Kitwanga Lake J

Home , Baynes Sound

These Progress reports are issued from time to time to acquaint the fishing industry with some aspects of investigations undertaken by the Fish· eries Research Board of Canada through its Pacific Coast Stations.

CONTENTS

PROGRESS REPORTS NO. 68

Oil a~d Vitamin A Contents of the Liv.ers of British Columbia Flatfish Betty H. McKercher 43 Lemon Sole Spawning Grounds in Baynes Sound F. H. C. Taylor 48 First Year Returns of Lemon Sole Tags used off the West Coast of Vancouver Island J. I. Manzer 51 Control of Rancidity in Stored Fish, III H. L.A. Tarr 52 Lakes of the Skeena River Drainage. III. Kitwanga Lake J. A. McConnell and J. R. Brett 55 News Items 60 OIL AND VITAMIN A CONTENTS OF THE LIVERS OF . BRITISH COLUMBIA FLATFISH

Since the discovery of vitamins· A and D in fish liver oils, it has been a desire of investigators of the Fisheries Research Board to find new and potent sources of these vitamins, sources which would be available in quantities useful commercially. Halibut, lingcod, black cod and red cod livers and the viscera from several of these fish were successively utilized on the Pacific coast for theil."1 vitamin,s. During World War II demands for vitamin A increased greatly. The dogfish liver proved to be one of the most valuable sources of vitamin A, but' the supply even from this source is limited. It was thought that, because large numbers of flatfish were being caught in British Columbia for .shipment overseas, an investigation into the oil and vitamin A contents of the livers of the various! species might prove profitable. A preliminary study of flatfish livers was made in 1944, incidental to an investigation of the otter trawl fishery by Dr. J. L.1 Hart of the Biological Station at Nanaimo. The results, reported in Pacific Progress Reports No. 61, pp. 6-7, were considered suggestive enough to warrant a further study of the subject. Consequently, during the year April, 1945, to April, 1946, monthly samples of livers were taken from as many as possible of the seventeen available species, with the exception of the halibut, the value of which is already known. These samples were collected by members of the staff of the Nanaimo Station and of the B.C. Packers Ltd. They were brought fresh. or shipped in cold storage to the Vancouver Station, where analyses for oil and vitamin A contents were carried out. Altogether, 150 samples were obtained. Tabulations were made giving pertinent data such as place caught, number of fish in sample, weight of fish, weight of livers, and oil and vitamin A contents of the livers. The complete data, of which the following is a summary, may be obtained by writing to this Station. The liver samples were taken mainly from Vancouver landings of flatfish, but a few were shipped from Prince Rupert and from Victoria. During the course of the investigation, samples from fifteen of the seventeen species of British Columbia flatfish were examined, although samples of each species could not be obtained each month. None was received of the speckled sand dab (Citharichthys stigmaeus). The samples, therefore, varied q.s to species, season, and location, and the results, consequently, may be considered representative of the livers of the flatfish taken in British Columbia. Each sample, consisting when possible of one hundred livers of a species, was ground to a liquid pulp in a Waring Blendor. Duplicate samples were removed while this pulp was in motion. The oil was extracted from each portion by shaking it several times with peroxide-free ethyl ether arid anhydrous sodium sulphate. After the ether was largely removed by evaporation, the oil was vacuum-dried and weighed to give the percentage of oil in the liver.. Vitamin A determinations were made with antimony trich.loride reagent using an Evelyn photoelectric colorimeter. Numerous samples were taken from the three· species, brill (Eopsetta jordani), rock sole (Lepidopsetta bilineata), and lemon sole (Parophrys vetultts),

43 which together make up most of the commercial catch. These are compared in the accompanying graph. The number of samples represented in each month's average and the average proportion of liver in the fish are shown in table I. All three showed a somewhat similar seasonal variation in oil content of the livers, but the rock sole was highest in August, the; lemon sole in October, and the brill in December. The lowest values were obtained in January, April 1945, and May, respectively. The first two were comparable in oil content, highest values being 13.7% and 16.5%, respectively, and lowest values 2.5% and 4.3%. The brill livers were much more oily, ranging from 26.8% to 9.0%.

TABLE 1.-Data on brill, lemon sole and rock sole liver samples. Date Brill Lemon Sole Rock Sole No.of Av. liver content No. of ·Av. liver content No.of Av. liver content samples of fish(%) samples of fish(%) samples of fish (%) Apr.1945 3 1.03 7 1.13 4 1.00 May 3 1.56 4 1.19 3 0.93 June 5 1.62 4 1.39 5 1.54 July 3 1.97 4 2.05 2 1.55 Aug. 3 2.44 1 1.74 1 1.26 Sept. 3 1.95 4 1.58 Oct. 4 2.32 Nov. 2 1.93 2 1.91 2 1.69 Dec. 3 1.88 3 1.66 2 l.88 Jan. 1946 1 1.36 2 0.59 1 Apr. 2 1.17 2 1.33 2 l.08

