Annual Changes in the Number of Licenses Issued by Each Fishing Method and Catches of Ayu in the Jinzu and Shou Rivers.
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Accession number;01A0448124
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| Title;Annual Changes in the Number of Licenses Issued by Each Fishing Method and Catches of Ayu in the Jinzu and Shou Rivers. |
| Author;
TAGO YASUHIKO
(Toyama Prefect. Fish. Exp. Stn.)
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Journal Title;Suisan Zoshoku
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Journal Code:Y0285A
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ISSN:0371-4217
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VOL.49;NO.1;PAGE.117-120(2001)
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| Figure&Table&Reference;FIG.5, REF.12 |
| Pub. Country;Japan |
| Language;Japanese |
| Abstract;The number of fly-fishing licenses issued for ayu, Plecoglossus altivelis, which are operated only in the large pools of the Jinzu and Shou Rivers, decreased markedly from 1980 to 1998. On the other hand, the total number of recreational fishermen for ayu, and the number of licenses issued for two types of net and tomozuri which are used mainly at runs, increased during the period. These appeared to well correspond to a decrease in the number of large pools in both rivers. Scale of the juvenile release in recent years expanded several times as high as in 1978 in both rivers. However, the catch in the Jinzu River decreased one half or one thirds, and that only scarcely increased in the Shou River during the period. The relationship between annual catch (y) of ayu and number of licenses (x) for fly-fishing in the Jinzu River during 1988 to 1998 fitted a linear regression equation as expressed by y=-88.3+0.0827x (r=0.706, p<0.01), suggesting that the decrease in ayu resources is closely related to the changes in reach types of river such as loss of larger pools. (author abst.) |
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