Rockhopper -
Actually sea-runs eat quite a few amphipods (sand fleas) in the salt. Thye look very similar to the freshwater scuds that you are familar. They are dark olive and typically size 12 or so.

The down side in fishing them is that they work best on a slow strip. Not the best way to cover water to find fish - streamers are more effective as a rule. Suspect that the scuds would be a ncie backup for fish that are being picky.

Tight lines
S malma