Fig. 1
Reproductive parameters in Atlantic salmon male grilse during their first reproductive cycle. Gonadosomatic index (GSI; a plasma 11-ketotestosterone (11KT; b or testosterone (T; c levels (ng/ml plasma), and relative pituitary mRNA levels of fshb (d) or lhb (e) in male Atlantic salmon. Samples were collected over a period of 17 months during the first reproductive cycle of these 3 year old males (experiment 1). The animals were grouped according to the histological analysis of the most advanced germ cell stage found in the testis (Aund, type A undifferentiated spermatogonia; Adiff, type A differentiating spermatogonia; B, type B spermatogonia; SC/ST, spermatocytes/spermatids; SZ, spermatozoa). The number of individuals analyzed per group is given under the respective bars, showing group means and SEM. Bars sharing the same letter within a given graph are not significantly different (p < 0.05; one way ANOVA followed by SNK post hoc test)