PROBLEM TO BE SOLVED: To provide an algae reef that can prevent the feeding damage particularly by conches.SOLUTION: An algae reef A is provided for being sunk in the sea to make marine algae grow thick. The algae reef has a base 1 and column members 2 being set up from the base 1. An intrusion prevention part B to prevent the entry of conches is formed in the lower end side of the column member 2. The intrusion prevention part B is constituted of an irregular part 11 having multiple irregularities where an interval between adjacent protrusions 11a is substantially equal to or smaller than the height dimension of the conch 10, or a needle-shaped projection part 12 having many needle-shaped protrusions, or a fabric part 13 having many flexible fibers.SELECTED DRAWING: Figure 1【課題】特に巻貝による食害を防ぐことができる藻礁を提供する。【解決手段】海中に沈下させて海藻を繁茂させるための藻礁Ａであって、基台１と、該基台１から起立した柱体２と、を有し、柱体２の下端側に巻貝の侵入を防ぐための侵入防止部Ｂが形成されており、侵入防止部Ｂは、隣接する凸部１１ａどうしの間隔が巻貝１０の高さ寸法と略等しいか小さい複数の凹凸を有する凹凸部１１、又は多数の針状の突起を有する針状突起状部１２、或いは多数の可撓性を有する繊維を有する布状部１３、によって構成されている。【選択図】 図１
