FOCI scientists have shown that the timing and location of hatching determines
whether walleye pollock larvae enter an eddy
or are transported with either the slow-moving coastal flow or the rapid
ACC. The phasing between biological and physical processes determines transport
of larvae and their eventual recruitment. The location of eddy formation
coincides 
with
the spawning region. Formation of three to four eddies each month during
spring assures that some eggs hatch in an eddy. As a result of lack of dispersion,
high abundances of larvae often occur in eddies. Some eddies tend to remain
nearly stationary for weeks and help retain larvae on the shelf. The integration
of wind 
mixing, stratification within an eddy, and
larval behavior is important to the subsequent survival of walleye pollock
larvae.
Field observations have revealed a connection between eddies and larvae. Contours of larval abundance coincide with those of salinity and lie in close proximity to buoy trajectories. Physical data show minimal exchange of water between eddies and adjacent waters, permitting estimates of mortality that reflect only predation and/or starvation. Mortality rates are low in eddies compared with mortality rates in other areas and in model simulations.