A second use is due to fish cropping. Think of your favorite fish, many would say tuna, swordfish, and trout. All these species are carnivorous in the. All of options farmed. Tuna in particular requires quite a bit of sardines - http://www.recruitingblogs.com/main/search/search?q=sardines to be captured. It's one of your major drawbacks of fish farming. Together with algae farming we can make an artificial food archipelago. I'm not suggesting this particular is a panacea for your ills of fish plants - http://www.lifebeyondtourism.org/?header_search=fish%20plants .