有明海・八代海沿岸の河口干潟におけるムツゴロウの分布と生息密度

抄録

The distribution and population density of the endangered mudskipper, Boleophthalmus pectinirostris, in estuaries in Ariake and Yatsushiro Bay, were surveyed in September, 2003. The species was observed at 108 of 197 surveyed locations in Ariake Bay and 14 of 39 locations in Yatsushiro Bay. Comparison with the previous investigation in 1991 indicated a small distribution extension, although, the population in the inner part of Isahaya Bay (Ariake Bay) was likely to be extinct, undoubtedly due to the Isahaya Bay reclamation project, which has resulted in more than 80% loss of estuarine habitats in that part of Nagasaki Prefecture. In most areas except for the inner part of Isahaya Bay, both distribution and population density of B. pectinirostris have shown a tendency to increase since the middle 1980s, when the species was in a very serious condition. But, past dynamics of both distribution and population density indicate the possibility that they fluctuate several-year time scale, showing that a species and habitat protection policy for B. pectinirostris should be established in all areas, as has been done for the Saga Prefecture portion of Ariake Bay.