Gonad differentiation and body growth in Anguilla anguilla L.

Using histological sectons, the gonad of samples of yellow and silver els of two populations were examined. The populations were previously anlysed for growth and sex ratio. the histological structures observed are similar to those described in previous publications for the European eels, Anguilla amguilla and to those indicated for Pacific eel, A. japonica. well differentiated gonads are present in th esilver eels. In the yellow eels, ranging in age from 0+ to 2+ years and from a length of 20 cm to that at which they become silver, undifferentiatedand both sex gonads are found. Histological evidence is completely differentiatedat a veryearly stage. the testi-like gonad of the yellow eel is a more primitive. and possibly reversible, gonad which differentiatescompletely at the beginning of sexual maturation and the change to the silver phase

New developments in vertebrate cytotaxonomy III. Karyology of bony fishes: A review

[No abstract available