On the respiration of Latimeria chalumnae*

Although so far it has not been possible to make any measurements on the respiration of living specimens of Latimeria, a great deal of relevant anatomical information is now available. Quantitative data about the gills of this fish are discussed in relation to their respiratory function and are compared with the gills of other fish from deep waters. A description of gill structure in Latimeria, including electron microscopy, is given and provides measurements which, together with the gill area measurements, enable the diffusing capacity of the gills to be estimated. The comparison of these results with those of other fish suggests that the resting oxygen consumption of Latimeria is about 10 ml/kg/h, which accords well with its likely inactive mode of life. Estimates of the volume of water pumped over the gills are made and of likely changes in oxygen consumption and gill ventilation when the fish is brought to the surface and thereby subjected to a temperature increase of 10° C. It is calculated that the fish will be subjected to severe hypoxic stress which might well be sufficient to cause early death of the fish.