Fish is a great source of low-fat protein and vitamins.
Unfortunately, eating large quantities of fish may be unhealthy, especially for a developing fetus, because many fish are contaminated with mercury. Mercury is a neurotoxin that can cause developmental problems. There is also evidence that mercury may be harmful to loons, otters and other fish-eating wildlife. A small percentage of mercury that reaches lakes is emitted by natural sources such as volcanoes. Some mercury is emitted by coal-fired power plants and other processes that heat large quantities of raw materials containing low levels of mercury.