摘要:

The results obtained have shown that, in general, a germicidal ice which retards bacterial, spoilage of fish is much more effective when the pH of the flesh is low than when it approaches the neutral point. Of the ices used those containing 0.1% sodium nitrite, 0.01 to 0.02% sulphanilamide, 0.01% sulphathiazole and 0.067% chloramine B plus 0.067% sodium benzoate were quite effective in delaying spoilage. Ices containing chloramine B, chloramine T, No-Bac, Rivanol, penicillin, Roccal and Emulsept retarded spoilage only slightly or not at all.

ISSN:0706-652X    

DOI:10.1139/f47-016

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Cultures ofPseudomonasisolated from marine sources grew in sea water and died out in fresh water. Cultures ofPseudomonasisolated from non-marine sources died out in sea water and grew in fresh water. The addition of small amounts of peptone interfered with this inhibiting action of both sea water and fresh water.

ISSN:0706-652X    

DOI:10.1139/f47-017

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

When goldfish are placed in a rotating annular chamber of which the outer wall is glass, they can be induced to swim steadily at a rate which varies with the temperature when the water is aerated. When the subjects have been in each case previously acclimated to the experimental temperature the best performance is attained at temperatures from 20 to 30 °C., the highest temperature to which goldfish can be acclimated being 41 °C. Subjects acclimated to a variety of experimental temperatures gave curves of performance in relation to temperature which were unique for each level of acclimation.

ISSN:0706-652X    

DOI:10.1139/f47-018

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

The lake trout (Cristivomer namaycush) is the principal fish of Great Bear lake. The largest populations were found in semi-isolated bays, with smaller populations in the open lake on one hand and in river mouths and marshy areas on the other. The trout grow very slowly; by three years they are just over three inches (7.6 cm.) long and weigh one ounce (28 g.). A weight of one pound (0.45 kg.) is achieved in their ninth year and two pounds in their fourteenth year. Maturity is reached in from 13 to 17 years; the rate of growth in weight increases after maturity. Mature fish appear to spawn only every second or third year. Spawning begins about the middle of August. The young trout spend their first four summers in shallow water near shore. The adults feed on all food sources in the lake,—plankton, bottom organisms, fish and terrestrial insects. Fish preparing to spawn have pale flesh; others have orange to red flesh. There is some evidence of two morphologically distinct groups, probably resulting from environmental differences. A list of the parasites of the trout is given. A detailed analysis of the incidence of cysts ofTriaenophorus crassusindicates that adult trout remain in one locality throughout life.

ISSN:0706-652X    

DOI:10.1139/f47-019

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

Scale samples and length and weight measurements of 281 pike from Great Bear lake, Great Slave lake, lake Athabaska and Lesser Slave lake have been used to calculate the rate of growth. A comparison with the growth rate of pike from Waskesiu lake, Saskatchewan, and lakes in Wisconsin shows that, in general, the rate varies with north latitude. The northern fish live five years longer but never attain as large a size. It is shown that the relationship between length and weight is independent of the rate of growth. Males and females grow at the same rate but females appear to live longer than males.

ISSN:0706-652X    

DOI:10.1139/f47-020

出版商:NRC Research Press    

年代:1948

数据来源: NRC

摘要:

not available

ISSN:0706-652X    

DOI:10.1139/f47-021

出版商:NRC Research Press    

年代:1948

数据来源: NRC