INITIAL SWIM BLADDER INFLATION IN THE LARVAE OF TILAPIA-MOSSAMBICA (PETERS) AND MORONE-SAXATILIS (WALBAUM)

Tilapia and striped bass larvae inflate their swim bladders on the 7th-9th and 5th-7th days after hatching, respectively. The primordial bladder of Tilapia has no pneumatic duct and larvae do not gulp atmospheric gas for the initial swim bladder inflation. Prominent columnar epithelium is characteristics of the bladder of Tilapia prior to inflation. Hypoxic conditions inhibit inflation and result in degeneration of the columnar epithelium and the irreversible malfunction of the swim bladder. The swim bladder of the striped bass has a glandular epithelium and a pneumatic duct prior to inflation. The mode of the initial inflation and functional role of the pneumatic duct remain unclear, although strong aeration and turbulent water in the rearing containers were observed to be main factors enhancing normal inflation of the larval swim bladder. © 1979.