摘要:

From analyses of 22,087 vertebral counts, embracing 12 consecutive year-classes and five contiguous areas along the west coast of Vancouver island, it is concluded that more than one population of herring is present, that each area, with the possible exception of one, has an essentially separate run, and that mixture or interchange between areas is generally limited. A significant interaction between mean counts for year-classes and areas might be interpreted as indicating mixing between areas in certain of the year-classes, thus qualifying the general conclusion. Comparison with the conclusions drawn from tagging shows essential agreement. However, the latter method of study demonstrates that mixture between areas does take place and is considerably more extensive than might be anticipated by the term "limited". Furthermore, it reveals that mixture of fish from different areas takes place within the school, i.e., within the sampling unit, and therefore cannot be demonstrated by analyses of mean vertebral counts.

ISSN:0706-652X    

DOI:10.1139/f47-032

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Concentrations of nitrite required to prevent or retard the formation of trimethylamine in cod fillets stored at 3 °C. are much less than those required to inhibit bacterial growth on the fish under the same conditions.This is not the result of the nitrite having a selective inhibitory action on the growth of bacteria that reduce trimethylamine oxide.

ISSN:0706-652X    

DOI:10.1139/f47-033

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

The bacterium,Pseudomonas putrefaciens, has been isolated from fresh and frozen cod fillets, and appears to be new for marine fish and a significant contributor towards their spoilage.

ISSN:0706-652X    

DOI:10.1139/f47-034

出版商:NRC Research Press    

年代:1949

数据来源: NRC

摘要:

Underyearling salmon in a circular pond of moving water at 20–25 °C. swam during the day and rested on the bottom at night. Before feeding they translocated actively upstream in rapid shallow water and in all directions in slow deep water. During feeding they held position in slow water, but made short excursions to seize food. After feeding, most moved into rapid, shallow water, the largest into the most rapid water.Translocating salmon usually went upstream and swam faster in more rapid water so that the rate of translocation remained constant. The rate of translocation increased with the size of the fish, more than doubling from 3 to 4 cm. in length.While steady illumination caused the salmon to swim up in the water from the bottom, a sudden change in light intensity when they were swimming, as by an object moving against the sky, caused them to swim quickly from shallow to deep water.Eels translocated upstream regularly only in the more rapid water, the swimming rate increasing with current rate. Eels 7 cm. long translocated almost twice as rapidly as salmon 3.5 cm. long. Eels burrowed in the gravel in bright daylight, came out in the evening and translocated rapidly even at night when the salmon were resting.

ISSN:0706-652X    

DOI:10.1139/f47-035

出版商:NRC Research Press    

年代:1949

数据来源: NRC