瀬戸内海産ホンダワラ科藻類の分布について

Distributional Study of Sargassaceae of the Seto Inland Sea

Sadada Ken

Fujiyama Toraya

Inumaru Sunao

広島大学水畜産学部紀要

Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University

1. 1954年から1963年にわたって瀬戸内海とその近辺約60の地点で採集されたホンダワラ科藻類の分類を行ない,21種2変種4品種を確認した。
2. これにこれまでの報告の結果を加えて瀬戸内海におけるホンダワラ科の32種2変種4品種の藻類の分布を示した。
3. 瀬戸内海を紀伊水道から播磨灘までの海域,備讃瀬戸から芸予諸島にいたる海域,安芸灘,広島湾を含む海域,伊予灘,周防灘およびその近辺の海域の4つの海域に分け,各藻類の各海域における出現率を検討して各藻類の分布特性を調べた。
4. その結果,ヒジキ,クソタレモク,オオバモク,イソモク,トゲモク,ホソバモク,スギモクは外洋的性格のより強い種であることがわかった。また,ヒジキの一品種,マメタワラ,ヤツマタモク,カラクサモク,アカモク,ノコギリモク,ヨレモク,ナノリソ,フシスジモク,オオトラノオ,エンドウモクは内湾的性格のより強い種であることがわかった。
5. ヒジキの一品種は,外洋的性格の強い原種が内湾において適応を示した形態ではないかと考えられる。また,アカモクの一品種であるクソタレモクは,内湾的性格の強い原種が外洋性の強い海域において適応を示したものではないかと考えられる。

1. Twenty one species, 2 varieties and 4 forms of Sargassaceae were identified in algal samples collected from 60 stations in the Seto Inland Sea and the adjacent waters between 1954 and 1963.

2. The distributional characteristics of these algae are investigated from ecological standpoint in relation to the influence of the offshore water. For this purpose we distinguished the Seto Inland Sea into 4 regions, 2 of which are outer regions and the others inner regions, and the characteristics of each alga are discussed by calculating the percentages of occurrence, R, for each region.
R = s/S×100
where s: number of stations where the alga was collected,
S: total number of collecting stations in the region.

3. As the result of this investigation we may state clearly that Hijikia fusiforme, Sargassum horneri f. furcatodentatum, S. ringgoldianum, S. hemiphyllum, S. micracanthum, S. angustifolium, and Coccophora langsdorfi prefer outer regions which are under the influence of the offshore water, and that H. fusiforme f. clavigerum, S. piluliferum, S. tortile, S. turneri, S. confusum, S. thunbergii f. swatzianum and S. yendoi foster better in inner regions where the influence of the offshore water is rather weak or negligible.

4. The distributions of 32 species, 2 varieties and 2 forms of the same family in the Seto Inland Sea are described on the basis of our collection and the data already reported by other authors.

5. It is hypothetically concluded that while H. fusiforme prefers outer regions, its form f. clavigerum is apt to grow better in inner regions, and also that S. horneri f. furcatodentatum is a form adapted to outer regions though its original species prefers inner regions.

Fishing industry. Fisheries [ 660 ]

jpn

広島大学水畜産学部

[ISSN] 0440-8756

[NCID] AN00213563

[NAID] 40003288858