Life history implications of kinship structure in an Atlantic herring aggregation

Kinship in natural marine fish systems has been little explored especially 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 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 discuss the detection of three potential full-sibs in the data by way of association where two individuals are half-sibs to a third but not to each other. This putative full-sib pair was detected in the kinship analysis albeit outside the significance threshold used ( λ* = 12). This study suggests the presence of kinship structure in a juvenile herring aggregation 3 months or more post hatching with implications for our understanding of herring early life history.