Originally Posted by
hogdog
You are right about the sardines. Sardines are low on the oceanic food chain, and therefore contain low amounts of mercury, PCBs and the other toxins that accumulate in longer-living marine predators such as salmon and tuna. Mackerel is very high in mercury. I dont have the time to elaborate on the negative effects of mercury but just google it and youll see why it would be foolish to feed something high in mercury to working animals when there is a healthier alternative.