Genetic and environmental (co)variation of egg size, fecundity, and growth traits in Arctic charr

Egg size and fecundity are both positively associated with maternal reproductive success, yet maternal resource limitations result in a trade-off between these two traits. Exploring this trade-off, the extent of genetic and environmental influences on egg size and fecundity, and of correlations between these and other traits, and thus the effects acting within vs. among generations, is therefore a central goal in both evolutionary ecology and selective breeding. Using multi-generational captive Arctic charr (Salvelinus alpinus) records, we quantified genetic and environmental effects on, and correlations between, egg size and fecundity, body size (a proxy for growth) and condition prior to maturation, and body size at maturation. We estimated that genetic contributions to variation in egg size and fecundity are moderate to high. Egg size and fecundity do not significantly correlate at the genetic level but do correlate negatively at the environmental level. Growth prior to maturation an..., , # Genetic and environmental (co)variation of egg size, fecundity, and growth traits in Arctic charr

Egg size and fecundity both enhance reproductive success but are limited by a trade-off. Using multi-generational Arctic charr data, we found moderate-to-high genetic effects, with no genetic correlation but a negative environmental correlation between egg size and fecundity. Growth traits correlated positively with each trait phenotypically, though genetic and environmental correlations differed. This suggests the trade-off is resolved by growth-mediated plasticity within generations, enabling flexible selection on reproductive traits.

#### Description of the data and file structure

The dataset consists of a Data.csv which has the following variables:

* Cohort: Cohort ID that corresponds to the year of fertilisation

- Number: Individual ID

* Dam: Dam ID

- Sire: Sire ID

* Cohort.Sib: Family ID

- YearStationID: Common environment ID that corresponds to the growing environment unti...,