Structural and mechanical changes in the egg membranes of Salmo gairdneri Rich. during the period of hatching of the larvae

Abstract

Structural and mechanical properties of the egg membranes of Salmo gairdneri Rich. in the period of hatching were investigated. Only local action of hatching enzyme upon the egg membrane and local decrease of its strength was observed. In the places, which were not under the action of the enzyme, egg shell keeps its structure unchanged as well as its great strength. The differences in the thickness of egg shells of the same female and even of the same egg were observed. No correlation between the thickness of the egg shell and its strength was found.