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Figure 1. — Localities of collection of skipjack tuna ovaries in the eastern tropical Atlantic. 



COLLECTION AND CLASSIFICATION OF 

 SKIPJACK TUNA OVARIES 



Skipjack tuna ovaries were collected from 

 the eastern tropical Atlantic (fig. 1), western 

 tropical Atlantic (fig. 2), and near 40°00' N., 

 72°00' W. (about 100 km. off New York). The 

 tuna were captured on 9 cruises of three re- 

 search vessels, and 12 cruises of nine com- 

 mercial fishing vessels, from February 1964 

 through June 1967. 



In the eastern tropical Atlantic, ovaries 

 were collected from skipjack tuna from 47 

 fishing sites. The tuna were collected on three 

 cruises of the BCF (Bureau of Commercial 

 Fisheries) research vessel Geronimo-- Feb- 

 ruary to April and August to October 1964, 

 and February to March 1965. The procedure 

 was to catch 25 tunas from each school en- 

 countered, then record the fork length, weight, 

 and sex of each fish. Stomachs and ovaries 

 were removed and frozen (Sund and Richards, 

 1967). Skipjack tuna were also captured by the 

 commercial fishing vessels Kuroshio Maru 71, 

 72, 73, 75, and 76 from September 1965 to 

 January 1966. These fish were sampled in 

 Tema, Ghana; the lengths were recorded, and 

 the stomachs and gonads were removed, pre- 



served in Formalin, 1 and shipped to the BCF 

 Tropical Atlantic Biological Laboratory, 

 Miami, Fla. 



In the western tropical Atlantic, ovaries 

 from 170 tunas at 30 fishing sites were col- 

 lected in 1965-67 on two cruises of the 

 Geronimo , three cruises of the Undaunted , 

 and one cruise of the Oregon . Fishing loca- 

 tions of the Oregon are not shown in figure 2 

 because exact catch positions were not avail- 

 able; they are combined as one fishing site 

 that extends along the island banks from the 

 U.S. Virgin Islands to the northern banks of 

 Montserrat, British West Indies. Periods dur- 

 ing which ovaries were collected by the dif- 

 ferent vessels were: Geronimo --August to 

 October 1965 and February to April 1966; 

 Undaunted - -February to April 1966, Novem- 

 ber 1966, and February to March 1967; and 

 Oregon -- June 1967. Sampling procedures 

 aboard the Geronimo and Undaunted were the 

 same as those used during the Geronimo 

 cruises in the eastern tropical Atlantic. The 

 Oregon's procedures differed--skipjack tunas 

 collected were frozen and shipped intact to 



References to trade names in this publication do not 

 imply endorsement of commercial products. 



