Aluminium accumulation on eggs and hatching system during the incubation period - an important cause of variable hatching success ?

Abstract

Groups of rainbow trout eggs were incubated in duplicate in trays with PVC screens and original aluminium screens. During incubation aluminium bound to sediments was deposited on eggs and hatching systems. By adding acid the pH of the inlet water to a PVC hatching system with sediments from the hatchery water in it, was experimentaly lowered. Buffering of the outlet water was observed from pH 5.0 and lower, and at pH 4.5 and lower an increase of aluminium concentration in outlet water was measured. If a variable pH of the hatchery water is to be expected, the aluminiumrich sediments deposited on eggs and hatching system during incubation may represent a threat to the survival of eggs and fry.