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Vol.12, No.llA 



NOVEMBER 1950 -Supplement 



FISH and WILDLIFE SERVICE 

United States Department of the Interior 
Washington, D.C 



UNITED STATES m 

DEPARTMENT OF THE INTERIOR FISH AND WILDLIFE SERVICE 

OSCAR L. CHAPMAN, Secretary ALBERT M. DAY, Director 



COMMERCIALBt 
FISHERIESIU.1 

A REVIEW OF DEVELOPMENTS AND NEWS OF THE FISHERY INDUSTRIES 
PREPARED IN THE BRANCH OF COMMERCIAL FISHERIES 

A. W Anderson , Editor 
R.T Whiteleather, Associate Editor 
Wm. H. Dumont and J. Pi leggi, Assistant Editors 

Applications for COMMERCIAL FISHERIES REVIEW, which is moiled tree to members of the 

fishery industries and allied interests, should be addressed to the 

Director, Fish and Wildlife Service, United States Department of the Interior, Washington, 25, D.C. 

The contents of this publication hove not been copyrighted and may be reprinted freely; however, reference to 

the source will be appreciated. The Service assumes no responsibility for the occuracy of material from outside sources. 

The printing of this publication has Deen approved by the Director of the Bureau of the Budget, December 15,1949 

GONTENTS 

COVER: SOME OF THE ACTIVITIES OF THE U. S. FISH AND WILD- 
LIFE service's TECHNOLOGICAL LABORATORIES: 

1. CARRYING OUT PH T| DETERM I NAT I ONS . 

2. EXAMINING- PINK" YEAST CULTURES. (SEE P. 28) 

3. DRESSING SALMON FOR FREEZING TESTS. 

4. SECTION OF ANALYTICAL LABORATORY. 

PAGE 

THE TECHNOLOG I CAL SECT I ON A I DS THE F I SHER I ES 1 

FISHERY TECHNOLOGICAL RESEARCH PROGRAM, 1950-51 3 

INFORMATION ON PROGRESS OF TECHNOLOG I CAL PROJECTS ". . . 7 

UTILIZATION OF SALMON EGGS FOR PRODUCTION OF CHOLESTEROL, L I P I DE , AND PROTEIN, 

BY G. IVOR JONES, EDWARD J. CARR1GAN, AND JOHN A. DASSOW 8 

FEEDING STUDIES WITH THE GUM OF GRACI LlARI A CONFERVOIDES AND CARBOXY METHYL- 

CELLULOSE, BY HUGO W. N I LSON AND MAURI CE BENDER 15 

STUDIES ON ANALYTICAL METHODS OF EXTRACTING VITAMIN A AND OIL FROM FISHERY 

PRODUCTS -- PART IV - EXPERIMENTS ON THE EXTRACTION OF LOW-OIL-CONTENT LIVERS 

WITH ACETONE, ETHYL ETHER, AND PETROLEUM ETHER, BY F. BRUCE SANFORD AND 

Wl LLI AM CLEGG 18 

A CHEMICAL EVALUATION OF TUNA-LIVER AND BEEF-LIVER MEALS PREPARED BY DIFFERENT 

METHODS, BY G. IVOR J,ONES AND WILLIAM H. HOYER '. 21 

TECHNICAL NOTE NO. 5-- PINK YEAST ISOLATED FROM OYSTERS GROWS AT TEMPERATURES 

BELOW FREEZ I NG, BY GRACE MCCORMACK 28 

TECHNICAL NOTE NO. 6--VITAMIN-A POTENCIES OF LIVER OILS OF BER i NG SEA COD AND 

FLOUNDER, BY F. BRUCE SANFORD, JOHN A. DASSOW, AND ERNEST F. DIETRICH 29 

TECHNICAL NOTE NO. 7--RESULTS OF SOME TESTS WITH FROZEN LOBSTERS AND LOBSTER 

MEAT , BY S . R . POTT I NGER 31 



November 1950- Supplement Washington 25,D-C 



Vol .12, No. 11 A 



THE TECHNOLOGICAL SECTION AIDS THE FISHERIES 

The functions of the Technological Section (one of six=/ sections in the Branch 
of Commercial Fisheries, U. S. Fish and Wildlife Service) consist of research and 
field services for the fisheries and allied industries. The research activities in- 
clude field and laboratory investigations in chemistry, pharmacology, nutrition, bio- 
chemistry, and bacteriology. 

Four research laboratories are maintained by the Technological Section. These 
are located in Boston, Mass.; College Park, Md. ; Ketchikan, Alaska; and Seattle, 




FISHERY TECHNOLOGICAL LABORATORY IN COLLEGE PARK, MD., LOCATED ON THE CAMPUS OF THE UNIVERSITY 
OF MARYLAND. (THE LABORATORY SERVING THE NEW ENGLAND AREA IS LOCATED IN THE APPRAISERS STORES 

BUILDING, IN BOSTON, MASS. 

1/THE OTHER SECTIONS OF THE BRANCH ARE ECONOMICS AND COOPERATIVE MARKETING; EDUCATIONAL AND 

MARKET DEVELOPMENT; EXPLORATORY FISHING AND GEAR DEVELOPMENT; FISHERY MARKET NEWS; AND 

STATISTICAL. 



COMMERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 



Washington. A fifth laboratory in Mayaguez, Puerto Rico, is no longer operating 
because of lack of funds. 

The Section is particularly concerned with research and development problems 
peculiar to the fishery industries; i.e., the utilization of fishery products. 




FISHERY TECHNOLOGICAL LABORATORY IN SEATTLE, WASH., WHERE BOTH TECHNOLOGICAL AND BIOLOGICAL 
FISHERIES RESEARCH ARE CONDUCTED. 

In general, the specific activities of each of the laboratories are the same. 
These include studies on preservation, freezing, canning, sanitation, nutritive 
value, bacteriology, pharmacology, chemistry, and utilization of fishery byproducts. 
Mobile or trailer laboratories are maintained to enable chemical and bacteriological 
studies of the fisheries in the field in out-of-the-way places. 

Funds for technological work are allotted on a nation-wide basis and must be 
used to carry out studies of greatest importance to the industry as a whole. Be- 
sides these research and development studies, consulting services of the Section 
are at all times available to the entire industry on nearly all phases of commer- 
cial fisheries. 



At the beginning of each fiscal year (July 1), the chiefs of each of the 
technological laboratories meet in Washington to discuss the progress on the pre- 
ceding year's program and to develop a new program for the next fiscal year. Mem- 
bers of the fishing and allied industries are invited to attend the meeting and 
to offer their comments, criticisms, and suggestions. These meetings with members 
of industry have aided the Branch considerably in establishing the commercial fish- 
eries technological research program on as sound a basis as funds and facilities 
permit. The last meeting was held on June 28, 1950, when the following program 
was developed for the fiscal year 1950-51, beginning July 1, 1950. 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 



FISHERY TECHNOLOGICAL RESEARCH PROGRAM, 1950-51 

Nutrition 

1. *Effect of low and high temperatures on chemical properties of proteins . — 
An investigation will be made into the way in which water is bound to protein. When 
fish is frozen the first change is separation of the water from the protein. Upon 
thawing there is the question of whether the water returns to its original relation- 
ship to protein. The study will include some preliminary work on isolation and iden- 
tification of fish proteins and possibly a study of some of their properties and re- 
actions, such as, isoelectric point, heat denaturation, etc. These investigations 
might lead to important advances toward an understanding of the nature and control 
of drip, possibly information on the toughening of f^.sh in cold storage, etc., and 
would also be of importance to drying of fish, such as fish meal, and dehydration 

of fish. (Seattle) 

2. Utilization of salmon cannery waste for hatchery food . — Work of the preced- 
ing year was concerned with: 

(a) Collaborative work with other State and Federal agencies 
in the analysis of mixed diets and special diet components 
for chemical proximate analyses and vitamin content; 




FISHERY PRODUCTS LABORATORY IN KETCHIKAN, ALASKA. OPERATED JOINTLY BY THE FISH AND WILD- 
LIFE SERVICE AND THE FISHERIES EXPERIMENTA L COMMISSION OF ALASKA. 

* NEW PROJECT. 



COMMERCIAL FISHERIES REVIEW Vol. 12, No. 11a 



(b) Collection of raw material such as hake and other fish for 
hatchery feeding tests; and 

(c) Preservation and processing of raw material, particularly 
tests on salmon eggs at relatively low temperatures using 
various chemical preservatives and antioxidants. 

In view of the promising results in feeding tests with salmon eggs, the studies 
will be continued with special emphasis on completing the work on the preservation 
of salmon eggs. Suitable methods of preserving salmon eggs for hatchery food would 
allow the tapping of a considerable portion of the Alaska resources, now conmonly 
wasted, and which totals in excess of 8,500,000 pounds annually. (Seattle) 

3. Clam processing methods and clam toxicity survey . — Tests indicate in part : 

(a) That toxin is present in butter clams of Alaska from certain 
areas during every month; 

(b) The siphons are several times greater in toxicity than are 
the bodies of the clams; 

(c) Rate of toxin loss in highly toxic clams transplanted into 
a relatively non-toxic beach is very low; and 

(d) Suitable commercial packs of canned minced clams are feasible 
when processed by recommended methods of the laboratory. 

The remaining experimental work will be completed during the next fiscal year. 
(Ketchikan) 

Refrigeration 

1. Freezing fish at sea , defrosting , filleting , and refreezing the fillets . — 
Laboratory tests indicate the superiority in regard to appearance, taste, and tex- 
ture of frozen fillets prepared from fish frozen in the round immediately after 
catching as compared to frozen fillets prepared from fish which were first gutted 
and iced for a 10-day period. Laboratory tests have now proceeded to a point where 
commercial scale tests are warranted. Additional laboratory studies will be directed 
toward obtaining information on: 

(a) Effect of prolonged storage of frozen round fish prior to 
defrosting and filleting; 

(b) Ratio of brine to fish necessary for optimum freezing; 

(c) Absorption of brine by fish; 

(d) Effect of rate of freezing or temperature of brine on 
quality of fish; 

(e) Viscera yield from round fish; and 

(f) Thawing methods. (Boston) 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 5 

2. Study of fresh and frozen oysters.— This project is being continued and 
was initiated with a view toward developing and improving methods of freezing, pack- 
aging, storing, and testing oysters. These studies include, specifically: 

(a) pH determinations of fresh and frozen shucked oysters; 

(b) Prevention of discoloration in frozen oysters; and 

(c) Packaging of frozen oysters. (College Park) 

3. Studies o f methods of handling frozen salmon to be used for canning . — 
Processing difficulties have developed and some commercial canned packs prepared 
from frozen salmon were of inferior quality. The practice of preparing packs from 
frozen fish is being adopted in certain instances by various processors where the 
fish is caught and frozen in remote areas and canned at existing canneries else- 
where. Experimental studies on frozen red (sockeye) salmon indicated that the fla- 
vor and texture of the canned red salmon prepared from the frozen fish was signif- 
icantly adversely altered in comparison with the red salmon canned from fresh fish 
of the same lot. Additional studies will be made on the effect of storage temper- 
ature and freezing variables on the quality of the final canned product. (Ketchikan) 

4. Freezing pink salmon . — Freezing tests to date indicate the improvement in 
keeping quality of frozen pink salmon fillets due to ascorbic acid treatment, supe- 
rior packaging methods, and storage of the fillets at -20° F. The present series 
are to be completed. A commercial scale test is warranted and will be carried out 
as the interest and cooperation of the industry indicate. (Ketchikan) 

5. * Freezing and storing Alaska shrimp and dungeness crabs. — Development of 
new and improved methods of freezing and storing Alaska shrimp and crabs is impor- 
tant in the development of the local industries. Studies on shrimp are to be made 
on a limited basis on effect of precooking variables and packaging conditions on 
the quality of the stored frozen shrimp. Studies on dungeness crabs will consider 
packaging methods with new type containers. (Ketchikan) 

6. * Palatability and cold storage life of various species of Pacific Coast 
rockfishes . — A study will be directed to determine whether certain species of Pa- 
cific Coast rockfishes are of sufficiently superior quality to the other species 
to warrant separate marketing. (Seattle) 

7. *Preparation of a_ manual on the refrigeration of fish . —The preparation of 
a complete manual on the refrigeration of fish has been authorized. 

Processing and Preservation 

1. Canning of " little tuna. " — Packs to date indicate that it is possible to 
prepare a canned product of commercial quality. The present experimental tests 
will be carried out to completion. (College Park) 

2. *Evaluatlon of the antibiotic " subtilin" as a_ preservative for fishery 
products . — Tests by the Department of Agriculture showed promising results in the 
use of "subtilin" in the preservation of canned fruits and vegetables. Subtilin 
is an antibiotic produced by some strains of the bacterium Bacillus subtilis under 
proper culturing conditions. Its experimental use as a preservative in certain 
canned food products allows shorter p rocesses resulting in a quality product of 

*NEW PROJECT. 



