Herring in Bucket Question

I've heard it helps if the water is kept very cold by putting some ice cubes in it to slow the metabolism of the herring. Would guess same concept as making sure the bubbler system you're using is insulated. I know it works keeping other bait fish alive, have heard it helps with herring as well. Coool water, well oxygenated and a circular bucket or tank for them to swim. All contriubutes.