The variations in vitamin A potency of the oils were in a general way in inverse relationship to the amount of oil in the liver, the potency being lowest in the winter months in all three species. This was reflected by the values for the vitamin A potencies of the livers. Such calculations take into consideration both the amount' of oil in the liver and the vitamin potency of that oil. The graphs show that the brill liver .is highest of these three species in both oil and vitamin A content. Samples from the remaining species were less numerous than from those described above. Consequently, any conclusions drawn from the results are indefinite and cannot be set down as rules governing those species. In all species, the potency of the oil was usually lowest in the winter months. Generally, but not always, the oil content was high in winter and low in summer. Some species gave results worthy of special comment. Sand dab (Citharichthys sordidus) livers contained a much higher percent age of oil than did the livers of any other species. The potency of this oil, however, was very low, the highest recorded being 4,050 USP. units per gram of oil from samples taken in May. Sinc.e the percentages of oil in these samples of livers averaged 36.5%, the total vitamin A per pound of 1iver was fairly high-640,000 USP units. The other samples of sand dab· livers were taken in April and June of 1945 and in January, 1946. They gave oil yields of 55.8%, 46.0%, and 59.6%, respectively, with vitamin A contents of the oils 1600, 2300, and 1200 USP units• per gram. Since the livers of sand dabs make up a larger proportion of the fish (2.9-4.4%) than do the livers of other species, it might be worth"'.'hile to utilize them.

44 ,...... ; ...... to OIL CONTENT

; I -::1

\ \ \ \ 100 \ ·-·-·-·- BRILL 2 \ .. ----- LEMON SOLE i; \ .. \ ------ROCK SOLE ~80 \ \ \ \ \ VITAMIN A POTENCY \ OF OILS. .;... iii ·,·,··· ...,_ "..~•o " '·, ·, \ to __ .... -•------..~ "'· ..... :- ~...... ·...... -----·---·~·---" -·-- ·------·-----. __:.....;;~~

VITAMIN A POTENCY \ OF LIVERS .. \ "0 ::; ~ ...... ;...··-·- ·-·,, =·2 ..... '· iii ' -,., " _1-·- ::;• I " '· i ·'-..... i I

.... .,.. •-...... --.... _.... _ .,- ~·'· ·- _...... '· ,/·"" t---·--·--.---·--- ·..::i.~ APR. N!v JU~E .-uiv · A~a. .J~-T.--HJv. -D1;.---g;--· ,i.. ..~ ... APfl. 1941 1141

Seasonal changes in oil and vitamin A contents of brill, lemon sole and rock sole livers.

45 Highest vitamin A potencies of the oil of the livers of these less frequently sampled species were found in the long-jaw flounder (Atheresthes stomias) and in the flat-head sole (Hippoglossoides elassodon). However, only one sample of the former was taken, in August 1945. It yielded 21.0% of oil with a potency of 22,150 USP units per gram. The livers (2.1 % of the fish) had a total vitamin A content of 2,112,000 USP units per pound. The results of analyses of the flat-head sole livers were rather erratic. The April 1945 samples (1.3% of the weight of the fish) gave an oil yield of 17.1 % with a vitamin A potency of 30,500 USP units per gram of oil. However, the livers taken in April of 1946 (2.27% of the weight of the fish) contained approximately the same proportion of oil (14.5%) but with a potency of only 4300 USP units per gram. To be ofl use in forecasting the seasonal value of livers, the results of one year should approximately duplicate those of previous years. Ranges of averages of liver yields from the fish, and of per cent. oil artd vitamin A contents of the livers of other species are tabulated in table II, with the month of each sample in brackets.

TABLE 11.-Data on the liver oils of B.C. flatfish. I Vitamin A Range .... GJ Species o-"' Liver wt. range, Oil range, ~i % of fish % of liver USP units. /g. oil USP units/lb. liver - Starry flounder 9 1.02 (Ap. 1945) - 5.7 (Ap. 1946) - 2,100 (Oct.) - 87,800 (Dec.) - (Platichthys 2.37 (Nov.) 17.1 (July) 22,400 (July) 1,739,000 (July) stellatus) Dover sole 8 0.53 (Jan.) - 4.4 (May) - 2,250 (Dec.) - 225,000 (Sept.) - (Microstomus 1.76 (Oct.) 22.4 (Dec.) 16,400 (May) 658,000 (Aug.) pacificus) Sand sole 7 1.10 (Ap. 1945) - 5.8 (Aug.)- 2,700 (Dec.) - 207,000 (Dec.) - (Psettichthys me- 3.89 (Dec.) 16.9 (Dec.) 22,300 (May) 714,000 (May) lanostictus) Rex sole 6 0.65 (Ap. 1945) - 5.8 (Ap. 1946) - 1,400 (Oct.) - 149,000 (Oct.) - ( Glyptocephalus 1.48 (Oct.) 23.8 (Dec.) 11,650 (Apr. 1946) 621,500 (Jan.) zachirus) Curl-fin sole 4 1.55 (June) - 3.8 (June) - 6,250 (May) - 153,000 (May) - (Pleuronichthys 2.36 (Ap. 1945) 10.9 (Ap. 1945) 13,500 (June) 450,000 (Ap. 1945) decurrens) Bu.tter sole 5 1.20 (Sept.) - 8.2 (July) - 7,600 (Sept.) - 240,000 (Jan.) - (Isopsetta 1.39 (Jan.) 15,7 (Sept.) 11,200 (July) 542,000 (Sept.) isolepis) C-10 sole 3 1.03 (Nov,) - 10.0 (Ap. 1945) - 8,950 (Nov.) - 443,500 (Ap. 1945) ( Pleuronichthys 1.48 (Ap. 1945) 15.5 (Nov.) 9,750 (Ap. 1945) - 633,900 (Nov.) coenosus) Slender sole · 1 3.05 13.4 12,350 751,300 (Lyopsetta exilis) (Sept.) Yellow-fin sole 1 2.34 12.4 850 47,900 (Limanda aspera) (Jan.)

