In both agriculture and aquaculture, the efficiency to grow a certain plant or animal is key not only in economics but in sustainability as well. One of the statistics that measures efficiency is feed conversion ratio (FCR), the ratio of how much feed is given to an animal compared to how much growth the animal obtains. For example, an FCR of 1 means that for every pound of feed given, the animal grows one pound. The closer the FCR is to 1, the more efficient and sustainable growing that animal is. Cows produced for beef have an FCR of around 6, meaning 6 pounds of food are required to add one pound of growth; chickens have an FCR of 1.6. However fish, and specifically Perciformes Sablefish, have an FCR of only 1.1! Growing fish in recirculating aquaculture systems is one of the most sustainable and efficient production methods for livestock.