There are two distinct size and spawn date peaks in age-0 (juveniles) collected in 2021 - big fish that were spawned in the winter, and little fish that were spawned in the spring. We already have genetic data for 53 of the biggest/littlest fish from that year (14x coverage) which shows two distinct clusters, which are associated with spawn timing (Winter: January/February, or Spring: March/April).

One question is, are the fish in the left/small fish cluster (n=12) siblings? They cluster together tightly. I conducted kinship analysis using ngsrelate. This calculates pairwise kinship stats for fish pairs. I then looked at the distribution of these stats by fish pairs that were both spawned in the spring, those that were both spawned in the winter, and compared those to fish pairs that were spawned in different seasons (as a control).

Across the board “rab” (relatedness estimate) suggests that all fish could actually be half-sibs or possibly cousins(?) which is suspect since many are spawned four months apart. However, I have not removed linked sites so this could be elevating our results (as per Laura Timm). Good news is that spring-spawned fish do NOT appear to be full-sibs. However, the distributions of relatedness and more interestingly inbreeding stats are different in spring-spawned fish - they are on average higher than the winter-spawned fish - indicating that they are more related to each other. There may also be evidence of inbreeding in the spring-spawned fish that could be influencing relatedness. Weird! This could mean that the genetic patterns are related to the adult spawning behavior & breeding, rather than little and big fish representing random cohorts that happen to move together / be sampled together. Below are distributions of those pairwise kinship/inbreeding stats. More figures/notebook writeup are here.