Fishing down the food web — the idea that fishermen target the largest species, then smaller, then the forage fish, until eventually the oceans have nothing but jellyfish, is a cornerstone belief of many environmentalists concerned about overfishing.
[But] a new study, published in a Canadian Journal, has debunked this theory, and shown that over 112 years in the N. Pacific, there is no evidence for fishing down the food web, and in fact the average tropic level of target species appears to have increased. Read the full analysis in John Sackton’s Winding Glass blog