436
A. SUDA:
The other concentration is located along 30
0 -
35 0 S in the southernmost part of the
albacore distribution. The northern group comprises mature individuals and the southern
one immature individuals (SAKAMOTO, 1967).
d) Southern Bluefin (Fig. 1 g and h)
Southern bluefin is distributed in the zonal waters in an east-west direction in the
Sub-Antarctic area with the exceptional northward expansion along the west coast of
Fig. 1 h. Distribution of longline hooking-rate of southern bluefin tuna in the fourth quarter of the
years 1966 -1968
Australia during the fourth and first quarters of the year. Another concentration occurs
along the southern coast of Australia.
2. Distribution at Larval Stage
The distribution of the larvae of 4 large tuna species is given by UEYANAGI (1969).
Their distribution can be summarized as follows:
a) Yellowfin
Yellowfin larvae appear to occur over the relatively low latitudinal area north of 10 0 S.
b) Bigeye
Larval bigeye also seems to spread over the low latitudes north of 10 0 S.