First, as a professional, I can give you a way to determine what is needed, but, keep in mind that this is just one meal. : 1/2 a pound for each and every adult, and half that for a child or an elderly person. The next point is this. Our fish contains mercury and other pollutants which restrict how much should be consumed weekly. Bottom fish tend to harbor more pollutants, but even popular fish species like tuna and salmon also have amounts of pollutants. The building of dams and locks can further inhibit salmon spawns and causes other invironmental problems concerning river and ocean fish species. The appearance of oceanic "dead zones", areas where the oxygen has been totally depleted, are generally thought to be connected to commercial fishing endeavors which has done massive damage to the ecosys, including destruction of coral reefs. These are some problems about sustainable fish stocks. The damage may have already passed a tipping point. With the reality of global warming, the oceanic stocks are in grave peril, because of the huge increase of fresh water being released from glacial melt. As anyone who has ever had a tank of salt water fish could tell you, too much imbalbalance in the ocean will kill everything.