JFE R&D Corporation - Jogashima

Restoration Project

JFE R&D Corporation - Jogashima

Restoration Objective:

This study aimed to observe the growth of Ecklonia cava on Marine Blocks and ordinary concrete blocks, and to survey the formation of seaweed beds on Marine Blocks. Marine forests play an important role as nursery and breeding spaces for commercial fish, shellfish, and other animals such as abalone and sea urchin. Therefore, it is important to study the growth of Ecklonia cava on a Marine Block in order to evaluate the suitability of this new material as artificial reef.

Site Selection Criteria:

A site was selected where an Ecklonia cava forest was present nearby.

Cause Of Decline:

Rocky intertidal reefs are often dominated by canopy-forming fucoid algae, which are often important ecosystem engineers. However, these same species are highly susceptible to anthropogenic disturbances in the nearshore coastal environment, such as human trampling, coastal sedimentation and sewage effluent discharge. In temperate Australasia, Hormosira banksii dominates much of the intertidal coastline and has many characteristics that suggest it is an important ecosystem engineer and can be negatively affected by sewage effluent discharge.

Key Reasons For Decline:


Scientific Paper

A field test of porous carbonated blocks used as artificial reef in seaweed beds of Ecklonia cava. Springer

K. Oyamada, M. Tsukidate, Takahashi Watanabe, Isoo T., T. Terawaki
Nineteenth International Seaweed Symposium.


Site Observations:

Observation Date

15th Nov 2001 – 15th Mar 2006

Action Summary:

In 2001, five existing concrete blocks were placed with 5 cubic marine blocks (1 x 1 x 1m). The blocks were placed on relatively flat areas of sea floor scattered across this terrain. Scuba-diving observations and measurements were used to count the number of Ecklonia cava and Sargassum plants and other attached organisms on each block until April 2006. Marine blocks contained CaCO3 and iron to enhance kelp growth.

Project Outcomes:

A large number of seaweed and animal species were observed on the Marine Blocks, and it was found that growth rate, plant length and wet weight of E. cava were greater on Marine Blocks than on concrete blocks.

Key Reasons For Decline:


Area of Restoration (Ha)


Indicator Data:


Ending Value:

Starting Value:

Adult Kelp Density

/ m2
/ m2