COmERCIAL FISHERIES REVIEW Vol. 12, No. 11a 



better appearance and taste than those prepared by the normal processing methods. 
Attempts will be made to apply subtilin to the preservation of certain fishery 
products. (Boston, College Park, and Seattle) 

Sanitation and Bacteriology 

1. A bacteriological survey of the preparation of crab meat. — Limited studies 
begun during the last year are to be supplemented with further work to establish 
recommended practices for the handling of highly perishable crab meat, making use 
of such data on the subject as have already been collected by laboratory personnel. 
(College Park) 

2. *Grovrth of pink yeast ( isolated from oysters ) at below freezing tempera- 
tures . — A "pink" yeast was isolated from an active culture found on oysters stored 
at 0° F. Further studies are to be carried out on the cultural characteristics and 
the physiology of the organism with a view toward its control in the oyster indus- 
try. (College Park) 

Analysis and Composition 

1. *Chemical composition of fish , (A) Menhaden . — Complete analyses are to be 
made of certain fish, beginning with menhaden, for chemical proximate analyses, pro- 
teins and protein degradation products, vitamins, and biologically active compounds 
with a view towards determining the over-all potential commercial value of the fish. 
(College Park) 

2. Cooperative work with the Association of Official Agricultural Chemists on 
the determination of oil in fish meal . — Further tests on the improvement of methods 
for the determination of oil in fish meal are to be conducted in the light of knowl- 
edge gained on earlier tests and to pursue newer ideas on the subject. The present 
methods are inadequate and give results as much as 20 percent of true value. Ac- 
curate testing methods are necessary to avoid confusion between buyer and seller of 
fish meal. (Seattle) 

Byproducts 

1. * Vitamin content , particularly animal protein factor and vitamin B-|g> of 
fishery byproducts . — Analysis and feeding tests are to be conducted on fishery by- 
products (fishmeai and solubles) to determine the potential value of the products 
in animal and poultry feeding. (College Park and . eattle) 

2. Utilization of salmon cannery waste for mitiwl food — Cooperative tests with 
the Petersburg , Alaska , experimental fur farm . — Work- will be continued on collect- 
ing analyzing, and processing salmon waste in connection with cooperative studies 
with the U.S. D.A. , Petersburg, Alaska fur farm, on use of salmon waste as feed 
for fur farm animals. (Ketchikan) 

3. * Preparation of a_ manual on the fish meal and oil industry . — The preparation 
of a complete manual on the fish meal and oil industry has been authorized. 

***** 

In addition to the above projects, several carried over from the preceding year 
will be written up and reports completed during the first and second quarter of this 
fiscal yoar. These include: 

* NEW PROJECT. — 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 7 

1. Determination of food value of fishery products as prepared 
for serving . 

2. Correlation of biological and spectrophotometry methods for 
the determination of vitamin A potencies . 

3. Effect of fluctuating temperatures on quality of frozen fish 
in storage and in transit . 

4. Frozen storage of certain Pacific Coast fish, second report . 

INFORMATION ON PROGRESS OF TECHNOLOGICAL PROJECTS 

Current information regarding the progress on the various projects is presented 
in Commercial Fisheries Review (CFR) in the section "Research in Service Laboratories. 

More detailed information on the projects may be obtained by the fishery and 
allied industries by writing directly to the Branch of Commercial Fisheries, Fish and 
Wildlife Service, Washington 25, D. C. ; to the laboratories ;i/ or by consulting with 
members of the Technological Section. Phase or final reports on projects are usually 
published in Commercial Fisheries Review , as fishery leaflets (FL) or scientific re- 
ports, or in non-governmental scientific journals. Abstracts of these and other 
current information pertaining to commercial fisheries are available in Commercial 
Fisheries Abstracts ( CFA) . 

CFR, CFA, FL, and most scientific reports are available free to members of the 
fishery and allied industries on request. Some of the special scientific reports 
are sold by the Superintendent of Documents, Government Printing Office, Washington 
25, D. C. 

l/SEE INSIDE BACK COVER OF THIS I SSUE FOR ADDRESSES OF LABORATORIES. 




PACKAGING FROZEN FISHERY PRODUCTS 

The requirements for satisfactory containers for frozen fishery 
products are no less rigid than for other frozen products. The choice 
of the package is very important in protecting and merchandising the 
product. The problem of vital importance is that of preventing loss 
of moisture from the product. The use of packaging materials having 
low water-vapor transmission rates must be emphasized. A package made 
of suitable water-vaporproof materials which will satisfactorily with- 
stand low storage temperatures without becoming brittle or otherwise 
unsatisfactory and which is tightly sealed, will provide adequate pro- 
tection for a long period of frozen storage. 

—Fishery Leaflet 324 



8 COmSRCIAL FISHERIES REVIEW Vol. 12, No. 11a 

UTILIZATION OF SALMON EGGS FOR PRODUCTION OF 
CHOLESTEROL, LIPIDE, AND PROTEIN 

By G.Ivor Jones""" Edward J. CarriganYand John A. Dassow" 

ABSTRACT 

Quantitative determination of cholesterol, fat, phospholipids, and protein 
were carried out on the roe (egqs) of five species of salmon. The cholesterol 
content was found to vary from 0.29 to 0.40 percent, on the raw-ego basis. When 

CALCULATED ON THE LIPIDE FRACTION ( ETHER-SOLUBLE FAT = I I.I TO 13.9 PERCENT OF 
THE WHOLE EQQ), THE CHOLESTEROL VARIED FROM 2.2 1 TO 3.53 PERCENT. 

PRELIMINARY ANIMAL-FEEDIN3 STUDIES SHOWED THAT THE DEFATTED SALMON EGG PROTEIN 
COMPARED FAVORABLY WITH CASEIN IN NUTRITIONAL QUALITY. PROTEIN CONTENT OF THE ROE 
VARIED FROM 22.5 TO 28.8 PERCENT AND THE ASH CONTENT FROM 1.3 TO 2.7 PERCENT. 

PhOSPHOLIPIDE, BASED ON THE PHOSPHOROUS CONTENT OF THE LIPIDE FRACTION, RANGED 
FROM 10.4 TO J2.4 PERCENT OF THE EGG ( MOISTURE-FREE BASIS) OR 25.8 TO 39.2 PERCENT 
OF THE ETHER-SOLUBLE FAT. 

UTILIZATION OF SALMON EGGS FOR THE EXTRACTION OF THE RELATIVELY SMALL AMOUNT 
OF CHOLESTEROL PRESENT IS UNWARRANTED AT THIS TIME. HOWEVER, COMMERCIAL 
EXPLOITATION OF THE LIPIDE AN3 PHOSPHOLIPIDE FRACTIONS ANO PERHAPS THE PROTEIN OF 
SALMON ROE APPEARS TO BE PRACTICAL. 

INTRODUCTION 

Attention was directed to an investigation of salmon eggs as a possible com- 
mercial source of cholesterol, lipide, and protein by the findings of a preliminary 
survey by Jones and Carrigan (19^7) carried out during the initial stage of the 
research program on utilization of Alaskan salmon-cannery waste. The period of 
study was necessarily limited to the six months' contract of the Industrial Research 
and Development Division of the Office of Technical Services with the Alaska Fisheries 
Experimental Commission, under which the investigation was possible. Accordingly, 
the experimental work was arranged so that the information required to evaluate 
the possibilities of further development could be collected in the allotted time. 
From analytical data reported in the literature, the use of salmon eggs as a source 
of cholesterol appeared promising. It was hoped that commercial development might 
be practical if experimental tests showed the salmon eggs under study to be as 
high in cholesterol content as had previously been reported. 

It was believed very likely that in addition to cholesterol extraction, 
processes could be developed which would also permit recovery of a high quality 
protein meal from salmon eggs as well as a fat or lipide fraction which might 
have a number of important industrial applications. 

The presence of cholesterol in the roe of fish has been reported on by 
several investigators. Koenig and G-rossfeld (1913) reported that the fat from 
fish roe contains from k to lb percent cholesterol. Anno (19*4-0) found that the 
unsaponifiable matter present in the lipides of salmon eggs was essentially 
cholesterol. In addition to cholesterol, the liuide fraction of fish roe has a 



* Biochemist ) Fishery Technological Laboratory, 8ranch of Commercial Fisheries, u. S. Fish and 
** Chemist ) wildlife Service, Seattle, Washington. 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 9 

high content of lecithin. Koenig and Grossfeld (1913) in considering fish roe 
as food for man found the egg fat to contain as much as k$ percent lecithin. 
Halpern (19^5) reported that the roe from sockeye salmon ( Oncorphynchus nerka ) 
yielded 12.5 percent oil and 6.2 percent phospholipide. 

The separation of lecithin from the extracted egg fat would appear to he 
easily accomplished by a process developed by the German oil industry and described 
by Goss (19^7). In this process, the lecithin is removed from the crude fat or 
oil by washing it with 2 to 5 percent by volume of hot water and removing the 
resulting sludge in a centrifuge. Two successive washings are required to insure 
maximum recovery of lecithin. The lecithin is recovered from the sludge by 
removal of water at 60° C. with the aid of vacuum-, followed by a bleaching of the 
residue with hydrogen peroxide. Residual oil remaining in the lecithin is then 
recovered by repeated extractions with acetone. 

Recovery of a semipurified protein of high nutritional quality may have 
considerable importance in the economic utilization of salmon eggs. The protein 
content of salmon eggs varies from about 22 percent in king or chinook salmon 
to about 28 percent in the chum.i/ 

The quantities of salmon eggs available in Alaska for processing are enormous. 
Since the eggs constitute about 8 to 10 percent of the entire salmon-cannery waste, 
which amounts to more than 100,000,000 pounds annually, it can be readily calcu- 
lated that about 9,000,000 pounds or il-,500 tons of salmon eggs are at present 
discarded each year. 

Collection of the raw salmon eggs in Alaska should not interpose any very 
difficult problems. The salmon are dressed prior to canning in a machine known 
as the "Iron Chink n which in a single cycle cuts off the head, fins, tail and 
removes the viscera. The eggs as a part of the viscera, are swept out of the 
body cavity in the middle cycle of the rotating wheel of the "Iron Chink." 
Separation of the eggs from the rest of the abdominal contents would necessitate 
hand sorting to only a moderate degree. The large and, in most cases, intact 
skeins of salmon eggs could be readily separated from the other waste parts 
while they are traveling along a belt, chute, or trough. 

Problems of handling and storing salmon eggs for subsequent processing are 
expected to be somewhat easier to overcome than those of other fractions of 
salmon-cannery waste, because the eggs are individually encased in a tough semi- 
permeable membrane and the entire egg mass is held together in a skein structure 
which offers ease of handling and some protection from contamination. If it were 
found necessary to hold or store the salmon eggs for a considerable period of time 
before processing, this no doubt could be accomplished by salting, freezing, or 
by addition of a chemical preservative. Salmon eggs appear to offer a unique 
material for chemical processing due to their special constituents and because 
of the size of the roe in salmon waste and the enormous quantity that is avail- 
able in Alaska. 

EXPERIMENTAL PROCEDURES 

Before accurate assessment of the possibility of recovering cholesterol 
from salmon eggs could be made, it was necessary to determine the quantity of 
cholesterol present in this portion of the cannery waste as it occurs in Alaska. 
Since a complete survey of the variation in cholesterol content due to size of 
fish, maturity, and location of capture, would require an expenditure of a large 



1/ UNPUBLISHED DATA OF THE AUTHORS. 



10 



COMMERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 



amount of time and money, it was decided, to limit the preliminary analysis to a 
sample of eggs from 25 to 100 fish of each species. It was believed this sample 
would furnish a fairly representative approximation of the cholesterol content 
to he encountered. 



The egg samples for the analyses presented in the following report for all 
species of salmon, except king or chinook, were collected during the 19^7 fishing 
season at two salmon canneries located at Ketchikan, Alaska. The samples of king 
eggs were collected from Columhia River chinook salmon at a cannery located at 
Astoria, Oregon. Each sample of approximately 35 pounds of raw eggs represented 
the roe from 25 to 100 salmon of the individual species. Samples of each species 
other than king were obtained directly from the "Iron Chink" butchering operation 
with no attempt to segregate the material according to size or maturity. The 
saliron were trap-caught, in most instances, and represented fish of average size 
which were semi-mature, as evidenced by development of the gonads. The eggs were 
inspected for the presence of other waste parts before being sealed in five-gallon 
tin containers and frozen in a sharp freezer at -20° E. , within k hours after 
collection and about 24—36 hours after the salmon were caught. All samples were 
held at 0° E. storage until thawed and ground prior to chemical analysis. 

