mostly buried in mud, or the outsides of the living oysters. These and other exposed shells are more or less covered with slime, silt, and mossy growths of both animal and vegetable nature. Millions of other larve also needing cultch, such as “ deckers,” “ jingles,’ “barnacles,” etc., have pre-empted the best places and are busy feeding on every living thing they can swallow. Worst of all, through the open valves of the older oysters and of mussels, clams, etc., currents of water flow, bearing all sorts of plankton, presumably also oyster fry, to be used as food. How small a chance these fry have of escaping and finding a foothold! If they cannot fixate they are doomed to destruction. But vast numbers do find a foothold and do succeed in growing, and crowding each other, and competing with all the other oysters for food. In this struggle the survivors ultimately overgrow and smother the previous generations. Great as is the loss through crowding, it is exceeded by or anticipated by an earlier destruction, sometimes including all the spat on most of the shells. THE ENEMIES OF GROWING OYSTERS. The numerous little Nassa snails are constantly exploring the surfaces of shells and scraping off all the newly set spat. Those that escape may reach the size of a fingernail, and then, along comes a boring snail] and drills a hole through them, or a erab nips them off, or mud stirred up by storm smothers billions in a day, or the frosts of winter kill them. Later come the starfishes opening the oysters by their patient rrall, or bottom fishes may crush them in their paved jaws and throats. Last of all, man comes with tongs, and rakes, and dredges, and takes the few survivors. Thus ends this eventful history. The fisherman then wonders why the Creator doesn’t supply new oysters the next season to replace those taken: usually the best answer given to this question is to bow in meek submission to Providence. CONDITIONS FOR PROPAGATION. A little insight into oyster biology should enable any one to see that the production of oysters depends on the co-operation of four conditions, viz: (1) suitable cultch, (2) in waters stocked with a sufficient number of spawning oysters, (3) lying close enough to ensure fertilization of the eggs, (4) on a bed sufficiently extensive to fill the water, over a considerable area, with oyster plankton to such a degree as to over- balance the larval mortality. When the large oysters, which furnish the bulk of the spawn, are yearly removed, as well as the cultch to which they are attached (including the young oysters attached either to them or to the cultch), then the bed is robbed in three-fold degree, viz., the cultch is decreased, the large spawners become fewer, and the “rising generations ” are many times decimated. If the production of spawn is reduced to half, and the available cultch to half, then the production is reduced to a quarter. When shells, hitherto buried, are uncovered by working on a bed, they become available as cultch, but this advantage is greatly reduced through the fact that much silt is scattered upon the shells by the very operation which exposed them. In oyster fishing, ultimately all the cultch utilized by spat will have been removed, and then we have remaining simply an oyster reef covered by a layer of mud, upon which not an oyster can be produced. even though a current rich in oyster plankton, derived else- where, should flow over it at a time when the fry are matured to the sessile stage. Clam production is much simpler, for no cultch is needed. 58 DEPARTMENT OF THE NAVAL SERVICE ; 7 GEORGE V, A. 1917 STEPS IN CONSERVATION. One of the earliest steps taken in most instances towards the conservation of natural oyster beds has been the enactment of a “cull law.” This compels the fisher- man to sort his catch on the bed, throwing back the unmarketable material, consisting of shells and small oysters. The main advantage secured is the conservation of a per- centage of the seed oysters. The spat attached to the large oysters cannot be removed, while the shells which are returned are largely silted up when spatting time comes. In fact, these shells, unless newly dug out of the mud, require to weather for weeks, exposed to rain, snow, sun, and air before they are suitable for spat collecting. It is evident that no fisherman would thus care for the shells, unless compelled by law; yet it seems to the writer that it would be a practically enforceable provision, were it embodied in the cull law, particularly if a market for these shells could be secured. Sometimes the State has purchased cultch and placed it on natural beds; but this prac- tice was abandoned for two reasons: the cost of the work was greater than under private enterprise; and the Government felt it was making a gift to a special class. Where oyster farming prevails, the planters would buy this cultch, particularly in those regions, where shells are scarce because no shucking operations are carried on. Now that oyster culture is under way in Canada, the securing of cultch is a matter of great concern. It appears that the most available supply must come from a sorting of the so-called “mussel-mud” dug out of dead oyster reefs. The firmest of these shells, which are often of large size, when washed clean, are good collectors. But no cultch should be planted until spatting has just begun. Happily, scientific oyster research has in recent years enabled us to closely determine this date; but important matters are still to be