The permeability to oxygen of the swimbladder of the mesopelagic fish Ceratoscopelus maderensis

The permeability to oxygen of the swimbladder of physoclistous fish is important because of the usually high oxygen content of the bladder. The oxygen permeability and guanine content of the swimbladder wall of the mesopelagic myctophid Ceratoscopelus maderensis (Lowe) were measured. The oxygen permeability was 0.0672 cm³ m/atm min cm² and the guanine content was 73 g/cm². Attention is drawn to the high rates of gas loss which would occur from a swimbladder with these characteristics and the problems of maintaining the gas content, especially at depth.