the blade being your only real concern; yes, S30V and BG42 both will develop spot rust with saltwater exposure, but its easily remedied.
Titanium and 303 stainless (the Seb's handles and hardware) are mainstays around saltwater anyway these days. All you need to do, even if you completely immerse your Sebenza in salt water, is to dunk it in fresh water as soon after as possible. A sink would be even better. Then, after the trip when you're gear is stowed and you've cleaned your catch, break your Sebenza completely down and clean it. A toothbrush with a little Flitz or Brasso does wonders for spot-rust removal on the blade's surface and within the thumb ridges, if any, but careful around the thumblug(s)*, as any mild abrasive will gradually wear the color off. Clean thoroughly with paper towels, lube, and you're right as rain.
In one sense, the Sebenza is truly better suited to saltwater use than most other folders, in that the blade is its only real rust target, and it can be broken down so easily.
*Any civilized person should have double thumblugs

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Professor.