cleared up. THE RATE OF PRODUCTION OF A BED. The legal restrictions imposed on the fishermen have the object of conserving the natural oyster production. The cull law helps this in a measure. Another prominent legal provision is the “ close season” during summer, when no oysters are permitted to be taken, because it is believed that the spawning oysters should not be disturbed, nor the cultch be littered with silt by fishing operations. This “ close season” has been lengthened from time to time, at both ends, by shortening the “ open season,” in order to reduce the number of oysters taken, it being believed that the bed is unable to supply oysters in quantity equal to the demand. It is doubtful if this provision becomes effective unless made so drastic as to practically deprive the fisherman of his means of living. When these enactments fail, more drastic measures are advocated, such as the closing of the oyster beds for a number of yéars, until nature has had time to restore them. But such legislation is founded on a failure to grasp a fundamental principle,. to wit, a depleted oyster bed will be restored at a rate dependerit on the percentage of available cultch multiplied into the available spat. Assuming that there are still enough oysters remaining to produce a fair abundance of spat, and that there are plantings of cultch on the bed at the proper times, then it will take five years for the bed to reach its acme. Then if this bed were henceforth left undisturbed by man, the forces of destruction and of natural production would just balance. On the other hand, suppose there was no planting of cultch, then, under nature, a depleted bed would take an indefinitely longer time to reach its original condition. In any event, after such a bed has reached the point of highest production, a survey of its extent and examination of an average square yard or rod, will enable one to calculate just how many bushels of oysters are present. Knowing then the number of bushels that can be taken in the open season, it can easily be reckoned how many years will elapse before the bed again will be reduced to a point where the fishermen can not secure their average catch. It should be evident that under artificial culture the OYSTER PROPAGATION IN P.E.I. 59 SESSIONAL PAPER No. 38a ranks of the oysters are restored by fresh cultch, under whatever rate the adults are removed, so long as the remaining oysters furnish sufficient spat. In case a 5 year- old oyster is marketed, then, without culture, if so large a proportion as a fifth of the product on the bed be taken each year, nature would not be able to replace this com- pletely, for reasons already explained. Yet the demand on the restored bed might be so great that half of the oysters would be removed onee year, two-thirds of the remainder the next, plus any natural increase, and so on. Thus the old story of gradual depletion would be repeated. For the first two years after a bed is opened, the production would be double or treble what it was before the bed was closed, but it soon drops back to the small figures. Now, calculating that there is no harvesting tor the five years during which the bed has been closed, and suppose that in five years it must be closed again, we see that in the course of ten years the average yearly pro- duct is equal to the minimum harvest. There is no gain in production, and the only advantage is the saving of the oyster bed—a bed greatly depleted and not yielding its full capacity. The fact is, that a natural bed yields the highest food production when all the oysters above a certain size are removed annually, and an equivalent ot ceultch is added. But such a bed gives the highest possible yield of oysters if it is used solely as a propagating bed, the seed being sold to oyster planters to mature for market on ground that could not be used for propagation. This is an important matter, and we need to go into it from the point of view of scientific oyster culture. EFFICIENT Use oF OysteR GROUND. Suitable localities for propagation and growth may in general be occupied by (1) natural beds, (2). under artificial oyster culture a certain additional area used for propagation and growth, and (3) an additional area for growth only, and (4) in a still further area, oysters might live for a while without growth. Area No. 4 is useful for storage only; Nos. 1 and 2 are so nearly alike, biologically, that fishermen have contended, sometimes successfully, that they are alike legally, so that farmers who had made such areas productive, were robbed of the fruits of their labour. When we realize that area No. 2 would be barren but for the labour of man, we must justly conclude that from a legal point of view they are radically different from natural beds, however much they may resemble them biologically. Assuming that a farmer owns only areas like No. 3, then he cannot produce his ewn oyster seed, and must secure it in various degrees of development, from either the fishermen who harvest No. 1 or from farmers who own areas No. 2. His problem becomes this: Which ventures bring the best returns, the purchase and cultivation of oyster seed requiring one, or two, or three, or four years, to mature for market? Tf there is a law preventing the fishermen from removing oysters under marketable size from natural beds, then the farmer of No. 3 is dependent on what he can secure from the cultivators of No. 2. Let us next consider the culture of ground No. 2. ‘As this is suitable for