Temperature Responses of Fish and Shellfish
We have studied responses of fish and shellfish to water temperature by means of various experimental devices.
Temperature ranges that fish prefer have been tested for over 30 species: chum salmon and herring prefer 14 to 15°C, jack mackerel and red sea bream 24 to 25°C, and sea bass and black sea bream 28 to 30°C.
We also have clarified lethal temperatures on young and adult shellfishes living along the coast of our country, including Venus clam, short-necked clam, pearl oyster and abalone.

Equipment for the vertical temperature
gradient experiment

Fish Growth under Fluctuating Temperatures
As thermal power plants vary their power output according to electricity demand in daytime and in night hours, the temperature elevation of effluent water also fluctuates. We have studied effects of the fluctuating temperature upon growth of fish and shellfish.
When cultured under a periodically changing temperature regime, the growth of rock bream, red sea bream, Schlegel's black rockfish, Japanese whiting and grunt proceeds normally as long as the temperatures are within their favorable range.

Experiment of the periodical temperature
fluctuation on fish

Water Temperature and Growth of Seaweed
Seaweed grows attached on submerged objects and is susceptible to temperature and other environmental changes.
We have established optimum temperature ranges for growth of young seaweed by means of experimental cultures. Favorable temperatures for growth of brown algae, Eisenia and Ecklonia species, are between 15 and 20°C, and for many of Sargasso species, around 25°C.

Growth of algae under different temperatures

Water Current and Growth of Seaweed
We have constructed an experimental culture device that enables us to reproduce field conditions of water temperature, water current as well as nutrient concentrations, and tested growth of various algae.
It has been found that temperature response of nori (Porphyra), wakame seaweed (Undaria) and Sargasso species depends on water current and nutrient conditions.

Water current tank and a Sargasso species