The mammoth earthquake and tsunami that resulted in the death of tens of thousands and wiped out coastal cities in northeast Japan left the region to deal with 22 million tons of rubble, perhaps the biggest recycling challenge ever. It examined a way of manufacturing the concrete block as substrata for seaweed, which used concrete rubble. The postpacked and prepacked concrete using recycled coarse aggregate, concrete rubbles were experimented. As the result, the postpacked method was easy for the blocks as seaweed breeding reef to be composed. At the earthquake-stricken district, concrete blocks as seaweed breeding reef were manufactured using the concrete rubble in March, 2012. Seaweed on the block which were mounted in Otsuchi area in Iwate pref. were observed in April, 2013. Seaweed on the block was observed to 13 months after mounting. Cover of the seaweed on the block was 100 %. On the natural rock, it was 80 %.
This study aimed to reveal the effectiveness of Fe-eluting fertilizer in enhancing oyster growth. First, we conducted growth experiments of both the phytoplanktonic diatom Skeletonema costatum, and the attached benthic diatom Nitzchia pellucida, which are supposed to be consumed by oysters. Laboratory growth of the two species when fertilized was as good as when in the standard culture media. We then conducted field experiments focusing on growth enhancement of cultured oysters by applying fertilizer. Our results appeared to be reasonable in terms of oyster growth, but we could not conclude that the results were robust because of the small sampling size, which was inadequate for statistical evaluation.
In order to observe three species of large jellyfishes Nemopilema nomurai, Rhopilema esculentum and Aurelia aurita s.l. which live in the sea around the Japan, the acoustic camera DIDSON was applied. Effective observation methods using acoustic camera for each species were discussed. Acoustic frequency of 1.1 MHz, 20 m-visibility and vertically downward observation was effective setting for N. nomurai that was distributed in the deep offshore water. Acoustic frequency of 1.8 MHz, 10 m-visibility and vertically downward observation from the sea surface was effective setting for R. esculentum that was distributed in the shallow coastal water. Acoustic frequency of 1.8 MHz, 5 m-visibility and horizontal observation was effective setting for Aurelia that was distributed in the coastal water. Experimental surveys using above settings were carried out by research ships and fishing boat. Individuals of each jellyfish could be visualized clearly on the pictures of the acoustic camera, and data of population density, bell size and swimming direction of each jellyfish were acquired.
There is currently little information about the physical properties of coarse sand beach habitats for organisms. To elucidate the physical properties of the shoreline areas of sandy beaches, the saturation level using glass beads of an equivalent particle size was measured using suction. The sediment hardness was also measured using three different instruments to examine the basic physical properties in shoreline areas of sandy beaches, especially coarse sand. Suction values, increase as the particle size is decreases. Three different hardness indexes indicated that glass beads with a grain size of more than 1 mm have the same nature as a gravel. Where the grain size of the glass beads was less than 0.5 mm, penetration resistance was connected with a decline of the saturated water level and correspondingly increased. Where the grain size of the glass beads was less than 0.7 mm, deep vane shear was connected with a decline of the saturated water level and correspondingly increased. Where the grain size of the glass beads was less than 1mm, vane shear was connected with a decline of the saturated water level and correspondingly increased. These results indicate that there is a difference in processes corresponding with the shift of the physical nature from gravel to sand based on the grain size of sand equivalence.
Since the establishment of “Coastal Fishing Ground Improvement and Development Law”of 1974, fishing port construction industries had been requested superior construction management engineers could conduct the proper construction management, with corresponding to the characteristics of fisheries public works. The construction management engineer makes plans for public works as a chief engineer and manages necessary technical issues for process and safety at a construction site. Training courses for fisheries construction management engineer have been started since 1986, have trained so far fisheries construction management engineers more than 10,000. Fisheries construction management engineers have come to be placed as “construction environment supervisors”since 2009, in case of fisheries public works such as fishing port, fishing ground and like that should be environmentally friendly.
This report shows the standard design of artificial reefs and the effect research guidelines of artificial reefs in Korea. Fishing grounds construction referred to as the marine culture in Korea is being carried out diligently in the same way as Japan. It is also the same as that of Japan, which has been carried out at the public work. For this reason, effective investigation of an artificial reef guidelines have been made for the construction method of reef fisheries. Until now, it has not been published so much in Japan, because the opportunity to present the public, introduce one part of these.