摘要:

Extracts and enzymic hydrolysates were prepared from cod, haddock, salmon, whale, seal, beef and pork livers. Extraction was carried out with water at pH 5; enzymic hydrolysis was effected by papain at pH 5.5 and at 65 °C. followed by pancreatin at pH 7.5 and at 50 °c. The proper digestion times were established. Extracts, as well as hydrolysates, were concentrated by distillationin vacuoto the consistency of syrup and then dried at a low temperaturein vacuo. The preparations were analysed for a large number of inorganic and organic constituents. Comparisons of the results for preparations from fish livers with corresponding products from mammalian livers lead to the conclusion that fish livers are useful raw materials for the production of extracts and enzymic hydrolysates for use in foods or in medicinal preparations.

ISSN:0706-652X    

DOI:10.1139/f55-033

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The muscle of a sturgeon taken off Nova Scotia contained no trimethylamine oxide. The electrophoretic pattern of the water-soluble proteins indicates at least 10 non-dialysable components in the extract, two of which have weak positive mobilities.

ISSN:0706-652X    

DOI:10.1139/f55-034

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

If absolute recruitment (R) and natural mortality rate (q) are both presumed constant in each of two or more periods of stabilized fishing, it is shown thati = q + (1/R)iC, whereiis instantaneous total mortality rate andCis catch in numbers. The relationship yields approximate estimates ofRandqunder semi-stable conditions if "average referableC" is related to apparenti, the former derived from catch data and the latter from age-composition data for post-recruited age-groups. In the herring population, in which recruitment takes place mostly at age III but is spread from ages I to IV, the average of the catch of yearsxandx + 1 is referable to apparentiat ages IV to V in yearx + 2, at ages V to VI in yearx + 3,etc. Whenqincreases with advancing age, it is shown thatRis most accurately estimated from data for ages IV to V;qis slightly overestimated at ages IV to V and underestimated at ages VI to VII and VII to VIII. From data for periods of approximate stability in the lower east coast of Vancouver Island population, averageRis estimated at about 500 million fish per year; averageqappears to increase with age, ranging from about 0.4 at ages IV to V to about 0.85 at ages VII to VIII. For a recent period of stabilized intensive fishing, a rough estimate of the average initial size of the fishable stock, based on age-composition and catch data, agrees well with that estimated by another method. For populations along the west coast of Vancouver Island,qalso appears to increase with advancing age;Ris estimated at about 400 million fish. In an appendix it is shown that a method of estimatingqfrom age-composition and effort data gives unsatisfactory results because effort expended in herring fishing is not proportional to rate of fishing of the stock.

ISSN:0706-652X    

DOI:10.1139/f55-035

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

In 1942 a pollution survey was made of Humber Arm, Bay of Islands, and Exploits River, Notre Dame Bay, Newfoundland, where pulp and paper mills are situated.Fresh water from the Humber River affects the salinity of the water in Humber Arm mainly to a depth of about 10 metres. The salinities and sulphates increased from the surface to the bottom while the temperature and dissolved oxygen decreased. No sulphite was detected. It was concluded that the operations of the mill have no injurious effects on fish life in Humber Arm.On the Exploits River the dissolved oxygen was decreased by the mill effluents, and sulphite was detected in appreciable quantities, but neither of these effects was sufficient to harm fish life.

ISSN:0706-652X    

DOI:10.1139/f55-036

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Analysis of vertebral counts of 28,097 cod (Gadus callariasL.) in 184 samples from the Canadian mainland coast demonstrates some segregation of inshore and offshore populations and little mixing between the cod on various sections of the coast. Four populations are recognized in the Gulf of St. Lawrence. Three offshore populations and at least four inshore populations are also recognized along the south coast of Nova Scotia. Seasonal migrations northward in summer and southward in winter are indicated by changes in vertebral numbers. Small cod (less than 21/2 lb.) exhibit less variability in vertebral number than larger ones, suggesting increased mixing with growth.

