Occurrence, Morphology, and Parasitism of Gastric Ulcers 



in Blue Marlin, Makaira nigricans, and Black Marlin, 



Mal^aira indica, from Hawaii 



ROBERT T. B. IVERSEN' and RICHARD R. KELLEY^ 



ABSTRACT 



Gastric ulcers were found in 10 of 114 blue marlin, Makaira nigricans, and 2 of 3 black marlin, M. 

 indica, examined from 1967 to 1969 at the Hawaiian International Bilinsh 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 ( 1968). Evans and Wares (1972). and 

 Iversen and Kelley (in press). We here report addi- 

 tional details on 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 an- 

 nual Hawaiian International Billfish Tournament. 



METHODS 



One hundred seventeen marlin were captured dur- 

 ing daytime trolling in surface or near surface waters 

 just off the west coast of the Island of Hawaii. Each 

 billfish tournament included 5 fishing days during 

 either July or August. Fishing commenced each day 

 at 0800, but the catch was usually not brought to the 

 weighing station until after 1700 when fishing ended, 

 so there often was a lengthy interval between cap- 

 ture and examination of the stomach. After being 

 weighed by tournament officials, each fish was 

 measured, sexed, and examined for stomach con- 

 tents. Specimens were not refrigerated prior to ex- 

 amination. The estimated maximum interval be- 



' Southwest Region, National Marine Fisheries Service. 

 NOAA. c/o Southwest Fisheries Center, Honolulu Laboratory. 

 National Marine Fisheries Service, Honolulu. HI 96812. 



- Department ot Pathology, Queens Medical Center, Hon- 

 olulu. HI 96813. 



tween capture and examination of marlin contain- 

 ing ulcers was 7.5 h. Histological preparations were 

 by standard paraffin imbedding with hematoxylin 

 and eosin stain. 



RESULTS 



Ten of 1 14 blue marlin and 2 of 3 black marlin 

 contained ulcers, for a combined occurrence of 

 10.3%. Sex, weight, and length for each marlin with 

 ulcers are given in Table 1. Two black marlin and 

 seven blue marlin stomachs with ulcers were pre- 

 served in 10% Formalin'* for laboratory examina- 

 tion. Two of the black marlin and one of the blue 

 marlin stomachs examined in the laboratory con- 

 tained ulcers invaded by small parasitic nematodes, 

 Contracaeciim sp.?, a roundworm which has been 

 reported in billfish stomachs from widely separated 

 localities (Wallace and Wallace, 1942; Morrow, 

 1952). 



The following brief comments on gross and mi- 

 croscopic morphology are based upon examination 

 of one of the black marlin stomachs which contained 

 numerous ulcers, both with and without nematodes. 

 The comments are also descriptive of ulcers in blue 

 marlin. 



Gross Findings 



The ulcers were either separate or in clusters 



' Reference to commercial products does not imply endorse- 

 ment by the National Marine Fisheries Service. 



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