Abstract
Effects of grouping on respiration of the medaka Oryzias latipes were investigated using through-flow respirometers and sealed flasks.The oxygen tension of water was measured with polarographic oxygen electrodes.The potential changes accompanying re-spiratory movements were recorded with electrodes of platinum, active and indifferent, in order to determine the ventilatory frequency.The oxygen consumption and the ventilatory frequency of isolated fish in the respirometer tube did not change when the fish were placed in contact through vision alone with their own mirror images, or with others of the same species.The oxygen consumption of isolated fish in the sealed flask was also not affected by visual contact with others of its kind.The oxygen consumption of isolated fish in the sealed flasks slightly decreased when they were placed together in a group of formerly-isolated fish in another flask filled with water which was exactly the same as the total volume of water used for each isolated fish.However, the decrease was too slight to suggest that the metabolic rate of isolated fish is influenced by the changes in visual con-ditions and by direct contact with others of its kind.
