120 
PACIFIC SCIENCE, Vol. II, April, 1948 
cific or only racial, must await examination of 
a series from the type locality. This fish was 
described from Hawaii by Jordan and Ever- 
mann (1926) as Neothunnus itosibi. Nichols 
and La Monte (1941) state that "at a weight of 
around 100 pounds the fin lobes . . . from the 
tropical Pacific compare in development with 
the maximum obtained by the Common Yellow- 
fin. At about 4 feet 5 to 9 inches, weighing 140 
pounds or less, the lobes are contained 2.1 to 
2.8 times in standard length . . .” These anal 
and second dorsal fins seem to be significantly 
longer than we would expect to find in N. 
macropterus, from Costa Rica at least. How¬ 
ever, it is also possible that the variability of 
fin length is greater among the members of the 
Hawaiian stock. Godsil and Byers’ Hawaiian 
specimens do not help with the solution of this 
problem since they were of very small size, 
537-573 mm. 
It is of interest to note that Frade (1931) 
has found that in the vicinity of Portugal there 
exist for the same size two types of N. alb ac or a: 
". . . comme pour N. macropterus du Pacifique, 
il existe pour la meme taille deux types de 
N. albacora: l’un a 2 e dorsale et anales longues, 
correspondant a N. macropterus forma itosibi 
et 1’autre a 2 e dorsale et anales courtes, cor¬ 
respondant a N. macropterus forma macrop- 
terus.” 
Beebe and Tee-Van (1936) consider that 
". . . the various nominal forms of the yellow- 
finned tuna belong to the same species, and that 
the forms typified by the large Allison’s tuna 
represent but large-finned specimens of the 
smaller short-finned individuals.” Walford 
(1937) found that among yellowfin tunas ex¬ 
amined in California canneries . . the dorsal 
and anal fins were of all lengths, intergrading to 
such an extent that it is impossible to separate 
them into two groups. In general, the largest, 
consequently the oldest fish had the longest 
fins.” 
It seems well established that wherever yel¬ 
lowfin tuna occur, both short-finned and long- 
finned individuals are encountered, and that this 
character is correlated with the size of the fish. 
Whether racial differences in the regressions of 
fin length on fish size will be found between 
localities we cannot say at this stage of our 
knowledge. Within the Costa Rican stock, how¬ 
ever, as represented by the present sample, there 
seems to be but a single race of yellowfin tuna. 
REFERENCES 
Beebe, William, and John Tee-Van. 1936. 
Systematic notes on Bermudian and West 
Indian tunas of the genera Parathunnus and 
Neothunnus. Zoologica [New York] 21 (14): 
177-194. 
Fisher, R. A. 1934. Statistical methods for re¬ 
search workers. Ed. 5, xii-f- 319 p. Oliver & 
Boyd, London. 
Frade, F. 1929. Sur quelques thons peu connus 
de l’Atlantique. Soc. Portug. de Sci. Nat. Bui. 
10(20): 227-234. 
---— 1931. Donees biometriques sur trois 
especes de thons de l’Atlantique orientale. 
Cons. Perm. Int. pour VFxplor. de la Mer, 
Rapp, et Proc.-Verb. 70: 117-126. 
Godsil, H. C, and R. D. Byers. 1944. A sys¬ 
tematic study of the Pacific tunas. Calif. Div. 
Fish and Game, Fish. Bui. 60: 1-131. 
Jordan, D. S., and B. W. Evermann. 1926. 
A review of the giant mackerel-like fishes, 
tunnies, spearfishes and swordfishes. Calif. 
Acad. Sci., Occas. Papers 12: 1-113. 
Kishinouye, K. 1923. Contributions to the 
comparative study of the so-called scombroid 
fishes. Tokyo Imp. Unin., Col. Agr. Jour. 
8(3): 293-475. 
Nichols, J. T., and F. R. La Monte. 1941. 
Yellowfin, Allison’s and related tunas. Ichthy. 
Contrib. Int. Game Fish Assoc. 1(3): 27-32. 
Walford, L. 1937. Marine game fishes of the 
Pacific Coast from Alaska to the equator. 
xxix-f- 205 p., 69 pi. Univ. California Press, 
Berkeley. 