Each analysis in Table 1 was 
made on a representative sample 
drawn from the entire 35-pound 
lot of thoroughly mixed ground 
eggs. This small representative 
sample of about 250 to 300 grams 
was blended in a Waring 
Blendor prior to removal of a 
sample for the determination of 
cholesterol and ether-soluble 
fat. The value reported for 
king or chinook eggs was de- 
termined on a representative 
sample drawn from a 35-pound 
lot collected at Astoria, Oregon, 
during August 19^-7. Due to the large size of this species, a 35-pound sample of 
eggs represents only 15 to 20 fish. 



Table i - Average Cholesterol and Fat Content of Salmon 


Egos 




Species of 
Salmon 


Cholesterol 




In Raw Eggs 


In Fat 


Fat!/ 




Percent 


Percent 


Percent 


Pink 


0.29 


2.61 


II. i 


Red 


0.39 


2.82 


13.9 


Chum 


0.38 


3.15 


11.9 


Chum, dehydrated 


o 86 


3.05 


28.0 


KING 


0.34 


2.64 


12.8 


COHO 


0.40 


3.53 


11.4 


jj Total ether extract after acid hydrolys 


is or 


SAMPLE. 





CHOLESTEROL DETERMINATION 

Numerous methods for the quantitative determination of cholesterol are 
found in the chemical literature. However, many of these methods are modifi- 
cations of the Lieberman-Burchard reaction, and are designed primarily for the 
determination of small quantities of cholesterol present in blood. Methods commonly 
used for the determination of cholesterol in hen egg yolks or in other food 
products containing egg yolk appeared to be the most logical to use for the 
analysis of salmon eggs. Accordingly, the method described in Methods of Analysis 
of the Association of Official Agricultural Chemists . VI Edition, 19^5, page 3^9, 
for determination of cholesterol in eggs and egg products was used in the initial 
experiments on salmon eggs. In this method the cholesterol is isolated from a 
saponified sample as the dibromide and subsequently determined by an iodine 
liberation-titration method using sodium thiosulphate. This method is considered 
precise and accurate, but has the disadvantage of being laborious and time 
consuming. In order to examine a larger number of samples, a simpler method was 
resorted to after a preliminary check analysis had been made using an aliquot 
of the same sample in the determination of cholesterol by both the A.O.A.C. VI 
method and the coloriraetric method of Cook and Mehlenbacher (19^6). The Cook 
and Mehlenbacher method is based on the Lieberman-Burchard color reaction for 
cholesterol using the unsaponlfiable fraction of the ether extract. Cook and 
Mehlenbacher suggested the use of a lower temperature during color development 



November 1950 - Supplement 



COMMERCIAL FISHERIES REVIEW 



11 



and subsequent reading and also the use of a spectrophotometer to obtain the 
transmittance values. 

Initially the cholesterol content of dehydrated (lyophilized) chum salmon 
eggs was determined by the A.O.A.C. method. The amount of cholesterol calculated 
on the basis of the total oil fraction was found to agree within the limits of 
experimental error with that found for the oil from raw eggs when analyzed by 
the colorimetric method. Subsequent values for cholesterol in salmon eggs were 
determined in duplicate by the colorimetric procedure. It was not necessary to 
use more than two to three grams of ground salmon eggs for each analysis. With 
this small sample, it was possible to saponify the eggs directly by addition of 
30 ml. of 95 percent ethanol and J ml. of 5° percent KOH followed by refluxing 
on a steam bath for 30 minutes. The combined ether extractions of the unsaponi- 
fiable fraction were washed with distilled water until the washings were neutral 
to phenolphthalein . The extract was then made up to a volume of 100 ml. with 
ethyl ether. Five ml. aliauots were placed in dry test tubes for color development; 
the ether was removed by immersion in a water bath maintained at 60° C, and 5 nil. 
of C. P. chloroform were added when the ether had evaporated. The color was 
developed at 18° C. for 25 minutes in accordance with the Cook-Mehlenbacher 
technique using acetic anhydride- sulfuric acid mix. The period of color develop- 
ment was not critical as it was found that a period from 20 to 30 minutes gave 
reasonable good agreement on replicates. Transmittance values were determined at 
6^*0 mmu. with a Beckman spectrophotometer using 1 cm. corex cells. Values were 
obtained from the t ransmittance-concentration curve with a range of 0.2 to 0.60 mg. 
cholesterol per 5 ml. chloroform. Blank determinations showed no absorption caused 
by impurities in the reagents used. 

Transmittance values for known amounts of cholesterol subjected to color 
development are shown in Figure 1. 



0.6 
0.5 

0.4 

> 

w 0.3 

z 

Ul 

a 

_|0.2 

< 


I 0.1 




















FIGURE 1 - 

STANDARD CURVE 

FOR CHOLESTEROL. 
















~^- 


















-— - 















° 


O.I 0.2 0.3 0.4 0.5 
MO. CHOLESTEROL 


6 



The values for cholesterol present in salmon eggs of five different species 
of salmon are given in Table 1. 



These data indicate that the cholesterol content of salmon eggs lies near the 
lower part of the range of k to 1^ percent cholesterol in fish-roe fat as reported 
in the literature. For comparison purposes, it is pointed out that the fat fraction 
of hens' eggs contains an average of k,Zk percent cholesterol as compared with 3.53 
percent cholesterol in the fat of coho salmon eggs. 



12 



COMMERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 



Anno (l) reported that 
pink salmon was es- 
sentially cholesterol. 
Observations made 
during the present 
study failed to con- 
firm this report. As 
indicated in Table 2, 
approximately one- 
half of the unsaponi- 
fiable matter did not 
respond to the reactions 
for cholesterol. 



the unsaponifiable matter extracted from the eggs of 



Table 2 - Cholesterol Content of the Unsaponifiable mattes 




of Salmon Eggs 




UNsAPoN UNABLE 




Cholesterol In 


Species or 


RESIDUE Xj 


Cholesterol 


THE UNSAPONIFI- 


Salmon 


IN FAT 


IN FAT 


ABLE RESIOUE 




Percent 


Percent 


Percent 


Pink 


5.44 


2.16 


48 


Red 


4.44 


2.82 


64 


Chum 


6.46 


3.15 


49 


K|NQ 


5„|6 


2.69 


52 


Coho 


7.10 


3.53 


50 


j/ Unsaponifiable residue 


DETERMINED by A.0 o A.C. VI 


methods of Analysis. 





PROTEIN, FAT, AND LECITHIN RECOVERY 

In order to obtain the lipide fraction and protein fraction of salmon eggs 
for evaluation, an extraction process was developed using acetone directly on the 
raw salmon eggs. In this process, the acetone removes the water content of the 
egg and a major portion of the fat. Pinal extraction of some of the remaining 
lipoidal material is accomplished with hot ethanol. By distillation of the acetone- 
water-fat solution at atmospheric pressure, the solvent is recovered and the oil 
or fat separates as a layer on top of the water in the still pot. The oil is then 
separated from the water by decantation. 

The pilot plant studies carried out on the acetone extraction of salmon eggs 
will not be included in this report. A sufficiently large quantity of protein 
meal and salmon egg fat were prepared for evaluation studies. The protein meals 
prepared by the acetone extraction process had the following average composition: 
protein, Sh.1 percent; moisture, 9.7 percent; fat, 2.1J- percent; and ash, 3.1 
percent. 

A study of the salmon egg protein meal to determine its nutritional value 
and also to observe any possible toxicity towards rats was carried out. The 
authors had received a personal communication to the effect that white rats could 
not survive on a diet containing salmon egg meal as a source of protein. Accord- 
ingly, a feeding study l/ was undertaken to evaluate the salmon egg protein in 
comparison with casein. 



Basic diet for the groups fed was as follows; 

Basic Diet 

Protein Zj 

Dextrin, tapioca 

Sucrose 

Lard 

Cod-liver oil 

Wheat embryo 

Brewers 1 yeast, dry 

Liver extract, Lilly 

Mineral mixture, USP XIII, No. 2 



Percent by weight 
30 
20 

25.5 
15 

2 

2 

2 

0.5 
3 



U Carried out at the Service's College Park Fishery Technological Laboratory. 

Zj for the control group, 25-percent technical casein and 5-percent dextrin were substituted for the 
30-percent salmon egg protein. 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 



13 



White rats were allotted to the two groups at random and kept in individual 
cages. Food and water were allowed ad libitum. Data, including rat weight and 
food consumption, were recorded weekly. Gain in body weight to food consumption 
was calculated and is presented in Table 3. 

The data show that 
the rats on the diet con- 
taining salmon egg protein 
grew about as well as those 
fed casein. No gross 
symptoms of toxicity were 
manifested at the termi- 
nation of the experiment. 
While it is realized that 
these experiments are not 
extensive, they do indicate 
that no acute toxicity resides in the defatted salmon egg meal and that the 
nutritional value appears to be very nearly equivalent to that of casein. 



Table 3 - Evaluation of Salmon Eqq Protein meal for Growth of Rats 


DIET 

Designation 


SFX 


Initial 
Weight 


Length of 
Experiment 


Gain in 

LlVEWEIGHT 


Food 
consumed 


NAT 10 OF 
Grams of Food 
to Grams of 
Gain in Weight 
of Rat 


SASEIN 


M 

M 

M 


grams 
75 
82 
42 


weeks 

4 
4 
4 


grams 
88 
80 
79 


GRAMS 
216 
219 
215 


2.5 
2.7 

2.7 


<ING SALMON 
EQQ PROTEIN 


F 

M 
F 


88 

69 
45 


3 

4 

3 


30 

HO 
41 


203 

225 
131 


2.5 

2.0 
3.2 



RECOVERY OF SALMON EGG FAT 

The solvent in the acetone-water solution of salmon egg extractives was 
removed by distillation in a simple pot still at atmospheric pressure. The major 
part of the acetone was recovered by heating the mixture to 60° C. From all ap- 
pearances this temperature was not measurably destructive to the lipide fraction 
which separated out as an oily layer. This oil layer was removed by decantation 
and subjected to further solvent removal at reduced pressure. The water phase was 
discarded after decantation. The final ethanol extract was also concentrated and 
the extractives added to the acetone soluble lipides. The resulting oil was a 
dark red color. In order to abstract some of the dark color and to refine the 
product further, the phospholipides were separated out by dissolving the oil in 
ether and adding acetone until no further precipitate formed. After precipitation 
of the lecithins by two repeated treatments with acetone, the solvent was removed 
from the oil fraction by distillation. The oil now possessed a light pinkish-red 
color which exhibited no tendency to darken upon standing. The acetone- 
precipitated sludge of phospholipides was freed of any residual oil by repeated 
extraction with acetone. Some darkening of the product, a light-brown greasy 
solid, occurred as the purification steps proceeded due undoubtedly to exposure 
to air during the processing steps. 

The process of fat and 
phospholipide ^fractionation was 
applied to the solvent ex- 
tractives from the eggs of four 
species of salmon. Yields of 
the separate fractions are given 
in Table 4. 

As indicated in Table h, 
the phospholipide fraction 
constitutes about one-third of 
the total fat. It appears that 

recovery and partial purification of the lecithin fraction of the extracted fat 

would be relatively simple. 



Table 4 - Phospholipide Content of Salmon EggsL' 


SPECIES 


iotal 








or 


Ego 


Phospholipide!/ 


Phospholipide!/ 


Phospholipid^/ 


Salmon 


FAT2/ 


in Egg 


in Egg 


in Fat 


PINK 


Percent 


percent 
13.6 


Percent 
11.7 


Percent 
33.4 


35.0 


RED 


43.0 


12.3 


It.l 


25.8 


Chum 


26.5 


12.9 


10.4 


39.2 


Coho 


38.0 


15.3 


12.4 


32.6 


if All values are given on a moisture-free basis. 




2/ Ethyl-ether soluble fat. 




3/ Halpern (|945) selective extraction method. 




A] Phosphorous determination, A.O.A.C. V, p. 2|. 




5/ Based on the phosphorous determination. 





14 COMMERCIAL FISHERIES REVIEW Vol. 12, No. 11a 



DISCUSSION AND SUMMARY 

One of the purposes of this investigation was to determine the possibility 
of utilizing salmon eggs from Alaskan salmon cannery waste for the production of 
cholesterol, lipide, and protein. Some of the references in the chemical liter- 
ature held promise that salmon roe would prove to he an especially valuable source 
of cholesterol. Our observations have shown salmon eggs to be only average in 
cholesterol content, for example, approximately the same as hens' eggs. In view 
of these findings it appears unlikely that salmon eggs could be profitably pro- 
cessed for their cholesterol content alone. However, the protein, fat, and 
lecithin fractions prepared by solvent extraction of the raw eggs appear to be 
of high quality and to offer promise of economic recovery. The egg protein, 
fudged on its appearance, odor, and preliminary nutritional evaluation appears 
worthy of further study. It is also possible that ' salmon egg protein may possess 
special properties desirable in certain industrial applications, such ae the 
sizing of paper, manufacture of plastics, etc. 

