Farley and Davis: Reproductive dynamics of Thunnus maccoyii 
235 
between 19 and 39 days. Warashina and Hisada 
(1970) reported that lean fish with brownish meat 
have been caught in the Tasman Sea as early in the 
spawning season as November. These lean fish are 
believed to be postspawning females who have re- 
cently migrated from the spawning ground. The ear- 
liest that postspawning females were observed on the 
spawning ground was in October of both the 1993-94 
and 1994-95 spawning seasons. The appearance of 
these postspawning fish on the spawning ground in 
October and again around Tasmania in November sup- 
ports the idea that southern bluefin tuna are capable 
of travelling that distance in approximately one month. 
It also supports the idea that individuals spawn for a 
relatively short time in contrast to the whole season. 
Acknowledgments 
This research was facilitated through a joint moni- 
toring program set up by CSIRO and the Central 
Research Institute for Fisheries of Indonesia. We 
thank the Director of the Research Institute of Ma- 
rine Fisheries, N. Naamin, and S. Bahar, the project 
manager in Indonesia, for their continuing support. 
We especially thank S. Simorangkir, the Director of 
PT (perseroan terbatas) Perikanan Samodra Besar, 
for facilitating biological sampling at the processing 
plant; our field staff, L. Siregar and M. Machmud, 
for collecting data and biological samples; and the 
masters of fishing vessels that voluntarily collected 
ovaries of southern bluefin tuna. We thank D. Le for 
laboratory assistance, K. Haskard and A. Cowling for 
statistical advice, and AFZ and RTMP observers for 
obtaining samples outside Indonesian waters. We 
thank A. Koslow, K. Schaefer, and G. West for re- 
viewing the manuscript and V. Mawson for editorial 
suggestions. This research was supported by Fish- 
eries Resources Research Fund grants from the Aus- 
tralian Fisheries Management Authority. 
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