Why does vertical distribution matter?
§ Vertical distribution determines
transport trajectories on the Bank:
copepods in the surface waters (0- 15
m) are advected by Eckman transport.
§ Copepods below the Eckman layer are
less subject to transport.  The tidal
mixing front may help retain deeper-
dwelling copepods on the Bank.
§ Remaining deeper in the water column
may represent a strategy to aid
retention and avoid loss from Georges
Bank for small copepods like
Pseudocalanus spp.
   Chen et al. (2003) modeled particle
transport on Georges Bank, showing
distributions of particles at model days
16.5, 18.5, and 19.7 for the case with
tidal forcing plus realistic wind stress.