edit:  oops, I didn't see your attachment and answered the wrong question, talking about the narrow gap with current wehre Batch empties into Pickeral L, so I erased my answer.  I wouldn't call that Batch to Pickeral Narrows, but Batch to Batch Bay - guess it may depend on which maps you are looking at

where you have the pink arrow ? I assume - that seems like a mile of portage to avoid maybe 3 miles of paddling - not sure many people would opt for that, so it likely is no longer used if it ever was.

If it is a current "official" portage (i.e. they will clear it every few years at least), it would be shown on the Chrismar park map - I'll look at that when I get home if you don't get a better answer in the meantime.