[613458]

Be certain that the slurry is saltwater based, not fresh water. The ice will naturally melt a little in the saltwater because the freezing temperature will be lowered, but you will still have a fairly saline solution. What you don't want is a freshwater bath. The tissue of the fish will absorb less saline water, necessarily effecting the quality of the meat.

 

[613458]

Kosher Salt is non-iodized and won't turn the color of the flesh.

"Prolonged high temperature is the most important factor influencing quality and spoilage rates. Rapid chilling and freezing are crucial for maintaining high quality fish. Both enzymatic reaction rates and bacterial growth rates are greatly influenced by temperature. Both processes are very active above 30 F. Even minor changes in the temperature range of 30 F to 50 F have enormous effects on the growth of bacteria. Seafood spoilage is 4 times faster at 50 F than at 30 F and 2.2 times faster at 40 F than at 30 F. Even though bacteria and enzymatic activities have slow substantially at 30 F, they do not stop; thus tuna should be frozen quickly to below 10 F to halt these activities." That's why, if at all practical, the best manner of preserving fish is to pack it wrapped and placed in dry ice rather than plain ice.