The saLr.on egg fat fractions, either combined or separated into glyceride 
and phospholipids portions, seem to be worthy of commercial exploitation. For 
example, because of the highly unsaturated nature of salmon egg oil (iodine 
number of about 220), it is believed that either directly or after slight modi- 
fication, it would be suitable for incorporation into quick-drying paints and 
varnishes. Ihe existing prices for oil, both edible and nonedible, and for 
conmercial lecithin makes the recovery of these two materials from salmon eggs 
a promising possibility. With the fat content of salmon eggs ranging from 11 
to Ik percent on the raw material basis, and with lecithin comprising about one- 
third of the total fat, the possibility of recovering these materials along with 
a high quality protein, seems to warrant further investigation. 

ACKNOWLEDGMENT 

Eugo ft". Nilson of the Service's College Park Fishery Technological Laboratory 
carried out the animal feeding studies for the authors. 

LITERATURE CITED 
ANNO, K. 

1940. J. Aqr. Chem. Soc„, Japan, vol. 16, no. |8|. 
COOK, J. H., and MEH.EN3ACHER, V. C. 

1946. I*>. Enq. Chem., Anal. Ed., vol. 18, no. 785. 
GOSS, W. H. 

1947. Food Industries, vol. i9, no. joe. 
HALPERN, G. R. 

1945. Nature, vol. 155, no. iiO. 
JOKES, G. I. and CARRIGAN, E. J. 

1947. Oept. of Commerce, OTS Report, "Utilization of salmon cannery waste— Part I" Cac-47-i7. 
KOENIG, J., and GROSSFELD, J. 

1913. BIOCHEM. Z., vol. 54, no. 351. 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 15 

FEEDING STUDIES WITH THE GUM OF GRACILLARIA 
CONFERVOIDES AND CARBOXYMETHYLCELLULOSE 

By Hugo W. NilsorT'and Maurice Bender"" 



GRACI LLARIA GUM AND CARBOXYMETHYLCELLULOSE ARE WHOLESOME 
PRODUCTS WHEN FED TO RATS AND MICE IN COMPARATIVELY LARGE QUAN- 
TITIES FOR PERIODS FROM WEANING TO DEATH. 



INTRODUCTION 

Investigation of the possibility of replacement of imported agar with sea- 
weed gums of domestic origin, particularly for use as bacteriological media, 
was a wartime project of the Servicers Fishery Technological Laboratory at 
College Park, Maryland. The gum of Gracillaria confervoides (North Carolina) 
met the specifications of the Pharmacopoeia of the United States XIII (1947) 
for agar. But, it was shown by Lee and Stoloff (1946) that this gum could not 
replace agar as a media for micro-organisms, at least for forensic purposes, 
since it exhibits a comparatively high degree of syneresis. The liquid of 
syneresis permitted spreading of plate cultures so no accurate counts could be 
made. The great majority of samples which were extracted also had such high 
viscosity at temperatures above 45° C. that they were unsuitable for bacteri- 
ological media involving mixing the inoculum with the medium. 

However, the gum from Gracillaria could replace agar from Gelidium in certain 
industrial uses to good advantage. The difficulty in harvesting the seaweed has 
made the cost of material so high that postwar production, at least on any sizable 
scale, has not been continued. The data on feeding studies are reported herewith 
since domestic production may again be undertaken if more efficient harvesting and 
manufacturing processes can be devised. 

Carboxymethylcellulose is made from non-fishery sources. The gum in solution, 
however, showed some initial promise of being used as a glaze on frozen fishery 
products. Unpublished data from this laboratory indicate that the carboxymethylcel- 
lulose film dries out and becomes brittle when fishery products, mostly whole fish 
which have been glazed with the solution, are stored in the freezer. This permits 
dehydration of the products. The experiments did not show sufficient promise to 
recommend this gum as a coating medium. The feeding studies are reported herewith 
since the gum is used in considerable quantities in the food industry. 

ANIMAL FEEDING TESTS 

Rats and mice were allotted to the experiment at about weaning age. They 
were housed individually in wire screen cages fitted with screen floors. Food 
and water were allowed ad libitum . Live weight and food consumption data were 
taken at weekly intervals. Only male rats were used in the tests with Gracillaria 
gum, but both sexes were used in the tests with carboxymethylcellulose. 

Groups were fed the control diet and diets containing 5 and 10 percent 
Gracillaria gum and 5 percent carboxymethylcellulose. The control diet consisted 
of casein, 15; lactalbumin, 5; lard, 15; brewer's yeast, 5; wheat germ, 2; salt 
mixture, U.S.P. XII, No. 2 for vitamin A and D assay, 4; cod liver oil, 2; and 

PHARMACOLOGIST, FISHERY TECHNOLOGICAL LABORATORY, BRANCH OF COMMERCIAL FISHERIES, U. S. FISH 
AND WILDLIFE SERVICE, COLLEGE PARK. MARYLAND. 



16 



COMMERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 




an equal mixture of sucrose and 
and corn starch dextrin, 52 parts 
by weight. The different gums 
were incorporated into this diet 
at the expense of an equal amount 
of the sucrose-dextrin mixture. 

The Gracillaria gum was pur- 
chased on the open market (1944) 
and the two lots which were used 
analyzed, respectively, 13.33 
and 14.73 percent moisture; 1.48 
and 0.86 percent protein (N x 
6 J 25); 7.95 and 5.32 percent ash; 
and 77.24 and 79.09 percent car- 
bohydrates (by difference). This 
gum was produced commercially by 
various companies operating at 
Beaufort, North Carolina. The 
carboxymethylcellulose, low vis- 
cosity type, was supplied by the 
Hercules Powder Company of Wil- 
mington, Delaware. 



WEIGHING A TEST ANIMAL AT THE COLLEGE PARK FISHERY 
TECHNOLOGICAL LABORATORY. 



The initial test with two 
levels of Gracillaria gum was 
carried out for a 10-week period. Comparable data are given for the single level 
of carboxymethylcellulose which was fed. The data in Table 1 are comparable to 
those for algin reported by 
Nilson and Lemon (1942), and 
for agar and Irish moss re- 
ported by Nilson and Schaller 
(1941). The only statisti- 
cally significant differences 
from the controls were great- 
er mean food and water re- 
quirements per unit gain in 
weight for the group fed the 
10 percent level of Graci- 
llaria gum. 



fable 1 — Feeding date with Gracilis 


^rSJ-ff 


ear b oiyae t hy 1 c e 11 ulo s e 
10 rata each 


during tne ten-week 


teat with 


Diet 


daily 


Coefficient 




- Rain la weight 






rsssi. 


~ t « 


ysssi 


«- 


JZ°£* 


11 


Tt 


6 


xiUi liter a 


19 


5 .,6 


Gmcillarlo: 


=:£ 


12 


ss. 


I 


It 


12 

15 


Carb o xyme t by 1 o e 1 lulo s : 
S percent 


3.26 


18 


3.16 


13 


00 tot. 


.«. 


*A significant difference frao contro 


1 according 


to tne Fieher t test. 







OBSERVATIONS ON ANIMAL FEEDING TESTS 

The coefficient, of variation of mean weekly food intake for the group of 
rats fed carboxymethylcellulose is nearly twice that of the groups fed Graci- 
llaria gum. The greater variation apparently was due to what seemed to be di- 
arrhea. The smeary feces were very characteristic but did not seem to be a 
symptom of an injurious process. It was most probably due to the low absorp- 
tion quality of the purified diet. One litter of five rats was allotted to a 
group fed a mixture of 5 percent carboxymethylcellulose and 95 percent ground 
Purina Dog Chow by weight. These rats were fed the diet for a month. They did 
not grow as well as the rats fed the same gum in the purified diet, but the feces 
were firm in texture and well formed. 

Gross necropsy studies of the rats fed the 10 percent level of Gracillaria 
gum at the close of the 10-week test did not reveal any pathology. The remain- 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 



17 



ing animals were fed the diets for a year (the rats fed the 5 percent level of car- 
boxymethylcellulose) , or until they died. The comparative data calculated for the 
10-week period indicate that both gums were wholesome. 

The data in Table 2 show 
that the various animals re- 
ceiving the 5 percent levels 
of Gracillaria gum or car- 
boxymethylcellulose lived as 
long as the respective control 
animals. Those which died and 
upon which a post-morten ex- 
amination could be made did 
not show any gross symptoms 
characteristic of any toxic 
condition. The data in Table 
3 indicate no statistically 
significant differences be- 
tween groups in mean maximum 
weight, mean weekly intake 
of food, or mean weekly in- 
take of water where compar- 
isons are possible. 



Table 2 - Length of life of animal:. ..:-.■.-..■. -wi guni and carboxymsthylcellu. 


lose 


Diet designation 


Length of life in weeks* 


lata: 

Control 


22, 51, 68, 70, 70, 82, 82, 105, 128 


Gracillaria: 
5 percent 


11, 17, 58, 60, 78, 84, 86, 88, 93, 94 


Carboxymethyl cellulose : 


sacrificed after 51 to 57 weeks 


Sice: 
Control 


25, 35, 50, 51, 75 


Carboiymethylcellulose : 
5 percent 


1, 20, 24, 27, 39, 39, 54, 55, 66, 77 


*0nly male rata were used in tests with Gracillaria gum. Both male and female 
were used in tests with carboxymethylcellulose. 


animala 



Table 3 - Feeding data with Gracillaria gum and carboxymethylcellulose during lon^r time tests 








Standard 


Mean 


Mean 


Standard 


Mean 


Standard 




Number 


Mean 


error of 


weekly 


weekly 


error of 


weekly 


error of 


Diet 


of 


maximum 


maximum 


intake 


intake of 


total food 


water 


water 


designation 


animals 


weight 


weight 


of gum 


basal diet 


consumption 


intake 


intake 


Rats: 




grams 


gruni.q 


grams 


grams 


grams 


milliliters 


milliliters 








From weaning to death: 


10 


452 


32 


0.0 


71.4 


3.28 


143.5 


6.96 


Oracillaria; 5 percent •••• 
For one year: 


10 


418 


30 


3.5 


67.4 


2.73 


145.4 


4.15 


















Carboxymethylcellulose, 


10 


404 


19 


3.9 


73.6 


3.20 


_ 


. 


Mice: 


















From about weaning to death: 




















5 


31 


3 


0.0 


18.9 


2.55 


- 


- 


Carboxymethylcellulose, 


10 


32 


3 


1.1 


21.5 


1.69 


- 


- 



The rats fed the 5-percent level of carboxymethylcellulose were sacrificed 
after one year and the principal organs were examined microscopically. The pa- 
thologist found no evidence that the carboxymethylcellulose produced any specific 
uniform change in the heart, liver, kidney, spleen, or gastrointestinal tract. 
There was no evidence of gross pathology when the rats were sacrificed. 



CONCLUSION 

In summary, the data indicate that both the Gracillaria gum and carboxymethyl- 
cellulose are wholesome products when fed to rats and mice in comparatively large 
quantities for periods from weaning to death. 



LITERATURE CITED 



LEE, CHARLES F. AND STOLOFF, LEONARD S. 

1946. STUDIES OF GUM EXTRACTS FROM GRAC 



LLARIA CON- 



FERVOIDES (NORTH CAROLINA). U. S. DEPARTMENT 
OF THE INTERIOR, FISH AND WILDLIFE SERVICE, 
SPECIAL SCIENTIFIC REPORT NO. 37, PP. 1-12. 

NILSON, HUGO W. AND SCHALLER, JOSEPH W. 

1941. NUTRITIVE VALUE OF AGAR AND IRISH MOSS . FOOD 
RESEARCH 6 (NO. 5): PP. 461-69. 



NILSON, HUGO W. ANO LEMON, JAMES M. 

1942. METABOLISM STUOIES WITH ALGIN AND GELATIN. 
U. S. DEPARTMENT OF THE INTERIOR, FISH 
AND WILDLIFE SERVICE, RESEARCH REPORT 
NO. 4: PP. 1-9. 

PHARMACOPOEIA OF THE UNITED STATES 

1947. THIRTEENTH REVISION. MACK PUBLISHING COM- 
PANY, EASTON, PA., P. 721. 



18 



COMMERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 



STUDIES ON ANALYTICAL METHODS OF EXTRACTING VITAMIN A 
AND OIL FROM FISHERY PRODUCTS 

PART IV- EXPERIMENTS ON THE EXTRACTION OF LOW-OIL-CONTENT LIVERS WITH 

ACETONE, ETHYL ETHER, AND PETROLEUM ETHER 

By F. Bruce Sanford and William Clegg* 

This report presents data on further experiments (Sanford and Karrick 1950) 
carried out with a view toward development of improved methods for extracting oil 

and vitamin A from low- 
oil-content fish livers. 
The rockfish ( Sebastodes 
sp. ) livers used in the 
experiments reported 
here were from the same 
batch employed in the 
earlier series. 

