We examined the escape rate and escape time of 4 carabid beetles, namely, Cychrus morawitzi, Carabus granulatus yezoensis, Damaster blaptoides rugipennis, and Leptocarabus arboreus ishikarinus, for 4 types of ditch blocks, namely, U-shaped ditch blocks, modified U-shaped ditch blocks with textured inner surfaces, Hydsel® type I ditch blocks, and Hydsel® type II ditch blocks. D. blaptoides rugipennis alone could escape from the U-shaped ditch blocks within the predetermined amount of time. Among the ditch blocks examined, the U-shaped ditch blocks were the most difficult to escape from, and the Hydsel®(types I and II) were the easiest to escape from. Although the escape rates for the modified U-shaped ditch blocks and the Hydsel® ditch blocks were the same, the beetles took more time to escape from the modified U-shaped ditch blocks than from the Hydsel® ditch blocks (types I and II).
To manage the American mink, Neovison vison, effectively, its densities were estimated in the Fujita and Yata Rivers, tributaries of the Abukuma River, in Koriyama, Fukushima Prefecture. For the calculation for the Fujita River, minks were trapped until all field signs disappeared in two study areas set along the river, a 1.8-km-long middle area and a 1.5-km-long lower area, from mid-October to mid-November in 2009 and 2010. For the Yata River, the minks were captured in a 6.5-km-long area extending from the middle to the lower basin of the river from August 3 to September 24, 2010, and the density was estimated using the removal method. Except for the lower area of the Fujita River in 2009 failed to catch some minks, the estimated density of mink per km was 2.8 in 2009 and 2010 in the middle area and 4.7 in 2010 in the lower area of the Fujita River. Estimated by the removal method in the Yata River, it was estimated to be 4.8. These estimated densities approximated or exceeded the maximum density estimated for areas in Britain, Easter Europe, Patagonia, and North America. The high density is probably related to the abundance of prey animals such as frogs and crawfish supplied to these rivers via the waterways around rice paddy fields. The environment of many other tributaries of the Abukuma River is similar to that of the study rivers, and the density of mink in the other tributaries is expected to be equally high. In order to manage the mink population in this region effectively, the simultaneous measures for the whole Abukuma River basin are necessary.
We studied the impacts of human disturbances by boats on wintering waterbirds at 2 sites, in the North and South of Lake Biwa, a Ramsar wetland in Shiga Prefecture, Japan. Most land-feeding ducks (Anas platyrhynchos, An. poecilorhyncha, An. crecca, and An. formosd) slept offshore during the daytime. Herbivorous ducks (An. penelope, An. strepera, and An, falcata) foraged on the water surface. Diving herbivorous waterbirds (Fulica atra) foraged by diving offshore in the North, and by surface-feeding over a wide area of the water surface in the South. Most diving ducks (Ayihya ferina, Ay. fuligula, Ay. marila, and Bucephala clangula) slept on the water surface near the shoreline during the daytime, and some individuals started diving to forage in the afternoon. At both sites, waterbirds were often disturbed by fishing boats. Some birds flew away from the disturbance, but the species foraging in the daytime tended to come back to the same area and resume foraging promptly, whereas the species sleeping in the daytime tended not to come back.
In contemporary Japan, in order to ensure the sustainability of resources, the traditional practice of hunting is on the decline; this perspective on hunting wild animals is related to conveying a symbolic message to people living in the urban areas. In this report, I comprehensively investigate the concept of "attachment" or "kindness" to animals and try to verify whether the "Matagi" (bear hunters), who still practice traditional hunting in Japan, can be considered cruel. Once, I caught it at a place far away from a hunting area, and they were brought together and discussed. The object reached active hunters, retired hunters, wives, schoolchildren, educators, myself, and many others. Although, hunting appears to be a cruel act, to hunters, hunting comes naturally. However, they are only hunting their feeling are such kinds. We should bear in mind that hunting involves not just the killing of animals but also some special activities closely related to his occupation. I believe that an understanding of wild animals existing among people in the context of Japan's biodiversity would aid the development of the nation.
We used a questionnaire survey to gather information on the damage caused by seals to fishing gear and captured fish during 2004-2007 around Akkeshi Bay in Eastern Hokkaido, Japan. The damage to the fishing gear consisted of damage to the small fixed shore net and the gill net. Nine seal-damaged fish species reported are as follows: ice fish (Salangichthys microdon), Pacific herring (Clupea pallasii), Arctic rainbow smelt (Osmerus eperlanus mordax), righteye flounder (Pleuronectidae), Japanese surfsmelt (Hypomesus japonicas), capelin (Spirinchus lanceolatus), sailfin sandfish (Arctoscopus japonicus), saffron cod (Eleginus gracilis), and Japanese fluvial sculpin (Cottidae). These fish species were damaged by Kuril harbor seals and spotted seals. The percentage of fishery damage reported by local fishermen was 2.75 ± 3.53 % (range 0.39-7.92%) of the total catch of each damaged fish in Akkeshi Bay. Two main peaks were observed: one during early spring from March to April and the other during autumn from September to October.