propa- gation, the owner can catch his own seed and is thus independent of the public beds. His ground is also suitable for growth, and so his problem is to find out which pays better, either to keep the seed on the ground where caught, until it is marketable, or to sell it at the age of one, two, or three, or four years, to owners of No. 3. In the former case, his farm will resemble a public bed, biologically speaking, but he can handle the situation to his own best interests, with his best judgment, and not under the restrictions pertaining to public fishing. He will remove each year the right number of marketable oysters, replacing them at the proper time by fresh cultch. He may do better: he may divide his ground into five plots—a, b, c, d, e. Let a represent the plot that catches the best set of spat. Each year, for four years, he will remove all the spat from a and plant them successively upon ), c, d, e, respec- tively, reshelling a at the proper times. He gets no pecuniary returns until the fifth 60 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE \V, A. 1917 year, when he markets the entire crop on b. In case there has been annual spatting on this ground, he culls off the immature oysters and places them, not on c but on the plots where oysters of similar ages are found. Thus ¢ is cleared to receive the next crop that is raised on a. From thence on, he has an annual income, harvesting one of his plots yearly and replanting from his seed;raising ground. We have gone into this detail with a purpose. This method of farming is the highest form of specialization, and should give the highest possible returns. Now please note well: each year the farmer harvests only one-fifth of his farm, and one- fifth of his growing crops. If he kept the entire farm like a natural bed, taking off an annual crop from the whole area, it is evident he could not do so well because all the generations would be intermixed and competing on those parts where there was most propagation, and on other parts less favourably situated, the propagation would not be at the maximum rate, but at a rate that would greatly reduce the annual pro- duct of marketable'oysters. At the very best, he could not harvest as much as a fifth of his crop, and he would have to use better methods than those now in use on the natural beds, to keep his oyster bed from depletion. Oyster farming resembles truck gardening in some respects, but differs in need- ing several years to mature the crop. On a mixed bed, the best returns come from removing annually as many oysters as can be spared, and not by introducing a system of open and close seasons. It is evident that what is good treatment for a mixed bed under private ownership, will be best for a similar bed under public ownership. There ean be but one conclusion here, viz., that if natural beds are to be conserved, they should be under the supervision of an expert, and should receive plantings of cultch at the proper times. The expert must determine just how many oysters may be annu- ally removed. THE FATE OF DEPLETED BEDS. Under a system of private oyster culture, it is necessary for planters who have little or no propagating ground to obtain their seed from natural beds. This leads to an abrogation of the prohibitions against taking immature oysters. Then the fishermen will market their catch at home, for planting in waters more or less adja- cent to the public beds. The inevitable result will be to render the latter as barren as possible. When both cultch and oysters are gone, the bed is extinguished. But in this ease, if cultch be placed on the bed it is as productive as ever, up to the limit of the supply of cultch. This is due to the fact that the oysters which have been removed are still growing and spawning in neighbouring waters, so that a supply of spat is brought to the old grounds. The fishermen will harvest this -rop of spat, and sell to the planter, or plant it themselves on their own farms; and history shows they will as zealously guard rights to such beds as they formerly did where they were con- fined to harvesting mature oysters only. As no one puts cultch on such beds, it is plain that however much spat may be present in the water derived from the private grounds, the beds will last only as long as the cultch naturally present will last, and that the production will be only as much as the available percentage of cultch present. Inevitably such beds become “barren” bottoms and open to leasing. There can be only one way of escape, and that is for the fishermen to form a co-operative society _ to work the public beds under a mutual agreement. But this, of course, cannot be done, because others of the public than the fisher- men, are also owners. Fishermen have been offered first chance in taking out leases of what they considered to be public ground, and have refused because they know that if once this right is granted, all or nearly all of the public grounds will ultimately come into the ownership of capitalists. So here we have a special phase of the old struggle between capital and labour. It is not our purpose to more than touch on the skirts of the matter that is political rather than biological, but still is vitally involved in any scheme of oyster conservation. OYSTER PROPAGATION IN P.E.I. 61 » SESSIONAL PAPER No. 38a THE LEGAL SIDE. Experience has shown but one successful way of developing oyster resources, and ‘that is the encouragement of oyster farming. The introduction of oyster culture