Two methods of oil 
extraction were studied: 
the shaking method and 
the soxhlet method. The 
equipment and procedure 
used in the soxhlet method 
were standard, except that powdered pumice was mixed with the liver material in the 
extraction thimble and raw, undried liver was used. All the extraction thimbles 
contained approximately the same weight of liver material (5.4 grams). Details of 
the shaking method were described in the earlier paper. The data are presented in 
Tables 1 to 4. 



Table 1 - The Apparent Concentration of Oil in Varied- 
Weight Samples of Low-Oil-Content Liver Determined By 
Means of the Shaking Method with Acetone as the Solvent!/ 


Approxi- 
mate 
weight 
of liver 
sample 


Apparent concentration of oil in liver 


Replicate sample number 


Average 

of 

replicates 


1 


2 


3 


4 


Grams 

12 

5 

2 


Percent 
14.4 
18.4 
18.4 


Percent 
IS. 6 
18.0 
18.8 


Percent 


Percent 

18.1 
18.9 


Percent 
14.0 
18.2 
18.8 


14.1 
18.4 
19.2 


1/Fifty ml. of acetone was used. The shaking bottle 
had a capacity of 180 ml. 



Table 2 - Data Obtained by Soxhlet Extracting Low-Oil-Content Liver with Acetone and Subsequently 
Purifying the Extractives with Acetone, Ethyl Ether, and Petroleum Ether 


Step Procedure 


Apparent concentration of oil in liver 


Replicate -fmirlfl number 


Average 

of 
replicates 


1 


2 


3 


4 


5 


6 


A Soxhlet extraction for 16 hours 
with acetone 


Percent 
28.6 


Percent 

27.8 


Percent 


Percent 


Percent 
29.4 


Percent 


Percent 
28.4 


28.0 


28.4 


28.0 


Bi/ Acetone purification of ex- 
tractives from step A 


21.1 


20.3 


19.4 


19.4 


21.0 


20.9 


20.4 


C Acetone purification of ex- 
tractives from step B 


20.9 


20.1 


19.3 


19.2 


20.5 


20.5 


20.1 


n§/ Ethyl ether purification of 
extractives from step C 


19.2 


19.0 


18.9 


19.0 


19.1 


19.2 


19.1 


E Ethyl ether purification of 
extractives from step D 


19.0 


18.8 


18.6 


18.9 


18.9 


19.0 


18.9 


EfV Petroleum ether purification of 
extractives from step E 


17.4 


17.2 


17.0 


17.4 


17.4 


17.4 


17. o 


Petroleum ether purification of 
extractives from step F 


17.3 


17.1 


17.0 


17.4 


17.2 


17.3 


17.2 


1/ After the acetone used in the original soxhlet extraction had been evaporated from the extraction 
flask and the weight of extractives determined, the soluble portion of the extractives was re- 
dissolved in added acetone, and the resulting solution was freed of undissolved residue by passing 
the solution through a fritted glass filter funnel. The solvent was then evaporated and the weight 
of extractives determined. The purification steps that follow were carried out in the same manner, 
using the solvent designated in that particular step. The acetone-insoluble residue from step B 
was soluble in hot water. 

2/The residue was soluble in 95-percent ethanol. 



* CHEMISTS, FISHERY TECHNOLOGICAL LABORATORY, SEATTLE. WASHINGTON. 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 



19 



Table 3 - Data Obtained by Soxhlet Extracting Low-Oil-Content Liver with Ethyl Ether and Subsequently 
Purifying the Extractives with Ethyl Ether and Petroleum Ether 


Step 


Procedure 


Apparent concentration of oil in sample 


Replicate sample number 


Average 

of 

replicates 


1 


2 


3 


4 


5 


6 


A 


Soxhlet extraction for 16 hours 
with ethyl ether 


Percent 
18.4 


Percent 


Percent 
18.3 


Percent 
18.0 


Percent 


Percent 


Percent 
18.4 


18.0 


19.0 


18.4 


B 


Ethyl ether purification of ex- 
tractives from step A 


18.2 


17.8 


18.1 


17.8 


18.7 


18.1 


18.1 


C 


Ethyl ether purification of ex- 
tractives from step B 


18.1 


17.8 


18.0 


17.8 


18.6 


18.0 


18.0 


D 


Petroleum ether purification of 
extractives from step C 


17.3 


16.8 


17.2 


17.0 


17.3 


17.0 


17.1 


E 


Petroleum ether purification of 
extractives from step D 


17.2 


16.8 


17.1 


17.0 


17.3 


16.6 


17.0 



It was found that: 

1. In the extraction of low-oil-content liver by means of the 
shaking method and the use of acetone (without dispersing 

or drying agents), relatively more extractives were obtained 
from small-size samples than from those of large size (Table 1). 

2. In the soxhlet extraction of low-oil-content liver for 16 
hours with acetone, certain materials were extracted that 
were not readily soluble in acetone but were readily sol- 
uble in hot water (Table 2, footnote 1). 

3. In soxhlet extracting of low-oil-content liver for 16 hours 
with acetone and then purifying the extractives with acetone, 
ethyl ether, and petroleum ether, certain of the extractives 
that were readily soluble in acetone did not dissolve in ethyl 
ether; and certain of the remaining extractives that were readily 
soluble in ethyl ether did not dissolve in petroleum ether. The 
acetone-soluble residues that were insoluble in ethyl ether dis- 
solved in 95-percent alcohol, as did also the residues that were 
soluble in ethyl ether but insoluble in petroleum ether (Table 2, 
footnote 2) . 



Table 4 - Data Obtained by Soxhlet Extracting Low-Oil-Content Liver with Petroleum Ether and Subsequently 
Purifying the Extractives with Petroleum Ether 


Step 


Procedure 


Apparent concentration of oil in liver 


Replicate sample number 


Average 

of 

replicates 


1 


2 


3 


4 


5 


6 


Ai/ 


Experiment 1 
Soxhlet extraction for 16 hours 
with petroleum ether 


Percent 
3.1 


Percent 
10.6 


Percent 
6.2 


Percent 
2.8 


Percent 
4.1 


Percent 


Percent 
5.6 


6.6 


A 


Experiment 2 
Soxhlet extraction for 16 hours 
with petroleum ether 


12.1 


15.4 


13.8 


9.8 


12.2 


13.7 


12.8 


B 


Petroleum ether purification of 
extractives from step A 


11.9 


15.2 


13.7 


9.5 


12.1 


13.1 


12.6 


C 


Petroleum ether purification of 
extractives from step B 


11.9 


15.3 


13.8 


9.5 


12.2 


13.1 


12.6 


L/Pumice was not mixed with the liver material in the extraction thimble. 



20 



C0M4ERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 



4. Using the soxhlet method, more ethyl ether or petroleum 
ether solubles were obtained when the initial soxhlet ex- 
traction was made with acetone than when it was made with 
ethyl ether or petroleum ether. Likewise, more petroleum- 
ether solubles were obtained when the initial extraction 
was made with ethyl ether than when it was made with pe- 
troleum ether (Tables 2, 3, and 4). 

5. In the soxhlet extraction of low-oil-content liver, using 
petroleum ether as the solvent, the mixing of powdered 
pumice with the liver sample in the extraction thimble 
appeared to aid extraction (Table 4). 

LITERATURE CITED 

SANFORD, F. BRUCE AND KARRI CK, NEVA L. 

1950. STUDIES ON METHODS OF EXTRACTING VITAMIN A AND OIL FROM FISHERY PRODUCTS; 

PART III - EXPERIMENTS ON THE PETROLEUM ETHER EXTRACTION OF LOW-FAT LIVERS 
BY THE SHAKING METHOD. COMMERCIAL FISHERIES REVIEW, VOL. 12, NO. 6, JUNE 
1950, PP. 4-9. 

NOTE : THE OTHER PARTS OF THIS PAPER APPEARED AS FOLLOWS: PART I - " VITAMIN A POTENCIES 
OF OIL FROM GRAYFISH l I VERS OBTAINED BY EXTRACTION WITH PETROLEUM ETHER AND BY COOKING 
WITH WATER," BY D. MIYAUCHI AND F. B. SANFORD, COMMERCIAL FISHERIES REVI_EW, SEPTEMBER 
1947, VOL. 9, NO. 9, AND ALSO AS SEPARATE NO. 186; PART 11 - EXPERIMENTS ON THE SOL- 
VENT EXTRACTION OF LOW-FAT LIVERS, SAME REVIEW, FEBRUARY 1949, VOL. 11, NO. 2, AND ALSO 
AS SEPARATE NO. 224. 




FREEZING AND CANNING KING CRAB 

The techniques used in the preparation and handling of king 
crab are of primary importance in maintaining the quality of the 
canned or frozen product. King crab meat must be processed with 
utmost care to insure the maximum retention of color, flavor, and 
texture. A high quality product can be obtained only if careful 
attention is given to initial phases of handling the king crab, 
such as holding the live crab, butchering, cooking, cooling, re- 
moving the meat, and cleaning. Recommendations are based on ob- 
servations of experimental and commercial packs. 

Additional factors pertaining to packaging of meat for freezing 
and to heat processing are discussed in this publication. 



By John A. Dassow 



—Fishery Leaflet 374 (May 1950) 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 21 

A CHEMICAL EVALUATION OF TUNA-LIVER AND BEEF-LIVER 
MEALS PREPARED BY DIFFERENT METHODS 

By G. Ivor Jones* ana William H. Hoyer** 

ABSTRACT 

MEALS PREPARED FROM BEEF LIVER, ALBACORE TUNA LIVER, AND 
YELLOWFIN TUNA LIVER BY THE PROCESS OF LYOPH I L I ZAT I ON RETAINED 
THE GREATEST AMOUNT OF THE THIAMINE, NIACIN, AND RIBOFLAVIN 
PRESENT IN THE RAW LIVER. 

DEHYDRATION OF THE RAW LIVER BY MEANS OF REPEATED EXTRAC- 
TION WITH ACETONE CAUSED CONSIDERABLE LOSS OF THE THREE VITA- 
MINS STUDIED. ACETONE. HOWEVER, REMOVED MOST OF THE FAT WHICH 
IS EASILY OXIDIZABLE AND, THEREFORE, OBJECTIONABLE WHEN PRESENT 
IN THE FINISHED MEAL. 

VACUUM DRYING OF THE RAW LIVER AT 100° F. PRODUCED DARK- 
COLORED MEALS WHICH RETAINED APPRECIABLE AMOUNTS OF THIAMINE, 
NIACIN, AND RIBOFLAVIN. THIAMINE WAS THE MOST EASILY DESTROYED 
OF THE THREE ViTAMINS INVESTIGATED. MEAL COULD NOT BE SUCCESS- 
FULLY PREPARED FROM ALBACORE TUNA LIVER BY THIS PROCESS BECAUSE 
OF THE PRESENCE OF A LARGE AMOUNT OF FAT. 



INTRODUCTION 

As part of a continuing project on the utilization of wastes of the fish- 
ing and fish-canning industry, a survey of tuna canning plants in the latter 
part of 1948 revealed a large quantity of yellowfin and albacore tuna livers 
available in storage with little market value for production of vitamin A oil. 
Since reduction of the tuna livers to commercial fish meal would yield only the 
minimum potential value of the raw material, it was decided to investigate the 
possibility of preparing high-grade meals by several different methods. The 
meals could then be evaluated as to possible use as supplemental feeding materi- 
als for fish hatcheries, animal and poultry nutrition, or for isolation of valu- 
able chemical substances. In the present report, the preparation of the various 
meals by different methods are discussed in detail, followed by the results of 
proximate chemical analysis and data on three members of the vitamin B complex, 
namely: thiamine, niacin, and riboflavin. Biological evaluation of the raw tuna 
liver in the feeding of hatchery fish will be presented in another report con- 
sidering the nutritional value of many raw natural foods for the propagation of 
hatchery-reared red or sockeye salmon. Comparison of the raw tuna livers and 
meals with that of beef liver was decided upon since the latter is a standard 
article of commerce whose value in nutrition of hatchery fish has been estab- 
lished over the years by numerous investigations. 

EXPERIMENTAL PROCEDURES 

The frozen raw beef liver was obtained from the regular supply of "fluky" 
beef liver used in the production hat chery of the Fish and Wildlife Service at 

* CHEMIST, FISHERY TECHNOLOGICAL LABORATORY, BRANCH OF COMMERCIAL FISHERIES, U. S. FISH 

AND WILDLIFE SERVICE, SEATTLE, WASHINGTON. 

