Data from: Natal philopatry increases relatedness within groups of coral reef cardinalfish

A central issue in evolutionary ecology is how patterns of dispersal
influence patterns of relatedness in populations. In terrestrial
organisms, limited dispersal of offspring leads to groups of related
individuals. In contrast, for most marine organisms, larval dispersal in
open waters is thought to minimise kin associations within populations.
However, recent molecular evidence and theoretical approaches have shown
that limited dispersal, sibling cohesion, and/or differential reproductive
success can lead to kin-association and elevated relatedness. Here, we
tested the hypothesis that limited dispersal explains small-scale patterns
of relatedness in the pajama cardinalfish Sphaeramia nematoptera.
We used 19 microsatellite markers to assess parentage of 233 juveniles and
pairwise relatedness among 527 individuals from 41 groups in Kimbe Bay,
Papua New Guinea. Our findings support three predictions of the limited
dispersal hypothesis: 1) Elevated relatedness within groups, compared to
among groups, and elevated relatedness within reefs compared to among
reefs; 2) A weak negative correlation of relatedness with distance; 3)
More juveniles than would be expected by chance in the same group and the
same reef as their parents. We provide the first example for natal
philopatry at the group level causing small-scale patterns of genetic
relatedness in a marine fish.