ワカサギの回遊パターンを明らかにするために，まず飼育実験によって飼育水の塩分と耳石Sr：Ca比の直線回帰式を求めた。次いで日本各地のワカサギ耳石の中心核から縁辺に至るSr：Caプロファイルを基に，各水域における個体の塩分履歴を推定した．網走湖，小川原湖の一部の個体，および鷹架沼，宍道湖の全個体のSr：Ca比は常に低い値を示し，一生を湖内に滞留していたことが示唆された．これに対して，海水域で生活したと判断される高いSr：Ca比を有していたのは，八戸沖，三沢沖，閉伊川，追波湾のワカサギと網走湖および小川原湖の一部の個体であった。しかし、閉伊川と小川原湖以外では，海水域の利用は一時的であり，主に汽水域に生息しているものと考えられた．これらの結果から，ワカサギの回遊パターンは個体群によって様々であるが，汽水域における生息期間の生活史に占める割合が大きいことが示された．

Abundance and distribution of resting cysts of toxic dinoflagellates, Alexandrium spp. (A. tamarense and/or A. catenella), were investigated in the surface sediments of Ise Bay and Mikawa Bay in June 2002, using primuline-staining direct count method. The cysts were abundant at innermost part and west of central part of Ise Bay, and eastern part of Mikawa Bay. The cyst density varied from 22 to 2,254 cysts cm^-3 wet sediment (mean=365 cysts cm^-3) and from 31 to 7,311 cysts cm^-3 wet sediment (mean=1,831 cysts cm^-3) in Ise Bay and Mikawa Bay, respectively, showing an increasing trend of cyst abundance from 1980’s when previous monitorings were conducted. It is also evident that, among bays reported so far in Japan, Ise Bay and Mikawa Bay are the ones having, respectively, the high and the highest cyst abundances. The cyst density in both bays tended to increase drastically where mud content exceeds ca. 70%, although this is not always the case. This may indicate that the selective mechanisms of sediment particles by physical factors, such as hydrographic and sedimentation processes, act on cysts strongly but the magnitude of cyst formation in the water column above the sediment also affects the cyst abundance simultaneously.

To elucidate the spatial and temporal dynamics of sources of particulate organic matter (POM) in the estuarine turbidity maximum, surveys (12 cruises) were conducted along the Chikugo River in the innermost Ariake Sea, Japan, from 24 February to 24 April 2005. To elucidate the influence of semi-lunar periodicity, surveys were conducted around the high slack tide in the daytime and were divided into three categories according to the tidal range; spring (>400 cm), medium (200–400 cm), and neap tides (<200 cm). At spring tides, the vertical mixing was strong and the turbidity maximum (>100 NTU) was formed at lower salinity (<5), synchronized approximately with both the maximum of particulate organic carbon and pheophytin concentrations (>5 mgl^-1 and >10μgl^-1, respectively). In contrast, the turbidity was low and higher chlorophyll a concentrations indicated active production of phytoplankton at neap tides. The POM in the surface water at spring tides had stable carbon isotope ratios (δ¹³C, mean±standard deviation: -25.3±0.9‰) and C/N atomic ratios (C/N, 11.6±2.0) significantly higher than those at neap tides (δ¹³C: -26.0±1.0‰, C/N: 7.9±1.4). The results indicate that the POM maximum accompanied by the estuarine turbidity maximum consists of resuspended detritus of both phytoplankton and terrestrial C₃ plants.