The fish examined in this study were caught at. various locations scattered over the entire coast of..British Columbia. From a preliminary examination of the results it seemed that location made very little difference to either, the oil <::ontent o.f the liver or the vitamin A potency of that oil. The data in table I and the graph are therefore averages of all samples

46 taken in a given month. The greatest differences in the oil and its con tained vitamin A are apparently caused by variations in species and season. The size (age) of the fish is probably another factor. It was not considered in this study. The most valuable livers appear to be those of the .brill, but livers of all species produce vitamin A-containing oil. This comprehensive survey was undertaken on the suggestion of British Columbia Packers Ltd. and it was through them that the help of Mr. P. A. Sunderland in sampling was made available. Dr. J. L. Hart, Mr. F. H. C. Taylor and Mr. J. I. Manzer of the Pacific Biological Station helped material ly by providin,g samples also. Grateful acknowledgment is made to The Canadian Fishing Company, through whose cold storage facilities livers ·were shipped from Prince Rupert. Miss Joan Vernon and Miss Eileen Taylor provided .technical assistance during the analyses. Dr. L. A. Swain of the Vancouver Station conducted the analyses of the April 1946 samples. To these and to all others who in any ·way contributed time and effort to this experiment, I extend my sincere appreciation. Pacific .Fisheries Experimental Station Betty H. McKercher

Visit of Prof. Prefontaine to Pacific Stations

Professor Georges Prefontaine, Head of the Institute of Biology, Uni versity of Montreal, and member of the Executive Committee of the Fisheries Research Board, returned the latter part of August from a summer's survey in the Pribiloff islands where he inspected the fur seal work being done by officers of the U.S. Fish & Wildlife Service. While here he visited· the Nanaimo and Vancouver Stations in order to acquaint himself more intimate ly with the research projects being conducted. · He spent several days on the Skeena river looking over the operations on the lower river, at Lakelse lake, at Moricetown falls and at Babine lake and river.

Dominion Day Honours

Members of the Fisheries Research Board of Canada and staff . were delighted to find in His Majesty the King's Dominion Day Honours List that the following had received. recognition: . D.r. A. T. Cameron, Chairman of the . Board, C.M.G.; Dr. A. . W. H. Needler., O.B.E.; Lt.-Col. .H. B. Hachey, O.B.E.; Mr. 0. C. Young, M.B.E.; Mr. J. P. Tully, M.B.E. . . . . 47 LEMON SOLE SPAWNING GROUNDS IN BA YNES SOUND

The fishery for lemon soles in the Strait of Georgia is one of its more important winter fisheries and the Baynes sound area has been the most productive part of the strait. For example, in January and February of 1946 spawning fish captured there were responsible for about fifty per cent. of the catch. Because of its importance at thi~ time, lemon sole spawning was studied off Cape Lazo and in Baynes sound during January and February of 1946. The part of the work dealing with the roes of the fish showed the areas of the general region in which spawning was most active. This Progress Report gives the reasons for believing that most spawning took place in the two areas designated as Cape Lazo and Fanny bay. The evidence was collected in eight trips to this region in which fish caught in each of five areas were examined for spawning co~dition. When possible, forty fish were examined from each area on each trip. The spawn ing conditions for each fish were observed and were rated in six numbered groups with the following .brief definitions: I Immature; II Maturing; III Ripening; IV Ripe; V Running; VI Spent. Males were recognized only in groups I, II, and V 4 The observations are shown in table I below in which the numbers of fish in each condition are shown for each trip and area. Where no entry appears for a trip, insufficient fish were available for pre cise examination of spawning condition. It will be observed in the table that:- ( 1) Ripe and running females were taken in all areas. (2) Giving consideration to the fact that the Union bay February 24 sample, in contrast to the others, was taken on the edge of the Fanny bay area, ripe and running females can be said to be least abundant in Comox and Union bays and most abundant at Cape Lazo and Fanny bay. Deep bay was intermediate. From a comparison of samples taken at Cape Lazo, Fanny bay, and Deep bay on comparable dates, it can be shown mathematic ally, that the proportions of females falling into the spawning-condition classes depend upon the area-the chances1 being less than one in a hundred that this is not so. The greater numbers. of ripe and running females at Cape Lazo and Fanny bay cause much of this difference. (3) The yield of fish per hour of dragging was greatest at Ca12e Lazo, a little less in Deep and Fanny bays, and least in Comox and Union bays. ( 4) The proportions of spent females are highest at Comox bay and at Deep bay. At the latter place the excess is great enough to be significant. The conclusion is that, though some spawning takes place throughout the whole region, it tends to be concentrated in the areas off Cape Lazo and Fanny bay. This is shown both by the greater number of ripe and running females, and by the greater yields of fish per hour's dragging, taken in these areas. The high proportion of spent females in the areas at either end of Baynes sound, namely Deep and Comox bays, indicates that fish captured there are moving off the spawning grounds.

