目次

事業概要
Ⅰ章

事業の目的、内容並びに経過概要・・・・・・・・・・・・・・・・・・・・・・・１

1）目的・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１
2）事業内容・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１3）事業計画・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・２
4) 事業の経過概要・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・３
Ⅱ章

支笏湖をとりまく環境の現状と変遷・・・・・・・・・・・・・・・・・・・・・・７

1）自然環境・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・７（1）地理・地形・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・７（2）地質・火山活動・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・８（3）気候・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１０（4）植生・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１２2）社会環境・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１３（1）人口・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１３（2）土地利用・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１５（3）上下水道整備・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１６（4）道路開発・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１８（5）産業・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１９3）水環境・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・２１（1）水質・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・２１（2）底質・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・２６（3）透明度の変化・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・２７(4) 水位変動・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・２８
Ⅲ章

支笏湖の生物とヒメマス・・・・・・・・・・・・・・・・・・・・・・・・・・３１1）生息する生物・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・３１（1）魚類とその他の大型動物・・・・・・・・・・・・・・・・・・・・・・・・・・３１（2）底生生物相と一般生態・・・・・・・・・・・・・・・・・・・・・・・・・・・３８（3）プランクトン相と一般生態・・・・・・・・・・・・・・・・・・・・・・・・・４０(4) 水草相と分布・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・４７2）ヒメマスの利用・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・５１（1）増殖の歴史的経緯（支笏湖のヒメマスの増殖）・・・・・・・・・・・・・・・・５１（2）支笏湖のヒメマス資源の利用を巡って・・・・・・・・・・・・・・・・・・・・６０（3）支笏湖のヒメマス釣りの変遷・・・・・・・・・・・・・・・・・・・・・・・・６５

Ⅳ章

北海道内のヒメマスの移殖・・・・・・・・・・・・・・・・・・・・・・・・・６９1）支笏湖へのヒメマスの移殖・・・・・・・・・・・・・・・・・・・・・・・・・・６９2）生態・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・７５
3）資源量・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・８３4）増養殖量・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・８９5）種卵の移動と魚病の防疫・・・・・・・・・・・・・・・・・・・・・・・・・・・９５6）遊漁の状況・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１１５
Ⅴ章

ヒメマスと自然環境保全－支笏湖を例として－・・・・・・・・・・・・・・・１２１

Ⅵ章

我が国におけるヒメマスの増養殖・・・・・・・・・・・・・・・・・・・・・１２３1）ヒメマスとベニザケ・・・・・・・・・・・・・・・・・・・・・・・・・・・・１２３2）ヒメマスの故郷・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１３２3）ヒメマスの移殖の足取り・・・・・・・・・・・・・・・・・・・・・・・・・・１３７4）ヒメマス資源の活用（新資源造成事業）・・・・・・・・・・・・・・・・・・・１４３5）ヒメマスの池中飼育に関する研究・・・・・・・・・・・・・・・・・・・・・・１５４
Ⅶ章

総合考察・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１５７

補遺
菅沼のヒメマス・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１６５
文献一覧・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・・１８３
資料

付録ＣＤ－ＲＯＭ

図表一覧

図Ⅱ-1

支笏湖周辺······················································································································ 7

図Ⅱ-2

支笏カルデラ火山活動 ·································································································· 9

図Ⅱ-3

月別平均気温の比較 ···································································································· 10

図Ⅱ-4

月別降水量の比較 ·········································································································11図Ⅱ-5

支笏湖周辺の植生区分図····························································································· 12

図Ⅱ-6

支笏湖周辺の町別人口の推移····················································································· 14

図Ⅱ-7

千歳市の人口の推移 ···································································································· 14

図Ⅱ-8

支笏湖畔地区簡易水道の総排水量と有収水量の推移·············································· 16

図Ⅱ-9支笏湖畔特定環境保全公共下水道の総処理水量及び有収水量の推移··················· 17

図Ⅱ-10

支笏湖周辺の主要道路と冬季閉鎖区間 ··································································· 18

図Ⅱ-11

千歳市の産業別人口··································································································· 20

図Ⅱ-12

支笏地域観光客入込数の推移··················································································· 20

図Ⅱ-13

支笏湖表層における月別平均水温（1970 年～1996 年） ······································ 21

図Ⅱ-14

支笏湖における水温の鉛直分布（1961 年）··························································· 22

図Ⅱ-15

支笏湖（ポロピナイ沖）における 60m 以浅の水温鉛直分布（1972 年～1974 年）··································································· 22

図Ⅱ-16

公共用水域水質調査地点図······················································································· 23

図Ⅱ-17

COD の経年変化（1979 年～2002 年、表層の平均） ············································ 23

図Ⅱ-18

支笏湖の表層における全窒素の経年変化 ······························································· 24

図Ⅱ-19

結氷する支笏湖 ·········································································································· 25

図Ⅱ-20

支笏湖における透明度の変化 5 地点（St.1、St.2、St.3、St.5、St.6）の平均······ 27

図Ⅱ-21

支笏湖水位観測所における 1973 年～2000 年の水位変動 ····································· 28

図Ⅲ-1

アメマスの鰓耙数と鰓耙間隔比················································································· 33

図Ⅲ-2

調査刺し網で採集された魚類の CPUE の経年変化·················································· 33

図Ⅲ-3

最近の支笏湖におけるヒメマスの釣獲数、回帰親魚数
および調査網 CPUE の経年変化 ··············································· 34