** FISHERY TECHNOLOGIST, PACIFIC OCEANIC FISHERY INVESTIGATIONS, U. S. FISH AND WILDLIFE 
SERVICE. HONOLULU, T. H. 



22 COMMERCIAL FISHERIES REVIEW Vol. 12, No. 11a 

Leavenworth, Washington. The frozen raw tuna livers were furnished through the 
courtesy of the Columbia River Packers Association of Astoria, Oregon. Neither 
the size of the fish nor the geographical location of capture are known, as the 
livers were received in five-gallon tin cans. Upon its receipt in December 1948, 
the frozen liver material was chopped into smaller chunks while still semi-frozen 
and then passed through a meat grinder having a plate with l/8-inch holes. The 
ground material was thoroughly mixed before drawing samples for analyses of the 
raw liver and for the preparation of meal. Samples were packaged in one-gallon 
fibreboard cartons, frozen, and held at 0° F. until used. 

Three types of meals were prepared from the raw liver. The methods used 
included "lyophilization" or vacuum-freeze drying, vacuum drying at 100° F., and 
dehydration by repeated extraction with acetone . It was believed that the prep- 
aration of a meal by vacuum drying of the ground livers while frozen would be 
least destructive of the essential vitamins and other nutritional elements. 
Vacuum drying at 100° F. in a commercial-type steam- jacketed dryer would undoubt- 
edly cause some nutritional loss but would be expected to produce a meal superior 
to those prepared in conventional direct-flame fish-meal dryers. Dehydration by 
repeated extraction with acetone would have the advantage of preparing a meal 
without the application of heat, and in addition reduce the fat content to a 
lower level, which would be especially advantageous with livers having a high fat 
content. However, it is quite possible that this method would remove a portion 
of the water-soluble B complex vitamins Wnich would, of course, be a distinct 
disadvantage. 

PREPARATION OF LYOPHILIZED MEAL : In preparing the lyophilized meal, the 
frozen ground liver samples were thawed at room temperature and then further 
blended and mixed with one-half their volume of distilled water in a Waring 
Blendor. Approximately 600 ml. of this mixture was placed in a 3-liter round- 
bottom distilling flask equipped with a standard- taper glass connector. The 
material was frozen in a thin layer on the inside surface of the flask by alter- 
nately rotating it and then immersing it in a mixture of dry ice and alcohol. 
After the samples were frozen, the flasks were connected to a vacuum system con- 
taining a condenser immersed in a bath consisting of dry ice and alcohol. The 
contents of the flask were dry in approximately 12 hours. The meals prepared by 
this method were vacuum-packed in l/2-pound flat, hermetically-sealed cans and 
held at 0° F. for subsequent analysis. 

PREPARATION OF 100° F. VACUUM-DRIED MEAL : Preparation of a liver meal 
vacuum dried at 100° F. was accomplished by charging 40 to 50 pounds of the 
thawed-ground liver sample into a small Stokes horizontal, rotary-paddle, steam- 
jacketed, vacuum dryer. The charge was maintained at a temperature of 100° F. 
by admitting steam at a pressure of 5 to 10 pounds into the external jacket of 
the dryer and by maintaining a vacuum of 27 inches in the drying chamber. Some 
difficulty was encountered with all three types of livers. Beef liver and yellow- 
fin tuna liver had a tendency for forming into round balls. Midway during the dry- 
ing process it was found expedient to break up these balls of semidried liver in 
order to hasten drying. The difficulties might have been overcome by changing 
the technique but, since our interest was in the meals and not primarily in the 
processing methods, no attempt was made to improve the procedure. 

Albacore livers did not yield a satisfactory product by this method. The 
fat content of these livers is relatively high (about 18 percent fat in raw liver) 
and, under the conditions existing in the dryer, produced a sticky mixture with 
the appearance of grease. Since it did not appear that a satisfactory albacore 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 23 

meal could be readily prepared by this method, this part of the experiment was 
abandoned. 

After drying the beef and yellowfin tuna liver in the Stokes vacuum dryer, 
the residue was finely ground and packed into l/2-pound flat cans, vacuum-sealed, 
and held at 0° F. storage until analyzed. 

PREPARATION OF ACETONE DEHYDRATED MEAL : Dehydration of the thawed, ground, 
raw liver material with acetone was carried out by covering 3 kg. of the liver 
with 12 liters of C. P. acetone in a large glass jar fitted with a plywood cover. 
The mixture was stirred intermittently during the extraction process, which was 
allowed to proceed for 8 hours. At this time, the mixture was allowed to settle 
and the supernatant liquid was siphoned off without disturbing the solid residue. 
The residue was then covered with a second portion of acetone. A total of 3 ex- 
tractions were made. The third acetone extraction appeared to remove only a 
trace of color from the liver solids and it was surmised that the moisture con- 
tent of the residue had by then been reduced to less than 10 percent, which later 
proved to be correct upon analysis. The last traces of acetone were removed from 
the solids by air drying before a fan in a well-ventilated room. When dry, the 
powdered meal was vacuum-packed in tin containers and held at 0° F. during stor- 
age. 

ANALYTICAL DETERMINATIONS : Determination of moisture, total nitrogen, fat, 
and ash on both the raw livers and the prepared meals were made using modifica- 
tions of the A.O.A.C., VI (1945) methods of analysis. These modifications have 
been developed at the Seattle laboratory after many years of study on analytical 
methods applicable to fish products and by-products. The modified procedures are 
as follows: 

Moisture : Weigh 5 to 10 g. of sample into tared aluminum dishes provided 
with covers. For wet material, mix sample with about 20 g. of purified sand 
Place dishes in an air oven at 115° C. for 3i hrs., or in a vacuum oven (l mm. 
mercury or less) at 80° C. for 5 hrs. Cool samples in a desiccator for 1 hr„ 
and weigh. Return samples to oven for 30 min., cool, and weigh to determine if 
weight is constant. 

Total Nitrogen : Weigh 0.5 to 2.5 g. of sample (percent of moisture governs 
amount) into clean, glass cells. Transfer cells to Kjeldahl flasks. Add 6 to 8 
glass beads, 10 g. of anhydrous Na2S0i and a granule of selenium catalyst. Fin- 
ally, add 25 ml. of concentrated l^SO^ and digest the mixture until it becomes 
clear, plus an additional 30 to 60 min. to assure complete digestion. Cool the 
digested mixture and add 180 to 200 ml. of distilled water. Place 25 ml. of 0.5 
N HC1 plus 100 ml. distilled water, plus 4 drops of indicator composed of 0.2- 
percent methyl-red and 0.1-percent methylene-blue in the receiving flask. Add a 
few drops of phenolphthalein indicator to the digest. Pour carefully into the 
tilted flask about 100 ml. of 45-percent NaOH solution. Immediately connect 
flask to the distillation assembly. Distill 150 ml. volume or until "bumping" 
begins. Add an additional 4 drops of the indicator described above to the receiv- 
ing flask to enhance the end point during titration. Total nitrogen multiplied by 
factor 6.25 was used to calculate the value for protein. 

Fat : Weigh 4 to 6 g. of sample into tared alundum thimbles, cover sample 
with a thin layer of cotton and extract for 16 hrs. with 35 ml. of ethyl ether 
in a Bailey-Walker extractor,, 



24 



COMMERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 



Wet materials, such as raw liver, are weighed on several grams of dry pumice 
powder placed in a tared thimble. After weighing, the sample and pumice are 
mixed. The pumice prevents seepage of water through the pores of the thimble. 

The surplus solvent in the extract is distilled off to a low volume, and the 
last traces are removed on a hot plate at low heat. Place flasks in a vacuum oven 
at 80° C. with a vacuum of 24 to 25 in. for 1 hr. Cool in a desiccator for 45 
min. and weigh. 

Ash ; Weigh 3 to 4 g. of sample into tared crucibles. Dry samples in an air 
oven at 80° C. for 2 hrs. Carbonize samples carefully over an open flame, then 
place in an electrically-heated muffle at a temperature of 550° C. for 4 hrs. 
Cool in a desiccator and weigh. 

Thiamine : Determination of this vitamin in the raw and processed samples 
was carried out using the thiochrome method described in Methods of Vitamin Assay 
of The Association of Vitamin Chemists (1947). 

Niacin and Riboflavin : These two vitamins were determined using the micro- 
biological procedures of Roberts and Snell (1946). 

ANALYTICAL RESULTS : The results of the proximate analyses of livers and 
liver meals of beef, albacore tuna, and yellowfin tuna are presented in Table 1. 
The values are averages of 3 or more replicates in all cases except where an 
individual replicate value was at large variance from the others, in which event 
it was discarded. No special difficulty was experienced in making any of the 
determinations. It was noted, however, that in titrating the ammonia distillate 
in the determination of total nitrogen, a sharper end point was obtained when an 
indicator mixture composed of equal parts of 0.2-percent methyl-red and 0.1- 
percent methyl ene-blue in ethanol was used in place of the straight methyl-red 
indicator. The color change of this mixture began as a red-violet at pH 5.2 with 
a change to a grey-blue at pH 5.4 and finally to a green at pH 5.6, which was 
taken as the correct end point . 



Table 1 • 


- Proximate Analyses^/ of Livers and 


Liver Meals of Beef, 




Albacore Tuna,_and Yellowfin Tuna 






Type of Liver 


Condition 


Moisture 


Solids 


Protein 


Fat 


Ash 






1 


A 


A 


_I 


A 


Beef 


Raw 


68.4 


31.6 


18.9 


9.3 


1.3 


Beef 


"Lyophilized" 


4.8 


95.2 


61.2 


18.8 


4.2 


Beef 


Vacuum-dried at 100° F. 


3.5 


96.5 


61.6 


20.5 


4.2 


Beef 


Acetone dehydrated 


6.7 


93.3 


75.4 


4.6 


3.7 


Albacore tuna 


Raw 


60.3 


39.7 


16.6 


18.5 


1.1 


Albacore tuna 


"Lyophilized" 


3.9 


96.1 


39.4 


50.8 


2.5 


Albacore tuna 


Acetone dehydrated 


9.2 


90.8 


73.0 


4.8 


4.4 


Yellowfin tuna 


Raw 


69.8 


30.2 


23.2 


3.1 


1.5 


Yellowfin tuna 


"Lyophilized" 


4.6 


95.4 


72.0 


11.6 


4.6 


Yellowfin tuna 


Vacuum-dried at 100° F. 


2.9 


97.1 


72.3 


10.7 


4.9 


Yellowfin tuna 


Acetone dehydrated 


9.0 


91.0 


79.8 


2.1 


5.0 


1/ Values reporl 


,ed represent an average of 3 to 6 re 


plicates 


. 





The results of the vitamin analyses are presented in Table 2. The thiamine 
values represent an average of duplicate samples. Several confirmatory assays 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 25 

were made in order to check some questionable values. Recovery experiments indi- 
cated that 95 percent recovery could be expected. A standard thiamine sample was 
carried through all the steps of the determination each time that samples were 
assayed. 

DISCUSSION OF RESULTS : Meals prepared by drying in a vacuum at 100° F. had 
the lowest moisture content (Table l) . Drying by lyophilization produced a meal 
nearly as low in moisture content. Undoubtedly, the moisture content of the 
lyophilized meals could have been reduced still further by allowing the process 
to continue for a longer period of time. The acetone-dehydrated and partially- 
defatted meals had a higher moisture level than those prepared by the other two 
methods, but was still under 10 percent moisture. All of these meals had appar- 
ently good storage qualities, except that the fat present, especially in the 
lyophilized albacore tuna-liver meal, oxidized rapidly resulting in a rancid- 
smelling product. This meal darkened rapidly when exposed to air. 

The meals appeared to have no tendency to pick up moisture on exposure to 
air at room temperature nor was there any tendency of the material to mold or to 
spoil. 

The high fat content of lyophilized albacore tuna-liver meal is objectionable 
in that it would reduce the storage life of the finished product and may be unde- 
sirable in the diet of young hatchery fish. However, the recovery of this fat, 
either from the raw liver during meal preparation or by extraction from the dried 
meal, would seem to pose no insurmountable problems, and the oil so obtained might 
even be of considerable economic value. 

In order to compare the effect of the various drying methods on the vitamin 
content of the finished meals, these values were calculated on the moisture-free 
basis and are presented in Table 2. It will be noted that dehydration by means 
of lyophilization caused no significant loss of thiamine in the beef-liver meal. 
The thiamine content of the lyophilized albacore and yellowfin tuna-liver meals 
is approximately twice that present in the raw material when compared on the 
moisture- free basis. These seemingly irreconcilable data can best be explained 
by the fact that the thiamine and other vitamin assays were not performed on 
either the raw material or the several meals until all of the meals had been pre- 
pared. The lyophilized meals were prepared first, early in the 6-month period. 
Thus, the raw-ground liver had been held in frozen storage at 0° F. for about 6 
months before the vitamin determinations were made. The reason for the. values of 
thiamine in the raw material being lower than in the lyophilized meal can best be 
explained by destruction of the vitamin due to liberation or excitation of enzyme 
systems in the raw liver caused by grinding prior to storage. The data in Table 

2 indicate the lyophilized yellowfin tuna-liver meal to be the best source of the 

3 vitamins tested. The liver meals prepared by vacuum drying at 100° F. appear 
to retain niacin and riboflavin without any appreciable destruction, but they do 
sustain a considerable loss of thiamine amounting to approximately 50 percent loss 
in the beef-liver meal and about 66 percent in the yellowfin tuna-liver meal. 

