A comparative study of physiological, genetic and behavioural mechanisms involved in the sexual growth dimorphism of two teleost models : perch Perca fluviatilis L. and the Nile tilapia Oreochromis niloticus L

The main objective of this project is to characterize the sexual growth
dimorphism in two teleost fish, the Eurasian perch Perca fluviatilis and
the Nile tilapia Oreochromis niloticus, in terms of appearance period
and amplitude and environmental, social and physiological factors
involved in its determinism. This study will mainly determine the
influence of sexual steroids on somatic growth and energy allocation
over the different target organs as well as the action mode of the
steroids through the synthesis and/or release of growth and thyroid
hormones. The role of feeding behavior and social interactions, and the
influence of environmental factors involved in the control of
gametogenesis will also be investigated. Research will be conducted
with normal genotypes (XX females, XY males), but also with
individuals displaying dissociations between genotype and phenotype
(e.g. XX and YY males, XY and YY females), which will be obtained
from biomanipulated breeders.

1. Relationship between sexual maturation, reproductive endocrinology
and growth dimorphism

2. Mode of action of sexual steroids and assessment of an endocrine
relay.

3. Effects of feeding behavior and social interactions.