Get a gallon milk jug, or similar container and cut a big enough hole to reach into, but not so big that water splashes out easily. Pour in 1/2 gallon of saltwater, 1 1/2 cups of canning salt, toss in your herring the night before, and fish 'em the next day. I have only used fresh herring once this year, and we have brought close to 200 salmon to the boat this year. Frozen is cheap, and readily available, so don't worry too much about not getting fresh.

I go through so much that I haven't had any on hand for more than a day and a half, but I have had extra from the last day of a trip, neatly packaged the herring, and then froze it without any issues. it is alwasy the first herring I use the next time out.

Hope this helps.

Andy