Dehydration of the raw liver by means of acetone causes nearly total loss of 
thiamine in the tuna-liver meals. Acetone extraction also removed one-half to 
two-thirds of the niacin and riboflavin content. This method of meal preparation 
produces a light-colored meal, low in fat, but undoubtedly removes, to some 
degree, members of the vit amin B complex present which, of course, disturbs the 
nutritional balance of the final product. 



26 



COMMERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 



Table 2 - Thi 


amine, Niacin, and Riboflavin Content 


of Livers and 


Liver 


'teals 




of Beef. Albacore Tuna 


, and 


fellowfin Tuna 






Type of Liver 


Condition 


Moist Basis 


Moisture-free Basis 


Thia- 


Nia- 


Ribo- 


Thia- 


Nia- 


Ribo- 






mine 


cin 


flavin 


mine 


cin 


flavin 










per gr 
8.9 






Beef 


Raw 


2.8 


99 


20 


313 


63 


Beef 


"Lyophilized" 


8.6 


365 


87 


9.0 


383 


91 


Beef 


Vacuum-dried at 100°F. 


4.6 


423 


94 


4.8 


438 


97 


Beef 


Acetone dehydrated 


3.5 


77 


65 


3.8 


83 


70 


Albacore tuna 


Raw 


0.3 


48 


16 


0.8 


121 


40 


Albacore tuna 


"Lyophilized" 


1.4 


110 


25 


1.5 


115 


26 


Albacore tuna 


Acetone dehydrated 


0.2 


39 


32 


0.2 


43 


35 


Yellowfin tuna 


Raw 


0.9 


83 


19 


3.0 


275 


63 


Yellowfin tuna 


"Lyophilized" 


5.7 


262 


78 


6.0 


275 


82 


Yellowfin tuna 


Vacuum-dried at 100°F. 


2.0 


269 


67 


2.1 


277 


69 


Yellowfin tuna 


Acetone dehydrated 


0.2 


28 


43 


0.2 


31 


47 



SUMMARY 

Meals of good appearance and apparently good keeping qualities can be pre- 
pared by lyophilization, vacuum drying at 100° F., and by dehydration by repeated 
extraction with acetone. Lyophilization caused the least destruction of nutri- 
tive components. Dehydration by means of acetone resulted in very appreciable 
loss of thiamine, niacin, and riboflavin in the dried meal, but this method pos- 
sessed the advantage of removing most of the- fat which in tuna livers is highly 
susceptible to oxidation. Great difficulty was encountered in attempting to pre- 
pare a meal from albacore livers by vacuum drying at 100° F. due to the large 
amount of fat present. Although the tuna-liver meals do not contain as much 
thiamine, niacin, or riboflavin as does beef-liver meal, it appears possible that 
by furnishing a higher proportion of them in the diet than is customary with beef 
liver, they might supplant the latter in the feeding of hatchery fish. It also 
seems possible that a good-quality tuna-liver meal would possess nutritive factors 
valuable as a vitamin supplement in animal and poultry feeds. 

CONCLUSIONS 

(1) Meals prepared from beef liver, albacore tuna liver, and yellowfin tuna 
liver by the process of lyophilization retain the greatest amount of the thiamine, 
niacin, and riboflavin present in the raw liver. 

(2) Dehydration of the raw liver by means of repeated extraction with acetone 
causes considerable loss of the three vitamins studied. Acetone, however, removes 
most of the fat which was easily oxidizable and, therefore, objectionable when 
present in the finished meal. 



(3) Vacuum drying of the raw liver at 100° F. produces dark-colored meals 
which retain appreciable amounts of thiamine, niacin, and riboflavin. Thiamine is 
the most easily destroyed of the three vitamins investigated. Meal could not be 
successfully prepared from albacore tuna liver by this process because of the 
presence of a large amount of fat. 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 



27 



ACKNOWLEDGEMENT 

The authors acknowledge the assistance of Miss Neva Karrick and Mrs. Mabel 
Edwards of the Seattle Technological Laboratory in carrying out the determina- 
tions of niacin and riboflavin. 

LITERATURE CITED 

ROBERTS, ELIZABETH CUNNINGHAM AND SNELL, ESMOND E. 

1946. AN IMPROVED MEDIUM FOR MICROBIOLOGICAL ASSAYS WITH LACTOBACI LLUS CASE I 
JOUR. BIOL. CHEM. VOL. 163. NO. 2, PP. 499-509. 



THE ASSOCIATION OF OFFICIAL AGRICULTURAL CHEMISTS 

1945. OFFICIAL AND TENTATIVE METHODS OF ANALYSIS. WASHINGTON, 



SIXTH EDITION. 



THE ASSOCIATION OF VITAMIN CHEMISTS, INC. 

1947. METHODS OF VITAMIN ASSAY. INTERSCIENCE PUBLISHERS, 



NEW YORK, N. Y. 




UTILIZATION OF FISHERY BYPROLUCTS IN 

WASHINGTON AND OREGON 
Very little fish scrap is being discarded in the states of 
Washington and Oregon. The small amount not utilized is either 
in an area where the supply is inadequate to support a commercial 
operation, or else the material is of such a nature that it does 
not command a market. Companies have failed because the supply 
of waste has been insufficient,, Others have lost money on the 
production of materials not in demand. Anyone who intends to enter 
the field of byproducts should, therefore, make a thorough survey 
of the source of supply and the market for the finished product. 

The byproducts industry is not static. Changes are taking 
place, and the field is becoming increasingly competitive. Eish 
waste, in earlier years, was thrown away. Later, it was utilized 
only by reduction plants. Now it is in demand for reduction purposes 
and for mink feed and other uses. With few exceptions, the opera- 
tions have not produced appreciable revenue, and many firms have 
operated largely on a marginal basis. For this reason, there is 
a continuing and increasing pressure to find more remunerative 
uses for the waste. The problems to be solved are not easy; but 
with rapid acceleration in technological knowledge and the demands 
of a growing population, further changes are inevitable. 



By F. Bruce Sanford 



—Fishery Leaflet 370 (March 1950) 



28 COMMERCIAL FISHERIES REVIEW Vol. 12, No. 11a 

TECHNICAL NOTE NO. 5-- "PINK YEAST" ISOLATED FROM OYSTERS 
GROWS AT TEMPERATURES BELOW FREEZING 

In certain freezing tests carried out at the Service's College Park Fishery 
Technological Laboratory, several packages of oysters stored at 0° F. for a 
period of one month showed, upon thawing, a decidedly pink-colored liquor and 
pink-to-red spots on the oysters. There had been no signs of discoloration of 
the fresh oysters or liquor when first packaged. "Pink yeast" was suspected as 
being the causative agent for the discoloration. 

Six oysters and a small amount of liquor were taken from each experimental 
lot and were macerated for two or three minutes in a Waring Blendor. A loopful 
of substance was streaked on Sabouraud's agar media in a Petri dish. Gram 
staining in each case revealed a mixed culture of yeast cells and a gram-posi- 
tive rod bacterium. The growth of the bacterium was confluent and rapid, cover- 
ing the yeast colonies. In order to inhibit the growth of the bacterium and 
make it possible to obtain a pure culture of the "pink yeast," one drop of 50 
percent lactic acid was added to 10 ml. of Sabouraud's agar media. A culture 
of "pink yeast" was obtained and an isolated colony from the Sabouraud's agar 
media was transferred to a test tube of Sabouraud's broth media. This culture 
was used for the various inoculations made throughout this study. 

It hardly seemed likely that growth would occur at as low a temperature as 
0° F. ; however, growth did take place in broth tubes at temperatures of 0° F. , 
-14° F., and -30° F. to -35° F. Sabouraud's agar media in plates were also streaked 
with the isolated culture and the plates were stored for one to two months at 0° F. 
Small colorless colonies were noted on the media, after the frost had thawed from 
the inside of the plate. It is felt that colonies of this size could not possibly 
have developed during the half-hour thawing period. Rapid growth with pigment 
formation took place later at room temperature. 

Individual oysters plus liquor were placed in sterile test tubes, inoculated 
with one of the yeast cultures, and stored for one month at 0° F. Samples of oys- 
ters which were not inoculated served as controls. After storage, one frozen oys- 
ter had four large pink colonies on the surface. Diffused pink-colored areas were 
on the surfaces of the other oysters. No visible growth of "pink yeast" was noted 
in the control samples. The colony formation, in particular, was considered good 
proof of growth at 0° F. 

The Inoculated tubes of Sabouraud's broth media which were stored at 0° F. , 
-14° F. , and -30° F. to -35° F. , respectively, all showed small pink colonies in the 
frozen media, which indicated that growth had occurred at these temperatures. 

From the foregoing results, it was concluded that "pink yeast" is capable of 
growing at temperatures of 0° F. to -30° F. 

—Grace McCormack, Bacteriologist, 
Fishery Technological Laboratory, 
College Park, Maryland. 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 



29 



TECHNICAL NOTE NO. 6-VITAMIN-A POTENCIES OF LIVER OILS 
OF BERING SEA COD AND FLOUNDER 

Oil and vitamin-A analyses were made of the livers of certain species of 
Bering Sea cod and flounder. The fish were obtained by the Exploratory Fishing 
and Gear Development Section of the Branch of Commercial Fisheries while con- 
ducting exploratory fishing in the northern Bering Sea area during June-July 1949 
(Ellson, Powell, and Hildebrand 1950). The livers of the following species of 
fish were analyzed: Pacific cod ( Gadus macrocephalus ) , flathead sole or flounder 
( Hippoglossoides robustus and H. elassodon ) , lemon sole or Alaska plaice ( Pleu- 
ronectes quadrituberculatus ) , rock sole or flounder ( Lepidopsetta bilineataT T" 
and yellowf in sole or mud dab ( Limanda aspera ) . 



Table 1 - Data on the Type of Fish, Sex, and Number of Fish Sxh 
Length. Fish Weight, Liver Wei-ht. Oil Coneentratl 



Pacific cod 



Flathead sole 



fellovfin sole 



ngthV 



1/Fish length was the distance from t 
2/2,000 x 2 (1 percent, 1 cm., 328 mm 



17.2 
17.2 
14.5 
17.3 



17.1 



14.2 
15.5 



Fish 
weight 



;d, and Average Vul'ia of the Measurements Obtained on Fish 
in Liver ,_and Vitamin-A lotency of Liver Oil 



1.87 
2.06 



0.262 
0.329 



0.026 
0.024 



tip of the nose to the fork of the tail 
, isopropanol, whole oil). 



7,600 
18,100 



14,400 
35,800 



10,200 
7,800 



10,600 
20,200 



The livers were analyzed by the "snaking method," using ethyl ether as the 
solvent (Anonymous 1947). The data are reported in Tables 1 and 2. 

The livers of the flathead sole, lemon sole, rock sole, and yellowf in sole 
were, on the average, less than an ounce in weight and contained only a small 
amount of oil, which was of a relatively low vitamin-A potency. Such livers are 
of only marginal value. 

Oil concentrations and vitamin-A potencies of the cod livers reported here 
are similar to those of livers taken commercially in 1947 from fish caught in the 
Bering Sea off the Alaska Peninsula (Sanford and Nilson 1949). Northern Bering 
Sea cod livers may, therefore, be of potential commercial value. This conclusion, 
however, is contingent upon the price of vitamin A rising at least to the 1947 
level. 



Table 2 - Data on the Lowest and Highest Values Obtained in the Measurement of Fish Length, Fish Weight, Liver 
Weight, 011 Concentration in Liver, and Vitamin-A Potency of Liver Oil 



Species 
of fish 



Pacific cod 



Flathead sole 



Lemon sole 



Yellowfin sole 



Sex 

of fish 



Male 
Female 



Male 
Female 



Male 
Female 



Male 
Female 



length^ 



Centi- 
meters 



High 



Fish 
weight 



,010 
,240 



782 

652 



366 

580 



High 



5,840 
7,82b 



894 

1,750 



910 
2,100 



542 
1,245 



Liver 
weight 



High 



210 
288 



Oil concentration 
in liver 



20.2 
4.2 



High 



34.8 
17.2 



1/Fish length was the distance from the tip of the nose to the fork of the tail. 
2/2,000 x e (1 percent, 1 cm., 328 mmu. , isopropanol, whole oil). 



