PROBLEM TO BE SOLVED: To provide a seaweed bed which does not damage a seaweed body such as kelp to be cultivated, hard to become a habitat of sea urchins and the like, and hard to be buried even when put on a sandy place.SOLUTION: The seaweed bed 1 has a doughnut-like shape concrete block seaweed bed body 2 at the center of which a through-hole 4 is made, and is provided with a plurality of seawater-passing part 3 through which seawater is passed to the side of the through-hole 4 from the side of the outer peripheral surface of the seaweed bed body at the side of the bottom surface of the seaweed bed body 2. The seaweed bed is reduced, as much as possible, in damaging the seaweed body to be cultivated because the seaweed bed body 2 has a doughnut-like shape, and sea urchins and the like are hard to grovel up on the surface of the seaweed bed so as to prevent the seaweed body from feeding damage by the sea urchins and the like because the surface is formed into a curved one and has no unevenness. The seawater-passing part 3 is formed on the bottom surface of the seaweed bed body 2 and thereby the seawater passes through the seawater-passing part 3 and is discharged from the through-hole 4 at the center of the seaweed bed body 2 even when the seawater hits the outer peripheral surface of the seaweed bed body 2, so that a scour phenomenon is suppressed as much as possible and the seaweed bed body is prevented almost completely from burying even when put on the sandy place.【課題】コンブ等の育成すべき藻体に対し傷を付けることなく、ウニ等の住処にもなり難く、かつ、砂地に設置しても埋没し難い藻礁を提供する。【解決手段】この藻礁１は、中央部に貫通孔４を有するドーナツ形状のコンクリートブロック製礁体２を有し、その礁体２の底面側には、その外周面側から貫通孔４側へ海水を通す海水通し部３が複数設けられている。礁体２がドーナツ形状であるため、育成すべき藻体に対し傷を付けることを極力低減でき、またその表面は曲面をなしており凸凹がないので、ウニ等がその表面を這い上がり難く、ウニ等による藻体の食害を防止できる。また、礁体２の底面には海水通し部２が設けられているので、礁体２の外周面に海水が当っても海水通し部３を通って礁体２中央の貫通孔４から海水が排出されるため、洗掘現象を極力抑えることが可能となり、砂地に設置しても埋没することを極力防止できる。【選択図】図２
