Sardines are nutrient-rich, small, oily fish widely consumed by humans and as forage fish by larger fish species, seabirds, and marine mammals. and they are one of the most popular seafood in the world due to their incredible taste and its reasonable price. They provide 2 grams of heart-healthy omega-3s per 3 ounces serving, which is one of the highest levels of omega-3 and the lowest levels of mercury of any fish. Also, this fish contains a huge source of calcium and Vitamin D, so they support bone health, too. Canned sardines are a little salty, though far less salty than anchovies or herring.