Aquacultural environment lab.

To enhance limited fisheries resources, artificial habitats have been built with various types of structures such as fish aggregating devices, shelters made of concrete blocks for juvenile fishes, and offshore breakwaters for nearshore aquaculture. In this laboratory, we examine what environmental conditions are suitable for the survivorship, growth and reproduction of economically important species and how the organisms respond to physical conditions created in water tanks.
Major facilities
Facilities Specifications
Test device for culture of hanging methods A horizontally and vertically movable arm controlled with a PC can simulate orbital motion of culture nettings in a 2m~2m~2m water tank.
Oscillating flow tank Periodically oscillating water flows can be produced in a 30 cm high, 30 cm wide, 2 m long test section. The maximum of the peak water velocity is 114 cm/sec at the cyclic period of 4 sec.
Recirculating flow tank Steady or oscillating water flows can be produced in a 6 m long, 0.6 m wide, 1 m deep test section. The maximum steady flow velocity is 1.5 m/sec at the depth of 80 cm.
Water wave basin Periodic waves with a cyclic period of 1.4 - 2.4 sec can be produced in a rectangular basin of 4.3 m width ~ 9.4 m on-offshore length ~ 1 m depth. The maximum wave height is 30 cm at the water depth of 70 cm.
Wave channel Periodic waves can be produced in a 18.5 m long, 0.6 m wide, and 1 m deep water channel. The maximum wave height is 30 cm at the water depth of 70 cm and the cyclic period of 1.4 sec.
Shell transportation experiment

The photograph shows an experimental scene to study the shell transportation which is induced by wave effects. The live surf clams are accommodated into an experimental tank under artificial wavy conditions. This experiment aims to estimate the dug out conditions of buried shells and mass transport of them by wave effects.

Tank experiment on grazing activity of sea urchins around Laminaria beds

Large populations of sea urchins frequently overgraze on algae and denude the rock substrata, forming "barren grounds". In such areas, however, algae can survive and grow at shallower depths exposed to wave action because the wave-induced water motion becomes harsher at shallower depth and inhibits urchin grazing. Algal beds are thus formed in shallower zones next to deeper urchin-dominated barren zones. This experiment using a water tank which can produce oscillatory flows examines how greatly various intensities of oscillatory flows restrict grazing activity of sea urchins.

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