Istiophorid Fishes — WiSNER 
67 
sufficiently rapid to strike a small fish fleeing 
for its life. Such great expenditure of energy 
would detract from the forward speed of the 
spearfish, bringing it to a virtual standstill and 
allowing the prey to escape with but little 
damage. 
It is more reasonable to assume that when a 
spearfish charges into a school of forage fish 
the slashing motion observed by many fisher- 
men is really a slight changing of direction 
and a grasping for the fleeing prey, the head 
and body describing a relatively small arc. 
Such a grasping motion is not be to identified 
with any such deliberate slashing as Voss {op. 
cit .) reported for sailfish. In his observation 
the prey was herded into a tight school. The 
speed of the predators was not mentioned. 
They merely swam into the closely packed 
school, held together by the remaining sail- 
fish (of unreported number), and thrashed 
with their spears. Presumably all energy could 
be utilized solely to kill fish rather than be 
expended in pursuit. 
It must be assumed that spearfish are not 
always able to concentrate their prey in such 
fashion. In a less dense and guarded school 
of prey, and certainly in a very scattered 
school, it would not be advantageous to 
merely slash. It is entirely possible that the 
normal procedure is to charge into the school 
rapidly snapping the jaws and reaching, with- 
in physical limits, for as much prey as possi- 
ble, with the result that many of the small 
fish are killed or wounded before the school 
scatters. Any effective striking with the spear 
that may occur is probably a secondary and 
fortuitous event. After the school has scat- 
tered the spearfish would likely see the 
wounded or killed fish and would return to 
ingest them. 
These large fishes are obviously built more 
for forward speed than for marked agility. It 
is entirely within reason to assume that a 
spearfish can readily overtake any of the for- 
age fishes or squid, which constitute the bulk 
of its food, and most of the larger fishes. A 
conservative estimate of their speed is at least 
25 miles per hour and bursts of much greater 
speed are probable. A hooked sailfish was 
clocked at 100 yards in three seconds, or 
approximately 68 miles per hour (Walford, 
1937). 
The enormous speed and power of spear- 
fish are dramatically attested by the puncturing 
of ship hulls. Gudger (1940) reported, with 
documentation and photographs, many spears 
found in wooden and copper-clad hulls of 
vessels. Some of these had penetrated fan- 
tastic thicknesses of timber and had broken 
off to furnish irrefutable evidence of speed 
and power. One remarkable example follows: 
"The spear was found to have penetrated 
through the copper sheathing, an inch board 
sheathing, a three inch hard wood plank, the 
solid white oak timber of the ship 12 in. 
thick, through another two and a half inch 
hard oak ceiling-plank, and lastly had per- 
forated the head of an oil cask, where it 
remained immovably fixed so that not a single 
drop of oil had escaped." This total of 18.5 
inches through hardwood, 14.5 of it through 
dense oak, was accomplished by a spearfish 
as the recovered spear was round, unlike the 
flattened blade of the broadbill swordfish. 
San Diego based wooden-hulled fishing ves- 
sels have at times been placed in danger of 
sinking by these fish. The tuna vessel "Rose 
Ann" (San Diego Union, 24 Oct., 1946) was 
struck three feet below the water line off 
Punta Abreojos, Baja California, and was 
forced to use both bilge pumps constantly 
to remain afloat. Subsequent investigation 
revealed five inches of marlin spear projecting 
through the hull planking. Fishermen recalled 
that other vessels in 1942 and 1946 had suf- 
fered the same type of damage. Another re- 
corded ramming occurred off Ecuador, in- 
volving the tuna vessel "Renown" (San Diego 
Union, 22 Aug., 1948). Pumps were operated 
continuously during the homeward voyage. 
When the hull was inspected 18 inches of 
marlin spear was found projected through the 
3-inch hull planking, forming a crack an inch 
wide. 
