u 

 o 



UJ 



Q. 



30-1 



20- 



10- 



30n 



20- M 



10- 



20-1 D 



lo- 



se -I 



20- 



10- 



N =61 

 X =172.2 



30-1 



20- 



10- 



T — I — r 



T 1 1 1 1 1 



"1 c 



0-S — 1—1—^ 1 



1 — I — I — I 



Figure 2— Length frequencies of sailfish captured by the 

 Japanese longline fishery in the Atlantic, 1975-76. Letters indi- 

 cate areas from Figure 1. 



agree quite well with similar data on eastern At- 

 lantic specimens sampled off the coast of Africa, 

 both in range and average length. Additionally, 

 size frequencies of sailfish from the East China 

 Sea (Koto et al. 1959) are quite similar to size data 

 for western Atlantic sailfish given by Jolley (1977). 

 In both the eastern Pacific and eastern Atlantic, 

 sailfish occur in an area where a substantial sur- 

 face fishery for yellow^n and skipjack tunas takes 

 place. Fox^, in his analysis of the temporal and 

 spatial relationships among tunas and billfishes 

 in the Atlantic, showed a strong correlation be- 

 tween the occurrence of sailfish and yellowfin tuna 

 in the Atlantic and a strong relationship between 

 the occurrence of the two species and surface 

 water temperatures. 



There are also similarities in the environment 

 on the eastern sides of the Atlantic and Pacific 

 Oceans where the largest specimens of sailfish 

 occur. Both areas have relatively shallow thermo- 

 clines. Thermal domes occur in both the eastern 

 Atlantic (Mazeika 1967) and the eastern Pacific 

 ( Wyrtki 1964) and probably influence the season- 

 al distribution of at least some oceanic fishes 

 (Beardsley 1969). 



It seems possible, therefore, that environmental 

 conditions in both the eastern Pacific and eastern 

 Atlantic favor rapid growth and the attainment of 

 a large size in sailfish. 



There is also the possibility that the group of 

 large sailfish off Africa are immigrants from the 

 Indian Ocean around the tip of South Africa. 

 Other large oceanic fishes, such as the albacore, 

 Thunnus alalunga, and the black marlin, Makaira 

 indica, are suspected to have entered the Atlantic 

 by this route (Koto 1969; Wise and Davis 1973), 

 and Penrith and Cram (1974) reported that six 

 species of billfishes have been recorded in waters 

 west and south of the Cape of Good Hope. The 

 sailfish, however, was not included in this group. 

 Even though Penrith and Cram did not find 

 sailfish in their samples, the presence of other 

 istiophorids suggests that sailfish probably are 

 present at times in this area. 



The sizes of sailfish from the eastern Atlantic 

 and the western Indian Ocean are similar. Merrett 



EYE-FORK LENGTH, CM 



^Fox,W. W., Jr. 197L Temporal-spatial relationships among 

 tunas and billfishes based on the Japanese longline fishery in the 

 Atlantic Ocean, 1956-1965. Univ. Miami Sea Grant Tech. Bull. 

 12, 78 p. 



807 



