PROBLEM TO BE SOLVED: To provide a seaweed bed protection method that protects seaweed from feeding damage by fishes until the seaweed is spread, increased and grown in a concrete block reef.SOLUTION: A seaweed bed protection method is provided for protecting a seaweed bed from feeding damage by fishes. In the method, the periphery of a concrete block reef 30 to be installed underwater is enclosed by a net material 10 from a water surface to a water bottom； a lower part of the net material 10 is conformed to the water bottom using a weight； an upper part of the net material 10 is held by an upper part cord-like body 11, and also the upper part cord-like body 11 is held in the vicinity of the surface of the water with a holding floating body 20 and is pulled with an underwater cord-like body 14 from a landmark floating body 21 provided in an end of the upper part cord-like body 11 toward the water bottom； and the end of the underwater cord-like body 14 is positioned and held with a water bottom fixing member 40.SELECTED DRAWING: Figure 1【課題】コンクリートブロック礁に藻類が繁殖及び増殖して生長するまで魚類による食害から保護する藻場保護方法を提供すること。【解決手段】藻場を魚類による食害から保護する藻場保護方法であって、水中に設置するコンクリートブロック礁３０の周囲を水面から水底まで網材１０によって囲い、網材１０の下部は重りで水底に沿うようにし、網材１０の上部を上部索状体１１で保持するとともに、上部索状体１１を保持浮体２０で水面付近に保持し、上部索状体１１の端部に設けた目印浮体２１から水底に向けて水中索状体１４で引っ張り、水中索状体１４の端部を水底固定部材４０で位置保持するようにした。【選択図】図１