Vitamin-A potency 
of liver oil 



er gr^ni2/ 
1,500 
1,100 



6,120 
7,600 



865 
,840 



8,280 
1,740 



HiSl. 



opec" units, 

per grarn ^/ 

18,400 

73,100 



26,700 
93,600 



102,000 
42,300 



30 



COMMERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 



LITERATURE CITED 

ANONYMOUS 

1947. PRELIMINARY PROCEDURES FOR THE ANALYSIS OF VITAMIN A IN FISHERY BYPRODUCTS. 
COMMERCIAL FISHERIES REVIEW, VOL. 9, NO. 1, (jANUARy) PP. 40-2. 

ELLSON, J. G., POWELL, DONALD E., AND HILOEBRAND, HENRY H. 

1950. EXPLORATORY FISHING EXPEDITION TO THE NORTHERN BERING SEA IN JUNE AND JULY 1949. 
U. S. FISH AND WILDLIFE SERVICE FISHERY LEAFLET 369. 

SANFORD, F. B. AND NILSON, H. W. 

1949. VITAMIN A AND D POTENCIES OF THE LIVER OIL OF PACIFIC COD. COMMERCIAL FISHERIES 
REVIEW, VOL. 11, NO. 5, (MAY) PP. 13-5. 

— F. Bruce Sanford, Chemist, 
John A. Dassow, Chemist, 
Ernest F. Dietrich, Laboratory Aide , 
Fishery Technological Laboratory, 
Seattle, Washington. 




INFORMATDN SOURCES FOR STUDENTS OF 

COMMERCIAL FISHERIES 
Fishery Leaflet 362, Information Sources for Students of Com- 
mercial Fisheries , is a 20-page publication designed to show the 
student various means of obtaining information on the commercial 
fisheries of North America. It is not meant to be a complete bib- 
liography — only the principal contributions or bibliographies are 
listed. 

References in this publication are listed under the following 
major categories: Agar; byproducts} canning; cookery; directories; 
employment; fish and fisheries; freezing; gear; libraries; marketing; 
oils, rancidity, antioxidants; salting; sanitation; smoking; spoil- 
age; statistics; technical journals; trade journals; visual aids; 
and vitamin oils. Items which are recommended as basic sources 
are indicated. 



By R. Paul Elliott 



—Fishery Leaflet 362 (January 1950) 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 31 

TECHNICAL NOTE NO. 7-RESULTS OF SOME TESTS WITH 
FROZEN LOBSTERS AND LOBSTER MEAT 

INTRODUCTION 

Very little information is available regarding the freezing characteristics of 
lobsters and lobster meat. Although the quantity available for freezing would un- 
doubtedly be quite limited due to the heavy demand for live lobsters, it may be de- 
sired at times to freeze this product on a small scale. This is evident by the in- 
quiries on freezing of lobsters received by the Fish and Wildlife Service from locker 
plant operators, and manufacturers and owners of home freezers. 

With this in mind, a limited study of the storage of frozen lobsters and lob- 
ster meat was made. Since the work was restricted to only a comparatively small 
number of samples held at only one storage temperature, it should not be construed 
that the results are conclusive. Possibly other methods of preparation and lower 
storage temperatures would alter the findings considerably. 

PREPARATION OF SAMPLES 

Live lobsters and freshly-cooked lobster meat were obtained and prepared for 
the tests in Gloucester, Mass. Five lots were prepared for freezing, as follows: 

1. Whole live lobsters. These are designated later in this 
report as the "uncooked" sample. 

2. Whole cooked lobsters. These were live lobsters boiled 
for 16 minutes in salted water 11 tablespoon of salt to 
1 quart of water). 

3. Whole cooked lobsters. Similar to (2), which were frozen 
in blocks of ice after one month of storage at 0° F. 

4. Cooked lobster meat packed without liquid in half-pound 
tin cans and hermetically sealed. 

5. Cooked lobster meat packed in lg percent brine in half- 
pound tin cans and hermetically sealed. 

All samples were frozen in circulating brine at a temperature of approximately 
0° F. , followed by storage in a room at the same temperature. The whole lobsters 
were given an ice glaze to retard desiccation. 

It had been planned to freeze several cooked lobsters in blocks of ice at the 
time the samples were being prepared in order to ascertain whether a minimum of des- 
iccation during storage would prevent changes in the texture of the meat. Because 
of certain difficulties this was not done at the time of freezing but was done a 
month later (Lot No. 3). The samples were kept ice-glazed during this interval. 

All of the lots were shipped with dry ice in an insulated container to the 
Service's Fishery Technological Laboratory in College Park, Md. , and were received 
in a frozen condition. The whole lobsters were then reglazed and packaged individ- 
ually in heavy metal foil wrappers. All samples were held in storage at 0° F. 



32 



COMMERCIAL FISHERIES REVIEW 



Vol. 12, No. 11a 



At monthly intervals, samples from each lot were removed from frozen storage 
and allowed to thaw at room temperature. Those that were uncooked were thawed, 
then boiled in salted water for 16 minutes, and cooled before being tested. The 
meat was picked from the whole lobsters and cut into pieces for palatability tests. 
The meat from fresh-cooked live lobsters was used as controls. AL1 samples were 
designated by a code unknown to the judges at the time of testing. Members of the 
laboratory staff, accustomed to making taste tests, served as judges. Scores were 
based on the appearance, flavor, and texture of the lobster meat. A score of 85 
or over is considered satisfactory. 

RESULTS AND DISCUSSION 

The palatability scores obtained in the tests are given in Table 1. The fro- 
zen uncooked lobsters consistently received a satisfactory and relatively high score 

at each examination during 
the six-month period. The 
flavor and texture of the 
meat after cooking was 
generally considered to 
be quite satisfactory. 

The frozen cooked 
lobsters received variable 
scores from month to month 
and in general were not 
satisfactory. The meat 
was often spongy and wa- 
tery, and was not at all 
like that of fresh-cooked 
lobsters. The meat of 
the cooked lobsters fro- 
zen in blocks of ice 
showed no improvement 
over that of the cooked 
ones held in the usual 
manner. 

Neither of the lot 3 
of frozen picked meat 
stored too well. The 
meat that was frozen without added liquid (dry pack) failed to receive an accept- 
able score during any month of the storage period. The flavor of the meat was ob- 
jectionable and the texture was described as watery and spongy. The meat frozen 
with added liquid (brine pack) received somewhat higher scores but in general it 
could hardly be considered satisfactory either. It is doubtful if this pack has 
very much in its favor over the dry-packed product. 

In all lots, the claw meat was sometimes found to have somewhat of an off fla- 
vor, even though the body meat was all right. 



Table 1 - Monthly Palatability Scores for Whole 
Lobsters and Picked Lobster Meat Stored at 0° F. 


Experimental 

condition of 

samp_le 


Lot 

numbei 1 


Palatability Score-^ 


Storage Period (Months) 


1 


2 


3 


4 


5 


6 


Frozen whole lobsters 


1 
2 

3 


91 
74 

79 


87 

88 

81 


91 
84 

88 
67 


93 
72 

81 


89 
82 

79 

96 


93 
83 

83 

88 






Cooked (frozen in 


Frozen lobster meat 


4 
5 


79 
80 
83 


84 
89 
86 


81 
86 
91 


78 

86 

89 ' 


68 
83 
92 


73 

82 
88 






l/The palatability score was calculated as follows: 
The meat was scored on the basis of 1 to 10 points 
each for appearance, flavor and texture. The flavor 
score was doubled in order to give additional weight 
to this factor. The mean as a percent of these 
scores resulted in the value reported in the table. 
A score of 85 or over is considered satisfactory. 



Considerable variation was found in the scores for the fresh controls, 
may have been due to the manner in which the live lobsters were handled. 



This 



While the frozen uncooked whole lobsters received the highest palatability 
scores, there is one other factor that must be considered. After cooking the whole 



November 1950 - Supplement COMMERCIAL FISHERIES REVIEW 



33 



lobster, the meat was found to stick very tightly to the shell and was difficult 
to remove without breaking it into small pieces. This may or may not be objection- 
able, depending upon the attitude of the consumer, since the meat is very often cut 
into smaller pieces before being used . 

Note: a united states patent has recently been granted which deals with the freezing of lob- 
sters. IT IS claimed that the difficulties encountered in removing the meat from the 
shell of lobsters frozen alive or raw and then cooked may be overcome by a brief heat 
treatment prior to freezing. this treatment consists of an immersion of the lobster 
in boiling water for an interval of not less than 15 seconds nor more than 5 minutes 
depending on the shell thickness. the heating period should be only of sufficient 
duration to produce a cooking of the surface of the meat next to the shell but not to 
cook the meat bei ow the surface. a heating period of about 1-1/2 minutes is said to 
be sufficient for a one pound lobster. after heating, the lobster is cooled and quick 
frozen (u. s. patent no. 2,501,655 frozen lobster method, ptd . march 28, 1950). 

~S. R. Pottinger, Chemist, 

Fishery Technological Laboratory, 
College Park, Maryland. 





TECHNOLOGICAL SECTION 






Branch 


of Commercial Fisheries, U. S. Fish and Wildlife Service 
Department of the Interior 




Name 
Harold E. Crowther 
Frank T. Piskur 


Washington, D. C. 
Title 
Chief, Technological Sectior 
Asst. Chief, " " 


Room Number 
3350 
3352 


Telephone 
Republic 1820 
Elt. 4745 


Field Activities 
Fishery Refrigeration 

Name Title Address 
James M. Lemon Technologist Fishery Technological Laboratory 
P. 0. Box 128 
College Park, Md. 


Telephone 
Warfield 
5800 


Laboratories 
Location 
East Boston 28, Mass 


Address 
. Fishery Technological Laboratory 
Lockwood Basin 
61 Sumner Street 


In Charge 
Joseph F. Puncochar, 
Bacteriologist 


Telephone 
7-4307 


College Park, Md. 


Fishery Technological Laboratory 
P. 0. Box 128 


Clifford F. Evers, 
Technologist 


Warfield 
5800 


Ketchikan, Alaska 


Fishery Products Laboratory 
Box 647 


John A. Dassow, 
Technologist 


540 


Seattle 2, Wash. 


Fishery Technological Laboratory 
2725 Montlake Boulevard 


Maurice E. Stansby, 
Chemist 


East 
0586 



F. T. Piskur 



Technological Editors for this Issue: 

H. E. Crowther J. M. Lemon 

***** 

Illustrator — Gustaf T. Sundstrom 
Compositors — Jean Zalevsky, Carolyn Wood, Betty Coakley 



***** 



Photograph credits : Cover - Nos. 1 and 2 and p. 16 — G-. T. Sundstrom; Nos. 3 
and 4 — anonymous. 



-Duplicating Section, Washington, D. C. 8579» 



TUNA TROLLING IN THE LINE ISLANDS IN THE LATE SPRING OF 191. 



3 9088 01018 1204 



In the normal course of scouting for suitable purse-seine schools of tuna, the John R. Manning . 
one of the Service's Pacific Oceanic Fishery Investigations research vessels, trolled 5 to 7 lines as 
a secondary and incidental procedure during a two-month survey in the Line Islands during the late 
spring of 1950. The ind' cations of possible good production of tunas with surface trolling and the 

experience gained in surface trolling methods for 
Line Island tunasare discussed in Fishery Leaf, et ~;1 , 
Tuna Trolling in tne Line Islands in the Late Spring 
of 1950 . 

Thl3 32-page leaflet points out that good sur- 
face trolling was not unexpected in the Line Islands 
(Kingman Reef, Palmyra, Washington, Fanning, and 
Christmas), but the John R. Manning was unprepared 
both in quantity and strength of trolling gear for 
the size of fish encountered end for the number of 
hours devoted to trolling. It is the consensus of 
of servers aboard the research vessel that a standard 
trolling boat, familiar with the area end properly 
rigged, would heve been able to double, et the very 
^^^^^ least, the catch of the John R. Manning . 



The vessel trolled a total of 385^hours, catch- 
ing 882 yellowf in ( Heothunnus Eacropteru3 ) weighing 
29,319 pounds. Thus, the average weight for all 
yellowfin was 33. 9 pounds. A total of 178 wahoo or 
ono ( Acanthocybium solandri ) were taken, estimated at 5.888 pounds. In addition, a small number of 
skipjack ( Katsuwonus pelHnis ) and miscellaneous fish were trolled, including rainbow runners ( Elagatis 
blpinnulatus ) and barracuda ( Sphyraenldae ) . 




Included in the leaflet is a description or the gear and rigging :isei, and trolling operations 
and results as well as tables giving detailed catch data. 

Copies of Fishery Leaflet 35I are available free upon request from the Division of Information, 
U. S. Fisn and Wildlife Service, Washington 25, D. C. 




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