has always met with opposition from the public fishermen, and such opposition has had a degree of justification. Usually it has been so mingled with prejudice and short- sightedness, that the sympathy of the general public has been estranged. Theoretically, the best interests of the whole public require that the oyster industry should be conducted wholly by methods that have proved successful in private farming—letting private judgment manage business operations, rather than a code of regulations. Practically, however, the best course to follow is to recognize the existence of public beds, and public fishing rights. Such rights and beds should be carefully defined, and the boundaries of public beds marked in a clear and simple manner, even though some barren bottoms should be included. Only by extreme or radical measures can natural oyster beds be preserved. But where oyster culture is successful there is less necessity for conserving such beds. The public oystermen have endured a sur- prising amount of restrictive legislation, supposed to be as much for their interest as that of the public. Under our larger view of the oyster question, the fishermen might be given more freedom and influence in shaping the regulations for the use of the public beds. Restrictions should primarily have in view the protection and encouragement of oyster culture, in which the real public interests inheres. Efforts should be made to secure impartial justice for all. A mutual obligation rests on both fishermen and farmers, to respect each others’ rights. Those who wish to frame the wisest laws, seeking for harmonious co-operation between these conflicting interests, are advised to study the history of oyster legislation in as many states and countries as possible. There will be found a variety in details, resting on local conditions, and a similarity in general principles, resting on biological grounds. THE DECLINE IN THE CANADIAN OYSTER PRODUCTION. That oyster production in Canada, and particularly in Prince Edward Island, has steadily been decreasing is evident from statistics. See “Table showing the aggregate quantities of oysters caught in the Dominion since 1876, compiled from annual reports of the Department of Fisheries,” given on page 47 in the report of the Dominion Shellfish Fishery Commission, 1912-18. In this table we note a curious back-and-forth fluctuation from year to year; but if the entire series of years be divided into five-year periods, and the annual product be averaged for each five-year period, or semidecade, the annual catch in barrels is as follows :— Prince Proportion Periods. Years. New Nova Edward for P.E.I. Brunswick. Scotia. Island. |Per cent of whole. (CL) Remar diategetnaterts care ates tah ES ees 1876-1880 9,724 1,172 17,020 60 (CAMS Aatne cock - SE BAME ES th oRicnak Eire 1881-1885 12,765 1,652 34,644 70 Ci eat Refem. seteh A aaa ea ee aameeene 1886-1890 20,426 2,049 36,379 60 Ea eo tener et Rae Siete tere ee, 1891-1895 17,434 3,027 30,622 60 (epee ameter ves ictats Shinn © eee op yspatalte ee 1896-1900 18,740 2,150 22,735 50 (GYR SE ree ans Ce eta Be. Oh pte 1901-1905 12,854 1,517 19,860 60 UD RRR Pas erat se) okra dla Hk uae Leia a enn (oa aa 1906-1910 16,564 1,597 10,583* 30 SOLE ESIC aA GRO nc HAGLER CERO RID aa iene 1911-1912 15,436 2,090 8,835 35 *For 1907-8, the quantity credited to Prince Edward Island was only 1,672 barrels. Leaving that year out, the average for the remaining four years becomes 12,811 barrels, which is 40 per cent of the average total credited to the Dominion for the same period. 62 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 The third period shows a maximum of oyster production in the Dominion, and also in the two main oyster-producing provinces. The decline began in the middle of the fourth period, mainly in Prince Edward Island, which led in production up to 1906, when it sank to the level of New Brunswek. Thenceforth it fell behind until its pro- duction reached only half of the province of New Brunswick. The decline in the latter province from the maximum has been little more than 20 per cent with 80 per cent decline in the island province. This difference in the rate of depletion has been explained as due to two main influences: the greater demand for the island product - and the discovery of new beds in New Brunswick, when several of the older beds were fished out. It is interesting to read the summary of the reports of various inspectors and experts from 1868 onward, given in Ernest Kemp’s “ The Oyster Fisheries of Canada,” 1899. These reports sound a uniform warning that the Canadian oyster industry was in danger of complete destruction unless proper measures were taken to conserve it. The decline in the industry has not been so keenly realized by the fishermen, because the price of oysters has increased proportionately. This fact augurs seriously for this industry. Oysters, even when cheap, are considered somewhat of a luxury, and a rise in price must tend to exclude them more and more from the menus of the middle classes; while at the same time the importation of foreign oysters must increase. The Canadian fisherman has relied for the protection of his interests on the superior quality of his oysters; but this superiority is threatened in two ways: first, it has become neces- sary to market oysters from beds that do not produce them of the highest quality; and second, by the attempt of planters to grow imported seed in Canadian waters, in the hope that they