Is the Spear of Istiophorid Fishes Used in Feeding ? 1 
Robert L. Wisner 2 
The sport of angling for spearfishes— the 
several marlins and sailfishes of the family 
Istiophoridae — has fostered many books and 
articles on the behavior of these large fishes. 
The swordfish, Xiphius gladius Linnaeus, com- 
prising the family Xiphiidae, also commands 
a very considerable following among salt- 
water anglers and is the subject of an ex- 
tensive literature. Certain beliefs have arisen 
concerning the behavior and habits of the 
fishes comprising these game fish families, 
particularly as to their methods of obtaining 
food. It seems worthwhile to attempt now an 
evaluation of the accumulated evidence. Only 
the true spearfishes, particularly the marlins, 
will be considered in detail. The broadbill 
swordfish will be mentioned only occasion- 
ally, and the conclusions reached do not nec- 
essarily pertain to this fish. 
Angling lore is replete with reports of such 
fishes stunning prey and trolled fish baits with 
a blow of the spear before devouring them. 
The time-honored belief that the spearfishes 
possess their spears for the express purpose 
of striking or stabbing prey, however, may 
now be questioned. Recently accumulated 
evidence indicates that such fish can exist 
quite readily without a spear to aid in obtain- 
ing food. Other evidence has cast some doubt 
as to whether the spear is at all commonly 
employed in such a manner. 
1 Contributions from the Scripps Institution of 
Oceanography, New Series, No. 958. Manuscript re- 
ceived March 27, 1956. 
2 Scripps Institution of Oceanography, University 
of California, La Jolla, California. 
RECORDED OBSERVATIONS OF FISH 
WITHOUT SPEARS 
Moore (1950) reported on a spearless black 
marlin, Makaira mazara (Jordan and Sny- 
der), that was landed at a commercial fish 
market in Honolulu, Hawaii, without indi- 
cating the length of stub remaining. The na- 
ture of the wound indicated some time lapse 
since the loss. The specimen weighed 545 lbs. 
and was judged equal in physical condition 
to normal fish of the same species. 
Mr. Vernon E. Brock, Director, Division 
of Fish and Game, Hawaii, in correspondence 
reports ”... a spear removed from a marlin 
which has been broken with the remaining 
part that is spiraled like a corkscrew. The fish 
from which the spear was taken was, accord- 
ing to the fishermen, normal in all respects.” 
Morrow (1951) reported that a 172-lb. 
striped marlin, Makaira mitsukurii (Jordan 
and Snyder), taken with sporting tackle and 
trolled bait at Otehei Bay, New Zealand, had 
the spear broken off on a long slant reaching 
from several inches behind the mandible tip 
to within a few inches of the eye. The break 
had completely healed and was well covered 
with skin. The injury had affected the fish 
further in that the mouth was prevented from 
closing completely, one side remaining partly 
open. However, the fish appeared to have had 
no difficulty in taking the bait and gave a 
battle said to have been entirely normal for a 
fish of its weight. 
Farrington (1942: 110) reported numbers 
of marlin with spears broken off. This obser- 
vation was made at Guaymas, Sonora, Mex- 
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