48 TABLE I.-Yield for fishing effort, and spawning conditions of lemon soles in Baynes sound area.

Spawning Condition-Female Spawning Condition ~0 ..d~ loJl I Male Area Date .,,.. "'G> .....= = ll.~. I II III IV v VI Total I II v Total ll..<.i:"Cl5i ~I Deep Jan 4 200 9 5 20 0 1 1 36 1 0 2 3 bay Jan 12 100 10 5 14 0 0 0 29 1 3 7 11 Jan 18 150 11 6 15 1 2 2 37 0 2 2 4 Jan 24 200 11 1 16 2 1 2 33 1 1 5 7 Jan 28 100 6 1 20 2 0 5 34 0 0 6 6 _Feb 13 50 37 1 5 2 1 4 50 0 0 0 0 Feb 23 - 15 0 8 0 1 18 42 1 0 7 8 Mar 15/16 30 18 0 3 2 1 44 68 4 0 21 25 Fanny Jan 4 150 9 1 13 4 2 1 30 1 0 13 14 bay Jan 12 100 5 2 12 2 1 1 23 0 0 17 17 Jan 18 200 4 5 23 4 2 0 38 0 0 2 2 Jan 24 125 12 2 7 5 4 0 30 0 3 7. 10 Jan 28 100 4 0 14 6 6 1 31 0 1 8 9 Feb 13 - 18 2 14 4 5 8 51 0 0 3 3 Union Jan 12 20 2 1 5 0 2 0 10 1 0 1 2 bay Jan 18 - 7 0 2 4 2 0 15 0 1 3 4 Feb 24 - 4 0 2 9 12 3 30 1 0 19 20 Comox Jan 5 100 8 1 3 1 0 1 14 6 0 0 6 bay Jan 12 60 13 6 17 0 0 3 39 0 0 1 1 Mar 17 85 14 1 0 0 0 39 54 2 0 2 4 Cape Jan 5 100 1 4 2 0 1 0 8 0 3 31 34 Lazo Jan 19 300 0 0 6 5 7 0 18 0 2 20 22 Jan 25 125 0 0 5 7 3 1 16 0 4 19 23 Jan 29 150 1 0 3 5 10 1 20 0 0 20 20

Tags put out during January support the belief that Fanny bay is the main spawning area in Baynes sound. It seems fair to say that most of these fish would be moving toward spawning areas. In table II, the recov eries whose exact points of recapture are considered reliable are shown. The areas of tagging are listed vertically and areas of recovery horizontally.

TABLE 11.-Tags recovered in each! fishing area from each tagging locality.

AREA OF AREA OF RECOVERY Cl) ,TAGGING Deep bay Fanny bay Union bay Comox bay Cape Lazo Deep bay 17 22 1 2 0 Fanny bay 6 16 1 0 2 Union bay 0 2 1 1 0 Comox bay 4 8 2 2 2 Cape Lazo 1 0 4 1 13

It will be observed in this table that most of the tags were recovered from Fanny bay, and that the number recovered there is greater, in each case, than the number recovered from the area of tagging. This probably shows that there is a movement of lemon sole from both ends of Baynes sound towards Fanny bay, the area of most active spawning.

49 .. it is concluded.that during 1946 spawning was most plentiful off Fanny bay and Cape Lazo. This was shown by systematic examinations of the reproductive organs of the fish and by following the movements of the fish by tagging. However, conclusions drawn from one year cannot be applied too generally. For instance, one trawler captain of long experience expresses the opinion that the greatest concentration of spawning fish in some years at least was in the southern part of Union bay adjacent to Fanny bay. Pacific Biological Station F. H. C. Taylor

Pacific Biological Station Exhibit

An educational, display at the Albern.i District Fall Fair, Sept. 5-7, 1946, illustrating tagging and marking meth.ods used to determine movements, migrations and growth rates of salmon, herring, pilchards, dogfish, lingcod and flatfishes.

50 F.IRST YEAR RETURNS OF LEMON SOLE TAGS USED OFF THE WEST COAST OF VANCOUVER ISLAND

Tags used on lemon soles (Parophrys vetulus) tagged off Florencia bay during June, 1945, show a suggestive pattern of recoveries. However, when interpreting these it must be kept in mind that recovery depends upon the activity of the fishing fleet and cannot be expected from areas in which there is no fishing. The present report is based upon the data made available by the recovery of 25 out of 130 tagged lemon soles. A tabulation of the recovery data .in relation to migration follows. It shows in boldface type the number of fish recovered in each general area and, in ordinary type, the actual distances travelled in nautical miles. The places of recapture of four of the fish are unknown or uncertain and are not considered further. Of the remaining twenty-one tags, eleven were recorded as being taken in the area of tagging, four fish having been recovered within three months of tagging and seven approximately one year after tagging. A southward movement to grounds ·off the southern end of the west coast of Vancouver island, Washington, and Oregon for the winter is shown by ten of the recovered fish. Nine of these remained free for periods of six to eight months or more and show the greatest distance travelled.

