Is it better to freeze herring covered in brined water or to brine them after they thaw back out? Thanks

Brine'em first. Brining takes some of the water out. That increases the durability of the herring once it's thawed.

It has been my experience that when I brine frozen herring they hold up much better than when I brine fresh herring but they are normaly commerialy available frozen herring. I have also frozen left over fresh herring and dipped them in iced water refroze them and so on many times so as to icicle them and treated like that they hold up very well in the freezer.

Starting with fresh herring; usually I jig my own, I have had the best luck plug cutting them immediately and placing in a cold brine (salt, powdered milk and bluing) for up to 6 hours (I use frozen sea water to cool the brine). If you have the space it works well to keep the brine and herring in the freezer; a strong brine will not freeze in the normal home freezer.

However usually I have limited space so I remove the cut plugs from the brine and roll them in borax (the same I used to use for curing eggs). I put the boraxed cut plugs in freezer bags with extra borax. I usually put a dozen/bag. Have had good luck I keeping boraxed for up to month and have found they fish very well; typically the borax cut plugs fish with freshly jigged bait fish for fish.

If on a fishing trip the cut plugs treated with borax will keep and fish well for several days without freezing.

Curt