We estimated the aboveground biomass of emergent plants by multiplying dominance ratio by plant coverage (C) and height (H). We mowed the aboveground parts of vegetation and divided them into four types of monocots then measured the dry weights. Causal relationships were observed between the multiplied dominance ratio and aboveground biomass of the plants, with the coefficient of determination range from 0.60 to 0.91. When measuring the aboveground biomass of plants by using the regres- sion formula that we used it is possible to estimate the existing quantity nondestruc- tively. We estimated the aboveground biomass of emergent plants by multiplying dominance ratio by plant coverage (C) and height (H). We mowed the aboveground parts of vegetation and divided them into four types of monocots then measured the dry weights. Causal relationships were observed between the multiplied dominance ratio and aboveground biomass of the plants, with the coefficient of determination range from

Seasonal changes in species composition and abundance of odonate adults were investigated in Lake Izunuma-Uchinuma and the surrounding areas, northeastern Miyagi Prefecture, Japan, from May through October 2014. Thirty-five species and 6,802 individuals belonging to ten families of odonate adults were observed during the study period. The species richness and abundance of odonates were high from June to September and peaked in July. The dominant species were Deielia phaon and Paracercion hieroglyphicum in June and July and then shifted to Sympetrum infuscatum and S. frequens during August to October. The four dominant species, D. phaon, P. hieroglyphicum, S. infuscatum and Ischnura asiatica accounted for 73.7% of the total observed adults. The endangered species such as P. plagiosum represented two or lower percentage of the observed individuals, suggesting the importance of conservation for these endangered species.

Various environmental preservation activities are being conducted to conserve endangered species in Lake Izunuma-Uchinuma located in northern Japan. In order to facilitate these activities, 1/25,000 topographic maps surveyed by Geospatial Inform- ation Authority of Japan in 1968, 1981 and 2001 had been used as base maps of the lake. However, the shoreline of the lake has been changed due to various factors such as feeding damage by swans and flooding and erosion by wave. To enhance the effect- iveness of conservation activities, a precise map based on the assessment of the present status of the lake has been needed. In this study the precise delineation of the water surface of Lake Izunuma-Uchinuma was established using the latest aerial photographs (taken in November 2007) and from this we calculated the area of the water surfaces of the lake. From this information we found that the sizes of water surfaces of the lake Izunuma and Uchinuma were 357 and 119 ha, respectively. These results indicated that the water surface of Izunuma and Uchinuma expanded by 110 and 113 % from 1981 to 2007. Based on the 1/50,000 vegetation map surveyed by Ministry of the Environment in 1985, 88 % of the area of expanded water surface of the lake was dominated by common reed Phragmites australis and Indian rice Zizania latifolia. These results demonstrated that the expansion of the water surface of the lake caused by the loss of plant comm- unities along the lakeshore.

The unionid mussels Cristaria plicata, Nodularia douglasiae, and Sinanodonta spp. were widely distributed in the many ponds and rivers on the floodplain of the Tone River system in the Kanto region. In recent years, however, the population of C. plicata in particular has markedly declined, and there is concern about its extirpation in many local habitats. Consequently, C. plicata is designated as an endangered species on the red list of each prefecture in the Kanto region. On 11 March 2017, we collected C. plicata in the channel of the Watarase retarding basin. The shell length of collected samples was in the range of 180–300 mm. No individuals smaller than 180 mm were found. The results indicated that recruitment in this population was not successful in recent years. As there is little information on the locations currently inhabited by C. plicata in the Kanto region, the first step in the species’ restoration process is to confirm the records of occurrence from previous reports. In addition, genetic analysis of local populations is important because other species or subspecies of freshwater mussels, possibly including C. plicata ssp. have been repeatedly introduced for fisheries in the Kanto region from Lake Biwa in the Kansai region.

Artificial changes in the environment, such as river bank reinforcement, affect fish fauna. In order to document the fish fauna before a scheduled river channel reinforcement in 2018, fishes in Nose River, flowing into northern part of Lake Biwa, Hikone, Shiga Prefecture, western Japan, were collected using casting nets and/or hand nets from April to November 2017. A total of 18 fish species (17 native and one alien species) were collected from the survey sites. Twelve out of these 17 native species are found on the Red list of the Ministry of the Environment on that of Shiga prefecture. Plecoglossus altivelis altivelis and Rhinogobius sp. OM were most abundant at the most upstream and downstream study area, respectively. These records will provide valuable information of the fish fauna in Nose River just before the improvement of this river in 2018.

Xenocorixa vittipennis is found in high-density in ponds with abundant hydrophytes in Honshuu, Shikoku and Kyushu. It is found frequently in its preferred habitat but this is very localized. It is designated as near extinct by the Ministry of the Environment and there are few reports documenting its life history and no reports of its breeding behavior. In this report apparent breeding behavior, which was observed in Miyagi Ken will be discussed. Additionally, the growth of Xenocorixa vittipennis larva observed from April, 2015 to June, 2018 will also be discussed.

The harvest mouse Micromys minutus was recently found in three new localities in Wakabayashi-Ku, Sendai, Miyagi Prefecture, Japan. One was on the left bank (north side) of the Hirose River, north of Tsubonuma, which was previously considered the northernmost range limit of M. minutus in Japan. With the consolidation of farmland and ongoing revetment construction near these localities, suitable grassland habitat for M. minutus is becoming increasingly fragmented. Immediate action should be taken to conserve these newly discovered M. minutus habitats at its northern range limit.

The migratory history of the Hemibarbus barbus species complex in the tidal area of the Miya River, Mie Prefecture, was studied by examining the strontium (Sr) and calcium (Ca) concentration in their otoliths (lapillus) using wavelength dispersive X-ray spectrometry with an electron microprobe. Otolith Sr:Ca ratios of 1 out of 7 specimens remained consistently low from the core to the edge. This specimen with uniformly low Sr: Cr ratios had not experienced a saline environment. Otolith Sr: Ca ratios of 6 out of 7 specimens had increased. These specimens with higher Sr: Ca ratios had experienced salinity in their environment. Otolith Sr: Ca ratios of all specimens showed low value around the core. This low Sr: Ca ratio around the core shows that they migrated to tidal area after living in a fresh-water environment. A high value of otolith Sr: Ca ratios at the edge shows that some adults inhabit a saline environment in the tidal zone. These various patterns of otolith Sr: Ca ratios show that the use salinity rich environments differs among individuals.

We captured Acheilognathus melanogaster in Lake Izunuma-Uchinuma, Miyagi Prefecture, Japan on July 24, 2018. The last observation of the fish in the lake was in 2006 and, thus, this is the first time in twelve years that it has been observed here. A. melanogaster is an endemic bitterling fish in Japan and distributed in basins on the Pacific Ocean side of eastern Honshu Island. In Miyagi Prefecture, the fish species was designated as endangered category I (CR+EN). Fish fauna in the lake is in recovery due to population control of invasive fishes. We speculated that the population control has resulted in redist- ribution of the fish in the lake.