Seawater is known to contain a significant concentration of boric acid, which can be toxic and deadly to living systems. As such, fish living in marine habitats need to be able to excrete boric acid in order to maintain a healthy boron balance. Researchers have now identified the gene and mechanism of boric acid transport in seawater fish and contrasted it to freshwater species.Seawater is known to contain a significant concentration of boric acid, which can be toxic and deadly to living systems. As such, fish living in marine habitats need to be able to excrete boric acid in order to maintain a healthy boron balance. Researchers have now identified the gene and mechanism of boric acid transport in seawater fish and contrasted it to freshwater species.