will attain the citizenship at least, or, if possible, attain the quality of the home product. This “American” seed is sometimes of inferior quality and, although it certainly improves under cultivation in more southern waters, it les dor- mant for a long time, without growth, when transplanted to the northern beds. Accord- ing to the claims of the fishermen, with whose product these oysters compete, when sold, it injures their market by giving the oysters from their locality a bad reputation. The cultivation of foreign oysters in Canadian waters is of considerable scientific as well as practical interest. From the shght evidence at hand, we conclude it will take more than a year to acclimate Connecticut seed in Canada, before growth begins. It will take a correspondingly longer time to impress the Canadian quality upon these oysters after growth begins. It will, therefore, be wise to import this seed as young as possible to secure the best results. It is still somewhat doubtful whether the Canadian oyster may not be a distinct variety, breeding true to its kind. The Canadian oyster spat, at the time of fixation to cultch, is a fourth larger than the spat in the corre- sponding stage of development in New Jersey waters. Whether this difference is due to environment or is inherent, remains to be settled by experimental observations, Oysters usually show improved quality in colder waters, due largely to the shortness of the spawning season. While it is interesting to note the outcome of attempts to cul- tivate “ American” oysters in Canada, it will be wisest for the Canadian planter to do all he can to promote the production of the native seed. ; PART IL—OYSTER PROPAGATION SURVEY OF RICHMOND BAY, P.EJI. In presenting the following synopsis of observations made in Richmond bay we wish to call attention to the fact that there are many points in the life and habits of oysters and their young that are yet unknown and which should be known in order to make the proper applications to economic problems. Aiming to make our investi- gations throw light upon these other matters, at the same time that we attempt to be as practical as possible, the work of surveying so extensive an area as that of Richmond bay by the methods developed by our previous experience, introduces much complexity. There were so many things that should receive simultaneous attention that much was OYSTER PROPAGATION IN P.P.I. 63 SESSIONAL PAPER No. 38a crowded out or missed, which demands a more specialized investigation. Lacking previous familiarity with this considerable expanse of water, it seemed best to get as broad a view as possible of the conditions, from which departure could be made in any special direction, as the findings might suggest. DESCRIPTION OF METHODS. The most important procedure is the determination of the oyster “ plankton,” i.e, the young “fry” in the water, which furnishes the “setting” of “spat.” This study was prosecuted by the use of a net made from the finest bolting silk. Counting out Sundays and stormy days, plankton studies were made on eighteen days, at an average rate of fifteen per day and a maximum of more tlian twice that figure. The net gathers a vast number of many kinds of larve-—bivalves, univalves, water fleas, ete., and as it is necessary to sort the oyster larvee out from each sample, under a microscope, and count and measure them, the work is nervously strenuous and time- consuming. Our procedure consisted in straining approximately known quantities of water through the plankton net, and then to “wash” the “catches” into a series of wide- mouthed bottles containing sufficient formalin to kill the larve, so that they would all settle to the bottom. After a number of such samples were. collected, the boat was run into the nearest quiet harbour, where the sediment in the bottles was examined in partial lots, until the entire amount in each bottle had been sorted by the methods developed in our previous researches. The samples were collected in the following ways :— (1) Dipping water in the net while the boat was under full headway, the average rate was two samples per mile, each of 20 quarts of water. (2) Dragging the net back and forth by hand a definite distance and number of times while the boat was stopped. This is called “swinging” the net. (3) Towing a definite length of time, say a minute under reduced speed. (4) By means of a cylinder, devised with valves for this purpose, into which the net was fitted, we secured samples at definite depths, or determined the vertical distribution of the fry by lifting the net through a fixed distance, a definite number of times. We thus endeavoured to make our determinations quantitative as well as quali- tative in character. The point from which we set out each morning, and to which we returned each evening was Malpeque wharf. We were farthest from home each day at noon, and samples were taken as opportunity offered on the return route as well. We are desirous at this point of the narrative to express our thanks and hearty appreciation for the kindly courtesies extended by Prof. A. D. Robertson, the use of whose boats and other equipment we shared, doubtless at times at a sacrifice of his convenience, at least, he being engaged in studying oyster growth. LOCALITIES EXAMINED. For purposes of location and orientation, the following descripton of Richmond bay is given: This bay is a considerable southward indentation from the gulf of St. Lawrence, of the north shore of Prince