MASTERS OF THE WATER-BONY FISHES 205 



and retreat a few times, then leave. The best tactic to use to entice one to come 

 close for photographic purposes is to nonchalantly turn your back and pretend 

 not to notice. The barracuda will approach quite closely. Barracudas have been 

 known to follow persons walking along the shore, another illustration of their 

 curiosity. 



There are times, however, when the barracuda is not just nosy. There are 

 definite records of attack. The bite can always be recognized because it is clean 

 and straight, not like a shark's round and jagged wound. Barracudas usually 

 strike only once, leaving as rapidly as they came. Springer (1943) has analyzed 

 the factors influencing barracuda attack and finds that the danger increases 

 with (1) water over 66° Fahrenheit, (2) increased water turbidity, which 

 impedes the barracuda's vision, (3) the presence of bright colors, shiny or 

 fluttering objects, and (4) fast, sudden, irregular movements across the field 

 of vision. 



Barracudas are diurnal and depend upon their eyesight to hunt. If the 

 swimmer acts like a fish, avoids carrying wounded fish or spearing fish in the 

 barracuda's presence, and does not splash on the surface, there is very little 

 likelihood of attack. 



The flesh of barracudas is good eating. Although it has been reputed in some 

 places to cause "ichthyocism," a form of food poisoning, this seems doubtful 

 according to present knowledge. 



Siviilar Species: The Pacific barracuda, Sphyraena argentea, grows to 5 feet 

 and is found from San Francisco to the south. It is slimmer than the great 

 barracuda. 



Threadfins: Suborder Rhegnopteri 



The one family of threadfins is very much like the mullets, but the unique 

 pectoral fins are split into two parts, the lower one of which is composed of 

 seven or eight threadlike rays. The mouth is under a pronounced snout. They 

 are common in all warm seas except those of Europe. 



Fig. 104. The great barracuda, Sphyraena, is often seen followed hy several skip- 

 jack, Caranx ruber, which -might share in the criinihs of the table. This barracuda 

 was four feet long. 



