Landing behavior (emerging from water) of abe-haze Mugilogobius abei fishes was observed in a test tank equipped with a slope which divides the water-body into two parts, one lager and one smaller water-body. The upper part of the slope emerges from the water forming dry ground (=land). When a number of Abe-haze fishes were put into the smaller water-body, most of them emerged promptly but some of them gradually moved into the lager water-body over the land. The movement to the lager water-body occurred more quickly when the same experiment was repeated. One individual, who seemed dominant, remained in the smaller water-body. When this individual was removed, another one remained in the smaller water-body. When the trials were repeated, the results were much the same. Such dominant individuals sometimes went back and forth in both water-bodies. It seemed that the ranking within abe-haze group becomes more clear and that the territory of the dominant individual becomes larger when the rearing period of that group becomes longer.

We investigated the degree of hypoxia in lotus Nelumbo nucifera vegetation rich areas and its influence on the benthic invertebrate community in Lake Izunuma. Dissolved oxygen concentrations (DO) in areas with high lotus vegetation density tended to be lower than those in areas with open surface water. Lake bottom water in the lotus vegetated areas became hypoxic in September 2013 and August 2014. A total of 8 taxa were captured in and out of the vegetation; 5 species of Chironomidae (Diptera), Donaciinae sp. (Chrysomelidae), Glossiphoniidae sp., and Oligocheata spp. In August 2014, the total density of benthic invertebrates became lowest (< 107 ind. m-²) in all stations, and only 3 taxa were captured: Chironomus plumosus (Chironomidae), Donaciinae sp. and Oligocheata spp. Even though the benthic invertebrate community was composed of low oxygen tolerant species such as Chironomus plumosus, they could not inhabit the areas with lotus vegetation due to extreme hypoxia during the summer.

Capture methods of largemouth bass fry using seine nets and round haul nets were developed. Characteristics and catches per unit effort (CPUE) of these methods were compared with an existing method using dip nets. Seine and round haul nets enabled the capture of bass fry in deeper areas where dip nets cannot be used. Bass fry over 25 mm in TL, which are difficult to catch using dip nets, were captured by seine and round haul net. CPUEs did not differ between the three methods. Bycatch ratios of other fish species by all methods were approximately 1%. Applying these capture methods using seine nets, round haul nets and dip nets according to the body size of bass fry and the seasonal change of bass fry habitat may enhance the capture pressure of largemouth bass fry.

Wintering dabbling ducks forage rice grains remaining on the post-harvest rice fields. Generally, farmers plow the soil of rice fields after harvest to stimulate decomposition of the rice stubbles. In the plowed rice fields, it is easier for ducks to land on and move around the rice field, and to detect predators, than in the unplowed rice fields. But the amount of rice grains remaining on the plowed rice fields is smaller than that in unplowed fields because rice grains are buried under the soil by plowing. I conducted an experiment to examine the effect of post-harvest plowed and unplowed fields with stubble on the foraging behavior of a domestic Mallard duck by comparing the amount of consumed rice grains, the duration for each foraging bout, cumulative time allocated for foraging, and the number of foraging bouts. Except for the intake rate, values recorded in plowed areas without rice stubble were higher than those of unplowed areas. According to the results of this study and previous reports, the combination of unplowed areas, with large amount of rice grains, and plowed areas, with easiness of movement and high efficiency of detecting predators, were thought to be effective at creating foraging sites for dabbling ducks. Considering the environment and the practice of rice cultivation in and around Kaga City, Ishikawa Prefecture, I devised the post-harvest treatment of rice fields named "Passive flooded rice fields with rainfall" or "Amamizu-tambo" and "Rice fields with a complex of plowed and unplowed areas" or "Shimashima-tambo" for the conservation of wintering ducks.

Distribution of exotic freshwater shrimp Neocaridina spp. and native species Paratya compressa improvisa were investigated in rivers, drains, and ponds in northern Miyagi Prefecture. Neocaridina spp. and P. c. improvisa was distributed in 57.0% and 38.6% of sampling sites in rivers or drains, respectively, and then, the number of captured P. c. improvisa per sampling site was less than half of the number of Neocaridina spp.. In the investigation of the ponds, Neocaridina spp. and P. c. improvisa were distributed 11 and 36 sites, respectively. To evaluate competition between the two species, we analyzed distribution patterns of them using generalized linear mixed model. The models indicated that introduction of Neocaridina spp. is caused negative effects on P. c. improvisa in river and pond environment. These results suggest that expansion of Neocaridina spp. and reduction of P. c. improvisa will be going to continue in Miyagi Prefecture.

The use of cutting equipment in order to inhibit the lotus community in an eutrophic lake was examined. Results of the test indicated that cutting two or three times in a season successfully reduced the number of lotus stems. Of the two methods used, sickle and mechanized cutting equipment, neither method was found to be more successful at eliminating the lotus. Per unit effort, however, cutting lotus by mechanized equipment was 4 times more efficient than using the sickle. Considering this, mechanized equipment was more suited to cutting over a large area. By cutting once in each successive 2 years, the lotus community was eliminated on the third year. As a result of these tests, an effective inhibiting method of a lotus community in a lake was revealed.

A juvenile of the Pheasant-tailed Jacana Hydrophasianus chirurgus was observed in Lake Izunuma, Miyagi Prefecture, on 19-20 October 2014. This is the first report of the occurrence of this species in Lake Izunuma.