The respiratory rate of three related goby species, Pomatoschistus minutus, P. lozanoi and P. microps, was measured in relation to water temperature. Different methods were tried to measure standard respiration of the resting fish and active respiration of the swimming fish, in order to estimate the respiratory scope for activity in relation to temperature. The methods appeared to be unsuitable for measurements of active respiration, partly because the gobies clinged to the bottom and refused to swim in a proper way. Standard respiration was measured in the three species at water temperatures of 5°,6.5°,10°,15°, 20° and 25°C. There was no endogenous daily rhythm nor a marked group effect in the standard respiratory rate. The standard respiration at 14.5°C in relation to a decreasing oxygen content showed that the respiration remained independent of oxygen content of the water down to a level of 10-20% saturation. Finally the relation between body length and weight was measured for the three goby species. |
