43
H.-J. Ceccaldi et al. (eds.), Marine Productivity: Perturbations and Resilience of Socio-ecosystems,
DOI 10.1007/978-3-319-13878-7_5, © Springer International Publishing Switzerland 2015
Abstract
The Sanriku Coast facing the Pacifi c Ocean is an important area for fi shing
and aquaculture. The Sanriku Coast was hit hard by the catastrophic
tsunami event produced by the Great East Japan Earthquake on 11 March
2011. The tsunami destroyed not only infrastructures of coastal fi sheries
and aquacultures but also coastal ecosystems, such as the seagrass and
seaweed beds vital for sustainable fi sheries. This study surveyed the
seagrass and seaweed beds in Otsuchi Bay, Iwate prefecture in June 2011
and found that the seaweed beds around the mouth and middle of the bay
were not impacted by the tsunami, but that the seagrass beds in the bay
head had been destroyed. However, observations verifi ed the growth of
seagrass seedlings germinated from seeds produced in previous years.
This response of the seagrass demonstrates its resilience to huge tsunami
events occurring in an interval of several decades. Huge seawall construction plan against tsunami threatens their recovery. The recovery program
in Sanriku Coast must be established on a holistic approach including
social and ecological aspects between land and the sea because coastal
areas are ecotone and also “sociotone” between them.
T. Komatsu (*) • T. Ohtaki • S. Sakamoto
S. Sawayama • Y. Hamana • S. Sasa
Atmosphere and Ocean Research Institute (AORI) ,
University of Tokyo, President of S.F.J.O. (*) of Japan ,
5-1-5, Kashiwanoha , 277-8564 Kashiwa-shi , Japan
e-mail: komatsu@aori.u-tokyo.ac.jp
M. Shibata • K. Shibata
Toyo Corporation , 1-1-6, Yaesu ,
Chuoku , Tokyo 103-8234 , Japan
Impact of the 2011 Tsunami
on Seagrass and Seaweed Beds
in Otsuchi Bay, Sanriku
Coast, Japan
Teruhisa Komatsu , Takayoshi Ohtaki ,
Shingo Sakamoto , Shuhei Sawayama ,
Yasuaki Hamana , Michiharu Shibata ,
Kohji Shibata , and Shuji Sasa
1
Introduction
The Sanriku Coast is a highly fertile coastal zone
where waters from the Oyashio cold water current
encounter the Kuroshio warm water current
(Fig. 1 ) (Kawai 1972 ). Geomorphologically, the
Sanriku Coast comprises semi-enclosed and ria
bays that protect raft and fi shery facilities from
rough sea conditions. Numerous aquaculture facilities are deployed in the ria bays (Komatsu et al.
2002 ), formerly belonging to the Rikuchu National
H.-J. Ceccaldi et al. (eds.), Marine Productivity: Perturbations and Resilience of Socio-ecosystems,
DOI 10.1007/978-3-319-13878-7_5, © Springer International Publishing Switzerland 2015
Abstract
The Sanriku Coast facing the Pacifi c Ocean is an important area for fi shing
and aquaculture. The Sanriku Coast was hit hard by the catastrophic
tsunami event produced by the Great East Japan Earthquake on 11 March
2011. The tsunami destroyed not only infrastructures of coastal fi sheries
and aquacultures but also coastal ecosystems, such as the seagrass and
seaweed beds vital for sustainable fi sheries. This study surveyed the
seagrass and seaweed beds in Otsuchi Bay, Iwate prefecture in June 2011
and found that the seaweed beds around the mouth and middle of the bay
were not impacted by the tsunami, but that the seagrass beds in the bay
head had been destroyed. However, observations verifi ed the growth of
seagrass seedlings germinated from seeds produced in previous years.
This response of the seagrass demonstrates its resilience to huge tsunami
events occurring in an interval of several decades. Huge seawall construction plan against tsunami threatens their recovery. The recovery program
in Sanriku Coast must be established on a holistic approach including
social and ecological aspects between land and the sea because coastal
areas are ecotone and also “sociotone” between them.
T. Komatsu (*) • T. Ohtaki • S. Sakamoto
S. Sawayama • Y. Hamana • S. Sasa
Atmosphere and Ocean Research Institute (AORI) ,
University of Tokyo, President of S.F.J.O. (*) of Japan ,
5-1-5, Kashiwanoha , 277-8564 Kashiwa-shi , Japan
e-mail: komatsu@aori.u-tokyo.ac.jp
M. Shibata • K. Shibata
Toyo Corporation , 1-1-6, Yaesu ,
Chuoku , Tokyo 103-8234 , Japan
Impact of the 2011 Tsunami
on Seagrass and Seaweed Beds
in Otsuchi Bay, Sanriku
Coast, Japan
Teruhisa Komatsu , Takayoshi Ohtaki ,
Shingo Sakamoto , Shuhei Sawayama ,
Yasuaki Hamana , Michiharu Shibata ,
Kohji Shibata , and Shuji Sasa
1
Introduction
The Sanriku Coast is a highly fertile coastal zone
where waters from the Oyashio cold water current
encounter the Kuroshio warm water current
(Fig. 1 ) (Kawai 1972 ). Geomorphologically, the
Sanriku Coast comprises semi-enclosed and ria
bays that protect raft and fi shery facilities from
rough sea conditions. Numerous aquaculture facilities are deployed in the ria bays (Komatsu et al.
2002 ), formerly belonging to the Rikuchu National