34 Charles S. Manooch, III and Diane L. Mason 



ted States. The yellowfin is the largest and more prized of the two, 

 attaining a weight of at least 176 kg (compared with 19 kg for blackfin). 



On the whole, tuna landings in the western Atlantic are sporadic 

 and are much smaller than those made by the large-scale, international 

 hook and line and seine tuna fisheries that operate in the eastern Atlan- 

 tic and Pacific. The total United States commercial landings of all tunas 

 was 341,149,000 pounds in 1981, 326,860,000 pounds from the Pacific 

 and 14,289,000 from the Atlantic. Only 131,000 pounds were landed in 

 the South Atlantic Region — North Carolina, South Carolina, Georgia, 

 and the east coast of Florida (D. S. Fitzsgibbon, pers. comm.). Of the 

 South Atlantic total, only 5,000 pounds were identified as yellowfin 

 tuna, and none as blackfin, although the 55,000 pounds of unclassified 

 tunas undoubtedly included blackfin. Recreational catches of yellowfin 

 and blackfin tunas tend to be greater than the commercial catches for 

 the southeastern United States. In North Carolina, for instance, anglers 

 fishing from charter boats in 1978 caught approximately 151,000 pounds 

 of yellowfin tuna and 38,000 pounds of blackfin tuna (Manooch et al., 

 1981). No information is available for 1981. 



Considering the disproportionately large commercial catch of tunas 

 in the Pacific, it is not surprising that many publications pertaining to 

 life histories, population dynamics and exploitation have resulted from 

 research on species in that region. Relatively few studies have been con- 

 ducted on Atlantic stocks. Dragovich (1969) in his review of food stud- 

 ies on Atlantic tunas mentioned that the papers he read emphasized 

 the need for additional research on the foods and feeding habits of 

 Atlantic stocks. The limited information available from the western 

 Atlantic usually resulted from fish collected aboard scientific vessels 

 that did not operate along the southeastern or Gulf coasts of the United 

 States, or that operated well offshore of the normal sport fishing 

 grounds (Dragovich 1969, 1970). 



To obtain more data pertinent to the management of pelagic 

 stocks, studies were initiated on oceanic species important to fisheries 

 along the southeastern and Gulf coasts of the United States. Our study 

 is the result of a cooperative effort that included the Oceanic Pelagic 

 Program, SEFC, Miami Laboratory, and the Bioprofiles Task, SEFC, 

 Panama City Laboratory. The objectives were to 1) identify the food 

 habits of yellowfin and blackfin tunas; 2) compare the diets of the spe- 

 cies collected from the same geographic area during the same period of 

 time; and 3) determine if changes in the diets occur for different sizes of 

 fish. 



METHODS 



Of the 206 yellowfin and 98 blackfin stomachs examined, 169 and 

 55, respectively, were from fish landed at Oregon Inlet or Hatteras, 



