魚礁効果に関する多くの研究は漁業に依存しない調査データによるものであり,商業漁業によって得られた漁業依存デー タを用いた研究は少ない.漁獲量および漁獲量を努力量で除して計算された CPUE(Catch per unit effort)は魚礁効果のほ か,操業海域や漁船能力,資源の年および季節変動の影響を受ける.そのため CPUE をそのまま用いた解析からは資源密 度にあたえる魚礁効果を偏りなく評価できない.本研究ではメダイ,ヒラマサおよびイサキについて,上記の問題を避 けるため CPUE 標準化の手法を応用して効果範囲を定量評価した.メダイ資源密度は,魚礁海域では天然海域の約 7.0 倍 であり,効果範囲は魚礁中心から約 350 m と推定された.ヒラマサの効果範囲は約 100 m,イサキでは魚礁の近接海域に 限定されると推定された. キーワード:人工魚礁,対馬海域,CPUE 標準化,資源密度,効果範囲 Most studies on the effects of artificial reefs (AR) have used fishery-independent research

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... data, and very few have utilized actual commercial fisheries data sets (fishery-dependent data) . Commercial fisheries catches and nominal catch per unit effort (CPUE) , which is calculated by dividing catch by effort, are considerably impacted by many factors, including the AR effect, the fishing area, the ship's capacity, and annual and seasonal resource fluctuations. If nominal CPUE data are used for analysis, the independent effects of an AR on resources density cannot be accurately estimated. To overcome the above difficulties, we applied standardized CPUE methods and estimated the spatial range of AR effects for three species (Hyperoglyphe japonica, Seriola lalandi, and Parapristipoma trilineatum) . For H. japonica, the resource density near ARs was seven times higher than that in natural reef areas, with effects ranging up to <350 m from the AR center. For S. lalandi, typical effects ranged up to <100 m from the AR center; however, the effect of AR on P. trilineatum was limited to the immediate AR area.