Efficiency of Natural Propagation of the Pink Salmon (Oncorhynchus gorbuscha) in McClinton Creek, Masset Inlet, B.C.

1948 ◽  
Vol 7b (5) ◽  
pp. 224-236 ◽  
Author(s):  
A. L. Pritchard

Through the medium of specially-designed counting fences, records have been maintained of the adult pink salmon, Oncorhynchus gorbuscha, spawning in McClinton creek, Masset inlet, B.C. from 1930 to 1942, of the eggs available for deposition each season and of the fry resulting from these eggs. A loss of 76.2 to 93.1 per cent of the potential egg deposition occurs between the time of upstream spawning migration and the egress of the fry to sea. This mortality is assigned to a number of factors, some of which are briefly discussed. Within certain limits and under reasonably uniform climatic conditions smaller egg depositions provide greater efficiencies of hatch (percentage relationship of numbers of fry migrants to potential egg deposition). There thus appears a tendency toward rebuilding the run, herein termed "resilience," and believed to be closely bound up with the relationship between the fish and its physical and biological environment.


1966 ◽  
Vol 23 (5) ◽  
pp. 747-756 ◽  
Author(s):  
Roger E. Pearson

Mean numbers of circuli on scales of juvenile pink salmon collected along the coast of North America in 1964 increased from 1.7 on June 23 to 17.4 on September 10. On scales of adults collected from the eastern North Pacific Ocean from 1962 to 1965, mean numbers of circuli ranged from 24.1 on January 23 (1964) to 46.9 on September 2 (1962). The fork length at time of scale formation was approximately 60 mm. Mean fork length increased with the total number of circuli. The relationship of fork length to number of scale circuli showed some variation between stocks. The winter ring was present or was being formed on the majority of scales taken in late January. The development of the annulus varied considerably among individual fish.







1961 ◽  
Vol 18 (3) ◽  
pp. 337-348 ◽  
Author(s):  
Donald E. Bevan

A study of spawning ground surveys for pink salmon (Oncorhynchus gorbuscha) was made in two streams on Kodiak Island. An experimental design is described which permits replication of observers' counts of spawning salmon. The variance in an observer's estimate was found to be proportionate to the size of the estimate. The experiments indicated that an observer will detect differences in population size of plus or minus 50%. The relationship between counts of one observer and another changes within different streams, but within each river the observations of one observer were correlated with those of another. The results of the experiments are summarized in recommendations for aerial surveys of spawning salmon.



1937 ◽  
Vol 3 (5) ◽  
pp. 403-416 ◽  
Author(s):  
A. L. Pritchard

The spawning runs of pink salmon to McClinton creek, Masset inlet, B.C., in 1930, 1932, 1934, and 1936, differed little in time of appearance of the first migrant and disappearance of the last. The period occupied for the main portion of each run to reach the spawning beds depended chiefly upon rainfall and freshet conditions. Males occurred in greater numbers at the beginning of every run but a subsequent increased influx of females eventually brought about equality of the sexes in two seasons. In the third the males predominated slightly, and in the fourth the females. The average length and weight of males are consistently greater than those for females in the same year. Usually a significant increase in length occurred in both sexes from the commencement to the end of the run. In some cases a similar gain in weight was demonstrated but in others it was apparently masked by loss in weight consequent upon fasting during the spawning migration. The number of eggs per female in a given year increases with increase in length and weight.



2019 ◽  
pp. 42-44
Author(s):  
I.V. GUSAROV ◽  
V.A. OSTAPENKO ◽  
T.V. NOVIKOVА

Впервые в мире создана популяция зубров на территории 60 градусов северной широты. В новых климатических условиях разведения и сохранения зубров определены и проанализированы факторы существования вида на севере Европейской части РФ. Выявлены признаки, динамика численности, которые являются составной частью системы, предназначенной для управления биоразнообразием. Интродукция, являясь процессом введения в экосистему нехарактерных для нее видов, может усиливать изменения биоценозов как положительно, так и отрицательно. Насколько быстро и успешно проходит процесс адаптации заселенного вида, и усматривается его влияние на окружающую среду зависит дальнейшее существование зубров и в целом биоразнообразия. В статье обсуждаются вопросы взаимоотношения зубров с другими видами копытных и хозяйственной деятельностью человека, а также дальнейшим использованием зубров в сельскохозяйственном производстве. Пластичность зубров, выявление изменений и их анализ при вселении видов в новые условия обитания необходимы не только для определения развития или деградации биоценозов и в целом экосистемы, но и прогноза социально-экономических последствий интродукции как одного из методов сохранения редких и исчезающих видов фауны.For the first time in the world, a bison population has been created in an area of 60 degrees north latitude. In the new climatic conditions of breeding and preservation of bison, the factors of the species existence in the north of the European part of the Russian Federation are identified and analyzed. The signs, dynamics of abundance, which are an integral part of the system designed to manage biodiversity are identified, since the preservation of biological diversity on the planet is one of the main problems of our time. Introduction, being the process of introducing non-typical species into an ecosystem, can enhance changes in biocenoses, both positively and negatively. The question posing sounds especially when it comes to such a large hoofed animal as the European bison. How quickly and successfully the process of adaptation of the universe takes place and its environmental impact is seen depends on the continued existence of bison and biodiversity in general. The article discusses the relationship of bison with other types of ungulates and human activities, as well as the further use of bison in agricultural production. How these issues will be resolved positively depends on the future of these animals. Thus, the plasticity of bison, the identification of changes and their analysis, with the introduction of species into new habitat conditions is necessary not only to determine the development or degradation of biocenoses and the ecosystem as a whole, but also to predict the socio-economic consequences due to the introduction as one of the methods of preserving rare and endangered species of fauna.





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