The haemodynamics of gas resorption from the physoclist swimbladder: the structure and morphometrics of the oval in Pollachim virens (L).

The structure of the oval in saithe is described with particular reference to its vascularisa-tion. The extent of the capillary plexus was found to be greater than previously estimated, covering about 40% of the internal surface area of the bladder. Morphometric assessment of the capillary network enabled estimation of flow rate using the Poiseuille equation. The low potential flow suggested in this work may be a limiting factor in gas loss from the swimbladder and may place restraints on vertical migration.