Artificial reefs/Breeding reefs/Underwater survey

　A place where seaweed grows in the shallow sea of the coast is called “seaweed bed”.
　Seaweed beds serve as a place for environmental conservation, spawning grounds for marine products such as fish, and hiding places.We would like to introduce an example of seaweed growth on our artificial reefs and breeding reefs in the creation of seaweed bed project.

　

Seaweed growth case

1.Akita Prefecture　ＦＰ1.5Ｇ-Ｂ
2.Akita Prefecture　πBlock８ｔtype
3.Chiba Prefecture　ＦＰ3.25type
4.Ishikawa Prefecture　ＦＰ3.25type
5.Wakayama Prefecture　ＦＰ1.5Ｇ-Ｂ
6.Hyogo Prefecture　ＦＰ2.00type
7.Yamaguchi Prefecture　πBlock２ｔtype
8.Tokushima Prefecture　πBlock８ｔtype
9.Oita Prefecture　Culbase attached FP3.25type
10.Kumamoto Prefecture　πBlock２ｔtype

1.Off the coast of Happo Town, Akita Prefecture

　In the block, epiphytes such as Sargassum confusum, Sargassum horneri, Undaria pinnatifida, and Chondrus ocellatus Holmes were observed.The blocks with Sargassum confusum and Undaria pinnatifida overgrow to 50-60 cm were also confirmed.

Year of creation 2012-2013	ＦＰ１.５Ｇ-Ｂ
Water depth 5-6m
Survey date May 2015 7-10 years after installation
Sargassum confusum	Sargassum horneri / Chondrus ocellatus Holmes	Undaria pinnatifida

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2.Off the coast of Happo Town, Akita Prefecture

　Multiple species of Sargassum sp. overgrown on the upper surface of the block to form a Sargassum bed, and some of them grew to about 1 m. A lot of Undaria pinnatifida and red algae have grown in the gaps of the Sargassum sp.. Haliotis and Apostichopus armata were also observed on the side of the block.

Year of creation　2006-2009			πBlock８ｔtype
water depth　6-7ｍ
Survey date May 2015 7-10 years after installation
Sargassum sp./ Undaria pinnatifida			Sargassum sp./ Apostichopus armata	Haliotis

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3.Off the coast of Tomiyama Town, Chiba Prefecture

　The block was overgrown with Ecklonia cava with 15 to 30 cm. Ecklonia kurome and Sargassum sp. were also seen. In the gaps between seaweeds, small fishes and a few centimeters of juveniles were observed swimming, and blocks and seaweeds had formed a nursery for juveniles.

Year of creation 1999			ＦＰ3.25type
water depth　23ｍ
Survey date: March 2002 2 years after installation
Ecklonia cava			Ecklonia cava /young juveniles of Sebastes inermis	unknown species of young juveniles

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4.Off the coast of Notojima, Ishikawa Prefecture

　A lot of Crassostrea nippona were growing on the surface of the block, and the Sargassum sp. was overgrown at the top. This seaweed bed functioned as a habitat, and many small fishes were seen, and swimming of piscivorous fishes were also observed aiming at it.

Year of creation 2003			ＦＰ3.25type
water depth 17-18ｍ
Survey date: December 2002 9 years after installation
Sargassum sp./ Crassostrea nippona			Sargassum sp.	Sargassum sp. / Wrasse

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5.Off the coast of Wakayama City, Wakayama Prefecture

　A lot of brown algae (Ecklonia cava and Undaria pinnatifida) have grown on the block, and all of the observed Ecklonia cava were young. In the block installed at a depth of 5 m, total of 263 young Ecklonia cava per square meter, weighing 2,615 g were growing.

