摘要:

Blood samples were analyzed for lactic acid from 66 troll caught chinook salmon after from zero to 103/4 hours of rest. Fish were held in a live box aboard a trolling vessel. During the course of the experiment 22 individuals died. Analysis of these data indicate a general response of blood lactic acid comparable with results of other experiments. The typical response is a gradual increase of blood lactic acid to high levels in the third and fourth hours, followed by a general decline. Death is strongly associated with high blood lactic acid. The level of lactic acid response is not significantly increased with more than 10 minutes of vigorous exercise nor is it significantly affected by the size of the fish within the ranges sampled in this experiment. Mortality rate is estimated at 71% with 95 percent binomial confidence limits of 40% and 86%.

ISSN:0706-652X    

DOI:10.1139/f59-011

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

A representative section of the Lake Winnipeg whitefish fishery was studied during seven summers. The average size of whitefish in samples numbering from 100 to 3,500 fish yearly varied with time and place, but trends were absent. Ages of whitefish in commercial catches, determined by scale reading, revealed three main age groups each year during six summers. Fishing success varied during 7 years and showed no indication of a trend toward better or worse fishing. Some parts of the fishing ground are but lightly exploited. Temperature changes in inshore water masses affected catches in some fishing gear.

ISSN:0706-652X    

DOI:10.1139/f59-012

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Sizes attained by several species of fish inhabiting both sea and fresh waters suggest that the larger size of the marine form is due to the higher osmotic content of the medium. This theory was tested experimentally by comparing fresh and saltwater growth of juvenile coho, sockeye and chum salmon and adult goldfish. Such factors as temperature and food were rigidly controlled. In general, the salmonids (coho, chum or sockeye underyearlings) grew more rapidly in saline than in fresh water. Adult goldfish did not show any significant difference in weight increase.

ISSN:0706-652X    

DOI:10.1139/f59-013

出版商:NRC Research Press    

年代:1959

数据来源: NRC

摘要:

Investigations of a Lake Winnipeg winter fishery for sauger,Stizostedion canadense, and yellow walleye,S.vitreum vitreum, during January and February each year revealed some significant changes in average size for two species as the season progressed, and from year to year. Average weight based on 50 to 1600 fish approximated 0.5 lb for sauger and 0.7 for walleye in most areas. Fishing success declined during the study period. A sample of the sauger catch revealed mainly age-groups III, IV and V. Fish catches appeared unrelated to either water temperatures or dissolved oxygen. Increased use of nylon nets had no apparent effect on annual production.

ISSN:0706-652X    

DOI:10.1139/f59-014

出版商:NRC Research Press    

年代:1959

数据来源: NRC