Methyl Mercury is the most toxic form of mecury to humans and the environment. Methyl mercury is a form of mercury that is converted by bacteria and organic materials. Mercury that gets into the Bay is often changed into methyl mercury in the shallow waters and ends up being ingested by plankton, microscopic animal and planet life used as food by nearly all aquatic animals. Larger fish feed ont he plankton and methyl mercury becomes concentrated in predatory fish's flesh through a process of bioaccumulation.