摘要:

Goldfish (Carassius auratus L.) and coho salmon fry (Oncorhynchus kisutchWalbaum) were acclimatized to temperatures of 20 °C. and 3 °C. respectively. The fish were placed, one at a time, once a day, for ten days, in a rotating annular chamber and the cruising speed was found. Then various fins were removed and the fish were given ten more trials. The mean cruising speeds before and after clipping were compared. The clipped fish suffered no loss in ability to swim at a constant rate. The data suggest that, for fish of a given weight and length, cruising speed is slightly improved by clipping. Any increased mortality in marked fish is due to loss of stability and control rather than loss in ability to swim steadily.

ISSN:0706-652X    

DOI:10.1139/f50-002

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The brown discolouration which occurs on heating (120 °C., 1 hr.) white flesh of fish was found to be due largely to reactions of the Maillard type. Browning did not occur in leached flesh unless compounds containing a free aldehyde group, or a potential free aldehyde group, were added. Addition of amino acids and substances which did not possess a free aldehyde group did not occasion browning in leached flesh. Discolouration was inhibited by bisulphite and hydroxylamine and slightly by acids, but it was not affected by heating in vacuo, by storing whole fish in ice prior to heating or by addition of metal ions.

ISSN:0706-652X    

DOI:10.1139/f50-003

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

Lakelse lake is a temperate, eutrophic lake situated on the eastern margin of the Coast Range mountains. For five years physical and chemical studies of this lake have been conducted as part of the Skeena River Salmon Investigation. Its area of 5.2 square miles (14.2 sq. km.) and mean depth of 24 feet (7.9 m.) provide a relatively small volume of water which is subject to considerable circulation from heavy winds sweeping in from the Pacific coast. Summer thermal stratification is varied and irregular, resulting in a proportionately large and unstable epilimnion. Except for a single bottom depression, oxygen concentrations remain at a high level throughout the year.During four months of the year the lake is ice covered. Large snow and ice fields provide an excellent reservoir for stream flow.Among the Skeena river lakes Lakelse is one of the most productive of sockeye salmon. Their survival does not appear to be limited directly by physical or chemical factors.

ISSN:0706-652X    

DOI:10.1139/f50-004

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The number of young sockeye migrating seaward from Lakelse lake, B.C., was 557,000 (1946) and 373,000 (1947). From seeding estimates in the parent years per cent survivals of 1.1 and 0.4 have been calculated.Stomach analyses of 623 squawfish caught by gill nets in the late spring and summer months (1944–1947) show an average fish content of 83% by volume. Of this total fish content sockeye constitute 31%. The heavy losses in young sockeye could be attributed to the feeding of predacious fish and variation in sockeye survival may be a result of fluctuations in the abundance of "buffer" species.

ISSN:0706-652X    

DOI:10.1139/f50-005

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

It was observed that a reduction in storage temperature from 2.8 °C. to − 0.3 °C. approximately doubled the keeping time for haddock and cod fillets as judged by the development of trimethylamine. This reduction of 3° in the region of the freezing point added to the keeping time of commercial fillets approximately the same number of days as a reduction of 22° (from 25 °C. to 2.8 °C.) at a higher temperature range.Somewhat similar results were obtained by reducing the storage temperature of whole, gutted codfish.

ISSN:0706-652X    

DOI:10.1139/f50-006

出版商:NRC Research Press    

年代:1950

数据来源: NRC

摘要:

The four major components of salmon viscera were tested as food for young trout. It was found that there is a growth-promoting factor in the roe and the milt which is not contained appreciably in beef liver, salmon liver, or salmon digestive tract. It was found also that this factor could be extracted from the roe both by water and by methyl alcohol, but not by petroleum ether.

ISSN:0706-652X    

DOI:10.1139/f50-007

出版商:NRC Research Press    

年代:1950

数据来源: NRC