Edward Island. The coast at this point trends northwest, thus the western shore of the bay is one and a half times longer than its eastern. A sandbar 10 miles long separates the bay from the gulf, and limits its outlet to a channel a mile wide situated at the northern terminus (cape Aylesbury) of the eastern shore. Each shore has three considerable indentations. On the east, most northerly is Darnley basin, next comes Shipyard basin, and at the head of the bay is Chichester cove. On the west, situated correspondingly are Bideford river, Grand river, and Bentinck cove. 64 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 Confining one’s attention to the channel or deeper parts of the bay, the tide enter- ing north of cape Aylesbury sends a small branch southward into Darnley basin. The main portion flows west at the southern end of the bar between Royalty point and “Fish” island. Three miles west from Aylesbury the tide strikes Horseshoe shoals and spreads thence in three directions: (1) northwestward for 4 miles to enter the mouth of Bideford river, between Hog island and Bird island on the east and Gilles point on the west; (2) the southwestward tide flows 2 miles to “Ram” island shoals where it bends south and southeast around Ram island on a 6 mile course into “ March water,” and eastward into Shipyard basin, to Malpeque wharf; (3) the central portion of the tide on Horseshoe shoals continues westward for 34 miles to North Bunbury shoals. Part of it continues on for 5 miles farther, passing north of Charles point to reach Grand river. The main portion of the tide, 3 miles wide, turns south between Charles point and Bunbury island. Four miles to the south it runs between Beech point on the east and Bentinck point on the west, and enters the head of the bay, where it ends in three divisions, viz., Bentinck cove on the west, Chichester cove on the east, and Webber cove, with Barbara Weit river on the south, 8 miles from North Bun- bury shoals. Apart from its estuaries, Richmond bay may be conveniently divided into: (1) an outer section or Lower bay, lying east of a line drawn from Ram island northward to Hog island, but this line should curve westward far enough at its middle, to include all of Horseshoe shoals; (2) an inner section or “ Upper bay,” lying south of a line drawn due west from Beech point to the cliffs north of Bentinck point; (3) a middle section, between the other two, that we may designate as the “ Central portion.” The southern half of this section is split into two by Curtain Islands shoals, which extend nearly 4 miles northwestward from Beech point. Bunbury island, situated near the northern extremity of these shoals, marks closely the geographical centre of the bay. We shall confine the term “Central bay” to the portion north of Bunbury. The part west of the shoals, from its shape may be called the “ quadrangle,” that to the east is “ March water.” The Upper bay empties mainly into the “ quadrangle,” but some water flows over the shoals into March water, which in turn also partly spills over Ram Island shoals into the Lower bay. The “Central bay ” receives the Bideford from the north, Grand river from the west, the quadrangle from the south, and March water from the southeast, between Bunbury and Ram islands. We shall consider successively the data secured from a study of the different localities. Most attention was given Grand river and March water; the data from other localities are fragmentary. BIDEFORD RIVER. This river from the head of navigation to Gilles point is 6 miles long. ‘Trout river enters it in the south, and a strait called the narrows, lying between Lennox island and the mainland, enters from the north. The lower part of the river is bounded on the northeast by Lennox and Bird islands, and it empties into the Central bay in con- junction with the waters of a large shallow lagoon that lies east of Lennox and Bird islands and west of the sandbar. The southern end of this lagoon is bounded by Hog island, near which are oyster beds that owe their existence to the influence of the adjacent flats, in warming the ebb tides. At the northern end “Of the widest part of the Narrows, on August 6, a few oyster fry were found in 20 quarts of water of 1,021 density, 70° F., the largest being ge microns! in diameter. At head of navigation in Trout river, August 17, during rain, high water was 1015 at 72° F. Vertical sampling of different parts of the river yielded oyster fry of 160 microns to 400 microns, at the rate of one per 15 to 60 feet. 1 Twenty-five thousand microns equal one inch. Oyster fry are first seen at 60 microns and “set” as spat when they are from 320 to 400 microns in diameter. OYSTER PROPAGATION IN P.E.I. 65 SESSIONAL PAPER No. 38a At the head of Upper Bideford, August 6, low water was 1019-5 at 74° F. Four samplings, each of 20 quarts, along its course to Trout river, yielded seven fry of 160 microns, and a few at 100. Between Trout river and the Narrows, August 6, in water of 1019.5 at 72° F., large fry were present at the rate of one per 30 quarts. August 17, fry were fourid of sizes 120, 180 to 260, 360 to 380 microns, at the rate of one per 60 feet vertical, which means that in water 30 feet deep, ten hauls from bottom to top would yield five large fry. In the section off south end of Lennox island, August 6, water was 1020 at 70° F., and only one large fry and a few small ones appeared. On August 17, 1019 at 70° F., three samples gave twelve fry from 160 to 400 microns, most