RECOVERED Months free Off west coast Off Off In In tagging of Vancouver area Washington Oregon uncertain island coast coast locations 0-2 4 1 40 3-5 1 6-8 s 1 3 50, 65, 65, 250 65, 125 9 - 11 6 1 2 40 50, 150 12 - 14 1

The results are consistent with the suggestion of a fairly general south ward movement in autumn and a return in the following summer, but the ·dependence of recoveries on· fishing activities makes premature any definite statement on the subject. The execution of this progr.amme was made possible by the assistance of several persons and agencies. To Mr. I. Car, from whose vessel, the "B. C. Maid," the fish were tagged; to Mr. W. E. Barraclough, who assisted with the tagging; and to the Canadian and American fishermen and fish house employees, and the Washington State Fisheries Laboratory who forw.arded the recoveries to the Pacific Biological Station sincerest thanks are tendered.

Pacific Biological Station J. I. Manzer 51 CONTROL OF RANCIDITY IN STORED FISH. III

Previous reports in this series described experiments in which was investigated the effect of certain chemical antioxidants, of different cold. storage temperatures (Progress Reports No. 64, pages 57-61, 1945) and of. storage in nitrogen or carbon dioxide gas (Progress. Reports No. 66, pages 17-20, 1946) on the development of rancidity in frozen fish. The present article deals with the value of ice "glazes" and of immersion in ascorbic acid (Vitamin C) solutions, in retarding the above mentioned undesirable change in fish steaks and fillets. Glazes with and without antioxidants Glazing whole frozen fish with a thin layer of ice prior to storing them has long been a commercial method for combatting drying and development of rancidity, or "rusting," of exuded fat during storage. Similar treatment of individual frozen steaks or fillets has also been suggested; in fact a United States patent taken out in 1928 covered the use of ordinary water glazes, or glazes containing a germicide such as sodium hypochlorite, for this purpose. Certain commercial firms located on this coast make a practice of freezing salmon whole and then sawing individual steaks from the frozen fish and glazing them as required. There is presumably less danger of the fish becoming rancid when treated in this manner than when it is packaged as fillets or steaks and then frozen and stored. The following are the results of typical experiments in which the development of rancidity in glazed and unglazed salmon steaks has been compared. Six. steaks about !! to ft'" thick were sawn from a red spring salmon and from a coho salmon, both of which had been frozen in still air, glazed and stored about 5 mortths at roughly - 20°F. After weighing them, two of the steaks from each fish were left untreated, two were glazed with distilled water and two with an 0.5% solution of ethyl gallate. The steaks were glazed in a room at about 0°F., the temperature of the glazing solutions being approximately 38°F. The average increase in weight of the steaks due to glazing was 7.25%. The steaks were wrapped individually in mois ture-proof cellophane paper and were stored at 14°F., the development of rancidity being followed as described in former reports. The results (table I) showed that glazing the steaks considerably retarded fat oxidation, and that, within the probable limits of error of. the methods, the ethyl gallate glaze was no better than the distilled water glaze.

TABLE 1.-Effect of glazing on development of rancidity in cold-stored red spring salmon and coho salmon steak&' (initial peroxide values: red spring salmon 0.5, coho ' salmon 1.2). Treatment Red spring salmon Coho salmo•n Peroxide value after days 28 79 28 79 Unglazed 2.3 17.6 3.2 21.3 Distilled water glaze 1.9 6.5 1.9 7.2 0.5% ethyl gallate glaze 1.6 6.7 1.9 5.8

52 In a further experiment, to compare the effects of glazes of different composition, ten steaks about f' thick, cut from a fresh red spring salmon, were wrapped individually in moisture-proof cellophane paper and frozen in still air at about - 20°F. Two of the frozen steaks were not glazed, and two were glazed for 10 seconds in each of the solutions, the composition of which is recorded in table II. In this experiment the glazing solutions were at 32 - 33°F., and the average increase in weight due to glazing the steaks was 6.5%. The steaks were wrapped, stored and tested as in the foregoing experiment. The results (table II) showed that a glaze formed from solutions containing 0.5% ascorbic acid, or 0.5% ascorbic acid which had been neutralized with alkali to pH 6 (sodium ascorbate solution), entirely prevented measurable fat oxidation during the storage period. On the other hand the glaze containing ethyl gallate was only a little better than the ordinary water glaze. In this, as in the previous experiment, rancidity developed much more rapidly in the unglazed steaks than in those with the ordinary ice glaze.

