scholarly journals Recent Trend in Variability of Chum Salmon Stock and its Potential Mechanism in Hokkaido, Japan

2021 ◽  
Author(s):  
Hirokazu Urabe ◽  
Hayato Saneyoshi ◽  
Makoto Hatakeyama
1982 ◽  
Vol 60 (6) ◽  
pp. 1463-1469 ◽  
Author(s):  
Terry D. Beacham

Significant regional and annual variability in fecundity of coho salmon (Oncorhynchus kisutch) and chum salmon (O. keta) in British Columbia was detected during this investigation. A Kodiak Island (Alaska) coho salmon stock was more fecund than southern stocks in British Columbia and Washington. Fecundity ranged from 2450 to 2850 eggs per female at 53.6 cm postorbital–hypural length for Vancouver Island stocks to over 4400 eggs per female for a Kodiak Island stock at the same length. Chum stocks on Vancouver Island and the Queen Charlotte Islands generally had fecundities less than 3200 eggs per female at 58.8 cm postorbital–hypural length, whereas chum of equal lengths in mainland British Columbia stocks ranged from 3200 to 3450 eggs per female. Older chum and coho were usually more fecund than younger ones, but this difference could be accounted for by differences in mean length-at-age, fecundity being related to body size.


1983 ◽  
Vol 40 (11) ◽  
pp. 1880-1886 ◽  
Author(s):  
B. A. McCarl ◽  
R. B. Rettig

Regression studies of salmon stock-recruitment relations require a priori assumptions concerning the nature of stock variability as influenced by smolt populations. Such assumptions can lead to biased estimates of the relationships of smolts to the production of adult salmon. This paper utilizes a statistical method which allows the data to determine the interrelationship of smolts and adult production mean and variability without imposing a priori restrictions on the form of such. The estimation process yields two estimated relationships — one explaining the effect of hatchery releases on expected adult production and another explaining the effects of the hatchery releases on the standard deviation of adult production. Application of this model suggests that the standard deviation of adult production increases with the square of the number of seaward migrants both for Hokkaido chum salmon (Oncorhynchus keta) and for Oregon coho salmon (O. kisutch) and that incorrect inferences may have been obtained about density dependence by other authors because of the imposed a priori assumptions and/or data adequacy.


2018 ◽  
Vol 84 (5) ◽  
pp. 924-924
Author(s):  
YASUYUKI MIYAKOSHI
Keyword(s):  

Author(s):  
Melanie K. T. Takarangi ◽  
Deryn Strange

When people are told that their negative memories are worse than other people’s, do they later remember those events differently? We asked participants to recall a recent negative memory then, 24 h later, we gave some participants feedback about the emotional impact of their event – stating it was more or less negative compared to other people’s experiences. One week later, participants recalled the event again. We predicted that if feedback affected how participants remembered their negative experiences, their ratings of the memory’s characteristics should change over time. That is, when participants are told that their negative event is extremely negative, their memories should be more vivid, recollected strongly, and remembered from a personal perspective, compared to participants in the other conditions. Our results provide support for this hypothesis. We suggest that external feedback might be a potential mechanism in the relationship between negative memories and psychological well-being.


2016 ◽  
Author(s):  
Rosemary Bland ◽  
Corina Chivu ◽  
Kieran Jefferson ◽  
Donald MacDonald ◽  
Gulnaz Iqbal ◽  
...  

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