@article{oai:soar-ir.repo.nii.ac.jp:00016457,
 author = {倉沢,  秀夫},
 journal = {信州大学理学部付属諏訪臨湖実験所報告},
 month = {Mar},
 note = {(1) Lake Suwa is one of the lakes which have the highest landing yield of commercial fishes per unit area in Japan. It is the shallow eutrophic lake located at the altitnde 759 m in Nagano Prefecture in Central Japan. It has a maximum depth of 6.5 m, a mean depth of 4.1 m, a surface area of 13.3 km3 and a volume of 0.06 km2. In the recent twenty years the lake has been eutrophicating year and year, and water pollntion was had the tendency of progressing. So that the awful water bloom of blue-green algae has come to appear every summer. (2) Annual changes in monthly fish yields, money amounts for them and units of price of each fish kind were showed from 1932 to 1940, before the II World War and from 1950 to 1980, the postwar. The highest value of monthly yields of total fishes during the past 40 years above mentioned, was 312 ton in Mar. 1934, that of fishes only (except molluscs and shrimps) 80 tons in Apr. 1975, molluscs 294 tons in Mar. 1934 and shrimps 12.5 tons in Nov. 1939. (3) In monthly changes in fish yields during the past 40 years, the seasonal patterns of total fishes, fishes only, molluscs, Hypomesus, Gnathopogon ･ Psendorasbora, Viviparidae and Unionidae were seen as typically bimodal with the spring and fall maxima, Carassius and Gobiidae with the spring and summer ones, and shrimps with the summer and winter ones. The seasonal patterns of Cyprinus, Sarcocheilichthys and Tribolodon were showed as unimodal with the early spring maximum, Oncorhynchus, Pseudogobio and Parasilurus with the late spring one, Anguilla and Zacco with the early summer one, and Plecoglossus, Pseudoperilamps ･ Rhodeus and Cobitidae with the summer one. In the pre-war, fishes only, Hypomesus, Carassius and shrimps showed unimodal patterns with the winter maximum, and Cobitidae did bimodal with the spring and summer maxima, and Tribolodon with the spring and winter ones. (4) The largest values of monthly yields of each kind of all fishes during the past 40 years indicated the range from 0.23 to 72.8 tons, and the decreasing order of them were as follows: Hypomesus > Pseudoperilamps ･ Rhodeus > Carassius > Cyprinus > Zacco > Gnathopogon ･ Pseudorasbora > Gobiidae > Parasilurus > Cobitidae > Anguilla > Sarcocheilichthys > Tribolodon > Oncorhynchus > Precoglossus > Pseudogobio ; those of molluscs did the range from 22.3 to 1,287.1 tons; the decreasing order of them being Unionidae > Viviparidae > Corbiculidae. (5) The highest value of monthly money amounts for total fish yields was 43,473 yen in Dec. 1932, the pre-war and 30,462 × 10 3 yen in Dec. 1975, the post-war. The largest values of each kind of fishes showed the range from 17 to 37,498 yen in the pre-war, and from 26 × 10 3 to 25,559 × 10 3 yen in the post-war, the decreasing order of them were as follows; Hypomesus > Carassius > Cyprinus > Shrimps > Viviparidae > Pseudoperilamps ･ Rhodeus > Cobitidae > Gnathopogon ･ Pseudorasbora> Sarcocheilichthys > Corbiculidae > Parasilurus > Gobiidae > Anguilla > Unionidae > Zacco > Plecoglossus > Oncorhynchus > Tribolodon. (6) In the highest value of monthly unit of price of each fish kind, the largest was 5.28 yen of Plecoglossus and the smallest 0.17 yen of Viviparidae in the pre-war; the former being 750 yen of Anguilla, the latter 0.10 yen of viviparidae in 1950's; 1,633 yen of Hypomesus and 133 yen of Unionidae in 1960's; 2,818 yen of shrimps and 250 yen of Unionidae in 1970's respectively. (7) In monthly changes of unit price of each fish kind during the past 40 years, the seasonal patterns of Oncorhynchus and Zacco were seen as bimodal with the spring and fall maxima, Parasilurus with the summer and winter ones, Gobiidae with the spring and winter ones. On the other hand those of Zacco and Cyprinus were showed as unimodal with spring muximum; Plecoglossus, Pseudoperilamps ･ Rhodeus, Viviparidae with the summer one, Hypomesus with the fall one, and Gnathopogon ･ Pseudorasbora, Sarcocheilichthys, Tribolodon, Carassius, Corbiculidae and Unionidae with the winter one., Article, 信州大学理学部付属諏訪臨湖実験所報告 5: 1-105(1984)},
 pages = {1--105},
 title = {諏訪湖の漁獲量およびその出荷金額高の経年季節変化(1932～1940年間，1950～1980年間) -諏訪湖漁業協同組合および其の他の資料による-},
 volume = {5},
 year = {1984}
}