Data from: 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 and size at maturation are positively correlated with fecundity
and egg size at the phenotypic level. Genetic correlations with growth are
positive for both egg size and fecundity, but weaker for egg size.
Contrarily, the environmental correlations with growth are of the opposite
sign, also weaker for egg size, and increasing growth leads to decreasing
egg size but increasing fecundity. Consequently, reproductive success can
be optimised across generations via independent selection responses of egg
size or fecundity and by correlated selection responses with body size.
Ultimately, the egg size-fecundity resource trade-off in Arctic charr is
resolved via growth-controlled phenotypic plasticity acting within
generations.