Life history implications of kinship structure in an Atlantic Herring schooling aggregation

Kinship in natural marine fish systems has been little explored in part due to costs of genomic analysis. This is especially true for very abundant and commercially exploited marine fish with broadcast spawning. Recent advances in genomics have however, facilitated an improved understanding of population structure in marine systems at fine geographic scales. Here, we identify kinship structure in an aggregation of Atlantic Herring (Clupea harengus) juveniles. We identified 11 and potentially up to 14 half-sib pairs using a suite of 92 sequenced microsatellite DNA markers and the R package CKMRsim in a sample of N=1391 herring individuals comprising two cohorts (ages 0+ and 1+) collected from the 2018 Fall research survey of the Southern Gulf of St. Lawrence. We also discuss the detection of potential full-sibs in the data by way of association from the half-sib pairs. This study suggests the presence of kinship structure in a juvenile herring aggregation three months or more post hatching with implication for our understanding of herring early life history.

Methods
Unprocessed microsatellite data from Atlantic herring tissue samples from Gulf of St. Lawrence collected in 2018. DNA extraction was done using Glassmilk protocol and sequenced on Illumina HiSeq 2500 - High Throughput for 92 microsatellite markers on 1391 individuals (980 Age 0+ and 411 Age 1+).