TABLE 11.-Effect of glazing on devefopment of rancidity in red spring salmon steaks (initial peroxide value zero). Treatment Peroxide value after days 41 84 Unglazed 4.0 8.5 Distilled water glaze 0.7 4.9 0.5% ethyl gallate glaze 0.6 1.8 0.5% sodium ascorbate glaze (pH 6) 0.2 0.2 0.5% ascorbic acid glaze 0.2 0.2

Ascorbic acid dips Fourteen fillets about 5 x 3 x i" in size were cut from a fresh red spring salmon, and two were dipped for 5 minutes in each of the solutions the composition of which is given in table III, drained, wrapped individually in cellophane paper and stored at 14°F. The dipping was carried out in a 32°F. room, the temperature of the solutions used being about 38°F. The results of this experiment (table III) showed that dipping the fillets either in ascorbic acid solutions or in almost neutralized ascorbic acid solutions strongly retarded fat oxidation in .the stored fish.

TABLE III.-Effect on development of rancidity of dipping recli s.pring salmon fillets· in solutions of ascorbic acid and sodium ascorbate (initial peroxide value zero). Treatment Peroxide value after days 4S 122 Dipped in distilled water 2.6 7.2 Dipped in 0.25% ascorbic acid solution 1.5 2.8 Dipped in 0.5% ascorbic acid solution o~ 1~ Dipped in 1.0% ascorbic acid solution 0.0 0.2 Dipped in 0.25% sodium ascorbate solution pH 6 1.1 3.5 Dipped in 0.5% sodium ascorbate solution pH 6 0.6 1.3 Dipped in 1.0% sodium ascorbate solution pH 6 0.0 0.2

·In another ~xperiment 12 fillets of the same size used in the above test were cut from two different red spring salmon. Three fillets were dipped for 5 minutes in each of the solutions the composition of which is recorded

53 TABLE IV.~Effect of period of immersion in 1% ascorbic acid solution on the ascorbic acid content and on the development of rancidity in red spring salmon fillets (initial peroxide value zero). Ascorbic acid Pet'oxide value present in the after days Treatment fillets, % 70 120 Untreated 0.0025* 3.4 10.1 Dipped 5 min. in 1% ascorbic acid 0.043 0.5 0.9 Dipped 10 min. in 1% ascorbic acid 0.057 0.3 0.5 Dipped 20 min. in 1% ascorbic acid 0.080 0.1 0.2 * Presumably this is the quantity of ascorbic acid in the normal untreated salmon flesh. in table IV, the conditions. of treatment being similar to those given in the previous experiment. One :fillet from each treatment was analyzed in order to determine the amount of ascorbic acid present, the remainder being wrapped individually, stored at - 4°F., and analyzed at intervals. The results (table IV) showed that the rate of fat oxidation in the treated fillets was greatly retarded and bore a close relationship to the amount of ascorbic acid present in the flesh. The experiments described showed that both the glazing and dipping methods of treatment can be successfully applied when using ascorbic acid or sodium ascorbate as an antioxidant. On the other hand glazes containing ethyl gallate were practically no better than ordinary water glazes in pre venting development of rancidity in stored salmon steaks, though tests recorded in a previous publication in this series showed that ethyl gallate dips were quite effective in this respect._ Apparently ascorbic acid is an effective antioxidant because it is able to remove oxygen from the tissues or to prevent access of atmospheric oxygen to them. Tests have indicated that 0.04% or more of ascorbic acid must be present in fish flesh in order that fat oxidation be retarded to an important extent, and that at the present price of ascorbic acid the cost of a dipping treatment might be about ic. per lb. of fish. Glazing individual steaks or fillets of fish might not be con sidered an entirely desirable method for: (1) it causes an apparent increase in weight of the fish, undesirable to the consumer, (2) the glaze may thaw after the fish is sold with the result that there is a quantity of free liquid in the package, (3) there is a tendency for the glaze to "soak" into the flesh on thawing which makes cooking less pleasant, especially should the fish be fried. Further tests. are being made .with . ascorbic acid,. sodium ascorbate and related compounds. I am indebted to Merck and Company and to Hoffmann-LaRoche Inc. for supplies of ascorbic acid, and to Mrs. F. M. Kwong and Miss K. Deas for technical assistance.

Pacific Fisheries Experimental Station H. L.A. Tarr

54 LAKES OF THE SKEENA RIVER DRAINAGE

· III. KITW ANGA LAKE*

About the middle of July, 1945, the Lakelse lake base camp for the lower Skeena river area became the scene of increased activity as two investigators began organizing a survey of the Kitwanga area. The best procurable maps of the district were carefully studied and copied. No permanent connection with any supply base or centre of communication could, be anticipated .so every detail of equipment, provisions and transportation had. to be sgttled. A six-week stay was contemplated s.o servicing trips had to be. axrang,ed in advance. The investigators had University responsibilities at a certain definite date which necessitated working out train and plane reservations to get them to Vancouver at the last possible minute before that date. For several days one could see various-sized gill nets being dried and rehung for packing, sample bottles being carefully rolled in paper and.tu.eked into boxes with cheµiical apparatus for oxygen and acidity tests. Rope, bags for fish stomachs, sounding lines, note books and other small artl.cles were pushed into the five-gallon preserving kits. The three-horse-power out board motor was cleaned, greased and tested. In the end everything· was loaded into the rowboat and taken to the waiting truck. To get to Terrace, ship the material and catch the train was easy. As happens in many cases the "passenger" reaches the village of. Kitwanga, about one hundred and fifty miles inland from the coast, i:µ the very early hours of the morning. This circumstance merely provided the investigators with a chance to test their sleeping bags and camping equipment in the railway station. As soon as the store openeq in the morning, groceries and incidental supplies were ordered in less than half an hour, thus .amply demonstrating the wisdom of making and remaking the list of requirements beforehand. The shortest, yet the hardest, part of the journey was about to begin. Twenty miles of dirt road wind along the valley of the Kitwanga river betwee11 the village and the nearest point on the lake andi the last few miles of this are little more than a muddy wagon trail-seldom used and over grown. A model T Ford of ancient vintage was rented locally. When loaded the springs were almost on the axles, but the party bumped along, unloading to cross uncertain bridges, reloading, fixing flat tires and digging its way out of mud holes. As is usual, steam kept drifting from the overheated radiator. Sad as it may seem, this turned out to be the last .such trip for the faithful old truck. Camp was established at the extreme southern end

