Chlorine dioxide is one of the most promising substitutes for chlorine. It is a strong oxidant that could be applied in a variety of seafood processes. An excellent sanitizer, chlorine dioxide has been shown to be seven times more potent than aqueous chlorine in killing bacteria and viruses in some applications. Furthermore, fewer potentially toxic reaction products result from treatment of organic matter with chlorine dioxide.
Since the bactericidal activity of chlorine dioxide is not affected by alkaline conditions and/or high levels of organic matter, it maintains bactericidal action far longer than chlorine. Chlorine dioxide is less reactive than aqueous chlorine in interactions with organic compounds such as unsaturated fatty acids, their methyl esters, and tryptophan and its derivatives. Consequently, fewer potentially toxic/mutagenic reaction products are formed.
When chlorine dioxide reacts with aqueous contaminants, it is usually reduced to chlorite ions. Chlorine dioxide-manufacturing systems are also easy to install, operate, and maintain.

Resources from: https://www.globalseafood.org