原著論文　ORIGINAL PAPER

北部九州岩礁域における磯魚群集と環境構造の関連性

西田　高志^＊・乾　隆帝・鬼倉　徳雄・及川　信

九州大学大学院農学研究院アクアフィールド科学研究室　〒811-3304　福岡県福津市津屋崎２５０６

Takashi NISHIDA^*, Ryutei INUI, Norio ONIKURA and Shin OIKAWA: Relationships between fish communities and reef structures in northern Kyushu, Japan. Ecol. Civil. Eng. 11(1), 51-62, 2008.

Laboratory of the Aquatic Field Science, Faculty of Agriculture, Kyushu University, Fukuoka 811-3304, Japan

Abstract: Although most of the natural coasts in the temperate regions of Japan are composed of rocky reefs along the shore, there have been only a few reports on the relationships between fish communities and rocky reef structures. In this study, researches on relationships between several reef structures and fish communities were conducted based on long-term observations in the shallow sea areas in northern Kyushu, Japan. These survey areas were divided into 4 environmental clusters by using multivariate statistical techniques based on reef structural data. Further, each environmental cluster that provided the intended meaning was retained. In analyzing fish community data, these survey areas were also classified into four clusters (fish community cluster), and we were able to associate each fish community cluster with its corresponding environmental cluster. In addition, several structural factors were positively or negatively correlated with several fish community data. The diversity index of reef structure correlated positively with the diversity index of fishes and the number of fish species; the proportion of rocky bottom areas and the frequency of sea algal correlated positively with the number of individuals. A negative correlation was observed between average depth and the number of immature individuals. These results suggest that diversity of fish communities require reef structures such as a diversity bottom and abundant algal cover. In addition, immature fish require shallow areas for habitation.

Key words: diversity, fish community, habitat, reef structure, rocky reef

摘要

　日本の純自然海岸の大部分を占める温帯岩礁域における環境構造と動物群集の関連性についての知見は不足している．本研究では北部九州岩礁域における魚類群集をモデルにして，磯の環境構造と魚類群集の関連性について明らかにした．その結果，調査地は４つの環境構造クラスターに区分されること，それぞれのクラスターに標徴種が見られること，魚類群集も４クラスターに区分され，環境構造クラスターと対応関係が見られること，幾つかの環境構造が魚類群集に影響を与えていることが解明された．そして，それらの結果から多様な群集の維持には環境が多様であること，褐藻類が繁茂すること，未成魚の生育場となり得る浅場を含むことが重要であることなどが明らかとなった．

2007年6月18日受付，2007年11月17日受理
* e-mail: anahaze@agr.kyusyu-u.ac.jp