Food Quality and Life-History Genotype Influence Maturation and Reproductive Traits in Female Atlantic Salmon

Area of Science:

• * Life-history evolution
• * Aquatic ecology
• * Animal genetics

Background:

• * Age at maturity is a crucial life-history trait with significant sex-specific variation in many species.
• * Atlantic salmon (Salmo salar) exhibit sex-specific maturation patterns, making them a valuable model for studying underlying factors.
• * Research on female salmon maturation is less common due to their later average maturation age compared to males.

Purpose of the Study:

• * To investigate the influence of diet and the vgll3 gene on female Atlantic salmon maturation.
• * To assess the impact of genetic and environmental factors on maturation-related phenotypic traits.
• * To understand the interplay between population origin, diet, and body condition in influencing maturation timing.

Main Methods:

• * A 4-year common-garden experiment involving female Atlantic salmon from two distinct hatchery populations.
• * Controlled dietary conditions: low-fat versus control diets.
• * Analysis of maturation probability, heritability, gene (vgll3) contribution, and body condition in relation to environmental factors.

Main Results:

• * The early-maturation associated E allele of vgll3 was additively linked to an increased probability of maturation.
• * Heritability of maturation was estimated at 0.295, with vgll3 accounting for approximately 2% of phenotypic variance.
• * Body condition, influenced by population and diet, significantly affected maturation; northern populations and low-fat diets correlated with lower body condition.

Conclusions:

• * Both genetic factors (vgll3 gene) and environmental influences (diet, population origin) play a significant role in determining age at maturity in female Atlantic salmon.
• * Population-specific responses to diet highlight the complex interactions between environment and life-history traits.
• * The study enhances understanding of the mechanisms driving sex- and population-specific maturation in species with variable maturation timing.