












































0 aad Teal ele eee 
LONGLINE 
OCEANIC STATIONS 
20 iy 
Q=—s== | + 
a 0 | Al | 
a SO eae ] =] 
oO 
LONGLINE 
INSHORE STATIONS | eral 
20 | | N=228 | | cal | 
| | | | 
| 
io} +— | a ifn 
We We 
Ifa fea eo | 
| heel | 
dk | 
o 110 122 ig? 
13.9 1259 185.9 
i. lea Fe Pa Te] ey 
POLE-AND-LINE | | | | 
| MARQUESAS AREA | -- |aeleee| 
BS 50 | ae eae | N#126 WY | 
5S eee 
5 1Z leer eal 
| 
Baro i 
| 
0 | zalenlera| leral eral 
( L ; 98 no 122 
53.9 5. 779 89.9 101.9 113.9 125.9 
LENGTH (CM.) 
Figure 8.--Length-frequency distributions of 
yellowfin tuna caught by longlines at 
oceanic stations, inshore stations, and on 
pole and line in the Marquesas area (pole- 
and-line data from Wilson and Rinkel, 1957, 
and Wilson et al., 1958). 
ranges were about equal and the dominant 
sizes were similar. This situation is at vari- 
ance with that around the LineIslands. Although 
the catches there also are dominated by large 
yellowfin tuna, more small fish (50-110 cm.) 
are caught near the Line Islands than offshore 
(Shomura and Murphy, 1955; Iversen and 
Yoshida, 1957). No yellowfin tuna smaller than 
114 cm. were caught by longlining around the 
Marquesas, although their presence was shown 
by catches made by pole-and-line fishing (fig. 
8). Fish between 90 and 130 cm. were sparsely 
represented in catches of both longline and pole 
and line. This result may indicate that the 
smaller yellowfin tuna in that size range were 
not present in great numbers or that neither 
fishing method adequately samples them. 
The possibility has been mentioned that the 
seasonally greater abundance of yellowfin tuna 
around the Marquesas during the summer may 
have been caused by an influx of large fish. 
30 

SUMMER 
N=214 
20 





PERCENT 
~) 
6 
























0 110 122 146 158 170 
113.9 1259 1499 1619 1139 
LENGTH (CM) 
Figure 9.--Length-frequency distribution of 
yellowfin tuna in the Marquesas Islands, 
arranged by season. 
The length-frequency distribution of fish caught 
in this area, arranged by season (fig. 9) shows 
that no fish longer than 150 cm. were caught 
during winter and that their modal size was be- 
tween 130 and 138 cm. In the summer about 
36 percent of the catch was composed of fish 
longer than 150 cm., and the mode was at 146- 
150 cm, These data should be viewed with 
caution, however, for the winter sample con- 
sisted of only 14 yellowfin tuna. 
Length-frequency distributions of skipjack 
tuna, albacore, and bigeye tuna are presented 
in figure 10. These tunas were not caught in 
sufficient numbers to warrant detailed com- 
ments. The modes in the length-frequency dis- 
tributions of bigeye tuna are indefinite; however, 
85 percent of the bigeye tuna were between 126 
and 178 cm.long. The size distribution of alba- 
core was relatively compact: All of the speci- 
mens measured between 90.6 and 111.6 cm., a 
length range of only 21cm. Skipjack tuna ranged 
from 46.6 to 83.1 cm., and had a mode at 74- 
78 cm. 
SUMMARY 
1. This report is based on the tuna catches 
made by longline fishing on three cruises 
around the Marquesas Islands and across the 
Equator on long. 132° and 150° W, Six hundred 
forty-two tuna were caught, of which 438 were 
yellowfin, 102 bigeye, 51 albacore, and 51 
skipjack. 
