By results of fish experiments with which fish reefs areas and control areas were compared, the reef affinity index was defined and calculated. And, the results of the fish experiments classified by distance were applied to an approximate expression and the distance distribution from fish reefs of the fish species was quantified. It was suggested that fish reef affinity was formed by acquisition competition to feed during of the fish species and food chain. From results of the reef affinity index and the distributions of fishes, it was shown to be able to presume the attracting amount from the distribution of fish. And relational expression H=N_0-N_0・e^<-AC_V×bV>+N_0・AC_S・e^<-AC_V×bV> of the stock abundance N_0, the attracting amount H and the fish reefs volume bV was proposed.

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According to the development for the observations of topographical upwelling, technical developments for artificial upwelling are being carried out at present So far, topographical upwelling currents are known to be affected by the features of seabed, or generated at the downstream of capes and islands. This study shows some theories about upwelling to be generated at the downstream of camelback shape of topography and cape, and then calculated the amount of the upwelling. It also represents experiment results that artificially generated upwelling using double walls. This study would be helpful to some other studies taking advantage of topographical upwelling.

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Artificial mound reefs have been recognized to be effective for ocean nourishment and fishing ground development This paper introduces their basic functions, benefits and project processes from planning to verification, and describes various investigation and experiments in practical works. As the results, several new technologies such as numerical simulation, field observation, construction methods and construction managements are integrated. The advanced system is successful in high-resolution placement of artificial mound reefs.

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Rolling produces the largest oscillations of any ship motion, and in small fishing boats (less than 20 tons), large angle oscillations are also produced by sporadic waves such as ship-generated waves. Various types of hull appendages are attached to reduce rolling in small fishing boats while they are working. These hull appendages are attached based on the empirical knowledge of fishing boat users and engineers at small shipyards. Therefore, the mechanism by which rolling is reduced has not been elucidated, and there are some cases where rolling cannot be reduced even if hull appendages are attached. Therefore, it is necessary to elucidate the mechanism whereby hull appendages reduce hull rolling, and quantitatively indicate the reduction in roll. Also, the environment confronting fishing boat operations is extremely difficult at present due to the high oil prices, reduced fish catches and low fish prices seen in recent years. Rising fuel prices have had a particularly large effect on fishermen's works. Therefore, efforts are being made to promote energy conservation on fishing boats. These include lowering navigation speeds, and traveling with a lighter hull by not carrying unnecessary baggage on boats. However, few small fishing boats are equipped with a fuel flow meter, and at present it is impossible to accurately ascertain the amount of fuel used in operations. In order to improve the energy efficiency of fishing boats, it is necessary to clarify the fuel consumption characteristics in the various processes involved in operations. This paper discusses research done to reduce hull rolling and research on fishing boat energy conservation, and suggests how to continue this research in the future.

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To develop new trawl gear corresponded to sustainable utilization of fisheries resources, it is necessary to investigate the gear efficiency at multiple view point This paper deals quantitatively with analysis on the gear efficiency in various directions. Authors conducted a series of experiments for two types of trawling gear; beam trawl and wing-kite trawl. We investigated the gear efficiency at view points of not only the physical characteristic and catching efficiency but also the physical loads on the crew at the fishing operation. The physical characteristics of two types of trawl were measured directly using the underwater instruments. The fishing efficiency of two types trawl was analyzed on the catches. The physical loads on the crew were estimated using the Ovako Working-Posture Analyzing System (OWAS). The physical characteristics of beam trawl and wing-kite trawl; the height of net, the distance of wing tips, the resistance of gear and the sinking speed of net are almost same. The catch composition and the length composition are same in two types of trawl, although the catch weight of beam trawl was a half of wing-kite trawl. The operation of beam trawl was more complex than that of wing-kite trawl. The physical loads on the crew in wing-kite trawl were 73% at shooting net and 50% of hauling net compared to that in beam trawl. Wing-kite trawl has same physical characteristics, higher catching efficiency and less physical loads on the crew to beam trawl.

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This paper addresses the dynamics model of an underwater vehicle with a water-jet propulsion system. Our aim is to develop the vehicle for the use of oceanographic survey, fisheries and ocean exploration. Hydrodynamic forces acting on the vehicle with 4 fins are determined for -90.0〜90.0 degrees of attack angle and -2.0〜2.0 of non-dimensional rate of turn including conventional towing tank test such as Oblique towing test and Circular motion test.In addition, in order to characterize the effects of vehicle motion on water-jet forces, experiments to measure the side force and yaw moment produced by water-jet units have been made. A water-jet model is also incorporated into the simulation. The model is used to simulate the vehicle. The authors use the simulation as a predictive design tool to evaluate and compare the performance of the vehicle before it has been fully developed.

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It is clear that the deep sea water is useful for creature production because many of the world excellent fishing grounds are located in the deep sea water upwelling areas. The pumping deep sea water pump is a pump that pumps up the deep water to the surface of the sea by used the wave motion of the sea surface. The author calls it "wave motion pump pumping deep water" afterward. This paper proposes the structure, the pumping principle, the theory and the pumping discharge of the wave motion pump pumping deep water. The pumping discharge of the deep seawater is a function of the dimension of the parts of the pump (tube diameter d, length of the tube l and bellows diameter D) and the waves scales (wave high H and period T).

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Designing of facilities such as set-nets, net cages, and artificial reefs requires calculation of the wave force. However, wave force calculations have previously been made using a computer because the mathematical treatment of waves is complex and even in the easiest wave theory, a hyperbolic function was applied. Furthermore it needed an integral calculation incorporating the water depth. On the other hand, currently available scientific electronic calculators are commonly equipped with a hyperbolic function and memory function. Consequently, we devised a simplified method of wave force calculation using a scientific electronic calculator and compared it with the conventional method using a computer. We regarded such fishery facilities as submerged spheres and cylinders for the sake of simplicity and calculated the wave force acting on them by both methods. It became clear that we can regard that there is little difference between wave force estimated by the simplified method and the one by the conventional method. That means the simplified method is effective. Therefore, although wave calculation in the past required a computer, the calculation by the simplified method requires only a scientific electronic calculator, which allows the wave calculation to be easily done by hand.

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We made some modifications to the original chevron-type Larinier pass, such that refuges (dented spaces) were installed at approximately regular intervals on the side walls. Then we carried out hydraulic experiments and fish behavior observations on two kinds of fish released into the modified models. The major results are as follows: 1) the unit width flow rates of such "shallow" streaming type fishways are approximately 2-3 times of those of "deep" streaming types such as Fatou (or Steep) Pass and the standard Denil. 2) there are some routes likely to be chosen by ascending fish at a high frequency even in the highly complicated flow with various hydraulic conditions similar to the natural riffle in the "lay-by attached boat-passage fishway".

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