Data from: Spatial structuring and life history connectivity of Antarctic silverfish along the southern continental shelf of the Weddell Sea

A multidisciplinary approach was employed to examine a physical-biological
population hypothesis for a critical forage species, the Antarctic
silverfish (Pleuragramma antarctica). A previous study had shown strong
gene flow along the westward Antarctic Slope Current, in addition to
spatially recurring length modes that provided evidence for episodic
connectivity. In this paper, otolith nucleus chemistry from a subset of
fish collected in the southern Weddell Sea as part of a hydrographic
survey of the Filchner Trough system was used to test between connectivity
scenarios. Nucleus chemistry, which reflects environmental exposure during
early life, showed significant spatial structuring despite homogeneity in
microsatellite allele frequencies. Mg×Ca-1 and Sr×Ca-1 differentiated
length modes, and Mg×Ca-1 showed significant contrasts between Atka Bay,
Halley Bay, and Filchner Trough. Physical-biological mechanisms may help
reconcile structuring shown by otolith chemistry, length, and abundance
data with prior evidence of gene flow. Such mechanisms include
self-recruitment shaped by circulation associated with the Filchner
Trough, fluctuations in mixing between immigrant and locally-recruited
fish, and feeding opportunities between inflowing Modified Warm Deep Water
and outflowing Ice Shelf Water. The results illustrate how comparisons
between multi-disciplinary techniques based on integrated sampling designs
that incorporate hydrography can enhance understanding of population
structure and connectivity around the Southern Ocean.