Chiba University - Minamiizu

Restoration Project

Chiba University - Minamiizu

Restoration Objective:

The aim of the present study was to determine whether large sporophytes originating from Nabeta Bay would turn into small sporophytes with short stipes when transplanted to Nakagi Bay.

Cause Of Decline:

Ecklonia cava is a large perennial kelp and forms a dense forest along the coast from central to southern Japan. The kelp forest plays an important role as nursery and breeding space for commercial fish, shellfish and other animals, and has high productivity. Recently, it has been reported that marine plant communities, including kelp forests, have disappeared or diminished along the Japanese coast. As an extreme example, 180 ha of E. cava forest disappeared in Tosa Bay, resulting in a collapse of the abalone fishery.

Key Reasons For Decline:


Scientific Paper

Growth and survival rates of large-type sporophytes of Ecklonia cava transplanted to a growth environment with small-type sporophytes

Y. Serisawa, M. Aoki, T. Hirata, A. Bellgrove, Tsuchiya Kurashima, Y. Yokohama
Journal of applied phycology, Vol. 15.


Site Observations:

Observation Date

15th Dec 1996 – 15th Dec 1998

Action Summary:

Ten small juvenile E. cava sporophytes with stipes < 5 cm were collected at 5–10 m depth from Nakagi Bay. These were blotted dry and attached to artificial slates (10 x 10cm and 0.4cm thick, made of asbestos and cement) using a jelly-type instant adhesive. Prior to transplantation artificial reefs were settled on the sandy bottom at 9m depth in Nakagi Bay. Four concrete blocks (50 × 60 × 54 cm) were fixed in a straight line with stainless steel tubes (5 cm diameter). Five slates with sporophytes were attached to each artificial reef (2 blocks with Nakagi sporophytes and 2 with Nabeta sporophytes) using water-resistant epoxy resin adhesive.

Lessons Learned:

Not focused on restoration.

Project Outcomes:

The survival rate of the Nakagi sporophytes was about 100% in 1996, 60–80% in 1997, then 50% until July 1998, subsequently decreasing to 0% in December 1998.

Key Reasons For Decline:


Indicator Data:


Ending Value:

Starting Value:

Percent Survival