Notes on the Biology of the Wahoo 
in the Line Islands 
Edwin S. Iversen 1 and Howard O. Yoshida 2 
Incidental catches of wahoo, Acanthocy- 
bium solandri (Cuvier and Valenciennes), have 
been made by the Pacific Oceanic Fishery 
Investigations, a branch of the U. S. Fish and 
Wildlife Service, during experimental tuna 
fishing conducted from 1950 to 1956. The 
exploratory fishing, which extended from 180° 
to 130°W. longitude and from 10°N. to 13°S. 
latitude, has been carried out both close to 
the islands and in the open sea. The bulk of 
our wahoo data came from the Fine Islands, 
which from south to north are: Starbuck, 
Malden, Jarvis, Christmas, Fanning, Wash- 
ington, and Palmyra islands, and Kingman 
Reef. They extend in a general northwesterly 
direction from 5°S. latitude and 155°W. longi- 
tude to 7°N. latitude and 163°W. longitude. 
Although there is no organized fishery in the 
islands, the copra plantation workers (Gil- 
bertese and Ellice islanders) use beach seines 
to capture a variety of lagoon and reef fishes 
and hand lines to catch an occasional tuna or 
wahoo. 
Most of the published reports dealing with 
the wahoo are brief and are concerned pri- 
marily with its occurrence and distribution. 
The presence of wahoo was first noted in the 
Fine Islands by Fowler (1938: 277). Rosa 
(1950: 75-77) lists a number of references 
which are of interest principally to taxono- 
mists. In general the biology of the species 
is poorly known and has not been previously 
considered in the central Pacific. 
1 The Marine Laboratory, University of Miami, 
Coral Gables, Florida. (Formerly Fishery Research 
Biologist, U. S. Fish and Wildlife Service, Honolulu, 
T. H.) 
2 Fishery Research Biologist, U. S. Fish and Wildlife 
Service, Honolulu, T. H. Manuscript received June 
18 , 1956 . 
The wahoo, a member of the order Scom- 
briformes, is a slender, streamlined fish with 
a sharp pointed head (Fig. 1). The mouth is 
large and is armed with razor- sharp teeth. 
Wahoo may weigh over 130 pounds and 
reach a length of nearly 7 feet. The body is 
steel-blue above and pale blue below. A series 
of bluish-black vertical bars, which fade soon 
after death, are present on the sides of the 
body. These fish are said to be very rapid 
swimmers and to make spectacular leaps out 
of the water. 
The species is cosmopolitan in tropical and 
subtropical areas, and ranges at least as far 
north as Hawaii, where it is called "ono.” 
Jenkins (1904: 441) examined wahoo in the 
Honolulu Market and reported that, "This is 
the first record of the species in Honolulu.” 
In Hawaii today the species is of some slight 
importance as a sport fish. It is also sold 
commercially on the fresh fish market in 
Honolulu, but is of secondary importance. 
In 1953 the catch of 50,813 pounds during 
the year was sold for $11,166.94. 
METHODS 
The majority of fish available for this study 
were taken on standard surface trolling gear 
which is described by Bates (1950). This 
method of trolling employs about six lines 
attached to two long poles extending out- 
board, one from either side of the vessel. 
Trolling was mainly carried out from approxi- 
mately 200 yards to 3 miles from the fringing 
reefs of the various islands. Some catches were 
also made on longline (flagline) gear, de- 
scribed by Niska (1954). Longline gear, which 
fishes well below the surface, was generally 
370 