Year of creation 2005			ＦＰ1.5G-B
water depth 4-11ｍ
Survey date: Aplil-May 2006 7-11months after installation
Undaria pinnatifida / young Ecklonia cava			young Ecklonia cava	collected seaweed

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6.Off the coast of Minamiawaji City, Hyogo Prefecture

　The block was overgrown with large brown algae (Undaria pinnatifida and Sargassum sp.). Among them, Undaria pinnatifida grew on the entire block and grew to 1 m or more, and Mekabu（Sporophyll of Undaria pinnatifida ）was also observed at the root. In addition, a lot of red algae such as Meristotheca papulosa were found.

Year of creation　2009-2011			ＦＰ２.００type
water depth　5-8ｍ
Survey date: March 2015 7 years after installation
▶Survey case video
Undaria pinnatifida			Undaria pinnatifida/ Sargassum sp.	Undaria pinnatifida(Mekabu)/ Meristotheca papulosa

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7.Off the coast of Suo-oshima Town, Yamaguchi Prefecture

　 The upper part of the block and the surface were covered with brown algae (Sargassum horneri, Padina arborescens, Hydroclathrus clathratus, etc.) and red algae. Sargassum horneri was 1 to 2 m overgrown, and some of them have grown to about 4 m and had reached near the sea surface.

Year of creation 2002			πBlock２ｔtype
water depth　5ｍ
Survey date: February 2007 4 years after installation
Sargassum horneri			Hydroclathrus clathratus	Sargassum horneri / Padina arborescens

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8.Off the coast of Anan Town, Tokushima Prefecture

　A lot of brown algae (Ecklonia cava and Sargassum sp.) was observed on the top and sides of the block. In addition, small fishes are swimming near the grown Ecklonia cava, and this seaweed bed was thought to function as a hiding place for them.

Year of creation 1995			πBlock８ｔtype
water depth　7-8ｍ
Survey date: November 2003 8 years after installation
Ecklonia cava/Sargassum sp.			Ecklonia cava	Sargassum sp./ Ecklonia cava

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9.Off the coast of Beppu City, Oita Prefecture

　In this area, we have conducted 9 surveys over 10 years since 2008.
One year after the block was installed, Sargassum sp. grew on the upper surface of the Culbase panel, and 5years later, more Ecklonia kurome were observed. After that, it was confirmed that useful seaweeds such as Sargassum sp. and Ecklonia kurome continued to grow.
　This study demonstrated that Culbase is effective as a seaweed breeding reef and its effectiveness lasts for more than 10 years.

Year of creation 2006，2007			Culbase attached FP3.25type
water depth　12ｍ
Survey date: March 2008 1 year after installation
▶Survey case video
Sargassum sp.			Sargassum sp.	Sargassum sp.
Survey date: April 2012 5years after installation
Ecklonia kurome			Sargassum sp.	Sargassum sp.
Survey date: March 2015 8 years after installation
Ecklonia kurome			Ecklonia kurome	Ecklonia kurome
Survey date: March 2017 10 years after installation
Ecklonia kurome			Ecklonia kurome/ juveniles of Sebastes inermis	Ecklonia kurome/Sargassum sp.

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10.Off the coast of Itsuwa town, Kumamoto Prefecture

　In this area had been scuba dives and surveys of benthos on the blocks for three years, with a lot of macro brown algae observed in each survey.
In the first survey, a lot of Ecklonia kurome were seen. In the second and third surveys, the number of Undaria pinnatifida and Sargassum sp. increased.
In addition, rock fishes observed in the gaps of seaweed tend to increase in number year by year, and it is thought that the block is used as a hiding place.

Year of creation 2005			πBlock２ｔtype
water depth　4ｍ
Survey date: March 2007 16 months after installation
Ecklonia kurome			Sargassum sp./ Sebastes inermis	Meristotheca papulosa/ Ecklonia kurome
Survey date: March 2008 18 months after installation
Ecklonia kurome/Sargassum sp.			young Ecklonia kurome	Ecklonia kurome/Sargassum sp.
Survey date: March 2009 40months after installation
Sargassum sp.			Meristotheca papulosa	Undaria pinnatifida

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