It's been said that as wild and readily-available supplies of everyday market fish like salmon, cod and halibut are depleted -- and the upper reaches of the marine food chain is removed -- we'll have to start eating our way down the food chain. It doesn't get much lower than jellyfish (already a delicacy in certain parts of Asia), which are becoming more and more plentiful as their predators disappear and excess nutrients from agricultural runoff makes it way into the oceans. Turns out that jellyfish explosions are becoming an epidemic in the Black Sea, ever since the mackerel population was overfished in the 1960s and 70s; now jellies can multiply with unchecked abandon, fed by animal waste and fertilizer runoff from farms. Thanks to EnglishRussia for the gross pictures: