Reduction of seaweed beds called ‘isoyake’ has happen in most of coastal prefectures in Japan, most of are due to excessive grazing by sea urchins and herbivorous fish. Several studies and countermeasures have been undertaken to recover from barren ground, but there were problems such as one-off trials and impracticality, therefore, it was necessary to show the concept and procedure of systematic measures. First, Isoyake Recovery Guideline (First Edition, Fisheries Agency, 2007) showed the basic concept and concrete procedure for countermeasures as follows. (i) adaptive management for successful reforestation through continuous learning and feedback control, (ii) flow chart consisted for selecting appropriate recovery techniques, (iii) organized cooperation of volunteers, citizens, enterprises, specialists, and local governments to support fishermen. Next, from the elemental technology development for tangible/intangible measures, reforestation facilities that control of sea urchin grazing with stones and blocks, development of sea urchin suction device and technological development to remove the gathering Kyphosua bigibbus with a gill net were briefly outlined.

The objective of the present study was to identify the behavior of oval squid, Sepioteuthis lessoniana, approaching and staying inside the floated squid trap, as well as monitoring the state of trap using interval cameras. A total of 13 squid traps were used and field experiments were performed off the coast of Sakurajima, Kagoshima Bay and off the coast of Sumiyoshi, Tanega-shima Island, at depths of 16.0–40.0 m. An interval camera placed in a waterproof case was installed on the bottom of each squid trap to record images inside the trap and in the vicinity of the entrance every 5 min. The state of each squid trap was classified into three categories of upward, intermediate, bottom-set, based on the analysis of the corresponding images. Various species including oval squid, cuttlefish, Sepia esculenta, slipper lobster, Scyllarides squammosus, Japanese spiny lobster, Panulirus japonicus, and some fish species were observed. The state of the squid trap was upward or intermediate when oval squids were observed inside and in the vicinity of the entrance. No oval squid was observed when the state of the squid trap was bottom-set. When the squid trap was in the bottom-set state, cuttlefish and Japanese spiny lobster stayed in the squid trap at the same time, and it was observed that the Japanese spiny lobster preyed on the cuttlefish.

When a spectrum is estimated using Fourier transform, information regarding time is lost owing to movement from the time domain to the frequency domain. As is evident from the definition of Fourier transform, information in the entire time domain is theoretically required. Time–frequency analysis has been developed to address these issues. In this study, we first explain the Gábor transform, which is a short-time Fourier transform; subsequently, we perform time–frequency analysis of time-series data on ocean waves in Tokyo Bay, measured using wavelet transform, which was improved by Morlet et al., and present the newly obtained findings. Very few studies have analyzed the time and frequency of wind waves with a significant wave height of approximately 1 [m], which have a considerable impact on small fishing boats. Ueno et al. reported that that rolling occurs in a 19 GT small fishing boat, with both amplitudes exceeding 30°, even when the significant wave height is less than 1 [m]. In this case, capsizing does not occur, but it is highly possible that workers on the deck will fall into the sea, and falling into the sea in cold water can directly lead to death.

Model experiments were conducted in the circulation tank and the wave tank in order to investigate the shapes of concrete structures with an air layer to be installed into the opening of fishing ports water area for confining and cultivating sea cucumbers, taking advantage of the property that the air layer inhibits the behavior of creeping aquatic animals. As a result of the experiment in the oscillating water tank, it was found that the models of the longer the basal plate, the shorter the top edge, the lower the both side edges were the less sand accumulation just below the air layer. While, the result of the experiment in the wave tank showed that the sand accumulated just below the air layer of the model originated from the sand scoured contact with the edge of the model. In addition, a negative correlation was found between the amount of sand accumulated below the air layer and the amount of air leaked from the air layer. If the air layer is lost, the ability to confine and cultivate sea cucumbers in the fishing port waters will be lost. Based on these results, the concrete structure with a width of 3 m, a depth of 1.84 m, and a height of 0.6 m was designed based on the model of the shape with the least amount of sand accumulation just below the air layer, and would be used for the demonstration test.

Wind power generation is one of the most promising technologies for converting to renewable energy for a carbon-free society. The equipment is getting large-scale for power generation efficiency, construction efficiency, and failure rate reduction by slowing down. The site location of the Windfarm is shifting from land to offshore to minimize its impact on the environment. Competing for environmental performance is going to be the driving factor of international competition in a new era. Therefore, the requirements for business approval are also changing. Regulations for Environmental Impact Assessments are directed to the entire business life cycle, including suspension and removal, and are not limited to entrance regulations but are sustainable, including monitoring. Is changing.

Toward the realization of carbon neutrality in 2050, the introduction of renewable energy is an important issue in Japan. As one of the important measures for that, the introduction of offshore wind power is being promoted in cooperation with the public and private sectors. Offshore wind projects are a major investment and need to manage and reduce construction risks, and accident risks during their more than 20-year operation period. Class NK contributes to ensuring the safety of construction work through the Marine Warranty Survey work. The Survey is a condition for insurance coverage for construction work. In addition, Class NK provides wind farm certification service to evaluate the conformity of wind turbines and their supporting structures to national standards, and the suitability for local wind conditions, sea conditions, ground conditions, etc. Through this process, we contribute to stable operation and accident prevention. On the other hand, in order to spread offshore wind power generation, it is also important to reduce its lifecycle cost including operation and maintenance. NK Group will participate in the necessary technical studies and will play a role in the spread of offshore wind power.

Information on the impacts of offshore wind farms on fisheries was collected through a survey of the literature on case studies conducted overseas (Europe and United States), demonstration projects in Japan as well as interviews with experts. Based on these results, the basic concepts and the expected impacts of offshore wind farms on fisheries, the importance of monitoring surveys, survey methods for each impact, points to be considered for conducting surveys in response to concerns of fishermen, and cooperation with environmental impact assessments were summarized. In order to plan and carry out effective fishery impact surveys in Japan, it is necessary to consider specific studies to Japan in relation to the fishery and ecological characteristics of the target species.

Offshore wind power is attracting attention as a renewable energy source that can contribute to a carbon-free society. Toward the realization of a carbon-free society, electric vehicles have already begun to spread. In the near future, we will need the electrification of fishing boats. In addition, offshore wind power and fisheries will have to coexist in harmony. One of the issues that must be addressed to promote the fishing industry through offshore wind power generation is to promote the effective use of electric boats and hydrogen fuel cell boats for fishing. In order to promote the use of hydrogen fuel cell fishing boats, it is necessary to build a prototype boat and conduct verification tests, as well as to study how to install and operate battery charging and hydrogen filling facilities. We will also need to conduct environmental and fisheries impact assessments of the sea area where the offshore wind turbine will be installed in the future. The development of a new type of AUV for marine research will improve the efficiency of underwater surveys, and if environmental DNA analysis can be used to identify fish species living in the surrounding waters, these will be a great benefit to the fisheries impact assessment.