372 
PACIFIC SCIENCE, VoL XI, October, 1957 
estimating their availability. Kishinouye 
(1923: 412) states that wahoo do not "make 
a school." Taylor (1951: 278), in discussing 
wahoo off North Carolina, reports that they 
do not form schools but that males and fe- 
males group in pairs at spawning time. From 
our trolling catches close to shore it seems 
that this species tends to form small, loose, 
feeding aggregations, since we found that 
occasionally several wahoo would hit the lures 
simultaneously. Chapman (1946: 166) be- 
lieves that they may form schools, for some 
of the wahoo he caught near Palmyra Island 
had frayed caudal fins, which he attributed to 
crowding in schools. 
Some general knowledge of the vertical and 
horizontal distribution of wahoo is important 
when estimating the availability of this spe- 
cies. These aspects of the distribution can be 
roughly inferred from a comparison of long- 
line catches and troll catches. The longline 
catches are small both close to land and in the 
open ocean. For example, Murphy and Sho- 
mura (1953*, 1953^, 1955) and Shomura and 
Murphy (1955) record only 59 wahoo cap- 
tured on 14 POFI experimental longline fish- 
ing cruises involving numerous stations, some 
close to land. This figure suggests that wahoo 
are never abundant at the depths fished by this 
gear (200-600 ft.). Trolling operations were 
much more productive, but only close to land. 
Only 12 wahoo were caught during 5,500 
hours of surface trolling in the open sea, 
more than 60 miles from land (Murphy and 
Ikehara 1955: 14). In contrast, within a few 
miles of land in both the Hawaiian Islands 
and Line Islands surface catches have averaged 
about 1 wahoo per hour (Table 1). From this 
information we infer that the wahoo prefer 
shallow depths and are more abundant close 
to land. 
Even near islands wahoo are not very 
abundant in the central Pacific. This is sug- 
gested by the low catch rates from surface 
trolling around the Hawaiian and Line islands 
(Table 1). The troll catches obtained near 
the Line Islands during all seasons of the year 
indicate that the species does not occur there 
in sufficient numbers to support a profitable 
commercial fishery. This is also true in Hawaii 
(Welsh 1949^.' 29). Neither does the wahoo 
appear to be very abundant in the Atlantic, 
at least off North Carolina, where Taylor 
(1951 : 278) states that the population is small. 
It is interesting to note from the Line Is- 
lands data (Table 1) that wahoo and yellowfin 
tuna, Neothunnus macropterus (Temminck and 
Schlegel), have a similar pattern of seasonal 
variation in availability. This similarity could 
indicate that environmental or other factors 
TABLE 1 
Results of surface trolling for wahoo and yellowfin tuna in waters 
of the Hawaiian and Line Islands 
AVFR ATT 
WAHOO 
YELLOWFIN 
TIME 
HOURS 
TROLLED 
A. V Jc, ay/ICt-E, 
NUMBER 
OF LINES 
Number 
Catch 
per hour 
Number 
Catch 
per hour 
Hawaii 
Year around, 1947-48 
(Welsh 1949b) 
307 
7.0 
20 
0.07 
23 
0.08 
Line Islands 
April-June 1950 (Bates 1950) 
285.5 
6.1 
178 
0.62 
882 
3.09 
March-April 1955 
142.5 
5.0 
274 
1.92 
438 
3.07 
May -June 1955 
116.0 
6.0 
135 
1.16 
100 
0.86 
July-August 1955 
105.0 
6.0 
83 
0.79 
24 
0.25 
September-October 1955 
182.0 
6.0 
245 
1.35 
171 
0.94 
November-December 1955 
108.0 
6.0 
144 
1.33 
64 
0.59 
January-February 1956 
133.5 
6.0 
267 
2,00 
148 
1.10 