* The third in a series presenting general information on the lakes of the Skeena river drainage particularly insofar as it affects salmon production. Previous ·articles in· this series appeared on pp.. 12-15 of issue No. 66 and pp. 23-26 of issue No. 67. 55 annually to the Nass to catch their supply of the oil-rich eulachon, or candle fish, Thaleichthys pacific11s. With the pitching of the tents completed, the first task before sounding the depths of the lake, netting fish or sampling the small aquatic food organisms, was to assemble the specially designed break-down boat four teen feet in length and wide of beam for stability. AIV the specially labelled parts were stowed in bundles in the load, even to templates, blue prints, caulking cotton, irons, screw nails, hammer, nails, paint and paint brushes. When the boat was floating, net racks, recording tables and measuring boards were designed and built for use on this and subsequent visits. During the next six weeks observations were made which would form the basis for classifying the lake as to its general importance in the whole Skeena river system, in fish food production, in size of salmon spawning areas and runs, and in "coarse" fish population-predator and competitor which might affect the young salmon during their fresh-water existence. Kitwanga lake, four and one-half miles long, was found to be divided into two parts, the larger northern portion being joined to the smaller southern one by a comparatively narrow channel. In general the shoreline was irregular in outline and stony, dropping off fairly rapidly to the mud and clay; bottom of the deeper waters. The greatest depth was only forty four fe,et in the southern section, while at either end and in several bays fairly extensive beds of horsetails, reeds and other water weeds indicated the shallow areas. During the summer, the surface temperature over the whole lake rose to about 18°C. (64.4°F.), but the thermal conditions in the lower waters of the two sections w~re somewhat different. Apparently wind action in the northern portion maintained partial circulation with the result that the bottom layers were only 3° to 5°C. (5.4° to 9°F.) cooler than the surface. On the other hand, marked thermal stratification occurred in the southern portion and, although the water here was only ten feet deeper, the bottom waters even in August did not rise above 7°C. (44.6°F.). The oxygen saturation of the lower strata in the northern part became somewhat reduced in late summer, but not to limits detrimental to fish ·life. In contrast, however, near the bottom in the southern section, the oxygen became almost completely exhausted. This absence of oxygen would pre clude fish living here in the region close to the bottom of the lake, but the condition was apparently purely loeal with the upper strata (above thirty feet) being quite habitable. The water of the lake was very clear and plankton sampling showed that there was an abundance of microscopic plant and animal life. The animal forms (Cladocera and Copepoda), the main food supply of the young sockeye salmon, were distinctly plentiful. . This combination of favourable physical and chemical conditions and a good basic food supply had apparently led to a relatively abundant "coarse" fish population. Ten species were obtained. From the gill net catches, the most abundant was found to be the squawfish, Ptychocheiltts oregonensis; feed ing largely on small fish and snails. Cutthroat trout, Sa/mo clarkii, were also present in considerable numbers. These are not fished to any extent for

56 N

KITWANGA LAKE CONTOUR LINES AT

TEN FOOT INTERVALS

(3.048 METRES)

SCALE MILES 0 10 1--~~~----,..-~~--1 0 1.0 KMS.

