Occurrence, Morphology, and Parasitism of Gastric Ulcers in Blue Marlin, Makaira

Gastric ulcers were found in 10 of 114 blue marlin, Mu&uim nigricuns, and 2 of 3 black marlin, M. indica, examined from 1%7 to 1969 at the Hawaiian International Billfmh Tournament. Parasitic nematodes were found imbedded in the base of ulcers in one blue marlin and two black marlin. The gross and microscopic morphology of the ulcers is given and possible causes are discussed. The most likely cause is either mechanical injury or parasites, or the effect of both in the same stomach. The existence of gastric ulcers in man and other mammals, including marine mammals (Geraci and Gerstmann, 1966) is well known. The existence of gastric ulcers in fish was first noted by Aliverdiev and Radzhabov (I%@, Evans and Wares (1972). and Iversen and Kelley (in press). We here report additional details o n the occurrence, morphology, parasitism, and possible causes of gastric ulcers in blue marlin, Makaira nigricans, and black marlin, M . indica, landed from 1967 to 1969 during the annual Hawaiian International Billfish Tournament.