being 240 microns. In the section along Bird island, August 6, only few fry present, and less than 120 microns in size. On August 17, water sample 1020 at 70° F., gave one fry of 200 microns. Central bay, adjacent to Bideford river, August 6, 1021 at 70° F., fry less than 110 microns. August 17, near low point, one fry 180 microns, one 240 microns. GRAND RIVER. From the bridge to the ferry is a distance of 4 miles, and from the ferry to Charles point is 3 miles. The latter section, 2 miles wide, is more a cove than a river. From the bridge to Southwest creek is nearly a mile, thence to Cross creek nearly two, and thence to the ferry is a mile and a half. About half a mile below the ferry at Black point the river empties into its cove. Section below the bridge, August 6, flow, 1018 at 72 F.; August 14, ebb, 1018-5 at 74° F. Vertical samples gave one fry per 20 feet, sizes 120, 160, 320, 360 microns nearly equally abundant. August 20, flow, successively 1018 at 66 F. and 68 4°, 1017 at 67 F., and farthest from bridge 1019 at 68 F.; very little hut sand in four samples. Samples on higher water gave one per 40 feet vertical, one per 10 quarts, four per minute towing, 80 to 200 microns. August 25, strong ebb, one fry per 6 feet of towing, from 120 to 320 microns, majority 240 microns. Towing one minute with large No. 12 net, gave seventy fry, 160 to 340 microns, with maxima at 240 and 320 microns; small fry escape through this net. Section below Southwest creek, August 14, 1019-5 at 71° F., fry one per 2 feet vertical; farther down, one per 6 feet, ranging from 200 microns to smaller, most are below 160 mu.! Half of oysters dredged are still filled with spawn. August 20, 1018.5 at 68 F., early flood, few fry; but when near high, 1019-5 at 68 F., fry are abundant, one per 6 feet vertical, one per 5 quarts, thirty per minute towing, ranging from 70 mu to 280 mu, mostly below 100 mu. Farther down, 1019-5 at 68 F., one fry per 6 feet vertical, one per ten quarts, twelve per minute, 90 to 860 mu. August 21, twelve samples, 1018-5 at 70 F., near high, gave one to 40 quarts, up to nearly one per quart, from 9 to 166 per minute, from one in 4 feet vertical, up to one per foot. Sizes run from 80 to 320 mu with four-fifths of them below 110 mu, and some at 200, 240, and 320 mu. August 25, half ebb, 1020 at 70 F., twenty quarts dipped, give from 9 to 33 _ fry, also at low 1019 at 74 F., got one fry per 2 feet vertical, and 34 per 160 feet of towing; sizes, 80 to 320 mu, majority below 120 mu, several at 180, 240, and 280 mu. August 28, 1019-5 at 68 F. flow; one fry in 8 to 15 feet vertical, eleven in 1 minute’s tow; sizes, 90 to 380 mu, with groups at 100, 150, 280, 320, 360 mu. Section above Cross creek, August 14, 1018-5 at 72 F. Oysters dredged here have all spawned, fry abundant, one per 2 feet vertical, ranging from 100 to 200 mu, and a few at 360 mu. Majority are 160 mu, perhaps ten days old. August 20, water low flow, 1018 at 68° F., few fry until near high, 1019 at 70° F. when fry are one per 40 feet vertical, one per 5 quarts and fifteen per minute towing, and of sizes 80 to 280 1 The name of the Greek symbol for ‘‘ microns,” is “ mu.” 66 DEPARTMENT OF THE NAVAL SERVICE 7 GEORGE V, A. 1917 mu, with groups at 100, 180, 240 mu. August 21, fry nearly fifty per minute, eight per 20 quarts, three per 10 feet vertical; sizes 80 to 320 mu, most are below 100 mu, a group at 180, a few at 240. August 25, low ebb, nine to sixty fry per minute towing, five samples, thirty to forty in 20 quarts; sizes 80 to 380 mu, the majority are below 120 mu: groups at 140, 180. 200, 240, 280, and 320. August 28, fry are one per 4.5 feet vertical, of sizes 90 to 340 mu, majority at 140. Section below Cross creek, August 6, a few small fry present. August 14, 1020 at 70° F., largest fry 120 mu. August 20, high, 1019-5 at 67° F., fry 80 mu to 320. Half ebb, 1020 at 70° F., fry at rate of one per 4 feet vertical, one per 5 quarts, and two per minute of towing; sizes are 80 mu to 220. August 21, fry were found at rate of two to six per 20 quarts, below 200 mu in size. August 28. fry at rate of three to nine per minute and one to 25 feet vertical, sizes are below 260 mu, mostly below 160 mn. Section near ferry, August 14, 1020 at 69° F., fry at rate of one per 12 feet vertical, under 200 mu. August 20, 1019 at 66°- F., few fry: at lower tide, 1019-5 at 62° F.. fry at rate of one per 4 feet vertical, and one per 7 quarts, grouped at 100 mu, 200, and 230 to 280 mu. Grand River Cove: The roughness of water here prevented frequent observat'on. August 20, 1019-5 at 67° F., in middle of cove, no fry. At cape Malpeque (Charles point) 1020-5 at 67°-5 F., fry at rate of one per 10 feet vertical, mostly small, one 200 mu. Avgust 21, 1019-5 at 70° F., three fry per 20 quarts, largest 160 mu. UPPER BAY. With the upper bay, extending 7 miles southeast of Charles point, or south from Bunbury island, we shall include: (1) the ‘“ quadrangle” 4 miles north to south and 3 miles east and west, whose corners are designated, respectively, by Charles point, Bun- bury island, Beech point, and Bentinck point; (2) a southern “head,” 4 miles north and south, 5 miles east and west, which receives seven tributaries, that will be reviewed in circuit beginning on the northeast. Oyster Creek: August 7, 1018-5 at 74° F. Thirty quarts inside the grass area at its mouth, yielded four large (160 mu) and many smaller fry. Outside the grass, the fry were few and small, and snail larve