Monitoring of intertidal fauna and flora on rocky shore and pier wall in southern Iwate

Representative Organization: Tohoku University

2014/04/01 - 2015/03/31
Twice or Thrice a year in Yoshihama bay

Yoshihama bay, Ofunato bay

Field survey

We examine fauna and flora of intertidal organisms in rocky shore to estimate the impact of the 2011 disater and monitor the recovery process. We also survey an alien barnacle which was found after the disaster in northeast Honsyu Japan and examine its expansion in relation to anthropogenic activities by restorations from the disaster.

1. Fauna and flora of intertidal zone before and after the Great East Japan Earthquake Fauna and flora of intertidal zone have been surveyed at Funasaku rocky shore in Yoshihama Bay. Before the 3.11 Earthquake, 14 macro algae were common at three stations in average in the north-west rocky beach. After the event, 8, 10, and 14 species have been observed annually in subsided area in 2012, 2013, and 2014 respectively. On the other hand, 24 invertebrates were common in the intertidal zone at the south-east rocky shore before the earthquake. After the event, 21, 22, and 20 species have been observed annually in 2012, 2013, and 2014, respectively (Fig.1). Fig.1 Changes of fauna and flora in intertidal zone at Funasaku rocky shore in Yoshihama Bay. No. of species 2001-2005 2012 2013 2014 Flora (*1 14 8 10 14 Fauna (*2 24 21 22 20 *1: average number of macro algal species among three station *2: total number of invertebrate species appeared at four stations. 2. In Otsuchi Bay, Surgassum species and kelps were grew well in northern shore on May, on the other hand these macroalgae were poor in southern shore. The vegetation declined as a whole on December, and density of sea urchin Strongyrocentrotus nudus became remarkable. On early March, the vegetation fell into a decline furthermore except Sargassum yessoense. Ephemeral macroalgae such as Lamonaria japonica and Undaria pinnatifida did not burgeoned in this season. This could be caused by grazing of the sea urchin. In Okirai Bay, mergin of sea glass beds were also grazed by the sea urchin at Namiita shore. 3.Biodiversity of sessile community on the pier at Kamihira in Ofunato Bay become increased due to destruction of breakwaters in the baymouth, which had been limited exchange of seawater inside the bay. As a result, invertebrate larvae outside the bay could flow inside and succeeded to settle in 2013. The biodiversity have not changed much folloing two years. However, reconstruction of the breakwaters have been in progress in the baymouth and the biodiversity have to be kept monitoring afterward. 4. Distribution of a new alien barnacle, Perforatus perforates in northern Honshu and southern Hokkaido. Present distribution of P. perforates appeared in Okirai Bay and Otsuchi Bay in Iwate Prefecture in 2012 has been investigated in northern Japan (Aomori Prefecture and southern Hokkaido) in 2014. The barnacle has been observed at 11 sites among 13 surveying sites in Mutsu Bay. But the barnacle has been identified at only one site which was northern end among 5 stations along Pacific coast of Aomori Prefecture. On the other hand, the barnacle has recognized at only one site in among 4 sites along the Japan Sea side of southern Hokkaido and two sites in Hakodate port. From these results, it seemed that the barnacle has not succeeded to expand its distribution to the Pacific side by natural dispersion.

FY2014 Monitoring of intertidal fauna and flora on rocky shore and pier wall in southern Iwate

CTD Ofunato (Kamihira) 1404-1411
CTD Ofunato (Kamihira & Shizu) 1501-1503