608 
Fishery Bulletin 99(4) 
Table 4 
Incidence of melanophores on the left lateral side of the trunk and tail (%) in Thunnus thynnus. Each melanophore is recorded for the 
the first to eighth myomeres. 
Myomere 
oize range 
(BL; mm) 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
3.50-3.99 
7 
7 
7 
14 
7 
29 
14 
21 
7 
29 
14 
7 
14 
4.00-4.49 
4 
11 
4 
7 
11 
11 
11 
11 
11 
4.50-4.99 
5 
5 
5 
5 
10 
5 
10 
5 
29 
10 
5.00-5.49 
8 
8 
8 
8 
17 
8 
5.50-5.99 
20 
20 
20 
20 
10 
40 
10 
6.00-6.49 
20 
10 
20 
10 
6.50-6.99 
6 
0 
6 
6 
6 
28 
11 
17 
22 
7.00-7.49 
7.50-7.99 
20 
20 
10 
20 
20 
20 
20 
8.00-8.49 
15 
8 
15 
8 
8 
8 
15 
8.50-8.99 
8 
15 
8 
8 
8 
9.00-9.49 
8 
17 
17 
9.50-9.99 
10 
10 
10 
20 
Table 5 
Incidence of melanophores on the right lateral side of the trunk and tail (%) in 
on the first to nineth myomeres. 
Thunnus 
thynnus 
. Each melanophore is 
recorded for 
Myomere 
£>ize range 
(BL; mm) 
10 11 
12 
13 
14 15 
16 
17 
18 
19 
20 
21 
22 
23 
3.50-3.99 
0 7 
7 
7 
14 7 
21 
14 
21 
14 
29 
14 
7 
14 
4.00-4.49 
4 
11 
4 4 
11 
4 
15 
11 
11 
11 
4.50-4.99 
5 
5 
10 
5 
10 
5 
19 
10 
5.00-5.49 
17 8 
17 
8 
33 
8 
5.50-5.99 
10 
20 
10 
20 
10 
10 
40 
10 
6.00-6.49 
20 
10 
10 
30 
10 
6.50-6.99 
6 
6 
6 6 
6 
28 
11 
17 
22 
7.00-7.49 
20 
10 
20 
10 
10 
7.50-7.99 
10 
10 
10 
20 
20 
10 
8.00-8.49 
31 
15 
8.50-8.99 
15 15 
31 
31 
31 
15 
9.00-9.49 
8 
8 
17 
17 
9.50-9.99 
10 
10 
30 
had anterior lateral line scales. Scales near the anterior 
part of the lateral line appeared at 30.31 mm BL, and 
postorbital scales at 30.81 mm BL. 
Discussion 
Development and growth 
Thunnus thynnus eggs were reported to have a smooth 
chorion, narrow perivitelline space, homogeneous yolk. 
and a single oil globule (Miyashita et ah, 2000), and this 
was reconfirmed in our study. These characteristics are 
similar to those found in other Thunnus eggs: T. thynnus 
from the Mediterranean (Podoa, 1956), T. obesus (Kikawa, 
1953), T. albacares (Harada et al., 1971b; Mori et ah, 1971), 
and T. alalunga (Yoshida and Otsu, 1963). 
The growth strategy of bluefin tuna apparently is to de- 
velop foraging structures before other organs and at an 
early stage to enable feeding on larger organisms. Parts 
of the head were large from early development (Fig. 3) as 
mentioned by Collette et al. (1984) and reached maximum 