numerous. August 13, 1020 at 72° F., vertical sampling yielded a few small and one “large” (unequal umbos) fry in three hauls of 7 feet each. Chichester Cove and Indian River: August 7, 1019 at 73° F., in cove, and 1016 at 74° F., in the mouth of river. Snails numerous, oyster fry few and small, one “large”! found. Barbara Weit River and Cove: August 7, 1018-5 at 72° F. Many snails, few oyster fry. August 13, 1018-5 at 74° F., samples yielded two large and a few small fry. Nearly all adult oysters have spawned, but some not. Webber Creek Cove, or Waites Cove: August 7, many snails, few fry. August 13, ten hauls in 9 feet of water yielded two large, four medium, several small fry. August 24, twenty hauls of 5 feet each in 12 feet of water, yielded 33 fry, from 160 to 380 mu in diameter, at ratio of one per 3 feet vertical, and quite satisfactory. Shells were put out as cultch here. Plat River Cove: August 7, sample was poor in plankton, 1020 at 72° F., in grass near cliff west of Webber point. Oyster fry more abundant towards Bentinck cove. August 13, ten hauls vertical in 12 feet of water yielded five medium fry. Shemody Creek and Bentinck Cove: August 7, in creek, 1015 at 74° F., few oyster fry here. In cove, 1020 at 72° F., oyster fry more abundant. August 13, in mouth of creek, 1020 at 70° F., sample shows but one large fry. In the cove, 1021 at 69°-5 F., vertical sample in 5 feet of water yielded three large and three medium. Farther out, in 10 feet of water, vertical sampling yielded a larva of 240 mu. 1 We use the general designation of “large” for fry with unequal umbos, “medium” for those with prominent equal umbos, and “small” for those less than 100 mu in length. OYSTER PROPAGATION IN P.#.I. 67 SESSIONAL PAPER No. 38a “Head” of Upper Bay: August 7, sample near Bentinck point was poor in fry. In the middle of the bay the water was 1020 at 74° F. Each of two samples contained a fry nearly ready to “set.” August 24, on high water, 1020 at 68° F., a long course, dipping from Beech pert towards Webbers point, yielded but few fry, the largest ° was 240 mu. The quadrangle west of Curtain Shoals: August 7, in its southern portion three samples showed many snails but no oyster fry. Farther north it was much the same story, only one large fry found in four samples, but many snails. Commentary on Upper Bay: The considerable distance of this part of Richmond bay from our base at Malpeque, combined with the roughness of the “ quadrangle,” ‘prevented as full a study of this part as was desirable. Once we buffeted the waves quite to Bentinck cove and were compelled to return to shelter east of Curtain shoals. This sort of work cannot be done on a boat pitching extremely. From the data secured, it is indicated that the oyster plankton of the open bay is sparse, and that it is only close to the broad flats that line the shores, where the oyster plankton was fairly abundant. There seems to be some correspondence between water temperature and oyster plankton, more being found in the warmer waters than the colder ones. Another point to be noticed is that the water on the shore flats, probably never leaves the upper bay on the ebb tide, but retires temporarily to the edge of the flats to return on high water, and so the contained oyster plankton is not lost from this cause. This is on the supposition that the fry do not themselves have habits that would oppose their transport outwards on ebb tides. While this question is still under investigation there is strong evidence to show that fry are more abundant at the surface on flow than on ebb. Another interesting point concerns the snail larve. These were extraordinarily abundant in the Upper bay. The flats of the Upper bay are extensively covered with grass. We found snails more abundant near grass plots in all parts of Richmond bay. We do not know whether the snails feed on the oyster fry, but have suspicions. This matter is worth investigating. We know that snails are enemies of the young spat. It is probable that these snails should be fought in the interest of oyster culture. MARCH WATER. This part of the bay is bounded on the southwest by Curtain islands and Beech point. Across the shoals between the point and the islands, there is current com- munication with the “ quadrangle” and with the Upper bay. March water is bounded on the northeast by Prince point and “ Ram” island. Across these shoals, there is water communication with the Lower bay. But the main outlet is to the northwest, between Bunbury and Ram island, into the Central bay. The eastern part of the March water section is the Shipyard basin, at whose head is Malpeque wharf. Ship- yard river enters here from the south. Shipyard basin is separated from March water by a considerable grass flat. Extensive grass flats also cover the Curtain Island shoals. The oyster beds are mainly near Prince point, Ram island, north of Bunbury shoals, and the channel between Bunbury and Ram island. Owing to the fact that our home base was at Malpeque, and also that we had to traverse March water every “ime a visit was made to any other part of the bay, and that it was less disturbed by winds than other parts, this section received more continuous attention than the rest of the bay. It did not, however, offer so rich a plankton as did Grand river between Southwest creek and Cross creek. We shall consider our observation of it as a whole, chronologically. August 5, at low ebb, on “old dump” in northern part of Shipyard basin, 1020 at 70° F.