Cause Of Decline:

Kelp forests and Sargassum beds are not only commercially important themselves but also play an important role in spawning, in fish breeding, and as feeding grounds for many species of commercial fish, shellfish and other organisms. In Japan, grazing by sea urchins has led to an increase in the size and abundance of urchin barren grounds.

Site Observations:

Observation Date

15th Sep 1981 – 15th Jan 1986

Action Summary:

Twenty 1 ton blocks (tetrapods) were placed on an almost flat bottom at a depth of approximately 14m, 300m off the coast. The blocks were placed to coincide with the maturation period of E. cava in September 1981.

Lessons Learned:

Tetrapods grew Ecklonia cava as effectively as natural substrate.

Project Outcomes:

The standing crop of nearby natural communities was 14.7kg/m2. On the blocks, it was 15.3kg/m2. Ecklonia cava samples were collected at 3.2 and 4.8 m. The average standing crop on the natural rock and blocks was 11.2 kg/m2 and 12.4 kg/m2, respectively. The standing crop of both species on the blocks was similar to that of the surrounding natural seaweed forest. The composition and growth of seaweeds on both substrata were also similar.

Key Reasons For Decline:

Overgrazing

Area of Restoration (Ha)

0

Indicator Data:

Indicator:	Ending Value:	Starting Value:
Wet Weight Kelp	15300.0000 g WW/m²	0.0000 g WW/m²

Observation Date

15th Sep 1981 – 15th Jan 1986

Action Summary:

Lessons Learned:

Tetrapods grew Ecklonia cava as effectively as natural substrate.

Project Outcomes:

Key Reasons For Decline:

Overgrazing

Area of Restoration (Ha)

0

Indicator Data:

Indicator:	Ending Value:	Starting Value:
Wet Weight Kelp	12400.0000 g WW/m²	0.0000 g WW/m²

Nippon Tetrapod Co. - Sagami Bay

Restoration Project

Nippon Tetrapod Co. - Sagami Bay

Restoration Objective:

Site Selection Criteria:

Cause Of Decline:

Overgrazing

Settlement of seaweeds on coastal structures

Organisation:

Nippon Tetrapod Co.

Japan

Site Observations:

15th Sep 1981 – 15th Jan 1986

Action Summary:

Lessons Learned:

Project Outcomes:

Overgrazing

0

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Wet Weight Kelp

3. Is Informed By Native Reference Ecosystems, While Considering Environmental Change

4. Supports Ecosystem Recovery Processes

15th Sep 1981 – 15th Jan 1986

Action Summary:

Lessons Learned:

Project Outcomes:

Overgrazing

0

Indicator Data:

Indicator:

Ending Value:

Starting Value:

Wet Weight Kelp

3. Is Informed By Native Reference Ecosystems, While Considering Environmental Change

4. Supports Ecosystem Recovery Processes