図Ⅲ-4

2002 年 6～8 月に支笏湖注入河川で採集された魚類··············································· 35

図Ⅲ-51999 年、美笛川と支笏湖に生息するニジマスおよびブラウントラウトの餌生物の季節変化························ 36

図Ⅲ-6

支笏湖における甲殻類プランクトン 4 種の出現個体数の年変動 ·························· 44

図Ⅲ-7

支笏湖における甲殻類プランクトン 4 種の出現個体数の季節変動······················· 45

図Ⅲ-8

支笏湖におけるヒメマスの採卵数と分与卵数（1898 年～1924 年）····················· 52

図Ⅳ-1

支笏湖のヒメマス親魚捕獲数の変動 ········································································· 84

図Ⅳ-2

洞爺湖のヒメマス漁獲量の変動················································································· 85

図Ⅳ-3

阿寒パンケ湖のヒメマス漁獲量の変動 ····································································· 86図Ⅳ-4

支笏湖のヒメマス採卵数と稚魚放流数の変動·························································· 90

図Ⅳ-5

洞爺湖のヒメマス稚魚放流数の変動 ········································································· 91

図Ⅳ-6

パンケトーのヒメマス稚魚放流数の変動 ································································· 91

図Ⅳ-7 ··········································································································································· 96
図Ⅳ-8 ··········································································································································· 97
図Ⅳ-9

支笏湖におけるヒメマスのミズカビ病発症率及び治癒再生魚出現率の状況 ····· 100

図Ⅳ-10

ベニザケ（4 歳） ····································································································· 104

図Ⅵ-1

ベニザケの分布域 ······································································································ 125

図Ⅵ-2

1978-1987 年、支笏湖ヒメマス流下魚の降湖時期 ················································· 126

図Ⅵ-3

支笏湖ヒメマス流下魚 ······························································································ 126

図Ⅵ-4

支笏湖におけるヒメマス放流数と回帰数の経年変化············································ 127

図Ⅵ-5

阿寒湖とチミケップ湖の位置関係 ··········································································· 134

図Ⅵ-6

支笏湖、十和田湖、中禅寺湖からの移出卵の経年変化 ········································ 140

図Ⅵ-7

北海道におけるベニザケ親魚の河川内捕獲数の年変化 ········································ 144

図Ⅵ-8

安平川に回帰した支笏湖ヒメマス由来のベニザケ親魚 ········································ 146

補遺図 1

最初のヒメマス移植当時の菅沼・丸沼・大尻沼の図 ········································ 162

補遺図 2

上沼（清水沼）のボート前とその左方清水流れ込みの方向を望む ················· 163

補遺図 3

ヒメマスの成熟親魚······························································································· 170

補遺図 41973 年 11 月 30 日上沼の流れ込み左岸寄りに群がる産卵ヒメマス ················ 171

補遺図 5

菅沼ヒメマスの産卵河川清水の流れ込み···························································· 172

補遺図 6

産卵後半年生残ヒメマス ······················································································· 173

補遺図 7

産卵後半年生残ヒメマス ······················································································· 174

表Ⅱ-1

支笏洞爺国立公園の特別地域、普通地域の内訳······················································ 15

表Ⅱ-2

支笏湖周辺域の土地利用状況····················································································· 15

表Ⅲ-1

支笏湖で確認された魚類····························································································· 32

表Ⅲ-2

特別採捕事業におけるヒメマスの採捕数 ································································· 61

表Ⅲ-3

任意の釣獲票によるヒメマス（チップ）の釣獲数·················································· 66

表Ⅳ-1

阿寒湖から支笏湖への「カバチェッポ」卵の移殖実績 ·········································· 69

表Ⅳ-2

サケ、サクラマス稚魚の放流実績 ············································································· 70

表Ⅳ-31902 年（明治 35 年）以降、支笏湖に搬入された魚種 ··········································· 73

表Ⅳ-4

北海道の湖沼産ヒメマスの生産量 ············································································· 86

表Ⅳ-5

北海道における湖沼別ヒメマスの遊漁券の発券数·················································116

表Ⅵ-1

阿寒湖とチミケップ湖の湖盆形態の比較 ······························································· 133

補遺表 1

菅沼へ放流されたヒメマス・ベニザケ一覧（1913～1963）····························· 165

補遺表 2

淡水区水研日光支所が菅沼へ試験放流したヒメマス一覧（1965～1991） ····· 166

補遺表 3

1967～1976 年 菅沼における成長期ヒメマスの体長分布（雄雌こみ） ········ 167

補遺表 4

1973～1978 年の菅沼ヒメマス産卵親魚（雄雌こみ）の体長頻度分布と抱卵数 ········································· 168

補遺表 5

菅沼・中禅寺湖・湯ノ湖と制限食飼育群のヒメマス魚体各部位の相対成長 ··················································· 169

補遺表 6付表 11973 年 7 月と 11 月の菅沼（上沼湖心）の水質 ················································· 175
支笏湖のヒメマスの親魚捕獲数、採卵数、放流数、分与卵数(1898～1945 年)·································· A-1

付表 2

支笏湖のヒメマスの親魚捕獲数、採卵数、放流放流、分与卵数（1946～1985 年）························· A-3

付表 3

明治後期から昭和前期までのヒメマスおよびベニザケ卵の移殖まとめ（1900 年～1938 年までの期間） ········ A-5

付表 4

明治後期から昭和前期までのワカサギ卵の移殖まとめ（1900 年～1938 年までの期間） ········ A-7

付表 5

摩周湖産ヒメマス卵の移植まとめ（1971 年～1975 年まで）······························· A-8