Edited sentence: A 2007 study of blue marlin stomach contents carried out by Japanese scientists on fish captured in a commercial trolling fishery found that 130 undigested prey items obtained from 227 blue marlin had spearing, slashing and other injuries that were judged to have been inflicted by the bill.As larvae, blue marlin feed upon a variety of zooplankton, including fish eggs and larvae drifting in the pelagic environment.As they grow larger they progress to feeding on a wide range of fishes, particularly scombrids such as mackerel and tuna; squid; and also, especially near oceanic islands and reefs, on juvenile inshore fish.Conversely, they are also capable of feeding on small but numerous prey such as filefish and snipefish.Diet and feeding.Growth and maturity.Large blue marlin have been recorded as taking prey as large as white marlin as large as 72 inches, as well as yellowfin and bigeye tuna in the 100 lb class.Scientists and fishermen have long debated the extent to which blue marlin and other billfish use their elongated upper jaw in feeding.Studies of blue marlin stomach contents in both the Atlantic and Pacific have found that smaller schooling scombrids such as frigate mackerel, bullet tuna and skipjack tuna make up a substantial proportion of their diet; squid, including the large Humboldt squid, and deep-sea fishes such as pomfret and snake mackerel, are also important prey items in certain areas