ISSN:0706-652X    

DOI:10.1139/f55-037

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The rate of oxygen supply to salmon eggs incubating in a stream bed depends on the oxygen concentration in the groundwater and the rate of seepage through the redd. Wickett (1954) devised a simple field method of both sampling the groundwater for the determination of its dissolved oxygen content and measuring the seepage rate, using one tool, a standpipe. The theory of seepage is outlined to show the factors governing the velocity of flow through a redd. Alternative ways of measuring this velocity were examined; the best one is a modification of Wickett's procedure using a similar standpipe. A new field procedure for measuring the oxygen concentration and groundwater seepage rate in a stream bed is recommended.

ISSN:0706-652X    

DOI:10.1139/f55-038

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The scale/body relationship for Kamloops trout is very close to direct proportion for fish larger than 4.5 cm. fork length. The resultant plot on a double logarithmic grid is linear with a slope not significantly different from 1.00 (45°). Calculations of lengths of trout from scales at ages previous to that of capture can be made on the basis of simple proportion in two ways, (1) by use of a constant slope (45°) on a double logarithmic plot, or (2) by use of a constant zero-zero intercept on an arithmetic plot.Growth of the scales of the young is characterized by relatively rapid increase from time of scale formation, 3.5 cm. fork length up to 4.5 cm. At about 4.5 cm. fork length there is a sharp break (inflection) in the relative growth curve toward isometric growth of scales and body. Reliable estimates of the length of trout may be obtained from scales alone, using the diameter of the first circulus of the scale, the slopes and inflection of the relative scale/body plot and total diameter of the scale at time of capture.Marked Kamloops trout of known size were released in 1953. Subsequent recaptures both in 1953 and 1954 substantiated the accuracy of the method of estimating lengths of trout at ages previous to that of capture.Observations on the steelhead trout,Salmo gairdneri gairdneri, and on the coastal cutthroat trout,Salmo clarki clarki, suggest that an isometric scale/body relationship may exist among those species also.

ISSN:0706-652X    

DOI:10.1139/f55-039

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The sea sturgeon,Acipenser oxyrhynchusMitchill, occurs in the western north Atlantic Ocean from Canadian waters south to the Gulf of Mexico. Specimens taken from eastern Florida to Quebec are assigned to the typical subspeciesoxyrhynchus, while 2 specimens from off Mississippi are here described as the new subspeciesde sotoi. The latter differs in having a longer head, longer pectoral fins, strongly developed scutes of distinctive shape and an unusually long spleen.

ISSN:0706-652X    

DOI:10.1139/f55-040

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

The distribution, bathymetrical occurrence and spawning periods of three widely distributed arctic-boreal species of barnacles,Balanus balanoides,B.balanusandB.crenatus, are given from Ungava Bay, Frobisher Bay, Cumberland Sound and Hudson Strait.

ISSN:0706-652X    

DOI:10.1139/f55-041

出版商:NRC Research Press    

年代:1955

数据来源: NRC

摘要:

Material for this study was gathered by field parties of the Fisheries Research Board in the summers of 1944, 1945 and 1946. A description of the subspecies is given, based on measurements of 26 specimens. The distribution ofStenodusin Great Slave Lake, and in northern North America is outlined. The rate of growth was determined from an examination of scale samples from 298 fish, and it was found that the inconnu has a rapid growth rate, even in this highly oligotrophic lake. Inconnu spawn mainly in the rivers which enter Great Slave Lake from the Mackenzie Lowlands. The upstream run apparently occupies most of the summer but evidence is presented which indicates a major movement in late August. The post-spawning, downstream run takes place in late September or early October. Residents take advantage of it to put up inconnu for winter dog feed. The food of young inconnu in the spawning streams was found to be mainly invertebrates, whereas in Great Slave Lake the species is almost entirely piscivorous. A list of parasites is given, among whichTriaenophorus crassusis considered of major importance. The rate of infestation with the larvae of this worm is high—88 per cent of 49 fish examined, at a rate of 64 cysts per 100 pounds. At present the major use of the inconnu is in the domestic fishery where it serves local trappers, and others, as dog feed.

ISSN:0706-652X    

DOI:10.1139/f55-042

出版商:NRC Research Press    

年代:1955

数据来源: NRC