Japanese conservationists are trying to control the population of North American invasive freshwater crayfish or red swamp crayfish, Procambarus clarkii, which negatively impacts the native water ecosystem in the Japanese Archipelago, by removing them. To compare the efficiency of catching, four types of traps with different shapes （A, Semi-sphere type; B, Cube type or crab trap; C, Net type or shrimp trap; D, Plastic-bottle） werearranged in ponds adjacent Lake Izunuma-Uchinuma, Miyagi Prefecture, Japan. The semisphere type trap （A） showed the highest catching ability. Additionally, to develop more suitable methods for the management of the traps, freshness of bait used for the trap and the frequency of the removal of an entered crayfish in the trap were compared. The freshness of bait in the collecting gear and occurrence of crayfish individuals in cage traps affect to newly entrance of P. clarkii. It is suggested that an effective method for the collection of alien P. clarkii is the use of the semi-sphere type trap and daily maintenance of the cage trap, which involves changing the old bait and removing the trapped individuals.

The critical habitat for the larvae of endangered arctic lamprey dwelling in southern limited of habituation was studied by field environmental survey and laboratory rearing experiment. The study site was selected in the middle reach of the Machino River in Noto Peninsula, Ishikawa Prefecture. The eight sections （inside side cavity and outside side cavity） were established laterally along river shore. The bored larvae in fine substrate were captured using electric fisher, and environmental variables were measured in each section. Density of larvae in the side cavity section was consistently larger than control sites. Very fine sand （under 0.125 mm） and organic matter in the side cavity were significantly higher than the control sites. Velocity in the side cavity were slower than the control sites. However, there was a wide variation of larvae density among the side cavities. Toreveal the critical environment factor for larvae in the side cavity, lamprey larvae were reared in the tank where three different particles （under 0.25 mm, 0.25 mm~1 mm and gravel） and organic matter containing ratio （8%, 2% and 0%） were prepared. Larvae mostly preferred the finer particle （under 0.25 mm） and no organic matter where ORP value was the lowest. It is concluded that the aerobic condition with fine particle in the substrate is mostly significant for creating a favorable lamprey larvae habitat.

We focused on artificial spawning beds for a conservation method of endangered bitterling fish inhabiting agricultural channels. To clarify any preference for host mussel species by bitterling fish, we conducted a field experiment to set artificial spawning beds in an agricultural channel in southern Okayama, western Japan, between March and August 2014. We set nine artificial spawning beds （50 cm×36 cm×8 cm） each with a singlespecies of three mussel species （Unio douglasiae nipponensis, Pronodularia japanensis and Lanceolaria grayana cuspidata） made of rectangular plastic trays at the experimental site. After three weeks, we retrieved the mussels from the spawning beds and then individually reared them in aquaria in the laboratory to observe the number and the species of bitterling juveniles that emerged from each host mussel. The total number of juveniles that emerged from the host mussels was 679（420 from U. douglasiae nipponensis and 259 from P. japanensis; no individuals from L. grayana cuspidata）. We identified four bitterling species including three endangered native Tanakia limbata, Tanakia lanceolata and Acheilognathus rhombeus, as well as the invasive Rhodeus ocellatus ocellatus, but the number of A. rhombeus was only 9 because this fish is an autumn-spawning species and thus spawned before the experiment （i.e., in 2013）. Rhodeus ocellatus ocellatus spawned U. douglasiae nipponensis and P. japanensis, but T. limbata and T. lanceolata utilized only P. japanensis as host mussels, indicating that host mussel preference differed among the three bitterling species. In this study, an endangered species Rhodeus atremius suigensis, inhabiting the experimental channel, designated as a Nationally Endangered Species of Wild Fauna and Flora by the Ministry of Environment of Japan did not utilize the spawning beds. We need to clarify the preference for mussel species and appropriate artificial spawning beds for R. atremius suigensis.

River environments consist of many things that are difficult to discern visually because they are hidden underwater. And as ecological processes are complicated andfluctuate and habitats go from a micro to wide-scale ones, it is difficult to observe many of the ecological processes and phenomena on-site. In interpreting the above processes, it is necessary to have an exhibition theory based on an ecological point of view of a river. In this study, we considered a theory on how to understand and visualize ecological processes in a river, with references to ecological exhibitions in aquariums and related facilities. First, we found the viewpoints of the exhibitions by looking at the relation between habitat classification that references past related ecological research and the restricted mattersor trends regarding human perspectives. In addition, in order to create a good ecological exhibition, a typical aqua-scape including the target habitats was selected, and cross-sectional views were extracted from the viewpoint of passing through the relevant space. This showed it is important to reproduce aquatic organisms and vegetation in ecotones, placement of a micro-topography and light that is suitable for the target natural environment. With regards to human perspectives, in order to observe the relationship between livingorganisms and the surrounding environment, we clarified the importance of securing good vantage points and multiple angles of elevation for observing phenomena. Lastly, we considered information media such as illustrations and movies which complement and expand the exhibits and discussed events that are difficult to see with the naked eye. In this way, we showed the effectiveness and applicability of the information media in terms of being able to visualize information by expanding or reducing time.

A learning program of outdoor environmental education for university students was conducted to make stream ecosystem diversity understandable from 22 to 26 August 2016 in the Yusuhara-gawa River of the Shimant-gawa River branch, Yusuhara, Kochi Prefecture, Japan. In order to improve the educational effect of nature experience learning, we conducted an indirect experience of the research site using Google Earth in advance learning and confirmed the educational effect. The students repeatedly learned while repeatedly moving through a section of the river including various environments, for example, riffles and pools with sand, gravel and bedrock. From the after questionnaire survey, it was confirmed that the students understood that the river contained various environments. Students in teacher education course accounting for half of the participants were strongly requested to learn knowledge about safety, looking at their own near future. From the descriptions of the students written in the questionnaire it was confirmed that this program was able to respond adequately to their needs.

I reviewed the history and perspectives of ＂Ecology and Civil Engineering Society＂, checking its official journal ＂Ecology and Civil Engineering＂. During the first five years, many special issues （features） were launched, e.g. Restoration of riverine nature, Effects of dams, Japanese coast ecosystems, Evaluation of fish ways, River health, Evaluation of the monitoring of Nagara River Barrage etc. The major fields of submitted articles were rivers and streams, and dams or barrages followed. As a whole, the collaborations between ecologists and civil engineers and that of public officers, private company engineers, andacademic researcher have been well established in these twenty years.

In recent years, I feel strongly that social circumstances surrounding ecology and civil engineering society are changing drastically. One of them is the appearance of theconcept of green infrastructure. Green infrastructure is a concept of natural resources as an infrastructure which is a lower structure supporting society and furthermore the concept of utilizing the natural environment for sustainable maintenance or development of society and economy. For the society based on ecology and civil engineering, it can be said that it is a concept or approach with extremely high affinity. The initial goal of the establishment of the society was ＂coexistence of people and living things＂＂ preservation of biodiversity＂＂ sustainment of healthy ecosystems＂. The green infrastructure aims to ＂utilize the functions of ecosystems for management of the national land.＂ Boldly speaking about green infrastructure is to shift from ＂conservation of ecosystem＂ to ＂conservation＋utilization of ecosystem＂ and from ＂civil engineering＂ to ＂land management＂. When considering the development of ecology and civil engineering society, I feel that it is important to clearly position this new concept as a goal of the academic society.