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.
Chen et al. (2003) J. Geophys. Res. 108