Map of Kitwanga lake showing· botto~ contourS/

57 sport, largely because of the isolation of the lake. The Dolly Varden char, Salvel.inus malma, the third and last of the predators, was fairly rare. Next to the squawfish in order of abundance were two species which feed either off the bottom or close to it, the Rocky mountain whitefish, Prosopium williamsoni, · and the chub or peamouth, Mylocheilus caurinus. The . long-nosed or northern sucker, Catostomus catostomus, the common sucker, Catostomus commersonii, and the prickly bull-head, Cottus asper, were taken in but few instances. The stickleback, Gcisterosteus aculecttus, and what was appar ently the lake shiner, Richardsonius balteatus, were found in cutthroat trout and squa wfish. stomachs. The population of sockeye salmon, Oncorhynchus nerka, was made up of two types, the usual sea-run fish ranging from 15 to 27 inches in length, and a smaller variety ranging from 7 to 9 inches. Scale markings indicated that these smaller individuals spend their whole life in the lake and are thus the Kokanee or land-locked sockeye. The sea-run sockeye move up the Kitwanga river from the Skeena in late July and early August and pass into the lake where they stay until mature. No observations of the actual spawning were made, but it appears th,at they move back down to the river in late September. to deposit their eggs. Spawning in the lake itself on gravel bars near the mouths of the small tributary streamlets may· also occur. The largest tributary to the lake enters at the north-eastern corner draining an extensive muskeg flat. It is entirely dissimilar from what· is considered a good salmon spawning stream since from .the point of entrance into the lake and for a considerable di.stance upstream, it is murky and slow flowing with little or no gravel in evidence on the bottom. Despite the fact that fairly large numbers of sockeye were observed in schools off its mouth during' the month of August not one was seen moving upstream. The beaches and the streams entering the lake seem singularly devoid of good spawning areas. Since the lake is small and the spawning grounds apparently limited, it is not surprising that the run of sockeye is1 correspond\ngly small. Direct counts at the head of the Kitwanga river in 1945 indicated that 6,000 to 7,000 sockeye moved in. Downstream all the way to the Skeena there were, however, large numbers of pink salmon,· Oncorhynchus ·gorbuscha. . Cohoes, Oncorhynchus kisutch are known to enter the system later in the autumn. Because the rooted aquatic vegetation is not overly abundant, the number of surface-feeding ducks present during the summer. is small. A few mallards were observed and one species of diving duck, the white winged scoter, was seen, The most common water bird is the loon, eight individuals being seen at one time. In early August, a family of American mergansers was a common sight on the upper reaches of the river. Throughout the Kitwanga valley and especially north of the lake toward the Cranberry river in the Nass drainage there are many signs of game such as moose, black bear, wolf, coyote and deer. These are taken occasion ally by the Indians and local white residents, but the area is comparatively virgin and "ui::thunted." . · Kitwanga lake may be coi:isidered in its broad aspects as similar to Lakelse lake and consequently a member of the second general group of 58 Skeena river lakes, i.e., rather shallow bodies of water, of moderate temper ature and relatively abundant in plant life. Its main deficiency insofar as salmon propagation is concerned is undoubtedly a serious lack of adequate spawning grounds. We are indebted to Dr. A. L. Pritchard for his assistance and efforts to facilitate the trip and survey and to Mr. H. Dean Fisher, who interrupted his work on hair seals at the coast to accompany one of the authors, Mr. J. A. McConnell. Pacific Biological Station J. A. McConnell J. R. Brett

Dr. Carter Still in Japan

Dr. N. M. Carter, Director of the Pacific Fisheries Experimental Station, who sailed for Japan from San Francisco on June 22nd is still in Japan investigating all phases of the fishing industry there. Several reports on his observations have been submitted by him to the Fisheries Department, Ottawa, from where release of the information immediately important to the industry will be made. No word has been received yet as to when Dr. Carter will return to Canada to resume his duties as Director of the Vancouver Station.

Visiting Chemists Work at Vancouver Station

Dr. H. 0. L. Fischer of the University of Toronto and Dr. H. A. Lardy of the University of Wisconsin spent several weeks in July at the Fisheries Experimental Station, engaged in a laboratory study of carbohydrate metabolism in the dogfish and the ra tfish.

They were not successful in finding evidenc~ to confirm their hypothesis that inositol, shown to be present in various tissues of the fish, is used by the fish as a reserve carbohydrate in the same way that mammals use glycogen. However, they found a remarkably high percentage of inositol in the testes of the dogfish and are planning further work to follow this up during the winter on material which will be sent to them from this Station.

59 NEWS ITEMS

Resignations from Vancouv·er Station Staff

Dr. J. M. R. Beveridge, Associate Biochemist, who joined the staff in June, 1944, resigned at the end of June of this year to join the teaching staff of the Medical Faculty of the University of Western Ontario. Prior to leaving he had completed several series of feeding experiments to determine the biological value of the flesh proteins from several species of Pacific coast fish and also to measure their content of the various B-vitamins. Mr. E. P. Sidaway, Scientific Assistant in Research Engineering, who joined the staff of the Experimental Station in Prince Rupert in February, 1941, resigned the end of June to take a position with the British Food Manufacturers' Research Association in Great Britain. While with the Fisheries Research Board Mr. Sidaway was engaged in canning and smoking experiments, and it was understood when he left that he would be continuing with this type of work in his new position. Neither position has yet been filled.

Pacific Sub-Executive Committee Meeting

The regular fall meeting of the Pacific Sub-Executive Committee of the Fisheries Research Board was held at the time of the visit of the Board's Chairman, Dr. A. T. Cameron, Aug. 26-31. All the western members of the Board. were present, namely, Mr. R. E. Walker, Dr. W. A. Clemens, and Mr. J. H. Deane. Major D. H. Sutherland, Honourary Secretary of the Board, was unable to attend because of the stress of departmental duties arising from his position as Acting Deputy Minister of Fisheries. Lt.-Col. H. B. Hachey, Oceanographer, Atlantic Biological Station, attended in order to carry back to the Hon. Secretary a verbal report on the meeting's deliberations.

During their week on the coast the Chairman of the Board and Lt.-Col. Hachey visited the Nanaimo and Vancouver Stations, interviewing staff members and discµssing with them the problems under investigatio!l.